Duplicate sections of peri-impant bone were obtained from each implant sample to evaluate the percentage of stained areas in order to differentiate markers of collagen I and osteocalcin within both experimental conditions (Fig. 6). The highest collagen I expression values were observed at the IR experimental condition, and osteocalcin expression was higher at the 9M.

There was a statistically significant difference between the two experimental specimens (9M and IR) in immunohistochemical evaluation for osteocalcin expression (Tables 3 and 4). Immunohistochemical analyses allowed to identify manifestation of osteocalcin protein in all thirds of peri-implant bone in both models evaluated, with greatest expression to model which the healing time was higher (9M). Statistical difference presented was observed especially in the middle and lower thirds. The first third presented a difference, but it was not significant. The evaluation of collagen I expression did not show statistical differences. In all evaluated thirds, the presence of the protein was equivalent.