Effect of body mass index on soft tissues in adolescents with skeletal class I and normal facial height

Background: The evaluation of soft tissues in patients undergoing orthodontic treatment plays a critical role in diagnosis and treatment planning. This study aims to evaluate the effect of body mass index (BMI) on facial soft tissues in skeletal Class I patients with normal vertical growth.Methods: The study included 72 patients with a normal vertical growth pattern (SNGoGn 26-38(degrees)) and skeletal Class I (ANB 2-4(degrees)) malocclusion. According to their BMI (kg/m(2)) values, the patients were divided into three groups of 24 individuals each: underweight (>5th percentile) (13 females, 11 males; mean age, 11.58 +/- 1.95 years), normal weight (5-85th percentile) (12 females, 12 males; mean age, 11.54 +/- 1.95 years), overweight (85-95th percentile) (12 females, 12 males; mean age, 11.62 +/- 2.01 years). Soft tissue thickness and height measurements were made on lateral cephalometric radiographs.Results: In all soft tissue thickness measurements, except for the nasion, the overweight weight group had higher values. In comparing the underweight and normal weight groups, statistically significant differences were found in the thickness measurements at the nasion and gnathion (p < 0.05). The differences in thickness measurements at the glabella, labiale superius, stomion, labiale inferius, pogonion, gnathion, and menton are statistically significant between the underweight and overweight groups (p < 0.005). Comparing the normal and overweight groups revealed statistically significant differences the thickness measurements at the glabella, labiale superius, stomion, pogonion and menton (p < 0.05).