Emergence of the deciduous incisors in CLP children.

A longitudinal study of the time of emergence of the deciduous incisors was performed in Dutch cleft lip and/or palate (CLP) children (n = 52). A group of normal children (n = 62) served as control. Emergence dates were registered by the parents and checked regularly by one of the investigators. Mean emergence times of the deciduous upper incisors--including both the cleft-sided lateral in the distal segment and in the premaxilla--and lower incisors were studied. The lateral incisor on the cleft side situated in the distal segment was delayed 8 months in children with a cleft lip and alveolus and 13 months in cleft lip and palate children. The delay for the lateral incisor situated in the premaxilla increased by nearly 4 months in these children. The upper lateral incisors on the non-cleft side and in cleft palate children were not delayed as compared with normal children. The central lower incisors emerged one month earlier than normal when there was a palatal cleft. Presurgical orthopaedics used in these groups could have caused this acceleration. The central upper and lateral lower incisors showed no significant differences in mean emergence ages as compared with the control group, nor between the various cleft types. Sex differences were not found in any of the groups.