• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.2
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• pp.203-220
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• 1991

The purpose of this study was to investigate the changes of morphology and structure of bone tissue, caused by administration of high-dose hydrocortisone, elcatonin and cyclophosphamide. In order to carry out experiment, 60 four-week old Sprague-Dawley strain rats weighing about 107 gms were selected and divided into experimental group and control group. The experimental group was subdivided into three groups, assigned fifteen rats for each group, by the different drugs administered. Each experimental group was then categorized as follows: hydrocortisone 30㎎/㎏ b.w. with daily subcutaneous injection, elcatonin 20U/㎏ b.w. with daily subcutaneous injection, and cyclophosphamide 100㎎/㎏ b.w. with a single intraperitoneal injection. Fifteen rats were injected daily with 5㎖/㎏ b.w. of normal saline solution subcutaneously in control group. Rats in control group and experimental group were serially sacrificed on the 6th, the 15th and the 22nd day after injection of normal saline, hydrocortisone, elcatonin and cyclophosphamide, respectively. Being sacrificed, both sides of mandibular condyles were removed and fixed with 10% neutral formaline. The one side of mandibular condyles was radiographed with soft X-ray apparatus. Thereafter, the obtained radiographs were observed, and the bone density of condylar head and condylar neck regions was measured by use of transferring video-based digital radiograph. The other side was further decalcified and embedded in paraffin as usual manner, then sectioned and stained with hematoxylin and eosin, observed by light microscope. The obtained results were as follows: 1. Sclerotic changes with regularly increased trabecular pattern were seen throughout experimental periods in hydrocortisone group. Increased the number of trabecular pattern with irregularity and periodic striation on the periphery of condylar head region were appeared with lapse of time in elcatonin group. In cyclophosphamide group, irregular trabecular pattern and stippled radiopacities on mandibular condyle were observed with lapse of time. 2. The bone density of condylar head region was increased in hydrocortisone group, decreased in elcatonin group, and tended to be decreased in cyclophosphamide group, compared with that of control group according to the experimental periods. 3. The bone density of condylar neck region tended to be rather increased in hydrocortisone group, elcatonin group and cyclophosphamide group, depending on the experimental periods. 4. In microscopic studies, there were irregular trabecular bonds and osteoblastic activity in hydrocortisone group and elcatonin group throughout experimental periods, degenerative cartilage and trabecular bones in the 6th day and densely calcified trabecular bones in the 22nd day in cyclophosphamide group.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.11 no.1
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• pp.50-62
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• 1989

This is clinicostatistical study of mandibular fractures. This study was based on a series of 677 patients with mandibular fracture during the period of 1982 to 1987. This results obtained were as follows : 1. In respect of incidence, there were high frequency in May and September, and in large city(63%). 2. The age frequency was the highest in the 20s-year old group (38.7%), and the ratio of male to female was 4.64 : 1. 3. The most common etiologic factor was blow(31.5%), but in children that was traffic accident followed by fall down. 4. The most common site of bone fractures was symphysis, followed by angle, condyle. In comparison of right and left sides, left side was more frequently involved(364 cases) than right side(257 cases). 5. The patients arrived in hospital immediately within 24 hours after accident were 62.9% of all, and 42.4% was arrived via private medical and dental clinic. 6. In respect of treatment, open reduction was 55.5% of all, closed reduction was 37.2%. In children, closed reduction was done in 50.6%.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.2
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• pp.308-319
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• 2003

Mechanical forces are known to have an effect on bone formation, maintenance and remodeling, and there is evidence that the development of the mandibular condyle in the rat or mouse is influenced by altered functional force. However, studies are lacking in molecular-biologic mechanism such as the identification of differentiation factor induced from functional force. Here a mouse model was used to investigate the functional stress-responsive gene or factors which is related to the altered force by comparing the expression genes of functional state and hypo-functional state of the mouse mandible. ICR mice were provisioned with either a soft, mushy diet (soft-diet group) or hard rat pellets (hard-diet group) beginning at weaning for the alteration of functional force and subsequently sacrificed at 89 days of age. Incisor of mice in group 1 were trimmed twice a week to reduce occlusal forces. After killing the animals, mandibular bone including condyle were collected for RNA extraction, subtractive hybridization, northern blot analysis and mRNA in-situ hybridization. The results as follows; 1. A total of 39 clones were sequenced, and 11 individual sequence types were subsequently identified by subtractive hybridization, as 28 clones were represented twice in the analyzed sets. 2. Consequently four candidate clones, FS-s (functional stress-specific)2, -5, -18, and -22 were identified and characterized by homolgy search and northern analysis. Four of these clones, FS-s2, -5, -18, and -22, were shown to be expressed differentially in the hard-diet group. 3. Histologic sections showed that osteoblastic activity along the bone trabeculae and active bone remodeling were significantly lower in soft than in hard diet animals. A soft diet seems to enable a longer period of endochondral ossification in the mandibular condyle. 4. Although the mRNAs of FS-s2, -5, -18, and -22 were expressed rarely by cells of the soft-diet group, highest expression was detected in the cells of the hard-diet group. Together with the above results, it is suggested that FS-s2, -5, -18, and -22 could act as an important factors controlling the tissue changes in response to functional stress. The exact functional significance of these findings remains to be established.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.3
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• pp.239-249
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• 2001

The purpose of this study is to evaluate the relationship of the factors which could be influenced by orthognathic surgery especillay SSRO. We measured the amounts of the maximum opening, lateral movements, maximum velocity and pattern of mandibular path during the opening and closing of mandible at the following times ; preoperative, 1 month after operation, 6 months after operation respectively using MKG. And the results were compared according to the categorized subgroups. Following results were obtained : 1. The change of the amounts of mandibular lateral movement and maximum opening velocity were statistically different between male and female (p<0.05), but the others were not. 2. According to the method of operation, there was no difference in the change of the mandibular movements between the group of SSRO and SSRO plus LeFort I osteotomy (p>0.05). 3. According to the amounts of mandibular movement, the recovery of left lateral movement of the group of $6{\sim}10mm$ was better than the other groups (p<0.05). 4. In the frontal pattern of the opening and closing of the mandible, the complex deflected type (F5), simple deflected type (F4), complex deviated type (F3), simple deviated type (F2), straight type (F1) were obtained in order at the time of preoperative, simple deflected type, simple deviated type, complex deviated type, straight type, complex deflected type in order at the time of 1 month after surgery, and the result at the time of 6 months after surgery was the same with that of the time of preoperative. In the sagittal pattern, non-coincident type (S2) was predominant at the time of preoperative, and coincident type (S1) was predominant at the time of 1 month after surgery. After 6 months, the result was also the same with that of the preoperative in sagittal pattern. 5. There was not a statistical difference in the change of the mandibular movement between group of presence of the preoperative TMJ symptoms and non-presence group (p>0.05). 6. There was not a statistical difference in the change of the mandibular movement between repositioning device applied group and non-applied group (p>0.05). 7. Sixty three percents of the patients who had preoperative TMJ symptoms were improved after surgery and preoperative TMJ symptoms were more improved after operation in the repositioning device non-applied group statistically (p<0.05).