• 대한치과교정학회지
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• 제21권3호
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• pp.657-670
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• 1991

It was said that early rapid palatal expansion was the treatment of choice in case of maxillary constriction with posterior crossbite. The author tried to assess dimensional changes of nasal and oral cavity before rapid palatal expansion and over 4 months of retention by use of three coronal tomograms through the incisal, molar, and maxillary tuberosity areas. The subjects of this study were consisted of 9 boys and 11 girls ranging from 11 to 13 years old. The results were as follows: 1. A mean change in maxillary first molar width was 3.68mm and a mean change in nasal cavity width was 2.26mm after 6.70mm expansion by Hyrax-type screw and over 4 months of retention tomographically in molar cut. 2. A change in nasal cavity width tomographically showed in order of molar cut, incisal cut, maxillary tuberosity cut respectively. 3. There was no correlation between changes in oral cavity width and nasal cavity width.

• 대한치과의사협회지
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• 제12권2호
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• pp.131-134
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• 1974

The author had studied the masticatory effience on three different types; on missing of the first molar, on replacing the missed first molar with crown & bridge and on natural dentition. This study was made from the parched soybeans as testfood by means of mesh technique. As a result of this study on 25 of natural dentitions, 20 of crown & bridges and 25 of missing of the first molars, the following were come out. 1. Masticatory efficiency of natural dentitions was 75.8%, that of crown & bridges was 66.4%, and that of missing of the first molars was 43.7%. 2. Difference of masticatory efficiency of crown & bridges to natural dentitions was 9.4%, that of natural dentitions to missing teeth was 32.1%, and that of crown & bridges to missing teeth was 22.7%.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권5호
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• pp.225-232
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• 2014

Objectives: The purpose of this retrospective study is to find the differentiating characteristics of cystic and cystic-appearing lesions that involve the impacted mandibular third molar by analyzing panoramic radiographs and computed tomography images, and to aid the preoperative diagnosis. Materials and Methods: Eighty-one patients who had a mandibular cystic or cystic-appearing lesion that involved impacted mandibular third molar and underwent cyst enucleation were included in the study. The preoperative panoramic radiograph and computed tomography findings were analyzed in accordance to the histopathologic type. Results: Most of the cystic lesions containing the mandibular third molar were diagnosed as a dentigerous cyst (77.8%). The occurrence of mesio-distal displacement of the third molar was more frequent in the odontogenic keratocyst (71.4%) and in the ameloblastoma (85.7%) than in the dentigerous cyst (19.1%). Downward displacement was primarily observed in each group. Odontogenic keratocyst and ameloblastoma showed more aggressive growth pattern with higher rate of bony discontinuity and cortical bone expansion than in dentigerous cyst. Conclusion: When evaluating mandibular cystic lesions involving the impacted mandibular third molar, dentigerous cyst should first be suspected. However, when the third molar displacement and cortical bone absorption are observed, then odontogenic keratocyst or ameloblastoma should be considered.

• 구강회복응용과학지
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• 제16권2호
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• pp.93-104
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• 2000

Orthodontic treatment in conjunction with second-molar extraction has been a controversial issue among orthodontists over many decades. The aim of this study was to investigate the treatment effects of upper second molar extraction cases. The sample included 19 upper second molar extraction orthodontic cases(ten Angle's Class I's and nine Class II's, average age=13Y 6M) cared at Kyung-Hee University Department of Orthodontics. Lateral cephalometric radiographs were taken before and immediately after treatment. Seventy-nine points were digitized on each cephalogram and 38 cephalometric parameters were computed comprising 22 angular measurements, 13 linear measurements, and 3 facial proportions. The data obtained from each malocclusion group were analyzed by paired t-test. The statistical results disclosed that there was no significant change in skeletal pattern after treatment except for that accountable by growth while there was statistically significant change in dentoalveolar and soft tissue patterns. There were no significant changes in Bjork sum, posterior facial height /anterior facial height and lower anterior facial height /anterior facial height. No significant changes in anteroposterior position of maxilla and palatal plane were manifested. Although facial axis and lower facial height was slightly increased and the mandible was rotated backward and downward, there was no remarkable change in the mandibular plane. There were statistically significant changes in distal movement of upper first molar, molar key correction and overjet reduction while there was no change in the occlusal plane. The upper lip was slightly retracted simultaneously with slight increase in nasolabial angle. These results signify that distalization of upper dentition with the second molar extraction does change occlusal relationship without gross modifications in the craniofacial skeletal configurationson. Henceforth the second molar extracted would be recommended to treat severe anterior crowding and protrusion with minor skeletal discrepancy.

• Restorative Dentistry and Endodontics
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• 제46권2호
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• pp.29.1-29.11
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• 2021

Objectives: This study was conducted to compare the post-fracture survival rate of endodontically treated molar endodontically treated teeth (molar ETT) restored with resin composites or crowns and to identify potential risk factors, using a retrospective cohort design. Materials and Methods: Dental records of molar ETT with crowns or composite restorations (recall period, 2015-2019) were collected based on inclusion and exclusion criteria. The incidence of unrestorable fractures was identified, and molar ETT were classified according to survival. Information on potential risk factors was collected. Survival rates and potential risk factors were analyzed using the Kaplan-Meier log-rank test and Cox regression model. Results: The overall survival rate of molar ETT was 87% (mean recall period, 31.73 ± 17.56 months). The survival rates of molar ETT restored with composites and crowns were 81.6% and 92.7%, reflecting a significant difference (p < 0.05). However, ETT restored with composites showed a 100% survival rate if only 1 surface was lost, which was comparable to the survival rate of ETT with crowns. The survival rates of ETT with composites and crowns were significantly different (97.6% vs. 83.7%) in the short-term (12-24 months), but not in the long-term (> 24 months) (87.8% vs. 79.5%). Conclusions: The survival rate from fracture was higher for molar ETT restored with crowns was higher than for ETT restored with composites, especially in the first 2 years after restoration. Molar ETT with limited tooth structure loss only on the occlusal surface could be successfully restored with composite restorations.

• 한국치위생학회지
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• 제10권1호
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• pp.81-92
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• 2010

Objectives : Thus this study attempted to look into the level of community residents' dental health and the state of their dental diseases and estimate the general dental health condition so that these data can be available as references in upcoming public dental health planning, and to provide fundamental data for promotion of the level of residents' dental health by performing dental health education. Methods : Among community residents who visited the department of Dental Hygiene of Shinsung University for scaling from March to May 2009, the data of total 346 subjects of 129 women and 217 men were selected, and DMFT rate, DMFT index, dental health capacity of the first permanent molar, and tooth morality rate were investigated. For statistical analysis, SPSS 14.0 was used, for general characteristics of the subjects, frequency analysis was conducted, for caries experience in the permanent teeth of the subjects, mean and standard deviation were calculated, for caries experience in the permanent teeth by sex and residence, independent t-test was performed, and for caries experience in the permanent teeth by age, one-way ANOVA was conducted. The significance level applied to these analyses was 0.05. Results : As a result of investigation and analysis on caries in the permanent teeth of community residents who visited the department for scaling in this study, the findings are as follows: 1. For sex, DMFT rate and tooth morality rate were found to be higher in women, while dental health capacity of the first permanent molar was found to be higher in men. 2. For age, DMFT rate and DMFT index were found to be highest in 40~49 years old, while DMFT rate, DMFT index, and tooth morality rate were found to be lowest in under 20 years old. Dental health capacity of the first permanent molar was found to be highest in under 20 years old, 20-29 years old, and 30-39 years old and found to be lowest in more than their sixties as 39.78 points(p<.000). Tooth morality rate was found to be highest in more than their sixties compared to other age groups.(p<.000). 3. For residence, DMFT rate and dental health capacity of the first permanent molar were found to be high in the Metropolitan area, while tooth morality rate was found to be high in Chungcheong area. Conclusions : Seen from the above-mentioned results, great importance shall be attached to the maintenance of residual teeth, and with this, efficient efforts are required to be made for upkeep and promotion of dental health.

• 대한치과교정학회지
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• 제27권5호
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• pp.761-770
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• 1997

연세대학교 치과대학 부속병원 교정과와 영동세브란스 병원 치과 교정과에 내원하여 최근에 교정치료가 끝난 제 I 급 부정교합 환자중 소구치를 발치하고 치료한 발치군과 비발치로 치료한 비발치 치료군 71명을 선정하고 다시 연령에 따라 청소년기와 성인으로 분류하여 교정치료 전후의 두부방사선 계측분석 사진을 통하여 치아와 연조직의 수평$\cdot$수직적 변화를 비교분석하여 다음과 같은 결론을 얻었다. 1. 발치군과 비발치군간의 비교에서는 SN-MP angle, E-line에 대한 상순의 이동, 상악 제1대구치의 수직이동량, 하악 제1대구치의 수평이동량 등의 항목을 제외한 모든 치아계측항목과 연조직 계측항목에서 유의차를 나타내었다. 2. 청소년기의 발치군과 비발치군간의 비교에서는 상하악 전치의 경사도와 수직기준선으로부터의 전치부 수평 변화 항목, 상악 제1대구치의 근심이동, E-line에 대한 상,하순의 위치변화에서 유의차를 나타내었다. 3. 성인에서의 발치와 비발치군간의 비교에서는 상하악 전치의 경사도와 수직기준선으로부터의 수평적 위치 변화와, 상악 제1대구치의 수직 고경 및 하악 제1대구치의 근심이동, E-line과 수직기준선으로부터의 상,하순의 위치 변화에서 유의차를 나타내었다. 4. 청소년기와 성인 모두에서 SN-MP angle의 변화는 발치군과 비발치군간에 유의차가 없었다.

• 대한치과교정학회지
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• 제23권4호
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• pp.633-644
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• 1993

There has been so much controversies about the position of upper and lower jaws, and their first permanent molars in normal occlusion and Angle's class $I{\cdot}II{\cdot}III$ malocclusions. So, the purpose of this study is to compare the position of upper and lower jaws, and their first molars in normal occlusion and Angle's class $I{\cdot}II{\cdot}III$ malocclusions by lateral cephalometric analysis. The sample consisted of one hundred and twenty girls(thirty in each group) who had completed growth. The findings of this study were as follows : 1. In class I malocclusion, both maxilla and mandible were slightly posterior position than normal occlusion, but they showed harmonious relationship. 2. In class II malocclusion, the mandible was greatly retruded, and the maxilla was also slightly retruded to the cranial base as compared with normal occlusion. 3. In class III malocclusion, the maxilla was significantly retruded to the cranial base, but no significant difference was found in mandibular position as compared with normal occlusion. 4. The maxillary first molar was located at posterior position in class II malocclusion, and anterior position in class III malocclusion to the cranium, so that the rotation of mandible was influenced by that. 5. The mandibular first molar showed constant relationship to the mandible in all four groups, but different position to the cranial base in direct proportion to the mandibular position. 6. On the treatment planning of class III malocclusion, it seems to be better to promote the mandibular horizontal growth by inhibiting the vertical growth of maxillary molar area, and on the treatment planning of class III malocclusion, it seems to be better to promote the antero-inferior growth of maxilla mi to promote the mandibular vertical growth by inducing the vertical growth of maxillary molar area.

• 대한소아치과학회지
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• 제34권2호
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• pp.322-328
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• 2007

제1대구치는 저작과 혼합치열기 이후의 수직적 교합관계형성에 핵심적인 역할을 하고 악골의 성장발육에 관여한다. 제1대구치의 매복은 하안면 고경의 감소, 낭의 형성, 치관 주위염, 인접치의 치근 흡수, 부정 교합 등의 문제점을 야기할 수 있다. 치료방법으로는 주기적 관찰, 외과적 노출술, 교정적 견인, 외과적 재위치술, 발치 등이 있으며 이중 외과적 노출술이 가장 기본이 되는 술식이다. 외과적 노출술시에는 맹출로의 개방성을 유지하는 것이 중요하며 개방성을 유지시키기 위한 방법으로는 레진관의 접착, 산화 아연 유지놀 시멘트, 치주포대 등을 노출된 부위에 충전시키는 방법 등이 있다. 본 증례에서는 매복된 하악 제1대구치에서 장애물의 제거와 외과적 노출술을 시행한 결과 자발적인 맹출을 관찰할 수 있었다. 또한 surgical pack과 투명상유지장치를 사용하여 간편하고 효과적으로 맹출로의 개방성을 유지할 수 있었다.

• 대한소아치과학회지
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• 제46권1호
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• pp.10-20
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• 2019

개인의 치령은 연령 추정의 한 지표로 사용되고 있으며, 아동의 성장 단계를 알 수 있는 중요한 지표가 된다. 치령의 변화는 시대의 변화에 따라 크지는 않지만, 꾸준히 변하게 되며 이에 대한 정보의 업데이트의 중요성은 널리 알려져 있다. 이에 이 연구는 진단 모형을 이용해 한국 아동의 치아 맹출 단계에 대한 정보를 제공하고, 이 정보를 바탕으로 치아 맹출 순서를 조사하고 연령 추정을 시행해 보았다. 5 - 13세 아동 488명의 진단 모형을 통해 치아 맹출 단계에 대해 조사하였다. 맹출 단계 정보를 바탕으로 한 영구치의 맹출 순서는 남녀 모두 상악에서는 제1대구치, 중절치, 측절치, 제1소구치, 견치, 제2소구치였으며, 하악에서는 제1대구치, 중절치, 측절치, 견치, 제1소구치, 제2소구치, 제2대구치 순서로 나타났다. 일부 나이에서 견치, 제1,2소구치, 제2대구치에서 남녀 간의 유의한 맹출 단계 수준의 차이를 보였다. 연령별 맹출 단계를 바탕으로 선형회귀분석을 이용해 연령 추정을 시행해 본 결과 남아와 여아의 나이를 결정 계수 0.816와 0.826 수준으로 추정해 볼 수 있었다.