• 대한치과교정학회지
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• 제29권1호
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• pp.129-136
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• 1999

유착, 부적절한 교정치료, 과잉치, 낭종, 비정상적인 맹출경로등의 국소적인 원인으로 인하여 구치부의 매복이 발생할 수가 있다. 매복치는 적절한 치료를 하지 않으면, 교합기능의 상실, 영구치의 상실, 대합치의 정출, 인접치의 치근흡수등을 야기 할 수가 있다. 매복치를 성공적으로 맹출유도하기 위해서는 매복치의 치근형성여부가 중요한 요소가 되며, 매복치의 치근형태, 주위환경등을 유의한 적절한 교정력이 가해져야 한다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제36권2호
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• pp.119-124
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• 2010

Introduction: Surgical extraction of third molar is one of the most frequently performed procedures in oral and maxillofacial surgery unit as the impacted wisdom teeth could cause various complications. Even though, however, extraction of the impacted wisdom teeth is an obligation for the reason of possible complication even for general practitioners, it has been avoided. Various factors concerning surgical extraction of impacted third molar are considered: general condition of patients, relationship with relative anatomies, aspects of impaction, surgeon's skill. Materials and Methods: The consideration and crossing analysis of these factors with 2,463 patients who visit Dankook University dental hospital to extract those impacted third molar. Results: 1. Gender doesn't affect. 2. Medical problems have more complications. 3. There are more complications in high difficulty index (DI) impacted teeth. 4. When inferior alveolar canal overlap mandibular third molar, complication rate is 26.92%. 5. The most common complication was swelling and pain. 6. There is no statistical difference between the incidence of complication and surgeon's experience. Conclusion: In regard to these results, it seems that clinical or radiological examination can predict potential complications of wisdom teeth, and it is helpful to bear in mind the fact.

• Imaging Science in Dentistry
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• 제43권4호
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• pp.289-293
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• 2013

Purpose: This study was performed to determine the relationship between the stage of tooth eruption (both vertical and mesio-angular) and chronological age. Materials and Methods: Indirect digital panoramic radiographs were used to measure the distances from the dentinoenamel junction (DEJ) of the second molars to the occlusal plane of the second molar teeth and of the adjacent third molars in 264 Thai males and 437 Thai females using ImageJ software. The ratio of those distances was calculated by patient age, and the correlation coefficient of the ratio of the third molar length to the second molar length was calculated. Results: The correlation between the height of the vertically erupted upper third molar teeth and age was at the intermediate level. The age range of ${\geq}15$ to <16 years was noted to be the range in which the correlation between the chronological age determined from the eruptional height and actual chronological age was statistically significant. The mean age of the female subjects, in which the position of the right upper third molar teeth was at or above the DEJ of the adjacent second molar but below one half of its coronal height was $19.9{\pm}2.6$ years. That for the left side was $20.2{\pm}2.7$ years. The mean ages of the male subjects were $20.1{\pm}3.3$ years and $19.8{\pm}2.7$ years for the right and left sides, respectively. Conclusion: It might be possible to predict chronological age from the eruption height of the wisdom teeth.

• Journal of Korean Dental Science
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• 제3권2호
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• pp.12-19
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• 2010

Despite the latest advancement made in its techniques and devices/apparatuses and the resulting rising expectation in the field of dental surgery, apicoectomy performed in the molar teeth remains a technical challenge and lacks evidence substantiated by long-term follow-up studies. This study sought to investigate the treatment outcomes and post-operative success rate in the root-end resected molar teeth accompanied by a high level of surgical risks due to their close proximity to the mandibular canal and maxillary sinus. A total of 68 patients who received treatment at Livingwell Dental Hospital between 2004 and 2010 and underwent apical surgery in the maxillary or mandibular molar area were enrolled in this study. A total of 160 roots collected from 75 molar teeth were subjected to surgical endodontic treatment and subsequently evaluated clinically as well as radiographically. Based on the results of the study, the clinical success rate was found to be 78.8% in cases involving radiological healing. Likewise, 90.7% of the roots recorded a robust clinical survival rate, but with incomplete healing as shown by radiography. The results indicate that the apical procedure involving molar teeth is a prognosis-friendly method that promises positive outcomes and higher success rate based on long-term follow-up observations.

• The Journal of Advanced Prosthodontics
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• 제12권1호
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• pp.1-8
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• 2020

PURPOSE. To investigate the influence of crown material (lithium-disilicate, 3Y-TZP zirconia) and abutment type (rigid implant, resin tooth with artificial periodontium) on wear performance of their antagonist teeth and adjacent teeth. MATERIALS AND METHODS. A mandibular left first molar (#36) with adjacent human teeth (mandibular left second premolar: #35, mandibular left second molar: #37) and antagonistic human teeth (maxillary left second premolar: #25, maxillary left first molar: #26, maxillary left second molar: #27) was prepared simulating a section of the jaw. Samples were made with extracted human molars (Reference), crowned implants (Implant), or crowned resin tooth analogues (Tooth). Crowns (tooth #36; n = 16/material) were milled from lithium-disilicate (Li, IPS e.max CAD) or 3Y-TZP zirconia (Zr, IPS e.max ZirCAD, both Ivoclar Vivadent). Thermal cycling and mechanical loading (TCML) in the chewing simulator were applied simulating 15 years of clinical service. Wear traces were analyzed (frequency [n], depth [㎛]) and evaluated using scanning electron pictures. Wear results were compared by one-way-ANOVA and post-hoc-Bonferroni (α = 0.05). RESULTS. After TCML, no visible wear traces were found on Zr. Li showed more wear traces (n = 30-31) than the reference (n = 21). Antagonistic teeth #26 showed more wear traces in contact to both ceramics (n = 27-29) than to the reference (n = 21). Strong wear traces (> 350 ㎛) on antagonists and their adjacent teeth were found only in crowned groups. Abutment type influenced number and depth of wear facets on the antagonistic and adjacent teeth. CONCLUSION. The clinically relevant model with human antagonistic and adjacent teeth allowed for a limited comparison of the wear situation. The total number of wear traces and strong wear on crowns, antagonistic and adjacent teeth were influenced by crown material.

• The Journal of Advanced Prosthodontics
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• 제6권6호
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• pp.468-473
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• 2014

PURPOSE. This study aimed to evaluate the accuracy of digitizing dental impressions of abutment teeth using a white light scanner and to compare the findings among teeth types. MATERIALS AND METHODS. To assess precision, impressions of the canine, premolar, and molar prepared to receive all-ceramic crowns were repeatedly scanned to obtain five sets of 3-D data (STL files). Point clouds were compared and error sizes were measured (n=10 per type). Next, to evaluate trueness, impressions of teeth were rotated by $10^{\circ}-20^{\circ}$ and scanned. The obtained data were compared with the first set of data for precision assessment, and the error sizes were measured (n=5 per type). The Kruskal-Wallis test was performed to evaluate precision and trueness among three teeth types, and post-hoc comparisons were performed using the Mann-Whitney U test with Bonferroni correction (${\alpha}=.05$). RESULTS. Precision discrepancies for the canine, premolar, and molar were $3.7{\mu}m$, $3.2{\mu}m$, and $7.3{\mu}m$, respectively, indicating the poorest precision for the molar (P<.001). Trueness discrepancies for teeth types were $6.2{\mu}m$, $11.2{\mu}m$, and $21.8{\mu}m$, respectively, indicating the poorest trueness for the molar (P=.007). CONCLUSION. In respect to accuracy the molar showed the largest discrepancies compared with the canine and premolar. Digitizing of dental impressions of abutment teeth using a white light scanner was assessed to be a highly accurate method and provided discrepancy values in a clinically acceptable range. Further study is needed to improve digitizing performance of white light scanning in axial wall.

• Journal of Oral Medicine and Pain
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• 제18권1호
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• pp.107-117
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• 1993

The author has taken intraoral standard films by the paralleling technique of 6414 teeth in 838 patients ranged from early twenties to early sixties and analysed the change of pulp cavity in the mandibular posterior teeth by ageing. The obtined results were as follows : 1. There was no significant difference between the right and left teeth. 2. The degree of change of pulp cavity in female was higher than that in male. 3. The change of pulp cavity was increased by ageing. 4. The correlation between the degree of change of pulp cavity inmandibular posterior teeth (X) and age (Y) were : Male 1st premolar Y=13.22X3.37+ r=0.79 2nd premolar Y=12.09X+3.65 r=0.79 1st molar Y=11.90X+1.25 r=0.78 2nd molar Y=10.51X+10.43 r=0.83 Female 1st premolar Y=13.66X-2.49 r=0.86 2nd premolar Y=13.63X-2.42 r=0.86 1st molar Y=12.42X-1.44 r=0.79 2nd molar Y=11.42X+5.91 r=0.84

• Journal of Periodontal and Implant Science
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• 제38권2호
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• pp.225-230
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• 2008

Purpose: Many clinical studies have reported that higher success rates are achieved with teeth that have immature roots than other autotransplanted teeth that have more immature root. However, based on date published recently, the success rate of autotransplantation of teeth with complete root formation was higher. The purpose of this study was to examine the long term(2 to 6 years follow-up) success rate of autotransplantation of third molar with complete root formation and to discuss some conditions and prerequisites for success. Materials and Methods: 26 sites of 24 patients aged 26 to 55 (mean age 40.8) were autotransplanted with third molars with complete root formation. These cases were followed for 2 to 6 years after surgery. The success criteria included (1) no discomfort during functioning (2) absence of progressive root resorption and alveolar bone resorption. Result: Of 26 teeth 5 teeth were failed, therefore success rate is 81%(21/26 teeth). The results suggested that higher success rate is acquired from (1) extraction socket due to dental caries (2) mandibular recipient site (3) patient younger than 40 years old. Autotransplantation of third molar to replace molars with advanced periodontal disease also showed considerably high success rate(84%). Conclusion: With appropriate case selection, autotransplantation of third molar with complete root formation remains a viable alternative for replacing a missing molar tooth.

• 대한치과교정학회지
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• 제20권2호
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• pp.267-280
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• 1990

The purpose of this study was to investigate the force mechanism of Multiloop Edgewise Arch Wire and the intensity and distribution of stresses with vertical and intermaxillary elastics. The obtained results were as follows. 1. When plain wires were inserted and vertical and intermaxillary elastics were used in the upper and lower arch, the stresses of the anterior and posterior ends of wires were observed greatly but the stresses of the premolar were very small. 2. When MEAW were inserted in upper and lower arch, the upper 1st and 2nd premolar and the lower 1st premolar were extruded greatly. 3. In the area of the upper 1st molar and the lower 2nd premolar and the lower 1st molar, any stresses were not observed. 4. The vertical elastic counteracted the intrusion force of the MEAW in the anterior teeth but could not affect on posterior teeth. Using with the Class II elastics, the distal tipping force and extrusion force were exerted in the upper anterior teeth and the intrusion forces of the lower anterior teeth were relieved. Using with the Class III elastics, the extrusion force were exerted in the upper and lower anterior teeth, the distal tipping force were increased in the lower posterior teeth. 5. The Class II elastic counteracted the anterior intrusion force of the MEAW and extruded and tipped mesially the lower 2nd molar. The intrusion force of the MEAW also could not overcome the extrusion force of the class II elastics. 6. When the Class III elastics were engaged, the upper 2nd molar was extruded in spite of the intrusion forces of the MEAW and the extrusion forces of the lower anterior teeth and distal tipping forces in the posterior teeth were observed.

• 치과방사선
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• 제11권1호
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• pp.51-58
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• 1981

The author examined 515 full mouth roentgenograms stored in the Dept. of Oral Radiology, College of Dentistry, Seoul National University. For evaluating the efficiency of the routine full mouth roentgenogram, each of abnormal conditions such as impacted teeth, missing, caries, crown, filling and apical lesions was observed. The results obtained were as follows; 1. Among 14.420 teeth examined, missing teeth were 174, impacted 16, caries 161 and treated 1,162. 2. The incidence of impacted third molar was close to 18.7 percent and the incidence of missing third molar was about 33.4 percent. 3. Among carious and treated teeth, 178 teeth (1.2%) were needed observation of root apex. And of these teeth, 119 teeth 0.8% were observed with apical lesion. 4. There is a considerable relation between the incidence or size of apical lesion and the accuracy of endodontical treat. 5. Among the teeth with apical lesion, upper and lower first molars were most frequent (about 41%), upper and lower canine were rare (about 1.7%).