The aim of the present study was to compare masticatory and mimetic muscle thickness and buccal fat pad (BFP) dimensions between the operated and non-operated sides using ultrasonography in individuals who had undergone unilateral BFP-based oroantral closure.

This prospective cross-sectional observational study included 30 individuals who had undergone unilateral closure of an oroantral communication using the BFP. Ultrasonographic measurements were used to assess the thickness of the masseter muscle (at rest and during contraction), anterior temporalis, buccinator, risorius, and zygomaticus major muscles, as well as BFP dimensions, on both the operated and non-operated sides. Comparisons were performed between sides according to postoperative follow-up duration and gender. Statistical analyses were conducted using appropriate parametric or nonparametric tests, with a significance level of p < 0.05.

A total of 30 individuals (mean age: 42.00 ± 13.53 years; 76.7% male) were included. The resting masseter thickness was significantly lower on the operated side compared to the non-operated side (8.35 ± 2.28 mm vs. 8.94 ± 1.94 mm; p = 0.049). Similarly, the BFP area was significantly smaller on the operated side than on the non-operated side (42.55 ± 19.16 mm² vs. 51.94 ± 23.32 mm²; p = 0.002). No significant differences were observed for contracted masseter measurements, temporalis, buccinator, risorius, or zygomaticus major (p > 0.05). Across postoperative time points, a significant difference was observed only in BFP measurements in the 12-month group (p < 0.001). A significant negative correlation was found between age and BFP measurements on the operated side (r = −0.470, p = 0.009).

In individuals who had undergone unilateral BFP-based oroantral closure, the operated side showed smaller resting masseter thickness and BFP area than the contralateral non-operated side, whereas no significant side-to-side differences were observed in the remaining evaluated muscles. Because preoperative ultrasonographic measurements were unavailable, these findings should be interpreted as postoperative side-to-side differences rather than definitive surgery-induced changes. USG may be a useful tool for postoperative assessment of regional soft-tissue morphology.