Obliteration of temporal dorsal bulla in guinea pigs using different types of calcium phosphate.

Objective: The purpose of this study was to evaluate the applicability of different calcium phosphate types after mastoid obliteration procedure using the guinea pig as an animal model.

Materials And Methods: Twenty six male guinea pigs were used for the experimental study. Four guinea pigs were used as a normal control group, with the remaining used for the experimental group. After bulla mucosa was removed, non-obliterated ears were used as control and granular (Polybone-G) or powder (Polybone-P) types of Polybone (tricalicium phosphate and polyphosphate) were applied into the dorsal bulla. The radiological and histologic findings were obtained from each animal at 8 and 20 weeks after obliteration.

Results: On radiological examination, thickening of the bulla wall observed in all experimental groups compared with normal group. Increased homogenous bony densities continuous with the bulla wall were observed in the Polybone-G group compared to the other experimental groups, and some isolated bony densities were observed in the Polybone-P group. Histopathologic findings showed increased new bone formations and less inflammatory reactions in the Polybone-G group compared to the Polybone-P group.

Conclusion: This study demonstrates that granular type calcium phosphate can be used as effective material than powder type in mastoid obliteration.