Quantitative sensory testing of mandibular somatosensory function following orthognathic surgery - A pilot study in Chinese with Class III malocclusion

BACKGROUND: Somatosensory changes after sagittal split ramus osteotomy (SSRO) have not been fully studied in Chinese patients by the latest technologies.

OBJECTIVE: To provide a comprehensive analysis of somatosensory function at the lower lip and chin at different time points following SSRO in a Chinese population.

METHODS: A total of 22 patients (18-27 years; nine men) with skeletal III malocclusion and scheduled for SSRO were recruited. Quantitative sensory testing (QST) was performed at pre-operation (baseline), 1 week (1W), 1, 3 and 6 months (1M, 3M, 6M) post-operatively. Cold detection threshold (CDT), warm detection threshold (WDT), cold pain threshold (CPT), heat pain threshold (HPT), mechanical detection threshold (MDT), mechanical pain threshold (MPT), pressure pain threshold (PPT) and two-point discrimination threshold (2PD) were tested at the lower lip and chin.

RESULTS: Except for PPT at both test sides at 1W and 1M, all QST values indicated a significantly reduced sensitivity (p < .05). All values had returned to baseline values at 3M with exception of HPT at the right chin which, however, had recovered at 6M (p > .05).

CONCLUSIONS: Somatosensory function at the lower lip and chin appears to be fully recovered in the majority of young Chinese adults 6 months after SSRO for skeletal class III malocclusion.