It is imperative that the endodontic surgeon be knowledgeable of the anatomic dimensions of the surgical site. If cone-beam computed tomography is not available because of location/cost, it is prudent for the clinician to consult a knowledge base for the surgical site. An understanding of the root thickness of maxillary premolars and molars at the preferred level for root resection (3.0-3.6 mm), bone thickness over these roots, and the proximity of each root apex to the maxillary sinus will help the surgeon before and during the surgical procedure.
Cone-beam computed tomography scans from 155 patients were used to evaluate measurements from 505 teeth and respective areas.
(1) Buccal bone was thinnest over the buccal root of the 2-rooted first premolar (0.66 mm) and the mesiobuccal (MB) root of the first molar (0.84 mm) and thickest over the MB root of the second molar (1.91 mm). (2) The palatal bone was thinnest over the palatal root of the maxillary first molar (1.24 mm) and thickest over the single-rooted second premolar (3.26 mm). (3) The longest distances to complete resection were found for the 2-rooted first and second premolars (8.81 mm and 9.14 mm, respectively) and the MB root of the second molar (7.40 mm). (4) The MB root of the second molar had the closest proximity to the sinus floor, with an average distance of 0.66 mm.
An understanding of the maxillary posterior tooth anatomy for apical resection is beneficial to the endodontist.