Assessment of dental arch relationships in Japanese patients with unilateral cleft lip and palate

Objective: Evaluation of the dental arch relationships of Japanese patients with unilateral cleft lip and palate (UCLP) from the orthodontic clinic of the University of Tokyo Hospital (UTH) compared with patients treated by the Oslo Cleft Team, Norway. Design: Retrospective study and comparison with previous reports. Materials: Dental models of 24 patients with UCLP in UTH taken before orthodontic treatment and before alveolar bone grafting were included. Surgeons in many hospitals performed primary surgeries. These models were matched for age and gender with 24 models from a consecutive series of patients treated by the Oslo Cleft Team as part of the Eurocran Good Practice Archive. A total of 48 models were evaluated. Main Outcome Measure: Dental arch relationship was rated with the Goslon Yardstick. The strength of agreement of rating was assessed with weighted kappa statistics. Results: Intra- and interexaminer agreements evaluated by weighted kappa statistics were high, indicating good reproducibility. Almost 60% of the patients in UTH were classified into poor or very poor categories, and the mean Goslon score was 3.50. These results show a contrast to those in Oslo and were the poorest in comparison with previous reports. Conclusion: Dental arch relationships in patients with UCLP in UTH were poor. This seemed to be attributable to surgical procedures, but a factor of racial difference in the craniofacial morphology was also considered. Further intercenter research is required to clarify this point.