Abstract
Statement of Problem. Prosthetic gold screw fracture remains a clinical problem in implant prosthodontics.
Purpose. This study examined hexed gold prosthetic screws for internal defects and determined
the effect of these defects on tensile strength. The microstructure, microhardness,
and major constituents of the alloys also were determined. Material and Methods. Four intact hexed gold prosthetic screws, 1 from each of 2 different lots from 2
manufacturers (Implant Innovations and Nobel Biocare), were examined with standard
metallographic techniques for defects, microstructure, microhardness, and major alloy
constituents. Thirty-six screws, 9 from each of the 2 different lots of both manufacturers,
were subjected to tensile testing to determine fracture load values. Analysis of variance
and Tukey tests were used to identify differences between manufacturers and lots (P<.05). The fracture sites were examined retrospectively with a scanning electron microscope
to identify defects that could have contributed to failure. The mode of fracture was
characterized. Results. There were no significant defects in the screws tested, but differences were observed
in the microstructure, microhardness, alloy composition, and fracture load values
for both manufacturers. Screws from the 2 manufacturers demonstrated distinctly different
metallurgical characteristics, which highlighted differences in the manufacturing
processes. Fracture load values ranged from 850 ± 20 N to 1093 ± 64 N. A significant
difference was noted for mean fracture load values for the different lots of Implant
Innovations screws (P<.05). Ductile fracture was the mode of failure. Conclusion. The results of this study suggest that variability in the physical properties of
similar hexed gold prosthetic screws made by different manufacturers, as well as different
lots from the same manufacturer, may affect clinical success. (J Prosthet Dent 2002;87:30-9.)
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References
- The longitudinal clinical effectiveness of osseointegrated dental implant: the Toronto study. Part III: Problems and complications encountered.J Prosthet Dent. 1990; 64: 185-194
- A study of 589 consecutive implants supporting complete fixed prostheses. Part II: Prosthetic aspects.J Prosthet Dent. 1992; 68: 949-956
- Complications with osseointegrated implants.J Prosthet Dent. 1989; 62: 581-585
- Implant treatment in partially edentulous patients: a report on prostheses after 3 years.Int J Prosthodont. 1994; 7: 143-148
- Retrospective review of 1170 endosseous implants placed in partially edentulous jaws.J Prosthet Dent. 1998; 79: 415-421
- The role of screws in implant systems.Int J Oral Maxillofac Implants. 1994; : 48-63
- Forces and moments on Brånemark implants.Int J Oral Maxillofac Implants. 1989; 4: 241-247
- Clinical complications of osseointegrated implants.J Prosthet Dent. 1999; 81: 537-552
- Load and designs of screw joints for single crowns supported by osseointegrated implants.Int J Oral Maxillofac Implants. 1992; 7: 353-359
- Comparison of “look-alike” implant prosthetic retaining screws.J Prosthodont. 1995; 4: 23-27
- Torque required to loosen single-tooth implant abutment screws before and after simulated function.Int J Prosthodont. 1993; 6: 435-439
- Theoretical analysis of fatigue life of fixture screws in osseointegrated dental implants.Int J Oral Maxillofac Implants. 1992; 7: 26-33
- A comparison of implant/prosthesis loading with four clinical variables.Int J Prosthodont. 1995; 8: 421-433
- Effect of preload torque on the ultimate tensile strength of implant prosthetic retaining screws.Implant Dent. 1994; 3: 17-21
- Elongation and preload stress in dental implant abutment screws.Int J Oral Maxillofac Implants. 1995; 10: 529-536
- Analysis of metallurgical failures.in: 2nd ed. John Wiley and Sons, New York1987: 136
- Phillip's science of dental materials.in: 10th ed. WB Saunders Co, Philadelphia1996: 49-74
- Ultimate tensile strength of five interchangeable prosthetic retaining screws.Implant Dent. 1996; 5: 16-19
- Metals handbook. 9th ed. Metallography and microstructure. Vol. 9. American Society for Metals, Materials Park (OH)1985: 30
- Metallurgy for the non-metallurgist.in: American Society for Metals International, Materials Park (OH)1998: 254
- Structure and properties of engineering materials.in: 5th ed. McGraw Hill, Boston1977: 101-103 (44-57)
- Comparison between optical microscopy and scanning acoustic microscopy for detecting flaws in concrete.Experimental Techniques. 1994; 18: 24-28
- Scanning acoustic microscopy.Ultrasonics. 1993; 31: 361-372
- The technology of metallurgy.in: Macmillan Publishing Co, Hampshire1994: 254-272
Article info
Footnotes
☆This research was supported by a 1999 Tylman Research grant and received the second-place Tylman competition award at the American Academy of Fixed Prosthodontics 50th Annual Scientific Session in Chicago, Ill., February 2001. An abstract (#1237) of the research also was presented at the 30th Annual Meeting of the American Association for Dental Research in Chicago, Ill., March 2001.
☆☆aPrivate practice, Bombay, India.
★bAssociate Professor and Director, Graduate Prosthodontics, School of Dentistry.
★★cProfessor, Mechanical and Industrial Engineering, College of Engineering.
♢dAssociate Professor (retired), Division of Dental Biomaterials, School of Dentistry.
♢♢Reprint requests to: Dr William W. Nagy, Marquette University School of Dentistry 334, PO Box 1881, Milwaukee, WI 53201-1881, Fax: (414)288-6516, E-mail: [email protected]
Identification
Copyright
© 2002 Editorial Council of The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.
