Effect of ultrasound-facilitated fixation on oral mucosa density and morphology

We investigated the effects of ultrasound-facilitated fixation on oral mucosal morphology. Bovine dorsal tongue and porcine buccal (cheek) mucosa were sonicated for 0, 5, 10 or 15 min in a modified methacarn fixative, then incubated at 25° C for 4 h. Initial mass, volume and density of each specimen were measured before and after treatment and fixation. Morphometric analysis of the scanning electron micrographs was used to quantify changes in mucosal structure and microtexture. Statistical methods were used to describe the relation between sonication time, tissue density and relative change in tissue density. Our results indicate a linear correlation between sonication time and density of the dorsal tongue specimens. The treatment caused contraction of the tongue tissue and expansion of the buccal mucosa. Differences between initial and final tongue densities and the relative change in tissue density of the tongue vs. buccal mucosa were statistically significant. Differences observed between initial and final buccal mucosa densities were not statistically significant. Changes in buccal mucosa density correlated inversely with sonication time by contrast to the tongue density, which was correlated directly with this factor. Our study illustrates that while preservation of mucosal morphology and biopolymers can be achieved by ultrasound-facilitated fixation, its effects on tissue density are both time-dependent and specific to certain regions of the mouth.