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Purpose: This study aimed to comparatively evaluate the stress distribution of bones surrounding the implant system to which both titanium and polyetheretherketone (PEEK) abutments are applied using a three-dimensional finite element analysis. Methods: The three-dimensional implant system was designed by the computer-aided design program (CATIA; Dassault Systemes). The discretization process for setting nodes and elements was conducted using the HyperMesh program (Altair), after finishing the design of each structure for the customized abutment implant system. The results of the stress analysis were drawn from the Abaqus program (Dassault Systèmes). This study applied 200 N of vertical load and 100 N of oblique load to the occlusal surface of a mandibular first molar. Results: Under external load application, the PEEK-modeled dental implant showed the highest von Mises stress (VMS). The lowest VMS was observed in the Ti-modeled abutment screws. In all groups, the VMS was observed in the crestal regions or necks of implants. Conclusion: The bones surrounding the implant system to which the PEEK abutment was applied, such as the cortical and trabecular bones, showed stress distribution similar to that of the titanium implant system. This finding suggests that the difference in the abutment materials had no effect on the stress distribution of the bones surrounding implants. However, the PEEK abutments require mechanical and physical properties improved for clinical application, and the clinical application is thought to be limited.

Purpose: The purpose of this study is to analyze the depth according to curing using photocurable resin for dental three-dimensional printing. Methods: A stainless mold with a height of 4 mm was prepared. Ultraviolet (UV) polymerization resin was injected into the mold. Photocuring was then performed for 5 minutes using a photopolymerizer, and the height was measured using a digital measuring instrument (first group). Second, light polymerization was also performed outside the mold for 5 minutes, and the height was measured using a digital measuring instrument. Third, light polymerization was further performed for 5 minutes, and the height was measured using a digital measuring instrument. Statistical analysis was performed with the Kruskal-Wallis test, which is a nonparametric test (α=0.05). Results: The third group had the largest measurement length, whereas the first group had the smallest. However, the difference between groups was not statistically significant (p>0.05). The color of the first group was different from that of the second and third groups. Conclusion: All of the 4-mm-thick photocured specimens had a curing reaction, but the part that was not directly irradiated with UV did not show its original color.

Purpose: This study was conducted to verify the effects of self-esteem and critical thinking disposition on dental laboratory technology students’ field practice stress. Methods: The subjects of the study were 198 dental laboratory technology students with clinical practice experience located in Gyeongsangbuk-do and Gyeongsangnam-do. The collected data were analyzed by t-test, ANOVA, correlation analysis, and linear regression analysis using IBM SPSS Statistics ver. 22.0 (IBM). Results: The average self-esteem, critical thinking disposition, and field practice stress scores were 3.76, 3.50, and 2.40, respectively. There was a significant correlation between self-esteem, critical thinking disposition, and field practice stress. It was found that the higher the self-esteem, the lower was the field practice stress. On the contrary, among the sub-items of critical thinking disposition, when intellectual fairness increased, the field practice stress decreased; however, when healthy skepticism increased, the field practice stress increased. Conclusion: Self-esteem and critical thinking disposition were both found to have a substantial effect on field practice stress. Therefore, various educational programs need to increase self-esteem and cultivate critical thinking skills for a successful field practice and field practice stress relief of laboratory technology students.

Purpose: The purpose of this study was to investigate the types of mouthguards athletes who play contact sports use as well as their perceived discomfort of wearing them in order to analyze the relationship with wearing frequency so as acquire basic data for the development of more user-friendly mouthguards. Methods: The participants, who completed a self-report questionnaire, included 70 contact sports athletes, including high school contact (rugby and boxing) sport department affiliated athletes located in the city of Daejeon. Results: Breathing (p<0.01), fitting (p<0.05), ease of wearing (p<0.01), occlusion (p<0.05), and fatigue in muscles (p<0.05) were positively correlated with wearing frequency. Furthermore, the recognition of the mouthguards was not significantly correlated with wearing frequency. Conclusion: To prevent oral and maxillofacial trauma, multi-directional studies are imperative to develop mouthguards, which are comfortable and cost-efficient.

Purpose: This study sought to identify the factors influencing learning motivation and demotivation in online dental technology students. Methods: A survey was conducted from October 1 to 30, 2021, on 188 dental technology students. The collected data were processed using the IBM SPSS IBM SPSS Statistics ver. 22.0 statistical program (IBM), and frequency, factor, and one-way ANOVA analyses were performed, for which the significance was set at 0.05. Results: It was found that the main online learning motivation factors were the usefulness of the learning content, interest, and confidence in the activities, the relationships with the teachers and friends, the feedback, and learning satisfaction. The factors that reduced the students’ online learning motivation were interaction difficulties, maladaptation to the selfdirected learning environment, the inadequate number of learning activities, and activity difficulty. Conclusion: Based on the identified online class motivation and demotivation factors, better systematic management and increased research are needed to improve the quality of non-face-to-face classes.

Purpose: This study analyzes the difficulty and discrimination of the paper-based test (PBT) and the computer-based test (CBT) according to item response theory, focusing on the National Dental Technician Examination. Methods: A mock test was conducted from September 15 to 23, 2020, and the final 179 (1 out of 180 absentees)people were the subjects of this study. Both frequency analysis and factor analysis were performed. The collected data were analyzed using IBM SPSS Statistics ver. 18.0 (IBM) and jMetrik programs. The significance level was set to 0.05. Results: The difficulty of the mock test was more easily responded to in CBT. It was also predicted that the CBT could better measure the ability of test takers than the PBT could. Conclusion: The difficulty, discrimination, and reliability of the questions were not affected by the examination method through the mock test. The feasibility of a future change to the CBT was confirmed by the National Dental Technician Examination.