• Restorative Dentistry and Endodontics
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• 제43권4호
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• pp.40.1-40.10
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• 2018

Objectives: This study evaluated the microtensile bond strength (${\mu}TBS$) of polymer-ceramic and indirect composite resin with 3 classes of resin cements. Materials and Methods: Two computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated polymer-ceramics (Enamic [ENA; Vita] and Lava Ultimate [LAV; 3M ESPE]) and a laboratory indirect composite resin (Gradia [GRA; GC Corp.]) were equally divided into 6 groups (n = 18) with 3 classes of resin cements: Variolink N (VAR; Vivadent), RelyX U200 (RXU; 3M ESPE), and Panavia F2 (PAN; Kuraray). The ${\mu}TBS$ values were compared between groups by 2-way analysis of variance and the post hoc Tamhane test (${\alpha}=0.05$). Results: Restorative materials and resin cements significantly influenced ${\mu}TBS$ (p < 0.05). In the GRA group, the highest ${\mu}TBS$ was found with RXU ($27.40{\pm}5.39N$) and the lowest with VAR ($13.54{\pm}6.04N$) (p < 0.05). Similar trends were observed in the ENA group. In the LAV group, the highest ${\mu}TBS$ was observed with VAR ($27.45{\pm}5.84N$) and the lowest with PAN ($10.67{\pm}4.37N$) (p < 0.05). PAN had comparable results to those of ENA and GRA, whereas the ${\mu}TBS$ values were significantly lower with LAV (p = 0.001). The highest bond strength of RXU was found with GRA ($27.40{\pm}5.39N$, p = 0.001). PAN showed the lowest ${\mu}TBS$ with LAV ($10.67{\pm}4.37N$; p < 0.001). Conclusions: When applied according to the manufacturers' recommendations, the ${\mu}TBS$ of polymer-ceramic CAD/CAM materials and indirect composites is influenced by the luting cements.

• The Journal of Advanced Prosthodontics
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• 제11권2호
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• pp.95-104
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• 2019

PURPOSE. To evaluate the effect of surface treatments and repair materials on the shear bond strength and to measure the fracture toughness of CAD/CAM provisional restoration materials. MATERIALS AND METHODS. Four CAD/CAM (3D printing: Nextdent C&B and ZMD-1000B Temporary, CAD/CAM resin block: Yamahachi PMMA disk and Huge PMMA block) and four conventional (monometacrylate: Jet and Alike, dimetacrylate: Luxatemp and Protemp 4) materials were selected to fabricate disk-shaped specimens and divided into six groups according to surface treatment (n=10). CAD/CAM materials were repaired with Jet or Luxatemp, while conventional materials were repaired with their own materials. The shear bond strength was measured by using universal testing machine. Ten rectangular column-shaped specimens for each material were fabricated to measure the fracture toughness by single edge v notched beam technique. Statistical analysis was performed by one-way ANOVA. RESULTS. The highest shear bond strength of CAD/CAM materials was achieved by SiC paper + sandblasting. It was also accomplished when repairing 3D printing materials with Luxatemp, and repairing CAD/CAM resin blocks with Jet. Yamahachi PMMA disk showed the highest fracture toughness. Nextdent C&B showed the lowest fracture toughness value but no statistically significant difference from Alike and Luxatemp (P>.05). CONCLUSION. In order to successfully repair the CAD/CAM provisional restoration, mechanical surface treatment and appropriate repair material according to the CAD/CAM material type should be selected. The CAD/CAM provisional materials have proper mechanical properties for clinical use as compared to conventional materials.

• 대한치과보철학회지
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• 제59권3호
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• pp.341-349
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• 2021

디지털 방식을 이용한 교합평가는 종래의 방식인 교합지와 occlusion foil 등에 비해 기록, 비교, 분석 등이 쉽고 간편하며 객관적 이라는 장점이 있다. 이에 본 증례보고에서는 교합평가에 디지털 기술을 활용하고자 단일 전장관 수복이 필요한 환자에서 구강스캐너(i500, Medit, Seoul, Korea)를 이용하여 매 내원시 교합을 평가하였으며, 비교를 위하여 교합지를 이용한 교합관계 확인과 디지털 교합분석장비(Dental prescale II, GC corporation, Tokyo, Japan)를 이용하여 교합관계를 평가하였다. 치료과정에서 구강스캐너를 이용한 방법과 기존의 교합지를 이용한 방법이 유사한 결과를 보여 향후 임상적으로 유용하게 사용될 수 있을 것으로 사료되었다.

• 대한치과보철학회지
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• 제57권4호
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• pp.416-424
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• 2019

임플란트 주위염(peri-implantitis)은 임플란트 치료를 받은 환자의 20%가량에서 발병하며, 시간이 지날수록 유병률이 증가한다. 경도 또는 중등도의 임플란트 주위염은 비수술적 또는 수술적 방법을 통해 치료될 수 있으나 심한 치조골 흡수를 동반한 경우 임플란트 제거(explanation)를 동반한 재건이 요구된다. 임플란트 주위염은 재발 가능성이 높아 치료계획 단계에서부터 임플란트 주위염의 재발을 방지하기 위한 고려가 필요하다. 본 증례는 임플란트 주위염과 만성치주염으로 진단된 환자의 증례로, 다수의 임플란트 제거 및 다수 치아 발치 후 상악은 임플란트 유지 피개의치, 하악은 임플란트 고정성 보철로 전악 수복하였다. 임플란트 주위염의 재발을 예방하기 위한 수술적, 보철적 방법을 통해 성공적으로 수복하였기에 이를 보고하고자 한다.

• 대한치과기공학회지
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• 제42권4호
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• pp.326-333
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• 2020

Purpose: The purpose of this study was to evaluate the effects of various zirconia surface treatment methods on shear bond strength with resin cements. Methods: We prepared 120 cylindrical zirconia specimens (⌀10 mm×10 mm) using computer-aided design/computer-aided manufacturing (CAD/CAM). Each specimen was randomly subjected to one of four surface treatment conditions: (1) no treatment (control), (2) airborne-particle abrasion with 50 ㎛ of Al2O3 (A50), (3) airborne-particle abrasion with 125 ㎛ of Al2O3 (A125), and (4) ZrO2 slurry (ZA). Using a polytetrafluoroethylene mold (⌀6 mm×3 mm), we applied three resin cements (Panavia F 2.0, Super-Bond C&B, and Variolink N) to each specimen. The shear bond strength tests were performed in a universal testing machine. The surfaces of representative specimens of each group were evaluated under scanning electron microscope. We used one-way analysis of variance (ANOVA), two-way ANOVA, and post hoc Tukey honest significant difference test to analyze the data. Results: In the surface treatment method, the A50 group showed the highest bond strength, followed by A125, ZA, and control groups; however, no significant difference was observed between A50 and A125, A125 and ZA, and ZA and control (p>0.05). Among the resin cements, Super-Bond C&B showed the highest shear bond strength, followed by Panavia F 2.0 and Variolink N (p<0.05). Conclusion: Within the limitations of this study, application of airborne-particle abrasion and ZrO2 slurry improved the shear bond strength of resin cement on zirconia.

• The Journal of Advanced Prosthodontics
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• 제12권6호
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• pp.376-382
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• 2020

PURPOSE. To determine the shear bond strengths of different denture base resins to different types of prefabricated teeth (acrylic, nanohybrid composite, and cross-linked) and denture teeth produced by computer-aided design/computer-aided manufacturing (CAD/CAM) technology. MATERIALS AND METHODS. Prefabricated teeth and CAD/CAM (milled) denture teeth were divided into 10 groups and bonded to different denture base materials. Groups 1-3 comprised of different types of prefabricated teeth and cold-polymerized denture base resin; groups 4-6 comprised of different types of prefabricated teeth and heat-polymerized denture base resin; groups 7-9 comprised of different types of prefabricated teeth and CAD/CAM (milled) denture base resin; and group 10 comprised of milled denture teeth produced by CAD/CAM technology and CAD/CAM (milled) denture base resin. A universal testing machine was used to evaluate the shear bond strength for all specimens. One-way ANOVA and Tukey post-hoc test were used for analyzing the data (α=.05). RESULTS. The shear bond strengths of different groups ranged from 3.37 ± 2.14 MPa to 18.10 ± 2.68 MPa. Statistical analysis showed significant differences among the tested groups (P<.0001). Among different polymerization methods, the lowest values were determined in cold-polymerized resin.There was no significant difference between the shear bond strength values of heat-polymerized and CAD/CAM (milled) denture base resins. CONCLUSION. Different combinations of materials for removable denture base and denture teeth can affect their bond strength. Cold-polymerized resin should be avoided for attaching prefabricated teeth to a denture base. CAD/CAM (milled) and heat-polymerized denture base resins bonded to different types of prefabricated teeth show similar shear bond strength values.

• 한국콘텐츠학회논문지
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• 제21권5호
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• pp.996-1003
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• 2021

연구의 목적은 치과용 스캐너의 반복측정 안정성 비교를 통해 영향을 미치는 스캐너의 요소를 평가하는 것이다. 연구 목적을 달성하고자 청색광을 사용하는 I사의 스캐너와 광학 방식을 사용하는 Z사의 스캐너 그리고 백색광을 사용하는 D사의 스캐너를 본 연구의 반복측정 안정성 연구에 사용하였다. 측정 결과는 root mean square (RMS)로 계산하였고 one-way ANOVA 통계기법을 적용하여 유의수준을 확인하였다(𝛼=.05). 통계분석 결과 가장 큰 RMS 값을 가지는 스캐너는 Z-opt 그룹으로 38.2 ㎛이었다. 다음으로는 D-white가 35.2 ㎛로 나타났고, 가장 RMS 값이 적은 그룹은 I-blue 그룹으로 34.1 ㎛이었다. 각 그룹간에 RMS 평균을 비교한 결과는 유의하지 않은 것으로 나타났다(p>.05). 이 결과로부터 청색광, 백색광 그리고 광학 방식의 스캐너에서는 반복측정 안정성에서 청색광의 오차가 가장 낮은 것으로 나타났으나 통계적 유의성은 없었다. 연구결과 임상적 허용 가능하다는 것이 본 연구의 결론이다.

• 대한치과보철학회지
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• 제60권1호
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• pp.80-90
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• 2022

디지털 치의학이 발전함에 따라 치과 치료 방식도 다양하게 변화하고 있다. 본 증례에서는 구치부의 병적인 마모로 수직 고경 소실을 보이는 환자에서 적절한 수직 고경을 설정한 후, 디지털 기술을 이용하여 최종 보철물을 사전에 디자인하였다. 이를 바탕으로 치질을 최대로 보존할 수 있도록 치아 삭제량을 계산하였으며, 구내에서 치아 삭제량을 나타내줄 수 있는 가이드를 디자인하였다. 본 가이드를 이용함으로써 복잡한 다수 치아의 삭제가 편리했으며 보다 정확하고 빠른 치아 형성이 가능하였다. 이후 이중 스캔으로 임시 보철물의 정보를 반영하여 전악 지르코니아 크라운으로 최종 보철물을 제작하였다. 디지털 기술을 이용하여 전악 수복 증례의 술 전 계획부터 최종 보철물 장착까지의 복잡한 과정을 빠르고 간편하게 해결할 수 있어, 환자와 술자가 모두 만족할 수 있었다.

• 대한치과교정학회지
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• 제53권1호
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• pp.45-53
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• 2023

Objective: This study aimed to evaluate the shear bond strength (SBS) of orthodontic brackets bonded to three-dimensionally (3D)-printed materials after various surface treatments and artificial aging compared with that bonded to computer-aided design/computer-aided manufacturing (CAD-CAM) polymethyl methacrylate (PMMA)-milled materials. Methods: Eighty cylindrical specimens were 3D printed and divided into the following four subgroups (n = 20 each) according to the surface treatment and artificial aging procedure. Group A, sandblasted with 50 ㎛ aluminum oxide particles (SA) and aging; group B, sandblasted with 30 ㎛ silica-coated alumina particles (CO) and aging; group C, SA without aging; and group D, CO without aging. For the control group, 20 CAD-CAM PMMA-milled cylindrical specimens were sandblasted with SA and aged. The SBS was measured using a universal testing machine (0.25 mm/min), examined at ×2.5 magnification for failure mode classification, and statistically analyzed (p = 0.05). Results: The retention obtained with the 3D-printed materials (groups A-D) was higher than that obtained with the PMMA-milled materials (control group). However, no significant difference was found between the study and control groups, except for group C (SA without aging), which showed significantly higher retention than the control group (PMMA-SA and thermocycling) (p = 0.037). Study groups A-D predominantly exhibited a cohesive specimen mode, indicating specimen fracture. Conclusions: Orthodontic brackets bonded to 3D-printed materials exhibit acceptable bonding strengths. However, 3D-printed materials are prone to cohesive failure, which may result in crown fractures.

• 한국치위생학회지
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• 제22권6호
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• pp.467-475
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• 2022

Objectives: This study aimed to understand the definitions, types, and principles of computer-aided design/computer-aided manufacturing (CAD/CAM) and scanners due to the introduction of digital workflows. Methods: This study was based on information from the government's law and articles published in academic journals. Results: CAD/CAM is a technology that measures the shape three-dimensionally, saves it as data, designs it into the desired shape, and processes the product. Scanners, which are classified as intraoral and extraoral scanners, measure teeth and the intraoral environment three-dimensionally and convert them into three-dimensional (3D). A 3D printer is a machine that creates a 3D object by layering materials based on a 3D drawing. It can be classified into four types according to the method: extrusion, powder bonding, lamination, and photopolymerization methods. The most used 3D printer methods in dentistry are stereolithograhpy and digital light processing, and they are widely used in prosthetic, surgical, and orthodontic fields. Conclusions: As the dental system is digitized, it is expected that the government will classify the dental hygienist scope of work and the universities will reflect the curriculum; it is necessary to develop excellent dental hygienists, diversify the educational pathways, and establish policies to meet the needs of the increasing number of patients.