OBJECTIVES: Studies have shown that the mandibular permanent first molar (M1inf ) in young children with isolated cleft palate is characterized by delay in maturation and has reduced crown width. Consequently, it is of interest to investigate the early maturation and width of the follicle and crown of M1inf in children with combined cleft lip and palate.

DESIGN: Retrospective, longitudinal study. Cephalometric X-rays of 47 consecutive Danish children with UCCLP (37 males; 10 females) and 44 with unilateral incomplete cleft lip (UICL) (29 males; 15 females) examined at 2 and 22 months of age. UICL served as control group. Maturation (according to Haavikko), width of follicle (FW) and crown (CW) of M1inf were assessed.

RESULTS: The maturation of the first mandibular molar was delayed in both genders at 2 and 22 months of age. FW and CW were smaller in children with UCCLP at both 2 and 22 months of age. There was a positive correlation between maturation and FW.

CONCLUSIONS: Maturation of the first mandibular molar is delayed in both genders, and FW and CW were reduced in UCCLP compared to controls. Maturation was correlated with FW.