The effects of interproximal distance between roots on the existence of interdental papillae according to the distance from the contact point to the alveolar crest

Background: This study investigated the existence of interdental papillae at certain distances from the contact point to the alveolar crest, depending on the interproximal distance between roots. Methods: A total of 206 papillae from 80 patients were examined after the inflammation of the papillae had been minimized using non-surgical periodontal therapy. The existence of the interdental papillae was determined using the following categorization: 1) papillae were deemed to be absent if they did not extend all the way up to the contact point between the teeth; and 2) papillae were determined to be present if they filled up to the entire proximal space. The interproximal distance between roots and the distance from the contact point to the alveolar crest were measured when a full-thickness flap was used. The number of papillae present interproximally between roots, according to the distance from the contact point to the alveolar crest, was analyzed using the ×2 analysis method, and the linear-by-linear association analysis method was used for trend analysis. Results: The number of papillae that filled the interproximal space decreased with increasing distance from the contact point to the alveolar crest (P<0.05). In addition, the number of papillae that filled the interproximal space decreased with increasing interproximal distance between roots (P <0.05) and became more prominently decreasing with the increasing distance from the contact point to the alveolar crest (especially 4, 5, and 6 mm) (P<0.05). Conclusion: The results suggest that the interproximal distance between roots and the distance between the contact point and the alveolar crest have an independent and combined effect on the existence of interproximal papillae.