| 摘要: | Introduction: Many methods have been used to evaluate smile esthetics. Meanwhile, the clinical 3D facial assessment using optical-based imaging techniques has shifted in favor. These techniques are completely non-invasive and non-contact imaging systems that offer superior accuracy, reliability, and speed compared to 2D photography. The aims of this research are to quantify the relationship between 3D smile variables and different types of craniodentofacial morphology, to quantify the facial soft tissue displacements that occur during the transition from rest to posed smile, and to compare coordinate values between 3D smile variables and different types of craniodentofacial morphology.
Materials and Methods: The patients aged between 18-30 years old in the orthodontic department of Taipei Medical University Hospital were grouped based on four craniodentofacial variables divided into two horizontal dimensional variables; OJ and ANB, and two vertical dimension variables; OB and FMA. Each variable has three groups; group1 (variable value within norm), group 2 (variable value more than norm), and group 3 (variable value less than norm). 3D surface images were obtained during rest and smile. The images were superimposed, then the landmark position, linear, angular, proportional measurements and the landmark displacement were recorded, compared and analyzed by ANOVA method. The correlation between craniodentofacial variables and those measurements were analyzed by Pearson correlation coefficient.
Results: Almost all the landmark positions showing the significant differences (P<0.05) among three groups based on horizontal craniodentofacial variables (both OJ and ANB) limited in z-plane. The intercommissural width of ANB group 1 at smile was the largest and differed significantly (P<0.005) from group 3. FMA group 2 presented the largest interlabial gap at both rest and smile, followed by group 1 and group 3 consecutively. The Labiomental angle was the largest in ANB group 3 but smallest in ANB group 2 at rest and smile, and was the largest in OB group 3 (open bite) but smallest in OJ group 2 (deep bite) at rest. The lower lip movements in OJ and ANB group 3 were significantly less than those in group 1 and 2 (P<0.05). High negative correlations were found between ANB and soft tissue variables in z-plane.
Conclusion: The four craniodentofacial variables affect the soft tissue smile measurements in different aspects. The horizontal craniodentocafial variables (OJ and ANB) have more influence on soft tissue smile variables than vertical craniodentocafial variables (OB and FMA) |
