Histological and histomorphometric study of human palatal mucosa : Implications for connective tissue graft harvesting.

AIMS: To analyze the histologic structure and histomorphometric characteristics of human hard palatal mucosa in order to determine the donor site of choice for connective tissue grafts from a histological point of view.

MATERIAL AND METHODS: Palatal mucosa samples from six cadaver heads were harvested at four sites: incisal, premolar, molar and tuberosity. Histological and immunohistochemical techniques were performed, as was histomorphometric analysis.

RESULTS: In the current study we found that the density and size of cells was higher in the superficial papillary layer, whereas the thickness of the collagen bundles increased in the reticular. Excluding the epithelium, the mean percentage of lamina propria (LP) and submucosa (SM) were 37% and 63%, respectively (p<0.001). LP thickness showed similar values in incisal, premolar and molar regions, and a significantly greater thickness in tuberosity (p<0.001). The thickness of SM increased from incisal to premolar and molar, disappearing in the tuberosity (p<0.001).

CONCLUSION: As dense connective tissue of LP is the tissue of choice for connective tissue grafts, the best donor site from a histological point of view is the tuberosity, because it is composed only of a thick LP without the presence of a loose submucosal layer.