• Journal of Korean Dental Science
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• 제13권2호
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• pp.52-58
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• 2020

Purpose: Using two types of electronic apex locators, this study aimed to investigate the differences in accuracy according to the evaluator and equipment. Materials and Methods: Artificial teeth of the lower first premolars and two mandibular acrylic models (A and B) were used in this study. In the artificial teeth, the pulp chamber was opened and the access cavity was prepared. Using calibrated digital Vernier calipers, the distance from the top of the cavity and the root apex was measured to assess the actual distance between two artificial teeth. The evaluation was conducted by 20 dentists, and each evaluator repeated measurements for each electronic apex locator five times. The difference between the actual distance from the top of the cavity to the root apex and the distance measured using electronic measuring equipment was compared. For statistical analysis, the Friedman test the Mann-Whitney U-test were conducted and the differences between groups were analyzed (α=0.05). Result: As for the accuracy of measurement according to the two types of electronic apex locators, the value of the measurement error was 0.4753 mm in Dentaport ZX and 0.3321 mm in E-Cube Plus. Moreover, electronic apex locators Dentaport ZX and E-Cube Plus showed statistically significant differences (P<0.05). As for the difference in the accuracy of the two types of electronic apex locators according to the evaluator, the resulting values differed depending on the evaluator and showed a statistically significant difference (P<0.001). Conclusion: Electronic apex locator E-Cube Plus showed higher accuracy than did Dentaport ZX. Nevertheless, both types of electronic apex locators showed 100% accuracy in finding the region within root apex ±0.5 mm zone. Furthermore, according to the evaluator, the two electronic apex locators showed different resulting values.

• 대한소아치과학회지
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• 제33권2호
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• pp.165-172
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• 2006

오랜 기간동안 다양한 약제를 통한 직접 치수복조술이 시도되어 왔다. 그 중 가장 보편적으로 사용된 약제는 수산화칼슘이다. 하지만 유치에서 수산화칼슘을 이용한 직접 치수복조술의 성공률은 생활치수절단술에 비해 낮다고 보고되어 왔다. 수산화칼슘의 단점으로 인해 다른 치수복조제를 찾기 위한 많은 연구가 있었으며 최근 여러 연구가들은 치수복조제로 접착용 레진의 이용을 제안하였다. 그들은 노출된 치수에 접착용 레진이 적용되었을 때 임상적 증상이 없이 염증이나 치수괴사가 없다고 주장하였다. 이 연구의 목적은 유치에서 기계적으로 노출된 생활치수에 치수복조제로써 수산화칼슘과 접착용 레진을 적용하여 단 기간동안의 예후를 비교해 보고, 또한 각각의 직접 치수복조술을 시행한 유치에 있어 생리적인 치근흡수 유무에 따른 예후의 차이를 비교해보기 위함이다. 와동형성 중 기계적으로 치수가 노출되어 생활 치수인 유치 41개를 대상으로 하였다. 그중 접착용 레진으로 치수복조제로 사용한 치아 21개를 1군으로 하였고, 수산화칼슘을 이용한 치아 20개를 2군으로 하였다. 그리고 제 1군과 2군의 치아들은 치근단방사선 소견을 통해 생리적인 치근흡수의 유무여부에 따라 다시 세분되었다. 모든 치아는 복합 레진으로 수복하였으며, 시술 3개월 후 타진반응, 냉 검사, 전기치수검사 등의 치수 생활력검사와 치근단방사선 소견으로 성공여부를 판단하였다. 결과는 다음과 같다. 1. 1군과 2군 사이의 성공률에는 유의한 차이가 없었다. 2. 각 군에서 생리적인 치근흡수가 없는 유치보다 있는 유치에서 성공률이 현저히 높았다. 3. 전치와 구치사이의 성공률에는 유의한 차이가 없었다.

• 대한치과의사협회지
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• 제50권7호
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• pp.384-393
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• 2012

Successful treatment of a badly broken down tooth with pulpal disease depends not only on good endodontic therapy, but also on good prosthetic reconstruction of the tooth after endodontic therapy is completed. The ideal treatment of endodontically treated teeth has been widely and controversially discussed. Endocrown is a restorative option for endodontically treated teeth. Endocrown design incorporates the core and short post into the crown as a single restoration. The preparation of endocrown consists of a circular equigingival butt-joint margin and central retention cavity of the entire pulp chamber instead of employing intraradicular posts. This design significantly increases the surface area of the preparation available for cementation. It is particularly useful in young patient teeth for long-term provisional restoration and in teeth with short clinical crowns. This technique represents a promising and conservative method for the treatment of endodontically treated teeth that require long-term protection and stability. Endocrown can be considered as a feasible alternative to full crowns or composite overlays for the restoration of non vital teeth.

• 대한치과보철학회지
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• 제8권1호
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• pp.90-94
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• 1968

The author attempted to study the role of liners as a barrier against the penetration of the acids released from the liquid of dental cements. Six different kinds of liners were used in this study and the depth of penetration of the acids of phosphate and silicate cements were measured ands following conclusions were obtained. 1. All the liners successfully prevented penetration of the acids released from phosphate and silicate cements. 2. When silicate cements were placed into the cavity without any liners, free acids were liberated continuously and thus may give injuries to the pulp tissue.

• 대한치과의사협회지
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• 제55권8호
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• pp.565-573
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• 2017

Root canal perforations are defined as the communication between the pulp cavity, the periodontal tissue and alveolar bone. The occurrence of perforations during endodontic treatment is reported to range from 2.3%~12%, which is not a complication rarely happens. Perforations have iatrogenic or pathological etiologies that involve caries or resorption. It leads to inflammation and the destruction of periodontal fibers and alveolar bone, followed by periodontal defects. Mineral trioxide aggregate (MTA) is currently the most indicated material for repair of root perforation, because of its favorable biocompatibility and sealing ability. Using magnification with dental operating microscope enhance the accessibility and visibility to manage the root perforation. It is important to diagnose and repair perforations immediately if possible.

• Restorative Dentistry and Endodontics
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• 제1권1호
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• pp.8-10
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• 1975

This study is to determine or detect deposition of mercury particles emitted from dental amalgam fillings. Amalgam fillings were carried out routinely on the dogs' teeth. (CIV cavities) Mercury which contains about 200${\mu}Ci$ of $^{197}Hg$ was employed on this purpose in each cavity. Radioactivity was measured by means of well type scintillation counter from saliva and mucous membrane of surrounding tissue. The C. P. M. value from the saliva was highest, mucous membrane was moderate and least on blood and fecs, as shown table on I. II. III. IV. 1. C.P. Mvalue from Saliva reveals 114 to 135 (lowest and highest) throughout the measuring period until 41 hours. 2. From blood samples no significant value was found. 3. CPM value from feces at2nd day and 4th day was about 90. 4. The highest and lowest CPMvalue from marginal gingiva was 465 and 209 respectively. Palatine showed 281 and 189, esophagus 179 and 165, and pulp from experiment tooth 190 and 104 respectively.

• 한국치위생학회지
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• 제4권2호
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• pp.277-291
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• 2004

The purpose of this study is to analyze the dental hygienists' overall performance in operative restoration and the clinical performance in operative restoration according to dental hygienists' career and to provide basic data for establishing the appropriate range of dental hygienists' work. Subjects of this study are 339 dental hygienists working at dental clinic and hospital nationwide, selected by their working place, career, type of clinic, and location of clinical institution. The distribution of people who responded to the survey shows that 81 belong to beginner level(less than 2 years since entering clinic), 115 intermediate level(2 to 3 years since entering clinic), 81 higher level(4 to 5 years since entering clinic) and 62 advanced level(more than 6 years since their entering clinic). In terms of the types of clinical institution, 178 belong to dental clinics and 161 belong to dental hospitals. The survey used in this study are focused on perception about clinical performance in operative dentistry and adequacy of the work. Operative dentistry consists of operative restoration and endodontic therapy. The operative restoration consists of 15 categories such as patient welcoming, examination and diagnosis, planning of treatment, anesthesia, control of moisture, cavity preparation, pulp protection, matrix band application, amalgam filling, resin filling, glass ionomer cement filling, abrasive strip removal, rubber dam removal, bite check and polishing, patient education, and arrangement. The reliability was Cronbach's Alpha .9453. SPSS 10.0 for Windows was used to analyze the responses. One way ANOVA was utilized to verify the differences in the dental hygienists' job performance in operative restoration and their job performance according to career. When significant difference was found. Duncan multi comparison post hoc was done. To sum up the results of this study, patient welcoming look the first place in the operative restoration. It was followed by patient education, examination and diagnosis, introducing treatment plan, resin filling, glass ionomer cement filling, amalgam filling, bite check and polishing, anesthesia, pulp protection, control of moisture, abrasive strip removal, cavity preparation, matrix band application, rubber dam removal, and anesthesia. In terms of the clinical performance by career, there were significant differences in 19 activities such as medical eraluation, oral examination, patient charting, intra oral readio graphs, firm developing fixing mounting, curing light gun, education of attention content after operation. Based on the results of this study, the specific range of operative restoration for dental hygienists should be focused on providing basic data for dentists' diagnosis, alleviation of fear and aching accompanied by injection and anesthesia, data providing for dentists' decision of anesthesia degree, and maximization of control of moisture.

• 한국어병학회지
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• 제33권1호
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• pp.7-14
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• 2020

실험실에서 순환여과시스템으로 5-6개월 사육하던 넙치 치어에서 아가미의 심한 빈혈을 나타내는 질병이 발생하였다. 현미경관찰에서 아가미에서는 유충이, 입천정에서는 성숙한 성충이 관찰되었다. 성충의 체장은 5.60-9.32 mm이며 방추형 몸의 길이는 3.83-6.32 mm, 부착기는 방추형 몸에서 부터 연결된 isthmus의 끝부분에 꽃자루 모양으로 존재하였고 부착기의 끝에는 8개의 파악기가 있었다. 충의 형태학적 관찰로부터 단생류에 속하는 Neoheterobothirum hirame로 동정하였다. 감염어의 적혈구용적는 평균 10.3±2.8%로 정상 넙치의 31.4±4.2%보다 현저히 낮았다. 병리조직학적으로 N. hirame에 감염 된 넙치는 아가미 새판과 새엽을 흐르는 혈관내의 적혈구가 감소하고 비장의 적수(red pulp) 영역이 감소되고 간세포는 위축이 관찰되었다. 이상의 결과로부터 넙치에 심한 빈혈을 일으킨 원인은 N. hirame인 것을 밝혔다. 이 연구는 순환여과식 사육시스템에서는 사육수의 교환이 적으므로 소독장치가 충분하지 못할 경우 병원체의 증식이 문제가 될 수 있는 예를 보이고 있다.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 춘계학술대회
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• pp.247-251
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• 2001

;A dental developmental anomaly is defined as an isolated aberration in tooth form, caused by a disturbance or abnormality which occurred during tooth development. There are numerous types of dental anomalies, and a considerable variation in the extent of the defects occurs with each type. Teeth with these anomalies pose unique challenges. Since the defects are not always apparent clinically, they can confuse diagnosticians investigating the etiology of pulpal pathosis. When endodontic treatment is required, the defects often hinder access cavity preparation and canal instrumentation. Treatment planning also becomes more challenging, since the defects can create complicated periodontal problems, and the malformed teeth can be difficult to restore, particularly those weakened by endodontic therapy. Fusion is defined as the joining of two developing tooth germs resulting in a single large tooth structure. The incidence of fusion is < 1% in the Caucasian population, and it is believed that physical force or pressure produces contact of the developing teeth. Clinically and radiographically, a fused tooth usually appears as one large crown with at least partially separated roots and root canals. There may be a vertical groove in the tooth crown delineating the originally separate crowns. Dens invaginatus is a deep surface invagination of the crown or root that is lined by enamel. Teeth in both maxillary and mandibular arches may be affected, but the permanent maxillary lateral incisor is the tooth most commonly involved. Studies have revealed an incidence ranging from 0.25% to as high as 10%. The invagination ranges from a slight pitting to an anomaly occupying most of the crown and root. The invagination frequently communicates with the oral cavity, allowing the entry of irritants and microorganism either directly into pulpal tissues or into an area that is deparated from pulpal tissues by only a thin layer of enamel and dentin. This continuous ingress of irritants and the subsequent inflammation usually lead to necrosis of the adjacent pulp tissue and then to periapical or periodontal abscesses. If the invagination extends from the crown to the periradicular tissue and has no communication with the root canal system, the pulp may remain vital. Recommended treatment of fused tooth and dens invaginatus has been reported in the endodontic literature. This case report describes the endodontic treatment of a maxillary laterl incisors having fused crown and dens invaginatus.natus.

• 대한소아치과학회지
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• 제11권1호
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• pp.169-179
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• 1984

The purpose of this study was to observe the effect of dental varnish applied with fluoride to dental pulp by comparing the groups of commercial fluoride product $Duraphat^{(R)}$, $Copalite^{(R)}$ after 1 Mole sodium fluoride application, Cavity $Sealer^{(R)}$ after 1 Mole sodium fluoride application with the control group not applied the dental varnish. After Cl V Cavity form was prepared on the buccal surface of the crowns with the total 75 teeth by using 5 dogs, average weight of 13.2Kg, dental varnish and silver analgram were placed. This study was performed by 3, 7, 21, 28, 56 days each. The dogs were sacrificed to extract the teeth, cut at the apical one fourth, and prepared histologic examination by fixing with 10% buffered formalin perfusion at sacrifice and decalcification in 10% nitric acid. The specimens were embedded in paraffin, stained with Hematoxylin and Eosin, and serially sectioned with 6 ${\mu}$width each. Microscopic evaluation of serial sections at the various time periods among the different groups revealed the following results: 1. In the control group, the marked change of the odontoblastic layer was showed on the 3 days group, and it was decreased gradually. Healing response, such as hyperplasia, was seen on the 28 days group and it was continued to the 56 days group. 2. In the experimental group with Cavity $Sealer,^{(R)}$ a slight hemorrhage was seen in the odontoblastic layer on the 3 days group, and the healing response with the hyperplasia of the odontoblast was showed on the 21, 28 days group. It was completely healed on the 56 days group. 3. In the Duraphat R group, a slight hemorrhage showed on the 3 days group and the disarrangement of the Odontoblastic layer was seen on the 7, 21, 28 days group. Odontoblasts showed hyperplasia on the 28 days group, and healed completely on the 56 days group. 4. In the $Copalite^{(R)}$ group, the 7 days group showed remarkable hemorrhage in the odontoblastic layer and stroma, and also it showed reticular degeneration with the disarrangement of the odontoblastic layer and congestion. Each group showed disarrangement. Healing ability of this group was greater than that of the control group, but less than that of the $Duraphat^{(R)}$ and Cavity $Sealer^{(R)}$ group.