Healing of human critical-size alveolar bone defects secondary to cyst enucleation: a randomized pilot study with 12 months follow-up.

Background: Alveolar bone cyst enucleation can give rise to critical-size defects whose healing may be incomplete due to the loss of periosteum or bone walls and there is a paucity of studies investigating the use of immediate bone grafts. The aim of this study was to compare spontaneous healing versus a deproteinized bovine bone graft.
Methods: In this prospective randomized clinical pilot study, twenty patients requiring the removal of a cyst ≥20 mm in maximum diameter were randomly assigned to one of two groups: deproteinized bovine bone grafting (test) or spontaneous healing (control). Computed tomographies were obtained preoperatively and 12 months after surgery and the radiolucent volumes were compared. Residual radiological morphology and clinical outcomes at 7 days and 1, 6 and 12 months after surgery were also assessed.
Results: The median percentage reduction in the volume of the defect was 98% in the test group and 73% in the control group (P=0.001) with an evidence of soft tissue invagination in the latter. There were no differences in the clinical parameters between the two groups.
Conclusions: Within the limitations of this pilot study, the healing of critical-size alveolar bone defects is incomplete at 1 year observation and the use of deproteinized bovine bone graft did not influence the clinical outcomes.