• Maxillofacial Plastic and Reconstructive Surgery
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• 제39권
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• pp.21.1-21.6
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• 2017

Background: The purposes of the present study were to compare implant stabilities of mandibular block bone graft and bovine bone graft and to evaluate influencing factors for implant stability in mandibular block bone (MBB) graft. Methods: This retrospective study investigated 1224 cases and 389 patients treated by one surgeon in the Department of Oral and Maxillofacial Surgery of Pusan National University Dental Hospital (Yangsan, Korea) between January 2010 and December 2014. Proportions that MBB graft cases constitute in all implant restoration cases and in all bone graft cases were measured. Implant stability quotient (ISQ) values were achieved by the same surgeon before loading. The average ISQ values of the experimental groups were compared. In addition, ISQ values of influencing factors, such as age, sex, implant size, and implant placement site, were compared within the MBB group using $Osstell^{TM}$ Mentor ($Osstell^{(R)}$, $G{\ddot{o}}teborg$, Sweden). Paired t test and ANOVA were conducted for statistical analysis with a significance level of 0.05. Results: Fifty-five percent of all implant restoration cases performed bone graft while MBB cases constituted 34% of all implant restoration cases and 61% of all bone graft cases. Comparing ISQ values according to bone graft materials, the MBB group manifested sufficient implant stability by presenting comparable ISQ value to that of the experimental group without bone graft. Among the reviewed factors, females, mandibular molar regions, and implants in larger diameter displayed greater implant stabilities. Conclusions: Satisfactory implant stability was accomplished upon administration of MBB graft. Within the limitation of this study, gender, implant site, and implant diameter were speculated to influence on implant stability in MBB graft.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제31권4호
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• pp.294-305
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• 2009

Purpose: This retrospective study evaluated the changes in hyoid bone and tongue positions as well as oral cavity volume after mandibular setback by BSSRO. Materials and Methods: 18 Koreans who underwent BSSRO to correct mandibular prognathism were studied. Lateral cephalograms were taken and traced preoperatively (T0), immediately (T1) and approximately 6 months postoperatively (T2). Submentovertex radiograghs were taken and traced before surgery (T0) and about 6 months after surgery (T2). The area and volume of oral cavity, the vertical and horizontal dimensions of the hyoid bone and tongue dorsum were measured. Results: Mandibular setback surgery resulted in a significant reduction of lower oral cavity volume. The hyoid bone displaced posteroinferiorly immediately after surgery, and it tended to return to its original vertical position at 6 month after mandibular setback by BSSRO. The retropalatal space around tongue was maintained and the retrolingual space around tongue was reduced immediately postoperatively. The readaptation of tongue was not evident for that the follow up period was not long enough. No significant statistical correlations between the amounts of mandibular setback and the changes of oral cavity volume were observed. Conclusion: Mandibular setback surgery resulted in a significant reduction of lower oral cavity volume, which was most likely attributable to the posterior movement of the mandible. More subjects and long-term observations should be performed to assess the changes of oropharyngeal configuration following mandibular setback surgery.

• 대한치과교정학회지
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• 제37권3호
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• pp.220-230
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• 2007

골격성 I급이면서 수직적으로 정상인 환자 160명(남자 80명, 여자 80명)의 측모 두부방사선 계측사진을 대상으로 하악 전치부 치조골의 협설측 두께를 치축을 기준으로 계측하여 연령에 따른 차이를 조사하여 다음과 같은 결과를 얻었다. 하악전치부 치조골의 협설측 두께와 하악 전치부 설측 치조골의 두께는 연령이 증가함에 따라 여자의 CEJ 하방 2 mm 부위를 제외하고는 남녀 모두에서 유의한 감소를 보였다. 반면에, 하악 전치부 협측 치조골의 두께와 하악 이부 최대 풍융부의 두께는 연령이 증가함에 따라 유의한 차이를 보이지 않았다. 이상의 연구를 통하여 한국인에 있어서 수평적으로 I급의 골격형태이면서 수직적으로 정상인 환자에서는 성인보다는 성장기환자에서 하악 전치의 설측 치조골의 두께가 더 두꺼워 발치치료에서와 같은 하악 전치의 설측이동이 유리할 것으로 사료된다.

• Imaging Science in Dentistry
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• 제49권4호
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• pp.281-286
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• 2019

Purpose: The purpose of this study was to evaluate the morphology of the mandibular cortex in cases of medication-related osteonecrosis of the jaw (MRONJ) in patients with osteoporosis or bone metastases using a computer programme. Materials and Methods: Fifty-four patients with MRONJ (35 with osteoporosis and 19 with bone metastases) were examined using panoramic radiography. The morphology of the mandibular cortex was evaluated using a computer programme that scanned the mandibular inferior cortex and automatically assessed the mandibular cortical index (MCI) according to the thickness and roughness of the mandibular cortex, as follows: normal (class 1), mildly to moderately eroded (class 2), or severely eroded (class 3). The MCI classifications of MRONJ patients with osteoporosis or bone metastases were evaluated with the Pearson chi-square test. In these analyses, a 5% significance level was used. Results: The MCI of MRONJ patients with osteoporosis(class 1: 6, class 2: 15, class 3: 14) tended to be higher than that of patients with bone metastases(class 1: 14, class 2: 5, class 3: 0)(P=0.000). Conclusion: The use of a computer programme to assess mandibular cortex morphology may be an effective technique for the objective and quantitative evaluation of the MCI in MRONJ patients with osteoporosis or bone metastases.

• Imaging Science in Dentistry
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• 제40권2호
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• pp.83-87
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• 2010

Purpose : This study was to determine the relationship between age and the mandibular cortical bone thickness on panoramic radiograph. Materials and Methods : Panoramic radiographs of 360 patients (180 men and 180 women) over 20 years old, who visited the Chonbuk National University Hospital from January to December in 2007, were assessed. The subjects were divided into 5 age groups. Five indices such as cortical bone thickness at the gonion (GI), antegonion (AI), and below the mental foramen (MI), the panoramic mandibular index (PMI), the mandibular cortical index (MCI) were measured on panoramic radiographs. Results : All five indices including GI, AI, MI, PMI, and MCI showed significant differences between third decade and over 8 decade groups (p<0.05). PMI, MI and GI showed significant differences with gender statistically (p<0.05). Conclusion : The mandibular cortical bone thickness showed negative correlation with age, and the value of the thickness (PMI, MI, and GI) was greater in men than in women.

• 대한치과교정학회지
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• 제6권1호
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• pp.17-24
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• 1976

The primary objective of this study was to define the differences that exist. between different sexes on the dentoskeletal framework and the soft tissue profile around the mouth. For the purpose of this study, cephalometric radiographs were obtained from the centric occlusion with closed lip position, through the research on each 42 males and females aged from 17 to 22 years with normal occlusion and acceptable facial appearence. The results were as follows: 1. Maxillary to mandibular relationships. Among the angles formed by the long axis of the maxillary and mandibular anterior teeth, the maxillary and mandibular anterior alveolar bone, and the lower and upper lips (Fig.2), only the angle formed by the lips was more acute in males than in females. The males have a more rounded profile, and the females have a flatter profile in the lower third of the face. The differences is statistically significant for the angle formed by the lips. The fact that the lips have a difference greater than that of teeth or the alveolar bone indicates that the lip position is not entirely due to tooth and bony support. Possibly the thickness of the lips has an influence. 2. Occlusal plane. The occlusal plane was related to the anterior tooth inclination, anterior alveolar bone profile, and the lip contour, both maxillary and mandibular (Fig.3). Only the angle related to lower lip was statistically significant. The females again had the more obtuse angle, indicating a flatter profile than that of the males. 3.Skeletal planes. The angles formed by the anterior maxillary lips, teeth, and alveolar bone with the Frankfort plane and the angles of the mandibular lips, teeth, and, alveolar bone and the mandibular plane were investigated (Fig.4). Results were similar to those from maxillary to mandibular relationships. The results were statistically significant for the upper lip and the lower lip, only. 4. Esthetics. The facial line and the mandibular plane were compared with the esthetic line. These angles were different for the different sexes, but only the latter was statistically significant. This difference may be due to the profile contour of the nose.

• Journal of Korean Dental Science
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• 제3권2호
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• pp.4-11
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• 2010

Purpose: This study aimed at examining the thickness of lateral cortical bone in the mandibular posterior body and the location of the inferior alveolar nerve canal as well as investigating the clinically viable bone grafting site(s) and proper thickness of the bone grafts. Subjects and Methods: The study enrolled a total of 49 patients who visited the Department of Oral and Maxillofacial Surgery at Kyung Hee University Dental Hospital to have their lower third molar extracted and received cone beam computed tomography (CBCT) examinations. Their CBCT data were used for the study. The thickness of lateral cortical bone and the location of inferior alveolar nerve canal were each measured from the buccal midpoint of the patients' lower first molar to the mandibular ramus area in the occlusal plane of the molar area. Results: Except in the external oblique ridge and alveolar ridge, all measured areas exhibited the greatest cortical bone thickness near the lower second molar area and the smallest cortical bone thickness in the retromolar area. The inferior alveolar nerve canal was found to be located in the innermost site near the lower second molar area compared to other areas. In addition, the greatest thickness of the trabecular bone was found between the inferior alveolar nerve canal and the lateral cortical bone. Conclusions: In actual clinical settings involving bone harvesting in the posterior mandibular body, clinicians are advised to avoid locating the osteotomy line in the retromolar area to help protect the inferior alveolar nerve canal from damage. Harvesting the bone near the lower second molar area is judged to be the proper way of securing cortical bone with the greatest thickness.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권4호
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• pp.356-364
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• 2006

Transverse mandibular deficiency has a many problem in growing patients. Therefore, Mandible symphysis widening is recommended. A new surgical technique has been developed to widen the mandible. The purpose of this study is to report the effect of mandibluar symphyseal distraction osteogenesis by use of bone-borne type distractor. The surgical procedure was accomplished under general anaesthesia with step-line osteotomy. Bone-borne type distractor was used to generally widen the mandible. The expansion achieved in the mandible was 8.31mm at the device, 6.32mm at the canines, 4.06mm at the first molars. The symphyseal distraction gaps were bridged by new bony regeneration. Mandibular symphseal distraction osteogenesis increased mandibular arch width, stabilized occlusion, and corrected dental crowding.

• 한국임상수의학회지
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• 제20권1호
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• pp.138-141
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• 2003

First case, a one-year-old female Shih Tzu weighing 3 kg with closed transverse fractures of bilateral mandibular body between 2nd and 3rd premolar teeth were treated surgically with bone plates and screws, and cranial luxation of temporomandibular joints were reduced to closed method. Second case, a 8.4 years old male Yorkshire terrier weighing 2.6 kg with closed transverse/oblique fractures of bilateral mandibular body between premolar and molar teeth were treated surgically with bone plates and screws. Radiographic examination revealed that the fractures in two cases fixed well and temporomandibular joint was stabilized. One month after operation, jaw activity was excellent and malocclusion wasn't observed.

• 대한치과교정학회지
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• 제44권1호
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• pp.36-43
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• 2014

Objective: The purpose of this study was to quantitatively evaluate the cortical bone densities of the maxillary and mandibular alveolar processes in adults with different vertical facial types using cone-beam computed tomography (CBCT) images. Methods: CBCT images (n = 142) of adult patients (20-45 years) were classified into hypodivergent, normodivergent, and hyperdivergent groups on the basis of linear and angular S-N/Go-Me measurements. The cortical bone densities (in Hounsfield units) at maxillary and mandibular interdental sites from the distal aspect of the canine to the mesial aspect of the second molar were measured on the images. Results: On the maxillary buccal side, female subjects in the hyperdivergent group showed significantly decreased bone density, while in the posterior region, male subjects in the hyperdivergent group displayed significantly decreased bone density when compared with corresponding subjects in the other groups (p<0.001). Furthermore, the subjects in the hyperdivergent group had significantly lower bone densities on the mandibular buccal side than hypodivergent subjects. The maxillary palatal bone density did not differ significantly among groups, but female subjects showed significantly denser palatal cortical bone. No significant difference in bone density was found between the palatal and buccal sides in the maxillary premolar region. Overall, the palatal cortical bone was denser anteriorly and buccal cortical bone was denser posteriorly. Conclusion: Adults with the hyperdivergent facial type tend to have less-dense buccal cortical bone in the maxillary and mandibular alveolar processes. Clinicians should be aware of the variability of cortical bone densities at mini-implant placement sites.