ABSTRACT
The bone graft materials can be grossly divided into autogenous bone, allogenic bone, xenogenic bone, and alloplastic material. Much care was given to other bone graft materials away from autogenous bone due to its additional operation for harvesting, delayed resorption and limitation of quantity. Demineralized freeze-dried bone(DFDB) and hydroxyapatite are the representatives of bone graft materials. As resorbable hydroxyapatite is developed in these days, the disadvantage of nonresorbability can be overcome. So we planned to study on the strength and the bone formation at the rats calvarial defects of DFDB graft and those of the composite graft with DFDB and resorbable hydroxyapatite. We used the 16 male rats weighting range from 250 to 300 gram bred under the same environment during same period. After we made the 6mm diameter calvarial defect, we filled the DFDB in 8 rats and DFDB and resorbable hydroxyapatite in another 8 rats. We sacrificed them at the postoperative 1 month and 2 months with the periostium observed. As soon as the specimens were delivered, we measured the compressive forces to break the normal calvarial area and the newly formed bone in calvarial defect area using Instron (Model Autograph S-2000, Shimadzu, Japan). The rest of the specimens were stained with H&E(Hematoxylin & Eosin) and evaluated with the light microscope. So we got the following results. 1. In every rats, there was no significant difference between the measured forces of normal bone area and those of the bone graft area. 2. In 1 month, the measured forces at DFDB graft group were higher than those of the DFDB and resorbable hydroxyapatite composite graft group(P<0.05). 3. In 2 months, there was no significant differences between the measured forces of DFDB graft group and those of the DFDB and resorbable hydroxyapatite composite graft group. 4. In lightmicroscopic examination, most of the grafted DFDB were transformed into bone in 1 month and a large numbers of hydroxyapatite crystal were observed in DFDB and resorbable hydroxyapatite composite graft group in 1 month. 5. Both group showed no inflammatory reaction in 1 month. And hydroxyapatite crystals had a tight junction without soft tissue invagination when consolidated with newly formed bone. 6. In both groups, newly formed bone showed the partial bone remodeling and the lamellar bone structures and some of reversal lines were observed in 2 months. From the above results, it is suggested that DFDB and resorbable hydroxyapatite composite graft group had a better resistance to compressive force in early stage than DFDB graft group, but there would be no significant difference between two groups after some period. And it is suggested that the early stage of bone formation procedure of DFDB and resorbable hydroxyapatite composite graft group was slight slower than that of DFDB graft group, but there would be no significant difference between two groups after some period.
Subject(s)
Animals , Humans , Male , Rats , Bone Remodeling , Durapatite , Osteogenesis , Tight Junctions , TransplantsABSTRACT
Subject(s)
Allografts , Biology , Bone Transplantation , Fruit , Physiology , Tissue Banks , Transplantation ImmunologyABSTRACT
Subject(s)
Female , Humans , Male , Congenital Abnormalities , Dentofacial Deformities , Epidemiologic Studies , Hypertrophy , Orthognathic Surgery , Osteotomy, Sagittal Split Ramus , Prognathism , Retrospective StudiesABSTRACT
Sixty mongrel dogs were divided into three groups of twenty dogs. One group of twenty dogs underwent placement of a rigid reconstruction plate (2.7mm thickness of plates and 3.0mm diameter of screws, Richards plating system, stainless-steel) and labeled normal mandibles stress shielded (NMSS) group. Another group of twenty dogsundeuuent cancellous cellular bone grafts of 3.5cm in length and a rigid reconstruction plate. In this group the plates were left in place until the time of sacrifice(1460 days) The group was labeled as a bone grafted mandibles stress shielded (BGSS). Ten dogs of each group were sacrificed at day 60. Another ten dogs of cach group were sacrificed at day 1460. In addition, all intitial resection specimens were processed for histomorphometry on trabecular bone area(TBA) as a normal non-stress shielded reference value of day-0 control (NMNSS) group. The histomorphometric results are as follows. Average percentage of TBA at day 0 control in NMNSS group was 44+/-5%. Average percentage of TBA in NMNSS group at 60 days was 42+/-6% , and that at 1460days was 42+/-4%. Average percentage of TBA in NMSS group at 60days was 47+/-6%, and that at 1460days was 44+/-4%, while average percentage of TBA at day 0 control was 44+/-5% (pinot available). Average percentage of TBA in BGNSS group at 60 days was 67+/-4, and that at 1460 days was 65+/-4%, while average percentage of TBA in day o control was 44+/-5%. BGNSS group shows, once each mandible was bone grafted at 60 days, that bone density was increased due to the high cellular bone grains. But after 1460 days there are little significant change, and that they are stable for four years(p<.001). Average percentage of TBA in BGSS group at 60 days was O+/-6, and that at 1460 days was 66+/-4% , while average percentage of TBA at day O control was 44+/-5%. BGSS group with the plate left in place for 4 years also shows the enhanced bone trabecular percentage at 60 days due to the high cellular bone grafts, but after 60 days until 4 years still little significant change(p<.001). The result data indicates the stress shielding from the rigid reconstruction plate on the mandible is not valid. It is suggested that clinicians do not need to remove reconstruction plates for fear of stress shielding.
Subject(s)
Animals , Dogs , Bone Density , Edible Grain , Mandible , Reference Values , TransplantsABSTRACT
Subject(s)
Anti-Bacterial Agents , Copper , Disinfection , Ethylene Oxide , Fibroblasts , Freezing , Micropore Filters , Sterilization , Succinate Dehydrogenase , TransplantsABSTRACT
No abstract available.
ABSTRACT
No abstract available.