['Evaluation of the effect of presurgical orthopedics on maxillary archform up to 6 months of age. DeSIGN: Retrospective, single-blinded, case-control study.', 'Study model sets of 75 infants with consecutive, nonsyndromic, complete unilateral cleft lip and palate (excluding Simonart bands) from 1995 to 2005.', 'All patients (PSO group, n \u200a=\u200a 14; non-PSO group, n \u200a=\u200a 61) received lip repair/vomer flap at 3 months and soft palate repair at 6 months by the same consultant surgeon. The two groups were comparable at birth (p > .01) in all archform variables.', 'Sixteen variables were computed, following single-blinded analysis using the Reflex Microscope to describe the archform in the transverse, anteroposterior, and vertical dimensions and the arch circumference. Data were analyzed using a repeated-measures hierarchical analysis of variance with a significance level of 1%.', 'Repeatability studies showed good measurement precision. Presurgical orthopedics produced no statistically significant mean change in any archform variable when compared with the non-PSO group. The difference in the mean reduction in the alveolar cleft width between the groups was 0.69 mm (95% confidence interval, -0.89 to 2.28 mm, p \u200a=\u200a .52). Lip repair produced greater change in archform than did presurgical orthopedics, reducing the mean alveolar cleft width by 4.45 mm (95% confidence interval, 3.53 to 5.37 mm; p < .001).'] Does presurgical orthopedics have no effect on archform in unilateral cleft lip and palate?