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

ObjectiveThe 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 methodsTwenty 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.ResultsOn 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.ConclusionThis study demonstrates that granular type calcium phosphate can be used as effective material than powder type in mastoid obliteration.