Evaluation of the association between OXIS interproximal contact morphology and plaque and gingival indicators in children

Context: Interproximal contact morphology of primary molars influences plaque retention and self-cleansing ability, which may affect plaque accumulation and gingival health in children. However, evidence linking open, point, straight/broad, or curved/broad (OXIS) contact types with plaque-related gingival indicators in the primary dentition remains limited. Aim: To evaluate the association between OXIS interproximal contact morphology and plaque and gingival indicators in children aged 3–9 years. Materials and Methods: This cross-sectional observational study included 98 systemically healthy children aged 3–9 years, with sample size determined using G*Power software. Interproximal contacts between primary molars were clinically classified as OXIS. Plaque accumulation and gingival inflammatory status were assessed using the Plaque Index, Gingival Index, and Russell’s Periodontal Index, which reflects plaque-induced gingivitis rather than true periodontal disease in children. Data were analyzed using one-way ANOVA, Tukey’s post hoc test, and multivariate regression analysis ( P < 0.05). Results: Open contacts were the most prevalent (38%). X-type contacts demonstrated significantly higher plaque and gingival scores compared with O-type contacts ( P < 0.001). I-type contacts also showed higher scores, while S-type contacts did not demonstrate significant differences. X- and I-type contact morphologies were identified as independent predictors of increased plaque accumulation and gingival inflammation. Conclusion: OXIS interproximal contact morphology is significantly associated with plaque accumulation and gingival status in the primary dentition. X-type contacts exhibit the highest plaque-retentive potential, emphasizing the relevance of OXIS assessment in identifying plaque-retentive sites that may benefit from targeted preventive care in children.