Abstract: Objective: To study the alveolar bone thickness and height of patients with unilateral cleft lip and palate (UCLP) using cone-beam computed tomography (CBCT). Methods: The CBCT scans of 30 patients with UCLP were assessed. The thickness and height of alveolar bone surrounding the maxillary central incisors and canines were measured using the software Invivo. For each tooth analyzed, the thickness of the buccal and palate bone level at 3mm, 6mm, and 1mm were measured. Meanwhile, we measured the distance between the bone crest (AC) and the cementoenamel junction (CEJ) at the buccal and palate side. A paired t-test was performed to compare bone thickness and AC-CEJ distance at the cleft and non-cleft side of the central incisors and canines. Results: For central incisors, the thickness of the buccal and palate bone level at 3mm and 6mm had statistical difference between the cleft side and non-cleft side (P<0.05). The thickness of alveolar bone at the non-cleft side was larger than that at the cleft side. But for canines, the thickness of the buccal and palate bone had no statistical difference between the cleft side and non-cleft side. For both central incisors and canines, the AC-CEJ distance of the buccal bone had statistical difference between the cleft side and non-cleft side (P<0.05). The AC-CEJ distance at the cleft side was larger than that at the non-cleft side. The AC-CEJ distance of the palate bone had no statistical difference between the cleft side and non-cleft side. Conclusion: For UCLP, the teeth alveolar bone loss and thickness are both in relation to the existence of cleft. It is necessary to accurately assess the alveolar bone by CBCT before orthodontic treatment.

Key words: Unilateral cleft lip and palate, Teeth alveolar bone, Cone-beam computed tomography