Injectable calcium phosphate cement as a graft material for maxillary sinus augmentation:: an experimental pilot study

Objectives: The aim of the present study was to evaluate the efficiency of injectable CaP cement as a graft material around dental implants in the maxillary sinus augmentation procedure. Material and methods: Bilateral sinus augmentation process was carried out in three sheep and two implants were inserted during the same session. Out of a total of 12 installed implants, eight belonged to the so-called experimental group. In the experimental group, injectable CaP cement was used as augmentation material while autologous bone served as control. Results: Histological examination revealed that newly formed bone surrounded the cement completely without an intervening fibrous tissue layer. Following a healing period of 12 weeks, mean bone-to-implant contact (BIC) values in the experimental and control groups were 36 +/- 5 and 37 +/- 3, respectively. The percentage of BIC was comparable with other experimental sinus augmentation studies. Further, it appeared that the thickness of the cortical bone that covered the outer surface of the maxillary sinus was < 2-3 mm, which affected the primary stability of the implants negatively. Conclusion: CaP cement is indeed effective to stimulate bone formation in the sinus elevation procedure. Nevertheless, additional improvements in the cement composition are required to allow final clinical utilization of the material.