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Beryllium Journal Articles Related to Dentistry 1960's 1970's 1980's 1990's 1960's (1966). “Beryllium ion inhibition of the nucleating macromolecule (s) in saliva extract.” J Dent Res 45(3): 978.   Wszolek, B., E. Kukiel, et al. (1967). “The construction of individualized plastic teeth from beryllium- copper molds.” J Prosthet Dent 17(3): 251-60.   Shadurskii, K. S., B. V. Dubovik, et al. (1969). “The effect of fluoride complex formation on fluoride uptake and retention in human enamel.” Arch Oral Biol 14(5): 521-31. 1970's Berg, J. W. and F. Burbank (1972). “[Studies and protective measures].” Dent Labor (Munch) 20(10): 42-5.   Wessel, G., K. Stammberger, et al. (1972). “Patterns of change in human mandibular arch width during jaw excursions.” Arch Oral Biol 17(4): 623-31.   FitzGerald, M. X., C. B. Carrington, et al. (1973). “An evaluation of nonprecious alloys for use with porcelain veneers. Part II. Industrial safety and biocompatibility.” J Prosthet Dent 30(4): 432-41.   Bugryshev, P. F., I. Moskalev Iu, et al. (1974). “Status report on base-metal crown and bridge alloys.” J Am Dent Assoc 89(3): 652-5.   Kuznetsov, A. V., O. G. Matveev, et al. (1974). “Beryllium toxicity.” Greater Milw Dent Bull 40(4): 96-7.   (1975). “Changes in the composition of a nickel-base partial denture casting alloy upon fusion and casting.” Aust Dent J 20(1): 14-8. Three series of tensile test pieces were produced using a nickel-base partial denture casting alloy. For the first series induction heating was employed for melting the alloy, for the second a resistance crucible, and for the third an oxy-acetylene torch. In each series the same metal was cast sequentially five times, following which samples of the alloy were subjected to a ten element quantitative analysis to ascertain compositional changes associated with the three methods of fusion.   Jones, H. (1975). “[Nickel - latest fear in the dental laboratory].” Dent Labor (Munch) 23(5): 477-8.   Moatamed, F., M. J. Karnovsky, et al. (1975). “Factors affecting airborne beryllium concentrations in dental spaces.” J Prosthet Dent 33(2): 210-5. Air sampling for beryllium concentrations produced during finishing procedures for a beryllium-containing alloy was conducted in two rooms with capacities of 700 and 10,000 cubic feet. The clearance rate of beryllium in the air and the effect of ventilation and room size on these concentrations were investigated. With local lathe ventilation, no beryllium was found. Without local lathe ventilation, mean 10 minutes concentrations of about 23 mug per cubic meter were found at the breathing zone of the lathe operator in both rooms. At 4 and 8 feet from the breathing zone, sizable concentrations of beryllium above the maximum acceptable standard were found only in the small room. These levels decreased to zero 10 minutes after completion of the finishing and polishing procedure. It was concluded that there was little hazard to dental personnel when local lathe ventilation was used; however, our finding of high concentrations of beryllium in the air when lathe ventilation was not used indicates that continued vigilance must be maintained. Willner, G. (1975). “[Beryllium in dental technic].” Quintessenz Zahntech1(11): 61-2.   Barna, B. P., T. Chiang, et al. (1976). “[Risks incurred by dental technicians working on metallic prostheses].” Soz Praventivmed 21(4): 139. A short description of working conditions is given. Out of 25 radiographs, 5 show possible pneumoconiosis due to hard metal and one is abnormal. The hazards due to the presence of beryllium in numerous alloys is emphasized as well as the necessity of technical and medical supervision in dental laboratories. Adrian, J. C. and E. F. Huget (1977). “Tissue response to base-metal dental alloys.” Mil Med 142(10): 784-6.   Steenland, K., D. Loomis, et al. (1977). “[A study on the effects of beryllium addition upon biological and physical properties of dental cobalt-chromium alloys (author's transl)].” Shika Rikogaku Zasshi 18(44): 254-69. The effects of beryllium addition to a dental cobalt-chromium alloy on biological compatibility as well as physical properties were examined and the following results were obtained. 1. Slight, but significant depression of the rates of cell multiplication was obtained with the experimental groups, i.e., alloy with no beryllium added as well as alloys with beryllium of up to 3.0 per cent by weight, compared to control group, which contained no alloys, but a glass disk. Within the experimental groups no significant difference in the rates of cell multiplication was found between the alloys with beryllium addition ranging from zero up to 2.0% by weight. However, alloy with 3.0% beryllium yielded slight, but significant depression of the rates of cell multiplication. Pure beryllium metal revealed severe cytotoxicity. 2. Cell morphology of the experimental groups confirmed the above results of the rate of cell multiplication. 3. Increase of beryllium within the alloys resulted in increase of tensile strength as well as Rockwell hardness, while elongation and fusion temperature were brought down. 4. Metallographs of alloys and cast specimens confirmed the results of the mechanical properties. The more beryllium was added, the smaller was the alloy crystal observed. 5. Loss of beryllium in the alloy was found during such procedures as melting each metal for making up alloys and casting. It is considered that the present results will be able to lend suggestions to beryllium use in dentistry with regard to biological compatibility as well as physical properties.   Floersheim, G. L. (1978). “[The corrosion behavior of the bonded alloy Ultratek].” Dtsch Zahnarztl Z 33(12): 833-6. Ultratek crystal has a multiphasic structure; beryllium is concentrated in one phase. Under the influence of the solvent, this phase is attacked and the Be salts are released. Measurement of atom absorption revealed that the amount of beryllium actually released is extremely low. Under the influence of reagents present in the buccal cavity or which come in contact with it, the amount of beryllium is 10(4) times lower (per 1 cm2 free surface metal per day) than the maximal values permitted according to the calculation of an earlier MAC value (maximal concentration for working conditions).   Williams, T. R., C. E. Johnson, et al. (1978). “Be, Li, and Na redistribution near a porcelain/Ni alloy interface shown by ion microprobe mass analysis.” J Dent Res 57(2): 233-6. During porcelainization the non-preoxidized alloy develops a Be-rich reaction zone in the interface which separates a Be-depleted alloy from a Li and (to a lesser extent Na) depleted region of the ceramic. Thus, Be diffuses to the interface through the alloy Be degrees leads to Be++ + 2 e- occurs at the interface; some of the electrons are electronically conducted to the porcelain-air interface where they are consumed as 2 e- + 1/2 O degrees 2 leads to O=, and the resulting negatively charged porcelain surface attracts Li+ (and Na+).   Williams, T. R., P. G. Winchell, et al. (1978). “Dental porcelain/Ni alloy interface reactions and their effective prevention.” J Dent Res57(4): 583-91. In a Be-bearing Ni alloy porcelainized without preoxidation, Be diffuses to the interface, oxidizes, and oxygen is supplied by the atmosphere at the porcelain surface and by reduction of SiO2 at the porcelain-alloy interface. On the alloy side of the interface, pits develop locally and near them Ni and Cr oxidize. In the oxide, Ni and Si are reduced to form nickel silicides. Preoxidation of the alloy prevents Be oxidation and Si reduction for several hours of porcelainization.   Caccialanza, M., G. Eulisse, et al. (1979). “Toxic elements in silicate cements.” Scand J Dent Res 87(6): 466-9. Six brands of silicate cements have been characterized by means of optical emission spectrography with respect to the contents of elements in minor or trace quantities in a search for presence of possible toxic elements. Beryllium was observed in two powders at levels of 1.3 and 1.6% Cadmium was found in two powders at levels of 0.02 and 0.03%. Lead was measured in three powders at levels of 0.001-0.003% . Bismuth, boron, copper, gallium, iron, manganese, titanium, tin and zirconium were found in various brands in either powder or liquid at levels of 0.001-0.1%. Upper limits of the amounts of the various elements that might be transferred to the gastrointestinal tract after dissolution of the cement matrix in the oral cavity have been calculated. 1980's Williams, J. R., G. Galloway, et al. (1980). “Casting alloys.” N Y J Dent 50(2): 45.   Brockhurst, P. J. and R. W. Cannon (1981). “Alloys for crown and bridgework.” Aust Dent J 26(5): 287-94. The requirements of alloys for metal-ceramic crowns and bridgework are examined. The functional requirements and manipulative behaviour and cost of cheaper alternatives to high gold alloys are discussed. All types use--high gold, reduced gold, silver palladium and base metal--appear to function satisfactorily in the mouth. Nickel and beryllium do not appear to be health hazards. Dental laboratory procedures and materials must be chosen to suit the type of alloy employed, although all alloy types appear suitable for crown and bridgework. The cost of alloy must be carefully examined in the context of total cost to the patient, and the use of alternatives to gold alloys in many cases may not warrant the required changes to laboratory procedures, but the saving is real, and can make permanent restorations available to greater proportion of the community.   Nagayama, M., T. Oka, et al. (1982). “Localization of sudanophil material at the sites of calcification in dentine, and the compact bone and epiphyseal cartilage plate of tibia in the rat given beryllium carbonate.” J Toxicol Sci 7(3): 219-27. The localization of sudanophil material at dentine, the compact bone and epiphyseal cartilage plate of tibia of rat given beryllium carbonate was examined. Sudanophil material was seen at the boundary parts between dentine and widened predentine, and between widened preosseous matrix and calcified bone, but it was not seen at the area corresponding to the zone of provisional calcification. These facts suggest that the localization of sudanophil material in hard tissue of rat with Be rickets was similar to that in vitamin D deficient-induced rickets. This sudanophil material was not disappeared by the enzymes such as papain, pepsin and hyaluronidase as described in vitamin D deficient- induced rickets (Irving, 1960, 1963). Accordingly, it was suggested that the substance was not proteins and mucopolysaccharide.   Porter, D. J. (1982). “Health hazards associated with base metal alloys.” Aust Soc Prosthodontists Bull 12(2): 4-7.   Isomura, M. (1983). “[Relation between oxidation and composition of porcelain fused-to Ni-Cr alloys].” Aichi Gakuin Daigaku Shigakkai Shi 21(4): 615-30.   Mullen, A. L., R. E. Stanley, et al. (1983). “The tensile strength and appearance of solder joints in three base metal alloys made with high- and low-temperature solders.” J Prosthet Dent 50(3): 362-7.   Papastefanou, C., A. Ioannidou, et al. (1983). “Multiple recast of a nickel-chromium-beryllium alloy.” J Prosthet Dent 50(2): 198-9.   Rees, P. J. (1983). “Resin-bonded retainers. Part I: Resin bond to electrolytically etched nonprecious alloys.” J Prosthet Dent 50(6): 771-9. Nonprecious Ni-Cr casting alloys can be electrolytically etched to yield a highly retentive surface for micromechanical bonding of dental resins. The acid, current density, and etching time to achieve the retentive features are specific for each alloy. Conditions for etching one beryllium-containing and one non-beryllium-containing alloy are described. The tensile strength of a resin system to these alloys has been determined to be over two times the accepted value of the resin bond to acid-etched enamel.   Rom, W. N., J. E. Lockey, et al. (1983). “Observations on nickel-free, beryllium-free alloys for fixed prostheses.” J Am Dent Assoc 106(1): 36-8. Mechanical properties, electrochemical behavior, heat treatment response, micro-structural features, and compositions of two proprietary nickel-free, beryllium-free fixed prosthodontic alloys were studied. The alloys showed compositional and microstructural differences. Mechanical property values of Biocast and Neobond II are comparable with those of base metal alloys for removable partial dentures. The high hardness, high modulus of elasticity, and low elongation impede adjustment, adaptation of margins, and polishing of the final restoration.   Vermilyea, S. G., J. J. Tamura, et al. (1983). “Nonprecious alloys for use in fixed prosthodontics: a literature review.” J Prosthet Dent49(3): 363-70. The physical properties of nonprecious alloys can differ significantly from those of alloys containing a high percent of gold. Relationships among constituents, physical properties, and handling characteristics of base metal alloys were surveyed. Toxicity of nickel, beryllium, and their compounds was discussed with attention given to the dental environment. Allergic contact dermatitis appears to be a health risk to certain patients from nickel-containing prostheses. Beryllium dust is apparently not a hazard in properly ventilated and exhausted grinding and polishing areas. Lack of data on nickel-related health problems in dental laboratory workers should be interpreted with caution. This article also reviewed research on porcelain bonding and corrosion of nonprecious alloys. Although this research cannot yet predict an alloy's porcelain bonding behavior in mouths, little or no porcelain bond problems have been reported. A few controlled clinical studies report little corrosion in up to 4 years.   Alster, T. S. and C. M. Williams (1984). “The biocompatibility of metals in dentistry.” Cda J 12(10): 17-9.   Brancaleone, P., B. Weynand, et al. (1984). “Pneumoconiosis and exposures of dental laboratory technicians.” Am J Public Health 74(11): 1252-7. One hundred and seventy-eight dental laboratory technicians and 69 non-exposed controls participated in an epidemiological respiratory study. Eight technicians who had a mean of 28 years' grinding nonprecious metal alloys were diagnosed as having a simple pneumoconiosis by chest radiograph. Mean values for per cent predicted FVC and FEV1 were reduced among male nonsmoker technicians compared to male nonsmoker controls; after controlling for age, there was also a reduction in spirometry with increasing work-years. An industrial hygiene survey was conducted in 13 laboratories randomly selected from 42 laboratories stratified by size and type of operation in the Salt Lake City, Utah metropolitan area. Personal exposures to beryllium and cobalt exceeded the Threshold Limit Values (TLVs) in one laboratory. Occupational exposures in dental laboratories need to be controlled to prevent beryllium-related lung disorders as well as simple pneumoconiosis.   Goodhead, D. T., R. J. Berry, et al. (1984). “Intraoral behaviour and biocompatibility of gold versus non precious alloys.” J Biol Buccale 12(1): 3-16. The costs of traditional dental gold alloys have increased rapidly over the last fifteen years, and numerous attempts have therefore been made to develop and produce less expensive alternatives for use in the manufacture of fixed dental appliances. A review is presented of the various types of alloys currently available in the western world, as well as of the biological, technical and clinical aspects of their use in dentistry. Special attention is paid to the possible risks of various types of pathological reactions associated with alternative alloys containing nickel, beryllium or cadmium. Technical aspects covered include constructional problems and those associated with casting, finishing and the clinical adjustment of fixed appliances produced by traditional and alternative alloys. In conclusion, it is stated that even if rapid progress in this area makes long- term predictions difficult there is no evidence at present to suggest that the costs of dental treatment have in general become noticably lower to the patients when alternative alloys have been used instead of traditional gold based ones.   Hawbolt, E. B., M. I. MacEntee, et al. (1984). “An investigation of the tensile strength of nickel-chromium alloy dental solder joints.” J Prosthet Dent 52(5): 666-72.   Jung, P., J. M. Wolff, et al. (1984). “Workshop: biocompatibility of metals in dentistry. National Institute of Dental Research.” J Am Dent Assoc109(3): 469-71.   McNeill, K. G., D. J. Borovnicar, et al. (1984). “A castability study of nonprecious ceramometal alloys.” J Prosthet Dent 51(4): 490-4.   Phan, B. C., P. Cheung, et al. (1984). “Laser-welded vs soldered nonprecious alloy dental bridges: a comparative study.” Lasers Surg Med 4(2): 207-13. The high cost of gold alloy has caused the dental profession to begin substituting nonprecious alloy for the framework in porcelain fused to metal bridges. Especially in long- span bridges it may be advantageous to make multiple castings and then join them for a better fit. As opposed to the highly successful soldering of gold, soldered nonprecious alloy bridges have a great failure rate in the mouth. Removal of and remaking of the bridges is thus the result. This study compares nonprecious units that have been laser-welded with those conventionally soldered. Seven identical bridges of three units were cast in a popular alloy composed of 74-78% nickel, 12-15% chromium, 4-6% molybdenum, and 1. 8% maximum beryllium. One served as a control, while the remaining six were all cut in the same place. Of these, three were soldered with a gas oxygen torch. The other three were welded with a Nd-YAG laser. Better and stronger joints unlikely to fracture in the mouth were found with the laser-welded specimen.   Sbordone, L., P. Police, et al. (1984). “[In vitro toxicity of dental materials used in restorative and prosthetic dentistry. II. Alloys, amalgams and their constituent elements].” Minerva Stomatol 33(6): 973-8.   Zaikina, T. I., I. Moskalev Iu, et al. (1984). “In vitro cell response to cobalt-chromium-molybdenum alloy containing beryllium.” J Prosthet Dent 51(6): 790-6.   Behbehani, K., D. I. Beller, et al. (1985). “Quantization of nickel and beryllium leakage from base metal casting alloys.” J Prosthet Dent54(1): 127-36.   Berry, J. P., F. Bertrand, et al. (1985). “Casting accuracy of a nickel and beryllium-free cobalt- chromium alloy for crown and bridge prostheses and resin- bonded bridges.” Swed Dent J 9(3): 105-15. In the 1970's economic factors dictated the development of alternatives to gold alloys in dentistry in the USA and in Europe. A similar development has not occurred in Sweden because of different laws. Alloys that contain nickel and beryllium present a health hazard and are therefore of little interest to the Swedish market. A review of the literature shows that castings of base-metal alloys are less accurate than castings of conventional gold alloys and of low gold alloys. However, in long-span-bridges and in thin resin-bonded cast restorations, their physical and mechanical properties are superior to those of the gold alloys. In this study the casting accuracy of a nickel- and beryllium-free cobalt-chromium alloy, Neobond II Special, is investigated. Neobond II Special was found to be less accurate than Sjödings C-guld. The marginal discrepancies of the castings were small, however, when the castings were oversized. It also proved to be technique sensitive to conventional dental laboratory procedures. Thus, it seems difficult to get castings with an acceptable retention as well as small marginal discrepancies when using the base-metal alloy.   Hallenbeck, W. H., S. P. Breen, et al. (1985). “Beryllium localization in base metal dental casting alloys.” J Biomed Mater Res 19(7): 747-50. Investigation of dissolution of base metal dental casting alloy constituents in aqueous solutions revealed an unexpectedly high level of beryllium as compared with the other constituents. Analysis of atomic emission spectroscopy is presented here showing the outer surface (0-100 A) is decidedly enriched in beryllium as compared with the bulk composition of the alloy. This localization is consistent in all samples and forms of the alloy tested.   Hansson, O. (1985). “Report on base metal alloys for crown and bridge applications: benefits and risks. Council on Dental Materials, Instruments, and Equipment.” J Am Dent Assoc 111(3): 479-83. Despite the widespread use of nickel-based alloys, claims for the safety of these alloys have not yet been accepted universally. The allergenic effects of nickel on dental patients and the potential toxic effects of nickel and beryllium on laboratory technicians continue to cause concern within the dental profession. The systemic response to metallic nickel and nickel compounds as a result of intraoral corrosion and dissolution of nickel-based restorations over extended periods have not been studied adequately. The dental profession may be overgeneralizing the relative safety of nickel alloys because of the lack of allergy- induced intraoral lesions observed in private practices. Additional animal studies are needed to characterize the acute and chronic toxicities of nickel compounds. The potential for dermatologic and systemic effects that may occur in patients and dental personnel because of exposure to cobalt alloys must not be overlooked. Although sensitivity reactions may be of some concern, the toxicity potential of cobalt- chromium alloys appears to be insignificant. Little research has been done to determine the carcinogenic potential of nickel in dental laboratory technicians. In addition, animal and human studies are needed to determine the effect of nickel and beryllium exposure on the reproductive system. In the interim, specific equipment and facilities that minimize dust and vapor exposure to dental technicians should be identified to reduce airborne concentrations of nickel and beryllium in commercial dental laboratories to levels well below those established by the Occupational Health and Safety Administration.(ABSTRACT TRUNCATED AT 250 WORDS)   Morel, C., A. Cavigneaux, et al. (1985). “[Beryllium (Be) and compounds].” Rev Fr Prothes Dent(61): 58-9, 61-4.   Nadeenko, V. G., I. R. Goldina, et al. (1985). “The allergenic potential of metals in dental alloys.” Natl Dent Assoc J 42(1): 25-7, 34.   Sidransky, H., C. N. Murty, et al. (1985). “Safeguarding the physical well-being of dentists.” J Am Dent Assoc 110(1): 16-24.   Anusavice, K. J. and I. Shafagh (1986). “Inert gas presoldering of nickel-chromium alloys.” J Prosthet Dent 55(3): 317-23.   Dixon, D. L., L. C. Breeding, et al. (1987). “A new chemical method for etching metal frameworks of the acid-etched prosthesis.” J Prosthet Dent 58(4): 421-3. Alloys containing beryllium, silicon, boron, and all nickel base alloys are etched well by the method described, with the exception of Fore alloy manufactured by the Unitek Corp. Alloys containing chrome and cobalt cannot be etched with Met-Etch gel. The advantages of using this method of chemical etching are (1) this conservative procedure can be performed in two clinical sessions, (2) the etching of the framework can be effectively controlled by the dentist or the laboratory technician, and (3) if the metal framework is dislodged it can be cleaned, etched, and reattached during the same appointment.   East, B. W. (1987). “Resin bond to electrolytically etched cobalt-chromium alloys.” Scand J Dent Res 95(1): 82-6. Disks of four cobalt-chromium alloys were electrolytically etched and bonded together using a microfilled restorative resin. The bonds of the resin to two of the tested alloys, Bondi-loy and Vitallium, showed tensile strengths of approximately 18 MPa. The bonds were significantly stronger than those obtained using the other two alloys, Dentitan and Novarex. The tensile bond strengths of etched Dentitan and Novarex were 5.3 and 7.5 MPa respectively. The etched and debonded surfaces were studied in SEM.   Goshima, T., Y. Goshima, et al. (1987). “Tensile strength analysis of midpontic soldering.” J Prosthet Dent 57(6): 696-703. A total of 120 three-unit fixed partial dentures were made by using a latex mold to produce uniform wax patterns. Four groups were used to compare the tensile strength of connectors with interproximal solder, midpontic vertical solder, midpontic diagonal solder, and a control of one- piece castings. Three different metals were tested and the tensile load required to fracture the samples as well as the fracture sites were recorded. The following was found: Soldering the interproximal connector area produced the weakest solder joints, regardless of metal tested, at p less than .001. There was no significant difference in the fracture loads between midpontic vertical soldering and midpontic diagonal soldering with all three metals at p less than .01. There was no significant difference in fracture loads between midpontic soldering and unit casting with all three metals at p less than .01. The extreme variations in fracture loads when soldering nickel-chrome- beryllium confirms the technique sensitivity of presoldering this alloy.   Harrison, G. H., C. R. Cox, et al. (1987). “Corrosion in vivo and in vitro of a commercial NiCrBe alloy.” Dent Mater 3(3): 125-30.   Kelly, J. R. and W. A. Brantley (1987). “Evaluation of biangular reflection photometry for quantitative study of etched alloy surface roughness.” J Dent Res 66(8): 1350-5. Biangular reflection photometry was correlated with quantitative stereology and direct pit-depth measurements for an electrolytically etched nickel-chromium-beryllium alloy. Effects of viewing angle, viewing aperture, and plane polarization of incident and viewing light were also studied. The results showed that architectural changes in the etched metal surface could be quantitatively described with the use of reflection photometry. An off-specular peak, located at an angle of reflection considerably different from the angle of incidence, was observed to have an intensity comparable with that of the specular reflection peak. Viewing aperture was found to affect one's ability to distinguish among degrees of surface roughness.   Kerr, G. D., T. D. Jones, et al. (1987). “Alternative metal ceramic alloys. Part II: Base metal alloys.” Refu Hashinayim 5(4): 6-12.   McDaniel, D. H., K. Ash, et al. (1987). “Tensile bond strength of low-fusing solder joints with the use of a nickel-chromium-beryllium base metal alloy.” J Prosthet Dent 58(5): 563-9.   Pahariya, Y. K., N. K. Agrawal, et al. (1987). “[The porcelain firing furnace, using infrared radiation heating elements. 2nd report. Reference to the shear bond strength of non-precious alloys].” Nippon Hotetsu Shika Gakkai Zasshi 31(5): 1208-15.   Kolodney, H., Jr., A. D. Puckett, et al. (1988). “The effect of limited beryllium additions on a Ni-Cr alloy.” J Prosthet Dent 60(6): 688-92.   Stafford, T. J. and O. T. Tan (1988). “Microanalysis of thin oxide film formed by high-temperature oxidation of commercial Ni-Cr alloy containing Be for metal- porcelain bonding.” Dent Mater J 7(1): 24-38.   Symons, J. E. and D. T. Jones (1988). “[Biomate-C (R*) for ceramo-metal frameworks].” Rev Fr Prothes Dent(5B): 53, 56-7, 60.   Awschalom, M., I. Rosenberg, et al. (1989). “[Composition and morphology of oxides on porcelain fused to Ni-Cr alloys. Be containing alloys].” Aichi Gakuin Daigaku Shigakkai Shi 27(2): 383-96. Bonding strength between porcelain and Ni-Cr alloy for the porcelain fused-to metal crown in which Be is contained in the alloy is known to be higher than those in which Be is not contained. Since, bonding between porcelain and alloy is the reaction of oxides and porcelain, the bonding is thought to be influenced by the quality the oxides film which forms on the alloy surface. The purpose of this study was to determine the composition and morphology of the oxides formed on both Be containing and non-Be contained Ni-Cr alloys. The oxides analysis was done using an EPMA and Auger analysis. Also, the Porcelain/Ni-Cr alloy interface was observed by a scanning electron microscope (SEM). The following results are indicated from this investigation: 1. The oxides from the alloys not containing Be are corundum type Cr2O3 and spinel type NiCr2O4. These oxide layers are uniform, thick and porous and the adhesion to alloy is poor. 2. The oxides from alloy containing Be is BeO only. The BeO is uniform, thin and condensed. The adhesion to the alloy is good. 3. The oxide layer formed when the porcelain is fused to alloy containing Be is thin (1 micron average) and has good adhesion to alloy. 4. Be is selectively oxidized and controlled the form of Cr2O3 and NiO.   Johansson, B. I., L. C. Lucas, et al. (1989). “Corrosion of copper, nickel, and gold dental casting alloys: an in vitro and in vivo study.” J Biomed Mater Res 23(A3 Suppl): 349-61. The corrosion behavior of commercially available copper, nickel, and gold alloys for dental castings was investigated. The alloys investigated included: three copper alloys ( 76-87Cu, 6-11A1, 0-12Zn, 1-5Ni, 0-4Fe, 0.5-1.2Mn), two nickel alloys (68-78Ni, 12-16Cr, 4-14Mo, 0-1.7Be), and one gold alloy (77Au, 14Ag, 8Cu, 1Pd). Anodic and cathodic polarization curves, long-term immersion tests in saline and artificial saliva solutions, and dog crown studies were conducted to evaluate both the in vitro and in vivo corrosion characteristics of the alloys. All evaluations conducted demonstrated that the copper alloys were highly susceptible to corrosion attack. High corrosion currents were observed in the in vitro tests, and SEM of the alloys specimens showed significantly altered surfaces. The anodic polarization curves predicted that the beryllium-containing nickel alloy should be susceptible to localized corrosion and SEM revealed an etched surface with corrosion of certain microstructural features. No significant corrosion was predicted or observed for the non-beryllium nickel alloy and the gold alloy. The in vitro corrosion evaluations predicted the in vivo corrosion behavior for the alloys. Since the three copper alloys and the beryllium-containing nickel alloy demonstrated significant corrosion under the tested conditions, the use of these alloys for restorative procedures is questionable due to the release of significant levels of selected ions to the oral cavity.   Jones, D. D., G. F. Williams, et al. (1989). “A status report of possible risks of base metal alloys and their components.” J Prosthet Dent62(2): 234-8. Sensitivity to base metal alloys and the components, both generalized skin reactions and local reactions, has been well documented. With the present trend toward increased use of these alloys by the dental profession, the short- and long-term implications of their use needs to be investigated. This article reviews the background, intake, and current use of two of the most commonly used metal alloys and their components. It also describes their mechanisms of action at the cellular level, the hazard to technicians, patients, and dentists, and the current health standards for airborne exposure in dental laboratories.   Ponomarev, M. A., V. P. Timofeev, et al. (1989). “Evaluation of a chemical etching solution for nickel-chromium- beryllium and chromium-cobalt alloys.” J Prosthet Dent 62(5): 516-21. Two chemical etching solutions were capable of providing micromechanical retention in two nickel-chromium-beryllium alloys and in a chromium-cobalt alloy. A resin matrix was used to verify the quality of etching on the metal surfaces. The chemical etching solutions created high microretentive surfaces in nickel-chromium-beryllium alloy but the chromium- cobalt alloy surfaces after etching were less retentive. Improved chemical etching technique should encourage expanded use of the resin-bonded retainers.   Rickard, M. T. (1989). “Corrosion of dental copper, nickel, and gold alloys in artificial saliva and saline solutions.” Dent Mater 5(5): 324-8. The purpose of this investigation was to study the tarnish and corrosion of three commercial copper alloys, three experimental copper alloys, two nickel alloys, and one high-gold alloy by exposing the specimens for four weeks to artificial saliva and saline solutions. Half of the specimens were brushed, and the solutions were changed regularly. The copper-based and the beryllium-containing nickel alloys exhibited significant surface alterations after exposure to either solution. The potential of elevated release of ions to the oral cavity and to the target organs by some of the investigated alloys should be considered if dental usage of these alloys is to be extended.   Triolo, P. T., W. P. Kelsey, 3rd, et al. (1989). “Cleft palate rehabilitation using a resin-bonded split- post prosthesis.” J Prosthet Dent 61(4): 395-8. For the patient described in this report a nonprecious metal alloy that contains neither beryllium nor nickel was used. The retainers were sandblasted with 50 microns alumina and cemented by using a resin that bonds chemically to metal. With good oral hygiene and regular review the resin-bonded split-post prosthesis should provide a long period of service. In contrast to conventional fixed restorations, failure of this type of prosthesis is not highly destructive and other restorative options are still possible if failure occurs.   Watanabe, T. (1989). “[Sandwich type dental magnetic devices of Nd-Fe-B magnet and permendur].” Shika Zairyo Kikai 8(4): 539-45. Nd-Fe-B magnets have a very high maximum energy product (BH max), which is defined as the attractive strength between a magnet and opposing magnetic materials. Permendur (Fe- 49 Co-2 V) has the greatest magnetic saturation (Bs), which makes it strongly magnetized. If magnetic retainers were made with Nd-Fe-B magnets and a permendur yoke, they would be small and have strong retention. The purpose of this investigation was to develop small dental magnetic devices with Nd-Fe-B magnets and permendur yokes. The magnetic devices form sandwich-type magnetic circuits with magnetic stainless steel keepers. A 4 x 3 x 2 mm rectangular prism Nd-Fe-B magnet was used. The magnet was sandwitched between the semi-columnar yokes. To protect the magnet from corrosion, the devices were encapsulated with 304 stainless steel by silver brazing and adhesion bonding of a stainless steel tube and foil. The optimum cross-sectional area of the yoke was determined experimentally. The dimensions of the devices were phi 5 x 3.5 mm for 4 x 3 x 2 magnet. The breakaway retention for a keeper of magnetic stainless steel (Type XM 27) was 852 g on average. This breakaway retention is sufficient for dental prosthetic applications.   Williams, W. J. (1989). “Behaviour of urinary beryllium in general population and in subjects with low-level occupational exposure.” Med Lav 80(5): 390-6. Occupational exposure to beryllium (Be) is nowadays much lower than in the past. While the classic Be diseases, such as berylliosis, are clearly on the decline, attention is currently being focussed on the immunological and carcinogenic effects of Be, which suggest that subjects with low-level occupational exposure should also be accurately controlled. Urinary Be (BeU) values were determined in a sample of the general population and in a group of dental technicians exposed to environmental Be concentrations ranging from 0.04 to 1.7 micrograms/m3. The mean BeU values of these workers (0.34 micrograms/l) were higher than those of the general population (0.26 micrograms/l) and the subgroup of dental technicians exposed to higher Be air concentration showed higher BeU levels. Although at present the relationships between external and internal dose and between internal dose and early effects, are not known, we believe that biological monitoring supplies useful information on occupational Be exposure. 1990's Atta, M. O., B. G. Smith, et al. (1990). “Bond strengths of three chemical adhesive cements adhered to a nickel-chromium alloy for direct bonded retainers.” J Prosthet Dent 63(2): 137-43. Sandblasted surfaces of a beryllium-free, nickel-chromium alloy were bonded with one of three chemical adhesives. After either immersion in water for up to 6 months or thermal cycling between 5 degrees and 60 degrees C for 500 cycles, the bonded specimens were tested for both shear and tensile strength. The highest values of tensile and shear bond strengths were found with Panavia Ex material, and these values showed no significant changes after thermal cycling. For ABC cement and for Super-Bond C & B material, the strength of the bond was significantly improved with thermal cycling. However, immersion in water for 6 months caused a significant decrease in the strength of the bond of specimens adhered with ABC cement.   Fabry, L., A. Leonard, et al. (1990). “Tensile bond strengths of an electrolytically and chemically etched base metal.” Int J Prosthodont 3(1): 93-7. This study compared the tensile bond strengths of a Ni- Cr-Be alloy electrolytically etched and chemically etched with three commercially available gels. Etched metal cylinders were bonded end-to-end with a resin luting agent and subsequently tested for tensile strength. Mean bond strengths and the character of bond failure were recorded. Significant differences were found between the electrolytically and chemically etched specimens.   Haywood, V. B., B. E. Kanoy, Jr., et al. (1990). “Thermal removal of composite resin: effect on rebonding etched metal.” J Prosthet Dent 63(3): 289-91. If a correctly etched-metal, resin-bonded fixed partial denture debonds, one recommendation for reuse is to clean the prosthesis by oven burnout, then to recement it without reetching. The purpose of this study was to determine whether the tensile strength of the bond of composite resin cement to either electrolytically or chemically etched metal was affected by earlier removal of residual resin with a burnout procedure. Pairs of rods made of nickel-chromium-beryllium were electrolytically or chemically etched according to accepted techniques, then bonded end-to-end with an enamel bonding agent and composite resin cement in an alignment apparatus. The rods were stored for 24 hours in 37 degrees C water, then debonded to determine the tensile bond strengths in megapascals. After debonding, the rods were placed in the burnout oven at 510 degrees C for 30 minutes. The rods were then ultrasonically cleaned in ethyl alcohol for 6 minutes. The pairs were rinsed under running water and then rebonded and debonded nine more times under the same conditions. A linear regression analysis revealed that there was no statistically significant difference (p less than 0.05) in the tensile strength of the bonds after repeated thermal cleanings and bondings. Correctly etched metal, resin-bonded fixed partial dentures may be recemented without re-etching after thermal cleaning without a statistically significant loss in the tensile strength of the bonds.   Kohli, S., W. A. Levine, et al. (1990). “[Injection technic without gallium and beryllium].” Quintessenz Zahntech 16(4): 399-409.   Krueger, G. E., A. M. Diaz Arnold, et al. (1990). “A comparison of electrolytic and chemical etch systems on the resin-to-metal tensile bond strength.” J Prosthet Dent 64(5): 610-7. This investigation compared the tensile bond strengths of a nickel-chromium-beryllium alloy etched electrolytically and etched with a commercially available chemical gel. The number of applications and the thermal conditions of the chemical etchant were varied to assess their influence on the composite-to-metal tensile bond strength. Etched metal cylinders were bonded end-to-end with a resin luting agent and were subsequently tested for tensile strength. Etch patterns, mean bond strengths, and mode of failure were recorded. Significant differences relating to the application number and the thermal conditions of the chemically etched specimens were noted.   Malykhin, V. M. and G. F. Kovygin (1990). “The pattern design for evaluation of castability of nickel- chromium alloys.” Bull Tokyo Dent Coll31(2): 117-23. To find a pattern design that would provide a higher degree of discrimination for castability of nickel-chromium alloys using a polyester sieve cloth pattern, four shaped patterns were chosen. The results as calculated by t-test indicated that patterns No. 2 and No. 3 can discriminate the castability of nickel-chromium alloys over almost the total range of the casting temperatures, but that pattern No. 3 is a better discriminator for the castability. Pattern No. 1 can only discriminate the castability at lower casting temperatures. Pattern No. 4 can only discriminate the castability at higher casting temperatures. The percent castability value calculated from the number of complete square segments and the areas of the four patterns are highly linear correlations, so it is reasonably accurate to calculate the castability only from counting the number of complete square segments. Beryllium-containing nickel-chromium alloy is more castable than non-beryllium-containing alloy and the higher casting temperatures appear to result in better castability.   Nickles, R. J., A. A. Kulago, et al. (1990). “The effect of three different surface treatments on the tensile strength of the resin bond to nickel-chromium-beryllium alloy.” J Prosthet Dent 63(1): 4-8. The effect of three different metal surface treatments on the tensile strength of the resin bond to non-noble nickel-chromium-beryllium alloy was studied by bonding metal to metal. Chemical etching of the metal for 1 hour obtained the highest strength, followed by air-abraded bond specimens. Lowest strength was obtained with the gel- etch method. All resulted in clinically acceptable values.   (1991). “[Metals and alloys--corrosion, toxicology, and sensitivity reactions 2].” Zwr 100(6): 398-402.   Fukuda, J. and K. Kawa (1991). “[Metals and alloys--corrosion, toxicology, sensitivity reactions 1].” Zwr 100(5): 300-4, 307. Alloys used in dentistry should not compromise the health of patients and of dental personal. All aspects of biocompatibility, such as corrosion, toxicity and allergic sensitization should be considered when base metal alloys or low gold alloys are used. In regard to health legislation, alloys should considered to be 'drugs'. Hazardous alloys should not be recommended, if the primary concern is cost. However, there is no or only little evidence to show, that either of the alloy systems used would rise health risks, exempting the beryllium containing alloys. They should not be used any longer. Probably, dental technicians are endangered by beryllium more than patients are. Some of the Ni-Cr- alloys were shown to corrode. There is less evidence of allergic senzitization caused by nickelcontaining dental alloys, than suspected first.   Gettleman, L. (1991). “Noble alloys in dentistry.” Curr Opin Dent1(2): 218-21. Noble metals used for dental castings continue to consist of alloys of gold, palladium, and silver (not a noble metal) , with smaller amounts of iridium, ruthenium, and platinum. The majority are used as a backing for ceramic baking, with the rest used as inlays, onlays, and unveneered crowns. Base metal alloys, principally made of nickel, chromium, and beryllium have gained widespread usage, especially in the United States, due to their lower cost and higher mechanical properties. The current literature, for the most part, cites the use of noble alloys as controls for trials of alternative materials. Direct gold (gold foil) still retains a following and a number of new patents were founded.   Harrison, G. H. and E. K. Balcer Kubiczek (1991). “The effect of oxidation heat treatment of porcelain bond strength in selected base metal alloys.” J Prosthet Dent 66(4): 439-44. Base metal alloys have been widely used for fixed partial dentures in the past decade. The oxidation heat treatment (degassing) of these alloys is a controversial step to prepare the metal surface for bonding porcelain. This study evaluated the effect of oxidation heat treatment on the porcelain bond strength of base metal alloys and investigated composition changes that may have occurred during this process.   Johnsen, S. W. (1991). “Castability of various non-precious alloys. A comparative study.” J Indian Dent Assoc 62(3): 60-1, 63.   Lawson, J. R. (1991). “Alternative alloys for resin-bonded retainers.” J Prosthet Dent 65(1): 97-9. Traditionally, resin-bonded fixed partial dentures have been made with nickel-chrome-beryllium alloys and cemented with conventional resin luting cements. However, alternative alloys for resin-bonded retainers offer improved physical and biocompatible properties, and resin-metal bond strengths twice that of traditional methods can be achieved. The superior bonds obtained with etched base metals bonded with adhesive resins and silica-coated alloys bonded with silane-coupling agents make these the most desirable techniques available.   Louly, A. C., A. F. Mora, et al. (1991). “Tensile strength of preceramic solder joints formed using an infrared heat source.” Int J Prosthodont4(5): 425-31. Infrared soldering was compared to gas-oxygen torch soldering by testing specimens made from each of the following four classes of metal ceramic alloys: gold-platinum-palladium, gold-palladium, palladium-silver, and nickel-chromium-beryllium. There was no significant difference between infrared and torch soldering for the gold-palladium, palladium-silver, and base metal alloy specimens. However, infrared soldering of the gold-platinum-palladium alloy samples produced significantly weaker joints than those produced by torch soldering.   Saxén, L. and M. Pasila (1991). “Ulcerative lesions of the palate associated with removable partial denture castings.” J Prosthet Dent66(2): 213-21. Regions of inflammation with or without ulceration beneath removable partial dentures have been of concern to prosthodontists for many years. The etiology of these lesions has not been established, but potential factors are microbial infection, obstructive sialadenitis, and allergic-type reactions to the metal framework. A new etiological factor that may be involved is described. Focal pitting corrosion and by- products of corrosion in nickel-chromium alloys are discussed as toxic agents responsible for palatal lesions. Six patient reports that include results of tissue biopsy and EDAX analysis of casting are presented.   Fodor, I. (1992). “Leaching of nickel, chromium, and beryllium ions from base metal alloy in an artificial oral environment.” J Prosthet Dent68(4): 692-7. The use of base metal alloys in dentistry has gained wide popularity in recent years. However, claims of their safety have not been universally accepted. An artificial oral environment capable of reproducing three-dimensional force- movement cycles of human mastication was used to determine whether nickel, chromium, and beryllium ions were leached from base metal alloy. Twelve pairs of crowns were articulated in the following combinations: metal versus metal, metal versus enamel, metal versus porcelain, and metal versus metal without chewing as a control. In a simulated 1-year period of mastication, the results showed that nickel and beryllium metals were released both by dissolution and occlusal wear. These findings suggest that if these conditions occur in the oral cavity, the stability of base-metal alloys is subject to question. Further studies are needed to determine whether the leaching reported has long-term consequences for patients receiving base metal restorations.   Kasahara, M. (1992). “Shear bond strengths of prosthodontic adhesive systems to a nickel-chromium-beryllium alloy.” Quintessence Int 23(1): 65-9. Panavia, a composite resin luting agent containing phosphate monomers, bonds chemically to air-abraded base metal alloys and is particularly suited for cementing resin-bonded retainers. Another adhesive methodology (Silicoater system) incorporates a pyrolytically applied silica layer to metal substrates to promote bonding of a resin adhesive. The object of this study was to compare prosthodontic adhesive systems that incorporated the Silicoater system and/or Panavia. The results showed that the surface treatment that provided significantly higher shear bond strengths was the Silicoater system and a layer of unfilled resin. A second test evaluated use of Panavia as a metal opaquing material beneath laboratory light-curing resins. Results showed that Panavia Opaque material was displaced peripherally during placement of overlying laboratory composite resin veneers. This resulted in an uneven intermediate layer of Panavia.   Kolodney, H., A. D. Puckett, et al. (1992). “Shear strength of laboratory-processed composite resins bonded to a silane-coated nickel-chromium-beryllium alloy.” J Prosthet Dent 67(3): 419-22. The shear bond strengths of three commercial laboratory curing composite resin veneers bonded to a nickel-chromium- beryllium alloy treated with the Silicoater system were evaluated. Two light-cured resins and one heat- and pressure- cured resin were evaluated. No statistically significant difference in bond strengths among the three resins was found. Microscopic analysis of the fracture surfaces indicated that all failures were complex and cohesive in nature within the resin and composite. On the basis of the shear bond strengths measured, any of the composite resin veneers tested appear to be clinically acceptable.   Levi Setti, R., J. P. Berry, et al. (1992). “Digital imaging techniques for dental alloy castability quantification.” J Oral Rehabil 19(3): 297-308. In this study, mesh monitors cast from experimental compositions of a Ni-Cr-Be alloy are evaluated by the application of image analysis techniques. Castability values obtained by this method are then contrasted with those from three commonly employed manual counting procedures. While castability values obtained by all methods reflect the effect of compositional variations, a comparison of results with respect to evaluation method indicates that the image analysis technique consistently yields higher castability values, especially evident in the poorly casting groups. The apparent explanation for these observed differences is that with imaging, segments that are partially cast to varying degrees are not arbitrarily eliminated from the data, as is the usual practice in manual counting methods; therefore, castability values obtained by using the imaging technique will very closely reflect an actual alloy volume of each cast monitor.   Snow, E. T. (1992). “[Experimental studies on the systemic toxicity of dental alloys free of precious metals].” Schweiz Monatsschr Zahnmed102(7): 818-27. The systemic toxicity of five non-precious dental alloys was evaluated by help of an animal study. The pulverized dental alloys, filled in gelatine capsules, were orally administered to laboratory rats using a special esophageal application device. For each alloy examined randomized groups of ten experimental animals and ten control animals were used. For a period of seven days the experimental animals received daily 1000 mg alloy powder per kilogram body-weight. The animals of the control groups received daily empty gelatine capsules (placebo application). After two weeks all animals were killed and autopsies of the animals were performed. Histopathologic examinations of the lungs, kidneys, liver, small intestine and large intestine of all animals were done. With statistic significance ( p less than 0.001) rats whom nickel-chromium alloys were administered orally showed serious pathologic reactions more frequently than placebo-treated control animals. Nickel- chromium alloys containing beryllium and/or gallium caused the strongest organic lesions. In contrary to this a dental cobalt-chromium alloy showed a very low systemic toxicity. The results of the study underline that preclinical toxicity testing of dental alloys is necessary in order to avoid systemic toxic lesions in man.   Wienhold, K. (1992). “The base metal alloy question in removable partial dentures- -a review of the literature and a survey of alloys in use in Alberta.” J Can Dent Assoc 58(2): 146-51. Base metal alloys have been used for over 60 years to cast removable partial denture frameworks. Among other elements, these alloys principally contain nickel, chromium and cobalt, and may be divided into the nickel-containing and nickel- free alloys. Because of the potential biocompatibility hazard created by these and other elements found in the alloys, this group of materials has come under ever increasing scrutiny in the literature. This paper reviews pertinent literature and reports on the findings of a survey on the base metal alloys used in Alberta for the casting of removable partial denture frameworks.   Barnett, G. (1993). “Tensile fatigue of two composite cements bonding three base metal alloys to bovine enamel.” Dent Mater 9(1): 28-32. Tensile fatigue endurance limits were determined for three base metals (Ni-Cr, Ni-Cr-Be, and Co-Cr) bonded to bovine enamel using two composite cements: a Bis-GMA/phosphate ester composite cement which relies on a sand-blasted metal surface, and a Bis-GMA composite luting cement which relies on electrolytically etched metal surfaces. Samples were tested to failure or to 10(6) cycles at 5 hz in Ringer' s solution at 37 degrees C, and endurance limits were determined using a two-point test strategy. SEM evaluation was performed on fractured samples to determine failure mode. Statistical analysis of the results showed no difference between cements when using Ni-Cr-Be; however when using Co-Cr, the Bis- GMA/phosphate ester cement produced greater values than the Bis-GMA cement that relied on electrolytical etching. The opposite result occurred when a Ni-Cr alloy was tested with both cements. Evaluation of the results for each cement with the three different alloys showed statistical significant differences. SEM fracture analysis revealed a mixed failure pattern with apparent adhesive fracture from both the composite- enamel and composite-metal interfaces and cohesive failure throughout the cement.   Belinsky, S. A., D. S. Swafford, et al. (1993). “Bond strength of composite to alloy treated with bonding systems.” J Prosthodont 2(2): 110-4. PURPOSE: The in-vitro bond strengths of a composite bonded to a nickel-chromium-beryllium alloy treated by eight bonding systems were measured after three storage conditions. MATERIALS AND METHODS: Nickel-chromium-beryllium alloy samples were treated by eight commercial bonding systems including adhesive composite cements, all-purpose bonding agents, and silica- coating systems. A composite was bonded to the alloy samples. Sample groups were stored in water for 24 hours at 23 degrees C, or thermocycled, or stored for 6 months at 23 degrees C and then debonded in tension. RESULTS: Bond strengths after 24 hours storage were: adhesive composite cements, 14.2 to 22.1 MPa; all-purpose bonding agents, 11.4 to 14. 6 MPa; and silica-coating systems, 18.6 to 20.2 MPa. Bond strengths after thermocycling were: adhesive composite cements, 12.6 to 20.6 MPa; all-purpose bonding agents, 9.9 to 17.7 MPa; and silica-coating systems, 11.1 to 19. 2 MPa. Bond strengths after 6 months were: adhesive composite cements, 12.0 to 13.1 MPa; all-purpose bonding agents, 8.7 to 14.1 MPa; and silica-coating systems, 14.8 to 18. 4 MPa. CONCLUSIONS: Only two bonding systems showed decreased bond strength after thermocycling, as compared with 24 hours' storage; whereas four bond systems showed decreased bond strength after 6 months' storage. Bond strengths measured after thermocycling were not predictive of those measured after 6 months' storage.   Bumgardner JD, Lucas LC (1993). “Surface analysis of nickel-chromium dental alloys.” Dent Mater 9(4): 252-9.    Davila, C. E., A. G. Farman, et al. (1993). “RadioVisioGraphy of the temporomandibular joint: comparisons with transcranial radiography.” Cranio 11(4): 256-9. RadioVisioGraphy (RVG), a new digital imaging technique, is compared to conventional transcranial radiographic imaging of the temporomandibular joint. The results of this study using fixed human cadaver specimens revealed an excellent correlation between the recorded images and the actual anatomic specimens. Dosimetry, using a beryllium-windowed ionization chamber, showed a 64% dose reduction with charge- coupled device (CCD) when compared to standard film-screen combination.   Geis Gerstorfer, J. and K. Pässler (1993). “Studies on the influence of Be content on the corrosion behavior and mechanical properties of Ni-25Cr-10Mo alloys.” Dent Mater 9(3): 177-81. The influence of Be content on the corrosion behavior and strength of dental alloys was examined using experimental Ni-25Cr-10Mo-xBe alloys with graduated Be contents of 0, 0.6, 1.1, 1.6, and 2.1 wt.%. It became evident that the corrosion resistance is reduced even by a 0.6 wt.% Be content. Strength increases by 51% with increasing Be content, while ductility is reduced by 84%. The results revealed that, from the stand-point of corrosion resistance, Be-free Ni- Cr-Mo alloys should be preferred in clinical use.   Kotloff, R. M., P. S. Richman, et al. (1993). “Chronic beryllium disease in a dental laboratory technician.” Am Rev Respir Dis 147(1): 205-7. Workers involved in the manufacture of dental prostheses are exposed to a number of potentially harmful substances capable of inducing lung disease. In this report, we describe a dental laboratory technician who developed chronic beryllium disease as a result of exposure in the workplace. The diagnosis of chronic beryllium disease was suspected from the clinical, radiographic, and histologic features and confirmed by the in vitro proliferation of lung lymphocytes to beryllium salts. The potential risks of beryllium use in the dental industry have been recognized for some time, but this is the first documentation of chronic beryllium disease in this population of workers. Since chronic beryllium disease may be easily confused with sarcoidosis, awareness of this occupational association is essential in preventing misdiagnosis and in providing appropriate management.   Kuang, B. and P. A. Rubenstein (1993). “Contact dermatitis from beryllium in dental alloys [published erratum appears in Contact Dermatitis 1993 Oct;29(4):222].” Contact Dermatitis 28(3): 157-62. An increasing number of metals with the potential to cause allergic contact dermatitis have found their way into dental alloys for economic and practical reasons. 2 patients are reported who developed gingivitis adjacent to the Rexillium III alloy in their dental prostheses. Patch testing demonstrated positive reactions to beryllium sulfate, a component of the alloy. Components of dental alloys and the mechanism of the contact dermatitis are discussed.   Smith, R. M., M. G. Barrett, et al. (1993). “Effect of environmental stress and surface treatment on resin-to-metal bonding.” Am J Dent 6(3): 111-5. This study compares the bond strength and durability of three metal surface treatments subjected to two types of environmental stress for both short- and long-term exposures. The luting resins Panavia and Comspan were applied to alumina- blasted, non-beryllium, nickel-chromium alloy coupons. Metal surface treatments consisted of either microscopic roughening by electrochemical etching, or one of two types of adhesives: a silanated silica coating (Silicoating) or a phosphate ester monomer (a component in the Panavia liquid). Shear bond strength was determined following short- or long-term exposure to either thermocycling in 6-60 degrees C water (2,672 cycles/7 days or 10,584 cycles/42 days) or storage in 37 degrees C water (7 or 42 days). Three- way ANOVA showed that both the type of environmental stress and the exposure time affected the bond strength of electroetched surfaces, but that only exposure time affected the two chemical adhesives (P < 0.05), regardless of the environmental stress used. In the short-term, the silica/silane coated surfaces produced and maintained the higher shear bond strengths (15.9 +/- 2.3 MPa). However, after 42 days the silica/silane bonds decreased 30% (to 11.3 +/- 2.2 MPa) , while the phosphate ester bonds were essentially unchanged (11.4 +/- 3.0 at 4 days, 10.4 +/- 2.2 MPa at 42 days). Electroetched bonds were the weakest and decreased by 18% between 7 and 42 days in water (8.8 +/- 1.2 to 7.2 +/- 3.0 MPa) and 27% after 42 days of thermocycling (7.2 +/ - 2.8 to 5.3 +/- 1.8 MPa).   (1994). “Comparison of shear bond strengths of two resin luting systems for a base and a high noble metal alloy bonded to enamel.” J Prosthet Dent 72(5): 457-61. Researchers are investigating the use of noble metals for the fabrication of resin-bonded prostheses because of concerns about health hazards of nickel and beryllium in base metal alloys. Tin-plating has been advocated to improve the bond of resin luting agents to noble metal alloys. Some manufacturers have suggested that tin-plating is unnecessary to bond noble metal alloys to etched enamel with their products. In this study, Rexillium base metal and Olympia noble metal alloy specimens were bonded to extracted human teeth with the use of two resin luting agents (F21 and Panavia OP) . One third of the noble metal specimens were tin-plated, one third were oxidized, and one third were oxidized and sandblasted. Each of the bonded specimens were thermocycled and subjected to a shear force until bond failure. The base metal specimens bonded with Panavia OP luting agent exhibited the greatest mean shear bond strengths. The tin- plating surface treatment significantly increased the mean shear bond strengths of Olympia noble metal specimens.   Kern, M. and V. P. Thompson (1994). “Influence of prolonged thermal cycling and water storage on the tensile bond strength of composite to NiCr alloy.” Dent Mater 10(1): 19-25. OBJECTIVES. The purpose of this study was to evaluate the bond strength and bond durability of new adhesive systems (both micromechanical and chemo-mechanical) to a beryllium- free nickel-chromium alloy (NiCr). METHODS. Plexiglass tubes filled with composite were bonded to NiCr alloy discs. Groups of 24 samples were bonded using six different bonding systems. Subgroups of eight bonded samples were stored in an isotonic artificial saliva solution (37 degrees C) either for 1 d, 30 d or 150 d. In addition, the 30 and 150 d samples were thermal cycled for 7,500 or 37,500 cycles, respectively. RESULTS. The bond strength of a conventional BisGMA composite to sandblasted NiCr was statistically significantly lower than that of chemo-mechanical bonding systems and decreased continuously during the storage time of 150 d. The additional use of a silane on the sandblasted alloy resulted only in a slight, statistically insignificant increase in bond strength. Statistically significantly higher and more durable bonds to NiCr alloy were achieved either with the combination of silica coating and use of a conventional BisGMA composite or with the combination of sandblasting and the use of a composite modified with a phosphate monomer. In these systems, the bond strengths were limited by the cohesive strength of the resin composites. However, a newly developed composite containing the same active phosphate monomer showed a statistically significant decrease in bond strength (cohesive strength) over storage time. SIGNIFICANCE. Longer-term storage times in a wet environment are needed in laboratory tests to examine the durability of bonding systems.   Mark, G. J., C. B. Monroe, et al. (1994). “Bond strength of adhesive composites to dental substrates.” J Prosthodont 3(3): 126-9. PURPOSE: The purpose of this study was to evaluate the in vitro bond strength of adhesive and traditional composites to several materials that might be encountered in clinical practice. MATERIALS AND METHODS: An adhesive composite, an adhesive composite with a bonding agent, and a traditional composite with a bonding agent were bonded to enamel, dentin, amalgam, porcelain, and nickel-chromium-beryllium (Ni-Cr- Be) alloy. Tensile bond strengths were determined after 24 hours storage at 23 degrees C or thermocycling. RESULTS: The use of an adhesive composite with a bonding agent resulted in increased bond strength to amalgam, porcelain, and dentin, but not to enamel or Ni-Cr-Be alloy at 23 degrees C, when compared with the adhesive composite alone. The adhesive composite with a bonding agent had higher bond strengths to amalgam, porcelain, and dentin than did the traditional composite with bonding agent, but not to enamel or Ni-Cr- Be alloy at 23 degrees C. CONCLUSIONS: The use of a bonding agent with an adhesive composite produced higher bond strengths than the adhesive composite alone. The traditional composite bonded better to enamel and Ni-Cr-Be alloy than did the adhesive composite. Thermocycling generally had no effect on bond strengths or increased them slightly.   Moschcovich, L., Y. M. Peyser, et al. (1994). “Chemical etching solutions for creating micromechanical retention in resin-bonded retainers.” J Prosthet Dent 71(3): 303-9. This study introduced three chemical etching solutions capable of producing micromechanical retention in nickel- chromium and nickel-chromium-beryllium alloys used for resin-bonded retainers. The effectiveness of the chemical etching solutions was evaluated with tensile strength tests and photographs at various magnifications with a scanning electron microscope. Chemical etching with the CG-Etch solution produced suitable and uniform microretention whereas the other solutions were not effective on all metal alloys. Significant differences (p < 0.05) relating to tensile bond strengths were noted. The CG-Etch solution gave the highest mean bond strength compared with solutions II, III, and control groups.   Vilaplana, J., C. Romaguera, et al. (1994). “Contact dermatitis and adverse oral mucous membrane reactions related to the use of dental prostheses.” Contact Dermatitis 30(2): 80-4. The latest trends in the use and composition of dental prostheses have been reviewed, and 66 patients referred by dermatologists and odontologists patch tested. The allergen series used were: TRUE Test standard series; Chemotechnique dental screening series; specially prepared metals series. The allergens found to be positive, in order of frequency, were: nickel, cobalt, potassium dichromate, rhodium, palladium, mercury, beryllium, methyl methacrylate, copper and zinc.   Atta, O. M., I. E. Mosleh, et al. (1995). “Chemical etching and EDAX analysis of beryllium-free nickel- chromium ceramo-metal alloy.” Egypt Dent J41(4): 1391-5. A chemical etching technique is described for producing etch patterns in beryllium-free nickel chromium ceramo- metal alloy. Disc-shaped samples were chemically etched, evaluated with SEM and analysed by the EDAX technique. Scanning electron micrographs revealed, profound retentive cavities. The EDAX analysis provided a comprehensive interpretation of the etch mechanism. The obtained results show that the developed chemical etching has the potential to produce a highly retentive etched surface with less problematic and less technique sensitive than electrolytic etching.   Bigay, J., P. Deterre, et al. (1995). “Cellular response to metallic ions released from nickel- chromium dental alloys.” J Dent Res 74(8): 1521-7. Concerns exist over the potential release of elevated levels of metal ions such as Ni and Be from Ni-Cr dental casting alloys, due to their susceptibility to accelerated corrosion. In this investigation, we evaluated the release of metal ions from four commercial Ni-Cr alloys, representing a range of compositions, in three-day cell culture tests. Metal ion release, as measured by atomic absorption spectroscopy, was correlated to changes in cellular morphology, viability, and proliferation. The results showed that the test alloys and their corrosion products did not affect cellular morphology or viabilities, but did decrease cellular proliferation. The types and amounts of metal ions released, which corresponded to the alloys' reported surface and corrosion properties, also correlated to observed decreases in cellular proliferation after 72 h. Neptune, which caused the smallest decrease in cellular proliferation as compared with control cells, released the lowest amount of corrosion products, due to its corrosion-resistant, high-Cr-Mo-containing, homogeneous surface oxide. The other test alloys, which were susceptible to accelerated corrosion processes, released higher levels of metal ions that correlated to larger decreases in thymidine incorporation. Metal ion levels increased with test time for all alloys but were not proportional to bulk alloy compositions. Ni ions were released at slightly higher than bulk alloy compositions, while Be was released at from four to six times that of bulk alloy compositions. The elevated release of Be ions was associated with reduced cellular proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)   Bresnitz, E. A. and B. L. Strom (1995). “Tensile bond strength of a composite resin cement for bonded prosthesis to various dental alloys.” J Prosthet Dent 74(3): 230-4. The development of composite resin cements that chemically bond to dental alloys has improved the construction of resin-bonded prostheses. Composite resins can be selected for various situations, but specific clinical situations may require different alloys. This study evaluated the ability of a composite resin cement to bond to various dental alloys of different compositions. Ten pairs of disks for each alloy (two NiCr, two NiCrBe, one CuAl, one gold type IV, and one gold for metal ceramic) were bonded to a composite resin cement after air abrasion was performed with aluminum oxide. The disks were then rinsed in tap water and were ultrasonically cleaned in distilled water for 2 minutes. The tensile tests exhibited greater values for alloys ultrasonically cleaned, and the best results were recorded by NiCr and NiCrBe alloys.   Bumgardner, J. D., J. Doeller, et al. (1995). “Effect of nickel-based dental casting alloys on fibroblast metabolism and ultrastructural organization.” J Biomed Mater Res 29(5): 611-7. Previous cell culture evaluations have shown that nickel- chromium dental alloys did not affect cellular viability or morphology. However, nickel-based alloys released corrosion products which decreased cellular proliferation. It was hypothesized that this decrease was due to an interference of cellular energy metabolism by released metal ions. To test this hypothesis, we evaluated the effects on cellular energy metabolism, adenosine triphosphate (ATP) levels, and cellular ultrastructure by four nickel-based alloys, including high and low chromium alloys with and without beryllium additions, in human gingival fibroblast cell cultures. Energy metabolism was evaluated by measuring glucose-6-phosphate dehydrogenase (G-6-PDH) activity. ATP levels were measured with the luciferin-luciferase method. Cellular membranes and ultrastructural organization were evaluated by scanning and transmission electron microscopy. The results of this study showed that metal ions released from all alloys completely inhibited G-6-PDH activity and reduced cellular ATP levels as compared to controls. The reduction in intracellular ATP was greater for the beryllium containing alloys than the non-beryllium-containing alloys. However, no morphologic changes in cellular membranes or organelles were observed. These results support the hypothesis that metal ions released from nickel-based dental casting alloys interfere with cellular energy metabolism.   Ferencz, J. L. (1995). “Porphyromonas gingivalis lipopolysaccharide affinity for two casting alloys.” J Prosthet Dent 74(1): 33-8. With the exception of plaque, the affinity of biologically active bacterial products for restorative materials and the influence of that affinity on periodontal health has not been detailed. This study recognized that Porphyromonas gingivalis endotoxin, which is cell envelope lipopolysaccharide (LPS) produced by a bacterium that is common to the crevicular microbial flora, has an affinity for dental casting alloys. Regardless of surface finish, no difference in LPS initial adherence or elution was recorded between a type III gold or nickel-chromium-beryllium alloy (p > 0.05), but LPS readily adhered and remained attached to both alloys. LPS affinity could contribute to periodontal inflammation in tissues that approximate restorations fabricated from either alloy.   Prunescu, C. C., P. Prunescu, et al. (1995). “Bond strength of an adhesive resin system with various dental substrates.” J Prosthet Dent 74(5): 463-8. A laboratory study was conducted to evaluate the Panavia 21 resin-based adhesive system as a bonding agent between a variety of dental substrates. Panavia 21 resin was bonded directly to enamel and dentin and placed between nickel- chromium-beryllium (Ni-Cr-Be) specimens and enamel, dentin, other Ni-Cr-Be samples, and type III gold. Panavia 21 resin was also used to bond amalgam to dentin. Shear bond strengths were determined at 24 hours and after thermocycling at 3 months. The results of this study at both the 24-hour and the 3-months test periods indicate that the enamel bond strengths of Panavia 21 resin (24 hours, 19.3 +/- 5.5 MPa; 3 months, 23.7 +/- 4.4 MPa) exceeded its dentin bond strengths (24 hours, 7.8 +/- 1.4 MPa; 3 months, 8. 8 +/- 3.2 MPa). The bond strengths between Panavia 21 resin and Ni-Cr-Be alloy (24 hours, 16.3 +/- 3.4 MPa; 3 months, 17.6 +/- 2.7 MPa) and those for Panavia 21 resin between Ni-Cr-Be alloy and dentin (24 hours, 18.7 +/- 4.2 MPa; 3 months, 19.8 +/- 5.3 MPa) were comparable to adhesive enamel bond strengths. High bond strengths were also generated by Panavia 21 resin between Ni-Cr-Be alloy and type III gold (24 hours, 39.3 +/- 5.9 MPa; 3 months, 35.5 +/- 7. 1 MPa). The greatest bond strengths observed during both test time periods for Panavia 21 resin were between Ni- Cr-Be alloy and enamel (24 hours, 54.2 +/- 10.7 MPa; 3 months, 56.4 +/- 7.1 MPa) and between two samples of Ni- Cr-Be alloy (24 hours, 55.1 +/- 5.6 MPa; 3 months, 49.1 +/- 8.6 MPa). Panavia 21 resin produced high bond strengths between a variety of dental substrates commonly used for the placement of fixed prosthodontic restorations.   Seko, Y., T. Koyama, et al. (1995). “Shear bond strength of composite resin to microetched metal with five newer-generation bonding agents.” Oper Dent 20(2): 58-62. The purpose of this study was to determine the shear bond strength of a hybrid composite resin to a nickel-chrome- beryllium (Ni-Cr-Be) alloy, using five of the newer-generation bonding agents: Optibond, All-Bond 2, Prisma Universal Bond 3, Restobond 4, and Amalgambond Plus with HPA. For each bonding system 10 samples of metal were microetched with 50-micron aluminum oxide prior to the placement of the bonding agent and resin. The shear bond strength was tested, and the results showed that Amalgambond Plus with HPA developed the strongest bond at 18.81 +/- 3.924 MPa, followed by All-Bond 2 at 14.33 +/- 3.408, Optibond at 13.97 +/- 1.508, Prisma Universal Bond 3 at 12.51 +/- 1. 845, and Restobond 4 at 10.29 +/- 1.407.   Thompson, V. P., E. Del Castillo, et al. (1995). “Durability of resin bonds to a cobalt-chromium alloy.” J Dent 23(1): 47-54. Common nickel-chromium-beryllium alloys used for resin- bonded fixed partial dentures have possible health hazards due to leaching of nickel and beryllium. For resin-bonded restorations corrosion resistant cobalt-chromium alloys (CoCr) are a suitable alternative material without sacrificing physical properties. This study evaluated the bond strength and bond durability of new adhesive systems to a CoCr alloy. Plexiglas (acrylic) tubes filled with composite were bonded to CoCr alloy discs. Groups of 24 samples were bonded using six different bonding systems. Subgroups of eight bonded samples were stored in an isotonic artificial saliva solution (37 degrees C) either for 1 day, 30 days or 150 days. In addition the 30- and 150-days samples were subjected to 7500 or 37,500 thermal cycles, respectively. The bond strength of a conventional BisGMA composite (Twinlook) to sandblasted CoCr was significant lower than when using chemomechanical bonding systems and decreased continuously during the storage time of 150 days. The additional use of silane on the sandblasted alloy resulted in an insignificant increase in bond strength. Statistically significant higher and more durable bonds to CoCr alloy were achieved either with the combination of silica coating and use of the conventional BisGMA composite or with the combination of sandblasting and the use of a composite modified with a phosphate monomer (Panavia EX). In the latter systems, the bond strengths were mainly limited by the cohesive strength of the resin composites: partial adhesive failures were only observed for a tribochemical silica coating system. A new composite also containing the active phosphate monomer (Panavia TPN-S) exhibited a significant decrease in cohesive strength over time.   Adachi, S. and K. Takemoto (1996). “Sensitometric response of the Sens-A-Ray, a charge-coupled imaging device, to changes in beam energy.” Dentomaxillofac Radiol 25(1): 17-8. OBJECTIVES: To evaluate image density (pixel values) and image contrast due to variations in beam energy (kVp) for the Sens-A-Ray intra-oral radiographic sensor. METHOD: Images of an aluminium step wedge were made at 50, 70 and 90 kVp. Mean pixel values (with standard deviations) for representative attenuator thicknesses were measured using region-of-interest histogram analysis. Corresponding entrance doses were measured using a beryllium-windowed ionization chamber. RESULTS: The steepest response slopes were found with the lowest kVp settings; hence the CCD results mimic the behaviour of standard radiographic film, with the high contrast being found with low kVp. The entrance dose resulting in pixel saturation was less with low kVp than high kVp. It is suggested that this is due to the CCD receptor being most sensitive to X-ray photons of relatively low keV. CONCLUSION: While the kVp needs to be selected in relation to both tissue and receptor characteristics, it is possible to use low kVp techniques with the Sens-A-Ray without increasing the entrance dosage.   Epstein, W. L. and V. S. Byers (1996). “Castability, opaque masking, and porcelain bonding of 17 porcelain-fused-to-metal alloys.” J Prosthet Dent 75(4): 367-74. Seventeen porcelain-fused-to-metal alloys, which represented a cross section of the various alloy types available, were evaluated for castability, opaque masking, and porcelain bond strength. The base metal alloys generally cast more completely than the noble alloys, with the presence of beryllium as an important factor for greater castability among the base metal alloys. Statistically significant differences were observed in the ability of an opaque porcelain to mask the different alloy substrates but no systematic effect of alloy type was observed. Porcelain bond testing revealed that nickel-chromium-beryllium alloys produced significantly better porcelain-metal bonds than nickel- chromium alloys without beryllium. In addition, it was found that palladium-copper alloys produced significantly better bonds with porcelain than palladium-cobalt alloys.   Wang, C. C. and C. S. Hsu (1996). “[The bonding mechanisms of base metals for metal-ceramic crown microstructure analysis of bonding agent and gold bond between porcelain and base metals].” Kao Hsiung I Hsueh Ko Hsueh Tsa Chih 12(6): 326-38. The use of base metal alloys for porcelain fused to a metal crown and bridges has increased recently because of lower price, high hardness, high tensile strength and high elastic modulus. The addition of beryllium to base metal alloys increased fluidity and improved casting fitness. Beryllium also controlled surface oxidation and bonding strength. The bonding agent and gold bonding agent also affected the bonding strength between porcelain and metal alloys. Four commercially available ceramic base alloys were studied (two alloys contained beryllium element, another two did not). The purpose of this investigation was to study the microstructure between porcelain matrix, bonding agent and alloy matrix interfaces. A scanning electron micro- probe analyzer and energy dispersive X-ray spectroscopy (EDXS) were used to study the distribution of elements (Ni, Cr, Mo, Cu, O, Si, Sn, Al) in four base alloys. The following results were obtained: 1. The thickness of the oxidized layer of Rexillium III alloy and Unitbond alloy (contained beryllium) was thinner than Unibond alloy and Wiron 88 alloy (no beryllium). 2. The thickness of the oxidized layer of alloys in air (10 minutes and 30 minutes) was thinner in Unitbond (2.45 microns and 3.80 microns) and thicker in Wiron 88 (4.39 microns and 5.96 microns) . 3. The thickness of the oxidized layer occurring for a duration of ten minutes (in vaccum) showed that the Rexillium III alloy was the thinnest (1.93 microns), and Wiron 88 alloy was the thickest (2.30 microns). But in thirty minutes (vacuum), Unitbond alloy was the thinnest (3.37 microns) , and Wiron 88 alloy was the thickest (5.51 microns). 4. The intensity of Cr elements was increased obviously near the interface between Unitbond alloy, Wiron 88 alloy (no beryllium) and oxidized layer, but the intensity of Ni and Mo elements was slightly increased. The intensity of Cr element was not increased markedly between Rexillium III alloy, Unitbond alloy (beryllium) and oxidized layer. 5. A white-grayish oxidized layer appeared at the metal- ceramic interfaces but the thickness of oxidized layer was not obviously different. 6. The use of bonding agent at metal-ceramic interface leads to the deposition of many Sn elements at about 40 microns range within the porcelain surface. 7. Second interaction phases at the porcelain layer appeared when gold bonding agent was used, and a 50-100 microns microleakage occurred at the metal-ceramic interface.   Wu, Y. T. and C. S. Hsu (1996). “[The shear bond strength of porcelain and base metal alloys for metal-ceramic crown the study of metal roughness and microstructure].” Kao Hsiung I Hsueh Ko Hsueh Tsa Chih 12(12): 728-36. The metal-ceramic crown has become a predominant restoration in fixed prosthodontics. The base metal has the quality of lower price, high tensile strength, high elastic modulus. The base metal alloy that contain beryllium element increases fluidity and improved casting performance. Beryllium also controls surface oxidation and affects the metal ceramic bonds. Preparation of surface prior to porcelain bonding has been a subject of controversy among dental ceramists. Two ceramic base metal alloys (one alloy contains beryllium, another is not) were studied. This investigation evaluated the polishing effects of 50 microns, 100 microns aluminum oxide sandblasting, carbide bur, carborundum point and separating disk upon two base metal alloys, Rexillium III and Wiron 88. A scanning electron microscope was used to study the surface texture. The following results were obtained: 1. The most roughest surface was created with 50 microns aluminum oxide sandblasting. The carbide bur produced the least roughed surface. 2. There are specific surface texture patterns after polishing with five different grinding materials. 3. The metal surfaces treated with 50 microns and 100 microns aluminum oxide have same micro-structure pictures, but there are much more undercuts treated with 100 microns aluminum oxide. 4. The usage of carbide bur resulted in less undercuts of metal surface at two metal alloys. 5. The usage of carborundum point and disk resulted in abrasive particles that retained on the grinding metal surface at two metal alloys. 6. The surface of Wiron 88 alloy usually had wrinkle texture but not the Rexillium III alloy.   Zissu, D., S. Binet, et al. (1996). “[Differential diagnosis of berylliosis/sarcoidosis in a dental technician].” Dtsch Med Wochenschr 121(47): 1462-6. HISTORY AND CLINICAL FINDINGS: Sarcoidosis was diagnosed in a dental technician when he was aged 21 years. Two years later prednisolone treatment was started and continued for 14 years because of nonproductive cough with progressive reduction in vital capacity and CO transfer capacity. Subsequently the risk of exposure to beryllium-containing dust in dental laboratories became known. In his case exposure had started before sarcoidosis had been diagnosed and had continued for 16 years. Changes typical of sarcoidosis (unproductive cough and dyspnoea; bihilar lymphadenopathy and reticulonodular marking in the chest radiogram) were now present, at the age of 40 years. INVESTIGATIONS: Vital and diffusion capacities were diminished, serum levels of angiotensin-converting enzyme (141 U/I) and of neopterin (5.8 mg/l) were increased. Beryllium-lymphocyte transformation test of peripheral mononuclear cells after invitro culture with beryllium sulphate gave a raised stimulation index, and the intracutaneous beryllium sensitisation test was positive. This indicated sensitisation to beryllium even 9 years after exposure had ceased. CONCLUSION: Even after exposure to beryllium has ended, proof of exposure together with clinical and radiological findings typical of sarcoidosis and beryllium sensitisation can provide the diagnosis of berylliosis.   Goldschmidt, H. (1997). “Comparison of bond strengths of denture base resins to nickel-chromium-beryllium removable partial denture alloy.” J Prosthet Dent 78(6): 566-73. PURPOSE: In vitro bond strengths of a traditional denture base resin (Lucitone 199) and three adhesive denture base resins (Meta-Dent, Meta-Fast with liner, and Meta-Fast without liner) to treated nickel-chromium-beryllium (Ni- Cr-Be) partial denture alloy were tested with four alloy surface pretreatments (sandblast, Met-etch, Rocatec with silane, and Rocatec without silane), with or without primer (Dentsply). The Lucitone 199 resin bonded to the nonprimed sandblasted group was the control group. The hypothesis was the use of alloy pretreatments and/or primer does not improve the bond strength of denture base resins to sandblasted Ni-Cr-Be partial denture alloy. MATERIAL AND METHODS: Primed and nonprimed bonded specimens were prepared and finished, stored in 37 degrees C distilled water for 24 hours, then debonded in tension on a testing machine. The bond strength was calculated in megapascals (MPa). Five specimens were prepared and tested for each experimental condition, both with and without primer, for a total of 160 specimens. RESULTS: For three-way analysis of variance, the main effects of resins and treatment were statistically significant (p < 0.05), but the main effect of primer was not statistically significantly (p > 0.05). Without primer, the control group had the lowest bond strength (0 MPa). The three adhesive resin groups produced significantly higher bond strengths than the Lucitone resin groups. For the treated groups, nearly all sandblasted groups produced significantly lower bond strength than the other three treated groups. Meta- Dent to Met-etch treated group had the highest bond strength (23.9 MPa). With primer, the bond strengths of the Lucitone resin groups were significantly higher than the nonprimed groups, and the Lucitone resin-primed Rocatec treated group had the highest bond strength (14.8 MPa). For the three adhesive denture base resins, nearly all primed treated groups had significantly lower bond strengths than nonprimed groups. CONCLUSIONS: Without primer, the Lucitone resin- sandblast treated group (control) had the lowest bond strength (0 MPa). The Meta-Dent denture base resin with the Met- etch treated group had the highest bond strength (23.9 MPa). With primer, the Lucitone resin-primed Rocatec-silane treated group had the highest bond strength (14.8 MPa). For the adhesive denture base resins, nearly all bond strengths of the primed treated groups were significantly lower than the values of the nonprimed groups.   Hsu, C. S. and C. C. Wang (1997). “[The shear bond strength of porcelain and base metal alloys for metal-ceramic crown (VI)].” Kao Hsiung I Hsueh Ko Hsueh Tsa Chih 13(12): 721-9. The popularity of base metal alloy for porcelain fused to a metal crown and bridges has increased recently because of lower price, superior yield strength and modulus of elasticity (rigidity). The use of these alloys give them the potential advantage of thinner coping with less material and the required rigidity for long-span fixed partial dentures. The addition of beryllium to base metal alloys increases fluidity and improves casting fit. Beryllium also controls surface oxidation and bonding strength. Oxidation heat treatment of the metal is used to remove entrapped air, eliminate organic material and form the metal oxidized layer. The bonding agent and gold bonding agent also affect the bonding strength between porcelain and metal alloys. Four commercially available ceramic base alloys (two alloys contain beryllium element, another two do not) are studied. The purposes of this investigation are to test the shear bond strength between porcelain and metal alloy under different conditions (oxidized layer removed or not, gold bonding agent and uniseal bonding agent used in combination, separately or not at all). The following results were obtained: 1. Whether the oxidized layer was removed or not did not have a significant effect on the bond strength of porcelain (p > 0.05). 2. When different metal alloys was used, Wiron 88 alloy showed significantly the best bond strength of all alloys tested (p < 0.05). 3. When different bonding agent were used, the combination of bonding agent and gold bonding agent showed the best bond strength of all bonding agents tested. It showed a significantly higher bonding strength than opaque layer and gold bonding agent. 4. Vita porcelain powder showed a significantly higher bond strength than did Unibond porcelain (p < 0.05). 5. When opaque layer was used and when no bonding agent was used, the porcelain powder significantly affected the bond strength (p < 0. 0001). The Vita porcelain showed a significantly higher bond strength than did Unibond porcelain. Wiron 88 alloy showed significantly the high bond strength than Rexillium III alloy (p < 0.05). 6. When bonding agent was used, the porcelain powder and alloy significantly affected bond strength. The Vita porcelian showed a significantly higher bond strength than did Unibond porcelain. Wiron 88 alloy showed significantly the best bond strength than other alloys Wiron (p < 0.05). 7. When bonding agent and gold bonding agent were used, the porcelain powder significantly affected the bond strength (p < 0.05). The Vita porcelain showed a significantly higher bond strength than did Unibond porcelain (p < 0.05). 8. When gold bonding agent was used, there was not any bond strength between metal and powder.   Hsu, C. S. and Y. T. Wu (1997). “[The shear bond strength of porcelain and base metal alloys for metal-ceramic crown (VII)].” Kao Hsiung I Hsueh Ko Hsueh Tsa Chih 13(12): 730-7. The popularity of the base metal alloys has increased in the past decade because of their lower price, high tensile strength and high elastic modulus. Several factors are critical in ensuring successful bonding: the matching of the thermal coefficients of expansion and constraction of the porcelain and metal, the metallurgic composition of the alloy and the pretreatment procedures used in preparation of the metal substructure. Two ceramic base alloys (one alloy contains beryllium, another without) were studied. The surface textures were created by 50 microns, 100 microns aluminum oxide sandblasting, carbide bur, carborundum point and disk upon two base alloys, Rexillium III and Wiron 88. The purposes of this investigation were to determine how these variations in surface texture affect the bond strength of the two ceramo-metal alloy systems. The following results were obtained: 1. Statistics revealed that bond strength was not significantly increased with surface roughness (p > 0.05). 2. The shear bond strength for variable pretreatment methods were in the following sequence: 100 microns Al2O3 sandblasting, carbide bur, 50 microns Al2O3 sandblasting, carborundum point, disk. 3. The Rexillium III alloy had a significantly higher bond strength than Wiron 88 alloy (p < 0.05). 4. The Noritake porcelain showed a significantly higher bond strength than Biobond porcelain (p < 0.05). 5. The fracture site was cohesive and adhesive mode treated with 50 microns Al2O3, 100 microns Al2O3, carbide bur. But carborundum point and disk was adhesive mode.   Leinfelder, K. F. (1997). “An evaluation of casting alloys used for restorative procedures [see comments].” J Am Dent Assoc 128(1): 37-45. Dental casting alloys have played a major role in the restorative process for three-quarters of a century. Gold-based compositions were used almost exclusively for most of that time-but because of their relatively high cost, they began to be replaced by a number of base metal alloys. This article discusses some of the most recent findings about the composition of alloy systems and the possible tissue responses to those systems.   Newman, L. S. (1997). “Casting alloys [letter; comment].” J Am Dent Assoc 128(5): 550.   Sprince, N. L., H. Kazemi, et al. (1997). “Effect of dental base metal alloys on IgE levels and some blood parameters.” J Oral Rehabil24(10): 749-54. Despite the widespread use of nickel-based alloys, claims for safety of these alloys have not yet been accepted universally. The allergenic effects of nickel on dental patients and the potential toxic effects of nickel and beryllium on laboratory technicians continue to cause concern within the dental profession. The purpose of this study was to investigate immunoglobulin type E (IgE) values and some blood parameters of dental laboratory technicians who use dental base metal alloys. The following two groups were studied: 19 students who had been working with dental base metal alloys for two years; and 21 pre-clinical students who had never worked with dental base metal alloys. The latter group were used as a control. Blood specimens were taken from both groups and analysed using The Blood Counter. Total erythrocyte, thrombocyte, leukocyte, lymphocyte, granulocyte and monocyte counts were determined. Measurement of IgE was made with Coat-A-Count Total IgE IRMA. Blood and IgE measurements were repeated after 8 months. In the experimental group both erythrocyte and thrombocyte values were found to be statistically significantly decreased compared with the control group. No significant differences were found in lymphocyte and monocyte numbers between the initial and later measurements. There were no significance changes in IgE values for both groups. These results provide no evidence that dental base metal alloys (Ni, Cr, Be, Co) caused an increase in sensitization, during the period of the study.   Bencko, V., M. Brezina, et al. (1998). “Effect of beryllium on the castability and resistance of ceramometal bonds in nickel-chromium alloys.” J Prosthet Dent 80(5): 570-4. STATEMENT OF PROBLEM: Castability and ceramometal bond resistance play an important role in accepting nickel-chromium alloys as a substitute for gold alloys in dentistry. PURPOSE: This study was developed to verify the effect of beryllium on these factors in several compositions of nickel-based alloys by submitting them to castability and ceramometal bonding resistance tests. MATERIAL AND METHODS: Three experimental compositions of Ni-Cr alloys with different amounts of beryllium were used. One beryllium-free alloy was used as the control. RESULTS: Analysis of variance and Tukey' s test showed significant differences (alpha = .001) for the castability test results and significant differences (alpha = .05) for ceramometal bond resistance between alloys. CONCLUSIONS: Although the amounts of chromium, manganese, and niobium were maintained, the variations in the amounts of beryllium allowed the estimation that Be-containing alloys presented better castability than Be-free alloys. The 0.9% Be-containing alloy demonstrated higher resistance of the ceramometal bond than the Be-free alloy.   Bingle, W. H., J. L. Doran, et al. (1998). “Lung granulomatosis in a dental technician.” Am J Ind Med 34(6): 628-31. BACKGROUND: Dental technicians are potentially exposed to various occupational dusts and chemicals. Not surprisingly, occupational related lung diseases have been documented in this population. METHODS: We describe the case of a dental laboratory technician presenting progressive exertional dyspnea and cough. We used lung function tests, computed tomography, histological examination, mineralogical and immunological studies to characterize his condition. RESULTS: Lung function studies disclosed a restrictive pattern with a low diffusion capacity. A high-resolution CT scan revealed the presence of micronodules in both lungs corresponding to non-caseating foreign body granulomas at histological examination. Mineralogic studies showed the presence of silica, silicates, and aluminum. The lymphocytic transformation test was positive with the bronchoalveolar lavage for beryllium. CONCLUSIONS: This dental technician developed pulmonary granulomatosis. Combined histological, mineralogical, and immunological studies led us to consider the diagnosis of pneumoconiosis most likely related to occupational exposure to beryllium and aluminum.   Farman, A. G. and T. T. Farman (1998). “Panoramic dental radiography using a charge-coupled device receptor.” J Digit Imaging 11(3 Suppl 1): 166-8. Panoramic radiography using a slit beam and film/screen receptor is standard for the emergency room evaluation of mandibular fractures and also in dentistry. This study compared the spatial resolution, area distortion factors, and the dosage considerations for a panoramic system where standard film/screen and a charge-coupled device were alternatively employed as the image receptor. Resolution and image contours were determined using a lead resolution grid positioned at selected beam projection angulations. Exposure measurements were carried out using a RANDO average man phantom and a 3 cc beryllium-windowed ionization chamber. The maximum spatial resolution with film approached 5 lp mm-1 whereas with the CCD the maximum resolution was just above 4 lp mm-1. Consequently, the image layer was reduced slightly in width when using the CCD receptor. The use of the CCD resulted in skin exposure reduction exceeding 70%.   NaBadalung, D. P., J. M. Powers, et al. (1998). “Comparison of bond strengths of three denture base resins to treated nickel-chromium-beryllium alloy.” J Prosthet Dent 80(3): 354-61. PURPOSE: In-vitro bond strengths of 3 denture base resins (Trutone, Lucitone 199, and Triad) to a nickel-chromium- beryllium removable partial denture alloy (Ticonium) were tested with 3 surface pretreatments: sandblast, acid etch, and Rocatec (silica blasting), with or without primers (Dentsply, CR inlay cement, and Super Bond). MATERIAL AND METHODS: Lucitone 199 denture base resin bonded to the nonprimed sandblasted alloy specimen served as the control group. Alloy specimens were prepared, surface treated, and primed or not primed with primer. The treated specimens were then packed and processed with the denture base resin. Bonded specimens were stored in the distilled water at 37 degrees C for 24 hours, and then debonded in tension. The force at which the bond failed was noted, and bond strength was calculated in megapascals (MPa). Five replications for each condition (180 specimens total) were tested. RESULTS: Significant differences in bond strength were observed with primer, the most important factor, followed by pretreatment and denture base resin. Without primer for all 3 denture base resins, the Met-Etch and Rocatec treated group showed significantly higher bond strengths than the sandblasted groups. For Trutone denture base resin, nonprimed treated groups produced significantly higher bond strength than those for the other 2 denture base resin, nonprimed treated groups produced significantly higher bond strength than those for the other 2 denture base resins. The control group had zero bond strength. For Dentsply primer, the Rocatec treated group bonded to Lucitone 199 resin produced the highest bond strength value (14.8 +/- 1.8 MPa). For CR inlay cement, the Met-Etch and Rocatec treated groups for Lucitone denture base resin demonstrated the highest bond strength (19.3 +/- 4.8 MPa, and 19.3 +/- 1.8 MPa, respectively). For super Bond primer, the Met-Etch treated group for Trutone resin demonstrated the highest bond strength (19.8 +/- 6.2 MPa). CONCLUSIONS: Without primer, the control had the lowest bond strength (0 MPa), and the Trutone groups showed the highest bond strength (11.7 +/- 4.1 MPa). Met- Etch and Rocatec treated groups produced higher bond strengths than the sandblasted groups. The primed specimens demonstrated significantly higher bond strengths than nonprimed specimens, except for Trutone resin, for which primed specimens produced lower bond strengths than the nonprimed specimens.   Yu, W., G. Yue, et al. (1998). “Comparison of bond strengths of three denture base resins to treated nickel-chromium-beryllium alloy.” J Prosthet Dent 80(3): 354-61. PURPOSE: In-vitro bond strengths of 3 denture base resins (Trutone, Lucitone 199, and Triad) to a nickel-chromium- beryllium removable partial denture alloy (Ticonium) were tested with 3 surface pretreatments: sandblast, acid etch, and Rocatec (silica blasting), with or without primers (Dentsply, CR inlay cement, and Super Bond). MATERIAL AND METHODS: Lucitone 199 denture base resin bonded to the nonprimed sandblasted alloy specimen served as the control group. Alloy specimens were prepared, surface treated, and primed or not primed with primer. The treated specimens were then packed and processed with the denture base resin. Bonded specimens were stored in the distilled water at 37 degrees C for 24 hours, and then debonded in tension. The force at which the bond failed was noted, and bond strength was calculated in megapascals (MPa). Five replications for each condition (180 specimens total) were tested. RESULTS: Significant differences in bond strength were observed with primer, the most important factor, followed by pretreatment and denture base resin. Without primer for all 3 denture base resins, the Met-Etch and Rocatec treated group showed significantly higher bond strengths than the sandblasted groups. For Trutone denture base resin, nonprimed treated groups produced significantly higher bond strength than those for the other 2 denture base resin, nonprimed treated groups produced significantly higher bond strength than those for the other 2 denture base resins. The control group had zero bond strength. For Dentsply primer, the Rocatec treated group bonded to Lucitone 199 resin produced the highest bond strength value (14.8 +/- 1.8 MPa). For CR inlay cement, the Met-Etch and Rocatec treated groups for Lucitone denture base resin demonstrated the highest bond strength (19.3 +/- 4.8 MPa, and 19.3 +/- 1.8 MPa, respectively). For super Bond primer, the Met-Etch treated group for Trutone resin demonstrated the highest bond strength (19.8 +/- 6.2 MPa). CONCLUSIONS: Without primer, the control had the lowest bond strength (0 MPa), and the Trutone groups showed the highest bond strength (11.7 +/- 4.1 MPa). Met- Etch and Rocatec treated groups produced higher bond strengths than the sandblasted groups. The primed specimens demonstrated significantly higher bond strengths than nonprimed specimens, except for Trutone resin, for which primed specimens produced lower bond strengths than the nonprimed specimens. For Information, Comments, or to Contribute to this site please contact: webmaster@beryllium.org