Implants Osseointegration in Bone Defects Treated with Latex Angiogenic Protein

Objective: The aim of this study was to evaluate the osteogenic capacity of latex (Hevea brasiliensis) angiogenic proteins to improve dental implants osseointegration when placed in experimental critical bone defects in dog mandibles.

Methods: Four defects were trephined (5.0 mm long X 6.3 mm wide) on each side of the mandible of six Mongrel dogs twelve weeks after teeth extractions. Thirty six implants TiUnite MK3 Nobel Biocare® (10.0 mm long X 3.3 mm wide) were placed in the center of the defects. The circumferential gaps around the implant were filled either with particulate autogenous bone graft; latex angiogenic protein mixed in a gel carrier; or left without treatment (sham). As a control, twelve defects were filled out with carrier without latex angiogenic protein or implants. Circumferential defects were covered with non-resorbable e-PTFE Gore Tex® membrane at one side and left uncovered on the other. Ground sections of the implants, circumferential defects and surrounding tissues were prepared from biopsies taken at 4 and 12 weeks post-operative and stained with Stevenel's blue and Alizarin red. Measurements of bone-implant contact (BIC), bone area between implant threads (BA) and bone area in a rectangle (BAR) were performed. Data were analyzed statistically using two-way ANOVA with Tukey pos-test.

Results: The outcomes of histomorphometry showed higher BIC and BA for implants placed in latex protein sites covered with non-resorbable membrane after 4 weeks (p<0.05), when compared with other experimental adjunctive therapies. After 12 weeks no difference among the groups could be found either for BIC, BA or BAR (p>0.05).

Conclusion: These data indicated that latex angiogenic proteins covered with non-resorbable membrane used in critical bone defects around implants supports osteogenesis at an early stage of bone tissue healing. (This research was supported by grants from FAPESP # 06/04359-0 to SPX and # 06/58059-7 to MFMA).