Performance of universal adhesives on bonding to leucite-reinforced ceramic

KIM RYAN JIN YOUNG(김진영),우정수,이인복,예영아,황진윤,서덕규 한국생체재료학회 2015 생체재료학회지 Vol.19 No.2

Background: This study aimed to investigate the microshear bond strength of universal bonding adhesives to leucite-reinforced glass-ceramic. Methods: Leucite-reinforced glass-ceramic blocks were polished and etched with 9.5% hydrofluoric acid for 1 min. The specimens were assigned to one of four groups based on their surface conditioning (n = 16): 1) NC: negative control with no further treatment; 2) SBU: Single Bond Universal (3M ESPE); 3) ABU: ALL-BOND Universal (Bisco); and 4) PC: RelyX Ceramic Primer and Adper Scotchbond Multi-Purpose Adhesive (3M ESPE) as a positive control. RelyX Ultimate resin cement (3M ESPE) was placed on the pretreated ceramic and was light cured. Eight specimens from each group were stored in water for 24 h, and the remaining eight specimens were thermocycled 10,000 times prior to microshear bond strength evaluation. The fractured surfaces were examined by stereomicroscopy and scanning electron microscopy (SEM). Results: After water storage and thermocycling, the microshear bond strength values decreased in the order of PC > SBU and ABU > NC (P < 0.05). Thermocycling significantly reduced the microshear bond strength, regardless of the surface conditioning used (P < 0.05). Cohesive failure in the ceramic and mixed failure in the ceramic and resin cement were observed in the fractured specimens. The percentage of specimens with cohesive failure after 24 h of water storage was: NC (50%), SBU (75%), ABU (75%), and PC (87%). After thermocycling, the percentage of cohesive failure in NC decreased to 25%; however, yet the percentages of the other groups remained the same. Conclusions: Although the bond strength between resin and hydrofluoric acid-etched glass ceramic was improved when universal adhesives were used, conventional surface conditioning using a separate silane and adhesive is preferable to a simplified procedure that uses only a universal adhesive for cementation of leucite-reinforced glass-ceramic.

Accuracy of Surgical Robot System Compared to Surgical Guide for Dental Implant Placement: A Pilot Study

Xun Jin,KIM RYAN JIN YOUNG(김진영),박지만,정의원,차재국,심준성,허성주 대한구강악안면임플란트학회 2022 대한구강악안면임프란트학회지 Vol.26 No.1

Purpose: This study aimed to evaluate the tracking accuracy of a robot-guided implant surgery system and compare the spatial accuracy of robot-assisted implant surgery with that of static stentguided implant surgery for implant placement. Materials and Methods: The tracking accuracy of the robot system was evaluated by measuring the discrepancy between the robot arm and actual programmed position. Dental implants were placed on 3D printed human phantom models using static stent-guided and robot-assisted surgeries. The top, apex, angular, and depth deviations of the placed implant positions were measured relative to the planned position, and the values were compared between the robot and surgical guide groups. The results were analyzed using the Mann-Whitney U test (α = .05). Results: The tracking accuracy of the robot system showed a linear deviation of 0.13 ± 0.04 mm and an angular deviation of 0.77 ± 0.02° at the drill tip. Deviations at the top and apex of the implants were 0.61 ± 0.29 mm and 0.50 ± 0.14 mm in the robot group and of 0.49 ± 0.39 mm and 0.72 ± 0.39 mm in the surgical guide group, respectively. Angular and depth deviations were of 2.38 ± 0.62° and 0.17 ± 0.12 mm, respectively, in the robot group, and of 3.16 ± 2.36° and 0.15 ± 0.11 mm, respectively, in the surgical guide group. No statistically significant differences were found between the robotic and surgical guide groups (p > .05). Conclusion: The accuracy in implant placement using robot-assisted implant surgery was comparable to that of static-guided surgery. Robot-assisted implant surgery and static-guided surgery tended to result in minor deviations at the apex and top of the implants, respectively.

Education satisfaction and self-assessment of competency among new general dentists in Korea

지영아,권호범,KIM RYAN JIN YOUNG(김진영),백승호 대한치과의사협회 2019 대한치과의사협회지 Vol.57 No.9

Dental education is gradually transitioning to competency-based education system, which aims to help dentists achieve certain core competencies by means of various systems, such as curriculum accreditation. This study examined satisfaction with dental school education and the differences in the perceived importance and self-assessment of competencies among general dentists, in an attempt to propose a desirable direction for dental education. A questionnaire was administered to new general dentists who graduated from a dental school within the past 10 years. The results of the survey were analyzed using the Importance-Performance Analysis to understand differences in dentists’ perceptions. Overall satisfaction with education was low in terms of the curriculum’s relevance to actual practice and its capacity for cultivating required competencies. Furthermore, many of the respondents strongly perceived the need to improve dental education. Additional investigations into the satisfaction with education showed no difference. Among the seven key competency domains, dentists perceived Health Promotion to be important and also assessed themselves as having high competence. However, regarding the perceived importance of the remaining domains, self-assessment of competence was low for Professionalism, Communication & Interpersonal Skills, Knowledge Base, Information Handling & Critical Thinking, Clinical Information Gathering, Diagnosis & Treatment Planning, and Establishment & Maintenance of Oral Health. The results of this study suggest that a competency-based education model should be developed and incorporated into dental education to set performance standards and to promote systematic self-assessment in order to foster the development of competence in dental students.

Effect of 3D print orientation and layer thickness on the accuracy of printed models by DLP and SLA printers

Yung-Soo Kim(김영수),Ji-Chang Song(송지창),Seung-Ho Baek(백승호),Ryan Jin Young Kim(김진영) 대한치과재료학회 2022 대한치과재료학회지 Vol.49 No.1

The aim of this study was to evaluate the influence of print layer thickness and orientation of two 3D printers on the trueness of printed models. Two different models (cube and tooth form models with class II cavity) were printed with a DLP printer (IMC, Carima) and an SLA printer (Form 3, Formlabs) with different layer thickness and printing orientation (n=12). The printed models were scanned to obtain STL datasets. Trueness of the printed models relative to the reference dataset was obtained using the superimposition technique. The surface of the 3D printed models was evaluated by SEM. One-way ANOVA and Tukey post hoc were performed. For the cube model, the overall mean trueness values were lowest by the DLP printer at 0-degree orientation in 50 μm layer thickness (20.49 μm), while the highest deviation was observed with the SLA printer at 45-degree orientation in 100 μm layer thickness (61.03 μm) (p<0.001). For the tooth-shaped model, the lowest deviation was observed with the SLA printer at 0-degree orientation in 50 μm layer thickness (25.63 μm), while the highest deviation was found with the DLP printer at 45-degree in 100 μm layer thickness (47.56 μm) (p<0.001). In SEM image, the SLA printer exhibited a relatively smoother surface compared to the DLP printer. In conclusion, the trueness was affected by the type of 3D printer, the geometry of the printing model, the thickness of the printing layer, and printing orientation for each printer.

레진강화형 글래스아이오노머 바니쉬를 이용한 상아세관의 폐쇄 평가

김민호(Min-Ho Kim),김진영(Ryan Jin-Young Kim),임범순(Bum-Soon Lim),최낙삼(Nak-SamChoi),이인복(In-Bog Lee) 대한치과재료학회 2015 대한치과재료학회지 Vol.42 No.1

The purpose of this study was to compare the occlusive effect of a resin-modified glass ionomer (RMGI) varnish and an oxalate-based desensitizing agent on exposed dentin by evaluating the flow dynamic of dentinal fluid and SEM evaluation of the dentin surface after treatment. Sixteen caries- and restoration-free extracted molars were fixed to slide glasses after horizontally sectioning the roots at 5 mm below the cemento-enamel junction (CEJ). The prepared specimen was connected to a fluid flow measuring device (nano-Flow), and verified no fluid leakage. A V-shaped cavity was prepared at the CEJ to expose the dentin surface, which was then acid-etched, washed, and blot dried. The surface was treated either with an RMGI (Clinpro XT varnish) or an oxalate-based desensitizing agent (SuperSeal) (n=8). A real-time fluid flow was measured throughout the procedures. The fluid flow rates before and after each treatment were evaluated, and the surfaces of the treated dentinal tubules were also examined with SEM. A significant reduction in the rate of fluid flow was observed after treatment in both groups (p<0.05). Clinpro XT varnish exhibited a greater reduction in the fluid flow rate than SuperSeal (p<0.05). SEM evaluation revealed that the size of dentinal tubules was reduced as a result of the deposition of RMGI and oxalate crystals in Clinpro XT varnish and SuperSeal, respectively. Both agents reduced the fluid flow rate, with Clinpro XT varnish being more effective.

한국의 치의학교육 학제에 관한 연구 II: 통합 학제의 필요성

길윤민 ( Yoon Min Gil ),이지현 ( Jihyun Lee ),권호범 ( Ho-beom Kwon ),김선영 ( Sun-young Kim ),김진영 ( Ryan Jin Young Kim ),박신영 ( Shin-young Park ),송영하 ( Youngha Song ),정신혜 ( Shin Hye Chung ),지영아 ( Young-a Ji ) 대한예방치과·구강보건학회 2021 大韓口腔保健學會誌 Vol.45 No.3

Objectives: With the rapid changes in society, there are more arguments for redefining dental education system. This study aimed to review and analyze the problems in the current dental education system in Korea and then propose an integrated education system based on those findings. Methods: A narrative review of the problems confronting the dental education system in Korea was carried out. Accordingly, full-text screening and specialists’ discussions were extracted from the review. The purpose of the review was to summarize the strengths and weaknesses of Korean dental education systems to offer perspectives on an integrated education system in accordance with the specialists’ opinions. Results: The results revealed that the problems of the current dental education system were identified in clinical education, basic science, and humanities and social sciences. Dental schools should provide clinical education so that dental students can be exposed to the clinical environment at an early stage and perform patient-based clinical practice. It is also imperative to encourage participation in research programs to train dental scientists, as well as to reflect on courses that can adapt to changes brought about by new technologies. It is recommended that education opportunities for integrated humanities and social sciences be provided. Conclusions: It will be critical in the future for dental schools to embrace a flexible education system from various perspectives. It is vital that dental schools play a role in developing students’ critical thinking, problem-solving, and decision-making skills. Finally, as part of an integrated education system, an improvement program should be devised.