Prominin-1 controls stem cell activation by orchestrating ciliary dynamics.

Proper temporal and spatial activation of stem cells relies on highly coordinated cell signaling. The primary cilium is the sensory organelle that is responsible for transmitting extracellular signals into a cell. Primary cilium size, architecture, and assembly-disassembly dynamics are under rigid cell cycle-dependent control. Using mouse incisor tooth epithelia as a model, we show that ciliary dynamics in stem cells require the proper functions of a cholesterol-binding membrane glycoprotein, Prominin-1 (Prom1/CD133), which controls sequential recruitment of ciliary membrane components, histone deacetylase, and transcription factors. Nuclear translocation of Prom1 and these molecules is particularly evident in transit amplifying cells, the immediate derivatives of stem cells. The absence of Prom1 impairs ciliary dynamics and abolishes the growth stimulation effects of sonic hedgehog (SHH) treatment, resulting in the disruption of stem cell quiescence maintenance and activation. We propose that Prom1 is a key regulator ensuring appropriate response of stem cells to extracellular signals, with important implications for development, regeneration, and diseases.

Transfer of basic science knowledge in a problem-based learning curriculum.

AIM: The aim of this study was to evaluate transfer of basic science knowledge for clinical application in our BDS programme by exploring the correlations between student performance in integrated dental science (IDS) examinations and applied dental knowledge (ADK) tests. METHODS: Numeric test scores were drawn from summative IDS and ADK assessments undertaken by BDS students spanning six academic years (2013-14 to 2018-19) for two cohorts (2013 and 2014). The data included a total of 13 test scores for each cohort with four IDS tests, taken in Years 1 and 2, and nine ADK tests taken in Years 3, 4 and 5. RESULTS: The sample included 120 students across both cohorts with 65 females (54%) and 55 males (46%). The correlation coefficients between the successive tests and the combinations of IDS and ADK scores were positive, all being greater than 0.48, and all being significantly correlated (P < .001). Regarding correlation between standardised averages across all IDS tests and all ADK tests, performance remained significantly correlated: (2013 cohort: r (53) = .667, P < .001; 2014 cohort: r (50) = .700, P < .001). CONCLUSIONS: The results of this study show that the students' knowledge of basic sciences correlates with their applied dental knowledge and may offer a predictive value. These findings may be attributed to a PBL curriculum and student-led learning at our school.

How does dyslexia impact on the educational experiences of healthcare students? A qualitative study.

AIMS: To explore the impact of dyslexia on the educational experiences of undergraduate students in medicine, dentistry, dental therapy and biomedical sciences. METHODS: It was a qualitative study based on semi-structured interviews. The study was conducted at the Faculty of Medicine and Dentistry at a University in the South West region of the United Kingdom. Purposive sampling was used, and the participants included undergraduate students from the schools of medicine, dentistry and biomedical sciences. RESULTS: The sample consisted of fifteen undergraduate students including five from medicine; four from dentistry; three from dental therapy; and three from biomedical sciences. All students had a formal diagnosis of Dyslexia. The students shared their views and experiences regarding disclosure, transition into the university, learning environments, assessments and challenges after graduation. CONCLUSIONS: This is the first study to explore the impact of dyslexia on the educational experiences of healthcare students from multiple programmes in a variety of educational settings. The findings show that the students were confident regarding disclosure of their dyslexia and had a formal diagnosis of dyslexia established during their school years. Although the participants experienced typical academic difficulties associated with dyslexia, problem-based learning (PBL) was perceived to be enjoyable and less stressful than traditional lectures and no specific challenges were reported in acquisition of clinical, communication and team-working skills.

To accept or decline academic remediation: What difference does it make?

Introduction: Academic remediation offered after failure in a knowledge-based progress-test assessment is voluntary and involves student-centered individualized support that helps students to learn most effectively for themselves. This paper explores whether accepting or declining the offer of academic remediation given to struggling students impacts their outcomes both short-term and longitudinally. Method: Data was collated from 2015-16, 2016-17, and 2017-18 and included all students offered academic remediation in the third, fourth, and fifth years of a five-year Dentistry program. Z-scores for each stage and test were calculated and centered on a triggering point; the point at which the offer of remediation was made. These students' average performance post-trigger test and longitudinal performance were analyzed. Results: While performance for both groups significantly improved for the immediate post-trigger test after academic remediation, those that accepted remediation sustained longitudinal improvements across subsequent tests compared to those that declined remediation. Discussion: Through the academic remediation support process students appear to increase their mastery of "learning to learn" and are able to implement sustainable effective learning strategies to carry with them throughout their program. Conclusion: Students who accept academic remediation maintain a more successful academic profile compared to those that do not take advantage of this.

Impact of Progress testing on the learning experiences of students in medicine, dentistry and dental therapy.

AIMS: To investigate the impact of progress testing on the learning experiences of undergraduate students in three programs namely, medicine, dentistry and dental therapy. METHODS: Participants were invited to respond to an online questionnaire to share their perceptions and experiences of progress testing. Responses were recorded anonymously, but data on their program, year of study, age, gender, and ethnicity were also captured on a voluntary basis. RESULTS: A total of 167 participants completed the questionnaire yielding a response rate of 27.2% (n = 167). These included 96 BMBS students (27.4%), 56 BDS students (24.7%), and 15 BScDTH students (39.5%). A 3 -Program (BMBS, BDS, BScDTH) by 8-Topic (A-H) mixed analysis of variance (ANOVA) was conducted on the questionnaire responses. This revealed statistically significant main effects of Program and Topic, as well as a statistically significant interaction between the two (i.e. the pattern of topic differences was different across programs). CONCLUSIONS: Undergraduate students in medicine, dentistry, and dental therapy and hygiene regarded PT as a useful assessment to support their learning needs. However, in comparison to students in dentistry and dental therapy and hygiene, the perceptions of medical students were less positive in several aspects of PT.

A new three-component formulation for the efficient whitening of teeth (Carbamide Plus).

OBJECTIVES: This study aimed to develop and characterise a new three-component dental whitening formulation which is as effective as the currently used carbamide peroxide but at significantly lower hydrogen peroxide concentrations. MATERIALS AND METHODS: The new formulation (Carbamide Plus) was prepared containing hydrogen peroxide, urea, and sodium tripolyphosphate and compared directly with carbamide peroxide (containing just hydrogen peroxide and urea). To evaluate the clinical effectiveness of 5% Carbamide Plus, a randomised double-blind placebo-controlled clinical trial was conducted comparing the tooth colour of 33 patients using L*a*b* scores at baseline and after a 2-week whitening treatment. The behaviour of the three components in solution was determined by (1)H and (31)P NMR spectroscopy and pH dilution experiments. RESULTS: This clinical trial revealed that 5% whitening gels containing Carbamide Plus were as effective as those containing 10% carbamide peroxide. (1)H and (31)P NMR spectroscopy revealed strong intermolecular interactions between hydrogen peroxide and both urea and sodium tripolyphosphate (STPP) with little apparent interaction between urea and STPP. CONCLUSIONS: In this manuscript, we postulate that this increased whitening efficiency is due to a marked increase in local pH upon dilution which destabilises the hydrogen peroxide and expedites the whitening process. We postulate Carbamide Plus to be a three-component adduct with two molecules of carbamide peroxide binding to a central STPP unit with no direct interaction between STPP and urea. There were no statistically significant differences between Carbamide Plus and 10% carbamide peroxide in tooth-whitening achieved at 2 weeks. These results were recorded following 2 weeks of 2-h daily wear of at-home trays. CLINICAL RELEVANCE: Carbamide Plus offers the potential of using significantly lower levels of hydrogen peroxide concentration to achieve similar dental whitening effects.

Hydroxyapatite, fluor-hydroxyapatite and fluorapatite produced via the sol-gel method: dissolution behaviour and biological properties after crystallisation.

Hydroxyapatite (HA), fluor-hydroxyapatite (FHA) with varying levels of fluoride ion substitution and fluorapatite (FA) were synthesised by the sol-gel method as possible implant coating or bone-grafting materials. Calcium nitrate and triethyl phosphite were used as precursors under an ethanol-water based solution. Different amounts of ammonium fluoride were incorporated for the preparation of the FHA and FA sol-gels. After heating and powdering the sol-gels, dissolution behaviour was assessed using ion chromatography to measure Ca(2+) and PO4 (3-) ion release. Biological behaviour was assessed using cellular proliferation with human osteosarcoma cells and alamarBlue™ assay. Statistical analysis was performed with a two way analysis of variance and post hoc testing with a Bonferroni correction. Increasing fluoride substitution into an apatite structure decreased the dissolution rate. Increasing the firing temperature of the HA, FHA and FA sol-gels up to 1,000 °C decreased the dissolution rate. There was significantly higher cellular proliferation on highly substituted FHA and FA than on HA or Titanium. The properties of an implant coating or bone grafting material can be tailored to meet specific requirements by altering the amount of fluoride that is incorporated into the original apatite structure. The dissolution behaviour can further be altered by the temperature at which the sol-gel is fired.

SARS-CoV-2 infection causes periodontal fibrotic pathogenesis through deregulating mitochondrial beta-oxidation.

The global high prevalence of COVID-19 is a major challenge for health professionals and patients. SARS-CoV-2 virus has four structural protein components: the spike protein, envelope protein, membrane protein, and nucleocapsid protein. The SARS-CoV-2 virus mutates predominantly in the spike proteins, whilst the other key viral components usually remain stable. Essentially the pathological functions of the SARS-CoV-2 virus on different cell types are still largely unknown. Previous studies have shown that the human oral cavity can potentially act as reservoir of the SARS-CoV-2 virus. However, the consequence of SARS-CoV-2 viral infection on human oral health has not been systematically examined. COVID-19 can cause severe oral mucosa lesions and is likely to be connected with poor periodontal conditions. Fibroblasts are the major cell type inside periodontal ligament (PDL) and express the SARS-CoV-2 receptor: Angiotensin-converting enzyme 2 (ACE2), whose expression level can increase upon bacterial infection hence potentially provide a direct route of SARS-CoV-2 infection to PDL fibroblasts. In this research, we aimed to study the pathogenicity of SARS-CoV-2 viral components on human fibroblasts. We found that by exposing to SARS-CoV-2, especially to the viral envelope and membrane proteins, the human periodontal fibroblasts could develop fibrotic pathogenic phenotypes, including hyperproliferation that was simultaneously induced with increased apoptosis and senescence. The fibrotic degeneration was mediated by a down-regulation of mitochondrial ß-oxidation in the fibroblasts. Fatty acid ß-oxidation inhibitor, etomoxir treatment could mirror the same pathological consequence on the cells, similar to SARS-CoV-2 infection. Our results therefore provide novel mechanistic insights into how SARS-CoV-2 infection can affect human periodontal health at the cell and molecular level with potential new therapeutic targets for COVID-19 induced fibrosis.

Smile esthetics: the influence of posterior maxillary gingival margin position.

PURPOSE: Successful replacement of posterior teeth using contemporary prosthodontic techniques in esthetically demanding cases relies upon visual replication of the natural posterior dentition and surrounding gingival architecture. There is currently little in the way of guidance for creating ideal or acceptable gingival relationships for posterior teeth. MATERIALS AND METHODS: A cross-sectional study was conducted comparing perceptions of four groups of individuals to six digitally manipulated images with various posterior teeth gingival margin position configurations. A total of 120 volunteers aged 12 years to 80 years, comprising 30 patients diagnosed with hypodontia, 30 patients diagnosed with periodontal disease, 30 patients without either condition, and 30 qualified dentists were recruited from the Eastman Dental Institute & Hospital, London. A ranked order of preference for each set was obtained, and this was repeated after a minimum time interval of 10 minutes. RESULTS: Posterior gingival margin configurations from 0 mm to 2 mm (measured at the first premolar) were deemed most esthetic by the majority of the patient groups; dentists had a strong preference for the 1 mm configuration. Dentists appeared to be more perceptive to the alterations in gingival positions. CONCLUSIONS: Posterior gingival margin configurations where the first premolar margins were 1 mm lower than the canine margins were deemed the most esthetically pleasing; however, it is likely that a range of acceptability of 1 mm deviations from this ideal exists.

Deletion of RBP-Jkappa gene in mesenchymal cells causes rickets like symptoms in the mouse.

Crosstalk between different signalling pathways provide deep insights for how molecules play synergistic roles in developmental and pathological conditions. RBP-Jkappa is the key effector of the canonical Notch pathway. Previously we have identified that Wnt5a, a conventional non-canonical Wnt pathway member, was under the direct transcriptional control of RBP-Jkappa in dermal papilla cells. In this study we further extended this regulation axis to the other two kind of skeletal cells: chondrocytes and osteoblasts. Mice with conditional mesenchymal deletion of RBP-Jkappa developed Rickets like symptoms. Molecular analysis suggested local defects of Wnt5a expression in chondrocytes and osteoblasts at both mRNA and protein levels, which impeded chondrocyte and osteoblast differentiation. The defects existing in the RBP-Jkappa deficient mutants could be rescued by recombinant Wnt5a treatment at both cellular level and tissue/organ level. Our results therefore provide a model of studying the connection of Notch and Wnt5a pathways with Rickets. Supplementary Information: The online version contains supplementary material available at 10.1007/s44194-022-00007-w.

Dental education in primary care: 14 years of Peninsula Dental School.

Peninsula Dental School, established in 2006, was the UK's first new dental school in 40 years. It had the freedom to develop a completely new dental education curriculum planned on pedagogic thinking, designed to equip the dental care professionals of the twenty-first century. This was based on three distinct pillars: professionalism (developing a student's trust in their own autonomy); dental skills of the highest order (not just technical skills but also communication skills); and social engagement. As such, a truly innovative approach to dental education was created that has strong roots in evidence.This paper describes the University of Plymouth Peninsula Dental School's achievements against these initial objectives under the following areas: training in primary care; a novel spiralling integrated curriculum and assessments; facilities reaching out to deliver patient care; bringing meaningful patient contact to students from the earliest months of their course; embedding community engagement within the curriculum; development of Peninsula Dental Social Enterprise; and team working, training a variety of dental care profession students side by side.The University of Plymouth Peninsula Dental School, working with all its partners, has successfully pioneered and delivered significant changes in the field of education and continues to strive to further develop these and more for the future.

'It is difficult to think about becoming what you have never seen': Black students' reflections around a career in academic dentistry.

This opinion piece considers the national representation of the Black population in the United Kingdom in an academic career in dentistry and draws on engagement with Black dental students to see what their perceptions of this are. Black people are under-represented in dentistry as a whole and the number of Black academics who teach dentistry to an increasing number of aspiring young Black dental students is exceedingly low. Black dental students do not see themselves represented by their teachers and therefore 'it is difficult to think about [them] becoming what [they] have never seen'. Black dental students themselves have started initiatives to establish a strong support network of aspiring and qualified Black dentists. Dialogue with them showcases that while there are pathways into an academic career in dentistry, these appear unclear to them. This piece is intended to raise awareness of these issues, in the knowledge that with mentoring, role modelling and dialogue, pathways may become clearer, opportunities may arise that were previously not considered and the national picture may one day change.

The dental therapist's role in a 'shared care' approach to optimise clinical outcomes.

Introduction Dental therapists have a key role to play in the provision of dentistry in the UK. The Dental Workforce Advisory Group has reported this is relevant in multiple areas, including prevention and care in young children, and to support dentists in providing advanced and routine treatment for complex adult patients within the wider collaborative dental team. There remain diverse and multiple barriers and challenges to utilising the optimal scope of the dental therapist in general practice. In 2013, the General Dental Council introduced direct access (DA) legislation in the UK. By utilising the potential of dental therapists, some of the above challenges could be overcome and the DA approach optimised.Aims The purpose of this article through presenting clinical cases is to demonstrate the full scope of practice of the dental therapist and highlight how clinical outcomes can be optimised for patients when a 'shared care' approach is followed.Conclusions Notwithstanding the complexities of the financial implications practice owners face, through knowledge and understanding of the role and scope of the dental therapist within the wider dental team, optimal treatment of dental patients in the UK can be encouraged.

Addressing racial inequalities in dental education: decolonising the dental curricula.

The aim of this paper is to highlight the impact of racial disparities on the educational experiences of Black and minority ethnic students in healthcare education. Attainment gaps and barriers to career progression for minority ethnic home students in the United Kingdom have been recognised for decades, but little progress has been made to address these issues. Students and staff in higher education have been campaigning for 'decolonisation of the curriculum' to improve inclusivity and representation. These trends are being mirrored in medical education and there is growing recognition to decolonise the medical curricula. This would improve the educational experience and attainment of minority ethnic students and doctors, and would also help to address disparities in healthcare provision for minority ethnic patients. The context for decolonisation of the dental curricula is provided, followed by a discussion on the benefits, challenges and strategies for such decolonisation.

Orthodontics using an occlusal splint: a clinical report.

Careful management of the occlusion is necessary for successful prosthodontic treatment. A reorganized occlusal approach requires a more accurate registration of the desired jaw position, and where it is difficult to achieve this, an occlusal splint is indicated. This clinical report documents a 60-year-old man with a Prosthodontic Diagnostic Index Class IV dentition, who prior to a full-mouth reconstruction, underwent occlusal splint therapy with a Michigan-type splint that incorporated z-springs to allow concurrent orthodontic tooth movement of two anterior teeth to positions that would allow favorable restorations by correcting occlusal and esthetic form.

Multimorbidity and oral health: need for new models of care.

Multimorbidity is defined as patients living with two or more chronic health conditions. The prevalence of multimorbidity is increasing, driven by the ageing population, and represents a major challenge to all healthcare systems because these patients are heavy users of services. The link with oral health is growing although there is need for further robust evidence. There is also need for new models of care to address oral health in patients with multimorbidity.

The biocompatibility of silver and nanohydroxyapatite coatings on titanium dental implants with human primary osteoblast cells.

Silver nanoparticles (Ag NPs) are antimicrobial, with potential uses in medical implants, but Ag NPs alone can also be toxic to mammalian cells. This study aimed to enhance the biocompatibility of Ag NP-coated titanium dental implants with hydroxyapatite (HA) applied to the surface. Ti6Al4V discs were coated with Ag NPs, Ag NPs plus HA nanoparticles (Ag + nHA), or Ag NPs plus HA microparticles (Ag + mHA). The stability of coatings was explored and the biocompatibility with primary human osteoblasts over 7 days. Results showed that Ti6Al4V discs were successfully coated with silver and HA. The primary particle size of nHA and mHA were 23.90 ±â€¯1.49 nm and 4.72 ±â€¯0.38 µm respectively. Metal analysis showed that underlying silver coatings remain stable in DMEM culture media, but the presence of FBS in the media caused some initial (clinically beneficial) release of dissolved silver. With additions of HA, osteoblasts were adherent, had normal morphology, negligible lactate dehydrogenase (LDH) leak, and showed alkaline phosphatase (ALP) activity. Cell viability was around 70% throughout the Ag + nHA treatment. Overall, the implants coated with Ag + nHA maintained a higher degree of biocompatibility compared to those coated with Ag + mHA, or Ag NPs alone, suggesting the former has a benefit for clinical use.

Antibacterial properties of silver nanoparticles grown in situ and anchored to titanium dioxide nanotubes on titanium implant against Staphylococcus aureus.

Medical grade titanium alloy, Ti-6Al-4V, with TiO2 nanotubes (TiO2-NTs) grown on the surface and then decorated with silver nanoparticles (Ag NPs) is proposed to enhance the antimicrobial properties of the bone/dental implants. However, the decoration with Ag NPs is not consistent and there are concerns about the direct contact of Ag NPs with human tissue. The aim of this study was to achieve a more even coverage of Ag NPs on TiO2-NTs and determine their biocidal properties against Staphylococcus aureus, with and without a top coat of nano hydroxyapatite (nHA). The decoration with Ag NPs was optimised by adjusting the incubation time of the TiO2-NTs in a silver ammonia solution, and using biocompatible δ-gluconolactone as a reducing agent. The optimum incubation in silver ammonia was 7 min, and resulted in evenly distributed Ag NPs with an average diameter of 47.5 ± 1.7 nm attached to the surface of the nanotubes. The addition of nHA did not compromise the antimicrobial properties of the materials; high-resolution electron microscopy showed S. aureus did not grow on the composite with nHA and with >80% biocidal activity measured by the LIVE/DEAD assay, also limited lactate production. Dialysis experiment confirmed the stability of the coatings, and showed a slow release of dissolved silver (3.27 ± 0.15 µg/L over 24 h) through the top coat of nHA.

The effect of engaging the screw access channel of an implant abutment with a cement-retained restoration.

PURPOSE: Factors affecting the retention of fixed prostheses to natural abutments are well understood. In contrast, little is known concerning the factors influencing the retention of fixed prostheses cemented to implant abutments. The purpose of this study was to investigate the effect that extending a casting into the screw access channel of an implant abutment has on the retention when cemented using Temp Bond. MATERIALS AND METHODS: Replace Select Straight abutments received set modifications (buccal wall removal at 15 degrees , 22 degrees , and 30 degrees ) using a milling machine; controls were unmodified. Two castings were fabricated for each of the modified abutments, one with and one without an extension into the screw access channel. Following cementation with Temp Bond under standardized conditions, the castings were removed from the abutments using an Instron machine, and the peak removal force was recorded. RESULTS: Extending the casting into the screw access channel significantly (p < 0.001) increased the peak load of removal. Significant differences (p < 0.05) were found between no modification and 30 degrees modification, 15 degrees and 30 degrees modification, and 22 degrees and 30 degrees modification in the groups when the casting extended into the abutment. In the group where the casting did not extend into the abutment, all groups were significantly different (p < 0.001) with the exception of 22 degrees and 30 degrees modification. CONCLUSIONS: The increased load required to remove a casting that extends into the screw access channel of an implant abutment may compensate for loss in retention, which occurs through unfavorable modification of the abutment.

An analysis of the effect of a vent hole on excess cement expressed at the crown-abutment margin for cement-retained implant crowns.

PURPOSE: The labial margins of anterior implant-retained crowns are often positioned subgingivally for a superior esthetic appearance. One of the consequences of subgingival margins is the increased risk of leaving excess cement behind following cementation. This can lead to potential problems, including peri-implant inflammation, soft tissue swelling, soreness, bleeding or suppuration on probing, and bone loss. The purpose of this laboratory study was to investigate the effect of placement, location, and diameter of a vent hole on the amount of cement being expressed at the margin of an anterior implant abutment-retained crown. MATERIALS AND METHODS: Three implant crown copings were fabricated to fit on the same custom abutment. Three vent diameters (0.75, 1.25, and 1.65 mm) and three locations on the palatal surface of the coping (cervico-palatally, mid-palatally, inciso-palatally) were chosen for vent hole placement. For each test, the coping was cemented onto the abutment under standardized conditions. A preweighed thin coating of cement was applied to the fit surface of the coping. The amount of cement expressed at the margin and vent hole was measured by weight and calculated as a proportion of the amount of cement placed in the coping before seating. The procedure was completed 15 times for each variable. The results were statistically analyzed using univariate ANOVA with post hoc Bonferroni-adjusted independent samples t-tests. RESULTS: The presence of a vent hole influenced the proportion of cement expressed at the coping margin (p < 0.05). The location of a vent hole influenced the proportion of cement expressed at the coping margin (p < 0.05), with the exception of the mid-palatal and inciso-palatal positioning where there was no significant difference (p= 0.61) between groups. The diameter of the vent hole did not significantly influence the proportion of cement expressed at the coping margin (p= 0.096). CONCLUSIONS: When using anterior cement-retained implant crowns, the use of a 0.75-mm mid-palatal or inciso-palatal vent hole to minimize the amount of cement expressed at the margin during cementation should be considered.