Prevalence of Proximal Overhangs in Class II Composite Restorations Placed by Undergraduate Students at Qassim University

Background Proximal overhangs in class II composite restorations are common technical errors that can contribute to plaque retention and localized periodontal inflammation. This study aimed to assess the prevalence of proximal overhangs in class II composite restorations placed by undergraduate dental students at Qassim University, Buraydah, Saudi Arabia, using bitewing radiographic analysis. Methods A retrospective cross-sectional study was conducted at the College of Dentistry, Qassim University. Competency sheets from fourth- and fifth-year students during the 2023-2024 academic year were reviewed. Bitewing radiographs meeting inclusion criteria (vital permanent teeth with good-quality images) were analyzed. Exclusion criteria included missing adjacent teeth and third molars. Two calibrated evaluators assessed each radiograph with high inter- and intra-examiner reliability (Cohen's kappa = 0.90). Data were analyzed using SPSS Version 23, and chi-square tests were applied (p < 0.05). Results Of the 292 restorations reviewed, 84 (28.8%) met inclusion criteria. Among these, 21 (25%) showed proximal overhangs. Fifth-year students recorded 14 (28%) overhangs versus 7 (20.5%) among fourth-year students (p = 0.793). Female students showed 7 (26%) overhangs compared to 14 (24.6%) for males (p = 0.892). Overhangs were slightly more frequent in maxillary 10 (26.3%) than mandibular 11 (24%) restorations (p = 0.800). Mesial surfaces exhibited 12 (27.9%) overhangs compared to 9 (22%) on distal surfaces (p = 0.529). No associations were statistically significant. Conclusion One in four class II composite restorations placed by undergraduate students at Qassim University showed proximal overhangs, with no significant difference by academic year, gender, arch, or surface. The findings highlight a continued need to strengthen matrix adaptation and finishing techniques in undergraduate restorative training.