Genomic Diversity among Actinomyces naeslundii Strains and Closely Related Species.

The aim of this study was to investigate and clarify the ambiguous taxonomy of Actinomyces naeslundii and its closely related species using state-of-the-art high-throughput sequencing techniques, and, furthermore, to determine whether sub-clusters identified within Actinomyces oris and Actinomyces naeslundii in a previous study by multi locus sequence typing (MLST) using concatenation of seven housekeeping genes should either be classified as subspecies or distinct species. The strains in this study were broadly classified under Actinomyces naeslundii group as A. naeslundii genospecies I and genospecies II. Based on MLST data analysis, these were further classified as A. oris and A. naeslundii. The whole genome sequencing of selected strains of A. oris (n = 17) and A. naeslundii (n = 19) was carried out using Illumina Genome Analyzer IIxe and Roche 454 allowing paired-end and single-reads sequencing, respectively. The sequences obtained were aligned using CLC Genomic workbench version 5.1 and annotated using RAST (Rapid Annotation using Subsystem Technology) release version 59 accessible online. Additionally, genomes of seven publicly available strains of Actinomyces (k20, MG1, c505, OT175, OT171, OT170, and A. johnsonii) were also included. Comparative genomic analysis (CGA) using Mauve, Progressive Mauve, gene-by-gene, Core, and Pan Genome, and finally Digital DNA-DNA homology (DDH) analysis was carried out. DDH values were obtained using in silico genome-genome comparison. Evolutionary analysis using ClonalFrame was also undertaken. The mutation and recombination events were compared using chi-square test among A. oris and A. naeslundii isolates (analysis methods are not included in the study). CGA results were consistent with previous traditional classification using MLST. It was found that strains of Actinomyces k20, MG1, c505, and OT175 clustered in A. oris group of isolates, while OT171, OT170, and A. johnsonii appeared as separate branches. Similar clustering to MLST was observed for other isolates. The mutation and recombination events were significantly higher in A. oris than A. naeslundii, highlighting the diversity of A. oris strains in the oral cavity. These findings suggest that A. oris forms six distinct groups, whereas A. naeslundii forms three. The correct designation of isolates will help in the identification of clinical Actinomyces isolates found in dental plaque. Easily accessible online genomic sequence data will also accelerate the investigation of the biochemical characterisation and pathogenesis of this important group of micro-organisms.

The perceptions and attitudes of qualified dental therapists towards a diagnostic role in the provision of paediatric dental care.

Objectives This study explored the perceptions and attitudes of qualified UK dental therapists (DTs) to act in a diagnostic role in the dental care of paediatric patients.Methods A mixed methods study. An electronic questionnaire was sent out to the members of associations and closed social networking groups for qualified DTs across the UK. The questionnaire explored the training, clinical experience and working practices of the participants and measured their agreements with applicable statements using Likert scale scores. Semi-structured interviews were also undertaken to explore how UK DTs perceived a diagnostic role for them and what barriers and facilitators they experienced.Results A total of 155 questionnaire responses were returned and 11 interviews conducted. Participants were mostly women (94.8%) with a broad range of working experience, with a mean experience of 9.5 years (± 8.8 standard deviation [SD]) (range: 1-42 years). From the questionnaires, when asked to score agreement on a Likert scale from 0-5, DTs agreed that in a diagnostic role, they could increase access to dentistry for patients and a high proportion were in agreement that they had the knowledge to carry out examination (mean = 4.43 ± 0.87 SD), diagnosis (mean = 4.37 ± 0.90 SD) and care planning for paediatric patients (mean = 2.74 ± 1.32 SD). The interviews yielded three qualitative supra themes: 'working in the UK as a DT today'; 'the perceptions of dental therapists on acting in a diagnostic role in paediatric dental care'; and 'barriers and facilitators to acting in a diagnostic role' and within these, eight major themes were identified.Conclusion Within the limitations of a small sample who were representative of the workforce demographic and educational structures, we found that DTs felt that if they were to act in a diagnostic role, it would improve access to dental services benefitting patients, dentists and the DT profession. DTs identified and explored barriers and facilitators to a diagnostic role. Change is required to overcome these barriers in order to support DTs to act in a front-line diagnostic role.

Teaching of gerodontology to dental and dental hygiene therapy students in the UK.

Introduction The demographic shift in the age profile of the UK is now well established. Older people have more complex requirements to maintain their oral health and appropriate training is required to provide good-quality oral and dental care. This research aimed to review the training in gerodontology currently being provided to undergraduate dental and dental hygiene therapy (DHT) students in the UK.Methods Quantitative data were generated through completion of an online questionnaire, emailed to the directors of dental education in each of the UK dental (n = 16) and DHT schools (n = 21). Data were analysed using IBM SPSS Statistics V26.Results There was a response rate of 37.5% from dental schools and 61.9% from DHT schools. Although gerodontology was being taught in every school that responded, it was only a standalone course in 16.7% of dental schools and 7.7% of DHT schools that responded. While all respondents reported a theoretical component, only 50% of dental schools and 53.8% of DHT schools reported providing clinical experience. Moreover, 33.3% of dental schools and 15.4% of DHT schools reported closely following the European curriculum guidelines in gerodontology.Conclusions The current training in gerodontology is not standardised across either dental or DHT schools in the UK and there seems to be a lack of awareness of the recommended European guidelines. The findings from this research demonstrate that future improvements in gerodontology training are still required for this to be achieved.

Insignia of the Royal Army Dental Corps and Commonwealth Dental Corps.

The insignia worn by the British and Commonwealth Armed Services are rich in symbolism and meaning to the corps and regiments that wear them. Originally, before the adoption of national uniforms pre-1700s, there was little to distinguish friend from foe. To overcome that problem, certainly in battle, it was common practice to wear some sort of distinctive emblem, such as a sprig of a native plant. This then developed, in the reign of Charles II, to the custom of individual regiments or corps adopting devices and designs of their 'colours', through to modern cap and collar badges.On the centenary of the Royal Army Dental Corps, this paper gives some insight into those designs adopted by the Royal and Commonwealth Dental Corps, when a distinct service of dental care was recognised. They give a fascinating insight into the adoption and amalgamation of both national and dental symbols. The Dental Corps, separate from Army Medical Corps, went on to develop the vital provision of dental healthcare, both in the field and at home.

Potential educational and workforce strategies to meet the oral health challenges of an increasingly older population: a qualitative study.

INTRODUCTION: The demographic shift in the age profile of the UK is well established. Older people have more complex requirements to maintain their oral health. OBJECTIVES: This research explored Gerodontology with influential and recognised UK experts in Dental Public Health, Dental Education and Gerodontology. Three main topics were explored: the dental challenges associated with the ageing population, the role of dental care professionals (DCPs) and the training of undergraduate dental professionals. METHODS: Quantitative data from the literature were used to develop a topic guide for semi-structured interviews with a purposeful sample of nine participants. Initial analysis of the qualitative data was undertaken using NVivo V12 software and themes were identified. Final themes and subthemes were confirmed after a series of remote round table discussions. RESULTS: Four themes and 14 subthemes were identified. These included disagreements and agreements, the challenges of providing dental care to the older adult population, and the delivery of dental care by the dental team and finally education. All participants had significant concerns about the oral and dental challenges of the older population. CONCLUSIONS: The themes that emerged were complex and overlapping. Better utilisation of all members of the dental workforce was reported to be an essential approach, as was reorientation of existing care models with a focus on prevention. Regarding undergraduate education, the consensus was that the training was not adequate for both current and future needs.

Accreditation and professional integration experiences of internationally qualified dentists working in the United Kingdom.

INTRODUCTION: Regulatory processes for Oral health care professionals are considered essential for patient safety and to ensure health workforce quality. The global variation in their registration and regulation is under-reported in the literature. Regulatory systems could become a barrier to their national and international movement, leading to loss of skilled human resources. The General Dental Council is the regulatory authority in the UK, one of the nine regulators of health care overseen by the Professional Standards Authority. AIM: The aim of this paper is to present the professional integration experiences of internationally qualified dentists (IQDs) working in the UK, against the background of regulation and accreditation nationally. METHODS: Registration data were obtained from the General Dental Council to inform the sampling and recruitment of research participants. Semi-structured interviews of 38 internationally qualified dentists working in the United Kingdom were conducted between August 2014 and October 2017. The topic guide which explored professional integration experiences of the dentists was informed by the literature, with new themes added inductively. A phenomenological approach involving an epistemological stance of interpretivism, was used with framework analysis to detect themes. RESULTS: Internationally qualified dentist's professional integration was influenced by factors that could be broadly classified as structural (source country training; registration and employment; variation in practising dentistry) and relational (experiences of discrimination; value of networks and support; and personal attributes). The routes to register for work as a dentist were perceived to favour UK dental graduates and those qualifying from the European Economic Area. Dentists from the rest of the world reported experiencing major hurdles including succeeding in the licensing examinations, English tests, proving immigration status and succeeding in obtaining a National Health Service performer number, all prior to being able to practice within state funded dental care. CONCLUSION: The pathways for dentists to register and work in state funded dental care in UK differ by geographic type of registrant, creating significant inconsistencies in their professional integration. Professional integration is perceived by an individual IQD as a continuum dictated by host countries health care systems, workforce recruitment policies, access to training, together with their professional and personal skills. The reliance of the UK on internationally qualified dentists has increased in the past two decades, however, it is not known how these trends will be affected by UK's exit from the European Union and the COVID-19 pandemic.

Migration, Retention and Return Migration of Health Professionals Comment on "Doctor Retention: A Cross-sectional Study of How Ireland Has Been Losing the Battle".

Medical education and training of health professionals are linked with their recruitment and retention. Practising as a competent health professional requires life-long continuous training and therefore training structures in health systems appear to influence doctors job satisfaction, their well-being and their intentions to remain in that health system. The commentary critiques aspects of the paper on doctors retention in Ireland, while drawing some parallels with the United Kingdom. There appears to be an emerging type of health professional migrants 'education tourists' who travel to other countries to obtain medical education creating new routes of migration and this presents new challenges to source and destination countries. The global shortage of doctors and other health professionals further exacerbates health inequalities as seen in the present pandemic and therefore the increased need for research into health professionals' migration and their integration.

Profiles of registrant dentists and policy directions from 2000 to 2020.

INTRODUCTION: The National Health Service's reliance on overseas doctors and nurses, unlike dentists, has been widely reported. As the United Kingdom (UK) leaves the European Union, an understanding of the migration trends and possible influences are important to inform future planning. AIM: To examine trends in the profile of UK registered dentists in the context of key events and policy changes from 2000 to 2020. METHOD: Data were obtained from the General Dental Council via annual reports, and under 'freedom of information' communications; details of policy initiatives were obtained from the government and professional websites. RESULTS: Over a 20-year period (2000-2019), the number of registered dentists increased from 31,325 to 42,469, a net increase of 36% (11,144 dentists), the majority of whom were international graduates (58%; n = 6,416) such that by December 2019, 28% of all registered dentists had qualified outside of the UK. Similarly, regarding new registrants, there were increases of graduates from UK (18%), EEA countries (214%) and, via the Overseas Registration Examination route (621%); and a decrease from countries with bilateral agreements for recognition (43%), in line with changes in health and immigration policies. CONCLUSIONS: International dental graduates increasingly contribute to the UK dental workforce and there is an urgent need for research into dentist migration and retention in the UK in support of patient access to dental care. IMPACT: The United Kingdom (UK) dental workforce is increasingly reliant on international dental graduates representing 28% of current registrants compared with 18% in 2000. Health policies and immigration policies were the main drivers that influenced dental workforce migration to the UK along with wider events, such as EU expansions, global recession and Brexit. Pre-existing lack of research into dental workforce could add to the uncertainties of post COVID-19 oral health care access and delivery.

Research dissertation to published paper: the journey to a successful publication.

Background Many dental professionals are now completing higher degrees that involve a research project. However, many of those research projects, although worthwhile, are not written up for publication in a peer-reviewed journal.Aim To encourage and assist novice authors in transferring their project report into a paper to submit for publication.Discussion The relationship between the authors and contributors is considered, and advice is given on how to focus on the specific research question and produce a succinct paper within the target journal's word limit. Emphasis is placed on choosing the right journal for submission and the need to follow the 'instructions to authors', as well as what happens post-submission, post-acceptance and post-publication. Furthermore, some of the difficulties that the authors have encountered on their own publication journeys are highlighted.Conclusion Great satisfaction will be derived if the novice researcher makes the most of their opportunity of undertaking a research project and subsequently getting it published in a peer-reviewed journal. Publishing gives the author recognition within their professional community, a feeling of personal achievement, can create better career perspectives and allows others to build on the work.

#Teeth&Tweets: the reach and reaction of an online social media oral health promotion campaign.

Aim The aim of the study was to investigate: i) the geographical reach and reaction of the online participants engaging in an oral health campaign 'National Smile Month' UK 2016 (NSM); and ii) whether dental practices during NSM were using Twitter to help address regional oral health inequalities.Methods Twitter posts, that is 'tweets', were collected using the application programming interface (API) software Mozdeh, for one month. Tweets were classified into high, medium or low engagement. Participants' postcode data of the organisation/practice were obtained via an internet search using Google. The geolocation of tweets was then linked by organisations' postcode to the 2015 Index of Multiple Deprivation and the oral health survey of five-year-olds 2014/15, and subsequently mapped using Google Fusion Tables.Results A total of 23,100 tweets were captured with a final total of 2,968 usable tweets from 763 separate accounts. Two hundred and twelve tweets were from dental practices, with 107 classified as low engagement, 99 medium, and 45 high engagement (39 of those tweets were from organisations allied to oral health). Interactive maps were created to give a visual representation of the relationship between those participants producing 'high' impact tweets and the level of dental decay in five-year-olds and deprivation levels.Conclusion The majority of tweets did not promote any specific preventative behaviour. Dental practices in England were not contributing to National Smile Month via Twitter in a way that would improve regional oral health inequalities. In areas of high-need there is evidence of proactive engagement with NSM via Twitter by local authorities and their healthcare partners.

Should mentoring be routinely introduced into general dental practice to reduce the risk of occupational stress?

Introduction Occupational stress within general dental practice can potentially have an adverse impact on a practitioner's wellbeing and the quality of healthcare provided by that individual. Mentoring has routinely been utilised in other professions for stress management, however, there is little in the dental literature discussing the benefits of mentorship on the reduction of occupational stress for dental practitioners.Aim The aim of this study was to explore the perceptions of experienced foundation dental trainers within the Health Education, Kent, Surrey and Sussex postgraduate deanery as to the usefulness of routine mentoring as a tool to reduce occupational stress.Methods Using a qualitative approach, six individual semi-structured interviews were undertaken. Recorded interviews were transcribed and transcriptions were analysed using thematic coding to identify overarching themes.Results Both similarities and differences with the existing literature on routine mentoring within professional settings were identified. Foundation dental trainers were positive towards the concept of routine mentoring, although there was also a degree of scepticism regarding the potential uptake among colleagues. There was a perception that mentoring might more practically be used as a reactionary tool. Multiple potential barriers to routine mentoring were identified, included funding, scheduling and a lack of training.Conclusions The analysis identified that currently, experienced foundation dental practitioners do not consider routine mentoring as a practical option in the prevention of occupational stress. The results would suggest that further education is required as to the benefits of routine mentoring as a strategy for occupational stress management. However, with additional resources buying time, a hybrid model of mentoring and coaching has significant potential in general dental practice.

Electronic primary dental care records in research: A case study of validation and quality assurance strategies.

BACKGROUND: In dentistry, the use of electronic patient records for research is underexplored. The aim of this paper is to describe a case study process of obtaining research data (sociodemographic, clinical and workforce) from electronic primary care dental records, and outlining data cleaning and validation strategies. This study was undertaken at the University of Portsmouth Dental Academy (UPDA), which is a centre of education, training and provision of state funded services (National Health Services). UPDA's electronic patient management system is R4/Clinical +. This is a widely used system in general dental practices in the UK. METHOD: A two-phase process, involving first Pilot and second Main data extraction were undertaken. Using System Query Language (SQL), data extracts containing variables related to patients' demography, socio-economic status and dental care received were generated. A data cleaning and validation exercise followed, using a combination of techniques including Maletic and Marcus's (2000) general framework for data cleaning and Rahm and Haido's (2010) principles of data cleaning. RESULTS: The findings of the case study support the use of a two-phase data extraction process. The data validation processes highlighted the need for both manual and analytical strategies when cleaning these data. Finally, the process demonstrated that electronic dental records can be validated and used for epidemiological and heath service research. The potential to generalise findings is great due to the large number of records. There are, however, limitations to the data which need to be considered, relating to quality (data input), database structure and interpretation of data codes. CONCLUSION: Electronic dental records are useful in health service research, epidemiological studies and skill mix research. Researchers should work closely with clinicians, managers and software developers to ensure that the data generated are accurate, valid and generalisable. Following data extraction the researchers need to adapt stringent validation and data cleaning strategies to guarantee that the extracted electronic data are accurate.

Bouncing on the fringes of the dental system: clinical dental technicians, a decade after their creation.

Aim To investigate clinical dental technicians' (CDTs) current working practices and their perception as registered dental professionals regarding their practice of dentistry, role and relationships in the dental team and within the UK healthcare system.Methods A postal questionnaire was sent to all 304 CDTs registered with the United Kingdom General Dental Council in September 2015, which included an information sheet and a consent form. Data were entered onto a computer and analysed using SPSS and free text responses were analysed using thematic analysis.Results A response rate of 37.8% was achieved. The majority of participants were male (93%), based in England (83%), working full time (66.4%), in the private sector (89.4%) and spending up to 50% of their time working as a CDT carrying out clinical work. CDTs reported barriers to their progression being the lack of an NHS contract and their limited scope of practice, which they wished to have extended to further their skill set and include direct access to provide partial dentures without a dentist's prescription.Conclusion There was some evidence that CDTs are becoming more recognised and valued members of the dental team. While CDTs felt they had progressed since their establishment in 2007, the respondents considered there was still a need for progress to be made towards integration within the dental system and recognition by the public. CDTs wished to see changes to their performer status and to have a wider scope of practice. The majority of CDTs work in the private sector, thus there is a need to explore their future roles within the state dental provision.

Migration motives and integration of international human resources of health in the United Kingdom: systematic review and meta-synthesis of qualitative studies using framework analysis.

OBJECTIVE: The aim of this review was to examine the migration motives, the barriers to and facilitators of integration of international dental graduates, compared with nurses and doctors in the United Kingdom. METHODS: Electronic databases Ovid MEDLINE, EMBASE, PubMed, Web of Knowledge and OECD publications were systematically searched for English language publications from January 2000 to January 2017. A total of 31 qualitative studies were selected and quality appraised and meta-synthesis of the qualitative data was carried out using framework synthesis. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were applied to present the findings. RESULTS: There were no studies on migration motives and one study on integration experiences of international dentists in the UK. The nursing literature had the highest volume and quality of evidence on nursing workforce, whilst there was limited literature on international doctors in the UK. Migration of health professionals to the UK is determined by personal and professional factors, together with source country-specific and UK drivers. Active recruitment, post graduate training and financial gain act as strong common macro, meso and micro drivers that perpetuate migration into the UK, but the extent to which each of these drivers influence nurses' and doctors' migration is different. Integration experiences for international nurses and doctors differed based on their source country experiences and the work environment they entered. Nurses reported a wider knowledge and skills gap, more multi-level discrimination and less career progression compared to the doctors. The migrants' integration experiences depend on their cultural awareness, discrimination exposure, English language and communication skills, social and professional support networks, social integration and personal attributes. CONCLUSION: Migration of international health professionals is motivated by macro, meso and micro drivers at the international, national, professional and personal levels. The UK has strong common macro pull factors which attract nurses, doctors and dentists and may impact on the effectiveness of policies to restrict their migration. The integration experiences of nurses and doctors differ and further research is required to understand the integration experiences of dentists, in order to retain these professionals by tailoring policies to each of these professions.

Dental Treatment in a State-Funded Primary Dental Care Facility: Contextual and Individual Predictors of Treatment Need?

OBJECTIVE: This study examined individual and contextual factors which predict the dental care received by patients in a state-funded primary dental care training facility in England. METHODS: Routine clinical and demographic data were extracted from a live dental patient management system in a state-funded facility using novel methods. The data, spanning a four-year period [2008-2012] were cleaned, validated, linked by means of postcode to deprivation status, and analysed to identify factors which predict dental treatment need. The predictive relationship between patients' individual characteristics (demography, smoking, payment status) and contextual experience (deprivation based on area of residence), with common dental treatments received was examined using unadjusted analysis and adjusted logistic regression. Additionally, multilevel modelling was used to establish the isolated influence of area of residence on treatments. RESULTS: Data on 6,351 dental patients extracted comprised of 147,417 treatment procedures delivered across 10,371 courses of care. Individual level factors associated with the treatments were age, sex, payment exemption and smoking status and deprivation associated with area of residence was a contextual predictor of treatment. More than 50% of children (<18 years) and older adults (≥65 years) received preventive care in the form of 'instruction and advice', compared with 46% of working age adults (18-64 years); p = 0.001. The odds of receiving treatment increased with each increasing year of age amongst adults (p = 0.001): 'partial dentures' (7%); 'scale and polish' (3.7%); 'tooth extraction' (3%; p = 0.001), and 'instruction and advice' (3%; p = 0.001). Smokers had a higher likelihood of receiving all treatments; and were notably over four times more likely to receive 'instruction and advice' than non-smokers (OR 4.124; 95% CI: 3.088-5.508; p = 0.01). A further new finding from the multilevel models was a significant difference in treatment related to area of residence; adults from the most deprived quintile were more likely to receive 'tooth extraction' when compared with least deprived, and less likely to receive preventive 'instruction and advice' (p = 0.01). CONCLUSION: This is the first study to model patient management data from a state-funded dental service and show that individual and contextual factors predict common treatments received. Implications of this research include the importance of making provision for our aging population and ensuring that preventative care is available to all. Further research is required to explain the interaction of organisational and system policies, practitioner and patient perspectives on care and, thus, inform effective commissioning and provision of dental services.

Alternative scenarios: harnessing mid-level providers and evidence-based practice in primary dental care in England through operational research.

BACKGROUND: In primary care dentistry, strategies to reconfigure the traditional boundaries of various dental professional groups by task sharing and role substitution have been encouraged in order to meet changing oral health needs. AIM: The aim of this research was to investigate the potential for skill mix use in primary dental care in England based on the undergraduate training experience in a primary care team training centre for dentists and mid-level dental providers. METHODS: An operational research model and four alternative scenarios to test the potential for skill mix use in primary care in England were developed, informed by the model of care at a primary dental care training centre in the south of England, professional policy including scope of practice and contemporary evidence-based preventative practice. The model was developed in Excel and drew on published national timings and salary costs. The scenarios included the following: "No Skill Mix", "Minimal Direct Access", "More Prevention" and "Maximum Delegation". The scenario outputs comprised clinical time, workforce numbers and salary costs required for state-funded primary dental care in England. RESULTS: The operational research model suggested that 73% of clinical time in England's state-funded primary dental care in 2011/12 was spent on tasks that may be delegated to dental care professionals (DCPs), and 45- to 54-year-old patients received the most clinical time overall. Using estimated National Health Service (NHS) clinical working patterns, the model suggested alternative NHS workforce numbers and salary costs to meet the dental demand based on each developed scenario. For scenario 1:"No Skill Mix", the dentist-only scenario, 81% of the dentists currently registered in England would be required to participate. In scenario 2: "Minimal Direct Access", where 70% of examinations were delegated and the primary care training centre delegation patterns for other treatments were practised, 40% of registered dentists and eight times the number of dental therapists currently registered would be required; this would save 38% of current salary costs cf. "No Skill Mix". Scenario 3: "More Prevention", that is, the current model with no direct access and increasing fluoride varnish from 13.1% to 50% and maintaining the same model of delegation as scenario 2 for other care, would require 57% of registered dentists and 4.7 times the number of dental therapists. It would achieve a 1% salary cost saving cf. "No Skill Mix". Scenario 4 "Maximum Delegation" where all care within dental therapists' jurisdiction is delegated at 100%, together with 50% of restorations and radiographs, suggested that only 30% of registered dentists would be required and 10 times the number of dental therapists registered; this scenario would achieve a 52% salary cost saving cf. "No Skill Mix". CONCLUSION: Alternative scenarios based on wider expressed treatment need in national primary dental care in England, changing regulations on the scope of practice and increased evidence-based preventive practice suggest that the majority of care in primary dental practice may be delegated to dental therapists, and there is potential time and salary cost saving if the majority of diagnostic tasks and prevention are delegated. However, this would require an increase in trained DCPs, including role enhancement, as part of rebalancing the dental workforce.

Investigation of retentive force reduction and wear of the locator attachment system with different implant angulations.

PURPOSE: To evaluate the effect of cyclic disengagement on the retentive force and wear patterns of pairs of three Locator inserts (blue, pink, and clear) in vitro. MATERIALS AND METHODS: Implant analogs (Astra Tech) were positioned into aluminum blocks parallel to each other and perpendicular to the horizontal plane, with one analog angulated mesially by 10 degrees (0/10), or with two implant analogs each angulated mesially by 5 degrees (5/5). Ninety Locator attachments, in 15 pairs of each standard retention strength (blue, pink, and clear), underwent 2,500 cycles of testing, lubricated with artificial saliva. Data were analyzed after 6, 12, and 18 months of simulated clinical use (720, 1,440, or 2,160 cycles). The wear patterns of the Locator inserts were examined before and after the cyclic dislodgments using scanning electron microscopy. RESULTS: There were significant differences in retentive force between clear, blue, and pink inserts at baseline, with the clear insert being the most retentive in the 0/10 model. The lowest percentage reduction in retentive force from baseline to 2,160 cycles was the pink insert in the 0/10 model, and the highest was the blue insert in the 5/5 angled model. CONCLUSION: A rapid decrease in retentive force was observed in all three models after 720 cycles for all three inserts. The most retentive combination was the clear insert in the 0/10 model, and the least retentive was the blue insert in the 0/10 model. After 2,160 cycles, there was a significant reduction in retentive force of 59% to 70%. However, the values of retention were still higher than those claimed by the manufacturer.

Dental skill mix: a cross-sectional analysis of delegation practices between dental and dental hygiene-therapy students involved in team training in the South of England.

BACKGROUND: Research suggests that health professionals who have trained together have a better understanding of one another's scope of practice and are thus equipped for teamwork during their professional careers. Dental hygiene-therapists (DHTs) are mid-level providers that can deliver routine care working alongside dentists. This study examines patterns of delegation (selected tasks and patients) by dental students to DHT students training together in an integrated team. METHODS: A retrospective sample of patient data (n = 2,063) was extracted from a patient management system showing the treatment activities of two student cohorts (dental and DHT) involved in team training in a primary care setting in the South of England over two academic years. The data extracted included key procedures delegated by dental students to DHT students coded by skill-mix of operator (e.g., fissure sealants, restorations, paediatric extractions) and patient demography. χ2 tests were conducted to investigate the relationship between delegation and patient age group, gender, smoking status, payment-exemption status, and social deprivation. RESULTS: A total of 2,063 patients managed during this period received treatments that could be undertaken by either student type; in total, they received 14,996 treatment procedures. The treatments most commonly delegated were fissure sealants (90%) and restorations (51%); whilst the least delegated were paediatric extractions (2%). Over half of these patients (55%) had at least one instance of delegation from a dental to a DHT student. Associations were found between delegation and patient age group and smoking status (P <0.001). Children under 18 years old had a higher level of delegation (86%) compared with adults of working age (50%) and patients aged 65 years and over (56%). A higher proportion of smokers had been delegated compared with non-smokers (45% cf. 26%; P <0.001). CONCLUSIONS: The findings suggest that delegation of care to DHT students training as a team with dental students, involved significantly greater experience in treating children and adult smokers, and providing preventive rather than invasive care in this integrated educational and primary care setting. The implications for their contribution to dentistry and the dental team are discussed, along with recommendations for primary care data recording.

Three-dimensional processing deformation of three denture base materials.

STATEMENT OF PROBLEM: Heat-polymerized polymethyl methacrylate denture bases deform during and after polymerization, and this deformation may affect the clinical performance of complete dentures. PURPOSE: The purpose of this study was to investigate the processing deformation of 3 denture base materials on a standardized anatomic model by using a contact scanner and surface matching software. MATERIAL AND METHODS: Maxillary reproductions of a definitive cast were digitized by using a contact scanner. The casts were allocated to 4 groups, depending on the denture base material: compression molded (heat polymerized, polymethyl methacrylate based); injection molded (heat polymerized, polymethyl methacrylate based); manually adapted and light-polymerized (urethane dimethacrylate based); and manually adapted, compression molded, and light-polymerized (urethane dimethacrylate-based). The intaglio surfaces of denture bases fabricated on each replicate cast also were digitized by using the contact scanner. Surface-matching software was used to measure dimensional changes between each cast and its corresponding denture base. The Kruskal-Wallis analysis of variance based on ranks was used to assess differences in contraction, expansion, and overall change among groups. The Mann-Whitney U test was performed to determine differences among individual groups. Statistical significance was inferred when P<.01 to compensate for multiple group comparisons. RESULTS: Statistically significant differences in processing deformations were observed among polymethyl methacrylate-based resins and urethane dimethacrylate-based resin. No differences were observed between compression molding and injection molding or between manual adaptation alone and the combination of manual adaptation and compression molding. CONCLUSIONS: Urethane dimethacrylate-based resin showed greater processing deformation compared with polymethyl methacrylate-based resins. Compression molding and injection molding techniques produced similar results for the polymethyl methacrylate-based resins. The methodology used showed patterns of deformation that were too complex to be accurately analyzed by linear measurements.

Application of MLST and pilus gene sequence comparisons to investigate the population structures of Actinomyces naeslundii and Actinomyces oris.

Actinomyces naeslundii and Actinomyces oris are members of the oral biofilm. Their identification using 16S rRNA sequencing is problematic and better achieved by comparison of metG partial sequences. A. oris is more abundant and more frequently isolated than A. naeslundii. We used a multi-locus sequence typing approach to investigate the genotypic diversity of these species and assigned A. naeslundii (n = 37) and A. oris (n = 68) isolates to 32 and 68 sequence types (ST), respectively. Neighbor-joining and ClonalFrame dendrograms derived from the concatenated partial sequences of 7 house-keeping genes identified at least 4 significant subclusters within A. oris and 3 within A. naeslundii. The strain collection we had investigated was an under-representation of the total population since at least 3 STs composed of single strains may represent discrete clusters of strains not well represented in the collection. The integrity of these sub-clusters was supported by the sequence analysis of fimP and fimA, genes coding for the type 1 and 2 fimbriae, respectively. An A. naeslundii subcluster was identified with both fimA and fimP genes and these strains were able to bind to MUC7 and statherin while all other A. naeslundii strains possessed only fimA and did not bind to statherin. An A. oris subcluster harboured a fimA gene similar to that of Actinomyces odontolyticus but no detectable fimP failed to bind significantly to either MUC7 or statherin. These data are evidence of extensive genotypic and phenotypic diversity within the species A. oris and A. naeslundii but the status of the subclusters identified here will require genome comparisons before their phylogenic position can be unequivocally established.