The combined effect of light-illuminating direction and enamel rod orientation on color adjustment at the enamel borders of composite restorations.

OBJECTIVES: To investigate the effect of light-illuminating direction (from composite or enamel side) on color adjustment at the coronal and cervical enamel borders in composite restorations. MATERIALS AND METHODS: Forty cylindrical holes (3.0-mm diameters) were prepared in bovine enamel disks (1.0-mm thickness). After application of a one-step self-etch adhesive, one of four resin composites (Estelite Asteria, EA; Estelite Pro, EP; Kalore, KA; Clearfil Majesty ES-2 Premium, MJ) was restored in the holes. After 24-h storage, the colors (L*, C*, or h* values) at the restored enamel disks over a black background were measured in a black box using a CIE XYZ camera, spotted with D65 standard illuminant either from coronal or cervical side at 45°/0° geometry. The color shifting rate was calculated at the coronal and cervical enamel borders of the composite restorations, and analyzed by three-way ANOVA with Dunnett's T3 and t test for post hoc analysis (p < 0.05). RESULTS: The light-illuminating directions significantly affected the L* shifting rate at the cervical enamel border in EP and MJ (p < 0.05), and the C* shifting rate at the coronal enamel border in EA, EP, and MJ (p < 0.05). CONCLUSIONS: The color appearance at the border of the composite restoration was influenced by the light-illuminating direction in conjunction with the enamel rod orientation in the coronal or cervical enamel border. CLINICAL RELEVANCE: The line-of-vision angle would affect the perception of color adaptation at the enamel borders in the composite restorations.

A proposed core curriculum for dental English education in Japan.

BACKGROUND: Globalization of the professions has become a necessity among schools and universities across the world. It has affected the medical and dental professions in terms of curriculum design and student and patient needs. In Japan, where medicine and dentistry are taught mainly in the Japanese language, profession-based courses in English, known as Medical English and Dental English, have been integrated into the existing curriculum among its 83 medical and 29 dental schools. Unfortunately, there is neither a core curriculum nor a model syllabus for these courses. METHODS: This report is based on a survey, two discussion forums, a workshop, and finally, the drafting of a proposed core curriculum for dental English approved by consensus of the participants from each university. RESULTS: The core curriculum covers the theoretical aspects, including dental English terms and oral pathologies; and practical aspects, including blended learning and dentist-patient communication. It is divided into modules and is recommended to be offered for at least two semesters. CONCLUSIONS: The core curriculum is expected to guide curriculum developers in schools where dental English courses are yet to be offered or are still in their early development. It may also serve as a model curriculum to medical and dental schools in countries in Asia, Europe, Africa, and Central and South America, where English is not the medium of instruction.

An investigation into the cognitive flexibility of undergraduate dental hygiene students at two dental schools in Asia.

Background/purpose: Cognitive flexibility is a personality trait, which can influence how effectively a healthcare professional can manage a challenging clinical situation. This study explored the cognitive flexibility of undergraduate dental hygiene students at two universities in Asia to gather baseline information in order to consider whether there was an educational need for pre-clinical students with regards to this personality factor. Materials and methods: Participants were all undergraduate dental hygiene students in the 2022 academic year at Tokyo Medical and Dental University (TMDU; n = 79) and Taipei Medical University (TMU; n = 88). An anonymous questionnaire was distributed, which included questions on demographic information and the Cognitive Flexibility Inventory (CFI). Results: The response rates were 97.5% (TMDU) and 89.8% (TMU). The CFI total scores were 91.77 for TMDU and 95.87 for TMU, and there was no significant difference between the two schools. The Alternatives scores were significantly higher in TMU than TMDU (P = 0.044), but there were no significant differences in the Control scores between the two schools. There were also no significant differences between school years of both universities. Conclusion: The dental hygiene students from both dental schools exhibit moderate cognitive flexibility. The educators in both dental schools may consider whether they should investigate and develop this personality factor further during the undergraduate training of their dental hygiene students.

Critical thinking education for dental schools in Asia: Perceptions of educators.

Teaching competence in critical thinking is an important element of undergraduate dental curricula. The pedagogy for critical thinking education in Asia requires further discussion and neither the current situation nor the possible challenges are widely known from the perspectives of dental educators. Therefore, seven educators from four countries gathered online in the summer of 2021 to share the current situation and possible challenges. All the participants considered "critical thinking" was "important" (43%) or "very important" (57%), however, 86% mentioned that they faced challenges in delivering education in critical thinking. The challenges to delivering critical thinking education were insufficient time in the curriculum and lack of human resources; lack of information on appropriate teaching methods for the student population; and no established methods of assessment. How to teach and assess critical thinking therefore requires more brainstorming, and raising the awareness of educators to implement this education might be necessary.

Perceived stress and career planning awareness of Japanese and Taiwanese undergraduate dental hygiene students.

Background/purpose: Dental hygiene students' stress might be rising with increasing undergraduate study content and expansions in dental hygienists' roles and expectations as society changes. This study explored Japanese and Taiwanese dental hygiene students' perceptions of stress and their idea of career planning. Materials and methods: Participants were second- to fourth-year students in the 2020 academic year at Tokyo Medical and Dental University (TMDU; n = 60) and Taipei Medical University (TMU; n = 62). An anonymous questionnaire was distributed, which included questions on demographic information and career planning, as well as the Perceived Stress Scale-10 (PSS-10) and modified Dental Environment Stress questionnaire (DES). Results: The response rates were 100.0% (TMDU) and 96.8% (TMU). The number of participants who chose dental hygiene as the first program choice (P < 0.001) and wished to work as dental hygienists after graduation (P = 0.018) in TMDU was significantly higher than in TMU. There was no significant difference between the two schools' stress levels in both PSS-10 and DES-26. The factors influencing students who wished to work as dental hygienists after graduation were "clinical year or not" (P = 0.007) in TMDU, and the DES factor included items related to lack of confidence in becoming a successful and competent dental hygienist, expectations, and fear of the future (P = 0.033) in TMU. Conclusion: Both schools' students experienced moderate or relatively low levels of stress. TMDU students had higher stress related to academic studies, while TMU students had slightly higher stress related to future anxiety.

Fostering globally competent dental students through virtual team-working, problem-solving and person-centred multi-disciplinary care planning.

Background/purpose: : Development and acquisition of communication, logical thinking, team-building, critical appraisal, critical thinking and person-centred multi-disciplinary care planning must be considered as skill sets and global core competencies for a dental professional. Therefore, an international online study course to foster undergraduate dental students' skill sets in these areas was established and this study aimed to report the perceptions of participants. Materials and methods: An international online course consisting of three levels pertaining to the school year was delivered to dental undergraduates of Japan and Thailand from September to December in 2021. An online questionnaire survey was conducted to obtain feedback from the participants and assess the implementation of the course. Results: In total, 64 responses were obtained from students who participated in all the assigned online sessions and completed the questionnaire (a response rate of 88%). More than 95% of students from each level felt that the programme increased their motivation to study clinical dentistry, and was beneficial for their future and made them appreciate the importance of participating in international exchange. The ratio of favourable respondents was more than 90% with a 95% confidence interval. Conclusion: Fostering globally competent dental students is important and the acquisition of necessary skill sets could be enhanced through international virtual team-working, problem-solving and person-centred multi-disciplinary care planning activities. These are beneficial for undergraduate dental student training so that they graduate with a broader global perspective and an appreciation of the importance of delivering person-centred culturally sensitive dental care.

Critical thinking disposition among Thai dental students.

OBJECTIVES: Critical thinking is recognized as an essential aspect in the training of healthcare professionals, yet it has not been explicitly applied to dental education in Thailand. Therefore, this research study aimed to survey the status of critical thinking disposition among Thai dental students and examine the correlation between critical thinking disposition and academic performance. METHODS: In 2020, 322 students from a Thai dental school were invited to participate in the study and answer an online questionnaire supplying demographic data and Grade Point Average (GPA), and respond to the California Critical Thinking Disposition Inventory (CCTDI). A one-way analysis of variance and Spearman's correlation were used to analyze the data. RESULTS: Overall, 279 of the 322 participants (86.6%) completed the demographic information and CCTDI. Three subscales were found to be in the ambivalent range: truth-seeking (36.8 ± 6.2), systematicity (39.0 ± 5.5), and maturity of judgment (37.1 ± 5.9). Most of the CCTDI subscale scores did not significantly correlate with GPAs, except for systematicity (r = 0.119, p = 0.047) and confidence in reasoning (r = 0.146, p = 0.015). CONCLUSION: This study examined the strengths and weaknesses of the students' critical thinking dispositions. Their GPAs correlated with two critical thinking disposition subscales; however, the results did not guarantee a correlation with academic outcomes. Pedagogical strategies to develop dental students' critical thinking dispositions need to be further assessed.

Effects of two-year oral health information provision on changes in gingival crevicular fluid in male day-night shift workers.

Background/purpose: Although dental diseases are related to systemic diseases and daily habits and are known to affect the quality of life, little attention has been paid to the importance of oral hygiene in Japanese working-age adults. We, thus, aimed to assess changes in the periodontal condition of working-age adults after providing regular oral health information at their workplace for two years. Materials and methods: Two years of oral health information were provided to workers at four printing companies. The effectiveness thereof was assessed using gingival crevicular fluid (GCF) test results-lactoferrin (Lf), alpha-1-antitrypsin (AT), and aspartate aminotransferase (AST). Questionnaires on health literacy (HL) and dental terminology were also administered to the workers during annual check-ups. Results: The baseline survey participants included were 234 male workers, of which 104 workers followed the same work schedule/day-night shifts and completed the two-year follow-up survey were examined. Providing continuous oral health information with regular updates did not improve participants' self-administered GCF tests (Lf: P = 0.272, AT: P = 0.723, and AST: P = 0.067), and there were no significant changes in HL, perceived symptoms, and use of interdental cleaning tools. Conclusion: Direct oral health education or examination might be necessary for working-age adults to achieve optimum oral conditions, and one-on-one health information provision might not improve their oral condition. A combination of methods to provide oral health promotion must be considered.

Evaluating e-learning on an international scale: An audit of computer simulation learning materials in the field of dentistry.

BACKGROUND/PURPOSE: Global networking and e-learning courses are an effective strategy for sharing educational content and there is potential scope to use e-learning technology in dental education. Therefore, this study aimed to explicate the challenges encountered in international e-learning use and decipher optimum solutions for disseminating course/systems on an international scale. MATERIALS AND METHODS: An e-learning course with four computer-assisted simulation materials developed among international faculties was provided to dental undergraduates at dental schools in Japan and Vietnam in 2020. A post-questionnaire survey plus pre- and post-tests were conducted to obtain learners' feedback and assess the success of the course's implementation. RESULTS: Altogether, 41 students participated, with a response rate of 78.8%. The mean post-test score was significantly higher than that of the pre-test (p < 0.001). Students from both groups felt that e-learning was beneficial, useful for their future, and should be continued. CONCLUSION: This study showed that e-learning/course provision could be achieved at an international level by using a common online system, which is beneficial for students to gain a wider perspective and global dental education. Learners indicated that they learned without any major problems in learning operations. This type of educational material creation and course implementation is extremely important in global networking and dental education in the present era; and communication and cooperation between the faculties was important for course provision. More countries should be included in future studies to ensure that it has global application.

Dental Hygiene Learning Outcomes Obtained Through Computer-Assisted Simulation Modules.

Purpose: Education reflecting current knowledge is required for competent health care providers but the number of educators and/or lecture/clinical contact hours are often limited. The purpose of this study was to evaluate the learning outcomes and practicality of interactive simulation modules developed for a computerized learning system in dental hygiene education.Methods: Twenty-nine Japanese fourth-year dental hygiene undergraduates were given access to five interactive modules, delivered via a learning management system (LMS), for one month. The modules provided virtual clinical settings to take learners through decision-making processes for explaining procedures and treatments, and making appointments in English. Pre- and post-tests and a questionnaire were used to evaluate the knowledge gained and to receive learner's feedback. Participants were classified into two groups (study group and non-study group), based on their use/non-use of modules made available during the five-week period for statistical analysis.Results: Post-test scores were significantly higher in the study group (n = 22) than in the non-study group (n = 6), (p = 0.024). Post-test scores were also significantly higher than the pre-test scores in the study group (p = 0.001). No significant differences in the post- versus pre-test scores were found in the non-study group. The questionnaire response rate of 100% (n = 29) indicated that participants considered the interactive modules, including the system operation, as convenient and beneficial.Conclusion: Modules made available via a LMS for self-study were beneficial for Japanese undergraduate dental hygiene students in the acquisition of knowledge and skills for clinical decision-making in English.

Influence of enamel prism orientations on color shifting at the border of resin composite restorations.

This study aimed to investigate the influence of enamel prism orientations on color adjustment of resin composite restoration. The color measurements (L*, C*, or h* values) at the restored bovine enamel disk (1.0 mm-thick) with resin composite (Estelite Asteria, Estelite Pro, Kalore, Clearfil Majesty) were performed using a CIE XYZ camera (RC500). The color shifting rate and range at the coronal and cervical border were calculated. The coronal border was significantly lower L* and C* color shifting rate than the cervical border (p<0.05). The L* color shifting range was significantly affected by regions in the 3-mm cavity group (p<0.05), but not in the 1-mm cavity group (p>0.05), while the C* color shifting range was not significantly affected by regions (p>0.05). The coronal enamel border with diagonal-cut of enamel prisms would have an advantage for color adjustment of resin composite restorations compared to the cervical border with longitudinal-cut of enamel prisms.

English education for healthcare professionals in Japan.

In a global environment, education for healthcare professionals should include cultivating human resources who have the necessary skills to work in an international arena. This article will review the current status of English education for dental healthcare professionals in Japan. After conducting a literature search using the keywords: English education, Japan, and dental, only a few studies were found that investigated and proposed suggestions for dental professional English education. Even so, these were still in the early stages with outcomes yet to be fully evaluated. Even though English is thought indispensable for global professionals, and that increasing chances for communication skills is necessary, little attention has been addressed to English education for dental professionals or the implementation of such education in the Japanese undergraduate dental curricula. With the current reality of field expansion in dentistry, the need for not only improved English communication skills for Japanese dentists, but also the acquisition of essential expertise, psychomotor, teambuilding, critical thinking, and creative thinking skills in English as well as Japanese, is a definite probability. In order to reach this level of knowledge, further efforts and research would be necessary for the advancement and development of dental professional English education in Japan.

The role of enamel thickness and refractive index on human tooth colour.

OBJECTIVES: To investigate the role of enamel thickness and refractive index (n) on tooth colour. METHODS: The colour and enamel thickness of fifteen extracted human central incisors were determined according to CIELab colour scale using spectrophotometer (Crystaleye) and swept-source optical coherence tomography (SS-OCT), respectively. Subsequently, labial enamel was trimmed by approximately 100µm, and the colour and remaining enamel thickness were investigated again. This cycle was repeated until dentin appeared. Enamel blocks were prepared from the same teeth and their n were obtained using SS-OCT. Multiple regression analysis was performed to reveal any effects of enamel thickness and n on colour difference (ΔE00) and differences in colour parameters with CIELCh and CIELab colour scales. RESULTS: Multiple regression analysis revealed that enamel thickness (p=0.02) and n of enamel (p<0.001) were statistically significant predictors of ΔE00 after complete enamel trimming. The n was also a significant predictor of ΔH' (p=0.01). Enamel thickness and n were not statistically significant predictors of ΔL', ΔC', Δa* and Δb*. CONCLUSIONS: Enamel affected tooth colour, in which n was a statistically significant predictor for tooth colour change. CLINICAL SIGNIFICANCE: Understanding the role of enamel in tooth colour could contribute to development of aesthetic restorative materials that mimic the colour of natural tooth with minimal reduction of the existing enamel.

Effect of enamel margin configuration on color change of resin composite restoration.

This study aimed to investigate the effect of enamel margin configuration on color change of resin composite restoration. Enamel disks of 1.0 mm-thick were sliced from sixty bovine anterior teeth and divided into three groups by margin configuration (non-bevel, 45-degree bevel and 45-degree reverse-bevel). The color measurements (L*C*h* values) at the restored bovine enamel disk with resin composite (Estelite Asteria, Estelite Pro, Kalore, Clearfil Majesty) were performed using a digital camera with CIE XYZ color gamut (RC500). All the resin composite restorations with non-beveled and beveled cavities significantly increased L* values compared with the control composite disks (p<0.05). The bevel preparation increased L* values toward the enamel-composite border with gentle inclination, while the reverse-bevel preparation was significantly lower L* values at the enamel-composite border than the non-bevel preparation (p<0.05). Enamel margin configuration affected color shifting of resin composite restoration and color adjustment of the border.

Evaluation of simulation learning materials use to fill the gap in Japanese dental English education.

Even though English is most frequently the common language when the patient's native language differs from that of a dentist, the opportunities for Japanese undergraduate dental students to learn dental English are now quite limited. The purposes of our study were to investigate: the effectiveness and feasibility of the computer-assisted simulation materials as one solution strategy for dental English education in Japan, and the needs and demands for dental English from the learners' side. Interactive simulation materials for medical interviews in English and clinical cases which were translated to English, were delivered via Learning Management System (LMS) to nineteen trainee residents of dentistry (residents). Evaluation for the materials, learners' knowledge and interests in the contents, and ease of operation were obtained by post-questionnaire (response rates were 100% and 95%, respectively). Both questionnaire-surveys received positive feedback toward the materials, yet 47% answered that they lacked the level of knowledge about contents of the medical interview in English. Results were sufficient to suggest that the residents would like to have the opportunity to study or practice medical interview in English, or English related to dentistry, and that the simulation materials could be one of the solution strategies for opportunity provision.

[A case of asymmetric demyelinating neuropathy in a patient with chronic graft-versus-host disease].

A 47-year-old man, who suffered from acute lymphocytic leukemia at 45 years old and was treated with hematopoietic stem cell transplantation at 46 years old after the induction of complete remission by the standard chemotherapy, developed the symptoms of chronic graft-versus-host disease (cGVHD) such as dry eyes, dry mouth, skin thickening, skin scaling, skin pigmentation and impaired liver function. He was admitted to our hospital because of the acute development of diplopia and weakness of his left upper extremity accompanying with the exacerbation of other symptoms of cGVHD. Neurological examinations revealed the right abducens nerve palsy and asymmetric muscular weakness of the extremities; the proximal part of the left upper extremity and the distal part of the right upper extremity were markedly involved. Neurophysiological studies including magnetic motor root stimulation revealed demyelinating neuropathy specifically involving the motor nerves. On the basis of these findings, a diagnosis of peripheral neuropathy associated with cGVHD was made. Nighteen reports are available on peripheral neuropathy in cGVHD patients, but to date little is known about the pathophysiology of this condition. Most of those patients have been diagnosed as having symmetric demyelinating polyneuropathy, such as Guillain-Barré syndrome or chronic inflammatory demyelinating polyneuropathy. In this study, contrary to previous reports, the asymmetric involvement of motor nerves is noteworthy. Accumulation and further analyses of the cases like the present case are necessary to elucidate the pathogenesis of peripheral neuropathy in cGVHD.

The influence of light intensities irradiated directly and indirectly through resin composite to self-etch adhesives on dentin bonding.

This study was designed to evaluate effects of light-irradiated intensities directly and indirectly through resin composites to one- and two-step self-etch adhesives on dentin bonding. One-step (Clearfil S(3) Bond; TS, Bond Force; BF) or two-step (Clearfil SE Bond; SE) self-etch adhesives was applied to dentin surface. The adhesive agent was light-cured with light-intensity of 350 or 600 mW/cm(2), and then resin composite with different colors (translucent or opaque shade) was filled and light-cured with the same light-intensity as the bonding procedure. After 24 h water storage, bond strengths to dentin were determined using µTBS test. For the 600 and 350 mW/cm(2) groups, translucent shade resin obtained higher µTBS than opaque shade resin. Using SE and BF, the 350 mW/cm(2) group in translucent shade resin was higher µTBS than the 600 mW/cm(2) group in opaque shade resin, while TS showed no different µTBS between them.

Dentin bond durability and water sorption/solubility of one-step self-etch adhesives.

The purpose of this study was to evaluate the dentin bonding durability of three HEMA-containing one-step self-etch adhesives after one-year water storage and to measure the amounts of their water sorption/solubility. OptiBond All-In-One (OP), Bond Force (BF) and Clearfil S³Bond (S³) were applied to the dentin surfaces according to manufacturers' instructions. Bond strengths to dentin were determined using µTBS test after water storage for 24 hours, six months, and one year. In addition, water sorption and solubility of the polymerized adhesives were measured. The µTBS of S³ and OP significantly decreased after one year. On the other hand, for BF there were no significant differences in µTBS between all storage periods. There were significant differences in water sorption and solubility among the adhesives (BF>S³>OP). The initial amounts of water sorption and solubility of the three adhesives did not affect their bonding durability to dentin.