การทำนายการเปลี่ยนแปลงของริมฝึปากภายหลังการถอยฟันหน้าในผู้ใหญ่ที่มีการสบฟันผิดปรกติประเภทที่ 2 ดิวิชั่น 1

Abstract

Objective: 1. To evaluate lip changes in the antero-posterior and vertical direction after incisors retraction in Thai adult patients with Class II division 1 2. To evaluate the relationship between lip and dental changes in the antero-posterior and vertical direction and make the predictions. Materials and Methods: The sample consisted of pre- and post- treatment lateral cephalograms. The samples were derived from 100 Thai adult female patients (age 21.5 ± 4.98 years) with Class II division 1 treated with four premolar extraction and subsequent retraction of anterior teeth. Cephalograms were tracing and evaluated for dental and lip changes. Paired t-test was used for testing the difference before and after orthodontic treatment and performed the ratios, Pearson's correlation analysis was used to evaluate the factors that correlated with lip changes and Stepwise multiple regression was performed to make the predictions. Results: 1. There was significant changes of lip after incisors retraction in antero-posterior and vertical direction at 0. 01 significant level. 2. There was significant correlation between lip and dental changes in antero-posterior and vertical direction at 0.01 significant level. Conclusions: The ratios of upper and lower incisors retraction to upper and lower lips retraction, the ratios of upper incisors extrusion to upper lip extrusion and lower incisors intrusion to lower lips extrusion in Thai adult female with Class II division 1 were I(cervical area): 0.88, 1(tip point): 1, 1(tip point): 1.78 and 1(tip point): 0.43, respectively. The multiple regression equations which calculated from Thai adult females with Class II division 1 were as follows. AH-Ulip -0.55(AH-CUI) - 1.2 AH-Llip-0.51(AH-LI) -0.47(pretreatment lower lip thickness) + 4.55 AV-Ulip-0.29(pretreatment interlabial gap)+0.41(AV-1UI) + 0.25 AV-Llip-0.48(pretreatment interlabial gap) +0.42(AV-CLI) -0.15 • AGAP -0.89(pretreatment interlabial gap) + 0.24(pretreatment incisal show) -0.21