The relationship between interproximal width and intrabony periodontal defects

Objectives: Evaluate the relationship between interproximal distance and intrabony periodontal defects. Several previous studies have evaluated the role of interproximal distance on the periodontal bone defects, however, the influence on intraosseous defects has not yet been fully clarified. Materials and Methods: This study included 201 periodontitis patients. Baseline radiographs were analysed in a dedicated software management system. Interproximal width was categorised into 4 groups according to thresholds in existing literature describing the pathogenic process of bone resorption. As some of the categories contained sparse data, a second sub-categorisation based on 0.5 mm increments was added. Statistical tests were performed using IBM SPSS Statistics (Version 29) and included a Chi-Squared correction, logistic regression and Spearman correlation. Multilevel analyses were conducted to account for clustering, these tests included site and patient factors. Results: Chi-squared tests on categorised interproximal width data demonstrated that the narrower the width category, the lower the prevalence of intrabony defects. When accounting for clustering in a multilevel analysis, interproximal width category explained a significant proportion of variance. Smoking and age were also found to be statistically significant predictors. Likewise, a positive correlation was identified between the continuous measure of interproximal width and intrabony defect presence. A Spearman's correlation between interproximal width and extent of intrabony defects present showed a weak positive correlation. Conclusion: All statistical tests performed identified a statistically significant positive correlation between larger interproximal widths and the presence of intrabony defects, adding evidence to the importance of anatomical factors in the pathogenic process of periodontitis. Clinical Significance Statement: The process of bone destruction leading to intrabony defects is thought to be correlated to the aggressiveness of bone resorption, morphology of the alveolar bone, the position and anatomy of the affected teeth. This makes a compelling case to understand the morphology of intraosseous defects.