[Partial recovery of thermal sensory functions in skeletal Class Ⅲ patients undergoing orthognathic surgery].

[PURPOSE] To clarify whether trigeminal somatosensory function will be changed after orthodontic treatment as well as after orthognathic surgery.

[METHODS] A series of 20 patients with a mean age of 20.9±1.74 years were recruited. Thermal quantitative sensory tests were conducted before orthodontic treatment (T0), before orthognathic surgery (T1), 2 months after orthognathic surgery (T2), and 6 months after orthognathic surgery (T3). The cold detection threshold (CDT), cold pain threshold (CPT), warm detection threshold (WDT) and heat pain threshold (HPT) were determined. SPSS 16.0 software package was used for statistical analysis.

[RESULTS] There were significant differences with lower threshold (higher sensitivity) in V2L (P=0.006) and V2R (P=0.017) for WDT at T1 compared to T0. A significantly higher threshold (lower sensitivity) was detected for CDT in V2L (P=0.028) at T1 compared to T0. A significantly higher threshold (lower sensitivity) was detected for HPT in V2R (P=0.028) and V3R (P=0.017) at T1 compared to T0. There were significant differences with higher threshold (lower sensitivity) V3L (P=0.024) for WDT at T3 compared to T0. A significantly lower threshold (higher sensitivity) was detected for CPT in V2R (P=0.036), V3L (P=0.012) and V3R (P=0.044) at T3 compared to T0. There were significant differences with higher threshold (lower sensitivity) in V2L (P=0.009), V2R (P=0.034), V3L (P=0.032) and V3R (P=0.001) for HPT at T3 compared to T0.Numbness was reported most frequently at T2 (93.33%), but this symptom tended to decrease with time (T3-20%).Fisher's exact test showed that there was no significant difference at T2(P=0.303) and T3(P=0.530) between participates who underwent genioplasty or not.

[CONCLUSIONS] The results indicated that thermal somatosensory function was altered after initial orthodontic treatment and orthognathic surgery. However, partial recovery of thermal sensory function can be expected in the majority of patients.