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Obliteration of the mastoid cavity has been realized with calcium phosphates associated to heterologous fibrin glue in otologic surgery. 22 artificially created epitympanic and 65 femoral defects in 22 rabbits were closed by means of dense or porous granulates of hydroxyapatite with homologous fibrin glue. Follow-up was for three weeks to 6 months. Osteo-integration of the implants was significantly delayed in the first weeks, comparing the integration of the same phosphates without fibrin glue.

Calcium phosphates have been proposed for obliteration of the mastoid cavity as well as TORP and PORP. Their use is based on a very good biocompatibility and host acceptance. The osseous integration of a dense and a porous hydroxyapatite is studied experimentally in artificially created epitympanic holes of rabbits. Osteoneogenesis was observed from the third week after surgery starting from the walls od the defects themselves. This had been evidenced using intravital fluorescent dyes. Porous granules showed more "osteoconductivity" in the beginning, probably due to their greater surface area. Bonding osteogenesis with both materials did not show differences after six months. No resorption was observed, excepting remodelation processes.

The techniques which pursue the closure of radical cavities include the use of local flaps as well as alloplastic material. Calcium phosphates are classified as "degradable" or "not degradable". The paper tries to offer an explanation why hydroxyapatite or tricalcium phosphate, mostly used calcium phosphates, may be include in both groups. The introduction in the use of alloplastic materials should serve as orientation for those who initiate and stimulate to revision of clinical results. The comparison of same calcium phosphates seems not to be possible as their preparation techniques may be completely different.