The Orofacial Somatosensory Changes of Edentulous Mandible After Full Arch Implant Surgery-A Six-Month Follow Up.

Aims: To evaluate somatosensory function changes and recovery time in patients with mandibular edentulous jaw after full arch flap implant surgery using a standardized quantitative sensory testing (QST) protocol.

Materials and methods: Fourteen patients with edentulous mandibles underwent full-arch alveolar flap implant surgery, with three to four implants placed in each case. A QST battery including cold detection threshold (CDT), warmth detection threshold (WDT), thermal sensory limen (TSL), paradoxical heat sensation (PHS), cold pain threshold (CPT), heat pain threshold (HPT), mechanical detection threshold (MDT), mechanical pain threshold (MPT), wind-up ratio (WUR), vibration detection threshold (VDT), and pressure pain threshold (PPT) was performed at skin of mental region and keratinized gingiva of right canine. The QST was performed before surgery and one, three, six months after surgery. The QST data was calculated following the lasted guideline.

Results: The WUR of 3 months after surgery was higher than that before surgery and one month after surgery (WUR 3 mon = 3.81 ± 2.54, WUR before surgery = 2.19 ± 1.34, WUR 1 mon = 1.85 ± 1.27, P ≤ 0.032). The CDT of one month after surgery was lower than that before surgery and three, six months after surgery (CDT 1 mon = -1.57 ± 0.70 ℃, CDT before surgery = -1.01 ± 0.45 ℃, CDT 3 mon = -1.12 ± 0.50 ℃, CDT 6 mon = -1.04 ± 0.42 ℃, P ≤ 0.029). Z-score transformation was performed for each QST variable with the data before surgery as baseline mean and SD. In both mucosal and mental regions, the percentage of Z-scores below -1.96 and Z-scores above 1.96 before surgery and 6 months after surgery, was lower than 5%, while the Z-scores below -1.96 in 1 month after surgery was 6.36% and 7.79% respectively in mucosal and mental region, the Z-scores below -1.96 in 3 months after surgery was 6.36% and 7.14% respectively in mucosal and mental region.

Conclusion: Somatosensory abnormalities were detected in edentulous mandible patients after full arch flap implant surgery evaluated by a comprehensive QST battery even with no subjective symptom, and somatosensory function recovered after 6 months.