Maxillary Sinus Floor and Posterior Root Apices in CBCT Images

Objectives: Molars root apices are usually in contact with or projected into the maxillary sinus floor (MSF) and may facilitate to spread a periodontal or pulpal infection within the maxillary sinus, leading to a sinusitis condition. Thus the purpose of this work was to verify the relationship between the MSF and posterior root apices in CBCT images. Methods: 30 CBCT exams obtained with a 0.3mm voxel size were randomly selected and visualized using the i-CAT Vision software. A standard sequence for evaluation of the MSF and posterior maxillary teeth was established, starting with the parassagital reconstructions from the posterior area toward the anterior one, right and left side respectively. Then it was used the axial, coronal and sagittal reconstructions, sequentially. The posterior root apices were divided in close contact with the MSF (group 1) and root apices projected into the MSF (group 2). Each first and second molar root were analyzed individually, while no root differentiation to third molars and premolars were made, due to the fact that these roots were fused in most of the cases. Results: In a total of 30 CBCT exams, 21 were women and 9 men, with a mean age of 44.5 years (range 21-76 years). A total of 341 roots were evaluated, 79 (23,1%) were classified as group 1 with a higher incidence for the second molars, where 33 roots were found, followed by the first molars with 28 roots. The group 2 presented 51 (14.9%) roots with a higher incidence for the second molars, 33 roots, followed by the first molars with 14 roots. Conclusion: There was a high prevalence of posterior tooth roots in close contact with MSF. Therefore, dentists must be aware about this relationship during an endodontic or surgical treatment planning in order to avoid penetrating the sinus cavity.