Lip height estimation in a southern African sample

Abstract

INTRODUCTION: The South African Police Service frequently relies on craniofacial approximation and superimposition to assist in identifying unknown deceased individuals. Standards to estimate lip height are however limited. Findings from this study share medical applications. Aims and objectives: Establish reliable standards for estimating lip height using dentoskeletal measurements. METHODS: Cone-beam CTs comprising 124 black and 39 white southern African adults were assessed. A series of dimensions were recorded using a DICOM viewer with an inbuilt measuring tool. Relationships between hard tissue structures (maxillary, mandibular and total central incisor heights, their corresponding root lengths, face height (N-Gn), and nose height (N-Sn)) and respective overlaying soft tissues (upper, lower and total lip heights) were evaluated. RESULTS AND CONCLUSIONS: Statistically significant differences were observed between population, sex and age groups. A selection of regression equations to estimate lip height was calculated that included population, sex and approximate age (20-39 and 40+ years) for improved goodness-of-fit (r2-value). Regression models using face height produced the strongest multiple correlation (r-value) and goodness-of-fit (r2-value). Validation testing indicated that regression models often improved upon mean measurements, while offering a degree of individuality that mean values do not.