• 대한치과보철학회지
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• 제33권2호
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• pp.231-239
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• 1995

When the complete denture is made, the record base for jaw relation is divided into temporary record base and permanent record base. However, The temporary record base include some disadvantages such as, the lackness of intimate contact between model and base, the lackness of retention during the jaw relation registration, When we obtained jaw relation the permanent record bases made from heat curing resin were utilized. We could get several advantages as follows : 1. The permanent record base provided intimate contact between the model and record base. 2. In fabricating occlusal rim on record base, the dimensional change of record base was little because the permanent record base was lesser influenced to thermal change of occlusal rim than the temporary record base. 3. At the stage of jaw relation, the retention of final denture could be early checked. 4. It could be able to get more accurate registration of jaw relation because all procedure were done on the same base during the jaw relation, artificial teeth arrangement, try-in, and final denture construction. 5. Although there was an inconvenience due to double curing procedure, the shrinkage rate in resin polimerization was relatively reduced so that more dimensional stability could be taken.

• 대한치과보철학회지
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• 제28권2호
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• pp.199-215
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• 1990

This study was to analyze the stress distribution of implant and supporting tissue in $Br{\aa}nemark$ osseointegration implant. The analysis has been conducted by using the axisymmetric finite element method and type of model according to crown material. Tests have been performed at 1 kg load on central fossa of crown portion. Each type of model was designed differently according to crown material. 1) Porcelain fused to metal crown(Model A) 2) Composite resin veneered crown(Model B) 3) Acrylic resin veneered crown(Model C) 4) Type III gold crown(Model D) The displacements and stresses of implant and supporting structures were analyzed to investigate the influence of the type of crown material. The results were obtained as follows : 1. Displacement of implant was shown uniformly downward displacement in all models and abutments were observed distally downward displacement. 2. In supporting tissues, stress was concentrated on the crest of compact bone and the spongy bone below implant. 3. The PFM and the type III gold crown showed the largest concentration of stress at the crest of compact bone and the spongy bone below implant, respectively. Acrylic resin artificial teeth and composite resin veneered crown indicated almost the same distribution of stress. 4. The gold screw, the abutment screw and the top of abutment showed the concentration of stress in implants of every model.

• 대한치과보철학회지
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• 제56권3호
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• pp.250-257
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• 2018

현재까지 의치는 전통적인 방법을 이용하여 제작하는 것이 일반적이지만, 최근 디지털 기술의 발달로 이를 이용한 의치 제작 빈도가 증가하는 추세이다. 디지털 방식을 이용하여 의치를 제작하는 방법에는 인상체를 3D 스캔하여 CAD 상에서 인공치를 배열한 뒤 이를 3D 프린팅하여 레진상 총의치를 제작하는 방식과 모델을 3D 스캔 후 CAD를 이용하여 frame-work을 디자인하고 3D 프린팅으로 resin pattern을 제작하여 이를 주조 후 금속상 총의치나 국소의치를 제작하는 방식이 대표적이다. 본 증례에서는 디지털 방식의 의치 제작 방법으로써 전자 서베잉을 이용한 진단과 CAD 프로그램을 이용한 framework 디자인, 그리고 이를 3D 프린팅 후 주조하여 상악 총의치와 하악 국소의치를 제작하였으며, 만족스러운 결과를 얻었기에 이를 보고하고자 한다.

• Imaging Science in Dentistry
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• 제41권4호
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• pp.143-150
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• 2011

Purpose : The aim of this study was to compare the diagnostic accuracy of cone-beam computed tomography (CBCT) images and bitewing images in detection of secondary caries. Materials and Methods : One hundred and twenty proximal slots of Class II cavities were randomly prepared on human premolar and molar teeth, and restored with amalgam (n=60) and composite resin (n=60). Then, artificial secondary caries lesions were randomly created using round steel No. 4 bur. The teeth were radiographed with a conventional bitewing technique and two CBCT systems; Pax-500ECT and Promax 3D. All images were evaluated by five observers. The area under the receiver operating characteristic (ROC) curve ($A_z$) was used to evaluate the diagnostic accuracy. Significant difference was tested using the Friedman test (p value<0.05). Results : The mean $A_z$ values for bitewing, Pax-500ECT, and Promax 3D imaging systems were 0.882, 0.995, and 0.978, respectively. Significant differences were found between the two CBCT systems and film (p=0.007). For CBCT systems, the axial plane showed the greatest $A_z$ value. Conclusion : Based on the design of this study, CBCT images were better than bitewing radiographs in detection of secondary caries.

• 대한치과보철학회지
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• 제37권4호
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• pp.465-473
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• 1999

Bond strength of luting cements to dentin is a critical consideration for success of complete cast crowns. This study was performed to evaluate the relationship between surface characteristics of teeth prepared for complete cast crowns and retention of cemented restorations. Eighty artificial crowns were cast for standardized complete crown tooth preparations accomplished with the use of a special device on recently extracted human teeth. Coarse diamond(#102R, Shofu) and superfine finishing diamond(#SF102R, Shofu) burs of similar shape were used. Crowns in each group were randomly subdivided into few subgroups of 10 for luting cements selected for this study: zinc phosphate cement (FLECK' S), polycarboxylate cement (Poly-F), rein-forced glass ionomer cement (Fuji PLUS). and adhesive resin cement (Panavia 21). Retention was evaluated by measuring the tensile load required to dislodge the artificial crown from tooth preparations with an Instron testing machine, and analysed by one-way ANOVA and Student's t-test. The obtained results were as follows ; 1. When tooth preparation was done with coarse diamond bur, retentive force was diminished in order of Panavia 21 Fuji PLUS, FLECK'S, and Poly-F. Retentive forces showed the significant difference between Fuji PLUS group and FLECK'S group(p<0.001). 2. When tooth preparation was done with superfine diamond bur, retentive force was diminished in order of Fuji PLUS, Panavia 21, FLECK'S, and Poly-F. Retentive forces showed the significant difference between Panavia 21 group and FLECK'S group(p<0.001). 3. Retentive force in coarse tooth surfaces was significantly higher than that in superfine tooth surface with all luting cements(p<0.001), and cement residues were almost retained with-in the cast crown in all groups.

• Restorative Dentistry and Endodontics
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• 제24권4호
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• pp.647-656
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• 1999

The purpose of this study was to investigate the shear bond strength and marginal microleakage of composite to enamel and dentin according to different treatment methods when the applied bonding agent was contaminated by artificial saliva. For the shear bond strength test, the buccal and occlusal surfaces of one hundred twenty molar teeth were ground to expose enamel(n=60) and dentin surfaces(n=60). The specimens were randomly assigned into control and 5 experimental groups with 10 samples in each group. In control group, a bonding system(Scotchbond$^{TM}$ Multi-Purpose plus) and a composite resin(Z-100$^{TM}$) was bonded on the specimens according to manufacture's directions. Experimental groups were subdivided into 5 groups. After polymerization of an adhesive, they were contaminated with at artificial saliva on enamel and dentin surfaces: Experimental group 1 ; artificial saliva was dried with compressed air. Experimental group 2 ; artificial saliva was rinsed with air-water spray and dried. Experimental group 3 ; artificial saliva was rinsed, dried and applied an adhesive. Experimental group 4 ; artificial saliva was rinsed, dried, and then etched using phosphoric acid followed by an adhesive. Experimental group 5, artificial saliva was rinsed, dried, and then etched with phosphoric acid followed by consecutive application of both a primer and an adhesive. Composite resin(Z-100$^{TM}$) was bonded on saliva-treated enamel and dentin surfaces. The shear bond strengths were measured by universal testing machine(AGS-1000 4D, Shimaduzu Co. Japan) with a crosshead speed of 5mm/minute under 50kg load cell. Failure modes of fracture sites were examined under stereomicroscope. The data were analyzed by one-way ANOVA and Tukey's test. For the marginal microleakage test, Class V cavities were prepared on the buccal surfaces of sixty molars. The specimens were divided into control and experimental groups. Cavities in experimental group were contaminated with artificial saliva and those surfaces in each experimental groups received the same treatments as for the shear test. Cavities were filled with Z-100. Specimens were immersed in 0.5% basic fuchsin dye for 24 hours and embedded in transparent acrylic resin and sectioned buccolingually with diamond wheel saw. Four sections were obtained from the one specimen. Marginal microleakages of enamel and dentin were scored under streomicroscope and averaged from four sections. The data were analyzed by Kruskal-Wallis test and Fisher's LSD. The results of this study were as follows. 1. The shear bond strength to enamel showed lower value in experimental group 1(13.20${\pm}$2.94MPa) and experimental group 2(13.20${\pm}$2.94MPa) than in control(20.03${\pm}$4.47MPa), experimental group 4(20.96${\pm}$4.25MPa) and experimental group 5(21.25${\pm}$4.48MPa) (p<0.05). 2. The shear bond strength to dentin showed lower value in experimental group 1(9.35${\pm}$4.11MPa) and experimental group 2(9.83${\pm}$4.11MPa) than in control group(17.86${\pm}$4.03MPa), experimental group 4(15.04${\pm}$3.22MPa) and experimental group 5(14.33${\pm}$3.00MPa) (p<0.05). 3. Both on enamel and dentin surfaces, experimental group 1 and 2 showed many adhesive failures, but control and experimental group 3, 4 and 5 showed mixed and cohesive failures. 4. Enamel marginal microleakage was the highest in experimental group 1 and there was a significant difference in comparison with other groups (p<0.05). 5. Dentin marginal microleakages of experimental group 1 and 2 were higher than those of other groups (p<0.05). This result suggests that treatment methods, re-etching with 35% phosphoric acid followed by re-application of adhesive or repeating all adhesive procedures, will produce good effect on both shear bond strength and microleakage of composite to enamel and dentin if the polymerized bonding agent was contaminated by saliva.

• 대한치과기공학회지
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• 제40권4호
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• pp.217-224
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• 2018

Purpose: The aim of this study was to evaluate accuracy of three type complete mandibular denture of before and after polymerization. Methods: Mandibular edentulous model was selected as the master model. 15 study models were made by Type IV stone. Wax complete mandibular dentures were produced by the denture base and artificial teeth. Before and after curing, STL files were obtained using a blue scanner. By superimposing the digitized complete mandibular denture data(after curing) with the CAD-reference(before curing) three-dimensionally, visual fit-discrepancies were drawn by calculating the root mean square (RMS) and visualized on a color-difference map. Each calculated RMS-value was statistically analyzed by 1-way analysis of variance(ANOVA) (${\alpha}=.05$). Results: Mean(SD) RMS-values was OM group $88.98(6.10){\mu}m$, BM group $82.35(13.46){\mu}m$, BDM group $77.83(9.46){\mu}m$. The results of the 1-way ANOVA showed no statistically significant differences in the RMS values of the Three groups for the material (P > .241). Conclusion : Deformation of artificial teeth position was observed in all groups after resin polymerization. But the values, all group were within the clinically acceptable range. The values of BDM group showed the least deformation than the other two groups.

• 대한치과기공학회지
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• 제3권1호
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• pp.9-16
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• 1981

A comparative study was conducted to evaluate the relationship of investing medium to the amount of vertical occlusal changes and to the differences of surface smoothness during denture construction. Three groups of 20 dentures, 30 sets of upper and lower were fabricated of conventional heatcuring acrylic denture base resin, using silicone-gypsum molding techniques, with or without covering the occlusal surfaces of the teeth by artificial stone and all-gypsum molding techniques. The distance between the two reference points indented by 1/2 round bur on the upper and lower frontal surfaces of each articulator were measured and recorded before processing and again after processing and remounting of each denture on the articulator. The differences between the two recordings indicated the amount of vertical opening during denture processing. The difference of surface smoothness were investigated and determined by 3 observers continual comparing of the two randomly selected dentures with each other, which were seperately selected as pairs from the different two groups of 20. The results obtained were as follows: 1. During resin processing no statistically significant differences of the amount of vertical occlusal changes were detected between any of the two groups of two silicone-gypsum and one allgypsum molding techniques, although the amount of vertical opening was somewhat increased when silicone-gypsum molding technique was used. 2. Surface smoothness of the processed denture was makedly by increased when silicone-gypsum molding technique was used.

• 대한소아치과학회지
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• 제44권1호
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• pp.72-81
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• 2017

본 연구의 목적은 유치 상아질의 복합레진 술식에서 각 단계별로 치면에 인공타액이 오염되었을 때와 이것을 제거하는 방법이 한 단계 자가부식 접착제와 두 단계 산 부식 접착제의 결합강도에 미치는 영향을 비교 분석하는 것이다. 연구 목적을 달성하기 위해, 건전한 유구치 42개를 선정하여 세 종류의 상아질 접착제인 Scotchbond Universal Adhesive(SBU), All-Bond Universal(ABU)과 Prime & Bond NT(PNT)에 따라 3개의 군으로 분류하였다. 이를 다시 각 접착제에서 7개의 하위 그룹으로 나누었다. 대조군인 1군을 제외한 나머지 군은 인공타액으로 오염시킨 군으로 다음과 같이 분류하였다: 2, 3군 - 접착제 도포 전; 4, 5군 - 접착제 중합 전; 6, 7군 - 접착제 중합 후. 인공타액은 수세, 건조(2, 4, 6군)와 건조(3, 5, 7군)로 제거하였다. 처치된 치면에 복합레진(Filtek, Z-350)으로 수복하고 시편을 제작한 후 미세인장 결합강도(Microtensile bond strength, MTBS)를 측정하였다. One-way ANOVA와 Tukey HSD test를 이용해서 통계분석을 실시하였다(p < 0.05). 대조군에서 MTBS의 평균값은 PNT가 ABU와 SBU에 비해 높게 나타났다(p < 0.001). 세 가지 접착제의 각 오염단계에서 수세와 건조를 시행했을 때(2, 4, 6군)가 건조만 시행했을 때(3, 5, 7군)보다 높은 결합강도를 나타내었다. 그리고 접착제 중합 전 단계에서 인공타액의 오염이 발생했을 때(4, 5군)는 대조군에 비해 낮은 MTBS를 보였다(p < 0.001). 전반적으로 두 단계 산 부식 접착제가 한 단계 자가부식 접착제에 비해 높은 MTBS를 보였다. 접착제를 중합하기 전 단계에서 인공타액에 오염되었을 경우에는 접착 강도가 현저히 감소하였고, 수세와 건조 과정으로 접착강도를 회복할 수 없었다.

• 대한치과보철학회지
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• 제60권2호
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• pp.202-210
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• 2022

최근 디지털 치의학의 발달로, Computer-aided design-Computer-aided manufacturing (CAD-CAM)을 이용한 의치 제작이 증가하는 추세이다. CAD 소프트웨어를 통해 디자인된 의치를 제작하는 방식에는 밀링을 이용한 절삭가공방식과 3D 프린팅과 같은 적층가공방식이 있으며, 적층가공방식은 보다 복잡한 구조를 재현하는데 유리하게 사용될 수 있다. 본 증례는 뇌경색으로 인해 신체적 장애를 갖게 된 상·하악 완전무치악 환자에서 제작 기간과 내원 간격을 단축하기 위해 광경화 Stereolithography (SLA) 기반의 3D 프린팅을 이용한 디지털 제작 방식의 양악 총의치 수복 증례이다. 최종인상채득을 위해 기존 임시의치를 디지털 방식으로 복제 및 출력하여 개인트레이로 활용하였고, 부가중합형 실리콘 인상재로 채득한 최종인상체에는 수직고경과 중심위, 상악 전치부의 각도 및 길이에 대한 정보가 포함되었다. 또한 임시의치를 장착하고 촬영한 안면 스캔 데이터를 추가로 획득하여 기공 작업 시 교합평면 결정이나 인공치 배열에 참고할 수 있도록 하였다. 인상체를 3차원 스캔 후 CAD 프로그램을 통해 인공치를 배열하였고, 연마면을 형성하여 의치 디자인을 완성하였다. 시적 의치 및 최종 의치는 FDA 승인을 받은 액체 광경화성 레진을 이용하여 SLA 기반 3D 프린터로 출력하였고, 최종 의치는 적절한 안정과 유지, 지지를 보였으며, 기능적, 심미적으로 만족스러운 결과를 얻을 수 있었다. 최종 의치의 전달까지 3회의 내원 횟수를 필요로 하였으며, 기공시간의 단축으로 내원 간격을 줄임으로써 환자의 만족도를 증진시켰다.