AIM: to evaluate the local tolerance and efficiency of two experimental collagen matrices to increase the width of keratinized tissue.
METHODS: in 12 pigs, two apically positioned flaps were prepared on both sides of the mandible. The denuded defect areas were randomly covered with one of two experimental porcine-derived collagen matrices (M1; M2). The other defect area was left untreated (control). At 1 and 6 months, clinical measurements for the width and thickness of the keratinized tissue were recorded. At 6 months, all animals were sacrificed. Descriptive and semi-quantitative histologic analyses were performed. For statistical analysis, the Kruskal-Wallis test and the Mac Nemar test were applied.
RESULTS: the collagen matrices integrated well into the surrounding tissue without any signs of inflammation. The thickness and width of the keratinized tissue increased significantly over 6 months in all the groups, resulting in slightly more favourable results for M1 (compared with M2) with respect to the thickness and for M2 (compared with M1) with respect to the width of keratinized tissue. No statistically significant differences were observed for any of the evaluated clinical and histologic parameters among the three treatment modalities.
CONCLUSIONS: within the limits of this animal study, the prototype collagen matrices can be used safely to increase the width of keratinized tissue.