Abstract: Objective　 To investigate the subjective esthetic evaluation of lip positions by Orthodontic patients, and determine whether the patient’ s age and sex were influential factors in the esthetic assessment for providing reference for clinical orthodontic practice. Methods　 Both two frontally posed smile photographs of a man and a woman were changed by adjusting the position of upper lip with Photoshop 7.0.. A series of 11 pictures was developed for males and females, respectively. And an electronic questionnaire was designed and administered to investigation. 300 subjects included in the study were all orthodontic patients from Shandong University Stomatology Hospital. All the subjects were asked to evaluate each image according to their own aesthetic standards and choose the top 3 most-favored pictures for each sex. Results were statistically analyzed. Results　 In the comparison of age groups, there was statistically significant difference (P＜0.05). The young and middle-aged group (31- to 40-year old) and the middle-aged group (41- to 59-year old)preferred lower upper lip position than young-aged group (18- to 30-year old). There was no significant difference between male and female patients in selecting the top 3 most-favored frontally posed smile (P＞0.05). Conclusions　The esthetic evaluation of lip positions of orthodontic patients are influenced by age. Orthodontists should pay attention to patient's aesthetic expectations during orthodontic treatment.

Key words: orthodontic patients, smile, lip position, aesthetic evaluation