• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.1
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• pp.32-44
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• 2023

Purpose: The purpose of this study was to investigate the effect of implant connection type on marginal bone loss (MBL) and to analyze the factors that affect MBL. This study focuses on single implants planted in the upper and lower first molar area. Materials and Methods: A total of 87 implants from 68 patients were tracked for a period over 5 years. There were 57 external connection type (EC) implants and 30 internal connection type (IC) implants in 38 males and 30 females. The MBL and EA were measured from intraoral radiograph images taken after 5 years at most. Results: Significant difference in MBL between EC and IC type was observed in patients without GBR or diabetes. Patients without GBR exhibited an MBL of -0.065 ± 0.859 mm in EC type and -0.627 ± 0.639 mm in IC type (P = 0.025). Using multiple regression analysis, a statistically significant negative correlation was observed between MBL and conditions including implant-abutment connection type (β = -0.303), diabetes (β = -0.113), emergence angle > 30° (β = -0.234), and age (β = -0.776). Conclusion: Within this results, IC type implants had less MBL than EC type, and implant prosthesis with emergence angle over 30° showed greater MBL. To minimize the MBL of the implant and ensure implant stability, careful consideration should be given to the EA of implant prosthesis and its connection type.

• Journal of Oral Medicine and Pain
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• v.32 no.4
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• pp.375-381
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• 2007

Occlusal stabilization appliance is one of the most common treatment option for management of temporomandibular disorders. It acts in oral cavity for several hours per day, and usually it will take at least 6 months to 2 years of total wearing periods to take a treatment goal. In the oral cavity, occlusal stabilization appliance, unintentional manner, is able to acts as a reservoir of bacteria and protect bacteria from saliva and oxygen. This condition is so favorable to many bacteria such as S. mutans and other anaerobes, usually have been reported as causative factors of dental caries, periodontal disease and oral malodor. In this study, we investigated anaerobic bacteria and S. mutans count before and after occlusal stabilization appliance use to evaluate the possible role of occlusal stabilization appliance as protector of these bacteria. Four men(average 27.5 years) wore maxillary occlusal stabilization appliance at each night(average 9 hours) for 5 days. we swabbed saliva-plaque mixed sample at 3 different site(maxillary left 2nd molar, maxillary left central incisor, mandibular left 2nd molar) before and after occlusal stabilization appliance use. Each samples were plated in (1) anaerobic blood agar medium, (2) selective S. mutans medium(MS-MUTV) and incubated in anaerobic chamber($CO^2$ 10%, $37^{\circ}C$) for 72 hours. Each bacterial colony forming unit(CFU) were counted with naked eyes. From obtained data, we can conclude as follows: 1. There was some changes about anaerobic bacteria and S. mutans count in oral cavity after occlusal stabilization appliance use. 2. The number of anaerobic bacteria was significantly increased at maxillary 2nd molar(P=0.003), maxillary central incisor(P=0.020) after occlusal stabilization appliance use compared with before. 3. Occlusal stabilization appliance use itself had indirect effect to increase the number of anaerobic bacteria at other uncovered opponent tooth site. 4. The number of S. mutans was significantly increased at maxillary 2nd molar(P=0.043), maxillary central incisor (P=0.049) after occlusal stabilization appliance use compared with before. 5. Occlusal stabilization appliance use itself had not any effect on the number of S. mutans at other uncovered opponent tooth site.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.2
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• pp.185-189
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• 2011

Tooth impaction represents the stop of eruption by clinical and radiographical disturbance in eruption path or the dislocation of tooth germ. The most common factor in tooth eruption disorders are spacial deficiency with other causes reported to be odontogenic tumors, periodontal ligament injury, etc. Impaction of the mandibular second molar is relatively rare and reported in about 3 out of 1,000 people. Because the second molars tend to erupt in a mesial direction, this situation can lead to serious problems if untreated, including dental caries, periodontal disease and root resorption of the first molar. Treatment of this problem includes, surgical repositioning and orthodontic forced eruption. Because each procedure have the definite advantages and disadvantages, and influenced by circumferential environment, these have limits for successfu1 recovery as independent treatment. In a case at St. Mary's Hospital, we performed successful correction of a horizontal impacted mandibular second molar using a miniplate skeletal anchorage system. We introduce this treatment as a valid method for an impacted second molar and consider a oromaxillofacial surgeon's role in tooth movement treatment.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.262-266
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• 2004

The parathyroid hormone plays a major role in the metabolism of calcium and phosphorus. In hypoparathyroidism the parathyroid glands are atrophied or absent associated with autoantibodies against parathyroid tissue. Pseudohypoparathyroidism is a metabolic disease caused by the disturbance in peripheral action of parathormone, but parathormone level is normal. In general, patients with pseudohypoparathyroidism have short stature, round face, brachydactylia, obesity, mental retardation, cataracts & ectopic calcifications on soft tissues. Dental manifestations are enamel hypoplasia, delayed eruption, blunting of root apex, hypodontia, pulp calcification, thickened lamina dura, excessive caries & malocclusion. In this case, intraoral examination showed enamel hypoplasia on the erupted permanent teeth & hypermobility on the remaining deciduous teeth. From the radiographic view severe dental anomalies were observed on canines and shortening and blunting of root apex was observed on mandibular incisors. Pathologic root resorption was also observed on deciduous teeth.

• The korean journal of orthodontics
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• v.25 no.2 s.49
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• pp.209-221
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• 1995

The purpose of this study was to obtain the lingual morphology(angulation, inclination, horizontal and vertical contour) and lingual arch form of Korean adult with normal occlusion in order to provide the basic datas for lingual brackets and ideal lingual archwire. Dental models of thirty person with normal occlusion(Male : 16, Female :14) were selected for this study. Crown angulation, inclination. horizontal and vertical contour of lingual surfaces from Lt. 1st molar to Rt 1st molar of both upper and lower arch were measured. Lingual arcform was studied from copied papers of dental models attached Fujita lingual bracket. The results of this study were summarized as follows: 1. The average angulation and inclination of lingual surfaces of all tooth types for Korean adults with normal occlusion were obtained. 2. The average horizontal and vertical contour of lingual surfaces of all tooth types were obtained. 3. There were similar figures in horizontal and vertical contour of lingual surfaces between upper and lower molars, upper and lower premolars, upper and lower canines, upper central and lateral incisors and lower central and lateeral incisors respectively. It was possible that the use of those contour of bracket bases in common. 4. The average of lingual archform was provided, which was arch-shaped from canine to canine, linear along the premolars and molars with small offset bend between them, and where canines and premolars met, it was bent in a crank- shape. 3. There was no difference between lingual archform of male and that of female, although lingual archform of female was smaller than that of male in lower arch.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.1
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• pp.82-86
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• 2001

Actinomycosis is chronic, granulomatous, suppurative and fibrosing disease caused by Actinomyces. Actinomyces are anaerobic, G(+), non-acid-fast, branched, filamentous bacteria. The most commonly found microorganism is Actinomyces israelii. Common site for isolation of actinomyces are dental plaque, dental caries, calculus, and tonsillar crypt. A breach in the integrity of the mucosa by direct trauma or following a fracture, tooth extraction, root canal therapy or some intraoral surgical procedure is thought to be the most likely portal of entry. This is a case report of 23 years old male with cervicofacial actinomycosis developed after extraction and treated with surgical excision and antibiotics.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.3
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• pp.543-548
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• 1997

The first permanent molar takes important place in the occlusion. Malposition of the lower first molar is frequently due to mesial migration, which is occurred by early exfoliation of the second deciduous molar or proximal caries of deciduous teeth. Above things happen without any consideration of space maintainer, prompt measures for space regaining have to be started. Especially in the case with early loss of the second deciduous molar, it has been said that there is no suitable appliance for maintaining the space before the eruption of the permanent first molar. In distalizing the upper first molar, headgears have been routinely used, which its result was definitely depended on cooperation of the patients. Nowadays, appliances such as pendulum appliances, K-loop, magnets, which can be used without cooperation of the patients, are introduced. Jones Jig, one of the molar distalizing appliances, was used on the patients who visited department of pediatric dentistry in Seoul National University Dental Hospital complaining of no eruption space for the lower second bicuspid. Either removable splint or lingal arch was used as the anchorage. Jones Jig was favorably used in the lower molar, where vestibule is shallow, and this is a case report on the satisfactory result thereof.

• Restorative Dentistry and Endodontics
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• v.26 no.1
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• pp.9-15
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• 2001

통상적인 근관형성 과정에서 근관형태의 직선화 경향을 발견할 수 있으며, 그 결과 만곡이 심한 근관에서 이상적인 근관형태를 얻기가 어렵다. 이를 극복하기 위한 많은 기구들과 근관 성형법들이 개선되고 소개되었다. 본 연구에서는 최근에 개발된 직사각형의 단면을 가지는 stainless steel file인 RT file과 Flex-R file, K-file을 이용하여 만곡근관 형성 후 최종 근관형태를 비교하여 각 file을 평가하고자 한다. 본 실험은 Bramante등의 방법을 변형하여 술 전의 근관형태와 술 후의 근관형태를 비교하였다. Schneider의 방법을 변형하여 3차원적 만곡을 계산하여 12도에서 36도 이내에 만곡도를 가진 근관을 선택하였다. 49개의 발거된 상악대구치 협측근관이나 하악대구치 근심근관을 3개의 군으로 나누고 레진과 플라스틱으로 제작된 mold에 투명한 교정용 레진으로 매몰하였다. 근첨에서 2.5, 5, 8mm지점에서 절단하여 각 mold에서 재조립한 후 다음과 같이 근관형성을 시행하였다. 제 1군은 SS K-file을 이용하여 step-back 방법 ; 제 2군은 Flex-R file을 이용하여 balanced force 방법 ; 제 3군은 RT file을 이용하여 step-back 방법으로 근관 형성하였다. 술 전과 술 후에 각 시편들을 체현미경으로 사진촬영하여 근관 중심 위치 이동률, 근관형성으로 삭제된 상아질양, 근관형성 후 모양을 Sigma scan/ image software program으로 계산하고 One way ANOVA로 통계적 유의성을 검증하여 다음과 같은 결론을 얻었다. 1. RT file이 치근단에서 K-file보다 유의성 있게 근관의 중심을 유지하는 것으로 보였다. 치아 중앙부에서는 RT file과 Flex-R file이 K-file에 대해 유의성 있게 우수한 것으로 나타났다. 2. 근관형성 후 삭제된 상아질양에서는 치근단에서 RT file이 적게 나왔으나 유의성은 없었다. 3. 근관형성 후 절단면 모양은 원형, 타원형, 불규칙한 형태들이 다양하게 나타났고 각 군간에 유의성 있는 차이는 없었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.1
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• pp.49-57
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• 2006

Mandibular fractures have higher incidence rate compared to facial bone fractures because of relatively prominent form. Specially, mandibular angle fractures were known as common fracture site because of morphological anatomic structure. The mandibular third molar appears to be the most frequent impacted tooth. The mandibular third molar have influence on mandibular angle fractures according to it's eruption state. Also, the mandibular angle fracture including the third molar may influence on post operative infection whether the third molar is in impacted or extracted state when reduction of fracture site is operated. The presence or absence and degree of impaction of the mandibular third molar were assessed for each patient and were related to the occurrence of the mandibular angle fracture. The extraction or non extraction of the mandibular third molar were related to the occurrence of the post operative infection in the reduction of mandibular angle fractures. In the presence of mandibular third molar, the possibility of mandibular angle fractures were relatively common. When viewing the mandibular third molar at occlusal plane, the possibility of mandibular angle fractures were high in the class C group. The possibility of mandibular angle fractures were high in the mesial angulation and partial impaction. There was a statistically significant difference(P<0.05). In complete erupted mandibular third molar, the possibility of post operative infection occurs quite often, but there was no statistical significant difference(P>0.05). In the extracted or non extracted of mandibular third molar, the post operative infection showed no statistical significant difference(P>0.05). With the results mentioned above, mandibular third molar was significantly more susceptible to mandibular angle fracture. In the reduction of mandibular angle fracture, it was recommended that mandibular third molar should be extracted especially in case of pericoronitis, periodontitis and other infections.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.3
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• pp.207-217
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• 2014

The purpose of the present study was to evaluate the relationship between the malocclusion and dental caries in adolescents with permanent dentition. The subjects of the study were 385 adolescents aged 12 to 15 years. Dental Aesthetic Index (DAI) and DMFT index were recorded as clinical indicators of malocclusion and dental caries. The mean Dental Aesthetic Index (DAI) score of the subjects was 12.42 and the mean DMFT index of the subjects was 2.89. Four students (1.04%) were included in the group of orthodontic treatment mandatory, which signifies the handicapping malocclusion. Moreover, the result of gender-specific analysis of the DAI components observed that the prevalence of midline diastema and mandibular overjet were significantly higher among boys (p < 0.05). In 7 components (missing teeth, incisal segment crowding, maxillary anterior irregularity, mandibular anterior irregularity, mandibular overjet, anterior openbite, antero-posterior molar relationship) among the 10 DAI components, abnormal groups showed significantly higher DMFT index than normal groups (p < 0.05). The subjects in the group of definite to handicapping malocclusion (DAI ${\geq}$ 26) showed significantly higher DMFT index than the subjects in the group of minor or no malocclusion (p < 0.01). In addition, the DAI score had significant positive linear correlation with the DMFT index (r = 0.584, p < 0.01). Consequently, the current findings suggested a positive relationship between the malocclusion and caries prevalence. And several specific types of malocclusion were supposed to be significantly correlated with dental caries.