BACKGROUND: E-learning is increasingly used during the COVID-19 pandemic, however the impact of this change on students is not known. This study aimed to evaluate perception and satisfaction of health sciences students towards E-learning during the COVID-19 lockdown. METHODS: A structured questionnaire was distributed to 2000 health care students either through email or social media platforms. The questionnaire was divided into two sections: the first section addressed demographic information such as age, education level, course of study, number of lectures attended and country. The second section gathered information on perception and satisfaction of students using 13 close-ended questions. Frequencies and percentages were assessed for demographic data, perception and satisfaction level of students. The paired sample t-test, independent t test and Spearman correlation were applied to evaluate statistical significance between different variables of the study. A p-value of <0.05 was considered significant. RESULTS: Data from 1255 participants were included at a response rate of 66.4%. More than one third (37%) of the students took 25 or more online E-learning sessions and 47% preferred Zoom as an online platform. Participants belonged to 11 countries from developed and developing nations. 41% reported interference of E-learning due to network problems. 60% considered that clinical and practical skills are best learned in clinics and laboratories. More than one third of the students preferred classroom teaching and 34% of the students did not feel confident enough to take exit exams after E-learning sessions. CONCLUSION: E-learning satisfaction levels were better among developed countries (7.34) compared to developing countries (5.82). The majority of participants agreed that E-learning was satisfactory in acquiring knowledge, however not effective in acquiring clinical and technical skills. As the COVID-19 lockdown eases, there is a need for improvement in the methods employed in E-learning and more blended learning among healthcare students is recommended.

An experimental adhesive incorporated with different nano-hydroxyapatite (n-HA) particle concentrations was synthesized and analyzed for dentin interaction, micro-tensile bond strength (μTBS), and degree of conversion (DC). n-HA powder (5 wt % and 10 wt %) were added in adhesive to yield three groups; gp-1: control experimental adhesive (CEA, 0 wt % HA), gp-2: 5 wt % n-HA (HAA-5%), and gp-3: 10 wt % n-HA (HAA-10%). The morphology of n-HA spheres was evaluated using Scanning Electron Microscopy (SEM). Their interaction in the adhesives was identified with SEM, Energy-Dispersive X-ray (EDX), and Micro-Raman spectroscopy. Teeth were sectioned, divided in study groups, and assessed for μTBS and failure mode. Employing Fourier Transform-Infrared (FTIR) spectroscopy, the DC of the adhesives was assessed. EDX mapping revealed the occurrence of oxygen, calcium, and phosphorus in the HAA-5% and HAA-10% groups. HAA-5% had the greatest μTBS values followed by HAA-10%. The presence of apatite was shown by FTIR spectra and Micro-Raman demonstrated phosphate and carbonate groups for n-HA spheres. The highest DC was observed for the CEA group followed by HAA-5%. n-HA spheres exhibited dentin interaction and formed a hybrid layer with resin tags. HAA-5% demonstrated superior μTBS compared with HAA-10% and control adhesive. The DC for HAA-5% was comparable to control adhesive.

Background Studies evaluating and comparing clinical and radiographic peri‐implant indices around narrow diameter implants (NDIs; <3.3 mm) and regular diameter implants (RDIs) in type‐2 diabetes mellitus (T2DM) and non‐diabetic individuals are deficient. Objective To estimate and compare the clinical and radiographic indices around NDIs and RDIs placed in T2DM and non‐diabetic patients. Materials and Methods Eighty‐six patients requiring implant surgery in the posterior mandible were divided into two groups (42 T2DM and 44 non‐diabetic individuals). Patients were further categorized into two subgroups on the basis of diameter of implants: (1) patients with NDIs (3.3 mm ø) and (2) patients with RDIs (4.1 mm ø). Clinical indices evaluating plaque index (PI), bleeding on probing (BOP), probing depth (PD), and crestal bone levels (CBL) were recorded around all dental implants at 18 and 36 months follow up. Serum hemoglobin A1c (HbA1c) test was carried out for both groups to assess the profile of glycosylated hemoglobin at baseline, 18 and 36 months of follow up. Results The mean age of patients in T2DM group and non‐diabetic group was 45.2 and 41.6 years, respectively. At 18 and 36 months follow up, mean HbA1c levels were 6.5% and 4.5% and 6.7% and 4.5% in T2DM and non‐diabetic individuals, respectively. A statistically significant reduction in mean HbA1c levels from the baseline to respective follow‐up periods were seen in T2DM patients. There was no statistically significant difference in the overall mean scores of PI, BOP, PD, and CBL around NDIs and RDIs among T2DM and non‐diabetic patients at 18 and 36 months of follow up. Conclusion NDIs show reliable clinical stability and radiographic bone levels as RDIs placed in T2DM and non‐diabetic individuals, provided oral hygiene and glycemic status are strictly maintained.

The study aimed to evaluate the effect of graphene oxide (GO) nano-filler content in experimental dental adhesive on its degree of conversion (DC), microtensile bond strength (μTBS) and structural reliability, using Fourier transform infrared spectroscopy (FTIR), Micro-Raman spectroscopy and Scanning electron microscopy (SEM). A resin adhesive was fabricated (control adhesive - CA) and fabricated GO nano-particles were added at 0.5% and 2.0% (m/m) to produce adhesives GOA1 and GOA2 respectively. One hundred and two teeth (specimens) were prepared for dentin exposure and conditioned with 36% phosphoric acid. Specimens in each group (n = 34) were treated with formulated adhesives (CA, GOA1 & GOA2) and photo-polymerized for 20 s followed by composite build up. Sixty specimens were used for μTBS testing in the adhesive groups (CA, GOA1 & GOA2), with half exposed to thermocycling (TC) whereas the remaining half (n = 10) stored in distilled water. Seven specimens each were assessed using SEM and Micro-Raman spectroscopy, in each adhesive group (n = 7). DC for the adhesives was assessed using FTIR. The means of μTBS and DC were analyzed using ANOVA and post hoc Tukey multiple comparisons test. GO nano-filler content showed significant influence on the adhesive μTBS in comparison to controls (p < 0.01). Ageing (TC) revealed significant reduction in the μTBS, except in GOA2 specimens, which showed comparable outcomes among TC and non-TC specimens (p > 0.05). DC was significantly higher in control adhesive [46.8 (3.6)%] compared to GOA2 [37.7 (4.2)%] specimens, however DC was comparable among GOA1 [42.3 (2.9)%] and GOA2 [37.7 (4.2)%] specimens (p > 0.05) respectively. GO exhibited interaction within adhesive and tooth dentin comparable to control adhesive. Increasing GO content showed increase in μTBS of adhesive to dentin, but a decrease in degree of conversion. Under ideal conditions, experimental adhesive with 2% GO content showed acceptable bond strength and DC; and should be further assessed under dynamic conditions to recommend clinical use.

Aim: The study aimed to assess graphene oxide (GO) adhesive and its dentin interaction using scanning electron microscopy (SEM), MicroRaman spectroscopy and Microtensile bond strength (μTBS). Materials and Methods: Experimental GOA and control adhesives (CA) were fabricated. Presence of GO within the experimental adhesive resin was assessed using SEM and Micro-Raman spectroscopy. Ninety specimens were prepared, sixty teeth were utilized for μTBS, twenty for SEM analysis of interface for CA and GOA and ten were assessed using microRaman spectroscopy. Each specimen was sectioned and exposed dentine was conditioned (35% phosphoric acid) for 10 s. The surface was coated twice with adhesive (15 s) and photopolymerized (20 s). Composite build-up on specimen was photo-polymerized. Among the bonded specimens, thirty specimen were assessed using Micro-Raman spectrometer, SEM and energy dispersive X-ray spectroscopy (EDX), whereas remaining specimens were divided in to three sub-groups ( n = 10) based on the storage of 24 h, 8 weeks and 16 weeks. μTBS testing was performed at a crosshead speed of 0.5 mm/min using a microtensile tester. The means of μ-tbs were analyzed using ANOVA and post hoc Tukey multiple comparisons test. Results: No significant difference in μTBS of CA and GOA was observed. Storage time presented a significant interaction on the μTBS ( p < 0.01). The highest and lowest μTBS was evident in CA (30.47 (3.55)) at 24 h and CA (22.88 (3.61)) at 18 weeks. Micro-Raman analysis identified peaks of 1200 cm-1 to 1800 cm1, D and G bands of GO nanoparticles in the resin. Uniform distribution of graphene oxide nanoparticles was present at the adhesive and hybrid layer. Conclusion: GO showed interaction within adhesive and tooth dentin similar to CA, along with formation of hybrid layer. In ideal conditions (absence of nanoleakage), graphene oxide modified adhesive shows comparable bond strength and durability of resin dentine bond.

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Objective: The use of Electronic Nicotine Delivery Systems (ENDS) is increasing rapidly. However, its discoloring effect on dental restorations is not known. This study aimed to evaluate the effect of ENDS aerosol when compared to conventional cigarette smoke (CS) on the color stability of dental ceramic (DC) and resin composite (RC). Methods: This research project was conducted from November 2018 to May 2019. In this study 30 discs each for DC and RC materials were fabricated to be equally divided into groups of exposure to CS, ENDS aerosol and storage in distilled water (No smoke; NS) respectively (n=10). Specimens were exposed for a total of 7 days, with a rate of 10 cycles per day, each cycle represented 10 puffs. The color change was assessed using the CIELAB color space, by calculating ΔE. Data was analysed using ANOVA and multiple comparisons test. Results: Ceramic specimens in CS (2.422 ± 0.771) and ENDS (2.396 ± 0.396) groups showed comparable ΔE (color change) (p=0.992). Similarly, composite specimens in CS (42.871 ± 2.442) and ENDS (46.866 ± 3.64) groups showed comparable ΔE (p>0.05). NS specimens in both composite and ceramic samples showed lower ΔE than CS and ENDS specimens respectively. Conclusions: Aerosol from Electronic nicotine delivery systems (ENDS) showed similar discoloration levels as cigarette smoking (CS). The level of discoloration for ceramic samples for both ENDS and CS was below clinically perceptible levels (Mean ΔE < 2.5). Discoloration of composite resin due to CS and ENDS was visually perceptible (Mean ΔE > 4.0). doi: https://doi.org/10.12669/pjms.36.5.2303 How to cite this:Vohra F, Andejani AF, Alamri O, Alshehri A, Al-Hamdan RS, Almohareb T, et al. Influence of electronic nicotine delivery systems (ENDS) in comparison to conventional cigarette on color stability of dental restorative materials. Pak J Med Sci. 2020;36(5):---------.  doi: https://doi.org/10.12669/pjms.36.5.2303 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Hydroxyapatite (HA) delivery with resin adhesives has potential for re-mineralization of resin–dentin interface. The study prepared an adhesive containing HA and confirmed its presence in adhesive and interaction with the dentin using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Micro-Raman spectroscopy. The aim was to assess the influence of HA incorporation in dentin adhesive on its microtensile bond strength (μ-tbs) and Knoop microhardness (KHN). Thirty teeth each were bonded with CA and HA adhesive using a 10-s smear and photo-polymerized. The specimens in each adhesive group (CA and HA) were divided into sub-groups of 24 h, 8 weeks, and 16 weeks (n = 10) aging durations. μ-tbs was assessed at a crosshead speed of 0.5 mm/minute and bonded interface was analyzed using SEM (n = 20) and Raman spectroscopy (n = 10). Softening of HA adhesive and CA was assessed using KHN. HA adhesive presented higher μ-tbs compared to CA. With an increase in storage time, HA adhesive presented with 100% adhesive failure. Softening was less and KHN was higher for HA adhesive compared to CA (p < 0.05). KHN reduction was higher in CA [19.6 (5.1)%] compared to the HA adhesives [9.7 (4.5)%]. HA adhesive showed superior μTBS and microhardness compared to CA. In the absence of nanoleakage, HA modified adhesive exhibited enhanced bond integrity and better durability of resin dentin bond compared to control adhesive.