Use of mandibular chin bone for alveolar bone grafting in cleft patients / 대한악안면성형재건외과학회지

BACKGROUND: We evaluated and compared the outcomes of different ossification processes in patients with alveolar cleft in whom correction was performed using endochondral bone graft or intramembranous bone graft. METHODS: The patients were divided into two groups: the endochondral bone (iliac bone or rib bone) graft group and the intramembranous bone (mandibular bone) graft group. Medical records and radiologic images of patients who underwent alveolar bone grafting due to alveolar cleft were analyzed retrospectively. Through postoperative and follow-up radiologic images, the height of the interdental bone septum was classified into four types based on the highest point of alveolar ridge. Then, the height of the interdental bone septum and the area of the bone graft were evaluated according to the type of bone graft. In addition, the occurrence of complications and the need for an additional bone graft, the result of postoperative orthodontic treatment, and the eruption of impacted teeth were investigated. RESULTS: Thirty patients were included in this study. There was no significant difference in the change of the interdental bone height and the area of the bone graft according to the type of bone. There was no significant difference in the success rate of the surgery according to the type of bone. One patient underwent an additional bone graft surgery during the follow-up period. CONCLUSIONS: The outcomes of alveolar bone grafting were not significantly different according to the type of bone graft. If appropriate to the size of the recipient site, the chin bone is a useful graft material in alveolar cleft, as is the iliac bone.

The expression of pimonidazole hydrochloride(HP-1)in rat condylar cartilage in the early growth stage / 实用口腔医学杂志

Objective:To investigate hypoxia location in condylar cartilage in the early growth stage of rats.Methods:40 Sprague-Dawley rats were breastfed from 1 4 d to 21 d of age.1 0 rats were sacrificed at 1 2,24,48 and 96 h respectively after initiation of normal food at 21 d of age.The rats were administered pimonidazole hydrochloride (HP-1 )at a dose of 60 mg/kg by intraperitoneal injection 2 h before sacrifice.The expression of HP-1 in the whole condylar cartilage was detected by immunohistochemical staining.Results:HP-1 was mainly expressed in the chondrocytes of the fibrous and proliferative layer of cartilage,primarily concentrated in the weight-bearing area of joint-anterior aspect of the condyle and posterior aspect of the articular eminence at all time points.The highest expres-sion was observed at 24 h after initiation of normal food (P <0.01 ).Conclusion:In the early growth stage of rats,dietary loading may directly induce hypoxia in uper layer of condylar cartilage,the hyoxia level may change with time of dietary loading.

The Role of Microtubule in the Regulation of Endochondral Bone Formation in the Developing Mouse Cranial Base / 체질인류학회지

Endochondral bone formation of the developing cranial base is a complex process. This mechanism requires precise orchestration of many cellular events and cartilage matrix metabolism, such as proliferation, becoming round in shape, termination of proliferation, hypertrophic size-increase, and finally programmed cell death. Active formation and degradation of cartilage matrix take place, in which microtubules are involved for intracellular events; bone apposition follows these events. However, the involvement of microtubules during these changes in the developing cranial base has not been identified yet. Thus, we investigated the involvement of microtubules in the regulation of endochondral bone formation during cranial base development. Using tubulin-binding drug nocodazole, we examined the effects of altering the structure and function of microtubules during in vivo organ culture of the mouse cranial base. Cultured specimens were analyzed with HE staining, immunohistochemistry, and cell counting in order to study the morphological and molecular changes that occurred in the tissues. Disruption of the microtubular array by nocodazole reduced cells expressing proliferation marker Ki67, osteogenic marker BSP, and BMP4 within the sphenooccipital synchondrosis region; chondrocyte hypertrophy was ceased in the hypertrophic zone; degeneration of cartilage matrix and bone matrix apposition was inhibited in the ossification center of the basooccipital cranial base. Our data demonstrated that disruption of microtubules by nocodazole have multiple inhibitory effects on the sequential changes that occur during endochondral bone formation, suggesting the importance of normal microtubule-polymerization in cranial base development.

The study on the bone resorption rate after vertical alveolar ridge augmentation

< 0.05). Also significant difference is on volume resorption on two groups (P < 0.05). CONCLUSION: We found that more bone resorption occurred with iliac(endochondral) bone and when we use intraoral bone, that bone can maintain their vitality for alveolar ridge augmentation.

Effects of Changes in Mechanical Loading on Endochondral Bone Formation in Hindlimb-suspended Rats / 항공우주의학회지

BACKGROUND: To examine the effects of changes in mechanical loading on endochondral bone formation, a simulated rat model of weightlessness was introduced and the changes in the growth plate were evaluated. METHODS: Unloading condition on the hindlimb of Sprague-Dawley rats was created by fixing a tail and lifting the hindlimb. Six rats aged 6 weeks old were assigned to each group of unloading and reloading with their control group. Unloading was maintained for three weeks, and then reloading was applied for another one week afterwards. Histomorphometry for the assessment of vertical length of the growth plate, 5-bromo-2'-deoxyuridin (BrdU) immunohistochemistry for cellular kinetics, and biotin nick end labeling TUNEL assay for chondrocytes in the growth plate were performed. RESULTS: The vertical length of the growth plate and the proliferative potential of chondrocytes were decreased in the unloading group than those of the control group. Inter-group differences were more significant in the proliferative and hypertrophic zones. Reloading increased the length of growth plate and proliferative potential of chondrocytes as evidenced by the increase of the ratio of positive BrdU stained cells. However, the apoptotic changes in the growth plate were not affected by the alterations of the weight bearing. CONCLUSION: Alterations in the weight bearing induced changes in the chondrocytic proliferative potential of the growth plates and had no effect on the apoptosis occurrence. This may suggest that deprived weight bearing due to various clinical situations hamper normal longitudinal bone growth. Further studies regarding the factors for reversibility of chondrocytic proliferation upon variable mechanical stresses are needed.