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Title Zirconia Abutments Cause More Wear to Titanium Implants than Titanium Abutments
Clinical Question In patients with implants, what is the effect of zirconia abutments on wear of titanium implants compared with titanium abutments?
Clinical Bottom Line Zirconia abutments will cause more wear to a titanium implant than a titanium abutment will. No evidence was found as to whether this increase in wear is clinically significant.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 23021964Stimmelmayr/20122 Implant/abutment groups evaluated. 3 zirconia abutments and 3 titanium abutments for 6 total abutments evaluated.Laboratory study
Key resultsThis article found that there is more wear to a titanium implant by a zirconia abutment compared to a titanium abutment (a mean of 10.2 µm with a standard deviation of 1.5 µm for zirconia abutments, and 0.7 µm with a standard deviation of 0.3 µm for titanium abutments). The difference between the amount of wear was found to be statistically significant (p < 0.001, Levene-test). No confidence interval was reported.
#2) 22010078Klotz/20112 implant/abutment groups were evaluated. 2 zirconia abutments and 2 titanium abutments for 4 total abutments evaluated.Laboratory study
Key resultsThis article found that there is greater wear to a titanium implant by a zirconia abutment when comparing it to the wear of a titanium implant by a titanium abutment. This was determined by looking at the area of titanium transfer (wear) from the implant to the abutment. The area of titanium transfer after 1,000,000 cycles of being loaded was 15.8 +/- 3.3 x 103 µm2 for titanium abutments and 131.8 +/- 14.5x 103 µm2. This is about six times more wear than the titanium abutment. This difference is statistically significant with p=0.0081. The article also looked at the rate of wear and found that initially the rate of wear was faster for the zirconia abutment. After about 250,000 cycles, the rate of wear slowed down for the zirconia abutment. No confidence interval was reported.
Evidence Search (((zirconia abutments) AND material)) AND wear
Comments on
The Evidence
Validity: The main aspect lacking from Stimmelmayr/2012 was a substantial sample size. Only three samples for the two materials were evaluated, so a larger sample size would be beneficial to further substantiate their findings. Additionally, the clinical significance of the difference of wear is unknown so further studies are needed. A strength of the article is the standardized way they were able to apply/test forces. A study involving actual patients would yield helpful information/data. They physically measured the wear that occurred, so one can’t refute that zirconia causes more wear. These findings are consistent with other published research, though there is little information available in the dental literature. Overall the validity of the findings is good. The greatest weakness of Klotz/2011 is the very small sample size; a larger sample size would provide better data. Also, the actual wear to the implant wasn’t measured; instead the investigators looked at the area of titanium transfer to determine wear. It seems possible that there could be the same area of titanium transfer for varying extents of actual wear. A strength of the article is the standardization achieved in the forces applied to the abutment/implant combinations. These findings are consistent with currently published literature. Perspective: Stimmelmayr/2012 demonstrates a clear difference in the amount of wear caused by zirconia and titanium abutments, which is what we are comparing. However, the article does not give us information on how this would affect care/longevity in a clinical setting, or if it is clinically significant. This study did a good job of trying to simulate the oral environment; cyclical loading, placing the implant in resin with a Young’s modulus similar to Type III cancellous bone. However, it is an in vitro, not an in vivo study. Klotz/2011 does answer the question we are addressing, but having the study designed to measure actual wear of the implant seems like it would be a more direct way to answer our question. Like the other article, we don’t know the clinical significance (if any) of more wear when using a zirconia abutment. As a result, a study evaluating the degree of clinical significance is still needed. Like the first article, this study took steps to simulate the oral environment by means of cyclic loading and using resin with a modulus of elasticity similar to that of bone. Even with these efforts, simulating the oral environment with complete accuracy is not possible, so one should keep in mind that this is an in vivo, not an in vitro, study.
Applicability Patients often present to clinic with missing teeth desiring an implant restoration to replace them. Often times these missing teeth are located in the esthetic zone, so a restorative option such as a zirconia abutment that can give an enhanced esthetic result is ideal. However, if these abutments damage the implant, particularly in a clinically significant manner, a different esthetic treatment modality is needed. This study didn’t determine if the difference in wear is clinically significant so further research is needed. Zirconia abutments are not prohibitively expensive and are readily available. As stated before, the study was an in vitro study so there will potentially be some variability in results in an actual patient.
Specialty/Discipline (General Dentistry) (Prosthodontics)
Keywords Zirconia abutment, wear, titanium implants
ID# 3354
Date of submission: 11/14/2018spacer
E-mail nelsonj1@livemail.uthscsa.edu
Author Jens D. Nelson
Co-author(s) e-mail
Faculty mentor/Co-author Michael T. Potter
Faculty mentor/Co-author e-mail potterm3@uthscsa.edu
Basic Science Rationale
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