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An Improved Mechanical Testing Method to Assess Bone-implant Anchorage
Published on: February 10, 2014
Assessing fit at the implant-abutment junction with a radiographic device that does not require access to the implant
Kevin C Lin1, Chandur P K Wadhwani2, Jing Cheng3
1Private practice, San Francisco, Calif.
Statement Of Problem:
Radiograph paralleling devices provide an excellent means of obtaining orthogonal radiographs for the evaluation of the fit of implant restorations. Unfortunately, the clinical applicability of such devices is a significant issue because access to the implant body must be obtained at each radiographic appointment.
Purpose:
The purpose of the study was to investigate whether the fit or microgap at the implant-abutment junction could be more accurately and confidently assessed with a novel radiograph paralleling device that did not require access to the implant body once a proper registration index was made.
Material And Methods:
Microgaps of 0, 50, and 100 μm were introduced at the implant-abutment junction of a provisional implant crown in a manikin-typodont assembly. Dental assistants made 54 radiographs (18 per microgap) of the crown with and without a radiograph paralleling device; 9 clinicians then evaluated the standardized radiographs for the presence of misfit. The Cochran-Mantel-Haenszel test and the corresponding odds ratios were used to evaluate the effectiveness of the paralleling device in helping clinicians better assess misfit from the radiographs made.
Results:
The use of the device led to a higher percentage of accuracy under all conditions (79.0% vs 70.4% at the 0-μm gap, 77.8% vs 16.1% at the 50-μm gap, and 100% vs 92.6% at the 100-μm gap); the improvement was statistically significant at the 50-μm gap (P<.001) and 100-μm gap (P=.049) but not at the 0-μm gap (P=.364). The odds ratio (95% confidence interval) of obtaining correct versus wrong answers with the device compared with without the device was 18.64 (7.94-43.77) at the 50-μm gap and 5.40 (0.25-114.25) at the 100-μm gap.
Conclusions:
The study indicated that the paralleling device helped the clinician more accurately assess the implant-abutment junction with the 50- and 100-μm gaps.
