Association between Lip Prints and Skeletal Malocclusion using Digital Photography: A Cross-sectional Study

Abstract

Introduction: Lip prints are the lines and furrows observed on the vermilion border of human lips. Several studies have found a connection between lip prints, skeletal malocclusion and gender. Establishing a direct relationship between lip prints and sagittal jaw relationships in different genders can aid clinicians in early prediction of malocclusion types. Aim: To identify the association between lip prints, skeletal class I and class II malocclusions in different genders using digital photographs. Materials and Methods: An analytical cross-sectional study was conducted in the Department of Orthodontics and Dentofacial Orthopaedics at Anil Neerukonda Institute of Dental Sciences, Vishakhapatnam, Andhra Pradesh, India. The duration of the study was two months, from June 2022 to July 2022. A total of 120, out of which 60 (30 males and 30 females) participants with Angles's class I malocclusion and 60 (30 males and 30 females) with Angle's class II malocclusion were included, based on angle formed by point A, nasion (N) and point B (ANB angle) aged between 18 to 30 years. Digital photographs were captured using an SLR digital camera. The lip print pattern in a 10 mm wide area in the middle of the lower lip was determined using Suzuki and Tsuchihashi’s method. Statistical analysis was performed using the Chi-square test. Results: The most prevalent lip pattern in skeletal class I malocclusion was the branched lip pattern (type-II) in 43.33% of 60 participants, while the intersected pattern (type-III) was most prevalent in skeletal class II malocclusion with 38.33% of 60 participants. Among males, the most prevalent lip pattern was the branched lip pattern (type-II) in 46.67% of 60 participants, while in females, the vertical groove across the lip pattern (type-I) was most prevalent in 46.67% of 60 participants. Statistical significance was observed between lip pattern, skeletal malocclusion and gender (p=0.0416 in males and p=0.01397 in females). When gender is not considered, statistically significant differences were observed between the two malocclusions in (type-II) branched lip pattern (typeII) (p=0.023) and the intersected lip pattern (type-III) (p=0.001). When skeletal malocclusion is not considered, statistically significant differences were observed between the two genders in the vertical lip pattern (type-I) (p=0.001) and the branched pattern (type-II) (p=0.04). When comparing the association of lip print pattern between skeletal class I and class II malocclusions in males and females significant differences were found between skeletal malocclusion and gender (males: p=0.008, females: p=0.004) only in (Type III) intersected lip pattern. Conclusion: In conclusion, lip prints can serve as a useful tool in identifying skeletal malocclusion. The (type-III) intersected lip pattern shows a higher likelihood of predicting class II malocclusion compared to the type-II branched lip pattern, which is more indicative of class I malocclusion.