• Mass Spectrometry Letters
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• 제9권4호
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• pp.110-114
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• 2018

Since accumulation of chemicals in deciduous teeth can occur from the second trimester of fetal development to shedding, a deciduous tooth has been considered as an attractive biomatrix for estimating individual chemical exposures recently. Therefore, detection of organic chemicals from teeth has received an increasing attention in exposomics research. Most previous studies on organic chemical analysis of teeth not only focused on a few targeted chemicals but also ignored potential contaminants from an enamel surface or a dental pulp. Recently, our group started developing a multi-class organic analysis method for deciduous teeth and tried to find a proper incubation condition of tooth materials. Our results showed that incubation with methanolic HCl provided the best performance among tested.

• Restorative Dentistry and Endodontics
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• 제19권1호
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• pp.73-84
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• 1994

Using a model system that can compare the before and after of canal preparation in the same tooth, we measured the area of the cross section, and canal wall thickness of the distal portion of the mesial root of the mandibular molar, and compared the amount of reduction in the canal using hand flared preparation the Gates-Glidden drill flared preparation according to the changes in the MAF. The results were as follows. 1. After canal preparation, the canal wall thickness had no significant difference between the hand flared preparation and Gates-Glidden drill flared preparation. 2. The canal wall thickness, after canal preparation, there was no significant difference between the sizes of the MAF. 3. The area variation range of each cross section of root had no significant difference between MAF size and methods of canal preparation. 4. After canal preparation, the frequency of the canal wall thickness under 0.5mm showed 3.5mm below the furcation to be the most frequent with statistical significance(p<0.05). 2mm below the furcation and 5mm below the furcation followed but there was no statistical significance. 5. The danger zone of the mesial root of the mandibular molar seems to be around 3.5mm.

• The Journal of Advanced Prosthodontics
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• 제6권6호
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• pp.444-450
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• 2014

PURPOSE. To compare the accuracy of marginal and internal adaptation of zirconia (Zr) copings fabricated on anatomic (A), semi-anatomic (SA) and non-anatomic (NA) occlusal surface preparations. MATERIALS AND METHODS. 45 extracted bicuspid teeth were prepared for receiving zirconia crowns, with different occlusal preparation designs A=15, SA=15 & NA=15. The Zr copings were fabricated by using CAD4DENT, CAD/CAM. The copings were adjusted, cemented and were cross sectioned centrally from buccal cusp tip to lingual cusp tip into mesial and distal halves. The copings were examined under electron microscope at ${\times}200$ magnification and the measurements were recorded at 9 predetermined areas in micrometers. RESULTS. Overall mean gap values for the three groups was found to be $155.93{\pm}33.98{\mu}m$ with Anatomical Occlusal preparation design having the least gap value of $139.23{\pm}30.85{\mu}m$ showing the best adaptation among the groups. Post Hoc Tukey's test showed a statistically significant difference (P=.007) between the means of gap for A & NA preparation designs. Measurements recorded at 9 predetermined points showed variations for the three groups. CONCLUSION. Anatomical occlusal preparation designs resulted in better marginal and internal adaptation of Zr copings. There is a considerable variation between the measured marginal and internal gap values for the Zr copings fabricated by the (CAD4DENT-CAD/CAM). This variation may be associated with the lack of standardization of the preparation of teeth, computerized designing of the coping for each tooth, cement used, uniform pressure application during the cementation of the copings, sectioning of the copings and the microscopic measurements.

• 대한장애인치과학회지
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• 제10권2호
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• pp.84-88
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• 2014

1. 순측접근법은 치수치료를 순측으로 시행한 후 변색된 순측의 치질을 확대하여 삭제하고 레진으로 순면전체를 수복함으로써 치수치료와 동시에 심미성을 회복할 수 있다. 2. 순측으로 치수치료를 시행하므로 시야가 확보에 유리하고 기구조작이 용이해 행동조절이 잘 되지 않는 어린이에게 추천된다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제37권
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• pp.8.1-8.6
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• 2015

Background: This study aimed to evaluate the clinical usefulness of autogenous fresh demineralized tooth (auto-FDT) graft prepared at the chairside for alveolar bone grafting during dental implant surgery. Methods: In total, 38 patients requiring both tooth extraction (for endodontic or periodontal reasons or third molar extraction) and alveolar bone regeneration for dental implant placement were included. Within 2 h after clean extraction, the teeth were prepared at the chairside to serve as bone graft material. In the same sitting, blocks or chips of this graft material were used to reconstruct defects at the osteotomy site simultaneously with or before implant placement. Twelve months after prosthesis fabrication and placement, the clinical findings and implant success rates were evaluated. Histological studies were randomly conducted for selected cases. Results: Clinical evaluation showed favorable wound healing with minimal complications and good bone support for the implants. No implant was lost after 12 months of function following prosthetic rehabilitation. Histological examination revealed new bone formation induced by the graft material. Conclusions: Chairside preparation of autogenous fresh demineralized teeth after extraction can be a useful alternative to the use of autogenous bone or other graft materials for the immediate reconstruction of alveolar bone defects to facilitate subsequent implant placement.

• Restorative Dentistry and Endodontics
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• 제38권3호
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• pp.105-112
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• 2013

While it is reasonably well known that certain dental procedures increase the temperature of the tooth's surface, of greater interest is their potential damaging effect on the pulp and tooth-supporting tissues. Previous studies have investigated the responses of the pulp, periodontal ligament, and alveolar bone to thermal irritation and the temperature at which thermal damage is initiated. There are also many in vitro studies that have measured the temperature increase of the pulp and tooth-supporting tissues during restorative and endodontic procedures. This review article provides an overview of studies measuring temperature increases in tooth structures during several restorative and endodontic procedures, and proposes clinical guidelines for reducing potential thermal hazards to the pulp and supporting tissues.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.594-594
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• 2001

Increased demand for esthetic restorations has promoted a growing interest in tooth-colored restorations even in the posterior regions. Preparation for specific types of indirect inlay and onlays may vary because of differences in fabrication steps for each commercial system and variations in the physical properties of the restorative materials. Preparations for indirect inlay/onlay basically are meant to provide adequate thickness for restorative material and at the same time a passive insertion pattern with rounded internal angles and well defined margins after deciding what type of restoration is indicated.(omitted)

• Restorative Dentistry and Endodontics
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• 제15권1호
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• pp.97-105
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• 1990

When conventional root canal treatment is failed or contraindicated, retrograde root canal filling following apicoectomy is a valuable procedure, aimed at hermetically sealing the root canal against leakage of irritants from the canal into the periapical tissue. In this in vitro investigation, to analyze apical microleakage electrochemically in teeth with different retrograde filling materials and preparation types, single - rooted tooth was cut 2mm from the apex and each Class I and Slot preparation was prepared. Experimental groups : Group 1. Amalgam filling with cavity varnish in Class I preparation Group 2. Scotchbond 2+Silux filling in Class I preparation Group 3. Gutta percha filling with ZOE cement in Class I preparation Group 4. Amalgam filling with cavity varnish in Slot preparation Group 5. Scotchbond 2+Silux filling in Slot preparation Each specimens was immersed in 1% solution of KCl, and applied a potential of 9V external power supply. Measurements of the current flow were obtained at 1, 2, 3, 7, 9, 12, 14, 18, 21, 25 and 28 day after immerson. Marginal microleakage were compared and evaluated. The results were as follows ; 1. The group filled with composite resin with dentin bonding agent shows lower apical microleakage value than the group filled with amalgam following varnish application (P<0.01). 2. In the group filled with gutta percha, apical microleakage value was the hightest 3. There was no significant difference between Class I cavity and Slot type cavity regardless of the used materials.

• 한국세라믹학회지
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• 제20권1호
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• pp.55-62
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• 1983

the preliminary work on the prepartion of fine hydroxyapatite powder and the synthesis of dense hydroxyapatite ceramic from the powder were investigated for the development of artificial bone and tooth materials for implants. The effects of the process variables such as compositions of the raw materials the initial pH of the solutions and sintering temperature on the physical properties were investigated in order to determine the optimum conditions for the fabrication of tooth implant material. As the initial pH of the solutions was increased in the range of 10-11.6 the initial particle size of precipitates was decreased thus the sinterability of precipitates was improved. It was found that the composition of calcium rich of 1.75 in Ca/P mole ratio exhibited better sinterability and mechanical strength of the apatite ceramics for example the highest value of Vicker's hardness obtained from the compositions of 1.75 in Ca/P mole ratio was 764±30 Kg/mm2 compared to the maximum value of 600 kg/mm2 obtained from the compositions of 1.67 in Ca/P mole ratio.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2003년도 제120회 추계학술대회 제 5차 한ㆍ일 치과보존학회 공동학술대회
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• pp.581-581
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• 2003

The purpose of this study was to search non-invasive and reproductive pulp test. Temperature of the crown surface was measured using the infrared thermography, and the pulp test was investigated with difference of crown temperature of the vital and the non-vital tooth in vitro and in vivo. Twenty extracted human maxillary central incisors were used in this study. Two sample teeth after access cavity preparation were arranged setting with one pair. Then, the each tooth wes estimated as the vital and the non-vital tooth.(중략)