Assessment of conventional and digital radiographic methods in the diagnosis of marginal fit of the implant-abutment interface

Abstract

Purpose: To evaluate digital and conventional radiographs in the assessment of the implant/abutment interface with different marginal openings. Material and methods: Custom-made abutments were manufactured. Polyester matrix strips with 50 µm thickness were used as spacers to simulate different marginal openings. Abutments were evaluated radiographically in 3 different positions, with 5 different marginal opening situations: marginal fit (0µm- without spacers), 50 µm (1 spacer), 100 µm (2 spacers), 150 µm (3 spacers), and 200µm (4 spacers). A total of 150 radiographic images were made: 75 with the conventional system, and 75 with the digital system. For each image, 2 sites were evaluated (mesial and distal). A decision matrix was used to calculate sensitivity, specificity, accuracy, positive and negative predictive values, with 95% confidence intervals (CI).  Results: Overall sensitivity of both conventional and digital radiographs was 95% (CI= 86.3% to 98.29%). Specificity of the conventional radiographs was 100% (CI= 79.61% to 100%). Similarly, digital images showed high specificity of 93.33% (CI= 70.18% to 98.81%). Overall diagnostic accuracy was 96% (CI=88.89% to 98.63%) for conventional, and 94.7% (CI=  87.07% to 97.91%) for digital images. Positive and negative predictive values were, respectively, 100% (CI= 93.69% to 100%) and 83.33% (CI = 60.78% to 94.16%) for conventional images; and 98.28% (CI=  90.86% to 99.7%) and 82.35% (CI= 58.97% to 93.81%) for digital systems, respectively. Marginal openings without spacers determined microscopically ranged from 0 μm to 1.06 μm (average 0.39 μm). Conclusions: Marginal openings of 50 μm could be detected radiographically on both digital images and films. Conventional and digital radiographs are efficient diagnostic tools in the assessment of marginal fit, even with marginal openings as small as 50 μm.