• Maxillofacial Plastic and Reconstructive Surgery
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• 제33권3호
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• pp.218-224
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• 2011

Purpose: The purpose of this study is to evaluate the post-operative skeletal stability after surgical correction of patients with mandibular prognathism by bilateral sagittal split ramus osteotomy (BSSRO) and to evaluate the horizontal relapse tendency after the surgery. Methods: Twenty-six patients with Class III dental and skeletal malocclusion were selected for this retrospective study. Fifteen of them underwent BSSRO for mandibular setback and eleven of them underwent two-jaw surgery (Lefort I and BSSRO). In each patient, lateral cephalometric radiographs were taken pre-operatively, post-operatively within 1 week, and post-operatively after eight months. After tracing of the cephalometric radiographs, various parameters were measured. The analyses were done by linear measurement to evaluate the change in position of hard tissue B point, pogonion and mandibular plan angle by examination on lateral cephalograms. Results: The horizontal relapse rate was 27.1% at B point and 31.6% at pogonion in patients who underwent BSSRO. The horizontal relapse rate of the group where the amount of correction exceeded 10 mm was 25.69% at B point. Conclusion: There were no statistical differences on the magnitude of setback and direction of rotation of the mandible in mandibular stability. There were also no statistical differences between single mandibular surgery and two-jaw surgery for mandibular stability.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권5호
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• pp.329-334
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• 2009

Objective: To evaluate the ratio between bone-contact length and inter-segmental length of the rigid fixation screw used in bilateral sagittal split ramus osteotomy (BSSRO) for mandibular setback. Material and Methods: Records of 40 patients with Class III malocclusion were selected. 20 of them had BSSRO, while the other 20 had BSSRO with maxillary LeFort I osteotomy. All of the patients had three noncompressive bicortical screws inserted at the gonial angle through transcutaneous approach. Two screws were inserted antero-posteriorly above inferior alveolar nerve and one screw was inserted below. The lengths of bone-contact and that of inter-segmental part were measured using cone-beam computed tomography. Ratio between these two measured lengths was calculated. Results: Both bone-contact and inter-segmental lengths were longer in BSSRO group than in BSSRO with maxillary LeFort I osteotomy group. Ratio of bone-contact to inter-segmental length was lower in BSSRO group than in BSSRO with Lefort I group. Both bone-contact and inter-segmental lengths were longer at the antero-superior position than at the inferior position. However, their ratio showed little difference. Conclusion: This study suggest that stability of screws in BSSRO group was greater than in BSSRO with Lefort I group. Stability of screws at the antero-superior position was greater than at the inferior position. Ratio of bone-contact to inter-segmental lengths was 0.2 in average.

• Journal of Yeungnam Medical Science
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• 제25권2호
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• pp.108-116
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• 2008

Background : When surgeons plan mandible ortho surgery for patients with skeletal class III facial asymmetry, they must be consider the exact method of surgery for correction of the facial asymmetry. Three-dimensional (3D) CT imaging is efficient in depicting specific structures in the craniofacial area. It reproduces actual measurements by minimizing errors from patient movement and allows for image magnification. Due to the rapid development of digital image technology and the expansion of treatment range, rapid progress has been made in the study of three-dimensional facial skeleton analysis. The purpose of this study was to conduct 3D CT image comparisons of mandible changes after mandibular surgery in facial asymmetry patients. Materials & methods : This study included 7 patients who underwent 3D CT before and after correction of facial asymmetry in the oral and maxillofacial surgery department of Yeungnam University Hospital between August 2002 and November 2005. Patients included 2 males and 5 females, with ages ranging from 16 years to 30 years (average 21.4 years). Frontal CT images were obtained before and after surgery, and changes in mandible angle and length were measured. Results : When we compared the measurements obtained before and after mandibular surgery in facial asymmetry patients, correction of facial asymmetry was identified on the "after" images. The mean difference between the right and left mandibular angles before mandibular surgery was $7^{\circ}$, whereas after mandibular surgery it was $1.5^{\circ}$. The right and left mandibular length ratios subtracted from 1 was 0.114 before mandibular surgery, while it was 0.036 after mandibular surgery. The differences were analyzed using the nonparametric test and the Wilcoxon signed ranks test (p<0.05). Conclusion: The system that has been developed produces an accurate three-dimensional representation of the skull, upon which individualized surgery of the skull and jaws is easily performed. The system also permits accurate measurement and monitoring of postsurgical changes to the face and jaws through reproducible and noninvasive means.

• Journal of Korean Dental Science
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• 제10권1호
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• pp.35-44
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• 2017

In case of loss of many teeth due to dental caries or periodontal disease, improvement of masticatory function and aesthetics can be obtained through implant treatment. However, if the patient does not have a normal intercondylar relationship, it is difficult to achieve an ideal occlusal relationship with only prosthetic treatment. In particular, oral reconstruction with orthodontic treatment or orthognathic surgery is necessary for patients with mandibular prognathism. However, if the posterior occlusion collapses due to severe caries or periodontal disease, orthognathic surgery may be difficult. The occlusal vertical stop is very important for the stability of the mandibular position during occlusal reconstruction through orthognathic surgery. The patient in this case had posterior occlusion collapsed due to the caries of a large number of posterior teeth, and showed mandibular prognathism and long face. We planned a full arch restoration with orthognathic surgery and extracted the hopeless teeth. To secure the vertical stop required for orthognathic surgery, the implant was placed before surgery. After the orthognathic surgery and the final prosthesis application, the results were satisfactory for the improvement of the aesthetics and the restoration of the masticatory function.

• 대한치과교정학회지
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• 제43권1호
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• pp.42-52
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• 2013

The aim of this paper was to propose a new method of bimaxillary orthognathic surgery planning and model surgery based on the concept of 6 degrees of freedom (DOF). A 22-year-old man with Class III malocclusion was referred to our clinic with complaints of facial deformity and chewing difficulty. To correct a prognathic mandible, facial asymmetry, flat occlusal plane angle, labioversion of the maxillary central incisors, and concavity of the facial profile, bimaxillary orthognathic surgery was planned. After preoperative orthodontic treatment, surgical planning based on the concept of 6 DOF was performed on a surgical treatment objective drawing, and a Jeon's model surgery chart (JMSC) was prepared. Model surgery was performed with Jeon's orthognathic surgery simulator (JOSS) using the JMSC, and an interim wafer was fabricated. Le Fort I osteotomy, bilateral sagittal split ramus osteotomy, and malar augmentation were performed. The patient received lateral cephalometric and posteroanterior cephalometric analysis in postretention for 1 year. The follow-up results were determined to be satisfactory, and skeletal relapse did not occur after 1.5 years of surgery. When maxillary and mandibular models are considered as rigid bodies, and their state of motion is described in a quantitative manner based on 6 DOF, sharing of exact information on locational movement in 3-dimensional space is possible. The use of JMSC and JOSS will actualize accurate communication and performance of model surgery among clinicians based on objective measurements.

• Restorative Dentistry and Endodontics
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• 제12권1호
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• pp.119-129
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• 1986

The purpose of this study was to evaluate the marginal leakage of glass ionomer cement with different cavosurface margins. 192 class V cavities were prepared on freshly extracted non-carious teeth and glass ionomer cement were inserted according to the manufacturer's instructions. Cavity preparations for this investigation were performed in four groups. The experimental specimens were made by packing the glass ionomer cement (Fuji Ionomer Type II G-C Co. Japan) into the prepared 192 cavities of four groups with different modes: Group I. - The 48 cavities with $90^{\circ}$ butt-joint cavosurface preparation and restored with glass ionomer cement. Group II. - The 48 cavities with butt-joint preparation modified by $135^{\circ}$ beveling the cavosurface in the dentin and restored with glass ionomer cement. Group III. - The 48 cavities with butt-joint preparation modified by cutting a chamfer in the dentin and restored with glass ionomer cement. Group IV. - The same 48 cavities as group I, and overfilled with glass ionomer cement beyond the cavosurface angle. And four groups above described divided into three subgroups by means of conditioning the cavity walls: Control group. - Glass ionomer cement filled in the prepared 64 cavities after being cleaned with a stream of tap water. Phosphoric acid treatment group. - Glass ionomer cement filled in the prepared 64 cavities after being conditioned with a 50% phosphoric acid. Citric acid treatment group. - Glass ionomer cement filled in the prepared 64 cavities after being conditioned with a 50% citric acid. All 192 specimens were immersed in the 2.0% basic fuchsin solution and subjected to thermal stress at one-minute intervals ($4{\pm}2^{\circ}C$ to $60{\pm}2^{\circ}C$) for 70 minutes before exposure to the dye. The specimens were sectioned ecclesiologically through the center of the restorations for different periods of immersion time, 24 hours, 7 days, 14 days 30 days. The sections were examined under a stereoscopic microscope. The results were as follows: 1. The degree of marginal leakage in group II and III was greater than that in group I and IV. 2. The degree of marginal leakage in phosphoric acid treatment group was similar with that in control group. 3. The degree of marginal leakage in citric acid treatment group was less than that in control group. 4. In all groups, the degree of marginal leakage in phosphoric acid treatment group was greater than that in citric acid treatment group. 5. There is no statistical difference of the degree of marginal leakage according to the immersion time in the dye solution.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제13권1호
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• pp.117-127
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• 1991

현대 사회에서 외상의 특성은 다발성 손상이 빈발하는 것이며 상악골절시 생명을 위협하는 다발성 전신손상이 동반되면 수술이 지연되어 골절부의 지연된 부정유합을 보일 수 있다. 또한 골절된 양상에 따라서는 관혈적 정복술의 적용여부가 고려되는데 특히 골절편의 분쇄가 심하면 수술시 골절부위의 이개 후 정상위치로의 이동이 어렵고 설사 골절편의 이동이 이루어졌다고 하여도 정상위치로의 고정이 용이하지 않을 뿐만 아니라 분쇄골절편의 상실량이 많아지면 골이식까지 시행해야 하는 등 외과적이술식의 적용에 많은 난관이 예상된다. 따라서 상악골절 후 통상 6주일 간의 시간경과가 없다면 오히려 상악골절편의 이동방향을 예측하여, 전방견인용 headgear 또는 headcap 을 사용한 교정적인 치료를 시도함이 바람직할 수도 있다. 더우기 reverse headgear를 이용한 치료법은 골절된 경우가 아니더라도 상악골의 전방이동에 유용함이 실험적으로나 임상적으로 입증된 만큼 이를 상악골절후 후퇴된 상악골의 전방견인에 적용할 경우 교정치료의 최대장애인 cortical bone의 연속성이 골절로 인해 끊어지고 섬유성 유착상태로 남게되어 교정력의 효과가 치아이동 뿐만 아니라 골편의 이동에 매우 유익하리라 사료된다. 이에 저자는 상악골적이 분쇄양상인 한 환자에서 headgear와 headcap을 이용한 교정치료법을 5개월간 적용해 양호한 결과를 얻었고, 골절양상이 분쇄형이 아닌 증례에서는 외상후 5주간 경과 되었지만 관혈적 정복술을 시행하여 정상교합을 회복했으며, 심한 두부 손상으로 6개월만에 의식 회복을 한 LeFort I, II, III, 환자에서는 두부방사선 계측학적 분석, 교합기 상에서의 모형분석, 전산화 단층촬영 검사 등을 시행한 후 새로운 골면에다 LeFort I -osteotomy with iliac bone graft를 시행해 정상교합 및 안모추형을 개선시켰기에 이를 보고한다.

• 대한소아치과학회지
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• 제40권4호
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• pp.296-305
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• 2013

본 연구는 청소년을 대상으로 부정교합 요소들의 유병률을 조사하고 각 요소와 자존감의 연관성을 평가할 목적으로 시행되었다. 양산시 소재 3개 중학교에 재학 중인 1,380명을 대상으로 부정교합 요소별 유병률과 자존감 상태를 조사 분석하여 다음과 같은 결과를 얻었다. Angle 분류에 의한 제1대구치 관계는 I, II 및 III급 교합이 각각 69.0%, 19.4%, 10.6%로 나타났다. 수평피개는 정상 86.9%, 반대교합 5.6%, 큰 수평피개 6.6%, 극심히 큰 수평피개 0.8%로 나타났다. 수직피개는 정상 94.1%, 과개교합 4.7%, 개방교합 1.2%였다. 정중선 불일치는 0~1 mm는 98.2%, 2~4 mm는 1.4%, 5 mm 이상은 0.4%였다. 총생은 상, 하악에 총생이 있는 경우가 각각 9.6%, 14.1%, 양악 모두의 경우가 24.1%였으며, 치간공극은 상, 하악에만 있는 경우가 각각 3.0%, 2.4%, 양악 모두의 경우는 1.7%였다. 부정교합 요소별 자존감의 차이는 여자의 경우, 반대교합과 개방교합 그룹에서 자존감 지수가 낮은 값을 보였다(p < 0.05).

• 대한치과교정학회지
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• 제30권1호
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• pp.33-41
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• 2000

성장기 아동에서의 골격성 III급 부정교합을 치료하기 위하여 사용되는 이모장치는 하악골의 후하방 회전 또는 하악골 길이 성장의 억제에 의하여 하악 전돌감을 감소시키는 것으로 알려져 있다. 그러나 이에 관한 연구는 하악골 성장의 주요 부분을 담당하는 하악 과두부위와 관련된 것이 대부분이었다. 본 연구는 장기간 이모장치를 착용하였을 때 구외력이 직접 적용되는 부위인 하악 이부의 형태 변화를 평가하기 위해 시행하였다. 전북대학교병원 치과교정과에서 교정치료를 받은 혼합치열기 아동 62명 (이모장치군 32명, 대조군 30명)을 대상으로 측모 두부규격 방사선사진을 채득하여(치료 또는 관찰기간 평균 2.1년) 계측치 (각도 4개 거리 5개, 비율 2개)를 평가하여 다음과 같은 결론을 얻었다. 1. 치료 후 symphysis height는 이모장치를 사용하지 않은 군과 이모장치 착용군에서 모두 치료 전보다 증가하였다. symphysis depth는 이모장치를 사용하지 않은 군에서 치료 후 증가하였으나 이모장치 착용군에서는 치료 전과 차이가 없었다. 특히, posterior symphysis depth가 이모장치 착용군과 대조군에서 모두 감소한 반면, anterior symphysis depth는 대조군에서는 증가하였고 이모장치 착용군에서는 치료 후 감소하는 경향을 보였다. 2. chin depth와 chin curvature는 이모장치를 사용하지 않은 군에서는 증가하였으나 이모장치 착용군에서는 치료 후에도 변화를 보이지 않았거나 감소하였다. 대조군에서 chin angle, menton angle, symphysis angle은 감소하는 경향을 보였으나 이모장치 치료군에서는 오히려 증가하였다. 이것은 하악골의 성장에 따라 정상적으로 나타나는 pogonion 부위의 골침착이 이모장치 착용군에서 chincup의 직접 접촉에 의해서 억제된 결과로 생각된다. 3. 성장기 아동에서 이모장치를 착용하였을 때 하악 이부의 전방 성장 억제에 의하여 치료 전과 유사한 하악 이부 형태가 유지되었으며 이것은 주로 하악 이부의 전방부의 골침착 억제에 의한 결과인 것으로 생각된다.

• 대한치과교정학회지
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• 제29권2호
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• pp.251-265
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• 1999

환자의 진단이나 치료계획 수립 및 치료의 결과를 평가하기 위해서 현재까지 여러 가지 수평 기준선들이 사용되고 있으나 그 정확성과 재현성이 문제가 되고 있으며 기존의 연구도 서양인을 대상으로 한 수평 기준선을 사용한 경우가 대부분이다. 특히 성장이 완료된 후의 상태를 평가하는 성인 환자와는 다르게 성장기 아동에서는 발육단계에 따라 수평 기준선이 변화될 수 있으므로 이를 고려한 수평 기준선의 설정이 필요할 것이다. 이에 본 연구에서는 성장기 아동의 골성숙도와 부정교합군 및 성별에 따른 Sella-Nasion (SN) 평면과 Frankfort-Horizontal(FH)평면이 이루는 각도와 FH평면과 다른 수평면 간의 관계를 조사하기 위해 교정치료를 받은 경험이 없는 성장기 남녀 아동 540명을 대상으로 수완부골 방사선 사진과 측모두부 방사선 사진을 촬영하였으며, SMA(Skeletal Maturity Assessment)를 이용하여 골성숙도에 따라 SMI 1-4를 A군, SMI 5-7을 B군, SMI 8-11을 C군으로 분류하고, 측모두부규격 방사선 사진 계측결과 부정교합 분류에 따라 골격성 I급 부정교합군, 골격성 II급 부정교합군, 골격성 III급 부정교합군의 세 군으로 분류한 후 10개의 항목을 평가하여 다음과 같은 결론을 얻었다. 1 SN 평면과 FH 평면이 이루는 각도는 골성숙도와 부정교합 및 성별에 따른 차이를 보이지 않았다. 2. SN 평면과 FH 평면이 이루는 각도는 남자는 $8.27^{\circ}{\pm}2.31^{\circ}$, 여자는 $8.59^{\circ}{\pm}2.24^{\circ}$, 전체에서는 $8.42^{\circ}{\pm}2.28^{\circ}$였다. 3. FH 평면과 구개평면이 이루는 각은 골성숙도, 부정교합 및 성별에 따른 차이를 보이지 않고 비교적 일정하였다. ($1.09^{\circ}{\pm}3.21^{\circ}$).