[Evaluation of the long-term effects of SGTB combined with fixed appliances in the treatment of skeletal Class Ⅱ malocclusion in adolescents].

چکیده اصلی

PURPOSE: To explore the craniofacial growth modification effect of two-stage treatment with sagittal-guidance Twin-block appliance (SGTB) combined with fixed appliances on skeletal Class Ⅱ malocclusion in adolescents, and to evaluate the long-term stability of the functional orthopedic effect of this protocol. METHODS: A total of 21 adolescent patients with Class Ⅱ division 1 malocclusion in the growth and development period were included, with an average initial age of (12.02±1.02) years. All patients received a non-extraction treatment protocol consisting of "stage 1: SGTB functional orthopedics + stage 2: fixed appliance therapy". Cephalometric analysis was performed at the initial stage of treatment (T0), after SGTB removal (T1), at the end of fixed appliance treatment (T2), and during the follow-up period after treatment (T3). Changes in craniofacial skeletal, dental and soft tissue indicators at each time point were compared to evaluate the treatment effect and stability. RESULTS: After two-stage treatment, the sagittal jaw discrepancy was significantly corrected (increased SNB angle, decreased ANB angle, reduced Wits value, and diminished overjet); the overall jaw length increased, and the mandible moved forward (Co-Gn, Co-Go, and Pog-Nperp significantly increased); maxillary growth was slightly inhibited (decreased Ptm-A, P=0.013). In addition, the upper incisors retracted, the lower dentition moved mesially, and the molar relationship was restored to Class Ⅰ. During the follow-up period (T2-T3), there was no significant recurrence of skeletal indicators (such as SNB angle, ANB angle, and Wits value) (P＞0.05); only slight physiological rebound occurred in overjet, overbite and nasolabial angle, and the overall stability was good. CONCLUSIONS: The two-stage combined treatment with SGTB appliance and fixed appliances can effectively correct skeletal Class Ⅱ malocclusion, promotes the growth of the condyle and mandible, and shows good stability in long-term follow-up.

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