A Prospective Study of Chin Bone Graft Harvesting for Unilateral Maxillary Alveolar Cleft During Mixed Dentition

The chin is a common donor site for alveolar cleft bone grafting. The amount of bone available at this site can be limited, because conservative harvesting with mixed dentition must consider the incisive nerve, the unerupted mandibular canine, and the integrity of the inferior mandibular border.

Patients with nonsyndromic unilateral alveolar cleft in the mixed dentition stage were selected for this study. The volume of bone obtained from the mandibular symphysis (symphysis menti), degree of alteration in lower lip sensation, anterior tooth vitality, remaining bone in the alveolar cleft, and bone defects at the donor site 1 year after surgery were evaluated.

Eighteen patients were enrolled in this study. The mean volume of bone harvested from the symphysis was 2.1 mL (range, 1.6 to 2.3 mL). For all cases, the bone volume harvested from the symphysis was insufficient to fill the alveolar cleft defect, and allograft had to be added to completely fill the cleft. Allograft was admixed in the range of 0.5 to 1 mL with autogenous bone harvested from the mandible. Lower lip sensation and vitality of the anterior teeth of the mandible were within the normal range 1 year after surgery in all cases. Fourteen of 18 patients (77.8%) had normal bone height or bone height at least three fourths of the expected height in the grafted alveolar cleft after 1 year; only 10% of the defect remained in the mandible.

The amount of bone yielded by conservative monocortical bone harvest from the mandibular symphysis during the mixed dentition stage for unilateral alveolar cleft bone grafting is not sufficient in volume and should be mixed with allograft. However, donor site morbidity is low with this approach.