[Evaluation of the efficacy of modified Twin-block appliance combined with micro-implant anchorage in the treatment of Angle Class Ⅱ division 1 malocclusion].

PURPOSE: To explore the effectiveness of improved Twin block appliances combined with micro-implant anchorage in correction of Class Ⅱ division 1 malocclusion.

METHODS

A retrospective analysis of medical records of 96 patients with Class Ⅱ division 1 malocclusion treated at Rugao Hospital of Traditional Chinese Medicine from January 2018 to January 2022 was conducted. The patients were divided into experimental group (n=52) and control group (n=44) based on the treatment methods. The control group was treated with modified Twin-block appliance, while the experimental group was treated with modified Twin-block appliance combined with micro-implant anchorage. Comparison was made between the two groups regarding treatment duration, time to achieve bite opening, alignment time, ANB angle, SNB angle, SNA angle, U1-NA angle, U1-NB angle, U1-SN angle, L1-MP angle, upper lip protrusion(ULP), lower lip protrusion (LLP), Z angle, plaque index (PLI), gingival index (GI) and sulcus bleeding index (SBI). Complications and patient satisfaction were recorded. SPSS 24.0 software package was used for statistical analysis of the data.

RESULTS

The treatment duration, time to achieve bite opening and alignment time in the experimental group were significantly shorter than those in the control group (P＜0.05). After treatment, ANB, U1-NA and U1-SN of the two groups were lower than before treatment, and the experimental group was significantly lower than the control group (P＜0.05). U1-NB and L1-MP were higher than those before treatment, and the experimental group was significantly higher than the control group (P＜0.05). There was no significant difference between SNB and SNA (P＞0.05). After treatment, ULP and LLP of the two groups were lower than before treatment, and the experimental group was significantly lower than the control group(P＜0.05). Z-angle of the experimental group was significantly higher than that of the control group(P＜0.05). PLI in the experimental group was significantly lower than that in the control group (P＜0.05). There was no significant difference between GI and SBI (P＞0.05), and there was no significant difference in satisfaction between the two groups(P＞0.05).

CONCLUSIONS

The modified Twin-block appliance combined with micro-implant anchorage can help to shorten the treatment time, improve the jaw and facial soft tissue contour, and promote the recovery of dental aesthetics.