Closure of palatal defects without a surgical flap: an experimental study in rabbits

This study evaluated the use of resorbable calcium sulfate with and without bone grafting in palatal defects in rabbits as a guide to regeneration of the mucoperiosteal tissue and bone.

Eighteen New Zealand rabbits were used in the experiment. A 1-cm wide region of mucoperiosteum, nasal mucosa, and bone between the incisor and premolar teeth was excised from the left side of the palate to create a defect. These gaps were left open and unfilled in 6 animals as a control (group 1). Defects in a second group of 6 animals were packed with calcium sulfate (group 2). The osseous defects in a third group of 6 animals were filled with bovine demineralized xenographic bone particles, and the soft tissue gaps were covered with calcium sulfate (group 3). The various sites were evaluated clinically at 1, 3, and 4 weeks, and then at 3 months after surgery. All animals were killed at the 3 months period, and the sites were evaluated histologically.

The calcium sulfate had resorbed and the mucoperiosteal margins of the defects in both experimental groups had regenerated and the soft tissue gaps were closed at 4 weeks. Osseous defects in group 3 showed complete bone regeneration compared with osseous defects in group 2. Defects in the control group showed persistent oronasal fistulae and fibrous healing.

Open mucoperiosteal wounds in rabbits packed with calcium sulfate can heal uneventfully, and the gaps can be closed successfully.