• Restorative Dentistry and Endodontics
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• 제18권2호
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• pp.291-316
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• 1993

Restorative procedures can lead to tooth fracture due to the relatively small amount of the remaining tooth structure. It is essential to prevent fractures by having a clear concept of the designs for cavity preparations. Among the several parameters in cavity designs, profound understanding of isthmus width factor would facilitate selection of the appropriate cavity preparation for a specific clinical situation. In this study, MO amalgam cavity were prepared on maxillary first premolar and filled with amalgam. Three dimensional, model with 1365 8-node brick elements was made by serial photographic method. In this model, isthmus was varied in width at 1/4, 1/3, 1/2 and 2/3 of intercuspal width and material properties were given for three element groups, i.e., enamel, dentin and amalgam. A load of 500 N was applied vertically on amalgam and enamel. In case of enamel loading, 2 model (with and without amalgam) was compared to consider the possibility of play at the interface between tooth material and amalgam. These models were analyzed with three dimensional finite element method. The results were as follows: 1. The stress was concentrated on the facio-pulpal line angle and distal marginal ridge of the cavity. 2. With the increase of the isthmus width, the stress spread around the facio-pulpal line angle and the area of stress concentration moved toward the proximal box. 3. In case of narrow isthmus width, the initiation point of crack would be in the area of isthmus corner of the cavity, and with the increase of the isthmus width, it would move toward the proximal box and at the same time the possibility of crack increase at the distal marginal ridge. 4. The direction of crack progressed outward and downward from the facio-pulpal line angle, and with the increase of the isthmus width, it approximated vertical direction. At the marginal ridge, it occurred in vertical direction. 5. It would be favorable to make the isthmus width narrower than a third of the intercuspal width, and to cover the cusp if isthmus width were wider than half of the intercuspal width. 6. It is necessary to apply the possibility of play to the finite element analysis.

• 대한장애인치과학회지
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• 제3권2호
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• pp.87-90
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• 2007

$DIFOTI^{(R)}$ 가시광선 파장을 이용하여 방사선 노출 없이도 실시간으로 교합면, 인접면, 평활면 우식, 재발성 우식 및 치아 파절이나 불소증 등을 효과적으로 진단할 수 있는 영상 장비이다. 시진 및 방사선 사진에 비해 치아 우식 탐지에 있어서 민감도가 매우 높은 것으로 나타나고 있으며, 이를 통해 치아의 탈회를 조기 진단하여 보다 보존적인 치료가 가능하리라 사료된다.

• 대한치과보철학회지
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• 제38권3호
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• pp.366-374
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• 2000

FRC/ceromer system provides the clinician with a durable, flexible, and esthetic alternative to conventional porcelain fused to metal crowns. FRC is the matrix which is silica-coated and embedded in a resin matrix. The ceromer material which is a second generation indirect composite resin contains silanized, microhybrid inorganic fillers embedded in a light-curing organic matrix. FRC/ceromer restoration has a several advantages: better shock absorption, less wear of occluding teeth, translucency, color stability, bonding ability to dental hard tissues, and resiliency. It has versatility of use including inlay, onlay, single crown, and esthetic veneers. With adhesive technique, it can be used for single tooth replacement in forms of inlay adhesion bridge. In single tooth missing case, conventional PFM bridge has been used for esthetic restoration. However, this restoration has several disadvantages such as high cost, potential framework distortion during fabrication, and difficulty in repairing fractures. Inlay adhesion bridge with FRC/ceromer would be a good alternative treatment plan. This article describes a cases restored with Targis/Vectris inlay adhesion bridge. Tooth preparation guide, fabrication procedure, and cementation procedure of this system will be dealt. The strength/weakness of this restoration will be mentioned, also. If it has been used appropriately in carefully selected case, it can satisfy not only dentist's demand of sparing dental hard tissue but also patient's desire of seeking a esthetic restorations with a natural appearance.

• 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.

• 대한심미치과학회지
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• 제9권1호
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• pp.42-46
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• 2000

치아형태라고 하면 따분하고 재미없는 것으로 생각하기 쉽지만, 치과임상에서 아주 중요한 기초를 형성하고 있다. 지대치형성은 치과보철수복의 첫 단계로서, 좋은 지대치형성은 좋은 보철물로 연결된다. 또한 치과보철 수복의 대부분은 원래의 치아형태수복에 맞추어져 있어서, 치아형태와 지대치형성은 많은 상관성을 가지고 있을 것이라고 유추해 볼 수 있다. 그러나 통상적으로 알고 있는 치아형태는 교합변형태로만 인식하고 있어서, 지대치형성시 치아형태가 큰 도움을 주지는 못하는 실정에 있다. 물론 교합면형태도 중요하지만 그외의 여러형태도 치과임상에 있어서 결코 무시할 수 없다. 필자는 지대치형성에서 고려해야 할 치아형태와 임상적 중요성에 대해서 언급하여 치과의사선생님들의 임상에 도움을 주고자 한다.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 춘계학술대회
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• pp.258-258
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• 2001

Fiber-reinforced materials have highly favorable mechanical properties. and their strength-to-weight ratios are superior to those of most alloys. When compared to metals they offer many other advantages as well. including non-corrosiveness. translucency. good bonding properties. and ease ofrepair. Fiber-reinforced materials can be categorized to pre-impregnated. impregnation required. dental laboratory products. chairside products and prefabricated posts. so it is not suprising that fiber-reinforced composites have potential for use in many applications in dentistry. Fiber-reinforced materials can be utilized in frameworks for crowns. anterior or posterior fixed prostheses. chairs ide tooth replacements. periodontal splints. customized posts. prefabricated posts. orthodontic retention. denture reinforcements and in implants dentistry. To realize the full potential of using fiber-reinforced composite restorations. it is essential that the clinician and laboratory technician understand concepts of tooth preparation and framework design. Also practitioner may appreciate the background information and other details about the materials themselves so that identify the rationale for their use in various clinical situations. select well-suited materials. and carry out related procedures. Understanding the material properties and take many attentions. fiber-reinforced materials will give more esthetic. more easy. more strong and more reliable restorations.ations.

• 대한치과의사협회지
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• 제57권9호
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• pp.524-528
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• 2019

With the advances of CAD-CAM (computer-aided design and computer-aided manufacturing) technology, the field of modern clinical dentistry has been dramatically changed. The first step in the digital workflow for tooth-supported dental prosthesis is a data acquisition with intraoral digital or conventional impression techniques. For the accuracy of intraoral digital impression data, the basic principles of conventional impression should be applied. It is necessary to obtain a good visibility with properly-dried field and well-exposed margin of the prepared abutment. Currently, the equi- or supra-gingival finish line can be recommended as an indication for intraoral digital impression. The scan data are generally exported to '.stl' file format, which has only morphological information of black and whitem while '.obj' file format can store data on color and texture.

• 대한의생명과학회지
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• 제28권1호
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• pp.50-57
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• 2022

In this study, we tried to examine the possibility of developing a dental product such as tooth decay prevention and oral hygiene by manufacturing a natural polymer film for oral use. Natural polymer films were prepared from shark byproduct extract (SBE) and gellan gum (GG). As an antibacterial substance, the antibacterial activity of green tea extract against tooth decay-causing bacteria was measured. An film was prepared by adding green tea extract to the composition of SBE and GG. The mechanical, solubility, moisture content and antibacterial function of the prepared film were investigated in detail. Also, the incorporation of GTE into the SBE/GG film improved the physical performance of the film. Increasing the content of GTE improved the antioxidant and antibacterial properties of the film. Formulation of antimicrobial SBE/GG film containing green tea extract was established and these results evidently showed potential for cavity prevention products application.

• 치위생과학회지
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• 제11권2호
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• pp.121-127
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• 2011

본 연구는 임플란트 시술환자의 시술 전 기대와 시술 후 만족도를 비교하여 임플란트 시술에 대한 환자만족도를 향상시키고자 실시하였으며, 서울, 경기 및 천안에 거주하는 임플란트 시술 경험자 158명을 대상으로 조사 분석하였다. 그 결과는 다음과 같은 결론을 얻었다. 1. 임플란트 시술 내역을 살펴본 결과 1개를 시술한 응답자가 40.5%로 가장 많았으며, 평균 개당 가격은 150만 원 이상 -200만 원 미만이 36.1%였다. 임플란트 선택 동기는 23.4%가 '보철물을 하기 위해 다른 치아를 깍지 않아서'라고 답하였다. 2. 일반적 특성에 따른 임플란트 시술의 기대를 조사한 결과 전반적으로 여자가 남자보다 기대가 높았으며, 특히 '일반 보철물에 비해 수명이 길다'는 여자가 4.29, 남자가 3.87로 유의한 차이가 있었다(p=.003). 연령별은 '색상이나 모양이 자연치와 비슷하다.'는 기대가 20대에 4.38로 가장 높았다(p=.013). 일반적 특성에 따른 만족도는 역시 '보철물을 하기 위해 다른 치아를 깍지 않는다.'는 항목에서 20대가 4.57로 가장 만족하고 있었다(p=.002). 3. 임플란트 시술 전에 기대와 시술 후 만족도를 비교한 결과 '턱뼈 흡수를 막아주므로 얼굴외형이 유지된다.'의 항목에 대해 시술 전 기대도는 3.70이었으나 만족도는 3.87로 높아졌으며(p=.020), '보철물을 하기 위해 다른 치아를 깍지 않는다.'의 항목은 시술 전 3.95의 기대에서 시술 후 4.23의 만족도를 보여 통계적으로 유의했다(p<.001). 4. 임플란트 시술에 관한 전체적인 만족도는 4.25, 추천 의사는 4.18, 재시술 의사는 4.17의 만족 결과를 보였다. 이상의 결과를 통하여 임플란트 환자는 여러 제약에도 불구하고 시술에 관한 전반적인 만족정도가 높았다. 치과 의료진들은 향후에도 환자들의 기대감에 대응하는 만족도를 충족시키도록 계속관리 등의 세심한 관심이 필요하다.

• Restorative Dentistry and Endodontics
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• 제22권1호
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• pp.61-75
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• 1997

The bond strengths of composite resin to tooth dentin vary with the methods of cavity preparation and surface treatment. Recent developments in techniques of dentinal surface treatment have renewed interest in microabrasive as a means of tooth preparation, The purpose of this study was to determine the effects of a new method of cavity preparation on the bond of composite resin to dentin. Freshly extracted 144 healthy human third molars were used in this study. The dentin surfaces prepared with #600 SiC abrasive paper were divided into control and air abrasion groups according to the method of dentin surface preparation using different combinations of delivery pressure, time, and acid etching. The shear bond strengths were measured after the composite resin (Clearfil Photo Bright) was bonded to prepared dentin surfaces by light-curing using a dentin bonding system (All-bond 2), In addition, the average surface roughness was measured to investigate the effect of differently prepared dentin surfaces on the shear bond strengths. The surface changes of prepared dentin and the debonded dentin surfaces were observed with SEM (S-2300, Hitachi Co., Japan). The following results from this-study were obtained ; 1. There was no significant difference of shear bond strengths according to the changes of delivery pressure and time. 2. The shear bond strengths were lower than the control in the air abraded-only groups, but those of the additional acid-etched groups were higher than the control. 3. The shear bond strengths to all air-abraded surfaces were increased by acid etching. 4. The correlation between shear bond strengths and surface roughness was not certain, although the mean surface roughness of all air-abraded surfaces has increased evidently while it has slightly decreased for additional acid etching. 5. On SEM examination, the dentinal tubules were almost occluded in the air abraded-only groups, but those were opened in the additional acid-etched groups. 6. The debonded surfaces were showed adhesive failure mode in the air abraded- only groups, while those were showed mainly the mixed and cohesive failure mode in the additional acid-etched groups. These results suggest that the layer produced during cavity preparation or surface treatment with air abrasion must be removed for maximum bond strength of composite resin to dentin.