Background: Cleft lip and palate is one of the most frequent congenital craniofacial anomalies. This defect affects aesthetic, speech, occlusion, and also psychological problems. A lot of techniques have been introduced to improve the position of the facial and oral malformations. Pre-surgical nasoalveolar molding device (PNAM) was used to decrease of the alveolar cleft width. The common method for evaluating the effects of this device is performed via palatal cast analysis with two or three dimensionally analyzed.

Objective: This study aimed to evaluate the three-dimensional changes to maxillary arches after using PNAM in unilateral complete cleft lip and palate (UCLP) patients before primary lip repair.

Materials and Methods: The samples were taken from twenty infants treated with the Khon Kaen University-PNAM (KKU-PNAM). Dental casts were obtained at two points time, i.e. pre-treatment (T1) and post-treatment (T2), they were digitized using a 3D intraoral scanner (3Shape’s R700 Scanner, Copenhagen K, Denmark). The three-dimensional models were evaluated for variations in dimension with OrthoAnalyzer™ software. For statistical analysis, paired t-test was used to compare the differences between treatment periods. Descriptive analysis and intra-class correlations were employed to characterize data.

Results: After treatment with the KKU-PNAM in UCLP patients, the results showed a significant decrease in the width between the anterior part (AG-AL; p < 0.001) and inter-canine area (CG-CL; p < 0.001). However, posterior arch width, length and height of both greater and lesser segments (PG-PL, AL/PG-PL, DG/CG plane and DL/CL plane; p < 0.001 and AG/PG-PL; p = 0.008) had significantly increased. The intra-class correlation coefficient between the reproduced landmarks, twice repeated by the same operator, were greater than 0.914. 

Conclusion: From the current study, the alveolar molding effect of the KKU-PNAM appeared to mainly decrease the anterior region of the arch, namely the area most affected by cleft lip and palate.