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.

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.

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.

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.

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.

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.

An in vivo and in vitro investigation of the use of ICDAS, DIAGNOdent pen and CarieScan PRO for the detection and assessment of occlusal caries in primary molar teeth.

OBJECTIVES: The aim of this study was to investigate the in vivo and in vitro validity of International Caries Detection and Assessment System (ICDAS), DIAGNOdent pen and CarieScan PRO in the detection and assessment of occlusal caries in primary teeth. METHODS: Sixty-four molars were assessed using all three systems under standardised in vivo conditions. They were then extracted and assessed by two examiners in vitro along with an additional 38 teeth (102 teeth in total from 45 children). Downer's histological scoring criterion was the validation gold standard. Sensitivity, specificity, positive and negative likelihood ratios and area under the receiver-operator curves were calculated for all caries and dentine caries. Repeatability was analysed using Cohen's Kappa and the performance of the systems between in vivo and in vitro settings by the same examiner were compared. RESULTS: ICDAS showed the highest validity and repeatability. The DIAGNOdent pen's overall clinical validity was comparable to that of ICDAS, but it demonstrated only moderate repeatability. CarieScan PRO had negligible validity in vivo, and there was no relationship between in vivo and in vitro parameters. CONCLUSIONS: The in vivo results of ICDAS and DIAGNOdent pen were satisfactory and comparable to those obtained in vitro, with ICDAS performing better. The CarieScan PRO performed poorly under both conditions. CLINICAL RELEVANCE: ICDAS should be the index of choice when detecting and assessing occlusal caries in the primary dentition, and in vitro data can be safely extrapolated in vivo. The DIAGNOdent pen must be employed with caution. Currently, the CarieScan PRO is unsuitable for use in the primary dentition.

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.

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.

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.

3D Printed Materials for Permanent Restorations in Indirect Restorative and Prosthetic Dentistry: A Critical Review of the Literature.

The objective of this study was to review the scientific evidence currently available on 3D printable materials and 3D printing technologies used for the fabrication of permanent restorations, focusing on material properties that are clinically relevant. A literature search was performed on four databases (MEDLINE/PubMed, Scopus, Cochrane Library, Web of Science) for articles published from January 2013 until November 2023, using a combination of free words: (restorative dentistry OR prosthetic dentistry) AND (3D printing OR additive manufacturing OR rapid prototyping) AND materials. Two reviewers screened titles and/or abstracts of 2.468 unique studies. In total, 83 studies were selected for full-text reading, from which 36 were included in the review. The assessed variables were mechanical properties, reporting in most of the cases positive results, dimensional accuracy and fit, reporting conflicting results with a predominance of positive, aesthetic properties, with positive reports but scarcely addressed, and biological properties, almost unexplored in independent studies. Despite numerous studies with positive results in favor, papers with negative outcomes were also retrieved. Aesthetic and biological properties are conversely still mostly unexplored. There remains a lack of conclusive evidence for viable 3D printable restorative and prosthodontic materials for permanent restorations. Research should be strengthened by defining international standards for laboratory testing and, where pre-clinical data are promising, conducting clinical trials.

Evaluation of postgraduate foundation training for dental therapists: does participation enhance career prospects?

Objectives This study explored the value of dental therapy foundation training (DTFT) in the UK and how participation influenced career prospects.Aims To examine the efficacy of postgraduate foundation training for dental therapists (DTs) and evaluate whether participation increased clinical confidence. To investigate whether participation in the scheme enhanced career prospects and to determine barriers encountered by DTs in securing suitable positions, inclusive of COVID-19 restrictions.Methods The study used a survey incorporating open, closed, Likert-scale and multiple-choice questions. Quantitative data were analysed with IBM SPSS Statistics v26. Analysis of qualitative data was undertaken by two researchers. Final themes and subthemes were confirmed following round table discussions.Results A total of 94 survey responses were received: 61 from DTs who had not undertaken DTFT (Group A) and 33 who had undertaken DTFT (Group B). Most respondents were female (95%) with a mean age of 33.8 and 32.9 years, respectively. In total, 58.3% of Group A respondents did not believe that completing DTFT would have enhanced their career prospects, whereas 63.6% of Group B said that they gained a position as a result of completing DTFT. Participation in DTFT increased perceived clinical confidence in Group B and 81.8% were likely to recommend DTFT to their peers. A total of 12 major themes and 13 subthemes were identified.Conclusions DTFT schemes were considered a valuable educational experience which increased clinical confidence. Participation may have enhanced career prospects. Barriers were encountered by DTs when seeking work, regardless of participation in DTFT.

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.

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.

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.

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.

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.

Translucency of CAD/CAM and 3D Printable Composite Materials for Permanent Dental Restorations.

The aim of the study was to compare the translucency of CAD/CAM and printable composite materials for fixed dental prostheses (FDP). Eight A3 composite materials (7 CAD/CAM and 1 printable) for FPD were used to prepare a total of 150 specimens. CAD/CAM materials, all characterized by two different opacity levels, were: Tetric CAD (TEC) HT/MT; Shofu Block HC (SB) HT/LT; Cerasmart (CS) HT/LT; Brilliant Crios (BC) HT/LT; Grandio Bloc (GB) HT/LT; Lava Ultimate (LU) HT/LT, Katana Avencia (KAT) LT/OP. The printable system was Permanent Crown Resin. 1.0 mm-thick specimens were cut from commercial CAD/CAM blocks using a water-cooled diamond saw, or 3D printed. Measurements were performed using a benchtop spectrophotometer with an integrating sphere. Contrast Ratio (CR), Translucency Parameter (TP), and Translucency Parameter 00 (TP00) were calculated. One Way ANOVA followed by Tukey test for post hoc were performed for each of the translucency system. The tested materials exhibited a wide range of translucency values. CR ranged from 59 to 84, TP from 15.75 to 8.96, TP00 from 12.47 to 6.31. KAT(OP) and CS(HT) showed, respectively, the lowest and highest translucency for CR, TP and TP00. Due to the significant range of reported translucency values, clinicians should exercise caution when choosing the most appropriate material, especially considering factors such as substrate masking, and the necessary clinical thickness.

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.