Socioenvironmental sugar promotion and geographical inequalities in dental health of 5-year-old children in England

OBJECTIVES

To investigate the relationship between socioenvironmental sugar promotion and geographical inequalities in the prevalence of dental caries amongst 5-year-olds living across small areas within England.

METHODS

Ecological data from the National Dental Epidemiology Programme (NDEP) 2018-2019, comprising information on the percentage of 5-year-olds with tooth decay (≥1 teeth that are decayed into dentine, missing due to decay, or filled), and untreated tooth decay (≥1 decayed but untreated teeth), in lower-tier local authorities (LAs) of England. These were analysed for association with a newly developed Index of Sugar-Promoting Environments Affecting Child Dental Health (ISPE-ACDH). The index quantifies sugar-promoting determinants within a child's environment and provides standardized scores for the index, and its component domains that is, neighbourhood-, school- and family-environment, with the highest scores representing the highest levels of sugar promotion in lower-tier LAs (N = 317) of England. Linear regressions, including unadjusted models separately using index and each domain, and models adjusted for domains were built for each dental outcome.

RESULTS

Participants lived across 272 of 317 lower-tier LAs measured within the index. The average percentage of children with tooth decay and untreated tooth decay was 22.5 (SD: 8.5) and 19.6 (SD: 8.3), respectively. The mean index score was (0.1 [SD: 1.01]). Mean domain scores were: neighbourhood (0.02 [SD: 1.03]), school (0.1 [SD: 1.0]), and family (0.1 [SD: 0.9]). Unadjusted linear regressions indicated that the LA-level percentage of children with tooth decay increased by 5.04, 3.71, 4.78 and 5.24 with increased scores of the index, and neighbourhood, school and family domains, respectively. An additional model, adjusted for domains, showed that this increased percentage predicted by neighbourhood domain attenuated to 1.37, and by family domain it increased to 6.33. Furthermore, unadjusted models indicated that the LA-level percentage of children with untreated tooth decay increased by 4.72, 3.42, 4.45 and 4.97 with increased scores of the index, and neighbourhood, school, and family domains, respectively. The model, adjusted for domains, showed that this increased percentage predicted by neighbourhood domain attenuated to 1.24 and by family domain rose to 6.47. School-domain was not significantly associated with either outcome in adjusted models.

CONCLUSIONS

This study reveals that socioenvironmental sugar promotion, particularly within neighbourhood- and family-environments, may contribute to geographical inequalities in dental caries in children. Further research involving data on individual-level dental outcomes and confounders is required.

Oral manifestations of long COVID and the views of healthcare professionals

Introduction Oral manifestations have been observed with this condition; however, little is known about their impact on the healthcare professionals routinely managing these patients.Aims To investigate the prevalence of the oral manifestations of long COVID and the healthcare professionals' views, experiences and practices for managing these conditions.Materials and methods A cross-sectional mixed-methods study, including a self-reported online questionnaire (n = 104) and healthcare professionals' (n = 7) semi-structured interviews, was conducted. Descriptive statistics and reflexive thematic analysis were used to analyse the data.Results In total, 78% of respondents reported one or more oral conditions associated with COVID-19. Changes in the sense of taste and/or smell (58%), dry mouth (48.1%) and mouth sores (45.7%) were frequently reported. Themes identified from healthcare professionals' interviews were areas for research, management and interdisciplinary collaboration.Discussion Allied healthcare professionals may assist dental professionals with managing oral manifestations of long COVID. Inadequate access to NHS dentistry is deterring patients worried about their oral symptoms and the limited oral knowledge of healthcare professionals affects their ability to manage patients.Conclusion Healthcare professionals have observed oral manifestations in individuals diagnosed with long COVID; however, further information and training on this topic would assist them with managing patients and increasing awareness among clinicians.

Translucency of Lithium-Based Silicate Glass-Ceramics Blocks for CAD/CAM Procedures: A Narrative Review

Amid chairside CAD/CAM materials, the use of lithium-based silicate glass-ceramics (LSGC) has been steadily increasing. This review aims to report on the translucency of these materials and the variables used to measure it. An electronic search was performed within the PubMed database within the period between 2 June 2011 and 11 September 2022. English-language papers investigating the translucency of IPS e.max CAD, Celtra Duo, Suprinity PC, Initial LiSi Block, Amber Mill, N!ce, and CEREC Tessera LSGC CAD/blocks were included in the search strategy. After an initial retrieval of 160 papers, the application of exclusion criteria, and the screening of abstracts and then of full texts, 33 papers were included in the study. The retrieved materials, with different degrees of translucency (LT, HT), were IPS e.max CAD (n = 33), Suprinity PC (n = 8), and Celtra Duo (n = 1). Concerning the examined colors, the most used was A2 (n = 20), followed by A1 (n = 8) and A3 (n = 2). The translucency parameter (TP) was the most used method (n = 30) with respect to the contrast ratio (CR) (n = 11) to assess translucency. Five papers measured both. Several specimens' thicknesses (0.5-4 mm) were investigated, with 1 mm (n = 23) being the most frequently analyzed. While a general tendency could be identified, conflicting results among different papers were reported.

Dental Teacher Feedback and Student Learning: A Qualitative Study

INTRODUCTION

Feedback is essential to improve student learning and motivation and to encourage curriculum development by teachers. This study looked at feedback to and from dental students from a qualitative perspective.

METHODS

Dental teachers were recruited exclusively to this study from the membership of the Association for Dental Education in Europe (ADEE). Delegates from each of the four annual ADEE conferences were invited to attend focus groups to discuss aspects of feedback. Focus groups established an individual theme for the respective conferences: (i) the role of the teacher in delivering feedback; (ii) feedback from the students' perspective; (iii) changes to feedback due to the COVID-19 pandemic; and (iv) integrating feedback with assessments.

RESULTS

Qualitative data collected from the conference delegates were diverse and thought provoking. Delegates reported different styles of feedback varying from individual, personal feedback to no feedback at all. An enforced and mostly positive adaptation to online delivery during the COVID-19 pandemic was reported. A partial return to pre-pandemic practices was described.

CONCLUSIONS

Feedback is well recognized by students and teachers as contributing to learning. A universal approach to delivering feedback as part of the student learning process can be challenging due to a multitude of variables. Many aspects of changes in dental education, teaching, and feedback practices adopted as a result of the COVID-19 pandemic have been retained post-pandemic, thereby accelerating the anticipated progression to online teaching.

Flexural Strength of CAD/CAM Lithium-Based Silicate Glass-Ceramics: A Narrative Review

Amongst chairside CAD/CAM materials, the use of lithium-based silicate glass-ceramics (LSGC) for indirect restorations has recently been increasing. Flexural strength is one of the most important parameters to consider in the clinical selection of materials. The aim of this paper is to review the flexural strength of LSGC and the methods used to measure it.

METHODS

The electronic search was completed within PubMed database from 2 June 2011 to 2 June 2022. English-language papers investigating the flexural strength of IPS e.max CAD, Celtra Duo, Suprinity PC, and n!ce CAD/CAM blocks were included in the search strategy.

RESULTS

From 211 potential articles, a total of 26 were identified for a comprehensive analysis. Categorization per material was carried out as follows: IPS e.max CAD (n = 27), Suprinity PC (n = 8), Celtra Duo (n = 6), and n!ce (n = 1). The three-point bending test (3-PBT) was used in 18 articles, followed by biaxial flexural test (BFT) in 10 articles, with one of these using the four-point bending test (4-PBT) as well. The most common specimen dimension was 14 × 4 × 1.2 mm (plates) for the 3-PBT and 12 × 1.2 mm (discs) for BFT. The flexural strength values for LSGC materials varied widely between the studies.

SIGNIFICANCE

As new LSGC materials are launched on the market, clinicians need to be aware of their flexural strength differences, which could influence the clinical performance of restorations.

Students' perceptions of tutor feedback: a pilot study

BACKGROUND

Feedback offered to dental students by their tutors should aim to elicit ongoing learning and motivation. Previous studies looked at the impact on learning of feedback delivered by tutors from tutors' perspectives. However, what students know about feedback and its purposes and how they experience them during their study effect the impact of feedback on learning. The aim of this pilot study was to assess the proprieties of tutor feedback and its impact on future learning from the students' perspective.

METHODS

A short questionnaire based cross sectional survey was designed and delivered electronically to 135 undergraduate and postgraduate students at Brescia Dental School, Italy. The questionnaire consisted of 16 questions which were divided into 3 sections. Quantitative data were collected via Google Forms, the analysis of the data was undertaken using SPSS software, Version 24.

RESULTS

Sixty-one students (45.2%) responded to the questionnaire. Forty-one of respondents (67.2%) were undergraduate students and 20 (32.8%) were postgraduate students. The vast majority of students indicated that they received feedback, thirty (49.2%) indicated that it was delivered by tutors and eight (13.1%) by fellow students. Further, students reported that feedback was timely, delivered within two weeks of assessments and that constructive criticism was the favoured feedback style (N.=52, 85.2%). Most students felt that the feedback they received helped with ongoing learning (N.=54, 88.5%).

CONCLUSIONS

Most of the respondents considered that feedback received at Brescia Dental school did have a positive impact on their learning. This is of course what tutors hope would be the case but nevertheless it is gratifying to receive this endorsement from the respondent students. A more comprehensive study involving multiple dental schools in different learning environments will now be undertaken, including the collection of qualitative data.

Influence of Thickness of Opaque Porcelain and Alloy Color on the Final Color of Porcelain-Fused-to-Metal Restorations

Despite the advent of metal-free solutions, porcelain-fused-to-metal restorations (PFM) are still widely used. Particularly for the latest ceramic systems, scarce information is present in the scientific literature about the ideal opaque layer thickness and the alloy color impact to achieve the desired final color of PFM restorations. This study aimed to evaluate the influence of opaque thickness variation layered on different metal alloys on the final color of PFM restorations. Opaque porcelain of one metal−ceramic system (VITA VM13) was layered in four different thicknesses (0.10 mm, 0.15 mm, 0.20 mm, and 0.25 mm) on three differently colored dental alloys: a gold−platinum alloy (yellowish), a gold−palladium alloy (light grayish), and a nickel−chromium alloy (dark grayish). The veneering porcelain layered over the opaque was kept constant (Base Dentine 0.45 mm, Transpa Dentine 0.50 mm, and Enamel 0.20 mm). Sixty specimens were fabricated, five samples for each combination of alloy/opaque thickness. The color difference (ΔE) between specimen and reference was measured using a clinical spectrophotometer. The two-way ANOVA revealed that the thickness of both the opaque (p < 0.001) and the metal alloy (p < 0.001) significantly influenced the ΔE values. Gray-colored alloys covered by a 0.10 mm thick opaque layer enabled the closest color match, whereas this occurred for yellow-color alloys covered by a 0.15 mm thick opaque layer. In contrast, the samples covered by a 0.25 mm thick opaque layer obtained the worst ΔE.

Factory Crystallized Silicates for Monolithic Metal-Free Restorations: A Flexural Strength and Translucency Comparison Test

Flexural strength (FS) and translucency (Contrast Ratio-CR) of three different factory crystallized silica-based glass ceramics, Celtra Duo (CD), N!ce (NI) and Li-Si Block, a lithium disilicate, IPS e.max CAD (LD), and a leucite-reinforced feldspathic ceramic, Empress CAD (EM), in two different translucencies (HT and LT) for use in chairside dental restorations have been compared. CAD blocks of the materials were cut into beams and tiles and processed following manufacturers’ instructions. The beams were tested (3-PBT) to determine flexural strength, Weibull characteristic strength, and Weibull modulus; and tiles were tested to determine CR. All data were statistically analyzed. In addition, SEM analysis of the materials was performed. Differences in flexural strength (FS) and translucency (CR) between the materials were found to be statistically significant. FS decreased as follows (MPa): LDHT 350.88 ± 19.77 (a) = LDLT 343.57 ± 18.48 (a) > LSLT 202.15 ± 17.41 (b) = LSHT 196.93 ± 8.87 > NIHT 186.69 ± 13.06 (c) = CDLT 184.73 ± 13.63 (c) = CDHT 174.15 ± 21.76 (c) = NILT 172.12 ± 11.98 (c) > EMHT 131.16 ± 13.33 (e) = EMLT 127.65 ± 11.09. CR decreased as follows (mean ± sd): CDLT 74.1 ± 1.1 (a); LSLT 74.0 ± 1.1 (ab); NILT 73.3 ± 0.8 (ab); EMLT 73.0 ± 1.5 (ab); NIHT 72.4 ± 1.0 (bc); LDLT 71.3 ± 1.1 (bc); LTHT 65.2 ± 0.9 (de); LSHT 63.8 ± 1.1 (def); EMHT 636 ± 1.2 (ef); CDHT 62.2 ± 0.8 (f). Our findings show that factory-crystallized lithium silicate glass ceramics fulfill ISO standards for Classes 1 and 2. Therefore, they can be considered viable alternatives to produce single-unit restorations with a chairside procedure not requiring thermal treatment.

Detection of dental fomites using topical fluorescein

Background Thorough disinfection of dental facilities is of paramount importance during the COVID-19 pandemic. Patients, clinicians, students and nurses can all be infected by aerosols and dental droplets bearing COVID-19. However, droplets are transparent and often microscopic, so are difficult to detect in clinical practice.Methods To better understand the spread of dental droplets, we stained the dental irrigant with fluorescein and performed a series of procedures on a dental manikin. We then viewed droplets and fomite spread around the dental chair, with and without an ultraviolet (UV) light.Results Observations without the UV light showed minimal or no fluid spread. However, using UV light, we detected fluorescein on the dentist, chairs and the handpiece, as well as splatter on the floor and on the instrument tray. This was of educational value to the staff, who were reminded how far droplets had spread.Conclusion Fluorescein facilitates the detection of droplet spread and helps clinical staff to see high-risk areas that require in-depth cleaning. As clinical grade fluorescein is cheap and widely available, this technique may be useful for dental practices to train staff in the thorough decontamination of the clinical environment.

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.

Exploring narrative feedback to undergraduate dental hygiene and dental therapy students

PURPOSE/OBJECTIVES

The nature and quality of feedback provided during the training of healthcare students have been found to influence the progress of students throughout their clinical practice. The use of electronic systems for feedback is becoming more prevalent; but there appears to be an absence of research into the use of these systems with Dental Hygiene and Dental Therapy students (DHDT). The aim of this study was to explore the written, narrative feedback provided by tutors to undergraduate DHDT students on a 3-year BSc programme, using Liftupp - an Information Management System that incorporates electronic feedback mechanisms.

METHODS

The data comprised written, narrative feedback to DHDT students (n = 96) on clinical performance in academic Years Two and Three entered into Liftupp by five clinical tutors (n = 5) over 2 academic years. These feedback comments were subjected to a thematic analysis and matrix queries using NVivo.

RESULTS

Ten major themes were identified. Preliminary findings indicated that the constructive "Descriptive" theme was prominent across all tutors, while other constructive themes: "Directive" and "Positive" were linked more to individual tutors. The less constructive themes were infrequent in tutor feedback. In addition, unique feedback profiles for tutors were generated.

CONCLUSIONS

The analysis of narrative feedback from tutors on Liftupp enables the identification of feedback trends that can be reviewed and shared with tutors to improve the quality of their feedback. In addition, this research can be used to inform tutor training to promote the use of meaningful and effective feedback. Potential further research and limitations have been identified.

Teacher feedback and student learning: A quantitative study

INTRODUCTION

Feedback plays a significant role in informing students about the outcome of their assessments and contributes to their ongoing learning. The aim of this study was to investigate feedback currently given by clinical teachers to dental students throughout Europe.

METHODS

This study used a piloted questionnaire, delivered on-line to members of the Association for Dental Education in Europe (ADEE). A largely quantitative approach was adopted with multiple-choice, single answer, open text boxes and Likert scale type questions. These data were collected via Google Forms, transferred to an excel spreadsheet and analysed using SPSS software Version 24.

RESULTS

Data were collected from 223 questionnaires completed by respondents from 42 countries. Students received feedback following: (i) formative assessment (70%; n = 155), (ii) summative assessment (88%; n = 196) and iii) informally at any time (85%; n = 188). Feedback was delivered by different people including administrative staff (15%; n = 25). Several methods were used to deliver feedback, including written, oral/spoken, email and individually or as a group. 85% (n = 184) of teachers reported that their teaching had changed following feedback they had received from students.

CONCLUSION

The study showed a strong ethos of delivering feedback from teachers to dental students following both assessment and non-assessment related activities. Teachers should understand/appreciate the individualistic nature of feedback and the importance of cultivating a congenial environment for feedback delivery. Challenges remain in delivering them to a high standard and in a timely manner.

e-Oral health interventions for older patients in an outreach primary dental care centre: A pilot trial nested acceptability study

OBJECTIVE

To compare the acceptability and perceived helpfulness of an e-Oral Health intervention in form of text messages versus standard dental leaflets provided after a dental visit to patients aged 65 years and over.

BACKGROUND

Oral health care needs for older people are increasing. Remote interventions using e-Health can ensure oral care is provided despite physical hindrances or situations where dental appointments are limited such as has happened more widely during the COVID-19 pandemic.

MATERIALS AND METHODS

Mixed-method nested study within a pilot trial. Dental patients (n = 150) at an outreach primary dental care centre, ≥ 65 years old, were recruited and randomly allocated to e-Oral health text messages or leaflet intervention arms. Post-intervention (6 months), participants responded to open and closed-ended two-way survey phone texts. Survey questions investigated: (a) whether they would recommend the intervention, (b) intervention helpfulness and (c) OPEN feedback. Average helpfulness scores (Scale:1= Very Helpful to 5= Not Helpful at All) were compared for each arm using Independent Sample t-test. Percentage of participants providing positive recommendations in each arm were compared using chi-squared tests. Qualitative findings were analysed using thematic analysis.

RESULTS

N = 68 (45%) responded. Mean helpfulness scores in text group M = 2.2, SD=1.1) and leaflet group M = 2.3, SD=1.9, P = .29. Amongst the text arm respondents, 89% compared with 68.2% in leaflet arm; P = .005 would recommend the intervention. Four qualitative themes were outlined: intervention approach, content, behavioural impact and recommendations.

CONCLUSION

e-Oral Health text interventions are acceptable and helpful to older people, but these messages need to be tailored.

Flexural resistance of CAD-CAM blocks. Part 3: Polymer-based restorative materials for permanent restorations

PURPOSE

Concurrently with the growing interest in CAD-CAM systems, several new materials of different chemical nature have become available. As an alternative to ceramics, numerous polymer-based materials have recently been proposed for permanent prosthetic restorations. Aim of this study was to test the CAD-CAM polymer-based materials available on the market, comparing mean flexural strength, Weibull characteristic strength and Weibull modulus.

METHODS

Seven types of polymer-based blocks were tested: Lava Ultimate, 3M; Brilliant Crios, Coltene; Cerasmart, GC; Block HC, Shofu; Katana Avencia, Noritake; Grandio Blocs, Voco; Tetric CAD, and Ivoclar-Vivadent. Specimens were cut out from blocks, finished, polished, and tested in a three-point bending test apparatus until failure (n=30). Flexural strength, Weibull characteristic strength, and Weibull modulus were calculated. Flexural strength data were statistically analyzed. ANOVA on Ranks was applied, followed by the Dunn's test for post hoc comparisons (P= 0.05).

RESULTS

Flexural strength values (MPa) were measured (mean±standard deviation). Different letters in parentheses label statistically significant differences: Grandio Blocs 266±24(a), Brilliant Crios 259±21(ab); Tetric CAD 254±15(ab); Katana Avencia 241±29(bc); Cerasmart 221±24(cd); Lava Ultimate 196±23(de); Block HC 139±10(e). All the tested materials had flexural strengths greater than 100 MPa, thereby satisfying the requirements of ISO standards for polymer-based materials. For all the tested materials the Weibull characteristic strength was greater than 100 MPa. Weibull modulus ranged between 21.20 (Tetric CAD) and 9.09 (Katana Avencia).

CLINICAL SIGNIFICANCE

Even though all the CAD-CAM polymer-based materials marketed in blocks tested in the present study satisfy the requirements of ISO standard for polymer-based materials, their flexural resistance differs significantly. The data presented in the study may be helpful to clinicians for selecting the most appropriate materials for each clinical case.

Influence of Acid Concentration and Etching Time on Composite Cement Adhesion to Lithium-silicate Glass Ceramics

PURPOSE

To evaluate the influence of hydrofluoric acid (HF) concentration and etching time on the microshear bond strength (µSBS) of RelyX Unicem 2 (3M Oral Care) to VITA Suprinity (Vita Zahnfabrik; zirconia-reinforced lithium-silicate glass ceramic: ZLS) and IPS e.max CAD (Ivoclar Vivadent; lithium-disilicate glass ceramic: LD).

MATERIALS AND METHODS

Forty-eight bars each were fabricated of ZLS and LD with Cerec InLab MC-XL. For each material, 8 groups were formed with respect to etching time (20, 40, 60, 120 s) and HF concentration (4.9% and 9.5%). In each group, after etching and silanization, 15 cylindrical specimens of RelyX Unicem 2 were built up for µSBS testing with a special device. Data were analyzed using three-way ANOVA. Failure modes were assessed using an optical stereomicroscope, classified as adhesive, cohesive in resin or ceramic, or mixed. Failure modes were statistically analyzed using Fisher's Exact Test. One bar per group was prepared for SEM observation of the etched surface.

RESULTS

ZLS showed significantly higher bond strengths than LD (p < 0.001). Etchant concentration was an influential factor with superior strengths after 4.9% HF etching (p = 0.009). Etching time did not significantly affect adhesion (p = 0.066). The material-etching interaction was statistically significant (p = 0.004). Particularly for ZLS, 4.9% HF etching obtained significantly higher bond strengths than did 9.5%. By using 4.9% HF, adhesion was significantly higher on ZLS than on LD.

CONCLUSION

Material and HF concentration influenced the adhesion between RelyX Unicem 2 composite cement and lithium-silicate glass ceramics. Etching time was not an influential factor. The use of 4.9% HF for 20 s proved to be the most effective etching treatment of the intaglio surface.

Cement opacity and color as influencing factors on the final shade of metal-free ceramic restorations

OBJECTIVE

To investigate the influence of opacity and color of luting cements on the final shade of metal-free restorations.

MATERIALS AND METHODS

Five resin cement colors in combination with four different thicknesses of CAD/CAM ceramic materials were tested, and a composite substrate was used as dentin color reference (n = 3). Specimen color was measured with a spectrophotometer equipped with an integrating sphere before and after cementation (CIELAB). Cement and ceramic color and opacity (TP) were assessed by measuring the tested ceramic thickness as a 1-mm thick disk for each of the cement shades. The differences in color were evaluated (ΔE₀₀ ). Data were statistically analyzed by a Two-Way ANOVA followed by the Tukey Test for post-hoc comparison (P < .05) and multiple comparison Pearson's test (P < .05); the acceptability and perceptibility threshold were evaluated.

RESULTS

Statistically significant influence was found for factors ceramic thickness and cement shade (P < .001). Perceptible and unacceptable color changes were induced on the final restoration by resin cements (ranging from ΔE₀₀  = 0.69 ± 0.54 to ΔE₀₀  = 5.53 ± 0.46), the correlation between factors became strong (r²  > 0.6) in case of mismatch between color and translucency of cement and ceramic. Only the clear shade in combination with the thickest ceramic, resulted in an imperceptible color change (ΔE₀₀  = 0.69 ± 0.54).

CONCLUSIONS

The final shade of ceramic restorations can be influenced by resin cements; the magnitude of influence is related to the cement optical properties.

CLINICAL SIGNIFICANCE

In order to influence the final shade of a ceramic restoration, a cement more opaque than the restorative material should be used. Conversely, in the case of a fitting shade of the restoration, a cement more translucent than the restoration should be used to avoid undesired changes.

Bracket bonding to polymethylmethacrylate-based materials for computer-aided design/manufacture of temporary restorations: Influence of mechanical treatment and chemical treatment with universal adhesives

Objective

To assess shear bond strength and failure mode (Adhesive Remnant Index, ARI) of orthodontic brackets bonded to polymethylmethacrylate (PMMA) blocks for computer-aided design/manufacture (CAD/CAM) fabrication of temporary restorations, following substrate chemical or mechanical treatment.

Methods

Two types of PMMA blocks were tested: CAD-Temp® (VITA) and Telio® CAD (Ivoclar-Vivadent). The substrate was roughened with 320-grit sandpaper, simulating a fine-grit diamond bur. Two universal adhesives, Scotchbond Universal Adhesive (SU) and Assure Plus (AP), and a conventional adhesive, Transbond XT Primer (XTP; control), were used in combination with Transbond XT Paste to bond the brackets. Six experimental groups were formed: (1) CADTemp®/SU; (2) CAD-Temp®/AP; (3) CAD-Temp®/XTP; (4) Telio® CAD/SU; (5) Telio® CAD/AP; (6) Telio® CAD/XTP. Shear bond strength and ARI were assessed. On 1 extra block for each PMMA-based material surfaces were roughened with 180-grit sandpaper, simulating a normal/medium-grit (100 mm) diamond bur, and brackets were bonded. Shear bond strengths and ARI scores were compared with those of groups 3, 6.

Results

On CAD-Temp® significantly higher bracket bond strengths than on Telio® CAD were recorded. With XTP significantly lower levels of adhesion were reached than using SU or AP. Roughening with a coarser bur resulted in a significant increase in adhesion.

Conclusions

Bracket bonding to CAD/CAM PMMA can be promoted by grinding the substrate with a normal/medium-grit bur or by coating the intact surface with universal adhesives. With appropriate pretreatments, bracket adhesion to CAD/CAM PMMA temporary restorations can be enhanced to clinically satisfactory levels.

The impact of confidence on clinical dental practice

INTRODUCTION

Increasing confidence through learning has the potential to change General Dental Practitioners' (GDPs) perceptions of clinical practice. By examining how changes in confidence influence the clinical practice of two cohorts of GDPs, during and following an extended period of postgraduate training, we show the importance of confidence to GDPs and that a lack of confidence is a primary reason why GDPs attend postgraduate training courses.

METHODS

A mixed-method approach was adopted for this study. Quantitative data were collected via a series of linked questionnaires; qualitative data were collected using focus group discussions, interviews and contemporaneous field notes. Analysis was undertaken using SPSS software and a phenomenological approach, respectively.

FINDINGS

Participants indicated an increase in confidence in their ability to undertake dental procedures, which led to an increase in confidence in communication skills, and their ability to undertake complex restorative procedures. This led to greater treatment acceptance by patients resulting in better "job satisfaction."

DISCUSSION

A sense of confidence is central to personal development and ongoing study, leading to first, an improved capability to perform tasks (competence); second, confidence is a product of the relationship and trust of those people associated with the individual/professional and third, the correct level of challenge is important to confidence.

CONCLUSIONS

The issue of confidence has not been looked at in postgraduate dentistry, but it is well recognised in medical education fields.

Patient perceptions of healthy weight promotion in dental settings

INTRODUCTION

Excess weight is a risk factor for systemic and oral diseases. Since dental professionals are already involved in imparting overall health messages when certain conditions impact oral health, it should make sense that they also deliver related health messages such as promoting the maintenance of healthy weight for patients.

OBJECTIVES

This study evaluated the perceptions of adult patients attending private dental clinics on healthy weight promotion by dental professionals.

METHODS

A cross-sectional multicenter survey was designed and set in four private dental clinics (London/Hampshire) between April and July 2015. All eligible patients (≥ 18 years) completed a questionnaire. Body Mass Index (BMI; kg/m²) was calculated from height and weight measurements. Questionnaire content was centred on patient perceptions of 6 domains with the primary domain as to whether patients would accept healthy weight promotion by dental professionals.

RESULTS

213 adults (aged 20-85 years) participated in this study and 58.2% were females. Although the overwhelming majority endorsed healthy weight promotion by the dental team, the overweight/obese were significantly more sensitive (BMI screening χ2 trend = 6.840, p = 0.009; healthy weight information χ2 trend = 6.231, p = 0.013). Awareness of risk of periodontitis, carcinoma and overall adverse health outcomes associated with overweight or obesity was low.

CONCLUSION

The study cohort was well primed for healthy weight advice. Routine healthy weight promotion and BMI screening should be considered in the private dental clinic settings.

CLINICAL SIGNIFICANCE

This is an opportunity to collaborate with other health care professionals to support overall health monitoring/advice; a common risk factor strategy as recommended by the WHO. Future research is merited for this new initiative particularly perceptions of: dental teams' on healthy weight management, longitudinal interventions, NHS, children/parents and separate obese groups.

The Use of Picture Cards to Elicit Postgraduate Dental Student Feedback

The aim of this study was to elicit information about the use of picture cards to stimulate student feedback following a postgraduate dental course. Twenty-nine general dental practitioners (GDPs) volunteered for the study. Following an explanation of how this style of feedback worked, students were asked to choose a picture card from those available and use that image to stimulate their feedback. An independent interviewer introduced the topic and gathered comments in the form of qualitative data, generated by pre-formed questions. 93% (n = 26) questionnaires were completed and returned. 77% (n = 20) GDPs reported enjoying giving their feedback by 'picture card' technique; 83% (n = 20) reported this form of feedback stimulated their thoughts. Qualitative data were analysed thematically. Some GDPs felt the picture cards helped them formulate their feedback, others felt being able to give feedback to a third party they did not know was beneficial and giving feedback as a group was helpful. This novel approach of using picture cards to stimulate feedback was well received by these GDPs. A mixed result as to the value of this style of feedback was evident. A group feedback session facilitated by a stranger was considered to be a valuable approach to take.

Comparison of traditional and simplified methods for repairing CAD/CAM feldspathic ceramics

PURPOSE

To evaluate the adhesion to CAD/CAM feldspathic blocks by failure analysis and shear bond strength test (SBSt) of different restorative systems and different surface treatments, for purpose of moderate chipping repair.

MATERIALS AND METHODS

A self-adhering flowable composite (Vertise Flow, Kerr) containing bi-functional phosphate monomers and a conventional flowable resin composite (Premise Flow, Kerr) applied with and without adhesive system (Optibond Solo Plus, Kerr) were combined with three different surface treatments (Hydrofluoric Acid Etching, Sandblasting, combination of both) for repairing feldspathic ceramics. Two commercial systems for ceramic repairing were tested as controls (Porcelain Repair Kit, Ultradent, and CoJet System, 3M). SBSt was performed and failure mode was evaluated using a digital microscope. A One-Way ANOVA (Tukey test for post hoc) was applied to the SBSt data and the Fisher's Exact Test was applied to the failure analysis data.

RESULTS

The use of resin systems containing bi-functional phosphate monomers combined with hydrofluoric acid etching of the ceramic surface gave the highest values in terms of bond strength and of more favorable failure modalities.

CONCLUSION

The simplified repairing method based on self-adhering flowable resin combined with the use of hydrofluoric acid etching showed high bond strength values and a favorable failure mode. Repairing of ceramic chipping with a self-adhering flowable resin associated with hydrofluoric acid etching showed high bond strength with a less time consuming and technique-sensitive procedure compared to standard procedure.

The Impact of a Postgraduate Learning Experience on the Confidence of General Dental Practitioners

This study aimed to explore the relationship between participating in a learning experience and the ensuing changes in confidence. A self-selected group of General Dental Practitioners (GDPs) entered a five-year, part-time postgraduate master’s training programme in restorative dentistry. Confidence in communication with patients and technical skills were measured at the start of the programme by questionnaire and at the conclusion of the programme by questionnaire and personal interview. A total of 72 clinicians started the programme; 27% (n = 20) completed the master’s degree. Assessment of confidence revealed a spread from 4/10 to 10/10 for communication with patients and clinical skills in restorative dentistry before the programme started. A total of 15% (n = 11) volunteered for interview. Analysis of qualitative data revealed (i) a perceived increase in confidence from all clinicians; (ii) a perceived greater ability to treat patients; (iii) an increase in treatment options being offered to patients; (iv) a perceived increase in treatment uptake by patients; and (v) greater job opportunities. The study showed a positive relationship between the learning experience and the perceived increase in confidence of clinicians. The increase in confidence manifested itself in better communication and clinical skills.

An investigation of complete denture teaching in the UK: part 2. The DF1 experience

AIM

This paper, the second in a series of two (see 2013; 215: 177-181), investigates the opinions of a cohort of dental foundation year 1 (DF1) practitioners regarding their skills and competence in relation to their educational background in complete dentures.

MATERIALS AND METHODS

With the permission of the Dean of the London Deanery a questionnaire was emailed to the ten London Foundation year 1 training schemes for distribution to approximately 100 DF1s. Five schemes responded with total of 56 completed questionnaires (56%).

RESULTS

The average number of complete dentures made as undergraduates was three. Forty-six percent had no experience in making copy dentures. An average of 2 (median 2.05) immediate replacement dentures were made; only 10% made 8-15 dentures. None had experience in implant-supported dentures. Thirty-five percent enjoyed their undergraduate training whereas 45% did not. Thirty-seven percent felt that their training had given them experience and confidence in complete dentures but 32% were of the opposite opinion. Sixty-three percent felt complete dentures were an important or very important aspect of dentistry. Six percent completely disagreed. The majority were confident in making impressions while 39% lacked confidence in registering jaw relations. Thirty-five percent were confident with chairside adjustments at the intermediary treatment stages but 28% were not. Sixty-three percent were confident in the fitting of new dentures and 64% with the after-care. There was no significant gender difference in the responses. There was a significant difference between the London and non-London trained DF1s. The London trained respondents made significantly fewer dentures than the non-London trained cohort. The latter also rated complete denture treatment as being more important. The comments section revealed that 43% felt that they had a lack of experience; only 5% were confident, 16% thought that complete denture treatment would become obsolete and only 5% recognised the continuing importance of complete denture treatment.

CONCLUSION

There is a disparity between the comments which indicate a lack of confidence in complete denture treatment and the response to the questionnaire. Other authors have commented on the lack of experience that has resulted in new graduates entering vocational training with little confidence in complete denture techniques. This report has highlighted these difficulties with respect to a current cohort of DF1s.

Influence of coloring procedure on flexural resistance of zirconia blocks

STATEMENT OF PROBLEM

The white color of zirconia limits the possibility of a natural-looking restoration. Industrially precolored blocks and green-stage coloring liquids are used to obtain shaded zirconia. Several authors have reported that pigments may negatively affect the mechanical characteristics of the material.

PURPOSE

The purpose of this in vitro study was to investigate the effect of a recently marketed coloring system on the flexural strength (σ), Weibull characteristic strength (σ0), and Weibull modulus (m) of a zirconia for computer-aided design/computer-aided manufacturing (CAD/CAM) systems.

MATERIAL AND METHODS

Noncolored white blocks (In-Ceram YZ), industrially precolored blocks (In-Ceram YZ col. LL1p), and green-stage infiltration-shaded blocks in 4 colors (In-Ceram YZ Coloring Liquids) were tested. Industrially precolored specimens (n = 30) were assigned to the PREC group. Noncolored specimens were divided into 5 groups (n = 30). Group CNTR was not treated (control). Groups INF-N, INF-L, INF-M, and INF-I were subject to green-stage infiltration (neutral, light, medium, and intense, respectively). Specimens were tested in a 3-point bending apparatus following ISO 6872:2008 specifications. Data were analyzed by 1-way ANOVA.

RESULTS

The calculated flexural strengths (MPa) were CNTR 1232.56 ± 103.91; PREC 1215.16 ± 141.42; INF-N 1280.72 ± 160.10; INF-L 1218.92 ± 78.63; INF-M 1153.71 ± 176.80; and INF-I 1248.46 ± 111.73. No statistically significant differences were found among the tested groups (P = .195).

CONCLUSIONS

Unlike what has been reported for other combinations of zirconia and coloring liquids, the coloring technique tested in the present study did not negatively influence the flexural characteristics of the tested zirconia.

Clinical decision-making after endodontic instrument fracture

When a file fractures during root canal treatment there are several treatment options available to the clinician. The definitive management should be based on a thorough knowledge of the success rates of each treatment option, balanced against potential risks of removal or file retention. Although integration of modern techniques into endodontic practice has improved the clinician's ability to remove fractured files, removal may not always be possible or even desirable. The aim of the third and final review in this series was to analyse the literature with regard to the management of fractured files. Analysis of the literature demonstrated that the presence of a fractured instrument need not reduce the prognosis if the case is well treated and there is no evidence of apical disease. Therefore, in cases without apical disease removal of the file may not be necessary and retention or bypass should be considered. If apical disease is present, file fracture significantly reduces prognosis indicating a greater need to attempt file removal or bypass. A plethora of different methods have been employed to remove fractured instruments and although successful, these techniques usually require the use of the operating microscope and specialist care. Removal of a fractured file is not without considerable risk, particularly in the apical regions of the root canal, therefore, leaving the fragment in situ should be considered if referral is not possible. Finally, it is imperative that the patient is informed (accompanied by appropriate record keeping) if instrument fracture occurs during treatment or if a fractured file is discovered during a routine radiographic examination.

Flexural resistance of Cerec CAD/CAM system ceramic blocks. Part 2: Outsourcing materials

PURPOSE

To test different Cerec CAD/CAM system ceramic blocks, comparing mean flexural strength (sigma), Weibull modulus (m), and Weibull characteristic strength (sigma0) in an ISO standardized set-up.

METHODS

Following the recent ISO Standard (ISO 6872:2008), 11 types of ceramic blocks were tested: IPS e.max CAD MO, IPS e.max CAD LT and IPS e.max CAD HT (lithium disilicate glass-ceramic); In-Ceram SPINELL, In-Ceram Alumina and In-Ceram Zirconia (glass-infiltrated materials); inCoris AL and In-Ceram AL (densely sintered alumina); In-Ceram YZ, IPS e.max Zir-CAD and inCoris ZI (densely sintered zirconia). Specimens were cut out from ceramic blocks, finished, crystallized/infiltrated/sintered, polished, and tested in a three-point bending test apparatus. Flexural strength, Weibull characteristic strength, and Weibull modulus were obtained.

RESULTS

A statistically significant difference was found (P < 0.001) among lithium disilicate glass-ceramic (sigma = 272.6 +/- 376.8 MPa, m = 6.2 +/- 11.3, sigma0 = 294.0 +/- 394.1 MPa) and densely sintered alumina (sigma = 441.8 +/- 541.6 MPa, m = 11.9 +/- 19.0, sigma0 = 454.2 +/- 565.2 MPa). No statistically significant difference was found (P = 0.254) in glass infiltrated materials (sigma = 376.9 +/- 405.5 MPa, m = 7.5 +/- 11.5, sigma0 = 393.7 +/- 427.0 MPa). No statistically significant difference was found (P = 0.160) in densely sintered zirconia (sigma = 1,060.8 +/- 1,227.8 MPa, m = 5.8 +/- 7.4, sigma0 = 1,002.4 +/- 1,171.0 MPa). Not all the materials tested fulfilled the requirements for the clinical indications recommended by the manufacturer.

Flexural resistance of Cerec CAD/CAM system ceramic blocks. Part 1: Chairside materials

PURPOSE

This study tested the materials available on the market for Cerec CAD/CAM, comparing the mean flexural strength in an ISO standardized set-up, since the ISO standard for testing such materials was issued later than the marketing of the materials tested.

METHODS

Following the recent Standard ISO 6872:2008, eight types of ceramic blocks were tested: Paradigm C, IPS Empress CAD LT, IPS Empress CAD Multi, Cerec Blocs, Cerec Blocs PC, Triluxe, Triluxe Forte, Mark II. Specimens were cut out from ceramic blocks, finished, polished, and tested in a three-point bending test apparatus until failure. Flexural strength, Weibull characteristic strength, and Weibull modulus, were calculated.

RESULTS

The results obtained from the materials for flexural strength were IPS Empress CAD (125.10 +/- 13.05), Cerec Blocs (112.68 +/- 7.97), Paradigm C (109.14 +/- 10.10), Cerec Blocs PC (105.40 +/- 5.39), Triluxe Forte (105.06 +/- 4.93), Mark II (102.77 +/- 3.60), Triluxe (101.95 +/- 7.28) and IPS Empress CAD Multi (100.86 +/- 15.82). All the tested materials had a flexural strength greater than 100 MPa, thereby satisfying the requirements of the ISO standard for the clinical indications of the materials tested. In all tested materials the Weibull characteristic strength was greater than 100 MPa.

Spectrophotometric evaluation of color match of three different porcelain systems for all-ceramic zirconia-based restorations

PURPOSE

To determine by a spectrophotometric analysis the variations in color between the intended and the fabricated shades of three different porcelain systems when applied in a standardized thickness on a zirconia core.

METHODS

Three porcelain systems for zirconia based restorations, Ivoclar IPS e.max Ceram, VITA VM9, and Creation Zi-F were tested. Nine disc-shaped (15 mm diameter, 0.5 mm thickness) specimens of VITA YZ zirconia core per group were made comprising a total of 27 discs. Three different shades (A2, A3, A4) of the Vitapan Classical shade guide were investigated. The porcelain veneer total thickness was set at 1.0 mm in all groups. The porcelain stratification was made by applying calibrated layers of porcelain. Thicknesses of single porcelain layers were calculated from drawings retrieved from the manufacturers' instructions. Color parameters (L*, a*, b*) of veneered specimens were measured by a clinical spectrophotometer. Color differences (deltaE) were calculated using a color difference formula. Two-way ANOVA and Tukey's test were used to analyze the data.

RESULTS

The mean color differences for the three ceramic systems, Ivoclar IPS e.max Ceram, VITA VM9 and Creation Zi-F were respectively 4.1, 2.7 and 3.2, regardless of the shades. VITA VM9 resulted in the best average shade matching among the porcelain systems, even if results with shade A3 were considerably worse than shades with A2 and A4 (P<0.05). Color matching appeared not to be shade dependent (P>0.05) among the tested shades.

Color correspondence of different batches of TriLuxe CAD/CAM ceramic blocks

TriLuxe ceramic blocks for chairside CAD/CAM procedures are color layered to allow natural esthetics, and only require subsequent glazing. The purpose of this study was to compare color repeatability of different batches of TriLuxe blocks. The three commercially available shades (1M2C, 2M2C, 3M2C) of TriLuxe blocks for the Cerec CAD/CAM system were examined. For each of the three colors, three different batches were tested, 5 blocks each. The measurements were made using a spectrophotometer equipped with an integrating sphere using the CIELab* colorimetric system. One-way ANOVA showed that the factor "Production Batch" was not statistically significant. Regarding deltaE, none of the 315 color comparisons (neither within the same shade, nor between specimens of the same batch, nor between specimens from different batches) exceeded the proposed deltaE = 3.3 threshold for clinical acceptability. All the different batches of the different shades of VITA TriLuxe blocks for the Cerec system showed the high degree of color correspondence necessary in industrially prefabricated CAD/CAM blocks.

The role of gingival mechanoreceptors in the reflex control of human jaw-closing muscles

Electromyographic (EMG) experiments were undertaken to investigate the jaw reflexes evoked by activation of gingival receptors in 12 humans. EMG recordings were made from an active masseter muscle whilst ramp-plateau mechanical stimuli were applied to the gingiva. Stimuli with a constant rate of rise (0.2 N/msec) and a variable plateau force (up to 2 N), evoked a complex set of short- and long-latency inhibitory and excitatory responses. These occurred as a sequence of inhibition-excitation-inhibition-excitation, although not all of these elements were seen on every occasion. The median thresholds of these four responses ranged from 0.5 to 1 N but overall there were no significant differences between them (p > 0.05, Friedman's ANOVA). In other experiments, the same reflexes were recorded in response to application to the gingiva of 1 N ramp-plateau stimuli (5 msec rise time) and 1 N tap stimuli applied to the adjacent tooth. The application of a local anaesthetic agent to the stimulated gingiva produced reductions in the mean magnitude of almost all the responses but these were significant (p < 0.05; ANOVA) only for the long-latency inhibitions evoked by ramping the gingiva and the long-latency excitations evoked by either stimulus. It is concluded that mechanoreceptors in the gingiva can mediate long-latency inhibitory and excitatory jaw reflexes, and that these receptors may also contribute to long-latency reflexes evoked by tapping teeth. The scarcity of effects of gingival anaesthesia on the short-latency reflexes may be due to such responses being mediated by receptors deeper in the periodontium.

The roles of periodontal ligament mechanoreceptors in the reflex control of human jaw-closing muscles

Controlled mechanical stimuli were applied to an upper central incisor tooth in 19 human subjects and the resulting reflexes in the ipsilateral masseter muscle were examined electromyographically. In most cases the force profile of the stimuli consisted of a ramp leading to a sustained plateau at an intensity of 1 N. In addition 1 N tap stimuli were employed in some subjects. The 1 N ramp stimuli with a rise time of < or = 20 ms consistently evoked a single, short-latency (approximately 12 ms), inhibitory reflex which was often followed by an excitatory wave. The ramp stimuli with shorter rise times produced larger responses than those produced by ramp stimuli with longer rise times. By contrast the tap stimuli elicited a sequence of responses consisting of inhibitory-excitatory-inhibitory-excitatory components. The first inhibitory and excitatory responses evoked by tap stimuli had latencies similar to those of the responses evoked by the ramp stimuli. The latencies of the inhibitory responses evoked by 1 N ramps with rise times ranging between 2.5 and 20 ms did not vary significantly with the rise time. Consistent with this observation it was found that the median threshold force for evoking the short-latency inhibitory reflex was only 0.25 N. This was significantly less than the threshold for the excitatory response (median: 0.75 N). The responses to ramp-plateau forces were not dependent on the level of preloading of the tooth (at least within the range tested: < 0.25 to 1 N). These findings provide evidence that mechanoreceptors in the periodontal ligament contribute to the control of human jaw-closing muscles, notably to short-latency reflex responses. It may be concluded that the additional reflex responses produced by tapping stimuli result from the activation of receptors elsewhere due to vibration.

Electrosurgery in restorative Dentistry: 2. Clinical applications

Electrosurgery techniques have been used in dentistry as an aid to soft tissue management for nearly 60 years. However, it was not until the late 1960s that the principles of electrosurgery were understood and improved equipment became available. Part 1 of the two-part series covered the theory behind using this technique. Part 2 will now discusses the clinical applications.

Electrosurgery in restorative dentistry: 1. Theory

Electrosurgery techniques have been used in dentistry as an aid to soft tissue management for nearly 60 years. However, it was not until the late 1960s that the principles of electrosurgery were understood and improved equipment became available. Part 1 of this two-part series covers the theory behind using this technique. Part 2 will discuss the clinical applications.