The effect of permanent grafting materials on the preservation of the buccal bone plate after tooth extraction: an experimental study in the dog.

OBJECTIVES: The aim of the present study was to evaluate the effects of a novel bone substitute system (Natix(®)), consisting of porous titanium granules (PTG) and a bovine-derived xenograft (Bio-Oss(®)), on hard tissue remodelling following their placement into fresh extraction sockets in dogs. MATERIAL AND METHODS: Six modalities were tested; Natix(®) granules with and without a covering double-layered Bio Gide(®) membrane; Bio-Oss(®) with and without a covering double-layered Bio Gide(®) membrane; and a socket left empty with and without a covering double-layered Bio Gide(®) membrane. Linear measurements, indicative of buccal bone height loss, and an area measurement indicative of buccal bulk bone loss were made. The statistical analysis was based on the Latin Square design with two blocking factors (dog and site). Tukey's post hoc test was used to adjust for multiple comparisons. RESULTS: Histological observation revealed that while bone formed around both the xenograft and the titanium particles, bone was also noted within titanium granules. Of the five modalities of ridge preservation techniques used in this study, no one technique proved to be superior. CONCLUSION: The titanium granules were observed to have promising osseoconductive properties.

Evaluation of New Bone Formation and Osseointegration Around Subperiosteal Titanium Implants with Histometry and Nanoindentation.

PURPOSE: To assess the quality and quantity of newly formed bone around rough-surfaced titanium subperiosteal implants stabilized with two different fixation techniques and to investigate nanoindentation as a method for measuring the elastic properties of the bone around these implants. MATERIALS AND METHODS: Ten 6-month-old white rabbits were used in this study. One femur received a subperiosteal implant fixed to the bone with screws. The other femur received a subperiosteal implant stabilized with a trough (bed) in the bone area, plus fixation screws. After a 3-month healing period, the animals were sacrificed and each titanium plate was resected along with the surrounding bone. Histometric measurements of osseointegration were performed on 16 titanium plates, and 16 titanium plates were evaluated qualitatively (hardness and modulus of elasticity) with nanoindentation. A regression model was used to analyze the data. RESULTS: Subperiosteal implants placed into a trough performed significantly better than those placed on top of the cortical bone in terms of percentage of bone in direct contact with the titanium plate, length of new bone, and percentage of area of new bone. The mechanical properties (modulus of elasticity, hardness) of the newly formed bone above the plate measured at the microstructural level were significantly inferior to those of the mature cortical bone below the plate. CONCLUSION: Subperiosteal implants placed into a trough performed better than those placed on top of the cortical bone, but it seems that 3 months of healing is not enough to achieve optimal integration and bone maturation around them. Nanoindentation can offer valuable insight into the elastic properties of the microstructural component of the bone.