Cone-beam computed tomography-based analysis of anatomical structures surrounding maxillary molars for palatal endodontic microsurgery

Abstract

This study aimed to evaluate anatomical factors influencing the palatal approach for endodontic microsurgery in maxillary molars using cone-beam computed tomography (CBCT). Understanding the spatial relationship between the palatal root apex and surrounding anatomical structures is essential for effective surgical planning. CBCT scans of 100 patients, comprising 200 maxillary first molars and 200 maxillary second molars with 3 separate roots, were retrospectively analyzed. Measurements included palatal bone thickness at the root apex and at a simulated 3-mm resection level, buccolingual root width, palatal soft-tissue thickness, the angle between the palatal root axis and the palatal soft-tissue surface, and the vertical relationship between the palatal root apex and the maxillary sinus floor. Palatal bone thickness at the apex was significantly greater in maxillary first molars than in second molars (4.01 mm vs. 3.39 mm; p<0.05). Palatal bone thickness at the 3-mm level and buccolingual root width did not differ significantly. Palatal soft tissue was significantly thicker in maxillary second molars at both measurement levels (p<0.05). The angle representing the surgical trajectory showed no significant difference between tooth types. Regarding the sinus relationship, type II (apex contacting the sinus floor) was most frequently observed in first molars, whereas type I (sinus floor above the apex) predominated in second molars. No significant difference was found in the mean apex-to-sinus distance between groups. These findings highlight the importance of CBCTbased evaluation of palatal bone, soft tissue, and sinus proximity when evaluating the feasibility and complexity of the palatal approach in endodontic microsurgery.