Fracture strength of endocrown maxillary restorations using different preparation designs and materials.

PURPOSE This study investigated the impact of preparation design and material types on fracture strength in maxillary premolars endocrowns after thermodynamic aging. MATERIALS AND METHODS Eighty two-rooted maxillary premolar crowns underwent endodontic treatment (N = 80, n = 10). The teeth were categorized into ten groups (4-mm deep with no intracanal extension lithium disilicate glass ceramic & multilayer zirconia endocrowns (LE0 & ZE0); 4-mm deep with 4-mm intracanal extension in one canal (LE1 & ZE1); 4-mm deep with 2-mm intracanal extensions in both canals (LE2 & ZE2); flat overlays with no endocore (LO & ZO); glass fiber reinforced post & core and crown (LC & ZC)). After cementation, all specimens were subjected to 1500 thermocycles and 1,200,000 chewing cycles with an axial occlusal load of 49 N. A static loading test was performed at a non-axial 45° loading using a universal testing machine and failure modes (Type I: restoration debonding; Type II: restoration fracture; Type III: restoration/tooth complex fracture above bone level; Type IV: restoration/tooth complex fracture below bone level) were evaluated using a stereoscope. Data were ananalzed using 2-way ANOVA and Tukey's tests (alpha = 0.05). RESULTS The endocrowns manufactured from multilayered zirconia and pressed lithium disilicate glass ceramic exhibited a fracture load ranging between 1334 ± 332 N and 756 ± 150 N, with ZC presenting the highest and LE2 the lowest values. The differences were not statistically significant (p > 0.05). CONCLUSION All endocrowns tested in this study performed similar considering the different designs and materials tested. The distribution of fracture modes did not differ significantly depending on the design of the restoration and the type of material used

Quality, effectiveness and outcome of blended learning in dental education during the COVID pandemic: Prospects of a post-pandemic implementation

Abstract: BackgroundBlended learning is growing in popularity particularly following the emergence of COVID-19 pandemic. One of the fields that the pandemic has substantially affected is dental education. Purpose: The aim of this study was to evaluate the quality and effectiveness of the online dental education. Students’ perceptions and experiences of blended learning were also investigated. Methods: A 28-question online survey was designed to gauge students’ perceptions of the effect of blended learning on their academic performance. Results: 314 participants in preclinical and clinical years completed the questionnaire (223 females and 91 males). The majority of students (89%) believed that clinical and practical courses cannot be given by the internet. In terms of students’ opinion in the assessment process, more females (65.8%) preferred traditional exams than males (50.5%) (p < 0.05). Most clinical students (83%) preferred a combination of online and traditional teaching compared to 72% of preclinical students (p < 0.05). Clinical year students were more willing to communicate electronically with their classmates and instructors. The majority of dental students (65%) reported that future dental courses should be blended. Conclusions: In the pandemic era, blended learning, should become the preferred method of education whereby theoretical knowledge is delivered through online tutorials and clinical training is resumed on-site, to ensure competency of dental graduates while maintaining safety of the dental team. Current facilities and course designs should be improved in order to improve students’ experiences with blended learning

Success of 3-Unit Posterior All-Ceramic Inlay-Retained Fixed Dental Prostheses: A Narrative Literature Review

PURPOSE OF REVIEW: This narrative review aimed to offer evidence on 3-unit all-ceramic posterior inlay-retained prostheses (IRFDPs) with an emphasis on material choice and design principles. Clinical trials and in vitro studies were identified using an electronic search in PubMed database. Overall, 16 in vitro publications and 8 clinical trials were included that reported on retainer designs, connector dimensions, and tooth preparation designs and detailed bonding techniques, evaluated replacement of posterior teeth, were clinical studies (follow-up ≥ 1 year), or addressed survival or failure rate, based on in vitro chewing simulator, fracture load, and in vivo technical or biological complications. RECENT FINDINGS: Material properties, restoration design, and adhesive technique showed a high impact on performance of IRFDPs. High-strength zirconia ceramics with intracoronal design bonded to enamel seem to perform well in the posterior region of the mouth. Furthermore, air abrasion at moderate pressure in combination with phosphate-containing resins provides durable bonding to zirconia ceramics. SUMMARY: Despite the advances in ceramic materials, there have been few scientific evidence to support the ideal preparation design that might improve clinical performance and restoration lifetime of 3-unit IRFDPs

Fracture strength of endocrown maxillary restorations using different preparation designs and materials

PURPOSE: This study investigated the impact of preparation design and material types on fracture strength in maxillary premolars endocrowns after thermodynamic aging. MATERIALS AND METHODS: Eighty two-rooted maxillary premolar crowns underwent endodontic treatment (N = 80, n = 10). The teeth were categorized into ten groups (4-mm deep with no intracanal extension lithium disilicate glass ceramic & multilayer zirconia endocrowns (LE0 & ZE0); 4-mm deep with 4-mm intracanal extension in one canal (LE1 & ZE1); 4-mm deep with 2-mm intracanal extensions in both canals (LE2 & ZE2); flat overlays with no endocore (LO & ZO); glass fiber reinforced post & core and crown (LC & ZC)). After cementation, all specimens were subjected to 1500 thermocycles and 1,200,000 chewing cycles with an axial occlusal load of 49 N. A static loading test was performed at a non-axial 45° loading using a universal testing machine and failure modes (Type I: restoration debonding; Type II: restoration fracture; Type III: restoration/tooth complex fracture above bone level; Type IV: restoration/tooth complex fracture below bone level) were evaluated using a stereoscope. Data were ananalzed using 2-way ANOVA and Tukey's tests (alpha = 0.05). RESULTS: The endocrowns manufactured from multilayered zirconia and pressed lithium disilicate glass ceramic exhibited a fracture load ranging between 1334 ± 332 N and 756 ± 150 N, with ZC presenting the highest and LE2 the lowest values. The differences were not statistically significant (p > 0.05). CONCLUSION: All endocrowns tested in this study performed similar considering the different designs and materials tested. The distribution of fracture modes did not differ significantly depending on the design of the restoration and the type of material used

Blended learning in undergraduate dental education: a global pilot study.

To explore the global trends in blended learning in undergraduate dental education during the COVID pandemic and during the recovery phase by engaging with the students and faculty and evaluate the implications for dental education in the post-COVID era. It was a pilot cross-sectional study which employed a convenience sampling technique to recruit representatives of dental faculty and undergraduate students in 80 dental institutions globally. A previously validated questionnaire consisting of a combination of closed and open-ended items was used for data collection. Responses to these online questionnaires were processed and analysed using the R statistical computing environment. A total of 320 dental students and 169 faculty members from 47 different dental institutions participated in the study. Video and Live Online Tutorials were considered to be the most effective method of online learning followed by online question banks by both groups. Significant differences were noted between faculty and students regarding time spent and effectiveness of online teaching and learning, respectively, both before and after the start of COVID. The results highlight the faculty need to engage more closely with the students to address their learning needs. Finally, the participants provided several recommendations regarding the future development of teaching and learning strategies as well as assessments in the post-pandemic era. This is the first study which explores blended learning in dental education with participants from multiple institutions in different regions of the globe. Compared to the faculty, students considered online learning to be less interactive and preferred learning activities and all assessments to be delivered face-to-face. The results underscore the need to adapt teaching practices to suit the learning needs of the students