Influence of a collagen membrane positioned subjacent the sinus mucosa following the elevation of the maxillary sinus. A histomorphometric study in rabbits.

Abstract

To evaluate the healing after elevation of the sinus mucosa when a collagen membrane was placed between the sinus mucosa and a xenograft used as filler. Eighteen rabbits were used. Sinus mucosa elevation was performed bilaterally, and a collagen membrane was applied subjacent to the sinus mucosa only at a randomly selected test site. At both sites, a collagenated corticocancellous porcine bone was placed within the elevated space and the access window was covered with a collagen membrane. The animals were sacrificed after 2, 4, and 8weeks of healing, six animals for group. Ground sections were prepared. At the histomorphometric evaluation, the elevated area after 2 and 8weeks was 11.8 and 8.8mm2 at the test, and 10.0 and 5.3mm2 at the control sites, respectively. The available area was obtained subtracting the remaining area occupied by the membrane from the elevated area and, after 8weeks, was 6.7±0.9mm2 . After 8weeks of healing, the mineralized new bone within the elevated space was 18.2±5.5% at the test and 26.7±7.7% at the control sites. Within the available space at the test site, the percentage was 27.3±7.0% after 8weeks of healing. At 2 and 8weeks of healing, within the elevated space, the xenograft proportion was 30.9±4.4% and 6.9±2.8% at the test, and 35.2±7.3% and 9.6±4.9% at the control sites, respectively. The placement of a collagen membrane subjacent the sinus mucosa did not reveal any major morphometric difference. The collagen membrane was not completely resorbed after 8weeks.