A comparative evaluation of effect of upper lip length, age and sex on amount of exposure of maxillary anterior teeth

Abstract

Aim: The aim was to evaluate the relationship of age, sex and lip length to the amount of exposure of maxillary incisors and canine teeth. Materials and methods: Two-hundred subjects were enrolled in the study. All subjects were grouped according to the lip length and age. The exposure of maxillary central incisor and canines was measured with flexible millimeter ruler. Teeth exposure beyond the lower border of the upper lip was considered as positive exposure and the unexposed teeth were considered as negative exposure. Result: In females of age group 20 to 29, 30 to 39, 40 to 49 and 50 to 59 years, the mean exposure of central incisor was 2.16, 2.1, 2.18 mm and that of canine was 0.04, -0.36, -0.44 mm. For male of age group 20 to 29, 30 to 39, 40 to 49 and 50 to 59 years exposed 2.04, 2.04, 1.84, 1.76 mm of central incisor respectively and 0.08, -0.52, -0.4 and -0.4 mm exposure of canine. Female subjects with lip length 10 to 15, 15 to 20, 21 to 25, 25 to 30 and 31 to 35 mm showed 3.7, 3.4, 2.3, 0.9, 0.25 mm exposure of central incisor and 0.35, -0.15, -0.7, -0.8, -0.6 mm exposure of canine, respectively. Male subjects exposed 3.4, 3.3, 2.05, 0.7, 0.15 mm of central incisor and 0.4, 0.3, -0.6, -0.95, -0.7 mm of canine respective to lip length. Conclusion: The range of exposure of maxillary central incisors was wider than that of canine. The average dimensions for maxillary canines relating to age and sex were closer to the extremes of the range. The canine position relative to the maxillary lip appeared to be a more predictable determinant. Clinical significance: The result of the study can be used as a reference according to the age, sex and the lip length of the patient to correctly place maxillary anterior teeth in prosthesis.