Effect of preparation design and endodontic access on fracture resistance of zirconia overlays in mandibular molars: An in vitro study.

PURPOSE To evaluate the fracture resistance of zirconia overlays, considering various preparation designs and the presence of endodontic access. MATERIALS AND METHODS Ninety translucent zirconia (5Y-PSZ) overlay restorations were divided into six groups (n = 15/group) based on different preparation designs, with and without endodontic access: chamfer margin 4 mm above the gingival level without (group 1) and with endodontic access (group 2); margin 2 mm above the gingival level without (group 3) and with endodontic access (group 4); overlay with no chamfer margin without (group 5) and with endodontic access (group 6). Restorations were bonded to mandibular first molar resin dies, and the groups with endodontic access were sealed with flowable resin composite. All restorations underwent 100,000 cycles of thermal cycling between 5°C and 55°C, followed by loading until fracture. Maximum load and fracture resistance were recorded. ANOVA with Tukey post-hoc tests were used for statistical comparison (α < 0.05). RESULTS Fracture resistance significantly varied among overlay designs with and without endodontic access (p < 0.001), except for the no-margin overlays (groups 5 and 6). Overlays with a 2 mm margin above the gingival margin with endodontic access (group 4) exhibited significantly higher fracture resistance compared to both the 4-mm supragingival (group 2) and no-margin (group 6) designs, even when compared to their respective intact groups (groups 1 and 5). There were no significant differences between the no-margin and 4-mm supragingival overlays. CONCLUSION The more extensive zirconia overlay for mandibular molars is the first choice since the 2 mm margin above the gingival level design withstood considerable loads even after undergoing endodontic access. A no-margin overlay is preferred over the 4-mm supragingival design as it preserves more tooth structure and there was no outcome difference, irrespective of endodontic access. Caution is warranted in interpreting these findings due to the in vitro nature of the study

Dental students’ attitudes and perceptions about intraprofessional collaboration/education

الملخص: أهداف البحث: للتحقيق في مواقف وتصورات طلاب طب الأسنان حول التعاون / التعليم المهني الداخلي (التعليم الداخلي) والتعلم المشترك واستكشاف تأثير التعليم الداخلي على التطوير الشخصي والمهني للطلاب المشاركين. طرق البحث: تم استخدام استبانة مصمم خصيصا في هذه الدراسة المقطعية. تتكون الاستبانة من سبعة عشر سؤالا يستهدف معرفة تصورات الطلاب حول: 1- تفضيل / رأي طلاب طب الأسنان حول التعليم الداخلي؛ 2- خبرة طلاب طب الأسنان حول تأثير التعليم الداخلي على نتائج التعلم والتطوير المهني؛ 3- ملاحظات الطلاب حول أهمية التعليم الداخلي في مختبرات المحاكاة السريرية وإعدادات مكان العمل. قام الطلاب بتقييم كل من العبارات السبعة عشر على مقياس ليكرت من 5 نقاط (النطاق: 1 = لا أوافق بشدة، 5 = أوافق بشدة). النتائج: تم تحليل ما مجموعه 259 استبانة (معدل الاستجابة = 65٪). كان جميع الطلاب على دراية بالتعليم الداخلي في مجال طب الأسنان (متوسط الدرجة = 4.22). فضل الطلاب التعلم التعاوني / المشترك مع زملائهم في الفصل. كان هناك إجماع بين الطلاب حول التأثير الإيجابي للتعليم الداخلي على التعلم المعزز، وتعزيز مهارات الاتصال، وإثراء العلاقات المهنية مع الموظفين الداعمين وكذلك مع المرضى، وتحسين المهارات التحليلية والنفسية الحركية، وفهم المشاكل المعقدة في العيادات، وفهم نقاط القوة والقيود التي تؤدي إلى تحسين الذات وزيادة الكفاءة والإنتاجية. الاستنتاجات: كان للتعليم الداخلي تأثير مقنع وقوي وإيجابي وفقا لتجربة طلاب طب الأسنان المشاركين في الدراسة. يوصى بتصميم منهج موحد ووضع مبادئ توجيهية لـلتعليم الداخلي في مؤسسات طب الأسنان من أجل التفاعل الفعال بين المتعلمين في جميع المراحل. Abstract: Objectives: To investigate dental students’ attitudes and perceptions about intraprofessional collaboration/education (IPC/IPE) and shared learning, and to explore the impact of IPC/IPE on the personal and professional development of participating students. Methods: A custom-designed questionnaire was used in this cross-sectional study. The questionnaire comprised 17 questions targeting to capture the student's perceptions about IPC/IPE using three factors: (1) dental students' preference/opinion about the IPC/IPE; (2) dental students' experience about the impact of IPC/IPE on learning outcomes and professional development; and (3) students' feedback about the significance of IPC/IPE in clinical/clinical simulation labs and workplace setting. The students rated each of the 17 statements on the 5-point Likert scale (range: 1 = strongly disagree to 5 = strongly agree). Results: A total of 259 responses were analysed (response rate = 65%). All students were aware of IPC/IPE in the field of dentistry (mean score = 4.22). The students preferred collaborative/shared learning with their own classmates. There was a consensus among students about the positive impact of IPC/IPE on enhanced learning, enhancement of communication skills, and enrichment of professional relationships with supporting staff as well as with the patients. There was also improved analytical and psychomotor skills, understanding of complex problems in the clinic, and understanding of strengths and limitations leading to self-improvement and increased efficiency and productivity. Conclusion: IPC/IPE had a compelling, powerful, and positive impact according to the experience of the participating dental students. It is recommended that a standardized curriculum be designed and guidelines set for IPC/IPE at dental institutions for effective interactions among students of all stages

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population