Aesthetic evaluation of gingival line and crown shape of first premolar instead of canine in unilateral maxilla
ZHANG Yan, DUAN Yin-Zhong, YUAN Feng, ZENG Guang Department of Orthodontics, Stomatological College, Fourth Military Medical University, Xi'an 710033, China
AIM: To assess the change of gingival line and the shape of the first premolar instead of canine in unilateral maxilla,as so to provide some theoretical reference for clinical treatment. METHODS: Twenty-two patients (male 9, female 13) with the upper first premolars instead of canines were selected.Their teeth were divided into 2 groups: experiment group (the first premolars instead of canines), control group (contralateral canines). The length, width, axial gradient for the crowns,the heigh of gingival line,the width of anterior dentition and the ratio of crista marginalis of their teeth were measured and analysed in their photographs and dental casts after orthodontic treatment. Differences between the 2 groups were evaluated in a paired t-test. RESULTS: Compared with the control group, significant differences were found in the 5 linear and proportional,angulars measurements in the 2 groups (P0.01),except the ratio of crista marginalis.In comparison with 5 parameters of control group,the length of clinic crown of the first premolars decreased by 2.28 mm in average;the width of clinic crown decreased by 1.00 mm in average;the height of gingival line decreased by 1.88 mm in average; the width of anterior dentition decreased by 0.95 mm in average; the axial gradient of the first premolars decreased by 4.07°in average. CONCLUSION: The first premolars can replace the canines but affect the aesthetics. So crown restoration is needed.
【CateGory Index】： R783.5