Objective:The purpose of this study was to evaluate and compare the efficacy of nasoalveolar molding (NAM) therapy in the improvement of alveolar and palatal cleft deformity on unilateral (UCLP) versus bilateral (BCLP) cleft lip and palate.Materials and Methods:A total of 19 UCLP (14 boys and 5 girls) and 8 BCLP (7 boys and 1 girl) infants completed NAM therapy were included in this study. Standardized parameters of cleft width of alveol and palate were measured on photocopies taken from the pre- and post-treatment plaster casts. To assess the intragroup differences, paired-samples test in UCLP and Wilcoxon test in BCLP groups were used. Mann-Whitney U test was used to evaluate the differences between the groups.Results:Significant decreases in alveolar and palatal cleft gaps were achieved in an average period of 3.31.9 and 3.7 +/- 1.6 months in UCLP and BCLP patients, respectively. The alveolar cleft decreased 7.85 +/- 4.59 mm in UCLP and 4.25 +/- 3.13 and 3.81 +/- 3.50 mm in right and left alveolar cleft sides in BCLP, respectively. The palatal clefts were decreased 4.63 +/- 2.44 mm in medial and 3.72 +/- 2.62 mm in posterior parts in UCLP. The decrements in BCLP were 3.00 +/- 2.75 mm in medial and 2.88 +/- 2.75 mm in posterior palatal cleft distances. No significant differences were determined in the amount of alveolar or palatal cleft closure between UCLP and BCLP groups. The only decrease in arch width was 1.39 mm in medial part of palate in UCLP.Conclusion:The NAM device provides significant decreases in both alveolar and palatal cleft deformities in UCLP and BCLP infants, as compared with their birth status.