Abstract: Objective To investigate morphological characteristics of maxillary arches of unilateral complete cleft lip-and-palate (UCLP) newborns, and confirm the reliability and repeatability of a novel 3D measurement. Methods A total of 60 newborns with UCLP up to the mustard were selected. An intraoral scanner was applied to collect digital models of their initial maxillary arches and measurements were completed with Mimics software. In all, 25 items of maxillary alveolus were measured for each model twice, and then Bland-Altman analysis was done to check the consistency. All samples were divided into three groups according to morphological features, and comparative analysis was completed to study morphological differences between different groups. Results All measurements were in accordance with normal distribution and this novel 3D measurement showed clinically acceptable consistency. Length of the anterior segment of alveolus and angles of both the anterior and posterior segments of alveolus on the none-cleft side (NCS) were all greater than those on the cleft side (CS). Length of the anterior segment of alveolus on the NCS in Group 1 and 2 was significantly greater than that in Group 3. Besides, samples in Group 1 showed smaller width of the cleft and the arch in both anterior and middle parts, compared with other groups. Angular values showed that angle of the anterior segment of alveolus on the NCS in Group 1 was smaller than that of other groups. Conclusion The research summarizes average dimensions of the maxillary arches of non-syndromic UCLP newborns. Besides, it is observed that severity of cleft depends on both the insufficient length and the rotation angle of the anterior segment of alveolus on the NCS.

Key words: three-dimensional measurement, unilateral complete cleft lip and palate, newborn, maxillary alveolus