Evaluation of tooth preparation for proximal cavities on molars in preclinical setup under naked eye, surgical loupes, and dental operating microscope

Objectives: The present study was conducted in February 2019 to evaluate proximal cavity preparations for molars under naked eye, magnifying loupes and surgical operating microscope by two evaluators, using modified versions of Ryge’s criteria of “Rating System for Quality Evaluation of Prepared Cavities” and the “Quality Evaluation Criteria for Prepared Amalgam Cavities.” And to assess the inter-examiner agreement. Methods: Two senior faculty evaluated the tooth preparation for Class II (MOD) cavity for amalgam restoration, on 52 no. Typodont lower molar teeth at the Pre-clinical lab, using surgical loupes, dental operating microscope and naked eye. They used the modified criteria originally suggested by Dr. Gunnar Ryge for evaluation of rating system and quality evaluation. Data were evaluated statistically using G*Power 3.1.2 software with effect size 0.5, 95% confidence interval and 80% power. Results: Inter examiner reliability for rating system for quality and quality evaluation of tooth preparation is Cronbach’s alpha 0.91 with surgical microscope. Moderate to strong agreement between examiners was found for dental loupes for rating system and quality of tooth preparation with Cronbach’s alpha values of 0.74 and 0.91. Weak agreement was present between examiners for naked eye evaluation for rating system of quality (Cronbach’s alpha-0.43). Moderate agreement for quality evaluation for tooth preparation (Cronbach’s alpha-0.76) work by the faculty is better with surgical microscope, followed by loupes and then for naked eye for both the evaluators, with moderate agreement between them. Conclusion: Quality of evaluation increases with higher magnification.