Novel Three-Dimensional Coordinate System to Analyze Alveolar Molding Effects of Pre-Surgical Nasoalveolar Molding on Infants With Non-Syndromic Unilateral Cleft Lip and Palate

Abstract The aim of this study is to establish a stable 3-dimensional (3D) coordinate system for investigating the alveolar molding effects of pre-surgical nasoalveolar molding (PNAM) on non-syndromic unilateral cleft lip and palate (UCLP) patients, basing on the Frankfort Horizontal (FH) plane. Twenty-one non-syndromic UCLP neonates who sought medical advice in the department of Orthodontics, from 2016.5 to 2017.10 were enrolled in the present study. All neonates were subjected to PNAM before the cleft lip repair. The treatment duration was 75.76 days. Silicone rubber models were obtained and scanned using a 3D laser scanner pre- and post-PNAM treatment. A 3D coordinate system based on the FH reference plane was built utilizing Rhino3D software to record the landmark 3D coordinates, to measure the distance, angle, and length variables. The Paired Student's t test and the Pearson correlation coefficient were used to calculate reproducibility and reliability of the landmark localization for repeated measurements. Changes of the measurement variables were analyzed by the Paired Student's t test. This study revealed a high reproducibility and reliability for most of the landmarks. By the end of PNAM treatment, the cleft gap was reduced with the malformation of alveolar segments aligned normally and the anterior points of both alveolar segments were rotated to the cleft side. Utilizing the FH plane to set up a rigorous and stable 3D system is meaningful. PNAM therapy is effective in reducing the severity of the maxillary deformity not only on the non-cleft side, but also on the cleft side.