Abstract:

Objective To explore the effect of using invisible appliances to correct Class Ⅱ malocclusion on the temporomandibular joint. Methods Seventy patients with Class II malocclusion were selected and divided into an observation group （n = 35） and a control group （n = 35） using the envelope method. The observation group received invisible orthodontic treatment， while the control group received self-locking bracket orthodontic treatment. The changes in temporomandibular joint angles and gaps and so on between the two groups were observed. Results The changes before and after correction of the lower internal angle at the intersection of the long axis of the upper central incisor and the anterior skull base plane （U1-SN）， angle between the long axis of the upper central incisor and the line connecting the nasal root point and the upper alveolar seating point （U1-NA） in the observation group were （11.05 ± 1.01） ° and （4.75 ± 0.76） °， respectively， which were significantly higher than those in the control group （P < 0.05）. The changes in maxillary central incisors， maxillary lateral incisors， mandibular central incisors， and mandibular lateral incisors before and after treatment in the observation group were （0.51 ± 0.21） mm， （0.40 ± 0.15） mm， （0.40 ± 0.13） mm， and （0.20 ± 0.05） mm， respectively， which were significantly lower than those in the control group （P < 0.05）. The changes in Plaque Index （PLI）， Gingival Index （GI）， and Exploration Depth （PD） before and after correction in the observation group were （0.44 ± 0.19） points， （0.41 ± 0.13） points， and （0.38 ± 0.10） mm， respectively， which were significantly lower than those in the control group （P < 0.05）. Conclusion Invisible appliances have good application value in correcting Class Ⅱ malocclusion， which is beneficial for improving the temporomandibular joint of patients.

Key words: invisible appliance correction, class Ⅱ malocclusion, temporomandibular joint