3D anthropometry of the nasolabial region in children aged 3 to 9 months as reference database for clinical assessment.

Treatment for a cleft lip can result in significant functional and aesthetic changes to the nasolabial region. Although three-dimensional (3D) measurements are the gold standard for evaluating cleft surgery, most short- and long-term evaluations still rely on subjective assessment or the measurement of patient photographs. To our knowledge, this work establishes the first baseline and reference group for the nasolabial region in children aged 3 to 9 months without cleft lip or palate. This group can be used for future evaluations, such as those of surgical outcomes or NAM therapy, via 3D anthropometric measurement. Data was collected cross-sectionally from 25 children aged 3 to 9 months using a validated intraoral scanner (Trios 4, 3Shape). Scans were analysed according to 3D anthropometric criteria by metrically accurate measurements of distances, surface curves and angles using 3D inspection software (GOM Inspect, Co. Zeiss, Jena, Germany). Results are presented as reference database combined with a step-by-step guide on the measurement methodology. For easy application all data are additionally presented in the form of formulae in which clinical data can be inserted. Based on the data from healthy children, we propose a new classification of alar base types ranging from 1 to 3. Unlike conventional assessment methods, surface curves and other 3D anthropometric tools provide a highly accurate and objective quantification of the anatomy of the nasolabial region and thus serve as a foundation for future clinical research on cleft lip surgery. Alar base type classification may influence future surgical approaches to cleft lip surgery.