• Restorative Dentistry and Endodontics
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• 제41권4호
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• pp.255-261
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• 2016

Objectives: This study aimed to analyze the mineral composition of naturally- and artificially-produced caries-affected root dentin and to determine the elemental incorporation of resin-modified glass ionomer (RMGI) into the demineralized dentin. Materials and Methods: Box-formed cavities were prepared on buccal and lingual root surfaces of sound human premolars (n = 15). One cavity was exposed to a microbial caries model using a strain of Streptococcus mutans. The other cavity was subjected to a chemical model under pH cycling. Premolars and molars with root surface caries were used as a natural caries model (n = 15). Outer caries lesion was removed using a carbide bur and a hand excavator under a dyeing technique and restored with RMGI (FujiII LC, GC Corp.). The weight percentages of calcium (Ca), phosphate (P), and strontium (Sr) and the widths of demineralized dentin were determined by electron probe microanalysis and compared among the groups using ANOVA and Tukey test (p < 0.05). Results: There was a pattern of demineralization in all models, as visualized with scanning electron microscopy. Artificial models induced greater losses of Ca and P and larger widths of demineralized dentin than did a natural caries model (p < 0.05). Sr was diffused into the demineralized dentin layer from RMGI. Conclusions: Both microbial and chemical caries models produced similar patterns of mineral composition on the caries-affected dentin. However, the artificial lesions had a relatively larger extent of demineralization than did the natural lesions. RMGI was incorporated into the superficial layer of the caries-affected dentin.

• Restorative Dentistry and Endodontics
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• 제43권4호
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• pp.45.1-45.11
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• 2018

Objectives: This study was conducted to evaluate fluoride release and the micro-shear bond strength of resin-modified glass ionomer cement (RMGIC) in casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-remineralized caries-affected dentin (CAD). Materials and Methods: Exposed dentin surfaces of 30 human third molar teeth were divided into 2 equal groups for evaluating fluoride release and the micro-shear bond strength of RMGIC to CAD. Each group was subdivided into 3 equal subgroups: 1) control (sound dentin); 2) artificially demineralized dentin (CAD); 3) CPP-ACP remineralized dentin (remineralized CAD). To measure fluoride release, 15 disc-shaped specimens of RMGIC (4 mm in diameter and 2 mm in thickness) were bonded on one flat surface of the dentin discs of each group. Fluoride release was tested using ion chromatography at different intervals; 24 hours, 3, 5, 7 days. RMGIC micro-cylinders were built on the flat dentin surface of the 15 discs, which were prepared according to the assigned group. Micro-shear bond strength was measured after 24 hours water storage. Data were analyzed using 1- and 2-way analysis of variance and the post hoc least significant difference test (${\alpha}=0.05$). Results: Fluoride detected in solutions (at all intervals) and the micro-shear bond strength of RMGIC bonded to CPP-ACP-remineralized dentin were significantly higher than those bonded to artificial CAD (p < 0.05). Conclusions: Demineralized CAD consumes more fluoride released from RMGIC into the solution for remineralization than CPP-ACP mineralized dentin does. CPP-ACP increases the micro-shear bond strength of RMGIC to CAD.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2002년도 추계학술대회
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• pp.706-706
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• 2002

No Abstract, See Full Text

• Restorative Dentistry and Endodontics
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• 제44권3호
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• pp.24.1-24.1
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• 2019

• Restorative Dentistry and Endodontics
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• 제30권1호
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• pp.49-57
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• 2005

이 연구의 목적은 all-in-one adhesive인 Adper Prompt $L-Pop^{TM}$과 $Xeno^{(R)}$ III를 우식이환 상아질에 다층 적용했을 때의 효과를 미세인장결합강도의 측정과 주사전자현미경을 이용한 파절양상의 관찰을 통해 알아보는데 있다. 교합면 우식이 있는 21개의 치아에서 편평한 상아질 면이 노출되도록 하여 감염 상아질을 제거한 후 3개씩 7개의 군으로 분류하였다. SM 군은 $Scotchbond^{TM}$ Multi-purpose를 적용하였다. LP1 군, LP2 군, LP3 군은 Adper Prompt $L-Pop^{TM}$을 각각 단층, 2층, 3층으로 적용하였다. XN1 군, XN2 군, XN3 군은 Xeno^{(R)}$ III를 각각 단층, 2층. 3층으로 적용하였다. 각각의 상아질 접착제 처리 후, 광중합레진인 $Filtex^{TM}$ Z-250을 10mm 높이로 적층 충전하였다. 각 치아는 가로와 세로의 길이가 각각 1 mm인 막대 모양의 절편이 되도록 수직으로 절단하였다. 그 후 미세인장결합강도를 측정하였다. 측정 후 파절된 시편을 주사전자현미경을 이용하여 파절양상을 살펴보았다. 각 군의 미세인장결합강도를 one-way ANOVA와 $95\%$ 신뢰도의 Scheffe's Test를 이용하여 분석하였다. 이 연구의 결과는 다음과 같다. 1. 미세인장결합강도를 측정한 결과, SM 군은 14.38{\pm}2.01$ MPa, LP1군, LP2 군, LP3 군은 각각 $9.15{\pm}1.81$ MPa, $14.08{\pm}1.75$ MPa, $14.06{\pm}1.45$ MPa로 측정되었고, XN1 군, XN2 군, XN3 군은 각각 $13.65{\pm}1.95$ MPa, $13.98{\pm}1.60$ MPa, $13.88{\pm}1.66$ MPA로 측정되었다. LP1 군은 다른 모든 군에 비해 낮은 미세인장결합강도를 나타내었고 (p < 0.05). LP1 군을 제외한 다른 모든 군 사이에는 유의한 차이가 없었다 (p > 0.05). 2. 파절양상을 관찰한 결과, LP1 군에서는 접착성 파절이 우세하게 나타났고, LP1 군을 제외한 다른 모든 군에서는 혼합형 파절이 주로 일어났다.

• 대한소아치과학회지
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• 제23권4호
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• pp.954-967
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• 1996

Laser application to modify healthy permanent dentin to improve microhardness and caries resistence has been previously reported but the physical modification and ablation thresholds of carious and sclerotic dentin has yet to be identified. This study determined the energy density required by modify (physical modification threshold, PMT) and remove (ablation threshold, AT) infected carious, affected and selerotic dentin compared to healthy permanent dentin. $1{\pm}0.25mm$ thick dentin sections(n=272) from extracted human teeth were used. Smear layer was removed 0.5M EDTA for 2 minutes. Utilizing three pulsed fiberopitc delivered contact lasers with different emission wavelengths($1.06{\mu}m$=Nd : YAG, $2.10{\mu}m$=Ho : YAG and $2.94{\mu}mEr$ : YAG). The energy density($J/cm^2$) was incrementally increased and the resulting tissue interaction classified on a scale from 0-6. A minimum of 5 repetitions/energy density were completed. Light microscopy(10-25X) was used to verify the physical modification(scale=3) and ablation thresholds(scale=4) of the various forms of dentin and the data were analyzed by logistic regression at the 95 % confidence interval. PMT and AT by the laser and the dentin types were: PMT and AT was lower in infected dentin than in sound dentin for all lasers. PMT and AT induced by Nd : YAG>Ho : YAG>Er : YAG for all forms of dentin. Microhardness was increased in sound dentin at PMT. Morphology of crater examined by light microscopy showed Nd : YAG was safe and effective for removing carious dentin and Er: YAG was effective for removing sound dentin. The PMT and AT for YAG lasers are different as a function of dentin type which may be utilized for selective modification and removal of dentin.

• Restorative Dentistry and Endodontics
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• 제39권3호
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• pp.195-200
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• 2014

Objectives: To comparatively evaluate the efficacy of photo-activated disinfection (PAD), calcium hydroxide (CH) and their combination on the treatment outcome of indirect pulp treatment (IPT). Materials and Methods: Institutional ethical clearance and informed consent of the patients were taken. The study was also registered with clinical registry of India. Sixty permanent molars exhibiting deep occlusal carious lesion in patients with the age range of 18 - 22 yr were included. Clinical and radiographic evaluation and set inclusion and exclusion criteria's were followed. Gross caries excavation was accomplished. In group I (n = 20) PAD was applied for sixty seconds. In group II (n = 20), CH was applied to the remaining carious dentin, while in group III (n = 20), PAD application was followed by CH placement. The teeth were permanently restored. They were clinically and radiographically followed-up at 45 day, 6 mon and 12 mon. Relative density of the remaining affected dentin was measured by 'Radiovisiography (RVG) densitometric' analysis. Results: Successful outcome with an increase in radiographic grey values were observed in all three groups. However, on inter-group comparison, this change was not significant (p > 0.05). Conclusions: PAD and CH both have equal disinfection efficacy in the treatment of deep carious dentin. PAD alone is as effective for treatment of deep carious lesion as calcium hydroxide and hence can be used as an alternative to CH. They can be used independently in IPT, since combining both does not offer any additional therapeutic benefits.

• Restorative Dentistry and Endodontics
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• 제25권3호
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• pp.321-337
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• 2000

Dental caries, one of the most frequent dental disease, become larger because it can be thought as a simple disease. Further more, it can progress to unexpected root canal therapy with fabrication of crown that needs reduction of tooth structure. Base is required in a large caries and ZOE, ZPC, glass ionomer are used frequently as base material. They, with restorative material, can affect the longevity of the restoration. In this study, we assume that the mandibular 1st molar has deep class I cavity. So, installing the 3 base material, 3 kinds of fillings were restored over the base as follows; 1) amalgam only, 2) amalgam with ZPC, 3) amalgam with ZOE, 4) amalgam with GI cement, 5) gold inlay with ZPC, 6) gold inlay with GI cement, 7) composite resin only, 8) composite resin with GI cement. After develop the 3-dimensional model for finite element analysis, we observe the distribution of stress and temperature with force of 500N to apical direction at 3 point on occlusal surface and temperature of 55 degree, 15 degree on entire surface. The analyzed results were as follow : 1. Principal stress produced at the interface of base, dentin, cavity wall was smallest in case of using GI cement as base material under the amalgam. 2. Principal stress produced at the interface of base, dentin, cavity wall was smaller in case of using GI cement as a base material than ZPC under gold inlay. 3. Composite resin-filled tooth showed stress distributed over entire tooth structure. In other words, there was little concentration of stress. 4. ZOE was the most effective base material against hot stimuli under the amalgam and GI cement was the next. In case of gold inlay, GI cement was more effective than ZPC. 5. Composite resin has the small coefficient of thermal conductivity. So, composite resin filling is the most effective insulating material.

• Restorative Dentistry and Endodontics
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• 제16권1호
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• pp.106-120
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• 1991

The main purpose of this study was to investigate the possibility of obstruction of dentinal tubules through irradiation of the $CO_2$ laser on the dentin surface. For this study, 104 extracted caries - free premolars and molars were grinded their mesial or distal surface to expose dentin completly. And these specimens were divided into three Groups. Group I : those with their smear layer not removed and Group IT : those with their smear layer removed, were irradiated by the $CO_2$ laser(SPACE LASER - $CO_2$ VEGA 25) at five different energy levels ranging 4 - 20J/$cm^2$, and all specimens were observed with scanning eletron microscope (Hitachi S - 450). Group m was divided into 2 sub - groups: one with smear layer, another one without and those were irradiated with $CO_2$ laser of the same condition as Group I & II. All specimens were immersed in, $37^{\circ}C$, 0.5% methylene blue solution for 48 hours after 100 times of thermocycling at $4^{\circ}C$ and $60^{\circ}C$, and were observed with stereo -light microscope (Olympus SZH - ILLD) to evaluate dye penetration. The following results were obtained; 1. The dentinal tubules were obstructed through laser irradiation. 2. The dentinal tubules were still obstructed after treatment of 10% HCl/2sec., then it was proved that acid resistance of detin surface was also increased. 3. The Group of laser irradiation showed less dye penetration than control Group. 4. The smear layer hardly affected obstruction of the dentinal tubules through laser irradiation.

• 대한소아치과학회지
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• 제36권1호
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• pp.96-101
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• 2009

국소적 치아이형성증(regional odontodysplasia)은 매우 드물게 나타나는 치아의 형성 장애로서 치아 발육이 국소적으로 정지되어 발생하며 이환된 유치와 영구치의 모든 경조직이 발육 부전이나 석회화 부전을 나타내는 질환이다. 하악 보다는 상악에서 호발하는 것으로 알려져 있으며 인종간의 차이는 없고, 여성에서 2배 정도 많이 발생한다. 국소적 치아이형성증의 정확한 원인은 밝혀지지 않았으나, 국소적 혈액 순환 장애나 체성 돌연변이, 바이러스 침투, 치배 감염, 치아 외상, 이상고열, 방사선 조사, 영양 및 대사 장애, 유전 등이 보고되었다. 이환된 치아는 정상치아보다 크기가 작고, 저형성을 보이며, 노란색 또는 황갈색을 나타내고, 거칠고 취약한 치면을 가진다. 방사선학적인 특징은 법랑질이 정상의 경우보다 얇고 치밀하지 못하며, 상아질의 발육부전으로 치수강이 크고, 근관은 넓게 보이며, 치근은 짧고 불명확하게 보인다. 간혹 치관부가 너무 얇고 석회화가 불량하여 방사선사진에 보이지 않을 수도 있다. 이 증례는 연세대학교 치과대학병원 소아치과에 내원한 환아에 관한 증례로, 2세 3개월 남아에서 임상 구강검사 및 방사선사진검사 결과 하악 좌측 1/4 악의 유치열에 발육부전과 석회화부전 소견을 보이는 국소적 치아이형성증으로 진단되어 이를 보고하는 바이다.