Bone Defects In Group Research Articles

Spontaneous Bone Regeneration in Surgically Induced Bone Defects in Young Rabbits

Defects of the femoral shaft (15%, 20%, 25%, and 30% of the femoral length) with intact periosteum were made in young rabbits to investigate differences in union time. The mean union time was 7.3, 7.1, 7.4, and 7.0 weeks, respectively and there was no significant difference (P >0.05) between the groups. The mean healing indices were 6.7, 4.6, 3.9, and 3.1 weeks/cm, respectively and these were significantly different (P <0.05) between the 15% bone defect group and the other bone defect groups. These results suggested that union time was not affected by the amount of bone defect. Femoral lengthening of 20% was performed to compare the quality of callus with those of the femoral defect of 20%. The mean healing indices of defect and lengthening were 4.6 and 5.7, respectively and the difference was significant (P = 0.004). The callus stiffness of femoral defect was higher (P = 0.02) than that after femoral lengthening whereas the bone mineral density of the callus showed no significant difference (P = 0.37) between two groups. The method of filling bone defect with callus generated from the intact periosteum may be a new therapeutic option for the reconstruction of large bone defects in children when other treatments are not available.

High bioactive material-bone graft in bone defect healing

OBJECTIVE: To assese the value and clinical significance of bioactive material-hydroxyapatite (HA) combined with TGF-beta1 in bone defect healing. METHODS: The applicability of bioactive material-HA granules combined with TGF-beta1 (group A) as a substitute for bone graft was observed in SD rat model. The results were compared with those of HA granules (Group B) and ungrafted bone defect (Group C). RESULTS: Group A demonstrated the highest level of type I collagen mRNA during healing period. CONCLUSION: The bioactive material-HA combined with TGF-beta1 can efficiently bond to ongrowing new bone comparing to HA granules.

骨補填材（ＨＡＰ・ＴＣＰ複合体）の組織親和性

Twelve white adult rabbits weighing 3000-4000 grams were used in this study. They were anesthethized with i. v. sodium pentobarbital.In one group, non-intracranially penetrating bone defects (about 5.0×5.0×1.5mm) were made in the frontal bone bilaterally. Hydroxyapatite and tricalciumphosphate composite (HTC) plugs of the same shape and size as the defects were inserted and covered with pedicled periosteum, free periosteum, or soft tissue only. Specimens of tissue were collected for histopathological examination 3 months later. The specimens were cut into 10μm thick sections and stained with hematoxylin and eosion for light microscopic studies.In the second group, HTC plugs of the same size (about 5.0×5.0×1.5mm) were placed on the frontal bone (onlay grafting) and covered as in the first experiment and examined in the same way.Macroscopic and microscopic examinations revealed firm contact between bone and HTC in all of the first group (bone defect group) and in the bones covered by pedicle periosteum in the second group. Firm contact between periosteum and HTC was observed in both groups. No infection or foreign body reaction occured. Three monthes later no invasion of osteoblasts from bone to composite was observed.Our results suggest that HTC has excellent and reliable biocompatibility with bone and periosteum.

顎骨病変の病態ならびに治癒過程における二重エネルギーＸ線吸収測定法による骨塩定量に関する研究 犬下顎骨骨欠損治癒過程における骨回復量について

A study was carried out by dual energy X-ray absorptiometry in the bone defects of sixteen beagles to determine the bone mineral content (BMC) and density (BMD) of the mandibular premolar region. Both shallow and deep defect groups which were obtained from the excised mandibles were measured on the onset as well as the 4th, 8th, and the 24th weeks after the operation. These were then compared with the values obtained by the intact opposite side to confirm the bone recovery rate.In the shallow bone defect group, the ratio of BMC to control decreased gradually from 95.1% to 82.4% over a period of 24 weeks, then the BMD ratio showed almost equal quantities of the control at all times. In the deep bone defect group, the BMC ratio increased from 52.4% to 89.8% in the first 4-week interval, followed by a decreasing change that resulted in 82.7% at the 24 weeks. The BMD ratio of the deep defects increased from 82.5% to 97.6% in the first 4 weeks, and thereafter that showed the same level as the control side.The bone mineral change was influenced by the depth of bone defects. BMC was a sensitive parameter to the regeneration of the bone defects, however, BMD was affected by only the deep defects. At the end of the observation period, BMC of both shallow and deep defects showed a regular level in contrast to the control side.

Possibility of connective tissue reattachment following mucoperiosteal flap surgery with full gingival retention in monkeys (author's transl)

The purpose of this study was to evaluate the height of connective tissue reattachment from the bone margin after flap operation in monkey. 3mm or 1.5mm of crestal bone was horizontally removed at buccal and interproximal areas, and root planing was carried out completely. For a histological land mark, a notch was prepared on the root surface at the bottom of bone defect. Ten weeks after operation, the monkey was sacrificed. The periodontal tissues of 40 teeth in two monkeys were observed histologically. During ten weeks, efforts were made to keep oral hygiene as clean as possible.The results which were obtained are as follows:1) At molar areas which had slight gingival inflammation, connective tissue reattachment was clearly found. In the 3mm bone defect group, it was 2.22mm (S. D. 0.60), and in the 1.5mm bone defect group it was 1.56mm (S. D. 0.70). The mean amount of new cementum in the 3mm bone defect group was 1.06mm (S. D. 0.54), and in the 1.5mm bone defect group it was 1.00mm (S. D. 0.80).2) At incisor areas which showed moderate gingi val inflammation caused by narrow attached gingiva, good connective tissue reattachment could not be obtained. In such areas, epithelial proliferation to apical site was found, but it stopped at the area where new cementum formation occurred. The mean amount of connective tissue reattachment was 0.90mm (S. D. 0.74) in the 3mm bone defect group and 0.85mm (S. D. 0.82) in the 1.5mm bone defect group. The mean amount of new cementum was 0.61mm (S. D. 0.39) in the 3mm bone defect group and 0.49mm (S. D. 0.39) in the 1.5mm bone defect group.3) The mean amount of alveolar bone loss at molar and incisor areas was 0.11mm (S. D. 0.39) in the 3mm bone defect group and 0.35mm (S. D. 0.35) in the 1.5mm bone defect group respectively.