• 대한치과교정학회지
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• 제41권1호
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• pp.51-58
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• 2011

Objective: To evaluate the shear bond strength (SBS), fracture mode, wire pull out (WPO) resistance and microleakage between low-shrinking and conventional composites used as a lingual retainer adhesive. Methods: A total of 120 human mandibular incisor teeth, extracted for periodontal reasons, were collected. Sixty of them were separated into two groups. To determine the SBS, either Transbond-LR (3M-Unitek) or Silorane (3M-Espe) was applied to the lingual surface of the teeth by packing the material into standard cylindrical plastic matrices (Ultradent) to simulate the lingual retainer bonding area. To test WPO resistance, 20 samples were prepared for each composite where the wire was embedded in the composite materialand cured. Then tensile stress was applied until failure of the composite occurred. The remaining 60 teeth were divided into two groups and multi-stranded 0.0215-inch diameter wire was bonded with the same composites. Microleakage was evaluated by the dye penetration method. Statistical analyses were performed by Wilcoxon, Pearson chi-square, and Mann-Whitney-U tests at p < 0.05 level. Results: The SBS and WPO results were not statistically significant between the two groups. Significant differences were found between the groups in terms of fracture mode (p < 0.001). Greater percentages of the fractures showed mix type failure (85%) for Silorane and adhesive (60%) for Transbond-LR. Microleakage values were lower in low-shrinking composite than the control and this difference was found to be statistically significant (p < 0.001). Conclusions: Low-shrinking composite produced sufficient SBS, WPO and microleakage values on the etched enamel surfaces, when used as a lingual retainer composite.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권6호
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• pp.297-300
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• 2014

Objectives: To compare the clinical and radiological outcomes after closed reduction (CR) and open reduction and internal fixation (ORIF) in the management of subcondylar fractures. Materials and Methods: Forty-eight patients presenting with subcondylar fracture between January 2010 and March 2013 were evaluated retrospectively. Fifteen patients were treated with CR and 33 patients with ORIF. The clinical and radiologic parameters were evaluated during follow-up (mean, 7.06 months; range, 3 to 36 months). Results: In the CR group, no patients had any problems with regard to the clinical parameters. The average period of maxillomandibular fixation (MMF) was 5.47 days. The preoperative average tangential angulation of the fractured fragment was $3.67^{\circ}$, and loss of ramus height was 2.44 mm. In the ORIF group, no clinical problems were observed, and the average period of MMF was 6.33 days. The preoperative average tangential angulation of the subcondylar fragment was $8.66^{\circ}$, and loss of ramus height was 3.61 mm. Conclusion: CR provided satisfactory clinical results, though ORIF provided more accurate reduction of the fractured fragment. So there is no distinct displacement of fractured fragment, CR should be selected than ORIF because of no need for surgery.

• Journal of Periodontal and Implant Science
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• 제31권2호
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• pp.269-276
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• 2001

The purpose of this study was to evaluate the clinical validity of multi-rooted teeth subjected to root-resection treatment. Over a period of 1-7 years, 60 root-resected molars in 59 patients were examined clinically and radiographically. All patients were p0eriodically recalled once or twice a year. Root-resections were due to periodontal, more specifically furcal bone loss or marginal bone loss,in 34 cases and extensive dental carious destruction in 10 cases. In other cases,root-resections resulted from 6 cases of root fracture, 6 cases of periodontal-endodontic combined lesion, and 1 case of endodontic problem. Root-resection was carried out on 26 maxillary molars and 34 mandibular molars. The results are as follows; 1. 14 cases(23.3%) were considered failures. 8 cases(13.3%) of them occurred within the first year(8 cases, 13.3%), 4 cases(6.7%)between 1-3 years, and 2 cases(3.3%) between 4-7 years. 2. 8 cases(13.3%) were considered failures due to periodontal reasons, 3 cases(5%) due to root fracture, 2 cases(3.3%) due to endodontic problem, and 1 case(1.7%) due to prosthetic problem. 3. 37 cases(61.7%) showed up for the recall appointments, and the percentage of failures(13.5%) was lower compared with that of all patients(23.3%). The results of the present study indicate that the prognosis of root-resected teeth is favourable if attention is paid to the selection of proper case and to achieving optimal oral hygiene and periodic check up.

• Imaging Science in Dentistry
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• 제51권3호
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• pp.251-260
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• 2021

Purpose: Dental implants are widely used for the rehabilitation of edentulous sites. This study investigated the occurrence of dental implant malpositioning as shown on post-implantation cone-beam computed tomography (CBCT) and to identify related factors. Materials and Methods: Samples with at least 1 malpositioned dental implant were collected from a central radiology clinic in Tehran, Iran from January 2017 to January 2019. Variables such as demographic characteristics, length and diameter of implants, type of implant, sites of implant insertion, different types of implant malpositioning problems (cortical plate perforation, interference with anatomical structures), angulation of the implant, and the severity of malpositioning were assessed. In addition, the incidence of implant fracture and over-drilling was evaluated. Data were statistically analyzed using the chi-square test, 1-sample t-test, and Spearman correlation coefficients. Results: In total, 252 patients referred for implant postoperative CBCT evaluations were assessed. The cases of implant malpositioning included perforation of the buccal cortical plate (19.4%), perforation of the lingual cortical plate (14.3%), implant proximity to an adjacent implant (19.0%), implant proximity to an adjacent tooth (3.2%), interference with anatomical structures(maxillary sinus: 18.3%, mandibular canal: 11.1%, nasal cavity: 6.3%, mental foramen: 5.6%, and incisive canal: 0.4%). Implant fracture and over-drilling were found in 1.6% and 0.8% of cases, respectively. Severity was categorized as mild (9.5%), moderate (35.7%), severe (37.7%), and extreme (17.1%), and 52.4% of implants had inappropriate angulation. Conclusion: CBCT imaging is recommended for detecting dental implant malpositioning. The most common and severe type of malpositioning was buccal cortex perforation.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제11권1호
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• pp.50-62
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• 1989

저자는 1982년 1월부터 1987년 12월까지 대구시내 주의료기관인 5개 종합병원에 입원가료한 바 있는 하악골 골절환자 677명을 대상으로 임상적 연구를 시행한 바 다음과 같은 결과를 얻었다. 발생빈도에 있어서 연도별로는 약간의 증가추세에 있었고, 월별로는 5월과 9월에 호발하였고 지역별로는 대구시(55.7%)가 많았으며 대도시 (63.0%)에서 다소 높았다. 연령별 및 성별에서 20대(38.3%)에서 가장 호발하였으며 10대(18.5%), 30대 (18.0%)의 순으로 나타났으며 남녀비는 4.64 : 1로서 남자에게서 호발하였다. 원인별로 볼때 구타(31.5%), 교통사고 (29.5%)와 추락(15.2%), 전도(15.1%)로 많은 비중을 나타내었으며,별로 보면 20-40시 사이에 구타가 가장 많았다. 골절부위별로는 하악골 단독골절이 95.5%였으며 중안면골 골절이 동반된 경우가 4.5%였으며 골절 부위 수는 총 1,033개로서 1인당 평균 1.53개였으며 정중부(39.8%), 우각부(25.2%), 과두부(22.7%)의 순이었으며 정중부를 제외한 좌우측 비교에서 좌측이 364례로서 우측의 257례보다 많았다. 수상후 24시간이내에 전체의 62.9%가 내원하였으며, 1차 진료기관을 거친 경우가 42.4%였으며 유형별로는 일반의원(44.6%), 일반병원(27.9%) 및 치과의원(25.4%)의 순으로 나타났다. 처치내용별로는 관혈적정복수술이 전체의 55.0%를 차지하였고 37.2%는 비관혈적 정복수술을 받았으며, 소아에서는 주로 비관혈적 정복수술이 50.6%를 차지하였다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제28권3호
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• pp.196-204
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• 2002

For the study of its stability when the screw has been fixed after sagittal split ramus osteotomy(SSRO) of the mandible, the methods of screw arrangement are classified into two types, triangular and straight. The angles of screws to the bone surface are classified as perpendicular arrangements, the $60^{\circ}$ anterioinferior screw, known as triangular, and the most posterior screw, called straight arrangement, thus there are four types. The finite element method model has been made by using a three dimensional calculator and a supercomputer. The load directions are to the anterior teeth, premolar region, and molar region, and the bite force is 1 Kgf to each region. The distribution of stress, the von-Mises yield strength, and safety of margin refer to the total sum of transformed energy have been studied by comparison with each other. The following conclusion has been researched : 1. When shear stress is compared, in the triangular arrangement in the form of "ㄱ", the anterosuperior screw is seen at contributing to the support of the bone fragment. In the straight arrangement, substantial stress is seen to be concentrated on the most posterior angled screw. 2. When the von-Mises yield strength is compared, it seemed that the stress concentration on the angled anteroinferior screw is higher, it shows a higher possibility of fracture than any other screw. In the straight arrangement, stress appeared to be concentrated on the most posteriorly angled screw. 3. When the safety margins of the transfomed energy are compared, the energy conduction is much greater in the case of the angled screw than in the case of the perpendicular screw. The triangular arrangement in the form of "ㄱ" shows a superior clinical sign to that of the straight arrangement. Judging from the above results, when the screw fixation is made after SSRO in practical clinical cases, two screws should be inserted in the superior border of mandibular ramus and a third screw of mandibular inferior border should be inserted in the form of triangular. All screws on the bony surface should be placed perpendicularly-$90^{\circ}$ angles apparently best promote bony support and stability.

• Imaging Science in Dentistry
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• 제30권2호
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• pp.117-122
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• 2000

Fibrous dysplasia is a benign disorder of bone consisting of intramedullary proliferation of fibrous tissue and irregularly distributed, poorly developed bone. The disease manifests itself in the monostotic form in which only one bone is involved and the polyostotic form in which multiple bones at different sites are affected. We reported a extensive case of polyostotic fibrous dysplasia with involvement of craniofacial bones, mandible, ribs and extremities. A 18-year-old man showed remarkable right facial swelling who had been treated on right femur 3 years ago with a bone graft for pathologic fracture and he recognized facial swelling 5 years ago. Extraoral radiograms and computed tomogram showed diffuse sclerosis with a ground glass appearance of the most cranial bones, facial bones. The right mandibular lesion showed very expansile lesion with mottled appearance. Bone scans showed mutifocal increased uptakes in craniofacial bones, right mandible, bilaterally in ribs, humerus, femur, tibia and characteristic varus deformity of right femur (shepherd's crook defomity). This case showed exceptionally bilateral, extensive nature of bone lesion and didn't show any features of skin pigmentation and endocrine disturbances.

• 대한치과의사협회지
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• 제10권4호
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• pp.241-245
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• 1972

The authors have observed a case of adenold cystic carcinoma occured in molar portion of the left mandible in 59-year old woman. The results are as follows: 1. Roentgenographic findings revealed pathological fracture of the left mandibular body. 2. The patient complained of burning sensation of tongue and facial dull pain. 3. Microscopically, in the portion of glandular arrangoment of tumor cells, the mucinous materials were contained, and the mitotic figures of tumor cells did not appear in this case, and the stromal connective tissue revealed hyaline degeneration and myxomatous degeneration. 4. The tumor cells were infiltrated not only perinoural lymphatics, but also perineurum and intraneura tissue.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제15권1호
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• pp.7-10
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• 1993

The final purpose of oral & maxillofacial trauma is functional & esthetic repair. Nowadays, severe trauma involving with the head & neck trauma is increasing. After these trauma occurs, the patients develop similar signs & symptoms with the postoperative healing period, as like thurst, hypertention, excitability, disorientation, convulsion, et al. Because SIADH which is one of important complications after head trauma, shows similar clinical features after operation, we should pay attention to detect it. SIADH shows characteristic laboratory findings, as like hyponatremia, urine hyperosmolality, increased plasma ADH level, continued renal excretion of sodium, so we can easily distinguish it from postoperative conditions. This paper reports two cases, one was the case of the mandibular fracture and cerebral contusion, which included permanent SIADH. The other was the case of the multiple teeth injury and cerebral contusion, which was transient SIADH. We treated them with water restriction, hypertonic saline, and diuretics.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제15권4호
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• pp.269-274
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• 1993

This is the case report of huge complex odontoma treated with sagittal splitting of buccal bone plate and iliac bone graft in left mandible angle. The 22 years old patient was admitted to the department of Oral and Maxillofacial Surgery of Kyungpook National University Hospital with the chief complaint of swelling on the left mandible angle area. We used extra oral Risdon incision and splitted the buccal cortical bone after making the horizontal bone cut buccally. The tumor mass was removed with cutting into the pieces with surgical bur to prevent mandibular fracture. The dead space was grafted with autogenous iliac bone graft and the splitted buccal cortical bone was fixed with two L-type miniplate. After 12months follow up check, we noticed good process of bone healing and satisfactory aesthetic result. In this case, my operative approach provided the excellent surgical access to the hard tissue mass and minimized post operative complication comparing with the conventional surgical approaches.