Pattern of clefts and dental anomalies in six-year-old children: a retrospective observational study in western Norway.

OBJECTIVES: Clefts of the lip and/or palate (CL/P) are the most common congenital disorders of the head and neck. In Norway, the incidence is 1.9/1000 live births. The aim of this study was to investigate the frequency and distribution of various types of clefts and dental anomalies in patients treated by the cleft lip and palate (CLP) team in Bergen, Norway. MATERIAL AND METHODS: The material comprised the records of patients 6 years of age, examined by the CLP team in Bergen from spring 1993 to autumn 2012, incomplete records were excluded. The records of 989 patients were analysed, using frequencies and Chi-square test to compare differences in percentages between groups. RESULTS: The gender distribution was 58.8% male and 41.2% female. Isolated cleft palate (CP) was the most common condition (39.5%). Clefts of the lip, jaw and palate (CLP) constituted (30%) of cases and (30.5%) had isolated cleft lip (CL). The frequencies of agenesis, supernumerary and peg-shaped teeth were (36.5%), (17.8%) and (7.5%), respectively. Over 50% of the study population were diagnosed with one or more malocclusion. Of the CLP patients, 61.4% had Angle Class III occlusion. Statistical analysis disclosed a positive association of agenesis with Class III occlusion (OR =1.8, p</= 0.001). CONCLUSIONS: The findings supported the hypothesis that the distribution of dental anomalies and occlusal disorders varied among patients with CL, CP and CLP. In patients with cleft, there is a twofold chance to get Class III malocclusion in the presence of agenesis.