A Comparative Evaluation of Flexural and Impact Strength of Polymethyl Methacrylate (PMMA) Reinforced With Graphene and Multi-Walled Carbon Nanotubes: An In Vitro Study.

Background and objective Low flexural strength (FS) and impact strength (IS) are major drawbacks in removable prostheses made from polymethyl methacrylate (PMMA). Attempts to enhance the strength and longevity of these prostheses have been of keen interest among researchers. Nanofillers are new and advanced reinforcements that can chemically modify PMMA. Graphene and multi-walled carbon nanotubes (MWCNTs) were used in this study to evaluate FS and IS when added to polymer and monomer individually. Method Four groups were created based on the addition of nanofillers: no nanofillers - control; 0.5% by weight of graphene; 0.5% by weight of MWCNT; and 0.25% by weight of both. These groups were further subdivided into two according to the nanofiller being added to polymer and monomer each. The samples were then subjected to a 3-point bending test to assess FS, and an Izod impact tester was used to test IS. Results Decreased FS and FS were seen in all groups with the addition of nanofillers in the polymer (p<0.001). With the addition of nanofillers in monomer, increased FS and IS were seen in groups with MWCNTs whereas a decrease was seen with the addition of graphene (p<0.001). Conclusion Nanofillers should be added to the monomer of heat-cure PMMA instead of polymer; 0.5% by weight of MWCNT has shown the highest FS and IS when added to the monomer.

Comparative Analysis of Three Different Impression Techniques for Impression Defects and Dimensional Accuracy Using a Digital Intraoral Scanner for Fixed Partial Dentures: An In Vivo Study.

AIM: To evaluate the impression defects and compare the dimensional accuracy of three different impression techniques (single-step, two-step without spacer, two-step with spacer) for fixed partial dentures using a digital intraoral scanner in the anterior maxillary region. MATERIALS AND METHODS: Thirty subjects, above the age of 18 years with maxillary central/lateral incisor requiring fixed prostheses were selected according to the inclusion and exclusion criteria. The impressions were rated and evaluated using Heine C2.3K Binocular loupes (Heine Ltd., Dover, NH, USA). An intraoral scanner and digital vernier calipers were used to study and compare the dimensional accuracy of all three impression techniques.  Results: Statistical analysis using the chi-square test revealed that the single-step double mix technique showed the least number of defects (40%), followed by the two-step without spacer (56.7%) and then the two-step with spacer (80%) impression techniques. Using Kruskal Wallis and Mann Whitney U test for dimensional accuracy, it was found that the two-step with spacer impression technique was closer to the control group (intraoral scanner) followed by the two-step without spacer and then the single-step double mix impression techniques. CONCLUSION: All three impression techniques showed the presence of impression defects, mainly voids and bubbles. The single-step double mix and two-step without spacer techniques had more favourable outcomes compared to the two-step with spacer impression technique. The two-step with spacer impression technique was dimensionally more accurate compared to the two-step without spacer and single-step double mix techniques for fixed partial dentures.

Assessment of digital literacy and use of smart phones among Central Indian dental students.

OBJECTIVES: Education has largely been digitalized. More so, for professional education, keeping updated in this fast paced world has become a necessary requisite and dentistry has not been left untouched. This cross sectional questionnaire based study aimed to assess the digital literacy and smartphone usage amongst the 260 Central Indian dental students including their perspicacity about smartphone/internet usage for learning purposes. The students' attitude for implementation of digital technology in study programs/education system was also evaluated. METHODS: The questionnaire was distributed among total 260 dental students from different dental institutes of Central India. The data was collected and analyzed using SPSS software. RESULTS: Out of 260 students, 250 were internet users, out of which 56% had internet access all time. 94.23% students owned a smartphone. 46.53% (114/245) students had some app related to the dentistry in their smartphone device. The commonest site for surfing related to knowledge seeking was google scholar (72%) followed by Pubmed and others. Nearly 80% dental students believed that social media helps them in their professional course studies. Post graduate students showed statistitically significant difference from undergraduates and interns in terms of knowledge of keywords, dental apps and reading research journals. 89.23% students were keen for implementation of e-learning in their curriculum. CONCLUSION: This study reflects willingness of dental students to adopt digital revolution in dental education which in turn may present an opportunity for educators and policy makers to modify educational methods and thereby advance student's current learning approaches.