• Restorative Dentistry and Endodontics
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• 제40권2호
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• pp.161-165
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• 2015

Three-dimensional (3D) reconstruction of cone-beam computed tomography (CBCT) scans appears to be a valuable method for assessing pulp canal configuration. The aim of this report is to describe endodontic treatment of a mandibular second premolar with aberrant pulp canal morphology detected by CBCT and confirmed by 3D modeling. An accessory canal was suspected during endodontic treatment of the mandibular left second premolar in a 21 year old woman with a chief complaint of pulsating pain. Axial cross-sectional CBCT scans revealed that the pulp canal divided into mesiobuccal, lingual, and buccal canals in the middle third and ended as four separate foramina. 3D modeling confirmed the anomalous configuration of the fused root with a deep lingual groove. Endodontic treatment of the tooth was completed in two appointments. The root canals were obturated using lateral compaction of gutta-percha and root canal sealer. The tooth remained asymptomatic and did not develop periapical pathology until 12 months postoperatively. CBCT and 3D modeling enable preoperative evaluation of aberrant root canal systems and facilitate endodontic treatment.

• 대한소아치과학회지
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• 제33권4호
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• pp.722-727
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• 2006

치아가 정상적으로 맹출해야 하는 시기를 지나서도 골조직 내에서 맹출하지 않을 수 있으며, 이러한 치아를 매복치라 한다. 유치의 매복은 드물게 나타나며, 더구나 과거의 문헌 고찰에 의하면 현재까지 보고된 계승 영구치 하방에 매복된 유치는 극히 드물다. 대부분의 경우 매복된 유치는 제 2 유구치이다. 유치의 매복에 대한 병인은 유치 치배의 비정상적인 발달로 인해 조기에 유착이 일어나는 것으로 추측되어지고 있으나, 아직까지 정확하게 밝혀진 바는 없다. 전위는 동일한 사분악 내의 인접한 두 개 치아의 위치가 서로 바뀐 것을 말하며, 영구 상악 견치와 제 1소구치 사이에 가장 많이 발생한다. 그 빈도는 1% 내외로 낮으며, 특히 유치열의 전위는 거의 발표된 바가 없다. 본 증례는 양악 양측 제 2유구치의 매복을 주소로 본과에 의뢰된 환자의 구강 및 방사선 검사 결과 매복된 제 2유구치와 후속 제 2소구치 사이의 수직 전위가 관찰되었기에 보고하는 바이다.

• 대한치과보철학회지
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• 제31권2호
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• pp.271-300
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• 1993

The purpose of this study was to analyze the stress distribution at supporting bone according to the types of connection modality between implant and tooth in the superstrcture. This investigation evaluated the stress patterns in a photoelastic model produced by three different types of dental implants such as Branemark, Steri-Oss, IMZ and resin tooth using the techniques of quasi three dimensional photoelasticity. The teeth-supported bridge had a first molar pontic supported by second premolar and second molar as a control group. The implant and toothsupported bridge had a first molar pontic supported by second premolar and implant posterior retainer as an experimental group. Prostheses were mechanically connected to an adjacent second premolar by the rigid of nonrigid connection, Nonrigid connection used an attachment placed between the tooth-supported and fixture-supported component. The female(keyway) of attachment was placed on the distal end of the retainer supported by the tooth ; the male(Key) of attachment connected to the osseointegrated bridge was engaged into the keyway. All prostheses were casted in the same nonprecious alloy and were cemented and screwed on their respective abutments and implants. 16㎏ of vertical loads on central fossae of second premolar, first molar pontic, implant of second molar were applied respectively and 6.5㎏ of inclined load on middle buccal surface of first molar pontic was applied. The results were as follows : 1. Under the vertical load on the central fossa of first mloar pontic, the stress developed at the apex of tooth of implat was more uniformly distributed in the case of nonrigid connection than in the case of rigid connection. 2. Under the vertical load on the central fossa of first molar pontic, the stress developed around the cervical area of tooth of implant was larger in the case of rigid connection than in the case of nonrigid connection because the bending moment was more occured in the case of rigid connection than in the case of nonrigid connection. 3. Stress was more restricted to the loaded side of nonrigid connection than to that of rigid connection 4. Under the inclined load. The set screw loosening of implant was more easily occured in the case of nonrigid connection than in the case of rigid connection due to torque moment. 5. In the case of Branemark implant, the stress concentration in second premolar was larger and the stress developed around the cervical area of implant was lower than any other cases under the vertical load, because Branemark implant with the flexible gold screw was showed in incline toward second premolar by a bending moment. 6. The stress developed around the apex of tooth or implant was more uniformly distributed in the case of Steri-Oss implant with stiff screw than in the case of Branemark implant under the vertical load. But, the stress developed around the cervical area of the Steri-Oss implant was larger than that of any other implants because bending moment was occured by vertical migration of second premolar. 7. The stress distribution in the case of IMZ implant was similar to the case of natural teeth under small vertical load. But, the residual stress around the implant was showed to occurdue to deformation of IMC and sinking of screw under larger vertical load.

• 대한치과보철학회지
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• 제36권2호
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• pp.302-322
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• 1998

This study was accompolished to analyze and compare the number and area of the occlusal contact points in healthy volunteers and athletes with normal occlusion. For this study, 15 athletes(13 amles and 2 females with average age 20) and 21 healthy volunteers(14 mles and 7 females with average age 20.09) were selected. The visual display acquired by scanning of occlusal record in maximal intercuspation was converted into 16 gray value image. Then, using computer program(J & Lee Occlusal Analyser), the pixel which was in definite range of the gray value was recognized, and the numbers of recognized pixel were calculated to area. The results were as follows ; 1. The average numbers of total occlusal contact feints were 31.05 in control group, and 34.67 in athlete group. The average area of total occlusal contacts was $100.25mm^2$ in control group, and $127.78mm^2$ in athlete group. 2. In control group, the average numbers of occlusal contact points were revealed in order as follows ; the first molar(8.48), the second molar(8.24), the second premolar(4.71), the lateral incisor(2.90), the first premor(2.43), the central incisor(2.19), and the canine(2.1). The least average in canine(2.1) was similar to the average(2.19) in central incisor and (2.09) in lateral incisor. In athlete group, the average numbers of occlusal contact points were revealed in order as follows ; the first molar(8.97), the second molar(8.47), the second premolar(5.60), the canine(3.80), the lateral incisor(3.33), the first premolar(2.67), and the central incisor(1.93). 3. In control group, the average areas of occlusal contact surface were revealed in order as follows ; the first molar($39.47mm^3$), the second molar($37.54mm^3$), the second premolar($9.54mm^3$) the first premolar($6.18mm^3$), canine($3.49mm^3$), the central incisor($2.76mm^3$), and the lateral incisor($1.28mm^3$). In athlete group, the average areas of occlusal contact surface were revealed in order as follows ; the first molar($44.11mm^3$), the second molar($40.69mm^3$), the second premolar($16.50mm^3$), the first premolar($9.39mm^3$), the canine($5.08mm^3$), the lateral incisor($3.7mm^3$), and the central incisor($2.25mm^3$). 4. With aging in both control and athlete group, there was a decreasing tendancy in average number of occlusal contact point, and was an increasing tendancy in average area of occlusal contact surface. In comparison at each age, both the numbers and area of occlusal contact were greater in athlete group than in control group. It was not significant in the numbers of occlusal contact points beween athlete and control group(p>0.1), but significant in the area of occlusal contact surface(p<0.03). 5. In comparision as to the kind of sports(Gymnastics : 2, Rugby : 3, Soccor : 5, Ice hocky : 5), the numbers of occlusal contact points were the most in ice hocky, and the area of occlusal contact surface was the greatest in gymnastics. With increasing a career in athlete group, there was a decreasing tendancy in average numbers of occlusal contact points and was an increasing tendancy in average area of occlusal contact surface. 6. By T-scan analyzing, the contact numbers on the anterior teeth were greater in control group than in athlete group, and on the posterior teeth were greater in athlete group than in control group. And the results acquired by T-scan were lesser than that caquired by the silicone bite records. It was not significant in the posterior teeth, but significant in the anterior teeth. In T-scan records, the numbers of occlusal contact points on second molar were the greatest, but in the silicone records, the numbers on first molar were the greatest.

• Journal of Periodontal and Implant Science
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• 제38권1호
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• pp.15-22
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• 2008

Purpose: The attachment level is strongly associated with tooth loss and provides useful information on patterns of destruction of the periodontium. The presence of horizontal attachment loss would not be detected in clinical measurement. Therefore, the purpose of the present study was to estimate the patterns of periodontal destruction based on the attachment area and horizontal attachment loss in extracted teeth due to severe periodontitis. Materials and Methods: 307 teeth satisfied the criteria for assessment. An indirect method, based on digital images obtained from a digital camera and an image analysis program, was used to calculate the area of root surface and attachment loss and the extent of horizontal attachment loss. The data were analysed using SPSS. Results: No statistically significant differences among root surfaces were observed in anterior teeth on the loss of attachment area. However, in posterior teeth statistically significant differences in palatal surfaces of maxillary and mandibular premolar and molar surfaces compared with buccal surfaces were observed. Horizontal attachment loss was observed in 21.5% of the teeth examined. Frequency of horizontal attachment loss was highest in the maxillary first premolar (34.8%), followed by the maxillary second premolar (27.3%) and maxillary canine (25%). The mean length of horizontal attachment loss was 1.5mm. Conclusion: More meticulous examination will be needed of the palatal surfaces of maxillary and mandibular premolar and molar teeth. The percentage of teeth with horizontal attachment loss greater than 2.1 mm was 5.2%. Considering the length of curette blades, about 5.2% of teeth were not properly debrided. Therefore, Additional supportive therapy such as local drug delivery has to be considered in treatment of the first maxillary, second premolar and canine due to the high prevalence of horizontal attachment loss.

• Imaging Science in Dentistry
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• 제52권4호
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• pp.365-373
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• 2022

Purpose: This study investigated whether the relationship between the maxillary sinus and the root of the maxillary premolar is correlated with the root position and whether there is a difference in the long axis angle of premolars and the buccal bone thickness according to the sinus-root relationship and root position. Materials and Methods: Cone-beam computed tomographic images of 587 maxillary first premolars and 580 second premolars from 303 patients were retrospectively reviewed. The maxillary sinus floor-root relationship was classified into 4 types, and the root position in the alveolar bone was evaluated as buccal, middle, or palatal. The long axis angle of the maxillary premolars in the alveolar bone and the buccal bone thickness were measured. The correlation between these parameters was analyzed. Results: The maxillary sinus floor-root relationship showed a statistically significant correlation with the root position in the alveolar bone. Most maxillary first premolars were buccally located, and more than half of the second premolars had their roots in the middle. The long axis angle of the premolars was significantly larger in buccal-positioned teeth than in middle-positioned teeth, and the buccal bone was thinner. Conclusion: When the root of the maxillary premolar was separated from the sinus floor, the premolar was often located on the buccal side. Most of the maxillary first premolars had a thinner buccal bone and larger inclination than the second premolars. It is recommended to evaluate the root position, sagittal angle and buccal bone thickness using CBCT for implant treatment planning.

• 구강회복응용과학지
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• 제18권4호
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• pp.235-249
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• 2002

This study was accompolished to analyze and compare the number and area of the occlusal contact points in healthy volunteers and athletes with normal occlusion. Before the study, 89 athletes(sports career:8.6 years, average age 20) at Kyung Hee University were selected, and survey was accomplished for athlete's recognition about sports dentistry. For this study, 15 athletes(13 amles and 2 females with average age 20) and 21 healthy volunteers(14 mles and 7 females with average age 20.09) at Kyung Hee University were selected. The visual display acquired by scanning of occlusal record in maximal intercuspation was converted into 16 gray value image. Then, using computer program(J & Lee Occlusal Analyser), the pixel which was in definite range of the gray value was recognized, and the numbers of recognized pixel were calculated to area. The results were as follows : (1) On the survey about sports dentistry, 28% of 89 athletes didn't agree that human occlusion may be important, and 30% didn't have any idea of the influence of human occlusion during their sports activities. (2) The average numbers of total occlusal contact points were 31.05 in control group, and 34.67 in athlete group. The average area of total occlusal contacts was $100.25mm^2$ in control group, and $127.78mm^2$ in athlete group. (3) In control group, the average numbers of occlusal contact points were revealed in order as follows; the first molar(8.48), the second molar(8.24), the second premolar(4.71), the lateral incisor(2.90), the first premor(2.43), the central incisor(2.19), and the canine(2.1). The least average in canine(2.1) was similar to the average(2.19) in central incisor and (2.09) in lateral incisor. In athlete group, the average numbers of occlusal contact points were revealed in order as follows; the first molar(8.87), the second molar(8.47), the second premolar(5.60), the canine(3.80), the lateral incisor(3.33), the first premolar(2.67), and the central incisor(1.93). (4) In control group, the average areas of occlusal contact surface were revealed in order as follows; the first molar($39.47mm^3$), the second molar($37.54mm^3$), the second premolar($9.54mm^3$) the first premolar($6.18mm^3$), canine($3.49mm^3$), the central incisor($2.76mm^3$), and the lateral incisor($1.28mm^3$). In athlete group, the average areas of occlusal contact surface were revealed in order as follows; the first molar($44.11mm^3$), the second molar($40.69mm^3$), the second premolar($16.50mm^3$), the first premolar($9.39mm^3$), the canine($5.08mm^3$), the lateral incisor($3.7mm^3$), and the central incisor($2.25mm^3$). (5). With aging in both control and athlete group, there was a decreasing tendancy in average number of occlusal contact point, and was an increasing tendancy in average area of occlusal contact surface. In comparison at each age, both the numbers and area of occlusal contact were greater in athlete group than in control group. It was not significant in the numbers of occlusal contact points beween athlete and control group(p>0.1), but significant in the area of occlusal contact surface(p<0.05). (6) In comparision as to the kind of sports(Gymnastics:2, Rugby:3, Soccor:5, Ice hocky:5), the numbers of occlusal contact points were the most in ice hocky, and the area of occlusal contact surface was the greatest in gymnastics. With increasing a career in athlete group, there was a decreasing tendancy in average numbers of occlusal contact points, and was an increasing tendancy in average area of occlusal contact surface.

• Imaging Science in Dentistry
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• 제43권2호
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• pp.71-75
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• 2013

Purpose: This study was performed to determine the position of the mental foramen relative to the apices of the teeth based on panoramic radiographs in a Moroccan population. We also analyzed gender differences and the symmetry of location within individuals. Materials and Methods: Seven hundred ninety-four panoramic radiographs were evaluated with regard to the location and symmetry of the mental foramina in male and female subjects. The results were analyzed using Pearson's ${\chi}^2$ and Fisher's exact test. Results: Of the 794 panoramic radiographs, 377 met the inclusion criteria for at least one side. The mental foramen was located just below the apex of the second premolar in 62.7% of the patients and between the first and second premolars in 30%. It was symmetrically located in 79%. No statistically significant differences were found between males and females in the position and symmetry of the mental foramen. Conclusion: The most common position for the mental foramen in this sample was in line with the second premolar.

• 한국임상수의학회지
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• 제20권1호
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• pp.134-137
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• 2003

A 5-year-old, male mixed breed dog was presented to Gyeongsang National University Animal Hospital for bilateral mandibular open fracture by bite. The dog had loss of the teeth and injury of the oral mucosa. Radio-graphic and blood examinations were conducted. Fracture lines were observed between first premolar and second premolar, but temporomandibular luxation was not observed on radiographs. In serum analysis, elevated levels of CPK and LDH were found. The dog was anesthetized and prepared for aseptic surgery. Acrylic external skeletal fixator with Kirschiner wire was applied. Pin loosening and malalignment of the right fracture line was observed at 7 weeks after surgery. We applied Kirschner-Ehmer fixator and half pins during the second surgical procedure. At 4 weeks after a second surgical procedure, the fixator and pins were removed from mandible. The fractures were healed with no complications.

• 대한치과교정학회지
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• 제31권1호
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• pp.1-13
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• 2001

성장기 환자에서 치아의 배열이나 입술의 외형을 개선하거나 경미한 악골 부조화에 의한 부정교합을 절충(camouflage)하기 위하여 발치가 적용될 수 있는데, 하악 치열궁에 총생의 양이 미약하거나 전치부 분절을 과도하게 후방견인 시킬 필요가 없는 경우 하악 제 2소구치 발치를 계획할 수 있다. 그러나, 성장기 환자에서 이러한 제 2소구치 발치의 기준과 치료에 의한 상, 하악 치아의 이동양상에 대한 연구는 부족한 실정이다. 본 연구는 상, 하악 소구치 발치를 통한 포괄적 교정치료를 시행한 성장기 환자를 대상으로 상악 제 1소구치와 하악 제 1 소구치를 발치한 군(4/4발치군, 14명)과 상악 제 1 소구치, 하악 제 2 소구치를 발치한 군(4/5발치군, 15명)의 치료 전, 후의 측모두부규격방사선사진을 비교하여 하악 제 2소구치 발치의 적응증에 대한 진단기준을 평가하고, 안정골 구조물을 참고한 중첩법을 이용하여 치아이동에 어떠한 차이가 있는지를 평가하여 다음과 같은 결론을 얻었다. 1. 4/4발치군과 4/5발치군은 치료 전 계측치에서 교합평면에 대한 상악전치의 치축각도, 구치부 교합관계, IMPA 그리고 interincisal angle에서 차이를 나타내었다. 2. 하악 제 1 대구치의 전방 이동량은 4/5 발치군에서 더 전방이동 되는 경향을 나타내었다(p<0.05). 3. 치료 전, 후의 상악 치아의 이동양상은 4/4 발치군과 4/5 발치군 사이에 차이가 없었다(p<0.05).