Comparison of the colour accuracy of a single-lens reflex camera and a smartphone camera in a clinical context.

OBJECTIVES: This study aimed to investigate the colour accuracy of digital photographs captured by a single-lens reflex (SLR) camera and a smartphone camera in a clinical setting. METHODS: Dentate subjects were recruited, and their maxillary anterior teeth were photographed along with a colour target and a dental shade guide. There were eight groups: Group 1: SLR camera with a 100 mm macro-lens and a ring-flash (SLRC); Group 2: SLRC with a polarizer; Group 3: SLRC with white-balance calibration; Group 4: SLRC with a polarizer and white-balance calibration. Groups 5 to 8 were similar to Groups 1 to 4, except a smartphone camera and an external light source (SC) were used. The CIE LAB coordinates of the colour target, shade guide, and centre of the maxillary right central incisor (tooth 11) in the digital photographs were retrieved. The colour difference ΔE=[(ΔL*)2+(Δa*)2+(Δb*)2]1/2 to the reference colour coordinates or the reading of the dental spectrophotometer was calculated. The results were analysed by the Kruskal-Wallis test at α=0.05 with Bonferroni correction. RESULTS: Thirty-nine subjects were photographed. SLRC with a polarizer showed the largest ΔE in this study (P<0.001). When capturing tooth 11, SLRC with calibrated white-balance resulted in the smallest ΔE in this study (P<0.001), and the use of a polarizer and/or calibrated white-balance did not result in a smaller ΔE than that of SC alone (P>0.001). CONCLUSION: Calibration for white-balance is recommended for the SLRC. The use of a polarizer does not show an improvement in colour accuracy. SC alone may be sufficient for intraoral photography. CLINICAL SIGNIFICANCE: When capturing intraoral photography using a single-lens reflex camera, it is recommended to calibrate the white-balance. The use of a polarizer does not significantly improve colour accuracy. However, a smartphone camera with an external light source can serve as a viable alternative.

A qualitative analysis of patient's lived experience on their treatment journey with nasopharyngeal carcinoma.

OBJECTIVE: To explore and analyse the perspective of patients undergoing and recovering from nasopharyngeal carcinoma (NPC) therapy. METHODS: Thirty-three NPC patients at different stages of treatment were enroled. Seven were actively undergoing treatment, 13 were immediately post-treatment, and 13 were long-term. Patients were interviewed using a structured questionnaire based on a review of the literature that covered different phases of their treatment journey. The interview was recorded and transcribed for qualitative data analysis using a thematic inductive-deductive approach. RESULTS: Three main domains embracing aspects of NPC patients' experiences were identified; side effects, psychosocial well-being, and the role and support of healthcare workers. Side effects were experienced orally, locally, and systemically. Oral side effects (oral mucositis, xerostomia, altered taste, dysphagia) were the most significant challenge experienced by NPC patients. Locally, skin injury (desquamation, fibrosis, darkening of the skin, erythema, pruritus, and swelling around the neck region) and hair loss, resolved after cessation of therapy. Systemic side effects from the treatment were related to general weakness, weight loss and nausea. The psychosocial well-being of NPC patients was influenced by a range of issues including support (healthcare workers and family), pain management, functional limitations, nutritional needs, perceived level of information, emotion, and finances. CONCLUSION: NPC patients were significantly impacted based on the diagnosis, treatment and recovery phase affecting them locally, systemically, and psychologically. The role of family and healthcare staff was also influential in the overall treatment experience, and they have key roles to play in facilitating patients along their treatment journey. CLINICAL SIGNIFICANCE: Oral and general side effects from NPC treatment have significant impact on patients physical and emotional well-being. It is important for healthcare providers to have insights of these so as to understand and support patients during their treatment journey and recovery and be able to empathetically facilitate their clinical management.

Suppression of cGAS- and RIG-I-mediated innate immune signaling by Epstein-Barr virus deubiquitinase BPLF1.

Epstein-Barr virus (EBV) has developed effective strategies to evade host innate immune responses. Here we reported on mitigation of type I interferon (IFN) production by EBV deubiquitinase (DUB) BPLF1 through cGAS-STING and RIG-I-MAVS pathways. The two naturally occurring forms of BPLF1 exerted potent suppressive effect on cGAS-STING-, RIG-I- and TBK1-induced IFN production. The observed suppression was reversed when DUB domain of BPLF1 was rendered catalytically inactive. The DUB activity of BPLF1 also facilitated EBV infection by counteracting cGAS-STING- and TBK1-mediated antiviral defense. BPLF1 associated with STING to act as an effective DUB targeting its K63-, K48- and K27-linked ubiquitin moieties. BPLF1 also catalyzed removal of K63- and K48-linked ubiquitin chains on TBK1 kinase. The DUB activity of BPLF1 was required for its suppression of TBK1-induced IRF3 dimerization. Importantly, in cells stably carrying EBV genome that encodes a catalytically inactive BPLF1, the virus failed to suppress type I IFN production upon activation of cGAS and STING. This study demonstrated IFN antagonism of BPLF1 mediated through DUB-dependent deubiquitination of STING and TBK1 leading to suppression of cGAS-STING and RIG-I-MAVS signaling.

A microanalysis of expert-student dialogue videos: Supporting preparation and learning for clinical competence assessment.

INTRODUCTION: The aim of this qualitative study was to analyse students' perceptions and impact of using a novel video genre designed to support their learning and preparation for a clinical competence assessment. The videos demonstrate expert-student dialogue (ESD) of authentic, one-on-one discourse between the teacher and student, relating to the case presentation and self-evaluation of the assessment. METHODS: Students who were about to perform a competence assessment were invited to participate in the study. Students were asked to watch a relevant ESD video they had not previously had access to, which showed the examiner-examinee dialogue relating to a peer's tooth preparation for the competence assessment. Immediately after watching the video, a video simulated recall approach was performed to analyse students' perceptions. Thematic analysis was performed to induce relevant themes. RESULTS: Five themes were identified: analysis and judgement, observational learning from expert dialogue, observational learning from student dialogue, self-efficacy and empathy. Positive responses from interviews suggested high cognitive engagement with this video genre with an affective component that was also valued as an informative learning resource. Students reported the video could stimulate them to think, make it easier to remember knowledge, avoid errors observed, and gain insights into assessment process and examiner's expectations. Empathy was also reported towards the examinee in the video. CONCLUSIONS: The ESD videos facilitated students' active and analytical thinking as well as improved their assessment preparedness. This video genre has shown how observing ESD can support students' learning and preparation for a clinical competence assessment.

An exploration of student access to a learning management system-challenges and recommendations for educators and researchers.

INTRODUCTION: This study examined student access to online resources of a faculty's learning management system (LMS). Issues relating to current e-learning resources usage were identified and formed the basis for recommendations to help assist stakeholders in teaching, learning and research. METHODS: Learning analytics from four cohorts of undergraduate dental students were extracted from the database of a LMS spanning between 2012 and 2016. Individual datasets were combined into one master file, re-categorised, filtered and analysed based on cohort, year of study, course and nature of online resource. RESULTS: A total of 157,293 access events were documented. The proportion of administrative to learning data varied across cohorts, with oldest cohort having the highest ratio (82:18) in their final year and most recent cohort having a ratio of 33:67 in their 4th year demonstrating a higher proportion to learning. Seven Learning domains were identified in the access data: access to problem-based learning resources was the highest and next was fixed prosthodontics videos. The prosthodontics discipline had the highest access across the curriculum while some others had very limited or even no learning access events. CONCLUSION: A number of limitations have been identified with the analytics and learning resources in this LMS and engagement with learning resource provision. More detailed data capture of access use and unique identifiers to resources as well as keyword tagging of the resources are required to allow accurate mapping and support of students learning. Moreover, motivation or nudging of students behaviour to more actively engage with learning content needs exploration.

The relation of online learning analytics, approaches to learning and academic achievement in a clinical skills course.

INTRODUCTION: This study examined relationships of students' access of e-learning (learning analytics) for a healthcare psychomotor skills course, approaches to learning (R-SPQ-2F psychometric) and academic achievement (summative examination results). An understanding of the relationships may help in supporting students learning. METHODS: Two consecutive cohorts of 5th year dental students were asked to complete the R-SPQ-2F questionnaire and permission to access data of online videos and associated quizzes and two summative written examination results were examined. The summative assessments were an OSCA and a written-paper question both in prosthodontics. Multiple linear regression and correlation analysis were performed. RESULTS: Students (n=98) performed a total of 10470 video access events and 7714 attempts in online quizzes. Deep learning approach was the strongest predictor variable (ß=0.270; P=.004) on written-paper question result. While video and quiz access were moderately correlated (r=0.600; P<.001) to each other, video access was not a significant predictor to either of the examination results. Quiz access was negatively associated with academic achievement for the written-paper question results (ß=-0.349; P<.001). CONCLUSIONS: Only deep approach to learning appeared to be relevant for the written-paper question examination grades. Conversely, the number of video and quiz access did not relate to either examination results. This suggests e-learning access and examinations do not appear to relate under the conditions explored. Other attributes of learning management access may need to be explored to determine if access to learning management systems may be useful in offering remedial support to students.

A randomised controlled trial of two-unit cantilevered or three-unit fixed-movable resin-bonded fixed partial dentures replacing missing molars.

OBJECTIVE: To examine the short-term clinical performance and patient-reported outcomes of two-unit cantilevered (CL2) and three-unit fixed-movable (FM3) RBFPDs for replacement of single molar-sized spans. MATERIALS AND METHODS: Subjects with an 8-10 mm molar-sized edentulous span(s) and 12 pairs of occluding units were randomly assigned to receive either CL2 or FM3 RBFPD (ratio 1:1). The survival (retention of original prosthesis) and success (survival, complication-free) of RBFPDs at one-year were analysed. Patient-reported outcomes were assessed by prosthesis satisfactory questionnaire and Oral Health Impact Profile (OHIP-49). Data in mean, proportion and longevity were analysed by t-test/Mann-Whitney U test/Wilcoxon signed-rank test, chi-square and log-rank tests respectively at significance level α = 0.05. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT02239718. RESULTS: Ninety-eight RBFPDs (42 CL2 and 56 FM3) were delivered in eighty-three patients. Majority (n = 89) of the prostheses were provided by operators who have less than 2 years of clinical experience. Sixty-six patients with seventy-eight RBFPDs (35 CL2 and 43 FM3) were reviewed at one-year. One CL2 and one FM3 RBFPDs debonded, resulting in a success rate at 97.1 % and 97.7 % respectively (P > 0.05). Both RBFPDs were rebonded and the survival rate were 100 % for both designs. No significant difference in satisfactions and summary OHIP-49 scores were observed (P > 0.05). CONCLUSION: CL2 RBFPDs can be used for replacing molar-sized edentulous spans with minimal observable complications up to one-year. Longer-term data is being collected. CLINICAL SIGNIFICANCE: This clinical trial demonstrates CL2 RBFPDs have comparable clinical and patient-reported outcomes as the FM3 design. This challenges the current dogma in prosthodontics and expands the clinical use of CL2 design which is more conservative, simpler and easier for patients to maintain.

Impact of hypo-salivation on severe tooth wear: A ten-year cohort of patients received radiotherapy for nasopharyngeal carcinoma.

OBJECTIVES: This study was conducted to examine the tooth wear status of nasopharyngeal-carcinoma (NPC) patients who had received radiotherapy at least 5-year previously, and to investigate the salivary parameters that may be associated with the tooth wear. METHODS: Tooth wear status of NPC survivors were clinically assessed using the Exact Tooth Wear Index. A tooth was graded to have severe wear when more than one-third of its buccal/occlusal/lingual surface had dentine loss. At the subject-level, percentages of anterior/posterior/all teeth with severe wear were calculated. Age, number of teeth, flow-rate/buffering capacity/pH of stimulated whole (SWS) and parotid (SPS) saliva's were collected. Correlation and multiple-linear regression tests were performed at the significance level α = 0.05. RESULT: Sixty-eight participants (mean age of 60.0 ±â€¯8.9), 697 anterior and 686 posterior teeth were examined with a mean of 10-years post-radiotherapy. Severe tooth wear was found in 63 (92.6 percent) participants, 288 anterior and 83 posterior teeth. The mean percentage of anterior/posterior/all teeth with severe wear were 42.3 ±â€¯28.1, 14.5 ±â€¯19.9 and 30.0 ±â€¯21.7. Anterior teeth, particularly the incisal surface of central incisors were most affected. The mean flow-rate of SWS and SPS were 0.1 ±â€¯0.1 ml/min and 0.03 ±â€¯0.07 ml/min respectively. Thirty (44.1 percent) and 48 (70.6 percent) participants were found to have low/no buffering capacity of SWS and SPS respectively. Multiple-regression analyses revealed the SWS flow-rate was associated with the percentage of anterior teeth with severe wear (p=0.03). CONCLUSION: Anterior tooth wear is a significant dental problem among NPC survivors and was associated with hypo-salivation. CLINICAL SIGNIFICANCE: Patients with hypo-salivation should be being monitored for tooth wear particularly on the anterior teeth.

The adverse effects of tungsten carbide grinding on the strength of dental zirconia.

OBJECTIVES: This study investigated the effects of tungsten-carbide grinding on the surface characteristics and mechanical strength of dental 3 mol% yttria-stabilized zirconia (3Y-TZP). METHODS: Two types of tungsten-carbide burs (TC), 6-blade (TC1) and 8-blade (TC2) were used to grind 3Y-TZP, in a dental air-turbine handpiece with water-cooling and were also subjected to air-particle abrasion (APA): TC1 + APA and TC2 + APA; and rubber polishing (RP): TC1 + RP and TC2 + RP; one group received only rubber-polishing RP. The control group received no treatment. Surface characterization was examined by surface roughness (Ra) and atomic force microscopy. Specimens were also observed with scanning electron microscopy (SEM) and X-ray-diffraction (XRD) for microstructure and crystalline phases. A piston-on-three-balls biaxial-flexural strength (BFS) test was performed with 15 samples-per-group and the broken specimen were observed under SEM to investigate the fracture origin pattern. One-way ANOVA, Kruskal-Wallis test and Weibull analysis were performed at α = 0.05. RESULTS: Groups TC1 and TC2 had the lowest mean BFS (p < 0.05) with up to 74 % reduction in strength. APA and RP both significantly increased the mean BFS after tungsten-carbide grinding but was still less than the control (p < 0.05). Compared to the control, the mean BFS was significantly reduced for all groups except for the RP group (p < 0.05). APA and rubber-polishing following TC2 grinding had significant higher mean BFS than those following TC1 grinding respectively (p < 0.05). SEM revealed distinct micro-cracks after tungsten-carbide grinding. SIGNIFICANCE: Tungsten-carbide burs (6- and 8-blade) are not recommended for zirconia grinding due to the significant reduction of biaxial-flexural strength and observed micro-structural surface and subsurface damage.

A comparison of visual identification of dental radiographic and nonradiographic images using eye tracking technology.

OBJECTIVES: Eye tracking has been used in medical radiology to understand observers' gaze patterns during radiological diagnosis. This study examines the visual identification ability of junior hospital dental officers (JHDOs) and dental surgery assistants (DSAs) in radiographic and nonradiographic images using eye tracking technology and examines if there is a correlation. MATERIAL AND METHODS: Nine JHDOs and nine DSAs examined six radiographic images and 16 nonradiographic images using eye tracking. The areas of interest (AOIs) of the radiographic images were rated as easy, medium, and hard, and the nonradiographic images were categorized as pattern recognition, face recognition, and image comparison. The participants were required to identify and locate the AOIs. Data analysis of the two domains, entire slide and AOI, was conducted by evaluating the eye tracking metrics (ETM) and the performance outcomes. ETM consisted of six parameters, and performance outcomes consisted of four parameters. RESULTS: No significant differences were observed for ETMs for JHDOs and DSAs for both radiographic and nonradiographic images. The JHDOs showed significantly higher percentage in identifying AOIs than DSAs for all the radiographic images (72.7% vs. 36.4%, p = .004) and for the easy categorization of radiographic AOIs (85.7% vs. 42.9%, p = .012). JHDOs with higher correct identification percentage in face recognition had a shorter dwell time in AOIs. CONCLUSIONS: Although no significant relation was observed between radiographic and nonradiographic images, there were some evidence that visual recognition skills may impact certain attributes of the visual search pattern in radiographic images.

Is there a need for postoperative antibiotics after third molar surgery? A 5-year retrospective study.

AIM: Randomized controlled trials might be reporting a higher postoperative infection rate for third molar surgery compared to other study designs due to unclear criteria for the classification of "infections". The aim of the present retrospective study was to assess the infection rate after third molar surgery with and without postoperative antibiotic prescription. METHODS: Case records of patients who underwent third molar extractions at the Prince Philip Dental Hospital in Hong Kong between 3 July 2012 and 22 June 2017 were evaluated retrospectively. Data extraction was performed for indications, clinical and radiographic findings, antibiotic treatment, postoperative complications, and treatment for postoperative infection. The odds ratio (OR) for postoperative infection was estimated. RESULTS: In total, 1615 extracted over 5 years from 992 patient records were included in the final analysis. Antibiotics were prescribed postoperatively for 44% of the extractions. The overall infection rate was 2.05%. There was no significant difference in infection rates between the groups which underwent extractions with or without antibiotics (OR = .68; P = .289). We found a significantly higher risk for infections with increasing age (P = .002). CONCLUSION: Infection rates after third molar extraction is minimal in the current setting, with no significant benefit from postoperative antibiotic prescription.

Evaluation of student use of videos to support learning in a simulation laboratory course: A perception and analytics approach.

AIM: This paper evaluates the use of online video learning materials used for a simulation laboratory course for 2 consecutive cohorts of students using an evaluation and analytics approach. METHODS: 100 online video clips were created to support students' learning before, during and after the scheduled simulation laboratory teaching sessions in a fixed prosthodontics course. Videoed online presentations included screen-captured PowerPoint presentations, simulation laboratory psychomotor and clinical skills demonstrations, individual student case consultations and whole-class worksheet debriefings. Data files and access data were analyzed for 2 consecutive cohorts of 4th year students. An evaluation questionnaire was administered on the 2015 cohort. RESULTS: Feedback on learning resources were strongly positive. 100% of students reported that the videos helped in their learning, preparation for simulation laboratory classes, to refresh their memory prior to clinical care, prepare for the clinical competency test and prepare for examinations. In total, 4689 videos were accessed, 35% by class 2015 and 65% by 2016. 73% of these were watched during the simulation laboratory course, 13% were watched 2-3 weeks before examinations and 14% during the remainder of the year. CONCLUSION: Videos were reported to support student learning and were valued for a range of learning needs. However, significant differences between student consumption and strategies need to be designed to engage low consumers.

Ten-year clinical evaluation of posterior fixed-movable resin-bonded fixed partial dentures.

OBJECTIVES: Two-unit cantilevered resin-bonded fixed partial dentures (RBFPDs) offer long-term retention for anterior and premolar-sized spans. At this center, molar and longer spans have been restored with fixed-movable (FM) RBFPDs to overcome the lower retention rates of fixed-fixed RBFPDs. This retrospective study aimed to evaluate the long-term longevity and the patient-reported outcomes of posterior FM-RBFPDs. METHODS: Posterior FM-RBFPDs that had been inserted at least five years were reviewed. Survival was "retention of the original prosthesis in mouth" and success was "survival of prosthesis and absence of complications requiring treatment intervention". Prosthesis location, number of units, insertion year, tooth/teeth replaced and operator experience were collected. Patients' acceptance to FM-RBFPDs were assessed using prosthesis satisfaction questionnaire and Oral Health Impact Profile (OHIP-49). Results were analyzed using log-rank and cox-regression tests at significance level α = 0.05. RESULTS: One-hundred-and-one prostheses were examined. The mean observation time was 126.4 ±â€¯32.2 months. Thirty-six (35.6%) and 63 (62.4%) FM-RBFPDs were rated as success and survival respectively. Prostheses inserted after year 2001 (n = 69) experienced 42.0% (n = 29) success and 75.4% (n = 52) survival, and its survival rate was significantly better than those inserted in or before 2001 (p = 0.01). Five- and ten-year cumulative survival probability of FM-RBFPDs inserted after year 2001 were 82.3% and 74.1% respectively. The most frequent complications were debonding among 34 (33.7%) prostheses. Patients' acceptance were high. CONCLUSIONS: More recently inserted prostheses showed improved longevity and patients' acceptance to posterior FM-RBFPDs were high. CLINICAL SIGNIFICANCE: Fix-Movable RBFPDs are a viable tooth replacement option in the posterior region.

Adhesive and oxidative response of stem cell and pre-osteoblasts on titanium and zirconia surfaces in vitro.

AIM: The aim of the present study was to investigate the initial stem cell and pre-osteoblast cell adhesion and oxidative response on zirconia in comparison with titanium. METHODS: Human dental pulp stem cells (DPSC) and murine pre-osteoblasts (MC3T3-E1) cells were cultured on zirconia and titanium surfaces, and at 3-, 12-, and 24-hour intervals, cell viability and morphology were determined with tetrazolium based colorimetric assay, scanning electron microscopy, and immunofluorescence analysis. The in situ reactive oxygen species level of both cells on each material surface was examined after 24-hour culture. RESULTS: Both DPSC and MC3T3-E1 cells revealed comparable morphological features during 24-hour cell adhesion processes, with cells continued expanding of cell size and increasing of cell viability on titanium and zirconia surfaces during 24-hour culture. Zirconia demonstrated relatively higher mean cell viability compared to titanium within 24-hour culture, with significantly higher DPSC viability at 12 hours after seeding (P < 0.05). Relatively higher mean reactive oxygen species levels in both DPSC and MC3T3E1 were found on zirconia surfaces after 24-hour culture compared to titanium. CONCLUSIONS: From the results, zirconia as a potential dental implant substrate demonstrated equivalent or better initial cellular responses compared to titanium.

Use of Learning Analytics Data in Health Care-Related Educational Disciplines: Systematic Review.

BACKGROUND: While the application of learning analytics in tertiary education has received increasing attention in recent years, a much smaller number have explored its use in health care-related educational studies. OBJECTIVE: This systematic review aims to examine the use of e-learning analytics data in health care studies with regards to how the analytics is reported and if there is a relationship between e-learning analytics and learning outcomes. METHODS: We performed comprehensive searches of papers from 4 electronic databases (MEDLINE, EBSCOhost, Web of Science, and ERIC) to identify relevant papers. Qualitative studies were excluded from this review. Papers were screened by 2 independent reviewers. We selected qualified studies for further investigation. RESULTS: A total of 537 papers were screened, and 19 papers were identified. With regards to analytics undertaken, 11 studies reported the number of connections and time spent on e-learning. Learning outcome measures were defined by summative final assessment marks or grades. In addition, significant statistical results of the relationships between e-learning usage and learning outcomes were reported in 12 of the identified papers. In general, students who engaged more in e-learning resources would get better academic attainments. However, 2 papers reported otherwise with better performing students consuming less e-learning videos. A total of 14 papers utilized satisfaction questionnaires for students, and all were positive in their attitude toward e-learning. Furthermore, 6 of 19 papers reported descriptive statistics only, with no statistical analysis. CONCLUSIONS: The nature of e-learning activities reported in this review was varied and not detailed well. In addition, there appeared to be inadequate reporting of learning analytics data observed in over half of the selected papers with regards to definitions and lack of detailed information of what the analytic was recording. Although learning analytics data capture is popular, a lack of detail is apparent with regards to the capturing of meaningful and comparable data. In particular, most analytics record access to a management system or particular e-learning materials, which may not necessarily detail meaningful learning time or interaction. Hence, learning analytics data should be designed to record the time spent on learning and focus on key learning activities. Finally, recommendations are made for future studies.

An systematic review of e-learning outcomes in undergraduate dental radiology curricula-levels of learning and implications for researchers and curriculum planners.

OBJECTIVES: To examine the outcomes of e-learning or blended learning interventions in undergraduate dental radiology curricula and analyze the nature of the knowledge levels addressed in learning interventions. METHODS: A systematic literature review was performed using a search strategy based on MeSH key words specific to the focus question and indexed in the MEDLINE database. The search again was supplemented by hand-searching of selected journals. Data were extracted relating to outcomes of knowledge and student perceptions. Analysis of the e-learning intervention was performed using a new framework to examine the level of knowledge undertaken: (1) remember/understand (2) analysis or evaluation or diagnosis and (3) performance ("knows how" or "shows how"). RESULTS: From the selected 17 papers, 11 were positive about student reported outcomes of the interventions, and 8 reported evidence that e-learning interventions enhanced learning. Out of the included studies, 8 used e-learning at the level of remember/understand, 4 at the level of analysis/evaluate/diagnosis, and 5 at the level of performance ("knows how," "shows how"). CONCLUSIONS: The learning objectives, e-learning intervention, outcome measures and reporting methods were diverse and not well reported. This makes comparison between studies and an understanding of how interventions contributed to learning impractical. Future studies need to define "knowledge" levels and performance tasks undertaken in the planning and execution of e-learning interventions and their assessment methods. Such a framework and approach will focus our understanding in what ways e-learning is effective and how it contributes to better evidence-based e-learning experiences.

Silver deposition on demineralized dentine surface dosed by silver diammine fluoride with different saliva.

AIM: Silver diammine fluoride (SDF) is an anticaries agent that binds to tooth tissue. The aim of the present study was investigate the dose-response effect of SDF on demineralized dentine in basal medium mucin (BMM) saliva substitute and human saliva. METHODS: Dentine discs stored in saliva substitute, BMM, and human unstimulated whole saliva (UWS) were chemically demineralized, and 10 µL of 10 wt%, 24 wt%, or 38 wt% SDF was applied and then stored in its respective saliva (BMM or UWS) for 5 days. Dentine disc samples were digested in 70% HNO3 , and silver was quantitatively detected by inductively coupled plasma mass spectroscopy. RESULTS: For both the BMM and UWS groups, the presence of silver increased proportionally with increasing concentrations of SDF (P < 0.05). For the 38 wt% SDF application, the mean absorption percentage of silver in dentine was 3.90% for the UWS group and 6.61% for the BMM group. The BMM group was found to yield a significantly higher amount of silver compared to UWS at 10 wt% and 38 wt% SDF application (α = 0.05); 38 wt% SDF interacts more with BMM with higher silver deposition than UWS. CONCLUSION: The amount of silver found in dentine was in proportion to the concentration of SDF. Extrapolation of in vitro investigations using artificial saliva for SDF tooth interactions should be interpreted with caution.

A Systematic Review of Amalgam Bonded Restorations: In vitro and Clinical Findings.

AIM: This article aims to systematically review the evidence reporting on physical properties of bonded amalgam, its clinical performance, and implications. MATERIALS AND METHODS: An electronic search in "Medline" (search term: Amalgam and Dentin bonding) from 1987 to 2013 yielded 465 publications out of which 170 articles were selected for the analysis. Data were extracted relating to the bond strength of amalgam to dentin, microleakage, postoperative sensitivity, and longevity of bonded amalgam restorations. RESULTS: A total of 129 in vitro studies out of 170 articles showed high bond strengths with filled adhesive resins and light-cured adhesives, in particular Amalgambond plus and Optibond adhe-sives. Thickness of bonding agent, type of alloy, and thermo-cycling showed inconclusive outcomes between bonded and nonbonded amalgam restorations. Majority of studies reported reduced microleakage when dentin bonding agents and resin-modified glass ionomer cements (RM-GICs) were used with amalgam. However, water stored, thermocycled, and spherical amalgam alloys resulted in higher microleakage. While bonded amalgam facilitated the retention of large restorations, reduction in postoperative sensitivity was not consistently observed between bonded and nonbonded amalgam restorations. CONCLUSION: While bonded amalgam restorations reduce the need for mechanical retention conserving tooth structure and reducing the adverse effects of microleakage, there is lack of consistent evidence across all outcome domains to advocate the benefit of bonding of all amalgam restorations. Despite this, it can be considered the material of choice for large restorations and bonding enhances retention in vitro which can be considered beneficial clinically. CLINICAL SIGNIFICANCE: The use of adhesives to bond amalgam to the tooth structure offers potential advantages, as it helps in conservative cavity preparation without compromising the retention to tooth, making it a material of choice in large posterior restorations.

Antibacterial Effect of Silver Diammine Fluoride on Cariogenic Organisms

AIM: To screen the possible antimicrobial activity of a range of clinically used, silver-based compounds on cariogenic organisms: silver diammine fluoride (SDF), silver fluoride, and silver nitrate. MATERIALS AND METHODS: Preliminary screening disk-diffusion susceptibility tests were conducted on Mueller-Hinton agar plates inoculated with Streptococcus mutans, Lactobacillus acidophilus, and Actinomyces naeslundii, organisms known to be cariogenic. In order to identify which component of the silver compounds was responsible for any antibacterial (AB) effect, and to provide controls, the following were also investigated at high and low concentrations: sodium fluoride, ammonium fluoride, ammonium chloride, sodium fluoride, sodium chloride, and sodium nitrate, as well as deionized water as control. A volume of 10 pL of a test solution was dispensed onto a paper disk resting on the inoculated agar surface, and the plate incubated anaerobically at 37°C for 48 hours. The zones of inhibition were then measured. RESULTS: Silver diammine fluoride, silver fluoride, silver nitrate, and ammonium fluoride had significant AB effect (p < 0.05) on all three test organisms, although ammonium fluoride had no effect at low concentration; the remaining other compounds had no effect. CONCLUSION: Silver ions appear to be the principal AB agent at both high and low concentration; fluoride ions only have an AB effect at high concentration, while ammonium, nitrate, chloride and sodium ions have none. The anticaries effect of topical silver solutions appears restricted to that of the silver ions. CLINICAL SIGNIFICANCE: Silver compounds, such as SDF, silver fluoride, and silver nitrate have AB effect against cariogenic organisms and these may have clinical impact in arresting or preventing dental decay. Sodium fluoride did not have AB effect under the conditions tested.

Oral Rehabilitation of Young Adult with Amelogenesis Imperfecta.

BACKGROUND: Amelogenesis imperfecta is a heterogeneous group of hereditary disorders that affect the enamel formation of the primary and permanent dentitions while the remaining tooth structure is normal. Appropriate patient care is necessary to prevent adverse effects on dental oral health, dental disfigurement, and psychological well-being. AIM: This clinical report presents a 27-year-old Chinese male with amelogenesis imperfecta (AI) and his restorative management. CASE REPORT: This clinical report presents a 27-year-old Chinese male with AI and his restorative management. Extraoral examination showed a skeletal class III profile and increased lower facial proportion. Intraorally, all the permanent dentition was hypoplastic with noticeable tooth surface loss and a yellow-brown appearance. This was complicated with a mild maloc-clusion and food packing on his posterior teeth. The patient wanted to improve his appearance and masticatory efficiency. Orthodontic treatment was performed to treat the mild malocclu-sion and create physiological interproximal spacing to minimize tooth preparation and facilitate oral hygiene. CONCLUSION: This report demonstrates how a multidisciplinary approach for the management of AI can achieve a predictable, functional, and esthetic outcome. Orthodontic treatment facilitated a conservative prosthodontic treatment outcome by selectively increasing interproximal space, minimizing tooth preparation, correcting posterior bilateral cross-bite, as well as an anterior reverse overjet and derotation of the canines. CLINICAL SIGNIFICANCE: This case report demonstrates the effective restoration of AI using a multidisciplinary approach to overcome crowding using a relatively conservative approach.