Antibacterial Efficacy of Graphene Nanoparticles against Enterococcus faecalis: In Vitro Study.

OBJECTIVE(S): This study compared the antimicrobial efficacy of nanographene (NG) particles with chlorhexidine (CHX) and calcium hydroxide (Ca(OH)2) against Enterococcus faecalis. MATERIALS AND METHODS: Forty extracted human mandibular premolar teeth were cleaned using a scaler, and the middle-third of the root (6 mm) was decoronated using a rotary diamond disk. The inner diameter of the teeth was made consistent using Gates Glidden Drills #3, treated with ethylene diamine tetra-acetic acid and sodium hypochlorite before sterilization. The samples were then contaminated with E. faecalis grown in Tryptic soy broth for 21 days. Tooth samples were then randomly divided into four groups: Group I (Control), untreated saline; Group II, Ca(OH)2; Group III, CHX; and Group IV, NG. The assessment of bacterial growth was carried out by harvesting dentin chips at the end of 1, 3, and 7 days. The colonies were physically counted and tabulated after 24 hours from seeding. Statistical analysis of the collected data was performed with analysis of variance and Tukey's post hoc test using SPSS Version 20.0. RESULTS: The contaminated dentine blocks irrigated with NG (0.5 µg) and CHX (0 ± 0; p < 0.001) had no growth of E. faecalis colonies compared to blocks of Ca(OH)2 (10 ± 21) and saline (927 ± 455). All concentrations of NG (0.5 and 1.0 µg) showed effectiveness higher (p < 0.001) than 2% CHX when measured by the zone of inhibition against E. faecalis. CONCLUSION: It may be concluded that NG is effective against growth of E. faecalis and may be used as a promising antimicrobial agent during root canal treatment. However, further studies should be done to investigate the effect of NG against other dental pathogens.

Assessment of quality improvement of simulation-based learning using an evidence-based framework in dental education.

INTRODUCTION: Simulation-based education is of paramount importance in a dental pre-clinical setting. Hence, continuous quality improvement is crucial to optimize students' knowledge and clinical skills. This study aimed to evaluate the impact of evidence-based simulation learning (EBSL) compared with traditional-based simulation learning (TBSL) using Plan-Do-Study-Act (PDSA) model. MATERIALS AND METHODS: This quality improvement project was undertaken at a private university. Guided by the PDSA model, rubber dam application tasks were conducted in the simulation lab in 2 phases. Phase 1 included TBSL and phase 2 included EBSL comprising of 2 PDSA cycles. 'Plan' stage involved obtaining feedback from students and the concerned staff. 'Do' stage included implementation of EBSL in eight steps adopted from Higgins's framework. 'Study' stage evaluated the outcomes and in 'Act' stage amendments were made to the first EBSL cycle. In the second PDSA cycle re-implementation and evaluation of the rubber dam application exercises were carried out. Descriptive data were presented as percentages and mean scores were compared using paired t-test. RESULTS: Thirty-seven year 2 students participated in this study. A significant improvement in the mean scores was observed between TBSL and EBSL (3.02 + 0.16 and 3.91 + 0.27, respectively, p < .001) using PDSA model with the highest mean score for rubber dam application in the second PDSA cycle for EBSL (4.00 + 0.01). Ninety-five per cent of the students provided positive feedback pertaining to EBSL. CONCLUSION: EBSL was effective in achieving high student satisfaction, desired knowledge, and skills required during simulation-based exercises. The PDSA cycle can be considered to optimize pre-clinical skills learning.

Systematic review on the current state of disaster preparation Simulation Exercises (SimEx).

INTRODUCTION: The simulation exercise (SimEx) simulates an emergency in which an elaboration or description of the response is applied. The purpose of these exercises is to validate and improve plans, procedures, and systems for responding to all hazards. The purpose of this study was to review disaster preparation exercises conducted by various national, non-government, and academic institutions. METHODOLOGY: Several databases, including PubMed (Medline), Cumulative Index to Nursing and Allied Health Literature (CINAHL), BioMed Central, and Google Scholar, were used to review the literature. Information was retrieved using Medical Subject Headings (MeSH) and documents were selected according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). To assess the quality of the selected articles, the Newcastle-Ottawa Scale (NOS) technique was utilized. RESULTS: A total of 29 papers were selected for final review based on PRISMA guidelines and the NOS quality assessment. Studies have shown that many forms of SimEx commonly used in disaster management including tabletop exercises, functional exercises, and full-scale exercises have their benefits and limitations. There is no doubt that SimEx is an excellent tool for improving disaster planning and response. It is still necessary to give SimEx programs a more rigorous evaluation and to standardize the processes more thoroughly. CONCLUSIONS: Drills and training can be improved for disaster management, which will enable medical professionals to face the challenges of disaster management in the 21st century.

Segmental Mobility Studies of Poly(N-isopropyl acrylamide) Interactions with Gold Nanoparticles and Its Use as a Thermally Driven Trapping System.

Thermal desolvation of poly(N-isopropylacrylamide) (PNIPAM) in the presence of a low concentration of gold nanoparticles incorporates the nanoparticles resulting in suspended aggregates. By covalently incorporating <1% acenaphthylene into the polymerization feed this copolymer is enabled to be used as a model to study the segmental mobility of the PNIPAM backbone in response to gold nanoparticles both below and above the desolvation temperature, showing that there is a physical conformational rearrangement of the soluble polymer at ultralow nanoparticle loadings, indicating low affinity interactions with the nanoparticles. Thermal desolvation is capable of extracting >99.9% of the nanoparticles from their solutions and hence demonstrates that poly(N-isopropylacrylamide) can act as an excellent scrubbing system to remove metallic nanomaterial pollutants from solution.

Bilateral Radicular Cyst with Severe Destruction of the Buccal Cortical Plate Secondary to Endodontic Failure.

Large apical radiolucencies after endodontic treatment are usually advised orthograde retreatment, apical surgery and that too with a guarded prognosis. Microsurgical techniques, the use of ultrasonic and magnification aides, have been in use in the developed countries for the past few decades and have shown significant improvement in long-term success of such cases. MTA is proposed as one of the best materials for sealing root end surfaces. In this report, the healing response of cases of 2 large apical radiolucencies, found separately in the anterior maxilla, which were treated by orthograde as well as retrograde endodontic treatments and guided tissue regeneration techniques.

Diaphonization: a recipe to study teeth.

AIM: There are various techniques to study root canal morphology and diaphonization is one of them. There are various methods of decalcification and diaphonization, cited in literature and the main aim of this paper was to give a brief account of the various techniques and share our experience of the technique at a teaching institution in Karachi, Pakistan. MATERIALS AND METHODS: Diaphonization is one of the oldest methods and is based on decalcification of teeth followed by clearing and dye penetration. The specimen is later studied under microscope without sectioning. RESULTS: After the process of clearing a three-dimensional (3D) structure of the internal canal anatomy was visible with naked eye. CONCLUSION: This paper entails a detailed historical background as well as the author's technique including percentages of various chemicals used and the timing of immersion of teeth into these agents. CLINICAL SIGNIFICANCE: The read out is simple and can be subjected to interpretation by direct observation under microscope and can be helpful for students undertaking research in not only the discipline of dentistry but also in other fields such as botany and zoology.

Comparison of orange oil and chloroform as gutta- percha solvents in endodontic retreatment.

OBJECTIVE: To compare the efficacy of gutta-percha removal achieved with simple mechanical technique using two different solvents. MATERIALS AND METHODS: It was an in vitro experimental study conducted at the Aga Khan University Hospital, Karachi, Pakistan on 27 extracted human molars divided into two groups by alternate sampling technique. The teeth were prepared by manual filing and obturated with gutta-percha and calcium hydroxide sealer. Two drops of the assigned solvent were placed on the orifice of the obturated canal and Gates Glidden drills #1, 2 and 3 were used for removal of coronal gutta-percha. Manual filing was done for removal of remaining gutta-percha and the solvent was used in drops until needed. Postoperative periapical radiographs were taken to visualize the remaining gutta-percha left in the canals. Descriptive statistics (mean and SD) of the variables such as tooth type, obturation length and canal curvatures were determined. Chi-square and independent sample t-tests were applied and level of significance was set at 0.05. RESULTS: There was 5.19 (3.8) mm of remaining gutta-percha in the orange oil group and 5.37 (4.2) mm in the chloroform group (p=0.90). CONCLUSION: There is no statistically significant difference between the orange oil and chloroform when used as solvent for removing gutta-percha.