EC Dental Science

Introduction: In dentistry, cemented fixed prosthodontics stands as a fundamental pillar, demanding absolute precision and unwavering adherence to preparation principles from practitioners to ensure proper insertion, retention, and mechanical resistance for prosthetic restorations. Retention is a key parameter for the success of a prosthesis. According to the literature, preparations require specific values, initially defined at 6°. Weed demonstrated that it is possible to reach values up to 16°, which are clinically feasible and largely acceptable. Can students replicate the recommended occlusal convergence angles for sealed unit preparations in a preclinical setting?

Objective: A digitized assessment of the total occlusal convergence (TOC) of preparations carried out by 2^nd-year students at the Faculty of Dental Medicine at Mohamed VI University of Science and Health in Casablanca during pre-clinical practical activities (APP).

Materials and Methods: A total of 357 dental preparations, performed by second-year students at Mohamed VI University of Science and Health for cast or ceramo-metallic crowns, were digitally scanned using the Smart Optique Scan box scanner. The obtained STL files were imported into the PREFORM FORMLAP software. Tangent lines were drawn at the base of the mesio-distal and buccolingual angles using a screenshot captured with the Paint tool. These tangent lines were subsequently measured using the MB Ruler software. The collected statistical data underwent analysis using SPSS software, and comparisons were conducted using the t-test.

Results: An average TOC of 13.5° +/- 4.92° was recorded for typodont preparations, with specific values of 11.02° +/- 5.31° in the mesio-distal direction and 15.99° +/- 5.81° in the buccolingual direction. No significant differences were observed in relation to students' gender. However, significant variations were noted based on the type of tooth, sector, and preparation method. 59.7% of second-year students achieved results within the 6° to 16° range.

Discussion: The results obtained in our study align with the new recommendations proposed by Weed. These findings are similar to those of studies conducted by the University of Sofia in Bulgaria and those by Yoon., et al. Most institutions worldwide have reported higher values than ours.

Conclusion: This study shows that second-year dental students at Mohamed VI University of Science and Health face challenges in achieving the recommended 6° angle for total occlusal convergence (TOC). However, the majority of those students recorded TOC values between 6° and 16°, which is consistent with findings worldwide.

 Keywords: Convergence Angle; Dental Preparation; Total Occlusal Convergence

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