A flipped classroom approach to teaching oral pathology using virtual microscopy - the Glasgow experience

This paper describes a student-centred, integrated teaching model in which oral pathology and oral medicine staff members jointly deliver tutorials in a combined online and face-to-face format. Students are provided with clinical and histopathological information, which they must review and use to answer questions via a Virtual Learning Environment before the tutorial takes place. By reviewing the students’ answers online before the teaching session, staff can focus the tutorial itself on resolving knowledge gaps and afterwards post a set of gold standard answers online for students to reflect upon. CPD/Clinical Relevance: This article illustrates a combination of teaching methods and modern technologies which integrate clinical with laboratory sciences and enhance the access of students to histopathological materials without the need for access to a traditional microscopy facility

Genetic typing of Candida albicans strains isolated from the oral cavity of patients with denture stomatitis before and after itraconazole therapy

This study determined, by molecular typing of C. albicans species isolated from denture stomatitis patients with a mycological relapse six months after successful itraconazole therapy, whether there had been recurrence of infection with the same strain(s), selection of particular strains or infection with new strains of C. albicans. Forty patients with long-standing Candida-associated denture stomatitis were assigned either cyclodextrin itraconazole solution or itraconazole capsules (100mg b.d. for 15 days). Palatal erythema was measured and imprint cultures undertaken at baseline and at 15 days, four weeks and six months after treatment commenced. Yeast isolates were formally identified and chromosomal DNA was extracted from pairs of isolates from those patients with C. albicans present at baseline and six months after treatment commenced. Southern blotting of EcoRI-digested chromosomal DNA was performed using the C. albicans-specific 27A repetitive element as a probe. Eighteen of 36 patients were infected with C. albicans at baseline and six months after treatment commenced. Overall, 13 genetically different strains of C. albicans were found. However, in 17 of 18 patients, the C. albicans strains isolated prior to itraconazole therapy and six months later were the same. Thus recurrence of denture stomatitis in these individuals was due to re-colonisation by the original strain, rather than re-infection with a different strain. Key words: Genotyping, C. albicans, denture stomatitis

Facilitation of student-staff partnership in development of digital learning tools through a special study module

A student-staff partnership was formed as part of a final year special study module to provide dental students the opportunity to work closely with faculty to produce high-quality e-learning resources in areas of the curriculum identified by the students as particularly difficult. The student-staff team identified the following themes as major influences on the success of the project: student-staff interaction, ownership, managing expectations, time pressures, and co-creation partnership benefits. This partnership resulted in a valuable learning experience for both the students and staff involved. The resource developed was evaluated by junior dental students in second and third year of the five year Bachelor of Dental Surgery (BDS) degree programme at Glasgow Dental School and showed a high degree of acceptability by those in both groups. The quality assurance built into the process has resulted in an e-learning resource that has been incorporated directly into our flipped classroom model for pre-clinical skills teaching

Evaluating Streptococcus mutans strain dependent characteristics in a polymicrobial biofilm community

Aim: The purpose of this study was to investigate strain dependent differences of the cariogenic biofilm forming Streptococcus mutans within both simple and complex communities. Methods: A mono-species containing representative S. mutans clinical isolates (caries and non-caries), and a multispecies in vitro caries biofilm model containing Lactobacillus casei, Veillonella dispar, Fusobacterium nucleatum and Actinomyces naeslundii, and either of two representative S. mutans clinical isolates (caries and non-caries), was developed as a comparison model. Compositional analysis of total and live bacteria within biofilms, and transcriptional analysis of biofilm associated virulence factors were evaluated by live/dead PCR and quantitative PCR, respectively. Scanning electron microscopy (SEM) was used to analyze the architecture of biofilm. One-way analysis of variance and t-tests were used to investigate significant differences between independent groups of data. Results: Within a mono-species biofilm, different S. mutans strains responded similarly to one another during biofilm formation in different carbohydrate sources, with sucrose showing the highest levels of biofilm biomass and galactose showing the lowest. Within the polymicrobial biofilm system, compositional analysis of the bacteria within the biofilm showed that S. mutans derived from a caries-free patient was preferentially composed of both total and viable L. casei, whereas S. mutans derived from a caries patient was dominated by both total and viable S. mutans (p < 0.001). Normalized gene expression analysis of srtA, gtfB, ftf, spaP, gbpB, and luxS, showed a general upregulation within the S. mutans dominant biofilm. Conclusion: We were able to demonstrate that individual strains derived from different patients exhibited altered biofilm characteristics, which were not obvious within a simple mono-species biofilm model. Influencing the environmental conditions changed the composition and functionality S. mutans within the polymicrobial biofilm. The biofilm model described herein provides a novel and reproducible method of assessing the impact on the biofilm microbiome upon different environmental influences

Use of safety syringes for administration of local anaesthesia among a sample of UK primary care dental professionals.

Aim: To identify the current usage of SSDs in UK primary care dentistry. Method: A cross-sectional survey was administered to delegates at the 2017 British Dental Association (BDA) Conference and Exhibition in Manchester, and at the 2017 BDA Scottish Conference and Exhibition in Glasgow. The survey covered a range of questions relating to sharps injuries and use of traditional and safety syringes for delivery of local anaesthesia. Statistical analyses were conducted using SPSS Version 22 (IBM Corp., 2013) and included chi-square and Fisher's exact tests. Results: Seven hundred and ninety-six delegates participated, of whom 396 (49.7%) were using safety syringes for delivery of local anaesthesia. Of the 166 participants who had experienced a sharps injury in the past year, 76 (45.8%) worked in facilities that most commonly used SSDs for delivery of local anaesthesia. Conclusion: Our results indicate that a significant number of dental practices in our sample have not adopted SSDs and suggest sharps injuries are still being sustained in some practices using SSDs. Further epidemiological research is required to provide strong evidence for the effectiveness of SSDs and reasons why SSDs have not been fully adopted in UK primary dental care

Identification of bacteria on the surface of clinically infected and non-infected prosthetic hip joints removed during revision arthroplasties by 16S rRNA gene sequencing and by microbiological culture

It has been postulated that bacteria attached to the surface of prosthetic hip joints can cause localised inflammation, resulting in failure of the replacement joint. However, diagnosis of infection is difficult with traditional microbiological culture methods, and evidence exists that highly fastidious or non-cultivable organisms have a role in implant infections. The purpose of this study was to use culture and culture-independent methods to detect the bacteria present on the surface of prosthetic hip joints removed during revision arthroplasties. Ten consecutive revisions were performed by two surgeons, which were all clinically and radiologically loose. Five of the hip replacement revision surgeries were performed because of clinical infections and five because of aseptic loosening. Preoperative and perioperative specimens were obtained from each patient and subjected to routine microbiological culture. The prostheses removed from each patient were subjected to mild ultrasonication to dislodge adherent bacteria, followed by aerobic and anaerobic microbiological culture. Bacterial DNA was extracted from each sonicate and the 16S rRNA gene was amplified with the universal primer pair 27f/1387r. All 10 specimens were positive for the presence of bacteria by both culture and PCR. PCR products were then cloned, organised into groups by RFLP analysis and one clone from each group was sequenced. Bacteria were identified by comparison of the 16S rRNA gene sequences obtained with those deposited in public access sequence databases. A total of 512 clones were analysed by RFLP analysis, of which 118 were sequenced. Culture methods identified species from the genera Leifsonia (54.3%), Staphylococcus (21.7%), Proteus (8.7%), Brevundimonas (6.5%), Salibacillus (4.3%), Methylobacterium (2.2%) and Zimmermannella (2.2%). Molecular detection methods identified a more diverse microflora. The predominant genus detected was Lysobacter, representing 312 (60.9%) of 512 clones analysed. In all, 28 phylotypes were identified: Lysobacter enzymogenes was the most abundant phylotype (31.4%), followed by Lysobacter sp. C3 (28.3%), gamma proteobacterium N4-7 (6.6%), Methylobacterium SM4 (4.7%) and Staphylococcus epidermidis (4.7%); 36 clones (7.0%) represented uncultivable phylotypes. We conclude that a diverse range of bacterial species are found within biofilms on the surface of clinically infected and non-infected prosthetic hip joints removed during revision arthroplasties

Antifungal, Cytotoxic, and Immunomodulatory Properties of Tea Tree Oil and Its Derivative Components: Potential Role in Management of Oral Candidosis in Cancer Patients

Candida albicans forms oral biofilms that cause disease and are difficult to treat with conventional antifungal agents. Tea tree oil (TTO) is a natural compound with reported antimicrobial and immunomodulatory activities. The aims of the study were to evaluate the antifungal efficacy of TTO and key derivatives against C. albicans biofilms, to assess the toxicological effects of TTO on a clinically relevant oral cell line, and to investigate its impact on inflammation. TTO and its derivatives were examined against 100 clinical strains of C. albicans. Planktonic minimum inhibitory concentrations (MICs) were determined using the CLSI M-27A broth microdilution method. Sessile MICs were determined using an XTT reduction assay. Inhibition, time-kill, and mode of action studies were performed. OKF6-TERT2 epithelial cells were used for cytotoxicity and cytokine expression assays. Planktonic C. albicans isolates were susceptible to TTO, terpinen-4-ol (T-4-ol), and α-terpineol, with an MIC50 of 0.5, 0.25, and 0.25%, respectively. These three compounds also displayed potent activity against the 69 biofilm-forming strains, of which T-4-ol and α-terpineol displayed rapid kill kinetics. For all three compounds, 1 × MIC50 effectively inhibited biofilm growth when C. albicans were treated at 0, 1, and 2 h post adhesion. By scanning electron microscopy analysis and PI uptake, TTO and derivative components were shown to be cell membrane active. TTO and T-4-ol were cytotoxic at 1 × MIC50, whereas at 0.5 × MIC50 T-4-ol displayed no significant toxicity. Transcript and protein analysis showed a reduction of IL-8 when treated with TTO and T-4-ol. These data provide further in vitro evidence that TTO and its derivative components, specifically T-4-ol, exhibit strong antimicrobial properties against fungal biofilms. T-4-ol has safety advantages over the complete essential oil and may be suitable for prophylaxis and treatment of established oropharyngeal candidosis. A clinical trial of T-4-ol is worthy of consideration

Assessing Malawi’s recent development of a National Oral Health Policy – learning for the future

# Background Policymakers in many low- and middle-income countries do not prioritize oral health and are inadequately informed about the burden of oral and maxillofacial problems, their connection with systemic health and the possible threat to human life. In Africa, the absence of oral health policies is a key problem contributing to increased oral disease burden, health workforce shortage, and inadequate oral health service provision. Context-relevant policies and research to determine needs and monitor progress are key components in eradicating oral health inequalities. This paper focuses on the work of Malawi to follow the direction of travel outlined at the 2021 World Health Assembly by developing its first National Oral Health Strategy and Implementation Plan. # Methods A case study approach examined the processes followed by Malawi to develop its National Oral Health Policy, launched in April 2022. The aim was to understand how oral health policy is being developed within the context of an African country. Specifically, the objectives were to identify how oral health policy was being developed in Malawi and the contributors to the development of that policy. Qualitative data were collected from semi-structured interviews (n=8) of purposively selected key informants from the Malawi National Oral Health Policy Taskforce team involved in the policy creation. Data were analyzed in the thematic areas within the Health Policy Triangle of actors, context, processes, and content. # Results The policy development process was guided by Malawi's Ministry of Health and involved a diverse group of actors, both local and international. The funding of the policy development process by the Scottish Government and Borrow Foundation provided critical support. Five groups of stakeholders have conducted the relevant background investigations and written the Oral Health Policy: international development partners, academics, policy experts, dental practitioners, and civil society organizations. The partnership skill-sharing and well-managed dynamics of the group, together with the reliable funding base, all contributed to a successful outcome. # Conclusions A multisectoral approach was used. Malawi is uniquely placed in its oral health policy development, having a solid stakeholder base (local and international) and resources to support the policy development and, partly, its implementation

Impact of frequency of denture cleaning on microbial and clinical parameters - a bench to chairside approach

Objective: Robust scientific and clinical evidence of how to appropriately manage denture plaque is lacking. This two-part study (i) developed an in vitro model of denture plaque removal, and (ii) assessed effectiveness of these approaches in a randomised clinical trial. Method: (i) a complex denture plaque model was developed using the dominant microbial genera from a recent microbiome analyses. Biofilms formed on polymethylmethacrylate were brushed daily with a wet toothbrush, then either treated daily for 5 days or only on Days 1 and 5 with Polident® denture cleanser tablets (3 min soaking). Quantitative and qualitative microbiological assessments were performed. (ii), an examiner-blind, randomised, crossover study of complete maxillary denture wearers was performed (n = 19). Either once-daily for 7 days or on Day 7 only, participants soaked dentures for 15 min using Corega® denture cleansing tables, then brushed. Denture plaque microbiological assessment used sterilized filter paper discs. Results: The in vitro model showed daily cleaning with denture cleanser plus brushing significantly reduced microbial numbers compared to intermittent denture cleaning with daily brushing (p < 0.001). The clinical component of the study showed a statistically significant reduction in denture plaque microbial numbers in favour of daily versus weekly treatment (aerobic bacteria p = 0.0144). Both in vitro and in vivo studies showed that denture plaque biofilm composition were affected by different treatment arms. Conclusions: This study demonstrated that daily denture cleansing regimens are superior to intermittent denture cleansing, and that cleansing regimens can induce denture plaque compositional changes. Clinicaltrials.gov registration: NCT02780661