Posterior two-unit cantilevered zirconia resin-bonded fixed partial dentures: A 3-year prospective single-arm clinical trial.

OBJECTIVES: To evaluate the longevity of cantilevered zirconia-based resin-bonded fixed partial dentures (RBFPDs) in replacing missing posterior teeth, as well as the quality of life and patient satisfaction experienced by those receiving zirconia RBFPDs. METHODS: A prospective single-arm uncontrolled clinical trial was conducted to replace one or more missing premolars or molars with a span of 5 to 8 mm using cantilevered zirconia RBFPDs. Thirty-six participants with 40 prostheses were recruited and underwent a 3-year clinical evaluation. The retainer designs included a minimum thickness of 0.8 mm, a minimum of 200° circumferential wraparound with an occlusal bar, and a connector dimension of 3 × 3 mm. Patient-reported outcomes, including patient satisfaction and Oral Health Impact Profile (OHIP), were assessed. RESULTS: The average age of participants was 45.8 years, and 72.5 % were women. The success rate of the posterior zirconia RBFPDs was 76.2 %, with an estimated mean success duration of 46.1 months. The survival rate was 88.1 %, with an estimated mean survival duration of 49.4 months. Participants were highly satisfied with the treatment, achieving an average satisfaction score of 80.8 ± 11.9. Participants' total OHIP scores decreased from 52.3 to 39.6 after 3 years, indicating a significant improvement in oral health-related quality of life (P = 0.009). CONCLUSIONS: After 3 years, a moderately high survival rate and favourable patient-reported outcomes of posterior cantilevered zirconia RBFPDs were achieved. Therefore, it can be recommended as a conservative treatment option to replace missing posterior teeth, provided that retainer design considerations are taken into account. CLINICAL SIGNIFICANCE: Cantilevered zirconia RBFPDs for posterior teeth can serve as a conservative treatment option that is both aesthetically pleasing and biocompatible. It offers a more cost-effective alternative compared to dental implants, which are often prohibitively expensive for the majority of patients. This approach has the potential to greatly improve patient-reported outcomes.

Well-being of undergraduate dental students: Questionnaire design, findings and future directions.

INTRODUCTION: The recent pandemic has highlighted the importance of addressing well-being in the overall health of students. There is a need for support systems within dental schools to help students demonstrate resilience, adapt to learning environments and thrive in their professional careers. OBJECTIVES: The main aim of the study was to evaluate Bachelor of Dental Surgery (BDS) students' understanding and experience of well-being. The objectives were to create a suitable survey to assess students' well-being, investigate the factors affecting dental students' well-being and develop a student well-being action plan based on the analysis of the survey. METHODS: A literature review was conducted to identify and critically assess existing measures of well-being in dental students. Four domains of well-being (emotional, physical, social, intellectual) relevant to dental students were identified. Through a comprehensive iterative process, a two-part survey was developed and tested, which measured individual experiences of well-being across the four domains and collected feedback on proposed initiatives to support student well-being. The survey was disseminated to all 452 dental students from Years 1 through 6, of which 71% (321) responded. RESULTS: The survey revealed low levels of overall well-being among the dental student population, which worsened with increasing years of clinical study. Fear of failing exams presented the biggest challenge with regard to emotional well-being, while sleep deprivation and occupational health hazards most affected the physical well-being domain. Intellectual well-being was compromised by insufficient free time to pursue extracurricular interests and concerns about achieving the required skills. Despite a majority experiencing positive relationships with their peers and tutors, less than a fifth agreed that the Faculty of Dentistry 'supported my well-being as a dental student'. CONCLUSION: As the first investigation of the well-being of dental students in Hong Kong, the key stressors identified were examinations, long schedules and the physical burden of dental work, which are consistent with international literature. The findings reveal students' needs and preferences for well-being initiatives which will be optimized in the implementation of student-centred curricular activities.

Near-peer teaching in a psychomotor skills course: Benefits, challenges and solutions.

INTRODUCTION: This study evaluates the perceptions and experiences of students in the role of near-peer teachers in a psychomotor skills course. MATERIALS AND METHODS: Final year BDS students were invited to participate as near-peer teachers in a 4th-year conventional bridges course. Near-peer teachers attended eight sessions (3 h) of simulation laboratory teaching relating to conventional bridge tooth preparations and provided feedback on near-peer tooth preparations and answered their questions. Interviews were conducted with all near-peer teachers to evaluate their perceptions of this novel teaching and learning experience and a thematic analysis was performed to analyse the data. RESULTS: Near-peer teachers reported this to be a rewarding, enjoyable and challenging experience. They benefited from learning and revising content-related materials as well as gained insights and teaching skills through the peer teaching process. Students felt supported and learned from peers and teaching staff and some used dyad teaching as a strategy to overcome perceived challenges. Students also reported the benefits of social and cognitive congruence in interacting with junior peers. However, students reported the feeling of inadequacy or lack of confidence and suggested the need for a training to prepare them better for the course. CONCLUSION: This paper reports on the benefits as well as challenges perceived by near-peer teachers during simulation laboratory teaching experience. We provide solutions into how to better prepare students for such teaching experience.

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 dentists' understanding and management of non-carious cervical lesions (NCCL).

INTRODUCTION: Non-carious cervical lesions (NCCLs) are considered to have a multi-factorial aetiology and their management is affected by a range of variables perhaps most importantly clinical judgement. The aim of this study was to elicit information from practicing dentists, using interviews, to explore their understanding of NCCL aetiology, the decision-making criteria of when to restore, and the restorative techniques used to restore NCCLs. This may help identify gaps or anomalies in our understanding to inform future research and clinical practice for the management of NCCLs. METHODS: An interview guide was developed from a literature search which formed 2 domains framed around understanding and management of NCCLs based on: understanding of diagnosis and aetiology, and factors affecting decision making for management. Practicing dentists with more than 10 years of experience were purposively recruited to conduct in-depth, semi-structured interviews. Fifteen interviews were audio recorded and transcribed verbatim. A thematic content analysis was conducted and the results analysed. RESULTS: From the thematic analysis, 2 domains were identified. In the domain of "diagnosis and aetiology", while participants have similar understanding and methods of diagnosing NCCL, most stated NCCLs in a patient were caused by a "main aetiology" such as "abrasion", "abfraction" while few described the inter-relationship of these aetiological factors. In the domain of "factors affecting decision making". "Patient reported symptoms" and "lesion dimension" were the main factors that affected participants' decision to provide restorative or non-restorative management. However, a "restorative threshold" was not able to be identified. CONCLUSION: There was notable variety in participants' understanding of the aetiology, management, and treatment of NCCLs, particularly the restorative threshold of when to treat. CLINICAL SIGNIFICANCE: The variability demonstrates the need to have a clearer understanding of the key elements that affect the management of NCCLs and better information to support the decision of when to treat.

Reliability of online dental final exams in the pre and post COVID-19 era: A comparative study.

Amidst the fourth COVID-19 wave in Viet Nam, national lockdowns necessitated the closure of numerous dental schools. To assess DDS (Doctor of Dental Surgery) graduation exams, this study analyzed their 2021 implementation in comparison to onsite exams conducted in 2020 and 2022 at the Faculty of Odonto-Stomatology, University of Medicine and Pharmacy at Ho Chi Minh City, Viet Nam (FOS-UMPH). The final online examination comprises two main sessions: a synchronous online examination using FOS-UMPH e-Learning for theories (consisting of 200 MCQs and 3 written tests with 3 clinical situations needed be solved) and a synchronous online examination using Microsoft Teams for practicum (comprising of 12 online OSCE stations). The final grades were evaluated using the same metrics in face-to-face final examinations in 2022 and 2020. A total of 114, 112 and 95 students were recruited for the first-time exams in 2020, 2021 and 2022, respectively. In order to analyze the reliability, histogram and k-mean clustering were employed. The histograms from 2020, 2021 and 2022 showed a striking similarity. However, fewer students failed in 2021 and 2022 (13% and 12.6%, respectively) compared to 2020 (28%), with clinical problem-solving part grades (belonging to theory session) being notably higher in 2021 and 2022. Intriguingly, the MCQ Score results showed the identical patterns. The courses of orthodontics, dental public health, and pediatrics subjects (in the group of prevention and development dentistry) stood out for their exceptional accuracy across both sessions. After examining data gathered over three years, we identified three distinct clusters: the first comprised of scattered average and low scores, the second characterized by high scores but unstable and scattered and the third cluster boasting consistently high and centered scores. According to our study, online and onsite traditional graduation exam results are relatively equivalent, but additional measures are necessary to standardize the final examination and adapt to the new normal trend in dental education.

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.

Near-peer teaching for learning clinical photography skills: Perceptions of students.

AIM: This paper evaluates the perceptions and experience of students, in the role of both near-peer teacher and learner who participated in the clinical dental photography course, using a mixed-method analysis with focus group interviews of student tutors and a questionnaire of learner perceptions. METHODS: A student-led course on Digital Clinical Photography took place with BDS 5 and 6 students as near-peer teachers (NPTs) and BDS 2 and 3 students as learners. Interviews were conducted with near-peer teachers, and a questionnaire was distributed to learners to evaluate students' perceptions of this novel teaching and learning experience. RESULTS: Near-peer teaching has proven to be a beneficial alternative teaching pedagogy which was well-received by NPTs and student learners. The content creation and teaching experience deepened NPTs' understanding on the subject matter and were motivated given the autonomous nature of the project. NPTs enjoyed and benefited from the collaborative nature of the project and the relevance of the subject matter and improved their clinical skills. The student learners enjoyed the learning experience and benefits of learning from NPTs which is supported by social and cognitive congruence. The positive perception of teaching and learning in pairs were also described. CONCLUSION: This project demonstrates the perceived benefits of near-peer teaching for clinical photography skills for student experiential learning and highlights key elements on how to structure such an activity to engage and support students to participate in such future activities.

An exploration of clinical communication needs among undergraduate dental students.

INTRODUCTION: This study examines undergraduate dental students' perceptions of their self-confidence in communicating with patients and paradental staff. MATERIALS AND METHODS: A survey questionnaire was designed based on a literature review and input from students and academic staff relating to clinical communication skills with 19 questions across 7 domains. Through email, a convenience sampling of undergraduate students were invited to complete the survey questionnaire. Qualitative and quantitative analysis of the responses was performed with a thematic analysis to the open-ended questions. RESULTS: In total, 102 students were surveyed from 4 years of students with a 36.6% response rate. Students reported some areas of low confidence across various communication domains, in particular, building rapport, behavioural change, management of patient expectation and breaking bad news. Students reported insufficient confidence and knowledge in specialist clinical areas, layperson terms and success rates and longevity of treatment items when communicating with patients. Information sheets and visual aids such as models or photos were suggested by students to be helpful in patient communication. Students also reported challenges in communication with nurses when they might challenge or change their clinical decisions in front of their patients. CONCLUSION: Our study reveals areas of low confidence among undergraduate dental students in communication towards patients and paradental staff. Barriers and challenges have been identified with an action plan suggested accordingly. There is a need for additional training in the form of learning content and communications experiences, and channels of communications for undergraduate students.

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.

Compositional profile of mucosal bacteriome of smokers and smokeless tobacco users.

INTRODUCTION: Smoked, and especially smokeless, tobacco are major causes of oral cancer globally. Here, we examine the oral bacteriome of smokers and of smokeless tobacco users, in comparison to healthy controls, using 16S rRNA gene sequencing. METHODS: Oral swab samples were collected from smokers, smokeless tobacco users, and healthy controls (n = 44). Microbial DNA was extracted and the 16S rRNA gene profiled using the Illumina MiSeq platform. Sequencing reads were processed using DADA2, and taxonomical classification was performed using the phylogenetic placement method. Differentially abundant taxa were identified using DESeq2, while functional metagenomes based on KEGG orthology abundance were inferred using LIMMA. RESULTS: A significantly higher microbial diversity was observed in smokeless tobacco users and smokers relative to controls (P < 0.05). Compositional differences in microbial communities were observed in all comparisons with healthy controls (PERMANOVA P < 0.05) but not between smokers and smokeless tobacco users. Levels of Fusobacterium spp., Saccharibacterium spp., and members of Shuttleworthia were elevated in smokers when compared to controls (BH adj P < 0.01). In addition, the relative abundance of three bacterial taxa belonging to genera Fusobacterium spp., Catonella, and Fretibacterium spp. was significantly increased in smokeless tobacco users relative to controls (BH adj P < 0.01). Major functional pathways significantly increased in smokeless tobacco users relative to both controls, and smokers were similar and involved amino acid metabolism including glutamate and aspartate biosynthesis and degradation (log FC > 1.5; BH adj P < 0.01). CONCLUSIONS: A distinct taxonomic and functional profile of oral microbiome in smokers and smokeless tobacco users as compared to healthy controls implicates a significant role of microbes and their metabolites in diseases associated with tobacco use including oral cancer. CLINICAL RELEVANCE: Future efforts in preventive, diagnostic, curative, and prognostic strategies for diseases associated with tobacco use in smokers and smokeless tobacco users could incorporate the oral microbiome.

A flipped classroom, same-level peer-assisted learning approach to clinical skill teaching for medical students.

BACKGROUND: Clinical procedural skills are vital components of medical education. Increased student intake and limited capacity of medical schools necessitate more efficient ways to deliver clinical skill teaching. This study employed a flipped classroom, peer-assisted learning approach to deliver clinical skill teaching. It aimed to determine the influence of pre-class demonstration video watching and in-class student-student interactions on clinical skill acquisition. METHODS: In 2017, a cohort of 205 medical students in their penultimate year of undergraduate medical study were recruited, and they learned bag mask ventilation and intravenous cannulation during this study. The participants watched a demonstration video before class, and then underwent self-directed practice as triads. Afterwards, each participant video-recorded their skill performance and completed post-class questionnaires. The videos were evaluated by two blinded assessors. RESULTS: A hundred and thirty-one participants (63.9%) completed the questionnaire. For bag mask ventilation, participants who claimed to have watched the corresponding demonstration video before class achieved higher performance scores (those who watched before class: 7.8 ± 1.0; those who did not: 6.3 ± 1.7; p < 0.01). For intravenous cannulation, while there is no significant difference in performance scores (those who watched before class: 14.3 ± 1.3; those who did not: 14.1 ± 1.4; p = 0.295), those who watched the video before class received less interventions from their peers during triad practice (those who watched before class: 2.9 ± 1.8; those who did not: 4.3 ± 2.9; p < 0.05). The questionnaire results showed that most participants preferred the new approach of clinical skill teaching and perceived it to be useful for skill acquisition. CONCLUSION: The flipped classroom, same-level peer-assisted learning model is potentially an effective way to address the current challenges and improve the efficiency of clinical procedural skill teaching in medical schools.

Suppression of JAK-STAT Signaling by Epstein-Barr Virus Tegument Protein BGLF2 through Recruitment of SHP1 Phosphatase and Promotion of STAT2 Degradation.

Some lytic proteins encoded by Epstein-Barr virus (EBV) suppress host interferon (IFN) signaling to facilitate viral replication. In this study, we sought to identify and characterize EBV proteins antagonizing IFN signaling. The induction of IFN-stimulated genes (ISGs) by IFN-ß was effectively suppressed by EBV. A functional screen was therefore performed to identify IFN-antagonizing proteins encoded by EBV. EBV tegument protein BGLF2 was identified as a potent suppressor of JAK-STAT signaling. This activity was found to be independent of its stimulatory effect on p38 and JNK pathways. Association of BGLF2 with STAT2 resulted in more pronounced K48-linked polyubiquitination and proteasomal degradation of the latter. Mechanistically, BGLF2 promoted the recruitment of SHP1 phosphatase to STAT1 to inhibit its tyrosine phosphorylation. In addition, BGLF2 associated with cullin 1 E3 ubiquitin ligase to facilitate its recruitment to STAT2. Consequently, BGLF2 suppressed ISG induction by IFN-ß. Furthermore, BGLF2 also suppressed type II and type III IFN signaling, although the suppressive effect on type II IFN response was milder. When pretreated with IFN-ß, host cells became less susceptible to primary infection of EBV. This phenotype was reversed when expression of BGLF2 was enforced. Finally, genetic disruption of BGLF2 in EBV led to more pronounced induction of ISGs. Our study unveils the roles of BGLF2 not only in the subversion of innate IFN response but also in lytic infection and reactivation of EBV. IMPORTANCE Epstein-Barr virus (EBV) is an oncogenic virus associated with the development of lymphoid and epithelial malignancies. EBV has to subvert interferon-mediated host antiviral response to replicate and cause diseases. It is therefore of great interest to identify and characterize interferon-antagonizing proteins produced by EBV. In this study, we perform a screen to search for EBV proteins that suppress the action of interferons. We further show that BGLF2 protein of EBV is particularly strong in this suppression. This is achieved by inhibiting two key proteins STAT1 and STAT2 that mediate the antiviral activity of interferons. BGLF2 recruits a host enzyme to remove the phosphate group from STAT1 thereby inactivating its activity. BGLF2 also redirects STAT2 for degradation. A recombinant virus in which BGLF2 gene has been disrupted can activate host interferon response more robustly. Our findings reveal a novel mechanism by which EBV BGLF2 protein suppresses interferon signaling.

Analysing Complex Oral Protein Samples: Complete Workflow and Case Analysis of Salivary Pellicles.

Studies on small quantity, highly complex protein samples, such as salivary pellicle, have been enabled by recent major technological and analytical breakthroughs. Advances in mass spectrometry-based computational proteomics such as Multidimensional Protein Identification Technology have allowed precise identification and quantification of complex protein samples on a proteome-wide scale, which has enabled the determination of corresponding genes and cellular functions at the protein level. The latter was achieved via protein-protein interaction mapping with Gene Ontology annotation. In recent years, the application of these technologies has broken various barriers in small-quantity-complex-protein research such as salivary pellicle. This review provides a concise summary of contemporary proteomic techniques contributing to (1) increased complex protein (up to hundreds) identification using minute sample sizes (µg level), (2) precise protein quantification by advanced stable isotope labelling or label-free approaches and (3) the emerging concepts and techniques regarding computational integration, such as the Gene Ontology Consortium and protein-protein interaction mapping. The latter integrates the structural, genomic, and biological context of proteins and genes to predict protein interactions and functional connections in a given biological context. The same technological breakthroughs and computational integration concepts can also be applied to other low-volume oral protein complexes such as gingival crevicular or peri-implant sulcular fluids.

Interaction of storage medium and silver diamine fluoride on demineralized dentin.

OBJECTIVE: The effects of saliva on demineralized dentin and silver diamine fluoride (SDF) were investigated in vitro. METHODS: Dentin samples stored in deionized water (DIW), buffer solution (BS), basal medium mucin (BMM), and unstimulated whole saliva (UWS) were demineralized for 3 days and immersed in the same storage media. SDF as a 38 mass% solution was applied to the dentin samples for 3 minutes after they had been replaced in their respective medium. Surfaces were analyzed by scanning electron microscopy, energy-dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). RESULTS: Scanning electron microscopy showed various surface deposits and coatings, including occlusion of dentinal tubules. DIW resulted in the thinnest coating, whereas BMM resulted in the thickest. EDX and XPS showed the formation of metallic silver and silver compounds in all four media, with the greatest formation in BS. XRD indicated that the main product was silver chloride except in DIW. Sulphur was found in BMM and UWS. EDX and XPS detected fluoride and XRD detected calcium fluoride and fluorohydroxyapatite in BS, BMM, and UWS. CONCLUSION: The interaction between SDF and demineralized dentin was dependent upon the storage medium. BMM provided an outcome most similar to human saliva.

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.

Differences in the bacteriome of swab, saliva, and tissue biopsies in oral cancer.

Microbial dysbiosis has been implicated in the pathogenesis of oral cancer. We analyzed the compositional and metabolic profile of the bacteriome in three specific niches in oral cancer patients along with controls using 16SrRNA sequencing (Illumina Miseq) and DADA2 software. We found major differences between patients and control subjects. Bacterial communities associated with the tumor surface and deep paired tumor tissue differed significantly. Tumor surfaces carried elevated abundances of taxa belonging to genera Porphyromonas, Enterobacteriae, Neisseria, Streptococcus and Fusobacteria, whereas Prevotella, Treponema, Sphingomonas, Meiothermus and Mycoplasma genera were significantly more abundant in deep tissue. The most abundant microbial metabolic pathways were those related to fatty-acid biosynthesis, carbon metabolism and amino-acid metabolism on the tumor surface: carbohydrate metabolism and organic polymer degradation were elevated in tumor tissues. The bacteriome of saliva from patients with oral cancer differed significantly from paired tumor tissue in terms of community structure, however remained similar at taxonomic and metabolic levels except for elevated abundances of Streptococcus, Lactobacillus and Bacteroides, and acetoin-biosynthesis, respectively. These shifts to a pro-inflammatory profile are consistent with other studies suggesting oncogenic properties. Importantly, selection of the principal source of microbial DNA is key to ensure reliable, reproducible and comparable results in microbiome studies.

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.

Reflection before and after clinical practice-Enhancing and broadening experience through self-, peer- and teacher-guided learning.

INTRODUCTION: This paper explores a novel pedagogy surrounding students' clinical practice sessions. Before each clinical session, student clinical groups meet and each student presents their treatment planned for that session. The teachers question their understanding and explore "what-if" and other management scenarios. Peers in the clinical group observe the presentation and learning dialogue. After the clinical session, students gather on the clinic to debrief their performance with the tutor. Peers observe this dialogue, the shared clinical experience. This paper explores students' perceptions of reflection before action and reflection on action surrounding their clinical practice. METHODS: Focus groups were conducted to explore this phenomenon and to create a questionnaire, which was administered to the whole class. Transcriptions of the focus groups and open-ended response in the questionnaire were subjected to a thematic analysis to identify emerging themes and supported by closed-ended question responses. RESULTS: Briefing sessions before clinical sessions helped students identify problems and clear doubts before entering clinics. Students were able to recall and rehearse the clinical procedural knowledge and felt well prepared and confident for patient care. Student sharing of knowledge with peers provided a broader learning experience and helped gain confidence. Students also reported to learn from the teacher facilitating their preparation for the session. Debriefing sessions after the clinical session allowed reflection and learning including error correction on their own and peer experiences. Students learnt personally, from peers and from the teacher, and emphasised the importance of the student-teacher relation. CONCLUSIONS: Briefing and debriefing sessions were highly valued by students for preparation and learning on clinics and in learning from peers. Briefing sessions cleared misunderstanding, prevented errors, broadened procedural knowledge and improved both confidence and clinical experience. Debriefing sessions facilitated reflective practice, error correction and prevention, and helped gain insights from teachers' own experience and perspectives.