Relationship of maxillary third molar root to the maxillary sinus wall: A cone-beam computed tomography (CBCT) based study

Background. The relationship of the root of the maxillary third molars and the maxillary sinus (MS) is an important predictor of the anticipated difficulty in extraction. The aim of this study was to assess the location of maxillary third molars to the inferior wall of the MS in a sample of Pakistani population evaluated using cone-beam computed tomography (CBCT) imaging and to assess if age or gender has any influence on third molar to MS distance.

Methods. The CBCT scans of adult patients, carried out keeping image volume at 8 cm×8 cm, and the voxel size 0.2 and 0.1 mm. Images retrieved from the hospital database were included in the study. The relationship of root apices of maxillary third molar with the MS was assessed according to the vertical, horizontal and Winter’s classification. Descriptive statistics, t test and chi-square test of association were applied.

Results. CBCT scans of 93 patients, 56 males and 37 females were evaluated. The mean age was 41.12±17.13 years. The mean distance of third molar roots to the MS wall was 2.38±1.54 mm for males and 1.86±1.04 mm for females, on the left and 2.67±1.81 mm for males and 2.58±1.54 mm in females, on the right side. Independent sample t test showed that there was no significant difference for third molar to sinus wall distance in the two genders. No significant difference was found between the two sides.

Conclusion. In a sub-population of Pakistani adults, the mean distance between the roots of the upper third molar and MS wall is around 2 mm. Only 5% males and 8% females had their upper third molars roots protruding into the MS.