Initial tissue response to anti-washout apatite cement the rat palatal region: Comparison with conventional apatite cement

Initial tissue response to anti-washout apatite cement (aw-AC) in the palat al region was studied. Conventional apatite cement (c-AC) was employed as a control material. Bone defects generated in the rat palatal region, where complete hemostasis is difficult to effect, were filled with both cement ty pes and examined histologically for up to 8 weeks. At 1-week postfilling, a portion of the c-AC had washed out, resulting in slight inflammation and s evere foreign-body response. The degree of foreign-body response to c-AC wa s reduced over time; however, foreign-body response continued to be in evid ence 8 weeks after surgery. As a result, poor bone formation was observed i n the case of c-AC at 8 weeks post-surgery. In contrast, aw-AC set well, ma intained its shape at implantation, and caused little foreign-body response . Osteoblasts were observed at 2 weeks following surgery. Moreover, the bon e defect was completely covered with new bone at 8 weeks post-surgery. This observation suggests that aw-AC may be used without corn plication in case s where complete hemostasis is difficult to achieve, that is, where the use of c-AC is contraindicated. (C) 2001 John Wiley & Sons, Inc.