ABSTRACT
PURPOSE: This study aims to assess the effectiveness of the 3Shape TRIOS intraoral scanner (IOS) in student crown preparation evaluation. DESIGN: Students were tasked to perform a full metal crown preparation on the upper left first molar on a patient simulator within 45 minutes. Marginal Width, Occlusal Reduction, Presence of Undercuts, Taper, Planes of Reduction, Line Angles, Conformity to Gingival Contour, and Smoothness were evaluated via 3 assessment modes: (a) Conventional assessment by 2 supervisors; (b) Conventional assessment by students; (c) Digital assessment by students. Agreement between assessment modes was investigated using Kappa (κ), with a threshold set at κ > 0.4. Effectiveness of IOS for objective parameters was determined via physical verification, while that for subjective parameters was defined by agreement with the stricter supervisor grade. RESULTS: Substantial agreement (κ = 0.631) was found between IOS measurement of Marginal Width and physical verification. Two of 5 subjective parameters met κ > 0.4 for agreement between IOS and the stricter supervisor grade. Agreement between supervisors ranged from slight (κ = 0.103) for Occlusal Reduction to Fair (κ = 0.399) for Marginal Width. Agreement between conventional assessments of supervisors and students ranged from less than chance (κ = -0.142) for Occlusal Reduction to moderate (κ = 0.577) for Line Angles. Agreement between conventional assessments of supervisors and digital assessments of students ranged from slight (κ = 0.130) for Planes of Reduction to moderate (κ = 0.538) for Line Angles. CONCLUSIONS: IOS may be used to overcome limitations in conventional assessment of objective parameters and some subjective parameters. Digital assessment of crown preparations cannot completely replace conventional assessment.
