• Journal of Periodontal and Implant Science
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• 제31권3호
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• pp.581-595
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• 2001

In performing implant procedures in the anterior portion of the maxilla, many difficulties exist because of anatomical reasons, such as the proximity of the nasal floor, lateral extension of the incisive canal, and labial concavity. On the other hand, in the posterior region of the maxilla, there is often insufficient recipient bone between the maxillary sinus and alveolar ridge due to alveolar ridge resorption and pneumatization of the maxillary sinus. In order to perform implants in such regions, ridge augmentation procedures such as onlay bone graft, guided bone regeneration, and maxillary sinus grafting are performed. In studies of Caucasians, use of autograft from mandibular symphysis has been reported to be highly successful in maxillary sinus grafting. However, in a clinical study of Koreans, autograft of mandibular symphysis has been reported to have significantly low success rate. It has been hypothesized that this is because of insufficient cancellous bone due to thick cortical bone. In order to test this hypothesis, bone quality and morphology of Koreans can be compared with those of Caucasians. In this study, the bone density and morphology of the cortical bone and cancellous bone in the mandibular symphysis of 35 Korean cadavers were evaluated. The following results were obtained: 1. In terms of bone density, type I, type II, and type III consisted of 1.4%(3/213), 72.3%(154/213), and 26.3%(56/213) of the cross-sectioned specimens, respectively. In general, the bone density tended to change from type II to type III, as cross-sectioned specimens were evaluated from the midline to the canine. Type IV wasn't observed in this study. 2. The distance between the root apex and the lower border of the cancellous bone was 18.34mm-20.59mm. Considering that the bone has to be cut 5mm below the root apex during the procedure, autografts with about 15mm of vertical thickness can be obtained. 3. The thickness of cortical bone on the labial side increased from the root apex to the lower border of the mandible. The average values ranged from 1.43mm to 2.36mm. 4. The labio-lingual thickness of cancellous bone ranged from 3.43mm to 6.51mm. The thickness tended to increase from the apex to the lower border of the mandible and decrease around the lower border of cancellous bone. From the above results, the anatomic factors of the mandibular symphysis (bone density, thickness, quantity and length of the cortical bone and cancellous bone) didn't show any difference from Caucasians, and it cannot be viewed as the cause of failure in autografts in the maxillary sinus for implants.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권3호
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• pp.204-210
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• 2007

This study was intended to compare the cranial base morphology between the mandibular prognathism and maxillary retrognathism in skeletal class III patients. The subject of the present study was composed of 88 patients divided into two groups; Group 1 (Skeletal Class III with mandibular prognathism. SNA within normal range, SNB over normal range, n=54) and Group 2(Skeletal Class III with maxillary retrognathism. SNA below normal range, SNB within normal range, n=34). Lateral cephalogram were taken immediate before surgery and 18 landmarks were used to analyze the characteristics of cranial base and maxillomandibular skeleton. The result revealed that cranial base angle is significantly smaller in Group 1 than Group 2, which implies the influence of the cranial base angulation on the mandibular position. However the posterior cranial base length did not influence the mandibular horizontal position and anterior cranial base length did not influence the maxillary horizontal position. As the anterior cranial base length was closely related with ramal height, it is recommendable to investigate the regulatory mechanism of chondrogenesis of cranial base and condyle cartilage in the future research.

• 대한치과의사협회지
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• 제22권1호통권176호
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• pp.9-19
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• 1984

• 대한구순구개열학회지
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• 제5권1호
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• pp.27-42
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• 2002

This study was designed to evaluate the morphology and the position of the mandible in the complete unilateral cleft lip and palate patients, Craniofacial skeletal morphology pattern was analyzed on the lateral cephalometric radiographs of the 50 subjects of complete unilateral cleft lip and palate, the 50 normal and 50 class III, Each group was divided into child and adult sub-groups, All the data were tested statistically. The results were as follows: I, In the comparison with the normal group, complete cleft group showed smaller angular, condylar length, clockwisely rotated mandible and larger NMe/SGo(p<0.01). 2, In the comparison with the class III group, the complete cleft group showed significantly smaller angular, condylar, ramal, body length of the mandible(p<0,01). 3. As for the position of the mandibular condyle to the cranial base, the class III group was the most anterior, the normal group was the most posterior and the complete cleft group was in the middle(p<0.05). 4. In the comparison with child group, the normal adult group showed smaller mandibular angle and mandibular plane angle, but not the other two groups. And the complete cleft group and the class III group showed the similar change. The normal and class III group showed increased XiCd/XiPog, but not the complete cleft group(p<0.01).

• 대한치과교정학회지
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• 제9권1호
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• pp.85-98
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• 1979

This investigation was designed to compare the craniofacial and dental morphology of class III malocclusion with that of normal occlusin in children, and to determine the incidence of various class III craniofacial skeletal patterns. The material selected for this study consisted in standard lateral cephalograms of eighty two Korean children, forty one boys and forty one girls, aged 10 through 12 years, having class III malocclusion, and forty two Korean children, twenty boys and twenty two girls, with normal occlusion in the same age. Using the tracings of the standard lateral cephalograms, various angular and linear measurements were recorded, tabulated and statistically analyzed, and then the class III craniofacial skeletal morphology was divided into various patterns by the degree of SNA and SNB, which respectively were below, within or beyond the normal range of those of normal occlusion. The following characteristics of the craniofacial and dental morphology of class III malocclusion were observed. 1. The cranial base length of class III malocclusion was smaller than that of normal occlusion, and the small saddle angle was a characteristic figure of class III malocclucion. 2. Maxillary length of class III malocclusion was smaller than that of normal occlusion, and point A was retropositioned relative to cranial base but not PNS in class III malocclusion. Maxillary base inclination was not significantly different between the two, but occlusal plane to palatal plane was small in class III malocciusion. 3. The mandibular body length shown no difference between the two, but the mandibular body positioned anteriorly relative to cranial base in class III malocclusion. Ramus height, gonial angle, and mandibular effective length were large in class III malocclusion. Mandibular plane angle and joint angle had no difference between the two, and occlusal plane to mandibular plane angle was large in class III malocclusion. 4. Maxillary incisor inclination was not significantly different between class III malocclusion and normal occlusion, but mandibular incisors positioned and inclined lingually and consequently interincisal angle was large in class III malocclusion. 5. Class III malocclusion was divided into six categories of craniofacial skeletal pattern. The most common class III pattern was found to be one in which the maxilla was within the normal range of prognathism while the mandible extended beyond this range. The pattern in which the maxilla was below the normal range of prognathism while the mandible was within this range was approximately one fifth of the class III sample.

• 대한치과교정학회지
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• 제21권1호
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• pp.185-195
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• 1991

This study was undertaken to grope the correlation of the maximal bite force and tooth-craniofacial structure. The maximal bite force of 76 adult male, aged 18-28 (mean aged: $23.4{\pm}2.2$) years, was estimated and cephalometric headplates were measured, tabulated and statistically analyzed. The results were as follows. 1. 59.61kg of bite force in first molar, 45.38kg in premolar and 17.10kg in central incisor were arranged. 2. The bite force was negatively correlated to genial angle, mandibular plane angle, the angle between occlusal plane and mandibular plane, the angle between palatal plane and mandibular plane, and positively correlated to posterior height of face, length of mandibular body, length of ramus, facial depth in craniofacial structure. 3. The group with strong bite force showed small genial angle, mandibular plane angle, the angle between occlusal plane and mandibular plane, the angle between palatal plane and mandibular plane, and long posterior height of face, length of mandibular body, length of ramus, facial depth. So they manifested the tendency to brachycephalic pattern, on the other hand, the group with weak bite force manifested the tendency to dolichocephalic pattern. 4. There is no correlationships between bite force and mesial inclination of premolar axis in this subject. 5. It is considered bite force have an effect upon craniofacial pattern, especially upon the lower face.

• Imaging Science in Dentistry
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• 제37권2호
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• pp.79-82
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• 2007

Purpose: The purpose of this study was to investigate whether panoramic radiographs were useful in predicting osteoporosis. Materials and Methods: 50 postmenoposal women between the age of 41.8 and 78.5 were classified as normal and osteoporosis groups according to the bone mineral density of lumbar vertebrae. Panoramic radiographs were taken. Age, body mass index, remaining mandibular teeth, mandibular cortical thickness and morphology, and fractal dimensions at periapical areas of mandibular first molars were evaluated to differentiate the two groups. Results: The age of osteoporotic group was statistically significantly higher than that of normal group (p<0.05), but not the body mass index or number of remaining mandibular teeth. The mean fractal dimension of osteoporotic group was $1.391{\pm}0.085$, and was significantly lower than that of the normal group, which was $1.523{\pm}0.725$ (p<0.01). Thick mandibular cortical thickness was common in normal group, whereas thin or very thin mandibular cortical thickness was common in osteoporotic group and the difference was significant (p < 0.05). C2 pattern was common in normal group followed by C1, whereas C2 was common in osteoporotic group followed by C3. The difference was statistically significant (p< 0.0 1). Conclusion: Age, mandibular cortical thickness and shape, fractal dimension on panoramic radiographs were useful in predicting osteoporosis.

• Journal of Oral Medicine and Pain
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• 제48권1호
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• pp.16-24
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• 2023

Purpose: To determine the effects of botulinum toxin (BoNT) injection into the human masseter muscle on the morphology of the mandibular condyle bone using cone-beam computed tomography (CBCT). Methods: Twenty volunteers were randomly assigned to one of two groups. Group I received a single BoNT injection; Group II received two injections, with the second being administered 4 months after the first. CBCT scans of both temporomandibular joints (TMJs) were performed before and 6 months after the first injection. Bony changes in the cortical layers of the condyle heads were evaluated and the long and short axes of both mandibular condyles were measured. The thickness at the thinnest part of glenoid fossa was also quantitatively measured. Results: There was no significant difference between pre- and post-injection CBCT images. Furthermore, no changes in the cortical layers of the condyle heads were observed among the subjects who exhibited mild degenerative TMJ changes. The quantitative measurements (long axis, short axis, and the thickness of thinnest part of glenoid fossa roof) did not differ significantly between pre- and post-injection except for the long axis in Group I. Conclusions: Within the limitations of this study, it appears that BoNT injections into human masseter muscles do not alter the morphology of the mandibular condyle bone in healthy adults.

• Journal of Yeungnam Medical Science
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• 제38권1호
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• pp.47-52
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• 2021

Background: Short stature is defined as a height below the 3rd percentile or more than two standard deviations below the mean for a given age, sex, and population. There have been inconsistent results regarding craniofacial morphology in short-statured children. This study aimed to analyze the differences between short-statured children with growth hormone deficiency, idiopathic short-statured children, and normal children. Methods: Thirty-one short-statured children with growth hormone deficiency, 32 idiopathic short-statured children, and 32 healthy children were enrolled in this study. The measurements of their craniofacial structures from lateral cephalograms were evaluated. Results: There were statistically significant differences among the three groups seven variables (anterior cranial base length, posterior cranial base length, total cranial base length, upper posterior facial height, posterior total facial height, mandibular ramus length, and overall mandibular length) in the linear measurement and five variables (saddle angle, gonial angle, mandibular plane angle, position of mandible, and maxilla versus mandible) in the angular measurement. Conclusion: Compared to the control group, many linear and angular measurements of the craniofacial structures were significantly different in the two short-statured groups (p <0.05). Treatment plans by orthodontists should include these craniofacial structure characteristics.

• Restorative Dentistry and Endodontics
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• 제41권1호
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• pp.68-73
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• 2016

This case report describes a unique C-shaped mandibular second premolar with four canals and three apical foramina and its endodontic management with the aid of cone-beam computer tomography (CBCT). C-shaped root canal morphology with four canals was identified under a dental operating microscope. A CBCT scan was taken to evaluate the aberrant root canal anatomy and devise a better instrumentation strategy based on the anatomy. All canals were instrumented to have a 0.05 taper using 1.0 mm step-back filing with appropriate apical sizes determined from the CBCT scan images and filled using a warm vertical compaction technique. A C-shaped mandibular second premolar with multiple canals is an anatomically rare case for clinicians, yet its endodontic treatment may require a careful instrumentation strategy due to the difficulty in disinfecting the canals in the thin root area without compromising the root structure.