Factors influencing success rate of ceramic veneers on endodontically treated anterior teeth: A systematic review.

STATEMENT OF PROBLEM: More conservative restorative approaches have been advocated for nonvital anterior teeth as an alternative to complete coverage crowns to maximize the preservation of tooth structure. Systematic reviews that investigated factors influencing the success rate of porcelain veneers on endodontically treated anterior teeth are lacking. PURPOSE: The purpose of this systematic review was to investigate factors influencing the success rate of porcelain veneers on endodontically treated anterior teeth. MATERIAL AND METHODS: Searches were performed across Medline/PubMed, Google Scholar, Scopus, and Web of Science electronic databases. In addition, articles were hand searched from references of systematic reviews concerning porcelain veneers and endodontically treated teeth. RESULTS: After screening and applying the eligibility, inclusion, and exclusion criteria, 7 articles met the inclusion criteria. Factors that could positively influence the success rate of endodontically treated anterior veneered teeth were immediate dentin sealing, labially positioning of the endodontic access cavity, and incorporating fiber posts. CONCLUSIONS: The use of fiber posts and labial positioning of the endodontic access cavity could positively influence the success rate of porcelain veneers on endodontically treated teeth. The effect of immediate dentin sealing on the survival rate of endodontically treated veneered teeth is still unclear and further research is needed.

Perception of health and educational risks amongst dental students and educators in the era of COVID-19.

OBJECTIVE: To investigate the perceived educational and health risks associated with the COVID-19 pandemic amongst dental students and educators. METHODS: A 17-item electronic survey was sent to 496 undergraduate dental students and 53 clinical faculty members who attended clinical sessions during the outbreak period. The survey explored various aspects related to primary sources and prevention of disease exposure, dental management of suspected cases, impact of COVID-19 on students' clinical performance and effects of suspension of educational activities on academic performance and clinical competence. RESULTS: The response rate of the students' was 60.7% (n = 301). The majority of students reported that performing clinical work during the outbreak posed significant health concerns, resulted in a significant stress and negatively affected their clinical performance. The majority of students believed that aerosols generated during dental procedures are the major source for disease exposure and universal protective equipment is not effective for prevention. The decision to suspend teaching activities was supported by 89% of the students. Opinions were divided regarding the impact of the suspension on the academic performance and clinical competence. Educational videos were the most preferred form of distance education. The response rate of faculty members was 60.4% (n = 32). Responses of faculty members were similar to students, though fewer concerns were reported regarding the risk of disease transmission. All respondents agreed that extra-precautionary measures are required to ensure optimum protection against disease exposure. CONCLUSIONS: The recent COVID-19 outbreak has adversely affected various elements of dental education. High levels of major health risk perception were noted amongst students and educators. The interruption to academic and clinical activities may lead to an inevitable skill deficit within the new generation of dental graduates. Educators are under significant pressure to accommodate abrupt changes in teaching methods, find solutions to mitigate skill deficit and ensure safe clinical practice once clinical activities are resumed.

A randomized controlled clinical trial comparing the use of displacement cords and aluminum chloride paste.

OBJECTIVES: This clinical study measured the change in opening and height of the displaced gingiva using paste and cord retraction materials for definitive impression making of natural teeth and assessed if they were comparable and clinically acceptable. METHODS: Impressions of 4 maxilla premolars from 10 participants were taken using a split-mouth protocol. All participants were free of periodontal disease, had a thick biotype, a minimal of 3 mm height of keratinized gingival tissue and gingival sulci depths of 2 mm. The bleeding index (BI), gingival index (GI) plaque index (PI), sulcular depth, level of attachment and tooth sensitivity were recorded at baseline, just after retraction, at 24 hours and at 2 weeks. Impressions were poured in stone and then after initial analysis were cross-sectioned to allow measurements of the gingival height change and gap size to be recorded. RESULTS: The paste produced a slightly smaller gap compared to the cord (0.041 mm less, P = .014) whilst the mean displacement for the cord was 0.282 mm and paste was 0.241 mm respectively. Gingival height with the paste was 0.047 mm lower than that achieved by the cord (P = .208). CONCLUSIONS: Cord and paste retraction produced comparable clinically acceptable gingival gaps, with the cord producing statistically larger gap size. CLINICAL SIGNIFICANCE: The cord and paste retraction materials produced comparable clinically acceptable gingival retraction.

Patient satisfaction with esthetics, phonetics, and function following implant-supported fixed restorative treatment in the esthetic zone: A systematic review.

OBJECTIVE: To determine patient satisfaction with esthetics, phonetics, and function following implant-supported fixed restorative treatment in the esthetic zone by measuring the Oral Health Related Quality of Life (OHRQoL). MATERIALS AND METHODS: This systematic review follows the "Preferred reporting items for systematic review and meta-analysis protocols" (PRISMA-P) 2015 statement. Studies were searched in the databases Ovid, PubMed, Web of Science, Scopus, and the Cochrane Library. The quality of the studies included in the review was scored using the GRADE system. The impact of the findings was analyzed by calculating effect size and standardization of results across different OHRQoL measurements was achieved by calculating the percentage equivalent. RESULTS: A total of 13 studies were selected to be included in his systematic review after application of the inclusion criteria. A total of six studies recorded pre- and post-treatment OHRQoL results, while the remaining seven studies provided only post-treatment results. CONCLUSIONS: This review concluded that implant-supported fixed restorations in the esthetic zone have an overall positive impact on OHRQoL. However, patient satisfaction from this treatment reduced as the number of missing teeth replaced by implants was increased. CLINICAL SIGNIFICANCE: When implant-supported fixed restorations are being planned in the esthetic zone, dentists need to consider the patient's perception and the subsequent impact of these restorations on the patient's quality of life. Clinicians can be assured that patient OHRQoL will increase; however, clinicians should also keep in mind the importance of the gingival frame. Furthermore, they should be aware of the challenges when planning cases with larger numbers of implants in the esthetic zone as this could lead to a lowering of a patient QoL.

Access and barriers to oral health care for dependent elderly people living in rest homes.

AIM: To report New Zealand rest home (rest home is the New Zealand term for residential aged care facilities where dependent, institutionalised, elderly people reside.) managers' opinions on access and barriers to oral health care for rest home residents. METHODS: An exploratory study using qualitative descriptive methods. Eleven rest home managers in a region of New Zealand were interviewed about admission assessments for new residents, oral health care, availability of dental facilities, staff training in oral hygiene, residents' nutritional needs and oral hygiene aids. RESULTS: Interviews with managers indicated that rest homes have no policies for the provision of oral health care and only arrange dental check-ups or treatment when requested by residents or family. Barriers to accessing care include making appointments, availability of staff and transport particularly for bedridden patients. Staff receive basic oral hygiene training only and face resistance to oral hygiene from some residents. No homes had a dental chair at their premises. All rest homes stocked oral hygiene aids such as toothbrushes and toothpastes. Electric toothbrushes were not generally promoted with cost being a key factor. CONCLUSION: While rest home managers were aware of the importance of good oral health, there are barriers to care. Finance is a challenge as dental care is not publicly funded and many residents rely on a limited income. Recommendations include policy changes to better fund oral health, specific oral health training for rest home staff, provision of mobile dental services to rest homes and the inclusion of gerodontology in the dental school curriculum.

Graduate mobility: Where do dentistry graduates choose to practise?

BACKGROUND AND OBJECTIVE: The international higher education market has grown and developed rapidly. International students generate attractive income for host universities, and gaining an international education benefits students in an increasingly globalised world. However, there is little research regarding where international students intend to work and settle beyond graduation. This study investigated where dentistry students intended to practise after graduation, and whether international students who graduated between 2001 and 2016 are currently practising in their host country (New Zealand) or have migrated overseas. METHODS: A cross-sectional survey was used to investigate current students' intended destination of practice after graduation. Additionally, names of international graduates since 2001 were matched against the 2017 register of practitioners to determine if they were currently registered to practise in their host country. A frequency and bivariate analysis was conducted. RESULTS: Almost 64% of current international students indicated their intention to stay in their host country after graduation. However, only 22% of graduates since 2001 were currently practising in New Zealand. The number of international graduates who registered to practise in New Zealand increased between 2001 and 2016. CONCLUSION: Less than one-quarter of international graduates were currently practising in their host country; however, longitudinal data showed that this is an increasing trend. These findings can be used to inform how we might prepare current and future graduates for both local and globalised labour markets.

Dental complications of gastro-oesophageal reflux disease: guidance for physicians.

There is potential for gastro-oesophageal reflux disease (GORD) to be under-diagnosed by physicians. A quick, focused examination, requiring no special equipment, of a patients' dentition can assist in making a more accurate diagnosis where GORD is suspected. Guidance is provided for physicians as to what intra-oral signs are suggestive of intrinsic dental erosion, which is a clinical feature of GORD and its associated conditions. Use of this information will, it is suggested, improve outcomes for patients where GORD is suspected.

Attitudes of dentists toward denture adhesives: A questionnaire survey in Greece.

STATEMENT OF PROBLEM: The attitudes of dental professionals toward denture adhesives (DAs) require further investigation. PURPOSE: The purpose of this survey was to assess the attitudes of dentists in Greece toward DAs and the possible effects of sex, age, training, and awareness level on these attitudes. MATERIAL AND METHODS: An 18-item questionnaire in the Greek language concerning the use of DAs by dentists in the metropolitan area of Athens, Greece was distributed on line. Its URL address was emailed to 793 randomly chosen dentists in the area, 438 of whom filled out and submitted a valid questionnaire (55.2% response rate). Data for each item were statistically analyzed for their associations with sex, age, training, and awareness level by the chi-square test for independence (α=.05). RESULTS: The results showed that 61.5% of general practitioners and 49% of specialist prosthodontists recommend the use of DAs. Their continuous use was recommended most frequently (46.9%), mainly in the cream form (93.8%). Their use was recommended not only for patients wearing older dentures (60.2%) but also for patients with newly fabricated ones (61.9%) to assist their adaptation to dentures (42.2%). Associations were found between a few only items and sex (Q07, Q11a,b), age (Q13), training (Q11q,b), and awareness level (Q11a,b,d,e) (P<.05). CONCLUSIONS: This survey shows that in the metropolitan area of Athens, Greece, a significant proportion of dentists (60.3%) recommend the use of DAs and do so more often as a continuous regimen for both existing and new denture wearers. Sex, age, training, and awareness level proved to be factors affecting only a few dentists' attitudes.

Replacement versus repair of defective restorations in adults: resin composite.

BACKGROUND: Composite filling materials have been increasingly used for the restoration of posterior teeth in recent years as a tooth-coloured alternative to amalgam. As with any filling material composites have a finite life-span. Traditionally, replacement was the ideal approach to treat defective composite restorations, however, repairing composites offers an alternative more conservative approach to the tooth structure where restorations are partly still serviceable. Repairing the restoration has the potential of taking less time and may sometimes be performed without the use of local anaesthesia hence it may be less distressing for a patient when compared with replacement. OBJECTIVES: To evaluate the effects of replacing (with resin composite) versus repair (with resin composite) in the management of defective resin composite dental restorations in permanent molar and premolar teeth. SEARCH METHODS: For the identification of studies relevant to this review we searched the Cochrane Oral Health Group's Trials Register (to 24 July 2013); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 6); MEDLINE via OVID (1946 to 24 July 2013); EMBASE via OVID (1980 to 24 July 2013); BIOSIS via Web of Knowledge (1969 to 24 July 2013); Web of Science (1945 to 24 July 2013); and OpenGrey (to 24 July 2013). Researchers, experts and organisations known to be involved in this field were contacted in order to trace unpublished or ongoing studies. No restrictions were placed on the language or date of publication when searching the electronic databases. SELECTION CRITERIA: Trials were selected if they met the following criteria: randomised controlled trial (including split-mouth studies), involving replacement and repair of resin composite restorations in adults with a defective molar restoration in a permanent molar or premolar teeth. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed titles and abstracts for each article identified by the searches in order to decide whether the article was likely to be relevant. Full papers were obtained for relevant articles and both review authors studied these. The Cochrane Collaboration statistical guidelines were to be followed for data synthesis. MAIN RESULTS: The search strategy retrieved 298 potentially eligible studies, after de-duplication. After examination of the titles and abstracts, full texts of potentially relevant studies were retrieved but none of the retrieved studies met the inclusion criteria of the review. AUTHORS' CONCLUSIONS: There are no published randomised controlled trials relevant to this review question. There is therefore a need for methodologically sound randomised controlled trials that are reported according to the Consolidated Standards of Reporting Trials (CONSORT) statement (www.consort-statement.org/). Further research also needs to explore qualitatively the views of patients on repairing versus replacement and investigate themes around pain, anxiety and distress, time and costs.

Replacement versus repair of defective restorations in adults: amalgam.

BACKGROUND: Amalgam is a common filling material for posterior teeth, as with any restoration amalgams have a finite life-span. Traditionally replacement was the ideal approach to treat defective amalgam restorations, however, repair offers an alternative more conservative approach where restorations are only partially defective. Repairing a restoration has the potential of taking less time and may sometimes be performed without the use of local anaesthesia hence it may be less distressing for a patient when compared with replacement. Repair of amalgam restorations is often more conservative of the tooth structure than replacement. OBJECTIVES: To evaluate the effects of replacing (with amalgam) versus repair (with amalgam) in the management of defective amalgam dental restorations in permanent molar and premolar teeth. SEARCH METHODS: For the identification of studies relevant to this review we searched the Cochrane Oral Health Group's Trials Register (to 5 August 2013); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 7); MEDLINE via OVID (1946 to 5 August 2013); EMBASE via OVID (1980 to 5 August 2013); BIOSIS via Web of Knowledge (1969 to 5 August 2013); Web of Science (1945 to 5 August 2013) and OpenGrey (to 5 August 2013). Researchers, experts and organisations known to be involved in this field were contacted in order to trace unpublished or ongoing studies. No restrictions were placed on the language or date of publication when searching the electronic databases. SELECTION CRITERIA: Trials were selected if they met the following criteria: randomised controlled trial (including split-mouth studies), involving replacement and repair of amalgam restorations in adults with a defective restoration in a molar or premolar tooth/teeth. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed titles and abstracts for each article identified by the searches in order to decide whether the article was likely to be relevant. Full papers were obtained for relevant articles and both review authors studied these. The Cochrane Collaboration statistical guidelines were to be followed for data synthesis. MAIN RESULTS: The search strategy retrieved 201 potentially eligible studies after de-duplication. After examination of the titles and abstracts, full texts of the relevant studies were retrieved but none of these met the inclusion criteria of the review. AUTHORS' CONCLUSIONS: There are no published randomised controlled trials relevant to this review question. There is therefore a need for methodologically sound randomised controlled trials that are reported according to the Consolidated Standards of Reporting Trials (CONSORT) statement (www.consort-statement.org/). Further research also needs to explore qualitatively the views of patients on repairing versus replacement and investigate themes around pain, distress and anxiety, time and costs.

Effect of carbamide peroxide on biomechanical properties of vacuum-formed retainers: A split-mouth randomized controlled trial.

OBJECTIVE: To investigate the effect of tooth whitening on biomechanical properties of vacuum-formed retainers (VFRs). METHODS: Using a split-mouth, randomised controlled trial design, thirty participants were randomly allocated to receive whitening on either the upper or the lower arch, using 10 % carbamide peroxide for two weeks. Biomechanical properties such as hardness, tensile strength, and surface roughness were assessed two weeks after whitening was completed. RESULTS: Tensile strength of the whitening arch (mean ± SD: 40.93 ± 3.96 MPa) was significantly lower than that of the control (47.40 ± 5.03 MPa) (difference 6.47 MPa, 95 % CI 4.51 - 8.42, p < 0.001). Hardness and internal roughness of the whitening arch (VHN = 14.63 ± 2.29 N/mm2 and Ra = 1.33 ± 0.35 µm, respectively) were significantly greater than those of the control (12.22 ± 1.86 N/mm2 and 0.96 ± 0.29 µm, respectively) (differences 2.41 N/mm2, 95 % CI 1.56 - 3.25, p < 0.001 and 0.37 µm, 95 % CI 0.23 - 0.51, p < 0.001, respectively). The whitening arch showed greater tooth colour change (ΔE = 6.00 ± 3.32) than the control (ΔE = 2.50 ± 1.70) (difference = 3.50, 95 % CI 2.43 - 4.56, p < 0.001). CONCLUSIONS: Based on this short-term study, marked tooth colour change was achieved by whitening with VFRs as the whitening trays, but this changed the VFRs' biomechanical properties, including a decrease in tensile strength and an increase in hardness and internal roughness. CLINICAL SIGNIFICANCE: The application of carbamide peroxide in VFRs may compromise their mechanical properties.

Effectiveness of gold nanoparticles in prevention and treatment of oral mucositis in animal models: a systematic review.

BACKGROUND: Oral mucositis remains a significant complication during cancer therapy with no effective treatment. Gold nanoparticles offer anti-inflammatory, antioxidant properties with low toxicity. This study systematically reviews the literature assessing gold nanoparticles in the management of oral mucositis in animal models. METHODS: A literature search was undertaken using MEDLINE, Embase, PubMed, and Web of Science databases, using the format for Systematic Review Centre for Laboratory Animal Experimentation. Prior to the review, the protocol was registered in the systematic review register, PROSPERO (registration no. CRD42021272169). Outcome measures included ulceration, histopathological scores, inflammatory mediators, microbial growth, and pain. Study quality was analysed by SYRCLE risk-of-bias tool. RESULTS: Only one study met the inclusion criteria, documenting reduction in ulceration, inflammatory, and oxidative biomarkers. Exposure to AuNPs prevented inflammatory response induced by 5-fluorouracil in oral mucosa of hamsters. However, a high risk of bias necessitates further research. CONCLUSION: This review identifies a potential therapeutic strategy for prevention and management of oral mucositis. It also provides future direction for gold nanoparticle research in oral mucositis; however, there is lack of sufficient evidence to derive any conclusion. Research with standardized parameters including nanoparticle size, capping agent, surface charge, and appropriate oral mucositis animal models will establish risk-benefit balance and margin of safety for therapeutic use of gold nanoparticles for oral mucositis.

A randomized clinical trial investigating the effect of three vital tooth bleaching protocols on oral health-related quality of life.

Objectives: This study aimed to compare changes in oral health-related quality of life (OHRQoL) resulting from three vital tooth bleaching protocols. Methods: The participants (n = 105) were randomly assigned to one of three vital bleaching treatment groups: home bleaching (HB), in-office bleaching (IOB), or combined bleaching (CB). HB involved the use of custom-made trays and 10% carbamide peroxide for a 14-day treatment period. IOB utilized 37.5% hydrogen peroxide applied in three cycles. CB treatment involved the use of IOB followed by HB. Tooth colour change was evaluated using a shade guide (ΔVS) and a digital spectrophotometry device (ΔES). The Oral Health Impact Profile-14 (OHIP-14) and Oral Impact on Daily Performance-22 (OIDP-22) instruments were used to assess changes in OHRQoL at baseline, 15-days and 6-month recalls. Linear mixed models were used to estimate between- and within-group differences. Results: All bleaching protocols led to significant improvements in overall OHIP-14 scores at the 6-month recall (p ≤ 0.037). CB and IOB treatments were associated with more substantial positive impacts on overall scores, psychological discomfort, physical disability (CB only), and psychological disability (CB only) compared to HB (p ≤ 0.011). Significant enhancements in OIDP-22 scores were observed in the CB and HB groups at the 6-month recall compared to baseline (p ≤ 0.006), with evidence indicating that these improvements were greater in the CB group compared to the IOB group (p = 0.007). Conclusion: All bleaching treatments demonstrated a positive impact on OHRQoL. However, the positive impact was most consistent across domains and age groups in the CB group. The positive impact was less pronounced in older age groups.

Dentine hypersensitivity--guidelines for the management of a common oral health problem.

UNLABELLED: Dentine hypersensitivity (DHS) remains a worldwide under-reported and under-managed problem, despite making some dental treatments more stressful than necessary and having a negative impact on the patient's quality of life. This article is designed to build dental professionals' confidence and remove any confusion regarding the diagnosis, prevention and treatment of sensitive teeth caused by dentine hypersensitivity in those patients known to be at risk. There is a need for simple guidelines, which can be readily applied in general practice. However, it is also obvious that one strategy cannot suit all patients. This review describes a DHS management scheme for dental professionals that is linked to management strategies targeted at three different groups of patient. These patient groups are: 1) patients with gingival recession; 2) treatment patients with toothwear lesions; and 3) patients with periodontal disease and those receiving periodontal treatment. The authors also acknowledge the role of industry as well as dental professionals in a continuing role in educating the public on the topic of sensitive teeth. It is therefore important that educational activities and materials for both dental professionals and consumers use common terminology in order to reduce the possibility for confusion. CLINICAL RELEVANCE: This review article provides practical, evidence-based guidance on the management of dentine hypersensitivity for dental professionals covering diagnosis, prevention and treatment. Sensitivity associated with gingival recession, toothwear and periodontal disease and periodontal treatment are specifically addressed in the article.

Geriatric oral health care content and barriers to its incorporation in undergraduate nursing curricula: New Zealand survey.

INTRODUCTION: An increasingly older population demands major remodeling of our health care system. Older adults are most likely to be affected by the oral-systemic connection due to their impairment in functional capacity and reduced ability to undertake routine oral care. An economic way to improve oral health outcomes in older populations is by involving nurses and caregivers in ensuring the maintenance of oral health for older adults. This study aimed to investigate the present educational content relevant to the oral health of older adults, the oral-systemic connection, and assessment methods in New Zealand nursing education. METHODS: A cross-sectional survey was conducted among nursing educators to understand the extent of oral health care education. Quantitative descriptive data were analyzed using SPSS software and qualitative data were analyzed descriptively and presented as themes. RESULTS: The results indicated that the majority of oral health topics were already incorporated into nursing education, however most important topics such as risk factors associated with dental caries, periodontal health, and risk factors are not taught in almost 40% of the schools. The four themes identified in qualitative analyses are "no barrier", "lack of expertise", "no space for more content" and oral health content "already included". CONCLUSION: Educators reported that oral health topics are already incorporated into New Zealand undergraduate nursing curricula. However, the quantity and quality of oral health content relevant to older adults need to be improved and updated to suit the current oral health care needs of the growing older population.

Accuracy of digitally coded healing abutments: A systematic review.

The aim of this systematic review was to evaluate the in vitro accuracy of dental implant impressions taken using digitally coded healing abutments (CHAs) compared with impressions taken with conventional techniques (CI) and/or within the CHA group at varying degrees of angulations for multiple implant units. Two independent reviewers conducted a systematic electronic search in the MedLine, PubMed, Google Scholar, Cochrane Library, Web of Science, and Scopus databases. Some of the employed key terms, combined with the help of Boolean operators, were: "digitally coded healing abutments", "encode healing abutment", "dental implants", "impression accuracy", "digital impression", and "conventional impression". Publication dates ranged from January 2010 to November 2022. A total of 7 articles fulfilled the inclusion criteria: 6 studies compared the accuracy of CHA with conventional pick-up impression techniques, and one study only used CHAs at different angulations and heights to compare accuracy within the group. The results were divided into Group A (elastomeric impression of CHA) and Group B (CHA + Intraoral scanner). According to the results of this systematic review, elastomeric impression of CHA performed poorly when compared to CI for multiple implants, although an intraoral scan of CHA appears to be more accurate. Within the CHA group, the angulation and visible height of CHA play a significant role in impression accuracy. However, more studies are needed before CHA can be recommended for all non-parallel multiple implant-supported restorations.

The Effect of 10% Carbamide Peroxide Dental Bleaching on the Physical Properties of Invisalign Aligners: An In Vitro Study.

The high aesthetic demands of patients have increased their requests to align their teeth using clear aligners, including Invisalign. Patients also want to have their teeth whitened for the same purpose; the use of Invisalign as a bleaching tray at night has been reported in few studies. However, whether 10% carbamide peroxide affects the physical properties of Invisalign is unknown. Therefore, the objective of this study was to evaluate the effect of 10% carbamide peroxide on the physical properties of Invisalign when used as a bleaching tray at night. Twenty-two unused Invisalign aligners (Santa Clara, CA, USA) were used to prepare 144 specimens to test their tensile strength, hardness, surface roughness, and translucency. The specimens were divided into four groups: a testing group at baseline (TG1), a testing group after application of bleaching material at 37 °C for 2 weeks (TG2), a control group at baseline (CG1), and a control group after immersion in distilled water at 37 °C for 2 weeks (CG2). Statistical analysis was conducted using a paired t-test, Wilcoxon signed rank test, independent samples t-test, and Mann-Whitney test to compare samples in CG2 to CG1, TG2 to TG1, and TG2 to CG2. Statistical analysis showed no statistically significant difference between the groups for all physical properties, except for hardness (p-value < 0.001) and surface roughness (p-value = 0.007 and p-value < 0.001 for the internal and external surface roughness, respectively), which revealed a reduction in hardness values (from 4.43 ± 0.86 N/mm2 to 2.2 ± 0.29 N/mm2) and an increase in surface roughness (from 1.6 ± 0.32 Ra to 1.93 ± 0.28 Ra and from 0.58 ± 0.12 Ra to 0.68 ± 0.13 Ra for the internal and external surface roughness, respectively) after 2 weeks of dental bleaching. Results showed that Invisalign can be used for dental bleaching without excessive distortion or degradation of the aligner material. However, future clinical trials are required to further assess the feasibility of using Invisalign for dental bleaching.

National cross-sectional study of the sociodemographic characteristics of Aotearoa New Zealand's regulated health workforce pre-registration students: a mirror on society?

OBJECTIVES: To provide a sociodemographic profile of students enrolled in their first year of a health professional pre-registration programme offered within New Zealand (NZ) tertiary institutions. DESIGN: Observational, cross-sectional study. Data were sought from NZ tertiary education institutions for all eligible students accepted into the first 'professional' year of a health professional programme for the 5-year period 2016-2020 inclusive. VARIABLES OF INTEREST: gender, citizenship, ethnicity, rural classification, socioeconomic deprivation, school type and school socioeconomic scores. Analyses were carried out using the R statistics software. SETTING: Aotearoa NZ. PARTICIPANTS: All students (domestic and international) accepted into the first 'professional' year of a health professional programme leading to registration under the Health Practitioners Competence Assurance Act 2003. RESULTS: NZ's health workforce pre-registration students do not reflect the diverse communities they will serve in several important dimensions. There is a systematic under-representation of students who identify as Maori and Pacific, and students who come from low socioeconomic and rural backgrounds. The enrolment rate for Maori students is about 99 per 100 000 eligible population and for some Pacific ethnic groups is lower still, compared with 152 per 100 000 for NZ European students. The unadjusted rate ratio for enrolment for both Maori students and Pacific students versus 'NZ European and Other' students is approximately 0.7. CONCLUSIONS: We recommend that: (1) there should be a nationally coordinated system for collecting and reporting on the sociodemographic characteristics of the health workforce pre-registration; (2) mechanisms be developed to allow the agencies that fund tertiary education to base their funding decisions directly on the projected health workforce needs of the health system and (3) tertiary education funding decisions be based on Te Tiriti o Waitangi (the foundational constitutional agreement between the Indigenous people, Maori and the British Crown signed in 1840) and have a strong pro-equity focus.

Socio-demographic profile of medical students in Aotearoa, New Zealand (2016-2020): a nationwide cross-sectional study.

OBJECTIVE: To determine the socio-demographic profile of all students enrolled to study medicine in Aotearoa New Zealand (NZ). DESIGN AND SETTING: Observational, cross-sectional study. Data were sought from the Universities of Auckland and Otago, the two NZ tertiary education institutions providing medical education, for the period 2016-2020 inclusive. These data are a subset of the larger project 'Mirror on Society' examining all regulated health professional enrolled students in NZ. VARIABLES OF INTEREST: gender, citizenship, ethnicity, rural classification, socioeconomic deprivation, school type and school socioeconomic scores. NZ denominator population data (18-29 years) were sourced from the 2018 census. PARTICIPANTS: 2858 students were enrolled to study medicine between 2016 and 2020 inclusive. RESULTS: There were more women (59.1%) enrolled to study medicine than men (40.9%) and the majority (96.5%) were in the 18-29 years age range. Maori students (rate ratio 0.92; 95% CI 0.84 to 1.0) and Pacific students (rate ratio 0.85; 95% CI 0.73 to 0.98) had lower overall rates of enrolment. For all ethnic groups, irrespective of rural or urban origin, enrolment rates had a nearly log-linear negative relationship with increasing socioeconomic deprivation. Enrolments were lower for students from rural areas compared with those from urban areas (rate ratio 0.53; 95% CI 0.46-0.61). Overall NZ's medical students do not reflect the diverse communities they will serve, with under-representation of Maori and Pacific students and students who come from low socioeconomic and rural backgrounds. CONCLUSIONS: To meaningfully address these issues, we suggest the following policy changes: universities commit and act to Indigenise institutional ways of knowing and being; selection policies are reviewed to ensure that communities in greatest need of doctors are prioritised for enrolment into medicine (specifically, the impact of low socioeconomic status should be factored into selection decisions); and the government fund more New Zealanders to study medicine.

IMPROVDENT: improving dentures for patient benefit. A crossover randomised clinical trial comparing impression materials for complete dentures.

BACKGROUND: According to the UK Adult Dental Health Survey (2009) 15% of adults aged 65-74, 30% aged 75-84 and 47% aged >85 years are edentulous and require complete dentures. Patients' quality of life and nutrition status are affected by poor dentures. The quality of the dental impression is the most important issue for improving the fit and comfort of new dentures. There is paucity of RCT evidence for which impression material is best for complete dentures construction. This study aims to compare two impression materials for effectiveness and cost effectiveness. METHODS/DESIGN: IMPROVDENT is a double-blind crossover trial comparing the use of alginate and silicone, two commonly used denture impression materials, in terms of patient preference and cost-effectiveness. Eighty five edentulous patients will be recruited and provided with two sets of dentures, similar in all aspects except for the impression material used (alginate or silicone). Patients will try both sets of dentures for a two-week period, unadjusted, to become accustomed to the feel of the new dentures (habituation period). Patients will then wear each set of dentures for a period of 8 weeks (in random order) during which time the dentures will be adjusted for optimum comfort. Finally, patients will be given both sets of dentures for a further two weeks to wear whichever denture they prefer (confirmation period).Patients will be asked about quality of life and to rate dentures on function and comfort at the end of each trial period and asked which set they prefer at the end of the habituation period (unadjusted denture preference) and confirmation period (adjusted denture preference). A health economic evaluation will estimate incremental cost-effectiveness ratios of producing dentures from the two materials. A qualitative study will investigate the impact of dentures on behaviour and quality of life. FUNDING: IMPROVDENT is funded by NIHR RfPB (PB-PG-0408-16300). DISCUSSION: This trial aims to provide evidence on the costs and quality of dentures cast from two different commonly used impression materials; the intention is to significantly impact on the quality of denture production within NHS dentistry. TRIAL REGISTRATION: ISRCTN Register: ISRCTN01528038 UKCRN Portfolio ID: 8305.