Assessing fit at the implant-abutment junction with a radiographic device that does not require access to the implant body.
BACKGROUND
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.


OBJECTIVE
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.


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.
Private practice, San Francisco, Calif. Electronic address: kevin.kclin@gmail.com.
Kevin C
KC
Lin
Affiliate Faculty, Department of Restorative Dentistry, School of Dentistry, University of Washington; Private practice, Bellevue, Wash.
Chandur P K
CP
Wadhwani
Associate Professor, School of Dentistry, University of California, San Francisco, Calif.
Jing
J
Cheng
Health Sciences Clinical Professor, School of Dentistry, University of California, San Francisco, Calif.
Arun
A
Sharma
Health Sciences Clinical Professor and Division Chair, Prosthodontics, School of Dentistry, University of California, San Francisco, Calif.
Frederick
F
Finzen
D003442:Crowns; D059605:Dental Implant-Abutment Design; D018772:Dental Marginal Adaptation; D019094:Dental Prosthesis, Implant-Supported; D006801:Humans; D008348:Manikins; D008963:Molar; D019252:Radiography, Dental, Digital / Q000295:instrumentation*; D013499:Surface Properties