**Acknowledgements**

statistically significant in none of the time intervals. Histologic section yielded a core material was left non-resorbed right at the center of the defect. Ooms et al. [19] in a study on dog, placed an injectable porous form CaP graft material into the standardized defects in combination with an experimental titanium implant and found that this material was highly ossified in the whole area, especially in infection cases or in case of few walled bony defects, and also he found out that the material outcome might be high if vascularization is supported. It may be proposed that further porosity is required around the iCaP to allow vascularization and body-fluid

Many different attempts and experiments have been performed in a purpose to increase the biodegradation of CaP cement. It is thought that increasing the solubility of CaP inside the bone results in accelerating the period of biodegradation. Solubility increases in direct proportion to the surface area [20]. The body fluids and their contents such as phagocytic cells expedite the resorption period of the graft when the contact area between the fluids and the graft material increases. As a result, the hardened graft material porosity is expanded so to rise the infiltration of fluids and blood between the graft. Daculsi et al. [21] produced a porous CaP cement with interporous distance ranges between 100–500 micrometer to introduce a good

In the present experimental model, new bone regeneration was ascertained without any complications that might occur thereby of using a barrier membrane such as exposure of the soft tissue and infection. This may be attributed to site of the tibia as the area of the defect. Nonetheless, applying the graft into the oral bone might also have good prognosis with no complications as it was observed in the tibia. Some researchers reported that the use of membrane may be unnecessary as the material acts as a space maintainer. In this study, the four-walled bony defect was involved so that no barrier membrane was used. Hence, new

The injectable CaP cement has an excellent biocompatibility and a good space maintaining ability. No pathologic findings encountered during the period of the present and similar other studies. Injectable from of the CaP greatly improves the applicability of the material. However, the biodegradation of the present iCaP was similar to those of previous observations. The application of the CaP yielded better new bone formation as compared to the empty control defects. The center of the graft seen intact at the end of 12 weeks. The inclusion of a hemihydrate component did not effect effected neither the new bone formation nor the residual graft. In both groups and time intervals, in the injectable CaP was not degraded completely at the end of 12 weeks of recovery time. Supplementary methods are required to fasten the

penetration.

186 Dental Implantology and Biomaterial

environment for cell growth.

**5. Conclusions**

biodegradation process.

bone formation was occurred in both groups.

The author thanks Dr. Ata Anıl and Dr. Jakob Wenz for the preparation of the iCaP. Dr. Joop Wolke is acknowledged for the histologic assessment. Dr. Sevda Özel is acknowledged for the statistical analysis of this study. This study was supported by the Turkish Society of Oral Implantology and Istanbul University Research Fund.
