• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.1
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• pp.41-47
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• 1999

The route of bony invasion and spread pattern of tumor in the mandible are important in management of gingival cancer. Ten patients with gingival cancer involving mandibular body region were operated by composite resection. The radiographic and histopathologic features of the mandibular invasion and spread were analysed and compared. Our results showed that histopathologic extent of tumor invasion were greater than the radiographic prediction, especially in width of the tumor. And the pattern of bony invasion in the body area was mostly found in transmedullary spread rather than perineural spread. The vertical involvement in the mandibular body with tumor was evaluated. It indicated that if a oncologic surgeon was to ensure an adequate safety margin for extirpation of tumor, in most cases, the maintenance of the mandibular continuity is difficult. If the mandibular involvement by gingival cancer was identified radiographically and clinically, segmental mandibulectomy was required for the adequate safety margin, in consideration of the spread pattern in the body area.

• Imaging Science in Dentistry
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• v.51 no.2
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• pp.155-165
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• 2021

Purpose: This study aimed to evaluate changes of the alveolar bone and interdental bone septum of the mandibular incisors through cone-beam computed tomography (CBCT) after orthodontic treatment of mandibular dental crowding without dental extraction. Materials and Methods: The sample consisted of 64 CBCT images(32 pre-treatment and 32 post-treatment) from 32 adult patients with class I malocclusion and an average age of 23.0±3.9 years. The width and height of the alveolar bone and interdental septum, the distance between the cementoenamel junction (CEJ) and the facial and lingual bone crests, and the inclination of the mandibular incisors were measured. Results: The distance between the CEJ and the marginal bone crest on the facial side increased significantly (P<0.05). An increased distance between the CEJ and the bone crest on the facial and lingual sides showed a correlation with the irregularity index (P<0.05); however, no significant association was observed with increasing mandibular incisor inclination (P>0.05). The change in the distance between the CEJ and the marginal bone crest on the facial side was correlated significantly with bone septum height(P<0.05). Conclusion: Bone dehiscence developed during the treatment of crowding without extraction only on the incisors' facial side. Increasing proclination of the mandibular incisor was not correlated with bone dehiscence. The degree of dental crowding assessed through the irregularity index was associated with the risk of developing bone dehiscence. The interdental septum reflected facial marginal bone loss in the mandibular incisors.

• Journal of dental hygiene science
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• v.13 no.2
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• pp.197-202
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• 2013

The purpose of this study was to examine the relationship between the physique of 147 dental hygiene students and the size of their dental arch. A survey was conducted, and impression taking was carried out at the same time to measure the arch length and width of the students. The findings of the study were as follows: 1. 74.8 percent of the students got a dental checkup over the past year. 86.4 percent breathed through the nose. 18.4 percent had ever received orthodontic treatment, and 49.7 percent had ever had their tooth extracted. 94.6 percent were fond of refined food, and 52.4 percent had a liking for hard food. 2. There were no statistically significant differences in arch length and width according to all the variables that related the size of dental arch. 3. Out of the physique variables, weight was identified as a variable to make a statistically significant difference to arch length and width. A heavier weight led to larger mandibular inter-canine width and larger maxillary inter-molar width. 4, A heavier weight had a weaker positive correlation to inter-canine width and inter-molar width. Arch length and width were most closely linked to maxillary inter-molar width and mandibular inter-molar width. The above-mentioned findings show that weight exerted an influence on the form of dental arch among the physique variables. In the future, sustained research efforts should be made to keep track of the relationship between the change of physique and the change of dental arch to improve the stability of occlusion and promote oral health.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.4
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• pp.678-685
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• 2006

A certain width of attached gingiva is required to maintain gingival health The purpose of this study was to examine the dimensional changes in the width of attached gingiva and the depth of gingival sulcus among the deciduous, mixed and permanent dentitions and establish baseline information on the width of attached gingiva in Korean children. Eighty-eight children aged 4 to 14, who visited the Department of Pediatric Dentistry at Samsung Medical Center, were selected and divided into 3 groups according to the periods of dentition: deciduous, mixed and permanent dentitions. The width of keratinized gingiva and the depth of gingival sulcus were measured in each group with a periodontal probe and the width of attached gingiva was determined. The width of attached gingiva in maxillary and mandibular first molars increased significantly with age after eruption in the permanent dentition (p<0.05). The sulcus depth significantly increased in newly erupted permanent teeth with narrower width of attached gingiva (p<0.05) in all of the experimented teeth with the exception of the mandibular central incisor during the transition period. The results suggest that the mean width of attached gingiva does not increase steadily from the deciduous to the permanent dentition.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.4 no.1
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• pp.11-20
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• 1974

The author conducted an experiment using P-A Cephalography of 242 male and female subjects of ages ranging 2-6, 7-15, and adult group. By means of Nakago's method of measurement, the standard value of Korean was obtained. The results were as follows; 1. In the group of an age, the male value was greater slightly than female value. 2. In each age group the difference between the right and left widths could be recognizable, however, it was not much great. 3. In each group, regardless of sex, the growth relation was clearly distinguishable at PO, ARI, ARE, MG, AG, and CAW. 4. When the standard value of adult Korean was compared with that of Japanese, Japanese was great with respect to the width of maxillary portion and Korean was great with respect to the width of mandibular portion. 5. Maximum head width of white man was almost similar to that of Korean, however, maxillary alveolar base width of white man was considerably small or the dental arch was narrow.

• The korean journal of orthodontics
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• v.47 no.4
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• pp.222-228
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• 2017

Objective: To evaluate soft- and hard-tissue changes in the mandibular angle area after the administration of botulinum toxin type A (BoNT-A) injection to patients with masseteric hypertrophy by using three-dimensional cone-beam computed tomography (3D-CBCT). Methods: Twenty volunteers were randomly divided into two groups of 10 patients. Patients in group I received a single BoNT-A injection in both masseter muscles, while those in group II received two BoNT-A injections in each masseter muscle, with the second injection being administered 4 months after the first one. In both groups, 3D-CBCT was performed before the first injection and 6 months after the first injection. Results: Masseter muscle thicknesses and cross-sectional areas were significantly reduced in both groups, but the reductions were significantly more substantial in group II than in group I. The intergonial width of the mandibular angle area did not change significantly in either group. However, the bone volume of the mandibular gonial angle area was more significantly reduced in group II than in group I. Conclusions: The repeated administration of BoNT-A injections may induce bone volume changes in the mandibular angle area.

• The korean journal of orthodontics
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• v.29 no.3 s.74
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• pp.303-315
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• 1999

The aim of this study was to evaluate the morphology of the mandibular symphysis and anterior alveolar and skeletal relationship under the influence of the rotational growth pattern of mandible in skeletal Class III malocclusion. A total of U untreated adult subjects were divided into two groups-forward rotational growth pattern group, backward rotational growth pattern group-according to the suggestion of Skieller et al.. The antero-posterior position, vertical relationship, mandibular symphysis and anterior alveolar and skeletal relationship were assessed on lateral cephalometric radiographs. Mandibular symphysis and anterior alveolar and skeletal relationship in each subject were studied and the following conclusions were drawn : 1. Concerning the antero-posterior position, forward rotational growth pattern group showed significantly larger SNA, SNB. Conceming the vertical relationship, all measurements showed statistically significant differences. 2. Forward rotatioal growth pattern group showed significantly larger IMPA, MnAD, backward rotational growth pattern group showed significantly larger MxABH. 3. There was no statistically significant difference in symphysis ratio to mandibular plane between forward and backward rotational growth pattern group. 4. In the correlative analysis of rotational growth pattern of mandible and mandibular symphysis, anterior alveolar and skeletal relationship, statistically significant correlations in overbite, IMPA, MnAD, symphysis width were showed.

• Imaging Science in Dentistry
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• v.33 no.3
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• pp.187-193
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• 2003

Purpose: To compare the measurements of the mandible and the detectability of the mandibular canal on reformatted images using a newly developed 3-dimensional implant simulation program with traditionally used CT multiplanar reconstruction program and true measurements. Materials and Methods: Ten dry dog mandibles were used in this study. Occlusal templates for CT examination were fabricated and marked with gutta perch a at ten sites. Axial CT scans were taken and reconstructed using DentaScan (D group) and Vimplant program (V group), and each mandible was sectioned at the previously marked sites (R group). Maximum vertical height (H) and maximum width (W) of the mandible, the distances from buccal border of the mandibular canal to the most buccal aspect of the mandible (X), and the distance from the superior border of the mandibular canal to the alveolar crest (Y) were measured, and the mandibular measurements in each group were compared. Detectability of mandibular canal was evaluated using a 3-point scale in both V and D groups by three oral radiologists and compared. Results: H in the V group was slightly greater than that in the D group, and Wand X in the V group was slightly less than those in the D group. H in the V group was less than that in the R group, and Wand X in the V group was larger than those in the R group. The detectability of the mandibular canal did not show statistically significant differences between V and D groups. Conclusion: The results of the experiment show that the newly developed, inexpensive Vimplant/TM/ simulation program can be used as an alternative to the traditionally used, and more expensive CT multiplanar reconstruction program.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.27 no.2
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• pp.97-104
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• 2018

Mandibular anterior region has high implant survival rates and better accessibility compared with any other region. Even if there are possibilities for perforation on lingual cortical bone due to improper drilling and bleeding caused by lingual artery damage, mandibular anterior region is a safe region because less amount of major anatomical structures exist compared with other regions. However, because of narrow bucco-lingual width of alveolar ridge, it is challengeable to obtain esthetic implant prosthesis. Although patients are less sensitive subjectively, mandibular anterior region is as difficult as maxillary anterior region in that implant placement location plays a critical role on the prognosis of implant prosthesis. One-piece implant is a very useful option for mandibular anterior region. Considering the narrow roots and thin alveolar bone of mandible, it is clinically difficult for implant diameter to be greater than 3mm In this case, we could approach the esthetic restoration in mandibular anterior region with one-piece implant and immediate loading.

• The korean journal of orthodontics
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• v.33 no.2 s.97
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• pp.85-90
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• 2003

The symphyseal mandibular fractures due to accidents happened in form of collapsed transeverse arch and multiple teeth loss. And the collapsed transverse arch in mandible occurs with unilaterally or bilaterally. So that patient needs to recover arch width. Conventional approaches, however, we difficult to get appropriate transverse arch correction. Distraction osteogenesis is a unique form of clinical tissue engineering and biologic process of new bone formation between bone segments that are gradually separately by incremental traction. Distraction osteogenesis is considered that great potential for correcting transverse mandibular deficiencies. Tn this paper, distraction osteogenesis applied to patients who had a unilateral or bilateral collapsed arch width in mandible. But it was necessary secrutinize consideration about periodontal conditions, biomechanical vectors, TMJ adaptations, and neuromuscular change during distraction osteogenesis period.