Evaluating upper lip changes during smiling and at rest in Indian population.

Context: Smile aesthetics is one of the major goals to be achieved after orthodontic mechanotherapy as it visibly displays the results of orthodontic treatment. Although orthodontic retainers aid in maintaining post-treatment occlusion, soft tissue function and aesthetics, appropriate knowledge of smile changes with age can help orthodontists to obtain stable and aesthetically appealing treatment results. Aim: To assess and quantify soft tissue changes in the upper lip in vertical dimension at both repose and maximum smiling and to evaluate changes occurring with the smile index and upper lip with age and sex in subjects of Indian origin. Settings: Department of Orthodontics and Dentofacial Orthopaedics, Army College of Dental Sciences, Secunderabad, Telangana, India. Design: Observational study Methods and Materials: A total of 160 volunteers (80 males and 80 females) selected and were divided into 4 groups according to age and were further divided into 2 sub-groups according to gender. Thirteen measurements of relaxed and smiling upper lip were taken with a calibrated metal ruler and divider directly on the subjects. Statistical Analysis Used: Analysis of variance (ANOVA) was done followed by post hoc test to determine which groups were significant from others. Levene's test was done to assess equality of variance and t-test for equality of means was done. Results: Statistically significant results were obtained in between groups and sub-groups for parameters like smile index, upper lip elevation while smiling and smile pattern in males and females changing with increase in age. Conclusions: High smile patterns with more vertical smile are more common among females and low smile patterns are more common among males. With age, the smile tends to be more horizontal in both genders.