• Journal of Periodontal and Implant Science
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• 제31권1호
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• pp.243-258
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• 2001

Gingival recession is exposure of the root surface with apical shift in the position of gingiva. The incidence of gingival recession is 8% in children and 100% after the age of 50. Recession tends to be found in patients with healthy gingiva, but more frequentely found in patients with periodontal disease, and it often causes mucogingival defects. Buccal surface of premolar is the area not only for severe gingival recession and cervical abrasion, but also the area of numbers of buccal frenum and less keratinized gingiva. Threrfore, the goal of this study was to observe the patients with periodontitis and examine whether there are clinical relations between gingival recession and cervical abrasion of premolar and other factors related with the condition of periodontal health. Generally healthy 218 patients who had periodontitis, aged between 18 and 78, were examined for depth of periodontal poket, width of attached gingival, gingival recession, cervical abrasion, and frenum of mid-buccal surface of premolar at the Department of Periodontics in Dankook University Dental Hospital and following is the result. 1. The average gingival recession and cervical abrasion of premolar with periodontal disease was 0.76mm and 0.29mm and each has 43% and 14% of incidence. Also the width of attached gingiva of mid-buccal surface was 1.77mm. the average periodontal pocket depth is 2.0mm and 47% of frequently seen was narrow single shaped frenum, and the interdistance of the frenum was mostly over 4mm. 2. With statistical significance(P<0.05), the incidence of gingival recession increased with age and was related much more with female than male, the first premolar than the second premolar, and with narrow attached gingiva and frenum. 3. With statistical significance(p<0.05), the incidence of cervical abrasion increased with age and was related with the area of the first premolar and narrow attached gingiva, but the sexual and frenum differences were not statistically significant (p>0.05). 4. The severity of gingival recession increased with age and was more related with female than male, the first premolar than the second premolar. And the area of narrow attached gingiva and frenum showed more gingival recession and the distance of frenum was more highly related than shape, and they were statistically significant (p<0.05). 5. With statistical significance(p<0.05), the severity of cervical abrasion increase with age and was observed at the first premolar and narrow attached gingiva. But the sexual and frenum differences were not statistically significant (p>0.05).

• 치과방사선
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• 제20권2호
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• pp.227-234
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• 1990

The purpose of this study was to evaluate the incidence and several radiographic features of dilacerated teeth in 2132 full month radiograms in Korean. The results were as follows: 1. The occurrence was revealed to 2.7% in total examined teeth, and these anomalies were occurred in maxilla (52.4%) more than in mandible (47.6%). 2. There was a predilection for occurrence of dilaceration in female, which included 12.8% of the female compared to 11.3% in male. 3. The frequency of dilaceration in male, which included 40.5% in maxilla and 59.5% in mandible. The frequency of dilaceration in female, which included 52.4% in maxilla and 47.6% in mandible. 4. The order of frequency of dilaceration was second premolar, first premolar, lateral incisor, canine in maxilla, and first premolar, second premolar, canine, lateral incisor, central incisor in mandible. 5. In classifying of dilacerated teeth into 3 types by following appearances such as root curvature. Distal dilaceration was by far most common containing 65.8% of the cases. The least frequent was mesial dilaceration, which included 6.5% of the cases.

• Imaging Science in Dentistry
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• 제40권3호
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• pp.131-135
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• 2010

Purpose : The aim of this study was to investigate the timing and sequence of eruption of permanent canine and premolars, and to evaluate tooth calcification stage on emergence in Korean children. Materials and Methods : The sample was comprised of 1,266 children (male 720, female 546) aged from 7-13 years. Tooth eruption and calcification stages were determined through oral and panoramic radiographic examination, respectively. Probit analysis was used to calculate the timing of tooth eruption and tooth calcification stage from these cross-sectional data. Results : In both males and females, eruption occurred around the time when one third of tooth root or more was formed. The sequence was as follows: first premolar, canine, and second premolar in maxilla, and canine, first premolar and second premolar in mandible. Tooth eruption occurred earlier in girls compared with boys, averaging 0.63 years. Conclusions : Eruption sequence is identical in males and females with a trend for females to erupt earlier than males. Tooth eruption becomes earlier over the past decades in Korean children.

• 대한치과보철학회지
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• 제28권2호
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• pp.77-90
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• 1990

The purpose of this study was to compare the amount of the vertical pin opening of $33^{\circ}$ resin and $0^{\circ}$ resin teeth during processing and to determine whether the changes in tooth contacts by using articulation ribbon and T-Scan system follow any identifiable pattern, and to determine if there is any correlation between the changes in tooth contacts and the amount of the vertical pin opening after processing. Through statistical analyses on the data from this study, the following conclusions were obtained. 1. The amounts of the vertical pin opening were 0.78m, 0.87mm for $0^{\circ}$ teeth and $33^{\circ}$ teeth, respectively. But there was no significant difference between them. 2. The total number of contact points recorded by articulating ribbon after processing was decreased to 442.5% of that before processing. 3. The mean values for the number of contact points per tooth recorded by articulating ribbon after processing were 4.3 for the second molar, 3.8 for the first molar, 1.3 for the second premolar, 0.8 for the first premolar. The reduction of contact points per tooth became greater moving in an anterior direction. 4. The correlation between the reduction of contact points and the amount of the pin opening after processing was not significant. 5. The mean values for the numbers of contact points per tooth recorded by T-Scan system after processing were 2.2, 2.5, 1.0, and 0.5 at the second molar, the first molar, the second premolar, and the first premolar, respectively. 6. The correlation between the number of contact points by using articulating ribbon and TScan system after processing was not significant.

• 대한치과기공학회지
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• 제42권3호
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• pp.220-227
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• 2020

Purpose: This study aims to investigate the cusp variation pattern of the Korean mandibular second premolar and to determine the difference in tooth diameter and surface area using a virtual three-dimensional model. Methods: Dental casts from 69 students were scanned as a virtual dental models with a three-dimensional dental model scanner. Tooth diameter, absolute and relative individual areas, total crown area, the number of lingual cusps and central groove pattern were analyzed using RapidForm 2004. The Mann-Whitney U-test and the Kruskal-Wallis test were performed to verify sexual dimorphism, the difference in tooth diameter and surface according to the cusp variation pattern (α=0.05). Results: There was no significant difference except in buccolingual diameter (p<0.05) and buccolingual diameter at the cervix (p<0.05). The relative surface area of the total clinical crown was 65.76% for the buccal half and 34.24% for the lingual half, with a ratio of 2:1. In the case of the presence of two lingual cusps, the ratio was 21.47% for the mesiolingual half and 14.12% for the distaolingual half, with a ratio of 3:2. The dominant central groove patterns of the second premolar were the H-pattern (42.0%), followed by the Y-pattern (37.7%), then the U-pattern (20.3%). The relative buccal half was largest in the U-pattern central groove and the relative lingual half was largest in the Y-pattern central groove (p<0.05). Conclusion: This study is significant in that it measured quantitative surface areas and the findings could be a meaningful reference to comprehend dental anatomy in Koreans.

• 대한치과의사협회지
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• 제57권11호
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• pp.654-663
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• 2019

This case report describes the management of a 30-year-old woman with hopeless mandibular first molars and right maxillary second premolar. The treatment plan included mandibular second and third molar protraction after extraction of mandibular first molars. Mini-implants were placed between roots of first and second premolar. Sliding mechanics with lever arm was used to prevent inclination of molars. A good functional occlusion was achieved in 38 months without clinically significant side effects. Most of the extraction space of mandibular first molar was closed by protraction of second and third molars. The skeletal Class II pattern was improved by counterclockwise rotation of mandible through reduction of wedge effect. Mandibular molar protraction with orthodontic mini-implants in adequate cases would be a great alternative to prosthetic implant and reduce the financial and surgical burden of patients.

• 대한치과보철학회지
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• 제8권1호
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• pp.30-36
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• 1968

The measurements on the various items, such as arch form, kinds of anterior dental arch, degree of curvature in anterior dental arches, relationship between direction of the disto-incisal edge of the canine and first premolar, and kinds of posterior dental arch in upper dental arches were studied on 311 cases of the Korean adults aged from 20 to 30years. The results were as follows. 1. The commonest type of the upper dental arches was U-type (53.7%), the remaining were O-type (25.4%) and V-type (20.0%). 2. A slight curvature type (71.87%) prevailed against angulated curvature type in upper anterior dental arches. 3. The degree of curvature from $121^{\circ}$ to $160^{\circ}$ in anterior dental arches was common, and the degree of curve of 1-type with on curvature was smaller than 4, 5 type with two curvature. 4. The direction of the disto-incisal edge of canine went between the tip of the buccal cusp and the lingual incline of the buccal cusp of the first premolar in most dental arches and went lingual incline of the buccal cusp of the first premolar in U-type, from buccal cusp to lingual cusp of the first premolar in O-type and were distributed from buccal edge to central groove of the first premolar in V-type. 5. A posterior dental arch with almost straight curvature was common in 60.87%, and 4-type with a half rounded curve from first premolar to second molar was next.

• 대한소아치과학회지
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• 제32권4호
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• pp.693-702
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• 2005

치아의 정확한 맹출 시기와 그 순서는 어린이의 발육 성숙도의 지표로서 소아치과 임상 및 예방 교정치료에 있어서 매우 중요하다. 이에 $2001{\sim}2003$년에 연세대학교 치과대학병원 소아치과에 내원한 어린이 중 만 5세부터 만 14세까지의 남자 654명, 여자 542명, 총 1,196명의 자료를 수집하여 영구치의 맹출 시기 및 순서에 대한 연구 결과 다음과 같은 결론을 얻었다. 1. 상악 영구치의 맹출 시기는 중절치 남 만6.81세, 여 만6.78세, 측절치 남 만8.30세, 여 만7.98세, 견치 남 만10.28세, 여 만10.04세, 제1소구치 남 만9.74세, 여 만9.90세, 제2소구치 남 만10.87세, 여 만10.41세, 제1대구치 남 만6.25세, 여 만6.54세, 제2대구치 남 만12.21세, 여 만12.03세였다. 2. 하악 영구치의 맹출 시기는 중절치 남 만6.00세, 여 만6.06세, 측절치 남 만6.99세, 여 만6.74세, 견치 남 만9.83세 여 만9.17세, 제1소구치 남 만9.92세, 여 만9.75세, 제2소구치 남 만10.66세, 여 만10.39세, 제1대구치 남 만5.99세, 여 만5.75세, 제2대구치 남 만11.92세, 여 만12.17세였다. 3. 영구치의 맹출 순서는 상악에서 제1대구치, 중절치, 측절치, 제1소구치, 견치, 제2소구치, 제2대구치의 순이었고, 하악에서 제 1대구치, 중절치, 측절치, 견치, 제 1소구치, 제2소구치, 제2대구치의 순이었다.

• 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.

• 대한소아치과학회지
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• 제21권2호
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• pp.533-539
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• 1994

The mandibular buccal frenum is a fold of mucous membrane at the posterior labial vestibule, that attaches the lips and the cheeks to the alveolar mucosa, gingiva, and underlying periosteum. The buccal frenum becomes a problem if its attachment is too close to the marginal gingiva. It may then pull on healthy gingiva, encourge plaque formation and interfere with tooth brushing. Heavy buccal frenum mucogingivally results in insufficient attached gingiva, inadequate vestibular depth and high frenum attachment and also difficulty in eruption of mandibular second premolar. Frenectomy in various forms has been used for many years to remove the influence of the frenum. Unfortunately, the results are not always ideal and there is often postoperative relapse because of muscle pull. In this treatment, frenotomy was used in conjuction with autogenous free gingival graft with the object of removing the influence of the buccal frenum and creating an adequate and stable width of attached gingiva. We observed decrease in muscle pull, adequate width of attached gingiva and increased vestibular depth in addition to progressive eruption of second premolar. Periodic follow-up is needed for evaluation of relapse, grafting gingiva and also space regaining for second premolar.