• The Journal of Korean Academy of Prosthodontics
• /
• v.46 no.2
• /
• pp.185-192
• /
• 2008

Purpose: This study was designed to investigate the fitness of adjustable dental impression trays on the Caucasian and African American. Material and methods: The size and shape of these trays were designed from the results of the dental arch size of Korean adults. Tray samples were made by CAD-CAM working. Sixty Caucasian (male:30, female:30) and sixty African American (male:30, female:30) were selected for taking irreversible hydrocolloid impression using these trays. The author measured the width and length of impression material on the several measuring points. Results: 1. Uniform impression material width was achieved by controling the width of the tray using stops and beveled guides. 2. In the maxillary tray on the Caucasian, the impression material thickness was measured to be rather great showing thickness of the midpalatal part 13.0 mm. 3. In the maxillary tray on the African American, the impression material thickness was measured to be rather great showing thickness of the midpalatal part 12.0 mm, posterior palatal part 11.0 mm and the labial frenum width was 11.0 mm. 4. In the maxillary tray on the African American, the impression material width of posterior border (0.8 mm) was measured to be small. 5. In the mandibular tray on the Caucasian, the impression material width was measured (2.7-6.7 mm) and posterior border width (2.1 mm) was measured small. The impression material length was measured (2.8-6.7 mm). 6. In the mandibular tray on the African American, the impression material width was measured to be rather great showing width of the labial frenum 9.2 mm and the width of posterior border was measured too small (0.3 mm). Conclusion: This adjustable dental tray shows good accuracy to Korean because it was designed by the analysis of the dental arch size of Korean adult model. With this result, it can be applied to Caucasian and African American, we can take more easy and accurate dental impressions.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.31 no.6
• /
• pp.505-509
• /
• 2009

Purpose: To evaluate the properties of antibiotic and NSAIDs administration before extract of the impacted mandibular third molar. Materials & Methods: No patient showed any sign of pain, inflammation, or swelling at the time of removal. A group of 50 patients was classified in Group 1(preemptive and oral medication was carried out for 3 days postoperatively, N=23) and Group 2(oral medication was carried out for 3 days postoperatively, N=27) subgroups. Clinical and radiologic factors were recorded for each case, and the rationale for assigning the patients to the groups was strictly random. The surgical technique was the same in all cases, and the follow-up period was 1 week. Parameters that were evaluated were infection, swelling, pain and differences in mouth opening. Results: We could not find any significant difference between the 2 groups regarding the evaluated parameters. Conclusion: The results of our study show that antibiotic and NSAIDs administration before the removal of lower third molars does not contribute to a decrease infection, swelling, pain or increase mouth opening. Therefore antibiotic and NSAIDs administration before the removal of lower third molars is not recommended for routine use.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.26 no.1
• /
• pp.1-12
• /
• 2010

The purpose of this study was to compare the strain on the alveolar ridge in the centric, eccentric and protrusive position according to the occlusal scheme (bilateral balanced occlusion with 33 degree anatomical teeth, group B; monoplane occlusion with non-anatomical teeth, group M; lingualized occlusion with 33 degree anatomical teeth and non-anatomical teeth, group L; of complete dentures. Experimental dentures were set bilateral balanced occlusion, lingualized occlusion and monoplane occlusion. They are analysed through T-Scan II(Tekscan, Boston, U.S.A) and 1.5mm thick layer was removed from the denture-supporting surface of resin model and then replaced with silicone to simulate resilient edentulous ridge mucosa. A $4{\times}6$ linear strain gauge is attached to the $1^{st}$ premolar and $1^{st}$ molar area. The strain values are recorded according to the occlusal scheme in the centric, eccentric and protrusive position after uniformly applying 50 N and 150 N force through a Universal Testing Machine(instron$^{(R)}$ 5567, Bluehill 2.0 software ,U.S.A.) with the models mounted in the articulator. When performing centric and protrusive occlusion, the three groups of occlusal scheme were compared in the anterior region and in the posterior region. The strains of each group were also compared in the working side and in the non-working side during eccentric excursion. It was observed that the strain in the bilateral balanced occlusion showed a higher value than the lingualized occlusion and monoplane occlusion in every position except the non-working side. However, during the eccentric movement the strain value in the non-working side showed the lowest value in the bilaterally balanced occlusion. The strain change amount from the working side or centric occlusion to non-working side and also the strain variation rate within the non-working side showed the highest value in bilateral balanced occlusion.

• The korean journal of orthodontics
• /
• v.38 no.2
• /
• pp.95-103
• /
• 2008

Objective: This study was performed to investigate the labio/buccal clinical crown curvatures of Korean permanent teeth and to obtain the curve-ratio data in an attempt to fabricate bracket bases fit for each individual Korean permanent tooth. Methods: Three-dimensional digital models were made from 30 sets of dental casts with normal anatomic structures. According to the FA points, horizontal and vertical reference planes were established and lines were drawn on the tooth surfaces in reference to these planes. The curvature was expressed as the coefficient of a quadratic equation. Lines mesial, distal, gingival and occlusal to the horizontal, vertical reference planes and the FA point were drawn. Results: The curvature measured for each line revealed that there are no significant differences between male and female, except for maxillary canines and maxillary second bicuspids (p > 0.05). There were notable differences in the mesio-distal or gingivo-occlusal curvatures among the mandibular lateral incisors, maxillary canines, maxillary and mandibular first and second bicuspids and first molars (p < 0.05). Conclusions: The labial & buccal crown curvatures of teeth in Korean normal occlusion were measured on the mesial and distal, gingival and occlusal sides respectively in this study. Based on these data, a SWA can be developed to fit the individual features of Korean tooth crowns.

• The korean journal of orthodontics
• /
• v.34 no.1 s.102
• /
• pp.1-11
• /
• 2004

Predicting the arch length discrepancy by simply comparing the available arch perimeter with tooth materials is merely a 2-dimensional analysis of the teeth movement. However, the real teeth movement takes place 3-dimensionally and is affected by various factors such as, the arch fen the curve of Spee and the axis of the incisors. The purpose of this study is to clarify the relationship between the decrease in the arch perimeter and the horizontal positional change of the incisors after extraction of the 1st bicuspids, for more analytic evaluation of the arch length discrepancy at pre-treatment model analysis stage. In addition to that to evaluate the effect of the curve of Spee, teeth axis to the basal plane, and the incisional crowding to the treatment outcome. All patients were treated at the department of orthodontics, dental hospital, Yonsei university. Inclusion criteria for patients selection were as follows. $\cdot$ Angle classification I malocclusion with bialveolar protrusion $\cdot$ Extraction of 4 1st bicuspids $\cdot$ No tooth anomaly or prosthesis $\cdot$ No abnormal attrition $\cdot$ No ectopically erupted teeth $\cdot$ Angle classification I canine and molar relationship $\cdot$ Less than 3mm of crowding Model analysis of the above patients was performed and the following conclusions were obtained. 1. When the intercanine distance was maintained, the available space for the distal movement of the mandibular incisors after the extraction of the 4 1st bicuspids was larger than the space provided by the extraction of the 4 1st bicuspids. However the difference was less than 1mm. The more tapered the anterior arch form, the larger the difference. 2. Compared to the situation in which the intercanine distance was maintained, when the intercanine distance was expanded to meet the width of the Posterior teeth, the incisors could move about 3mm more distally. 3. The positional difference of the incisal tip was insignificant whether the central incisors were moved by tipping or bodily movement. 4. When the anterior crowding was solved without changing the intercanine distance, the larger the anterior arch length was, the more the anterior movement of the incisors. 5. When the curve of Spee was levelled, the increase in the arch perimeter was less than half of the deepest curve of Spee.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.34 no.2
• /
• pp.309-314
• /
• 2007

Ameloblastic fibroma is a rare benign tumor, accounting for only 2.5% of odontogenic tumors. It occurs during the period of tooth formation between the ages of 5 and 20 years with the average age being about 15. There is no gender predilection. In the majority of cases, the lesion arises in the mandible, presenting the swelling of jaw and the failure of tooth eruption. In this report, the main concern of the patient was the failure of eruption of lower permanent and deciduous molars. Radiographic investigation showed a radiolucency surrounding the crown of unerupted teeth. Surgical intervention and histopathologic study revealed the lesion to be ameloblastic fibroma. After the surgery, no evidence of residual tumor or recurrency was found. These patients are scheduled for the long-term continuing evaluation of the eruption of adjacent teeth and successor with radiographic study.

• Journal of agricultural medicine and community health
• /
• v.45 no.2
• /
• pp.79-88
• /
• 2020

연구목적: 이 연구는 지역사회 치면열구전색 사업의 치아우식 예방효과를 평가하고자 시행되었다. 연구방법: 연구 대상자는 2005년부터 2008년까지 김천시에 소재한 34개 초등학교에 재학 중인 9,001명 중 2005년 최초 구강검사 당시 상·하악 제1대구치에 치아우식이 없는 치아와 학생 4,768명을 최종 대상자로 선정하였다. 2005년도에 치면열구전색을 실시한 1,478명에 대해 3년간 추적조사가 이루어졌고, 2006년에 치면열구전색을 실시한 999명에 대해 2년간 추적조사를 하였으며, 2007년에 치면열구전색을 실시한 458명에 대해 1년간 추적조사 후 기술통계 및 교차분석을 시행하였다. 연구결과: 치면열구전색 실시군의 DMFT rate는 1년 추적 후 1.4%에서 3년 추적 후 4.1%, DMFT index는 1년 추적 후 0.18개에서 3년 추적 후 0.70개로 추적기간이 길어질수록 높게 나타났다. 1일 평균 칫솔질 횟수는 DMFT rate와 DMFT index에 영향을 미쳤다. 즉 치면열구전색을 실시한 대상자라도 1일 평균 칫솔질 횟수가 적으면 DMFT rate와 DMFT index는 높게 나타났다. 결론: 치면열구전색을 실시한 대상자에서도 올바른 칫솔질에 대한 구강보건교육이 선행되어야 한다.

• The Journal of the Korean dental association
• /
• v.55 no.5
• /
• pp.328-338
• /
• 2017

Introduction: The aim of the current study was to describe the prevalence and treatment of mandibular first molar eruption disturbances. Methods: A total of 38 mandibular first molars(M1mn) from 36 patients(17 males and 19 females; aged 9 years 2 months?35 years 10 months) were identified from the 13,391 patients that received orthodontic treatment from 1983?2012. The subjects were classified into 3 categories based on panoramic radiographic examination: impaction due to ectopic position of the tooth germ relative to the contra-side same tooth(Group 1), impaction due to obstruction of the eruption path with cyst or calcium mass (Group 2), and primary and secondary retention due to defects in the follicle or periodontal ligament(PDL; Group 3). The treatment outcomes were evaluated into four categories: no treatment(A), orthodontic traction(B), autotransplantation(C), and extraction due to orthodontic traction failure(D). Results: The prevalence rate of M1mn eruption disturbances in this sample was 0.27%. In Groups 1 and 2, most of the impacted M1mn were erupted successfully by orthodontic traction. In Group 3, most of the retained M1mn were failed to erupt and recommended for extraction. Conclusions: Treatment prognosis was favorable on Group 1 & 2 than Group 3. After removing an element of the cause in case of Group 1 & 2, orthodontic traction or periodic observation will be recommended.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.36 no.2
• /
• pp.270-274
• /
• 2009

Dentigerous cysts generally encompass the crown of an unerupted tooth. These cysts are usually solitary. They are the second most common odontogenic type of cysts following radicular cysts, and are frequently associated with impacted mandibular third molars or maxillary canines. Most multiple cysts found in the jaw are odontogenic keratocysts associated with the nevoid basal cell carcinoma syndrome, mucopolysaccharidoses and cleidocranial dysplasia. Although a single dentigerous cyst is well documented in the medical literature, including the prevalence, treatment and prognosis, multiple dentigerous cysts without any systemic symptoms is unusual. Furthermore, cases involving both the maxilla and mandible are especially rare. We present the case of an 11-year-old boy with nonsyndromic multiple dentigerous cysts associated with a mandibular second premolar and a maxillary canine. The treatment was conservative and included marsupialization and eruption guidance. Further follow up is planned to rule out additional problems and the possible identification of a syndrome.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.38 no.4
• /
• pp.233-241
• /
• 2022

Purpose: The purpose of this study was to assess the dimensional change of 3D-printed dentures after post-curing. Materials and Methods: The upper and lower dentures were designed in Exocad DentalCAD software and exported as STL files. The upper and lower dentures were printed from 10 STL files using a DLP-type dental 3D printer. The printed upper and lower dentures were cleaned, and a scan file was created using a model scanner before and after post-curing. The dimensional change was evaluated by superimposing the scanned denture files before and after post-curing and measuring the distance between measurement points on the denture. SPSS was used for statistics, and the level of significance was 5%. Results: The maxillary denture reduced in size during post-curing, with the most notable color change occurring in the posterior palatal region. The reduction in anteroposterior maxillary denture length (A-D, A-E, A-F), as well as the distance between the first molars on both sides (B-C), was statistically significant. After post-curing, the mandibular denture showed more noticeable color change in the posteriorly buccal and lingual region. The decrease of length on the posterior (A-M, A-D, A-E, A-L, A-H, A-I, H-I) and lingual (J-K, L-M) sides of the denture were statistically significant. Conclusion: There was significant dimensional change in both the length and width of the 3D-printed maxillary and mandibular dentures after post-curing in this experiment. Consequently, it is seemed necessary to develop post-curing techniques and materials that reduce such denture deformation.