• 대한치과교정학회지
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• 제52권1호
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• pp.42-52
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• 2022

Objective: This study compared soft tissue changes after extraction of the four premolars followed by maximum retraction of the anterior teeth according to the type of anterior teeth movement: tipping and translation. Methods: Patients who had undergone orthodontic treatment involving the extraction of four premolars were retrospectively selected and divided into either the tipping (n = 27) or translation (n = 26) groups based on the retraction of the incisor root apex and the axis changes of the incisors during the treatment period. Lateral pre- and post-treatment cephalograms were analyzed. Results: There were no significant differences between the tipping and translation groups before treatment. The retraction amounts of the root apex of the upper and lower incisors in the tipping group were 0.33 and 0.26 mm, respectively, and 5.02 and 5.31 mm, respectively, in the translation group (p < 0.001). The posterior movements of soft tissue points A and B in the tipping group were 0.61 and 1.25 mm, respectively, and 1.10 and 3.25 mm, respectively, in the translation group (p < 0.01). The mentolabial sulcus angle increased by 5.89° in the tipping group, whereas it decreased by 8.13° in the translation group (p < 0.001). Conclusions: An increased amount of retraction of the incisor root apex led to the increased posterior movement of soft tissue points A and B, and this appeared more distinct in cases involving the lower incisor and lower lip.

• 대한치과기공학회지
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• 제25권1호
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• pp.95-102
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• 2003

The purpose of this study was to show occlusion on the simple hinge articulator optionally mounted. Modelling of upper-lower jaw and simple hinge articulator were developed. This modelling of upper-lower jaw inserting wax bite was mounted imaginary on the modelling of simple hinge articulator by use of the computer simulation. From changes of THA(transverse horizontal axis)-incisor distance, Balkwill angle and THA deviation, eight types were mounted respectively. After removal of wax bite, upper-lower jaw position changing were compared with centric jaw relation. The results were as follows: 1. The change of THA-incisor distance had influence on mostly a vertical shift of upper jaw. 2. The change of Balkwill angle had influence on mostly a horizontal shift of upper jaw. 3. Inferior type in the THA deviations was the least shift of upper jaw. The above results suggest that the simple hinge articulator optionally mounted effect a shift of upper jaw.

• 구강회복응용과학지
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• 제30권3호
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• pp.223-230
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• 2014

목적: 하악 절치 발치 치료를 받은 환자들의 치료로 인한 향상과 유지기간 후의 안정성을 평가하는 것이다. 연구 재료 및 방법: 하악 절치를 발치한 환자 총 20명을 대상으로 치료 전, 치료 직후, 2년의 유지기간 후의 모형 및 파노라마 방사선 사진을 분석하였다. Irregularity index, overjet, overbite, 치아 크기와 악궁 길이의 차이, 견치간 폭경, 제1 대구치간 폭경 및 미국교정학회에서 제시한 방법(ABO-CRE)을 평가하였다. 통계분석은 Wilcoxon signed-rank test를 이용하였다. 결과: 치료 전후 irregularity index가 유의하게 감소되었고(P = 0.000), 치아 크기와 악궁 길이의 차이는 유의하게 증가 하였다(P = 0.028). 유지기간 동안에 irregularity index는 유의하게 악화 되었다(P = 0.001). ABO-CRE 전체값의 변화는 치료 전후에 유의한 감소를 보이고(P = 0.000), 유지 전후에는 유의한 차이를 보이지 않았다(P = 0.053). 결론: 모형과 파노라마 방사선 사진을 이용하여 치료의 안정성 평가 결과, 하악 절치 발치 치료는 2년간의 유지기간 동안 치료 결과가 안정적으로 유지되었다고 할 수 있다.

• 한국치위생학회지
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• 제12권2호
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• pp.345-353
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• 2012

Objectives : The author has studied about correlation of gingival exposure upon smiling and oral facial status that reduce facial aesthetic. Methods : The subjects in this study are 91 female vulunteers who were in aged $21.4{\pm}1.89$ in Suwon. Objectives should be normal oral and facial status without the prosthodontic, orthodontic appliance or conqenital missing tooth, and agree to be examined the oral status and impression taking. 1.Measure the length of gingival exposure upon smiling. 2.Measure of the size on central incisor. 3.Measure of Facial. SPSS(SPSS 10.0 for windows, SPSS Inc, Chicago, USA) was utilized for calculating the correlation coefficient between gingival exposure upon smiling and facial status. Regression analysis was calculated in order to predict the R square for gingival exposure upon smiling. Results : 1.Correlation coefficient between the gingival exposure and length of maxillary central incisor was calculated as reversed correlation(r=-.302, p<0.01), and between the gingival exposure and the ratio of the length of central incisor/width of central incisor was revealed as reversed correlation(r=-.250, p<0.05) on smiling. 2.There was correlation between the gingival exposure and the facial height(r=.351, p<0.01), the lower facial height(r=.454, p<0.01) and the upper lip height(r=.274, p<0.01) upon smiling. 3.There was correlation between the gingival exposure and the ratio of the facial height/facial width(r=.358, p<0.05), the ratio of the upper facial height/facial width(r=.214, p<0.05), and the ratio of the lower facial height/facial height(r=.383, p<0.01) upon smiling. 4.The equation of the regression analysis for gingival exposure upon smiling could be estimated as gingival exposure upon smiling=-5.139+.279${\times}$lower facial height-.615${\times}$maxillary central incisal length-.05${\times}$nasolabial angle. Conclusions : Considering these results, it recommended that treatment planning should be designed in consideration of such factors as the length of maxillary central incisor, facial height, upper lip height and lower facial height, in order to promote the easthetic problems of face on smiling.

• 대한치과보철학회지
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• 제45권1호
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• pp.1-11
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• 2007

Statement of problems: The concept of CR has also changed continuously.?In order to find out the factors that affect the centric slide, studies were carried out to compare the forms of wisdom teeth eruption, lateral movement, premature contact in CR, and anterior movement. Research and statistical methods were based on the report by the 1980 Korean dental association. Material and method: In our study, 403 dentists in their twenties and dentistry students who could understand CR and CO (and who did not receive occlusal, orthodontic treatment, without extreme caries and large prosthodontic care) were compared with the 25 year old results. A segment of line parallel to the upper incisor was marked on the lower incisor. When seen laterally, a line perpendicular to the occlusal plane was drawn on the foremost area of the upper incisor. This line was extended to the lower incisor and the two points (points at the lower and upper incisors) were used as reference points for the CO. After guiding the occlusion to the CR, two lines were marked by using the same method that was used for the CO. The point in which these lines meet became the reference point of CR occlusion Results and conclusions: Results of the experiment completed in 1980 show that all 307 research members had anterior-posterior and upper-lower displacement. Displacement measurements were $0.7{\pm}0.4mm$ for the anterior-posterior displacement, $0.99{\pm}0.50mm$ for the upper-lower displacement,0.18{\pm}0.31 mm for the lateral displacement, and $1.32{\pm}0.67mm$ for the total displacement. Results of the 2006 experiment show that all 409 research members had anterior-posterior and upper-lower displacement. The anterior-posterior displacement was $1.12{\pm}0.86mm$, the upper-lower displacement was $1.02{\pm}0.71mm$, the lateral displacement was $0.61{\pm}0.56mm$, and the total displacement was $1.80{\pm}0.99mm$. No specific differences were found between each group when comparing displacement according to the forms of wisdom teeth eruption. Since 1980, the percentage of unerupted teeth has increased from 35.16% (111/307 people) to 57.5% (236/409 people). Westernization of the Korean cranial form and intraoral structure has brought about these results. In our experiment, 26.7% (109/409 people) of the subjects were cuspid guided, while 7.3% (30/409 people) were mutually guided. No specific differences were found in the amount of displacement between the two groups. Only the subjects with anteriors coming in contact made up the largest percentage group (42.3%, 173/409 people) in our study. No specific differences were found between each group.

• 대한치과교정학회지
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• 제28권1호
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• pp.135-142
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• 1998

치아돌출정도가 부착치은 폭경에 미치는 영향을 살펴보기 위하여 치주상태가 양호한 성인 중 하악 전치부에 다소의 총생이 있는 37명을 대상으로 하악의 인상채득 후 석고모형을 제작한 다음 각 하악 절치의 상대적 및 절대적 돌출정도를 측정하고 임상치관 고경, 치주낭 깊이, 각화 및 부착치은 폭경과 비교 분석하여 다음과 같은 결론을 얻었다. 1. 비돌출측에 비하여 돌출측의 각화치은 및 부착치은 폭경이 작게 나타났다. 2. 돌출측의 임상치관 고경은 비돌출측보다 유의하게 크게 나타났으나 치주낭 깊이는 돌출측과 비돌출측간의 유의한 차이를 보이지 않았다. 3. 돌출측과 비돌출측간의 부착치은 폭경차이는 중절치보다 측절치에서 더욱 뚜렷이 나타났다. 4. 절대적 돌출도보다 상대적 돌출도가 부착치은 폭경과 더 높은 상관관계를 나타내었다. 5. 돌출도보다 임상치관고경이 부착치은 폭경과 더 높은 상관관계를 나타내었다.

• Journal of Oral Medicine and Pain
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• 제4권1호
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• pp.22-30
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• 1979

In order to evaluate the normal eruption time of Korean permanent teeth, the uthor had examined the eruption phases of permanent central incisors in 714 malw and 581 female children aged from 4.5 to 9-year old and analysed. The eruption was divided into 3 phases; the tip of crown can be seen, the half of the crown can be easily seen, and full length of the crown can be seen. The obtained results were as follows : 1. It seemed that percentage of the erupting and erupted permanent central incisor in female by age was higher than that of male. 2. In general, percentage of the erupting and erupted lower central incisor by age was higher than that of upper first molar.

• 대한치과보철학회지
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• 제22권1호
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• pp.79-84
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• 1984

The stability of teeth is an important measure of the periodontal health. This study was designed to determine if there was a relation between the patterns of disclusion and a tooth mobility. An evaluation was made on 117 persons with Angle's class I occlusion who were free from histories of orthodontics, removable or fixed prosthesis, and anterior crowding or open contacts. The results were as follows: 1. In this study, 17.52% of the subjects were exhibited canine protected occlusion. 2. In protrusive movements, 75.21% of the subjects were exhibited incisor guided occlusion and the subjects of canine guided occlusion was the smallest. 3. The canine tooth of mouths having canine-protected occlusions had slightly lower mean tooth mobility scores than the canine of mouths having group function occlsion, but there was no significances. 4. The tooth mobility score of central incisor had higher than that of lateral incisor.

• The Journal of Advanced Prosthodontics
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• 제12권6호
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• pp.338-343
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• 2020

PURPOSE. The present study aimed to investigate the relationships between the crown form of the upper central incisor and their labial inclination, overbite, and overjet. MATERIALS AND METHODS. Maxillary and mandibular casts of 169 healthy dentitions were subjected to 3D dental scanning, and analyzed using CAD software. The crown forms were divided into tapered, square, and ovoid based on the mesiodistal dimensions at 20% of the crown height to that at 40%. The degree of labial inclination of the upper central incisor was defined as the angle between the occlusal plane and the line connecting the incisal edge and tooth cervix. The incisal edges of the right upper and lower central incisor that in contact with lines parallel to the occlusal plane were used to determine the overbite and overjet. One-way ANOVA was performed to compare the labial inclination, overbite, and overjet among the crown forms. RESULTS. The crown forms were classified into three types; crown forms with a 20%/40% dimension ratio of 1.00±0.01 were defined as square, >1.01 as tapered, and <0.99 as ovoid. The labial inclination degree was the greatest in tapered and the least in square. Both overbite and overjet in tapered and ovoid were higher than those in square. CONCLUSION. Upper central incisor crown forms were related to their labial inclination, overbite, and overjet. It was suggested that the labial inclination, overbite, and overjet should be taken into consideration for the prosthetic treatment or restoring the front teeth crowns.

• 대한치과교정학회지
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• 제6권1호
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• pp.55-63
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• 1976

This study was undertaken to establish the roentgenocephalometric standards of the Korean children in Hellman dental age III C. The subjects consisted of 33 males and 33 females with the normal occlusion and acceptable profile. The lateral cephalometric films were taken with the teeth in centric occlusion, the soft tissue outline of the nose, lips, and chin was made visible by the low-speed films, 70Kvp, 100Mas. Their linear and angular measurements were performed by Jarabak's methods. The following results were obtained; 1) The author made the tables of standard deviation from the measured values. 2) Each linear measurement of the skull was greater in males than in females. 3) The maxillary basal bones were more protrusive in Korean children than in Caucasian. 4) The degree of the facial convexity was larger in Korean children than in Caucasian. 5) The labial inclination of the upper & lower incisors was greater in Korean children than in Caucasian. The labial inclination of the upper incisor was greater in females, but the labial inclination of the lower incisor was greater in males.