Changes of the upper lip in orthodontic and orthopedic treatment of angle's class II malocclusion

摘要

Aims: This study aimed to evaluate the changes in upper lips due to incisors retraction in Class II Division 1 patients treated with mandibular protraction, fixed appliances, and without extraction. Materials and Methods: The sample consisted of 64 pre- and post-treatment lateral cephalometric X-rays of 32 patients with 9-12 years old (16 men and 16 women), who presented ANB 4 o , overjet ≥ 4 mm, treated with Balter's Bionator and fixed appliances. The average period between initial and final radiographies was 5 years (maximum of 5.5 years and minimum of 4.5 years). Statistical Analysis Used: A Student's t-test (P 0.01) evaluated the statistical significance of differences between the mean values obtained for pre- and post-treatment in each variable, for males and females. Linear regression analysis for hard-tissue variables in relation to soft-tissue variables were also made for correlation. Results: The male group presented cervical point with r = 0.40 and incisal point with r = 0.42. Female subjects showed incisor cervical point with r = 0.86 and incisal point r = 0.74. The average Ls retraction was 0.55 mm in 2.43 mm of incisal point movement and 0.34 mm of cervical point. The nasolabial angle showed increase average of 2° for men and 3.9° for women. Conclusion: There is a difference between genders regarding the lip-incisor relation at this age. Males presented thickening of soft tissue and week correlation between the movement of the incisor and soft tissue both cervical and incisal point. In females' subjects, a strong correlation between the retraction movement and soft tissue, both cervical and incisal point.