Association of Upper Lip Length With Craniofacial Structures in Adults: A Cross-Sectional Study.

BACKGROUND

Although studies have investigated the aesthetic standard of the lower third of the face and lips, few have examined the association between the upper lip and craniofacial structures. This study aims to evaluate the association between upper lip length (defined as the distance between the base of the nose and the upper lip) and craniofacial structures in adults.

MATERIALS AND

METHODS

Two hundred twenty-five radiologic data were obtained by x-ray examination and cone beam computed tomography (CBCT). Three different methods used to measure upper lip length (ULL) for subsequent experiments are as follows: the cutaneous upper lip length (CULL), the total upper lip length (TULL), and the length ratio of the total upper lip length relative to the total anterior facial height (TULL/N-Me). Statistical analysis was performed using SPSS 26.0 software (significance value P <0.05).

RESULTS

The study highlights significant sex and BMI differences in lip length and craniofacial structures, with normal-weight males showing longer lips and larger maxillary bone dimensions (length, width, vertical height) than females ( P <0.001). Pearson correlation analysis revealed a strong association between lip length and maxillary length (sagittal direction) in males and a strong association between lip length and facial height (vertical direction) in females.

CONCLUSIONS

A longer upper lip may be associated with a correspondingly longer maxilla in the sagittal dimension in males and increased facial height in the vertical dimension in females.