To investigate the esthetic perceptions of female maxillary central incisor and lateral incisor gingival margin asymmetries for orthodontic patients.

Female maxillary central incisor and lateral incisor gingival margin asymmetries models were set up. The distance from the gingival margin of the center incisor and lateral incisor to the incisor edge was set as 0.5 mm, 1.0 mm, 1.5 mm and 2.0 mm. A questionnaire was designed to investigate the esthetic perceptions of gingival margin asymmetries.

In general, the most attractive smiles for the orthodontic patients were the ones without asymmetries or with a 0.5-1.0 mm asymmetry (P＜0.05). The patients could be initiated the difference by an asymmetry of 1.0 mm, and the asymmetries with 1.5-2.0 mm were not acceptable for anesthetics (P＜0.05).

The perceptions of anesthetic asymmetries in the gingival margin levels of the female maxillary central incisor and lateral incisor gingival margin were 1.0-1.5 mm, and this statics is somewhat clinically instructive.

Lip soft tissue were measured and assessed before and after orthodontic treatment of Class Ⅱ division 1 adults in order to instruct the clinical work.

A total of 30 post-treatment adult patients of Class Ⅱ division 1 were selected, whose post-treatment model and cephalometric data were within the normal range. The pre- and post-treatment front image and lateral cephalograms lip sagittal thickness and vertical thickness measurement.

Post-treatment upper lip vertical become thinner and lower lip vertical thickness is bigger which has a statistically significant gap. Upper lip vermilion of the initial tissue thickness after treatment increased, lower lip vermilion of initial tissue thickness had a tendency to decrease after treatment, and there was statistical significance. The retraction of upper incisor cervical point (U1C) was positively correlated with upper lip retraction (TUL). The retraction of lower incisor cervical point (L1C) was positively correlated with lower lip retraction (TLL). And the retraction of upper incisor most anterior point was positively correlated with lower lip retraction.

Upper and lower lip retraction in Class Ⅱ division 1 Chinese adults could be effectively predicted by the retraction of incisors after extraction orthodontic treatment.