Patterns of tooth agenesis in patients with orofacial clefts.

Orofacial clefts are a common oral disorder associated with tooth agenesis. As information on the simultaneous absence of teeth can be an aid in treatment planning, a large sample of orofacial cleft patients was examined. The sample consisted of 910 patients with cleft lip and palate. Tooth agenesis was assessed on the basis of at least two panoramic radiographs and patient records. Third-molar agenesis was determined in 474 patients. Patterns of tooth agenesis were analysed using Tooth Agenesis Code (TAC) values, according to VAN WIJK & TAN. Per quadrant, at least 90% of patients could be described according to three different patterns. In the maxilla, 85% of patients with tooth agenesis had a TAC-value of 2, 16, or 18 on either the left side, right side or bilaterally. In the mandible, 90% of patients with tooth agenesis had a TAC-value of 16, 1 or 2 on either the left side, right side or bilaterally. In patients with tooth agenesis, patterns were symmetrical in the maxilla in 18.8% and in the mandible in 51%. More extended cleft types were associated with a higher prevalence of tooth agenesis. Third-molar agenesis (prevalence = 22.4%) was significantly related to the prevalence of other absent teeth. These results show which patterns of tooth agenesis can be expected to occur in most orofacial cleft patients.