• The korean journal of orthodontics
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• v.29 no.2 s.73
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• pp.209-217
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• 1999

This study was concerned with comparing the measured values of labial alveolar bone through the lateral cephalometric radiography and mandibular incisor cross-sectional tomogram between two groups, one group of mandibular prognathism patients who needed an orthognathic surgery as an experimental group and the other group who had normal molar relationships as a control group. The purpose of the study was to find out the predisposing factor of bone resorption and gingival recession before orthodontic treatment. The results were as follows: 1. The cross-sectional area of labial alveolar bony plate in mandibular prognathism was significantly smaller than that of control group. 2. In mandibular prognathism, the distance between cementoenamel junction and alveolar crest was significantly greater than control group. 3. There were negative correlations between area of labial alveolar bony plate and distance from cementoenamel junction to alveolar crest, and positive correlations between area of labial alveolar bony plate and distance from alveolar crest to root apex. 4. In mandibular prognathism, there were positive correlations between IMPA and thickness of symphysis, and negative correlations between IMPA and the alveolar bony height. The results of the present study suggest the mandibular prognathism patients are prone to the gingival recession due to the small amount of labial alveolar bone around lower incisors.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.4
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• pp.338-345
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• 1993

Mandibular discontinuity defect due to benign tumor, malignant tumor, infection, or truma results in major esthetic and biologic compromise. The primary goal of reconstruction is full restitution of function, which secondarily lead to normalization of the cosmetic deformity. The authors make a clinical study of 61 consecutive bone graft cases for mandibular reconstruction of discontinuity defect which were studied retrospectively using clinical data and radiographic findings. The cases were reviewed to evaluate the clinical success in the period from 1981 to 1990 in the Dept. of Oral & maxillofacial Surgery, Seoul National University Hospital. The criteria of the success in bone graft, are no residual infection, graft in with maintain its integrity, and remain over a half of its original size of graft in the radiographic features. The purpose of this clinical survey is to study of the mandibular discontinuity defects and success rate of free bone graft in mandibular defects. To summarize the clinical study of free bone graft, the main type of autogenous bone graft is iliac bone and corticocancellous type. Overall success rate is 80.3% in 61 followup cases over 6 months. Wire fixation and Extraoral approach has realtively better prognosis than other methods. It showed relatively poor prognosis in symphysis defects than other recipient site.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.23 no.1
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• pp.27-44
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• 1993

This study was performed to investigate the changes of mandibular condyle by low calcium diet and the effects of irradiation on the bone in osteoporotic state. In order to carry out this experiment, 80 seven-week old Sprague-Dawley strain rats weighing about 150 gm were selected and equally divided into one experimental group of 40 rats and one control group with the remainder. The experimental group and the control group were then subdivided into two group and exposed to irradiation. The two irradiation groups received a single dose of 20 Gy on the jaw area only and irradiated with a cobalt-60 teletherapy unit. The rats in the control and experimental groups were serially terminated by fours on the 3rd, the 7th, the 14th, and the 21st day after irradiation. After termination, both sides of the dead rats mandibular condyle were removed and fixed with 10% neutral formalin. The bone mineral density of mandibular condyle was measured by use of dual energy X-ray bone densitometer(model DDX-alpha, Lunn Corp., U. S. A.). The mandibular condyle was radiographed with Hitex HA-80(Hitex Co., Japan). Thereafter, the obtained radiographs were observed, and the mandibular condyle was further decalcified and embedded in paraffin as the general method. The specimen sectioned and stained with hematoxylin-eosin, PAS and Rabbit Anti-Human Tumor Necrosis Factor-a observed by a light microscope. The obtained results were as follows: 1. In the non-irradiated group with the low calcium diet, the bone mineral density of the condyle was markedly decreased after 14 days, and decrease the number of trabeculae of the condyle and resorption of the calcified cartilaginous zone were observed after 3 days. On microscopic observations, the number nd size of trabeculae were decreased after 7 days of experiment. 2. In the irradiated group with the low calcium diet, the bone mineral density of the condyle was markedly decreased after 14 days and resorption of the calcified cartilaginous zone and decrease the number and coarse of the trabeculae of the condyle were observed. These findings were extended rather than in non-irradiated group with low calcium diet. On microscopic observations, many osteoclasts were detected and the number and size of trabeculae were somewhat decreased after 7 days. Also there was degenerative changes of tissues of bone marrow on the 14th day but that condition was restored on the 21st day of experiment. 3. In the irradiated group with normal diet, the bone mineral density of the condyle was somewhat decreased with times and degree of decrease of the number of trabeculae was somewhat larger than in the non-irradiated group with normal diet. On microscopic observations, the tissues of bone marrow were atrophic and degenerative changes but that condition was restored on the 21st day of experiment. 4. In immunocytochemical findings, in the irradiated and non-irradiated groups with low calcium diet, negative or partial positive response to TNF was observed, but positive response in the normal diet groups.

• Imaging Science in Dentistry
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• v.53 no.4
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• pp.383-388
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• 2023

Simple bone cyst is a pseudocyst that typically occurs in patients during their second and third decades of life. This benign entity is an empty or fluid-filled cavity that lacks a true epithelial lining. Simple bone cysts are often asymptomatic and are commonly found in mandibular body, predominantly in the posterior region. The treatment of simple bone cysts can be influenced by factors such as the patient's age, the size of the lesion, and the presence or absence of symptoms. In the case of a simple bone cyst in the mandible that is small and symptomless, a watchful waiting approach may be appropriate. However, if the cyst is large and symptomatic, surgical treatment is recommended. This report presents a radiological examination of a simple bone cyst that developed around the root of the mandibular first molar in a 36-year-old female patient. The cyst recurred in adjacent areas despite surgical treatment.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.40
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• pp.5.1-5.8
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• 2018

Background: The objective of this study was to evaluate the influence of masticatory muscle injection of botulinum toxin type A (BTX-A) on the growth of the mandibular bone in vivo. Methods: Eleven Sprague-Dawley rats were used, and BTX-A (n = 6) or saline (n = 5) was injected at 13 days of age. All injections were given to the right masseter muscle, and the BTX-A dose was 0.5 units. All of the rats were euthanized at 60 days of age. The skulls of the rats were separated and fixed with 10% formalin for micro-computed tomography (micro-CT) analysis. Results: The anthropometric analysis found that the ramus heights and bigonial widths of the BTX-A-injected group were significantly smaller than those of the saline-injected group (P < 0.05), and the mandibular plane angle of the BTX-A-injected group was significantly greater than in the saline-injected group (P < 0.001). In the BTX-A-injected group, the ramus heights II and III and the mandibular plane angles I and II showed significant differences between the injected and non-injected sides (P < 0.05). The BTX-A-injected side of the mandible in the masseter group showed significantly lower mandibular bone growth compared with the non-injected side. Conclusion: BTX-A injection into the masseter muscle influences mandibular bone growth.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.5
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• pp.276-284
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• 2019

Objectives: This study sought to compare efficiency results between the use of a customized implant (CI) and a reconstruction plate (RP) in mandibular defect reconstruction in an animal model. Materials and Methods: Fifteen rabbits underwent surgery to create a defect in the right side of the mandible and were randomly divided into two groups. For reconstruction of the mandibular defect, the RP group (n=5) received five-hole mini-plates without bone grafting and the CI group (n=10) received fabricated CIs based on the cone-beam computed tomography (CBCT) data taken preoperatively. The CI group was further divided into two subgroups depending on the time of CBCT performance preoperatively, as follows: a six-week CI (6WCI) group (n=5) and a one-week CI (1WCI) group (n=5). Daily food intake amount (DFIA) was measured to assess the recovery rate. Radiographic images were acquired to evaluate screw quantity. CBCT and histological examination were performed in the CI subgroup after sacrifice. Results: The 1WCI group showed the highest value in peak average recovery rate and the fastest average recovery rate. In terms of reaching a 50% recovery rate, the 1WCI group required the least number of days as compared with the other groups ($2.6{\pm}1.3days$), while the RP group required the least number of days to reach an 80% recovery rate ($7.8{\pm}2.2days$). The 1WCI group showed the highest percentage of intact screws (94.3%). New bone formation was observed in the CI group during histological examination. Conclusion: Rabbits with mandibular defects treated with CI showed higher and faster recovery rates and more favorable screw status as compared with those treated with a five-hole mini-plate without bone graft.

• Journal of Veterinary Clinics
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• v.37 no.6
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• pp.363-366
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• 2020

A 2-month-old, 50 kg male Korean native calf was referred with bilateral mandibular fractures. The bilateral mandible was hanging loose, with inability to use the jaw, indicated by excessive salivation. Radiography revealed a long oblique fracture in the right mandible, and a short oblique fracture in the left mandible. Computerized Tomography, a different form of radiography, revealed the fracture in the left mandible to be a comminuted fracture. In order to stabilize the bilateral mandible fractures, a combination of bone plate and wiring was applied; in addition, resin was applied to enhance stabilization of the mandible. Six weeks after surgery, the calf was able to masticate and ruminate well. In this case, application of the plate and wiring with resin to bilateral mandibular fractures presented a successful functional recovery. Accordingly, the combination of bone plate and wiring with resin can be an effective technique for treating mandibular fractures.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.6
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• pp.474-480
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• 2009

These is a cases of chronic suppurative osteomyelitis occurred in the mandibular body to condyle of 48-year-old male patient. Extensive bone destruction was noted on the right mandibular body, angle, ascending ramus, mandibular notch and condylar region. We made a treatment plan that radicular mandibular resection from body to condyle and mandibular reconstruction with vascularized fibular flap at first time. But, we could observe marked bone regeneration with only mild curettage, local wound care and massive antibiotic therapy. So we preserved the anterior ramus portion of mandible. Defected mandibular condyle was reconstructed with costochondral graft. In this paper we present the case of a patient who has chronic osteomyelitis in mandibular area.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.1
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• pp.1-9
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• 2007

Purpose: To evaluate the effect of compression on the distracted area in new bone formation during mandibular distraction osteogenesis in rabbits. Materials and method: Sixteen rabbits, weighing approximately 2 Kg, and the prefabricated distraction device were used. With the rabbits under general anesthesia, we performed vertical osteotomies between the anterior and posterior mandibular teeth and then placed the distraction device. After a 5 -day latency period, the mandible was distracted to a length of 10.0 mm at a rate of 1 mm/day and then immediately compressed 4 mm in the experimental group (n=8). In the control group (n=8), the mandible was distracted to a length of 6.0 mm at a rate of 1 mm/day. Rabbits in the control group were killed at 2 and 8 weeks during the consolidation period. The specimens were evaluated with light microscope after H & E stain. Histomorphometric analysis was done at 8 week specimens. Results: All experimental animals showed mandibular elongation on the macroscopical and radiographic evaluations. At 2 week, immature bone formation was observed from the surface of the host bone margins with collagen fibers arranged parallel to the direction of distraction in the control group; in the experimental group, immature bone formation was observed adjacent to the host bone, and the collagen fibers were not arranged uniformly. At 8 week, spindle-shaped new bone formation was seen in the direction of distraction in distracted area of the control group, while in the experimental group, the newly formed bone was arranged in a multidirectional manner, like the pattern of trabeculae. In the histomorphometric analysis of 8 weeks, the area of bone deposition was $2.12{\pm}\;0.75\;inch^2$ in the experimental group and $0.87{\pm}0.51\;inch^2$ in the control group (p<0.01). The bone deposition ratio was $29.60{\pm}10.50%$ in the experimental group and $12.10{\pm}7.17%$ in the control group (p<0.01). Conclusion: These results suggest that compression after over-distraction during the mandibular distraction osteogenesis is an effective method of increasing the amount of newly formed bone in distracted area.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.5
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• pp.232-239
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• 2015

Objectives: The purpose of this study was to estimate the volumetric change of augmented autobone harvested from mandibular body cortical bone, using cone-beam computed tomography (CBCT) and three-dimensional reconstruction. In addition, the clinical success of dental implants placed 4 to 6 months after bone grafting was also evaluated. Materials and Methods: Ninety-five patients (48 men and 47 women) aged 19 to 72 years were included in this study. A total of 128 graft sites were evaluated. The graft sites were divided into three parts: anterior and both posterior regions of one jaw. All patients included in the study were scheduled for an onlay graft and implantation using a two-stage procedure. The dental implants were inserted 4 to 6 months after the bone graft. Volumetric stability was evaluated by serial CBCT images. Results: No major complications were observed for the donor sites. A total of 128 block bones were used to augment severely resorbed alveolar bone. Only 1 of the 128 bone grafts was resorbed by more than half, and that was due to infection. In total, the average amount of residual grafted bone after resorption at the recipient sites was $74.6%{\pm}8.4%$. Conclusion: Volumetric stability of mandibular body autogenous block grafts is predictable. The procedure is satisfactory for patients who want dental implants regardless of atrophic alveolar bone.