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.

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.

Clinical and Microbiological Evaluation of a Chlorhexidine-Modified Glass Ionomer Cement (GIC-CHX) Restoration Placed Using the Atraumatic Restorative Treatment (ART) Technique.

The aims of this study were to investigate the clinical effectiveness and patient acceptability of a modified glass ionomer cement placed using the atraumatic restorative treatment (ART) technique to treat root caries, and to carry out microbiological analysis of the restored sites. Two clinically visible root surface carious lesions per participant were restored using ART. One was restored with commercial glass ionomer cement (GIC) (ChemFil® Superior, DENTSPLY, Konstonz, Germany) which acted as the control. The other carious root lesion was restored with the same GIC modified with 5% chlorhexidine digluconate (GIC-CHX; test). Patient acceptability and restoration survival rate were evaluated at baseline and after 6 months. Plaque and saliva samples around the test and control restorations were collected, and microbiological analysis for selected bacterial and fungal viability were completed at baseline, and after 1, 3, and 6 months. In total, 52 restorations were placed using GIC and GIC-CHX in 26 participants; 1 patient was lost to follow-up. After reviewing the restorations during their baseline appointments, participants indicated that they were satisfied with the appearance of the restorations (n = 25, 96%) and did not feel anxious during the procedure (n = 24, 92%). Forty-eight percent (n = 12) of the GIC-CHX restorations were continuous with the existing anatomic form as opposed to six for the GIC restorations (24%), a difference which was statistically significant (p = 0.036). There was no statistically significant reduction in the mean count of the tested microorganisms in plaque samples for either type of restorations after 1, 3, or 6 months. Restoration of carious root surfaces with GIC-CHX resulted in higher survival rates than the control GIC. ART using GIC-CHX may therefore be a viable approach for use in outreach dental services to restore root surface carious lesions where dental services are not readily available, and for older people and special needs groups.

Jet injection needle-free dental anaesthesia: Initial findings.

OBJECTIVES: We evaluated patient preference and reported levels of anxiety and discomfort of participants treated with a new needle-free electric motor-driven device vs. conventional local anaesthetic for dental extractions in a proof-of-principle study. Healing and response of gingival tissues to injection were also evaluated at 1, 3- and 7-days post-procedure. METHODS: After informed consent, eight participants who required bilateral maxillary extractions were included in the trial. The side and order of placement for the needle-free and conventional anaesthetic were randomized. The same operator delivered anaesthesia and ensured teeth were anaesthetized on both sides. Another operator, unaware of order and type of anaesthesia placed, performed the extractions. RESULTS: Participant's average discomfort scores were low for both techniques, and lower for the needle-free injection at all timepoints. Needle-free local anaesthesia was the preferred technique by most participants at most timepoints. The average volume of anaesthetic dispensed was similar between techniques. Successful anaesthesia with the needle-free device was achieved in 6 out of 8 participants. Healing of the extraction sockets and adjacent oral mucosa progressed normally for all participants, with no evidence of infection, trauma or hematoma in the injection sites of the test and conventional sides. CONCLUSIONS: The needle-free local anaesthetic technique investigated achieved sufficient anaesthesia for tooth extractions in the maxilla in 75% of the subjects. A larger clinical trial is needed to further validate the technique tested and to investigate whether needle-free local anaesthesia can be successfully applied to the provision of restorative therapy. CLINICAL SIGNIFICANCE: The results of this study can be used by clinicians treating patients who suffer from dental anxiety and needle-phobia.

An intraoral device for weight loss: initial clinical findings.

Introduction Obesity is a global epidemic, increasing the risk of many associated health issues.Aim The aim of this clinical study was to investigate the acceptability and tolerability of an intraoral device, designed to facilitate weight loss.Method Seven healthy obese participants were recruited. The device, which incorporated closed-field magnets with keepers to restrict mouth opening, was cemented to the participants' first molars. The participants were given a commercially available liquid diet for two weeks. The comfort and tolerability of the device were assessed using a quality of life questionnaire during review appointments at 1, 7 and 14 days and two weeks after device removal.Results The participants reached a mean weight loss of 6.36 (SD = 3.79) kilograms, which represents approximately 5.1% of their body weight. The participants had trouble pronouncing some words and felt tense and embarrassed 'only occasionally'. The participants 'hardly ever' reported a change in taste sensation or felt uncomfortable drinking. However, participants indicated that they occasionally had discomfort and felt that life in general was less satisfying. Qualitative analysis showed that the participants were happy with the outcome and were motivated to lose more weight.Conclusion The participants tolerated the device for a two-week period with satisfactory weight loss and were further motivated to continue their weight loss journey.

COVID-19 and dental clinical practice: Students and clinical staff perceptions of health risks and educational impact.

PURPOSE/OBJECTIVES: Due to the nature of the profession, dental healthcare workers are exposed to infectious diseases such as coronavirus disease 2019 (COVID-19), and the severity of the pandemic presents challenges to dental education institutions worldwide. This study investigated dental students and clinical staff perceptions of health risks and impacts on clinical competence of working in teaching clinics during the COVID-19 outbreak. METHODS: A 39-item survey composed of closed and open questions was sent to students and clinical staff of a prominent Australasian dental school. Questions focused on students and clinical staff perceived impact of COVID-19 on their health, clinical safety and dental education. RESULTS: The majority of staff and students perceived their health to be at risk and this increased their stress and impacted clinical performance, particularly for students. The production of aerosols and violation of cross-infection protocols by some students were the main perceived contributors to COVID-19 cross-infection in teaching clinics. Both students and staff considered the closure of teaching clinics would cause extreme impacts on students' clinical competence; however, online case-based discussions and tutorials were suggested as potential alternative teaching methods that could be adopted during that period. CONCLUSION(S): The challenges of the COVID-19 pandemic also bring opportunities for dental education development; mainly in terms of infection prevention and control improvement, preparedness to respond to future contagious diseases, and exploring the benefits of online learning in dentistry.

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.

Can the Measurement of Jaw-Opening Forces Assist in the Diagnosis of Temporomandibular Disorders?

AIMS: To investigate the effectiveness of a novel jaw-opening-force measuring device as a screening tool to aid in the diagnosis of temporomandibular disorders (TMD). METHODS: Symptomatic TMD patients (n = 58) and control TMD-free participants (n = 56) were screened by an oral medicine specialist according to the Diagnostic Criteria for TMD (DC/TMD). TMD patients were divided into three subcategories based on TMD symptoms (myofascial pain, disc displacement, and both combined). Jaw-opening forces were measured in both groups with an adjustable head device connected to a 1,000-N-load cell. Seven attempts were recorded at 10-second intervals by a data-capturing system. The geometric mean force values were obtained after discarding the first and last attempts. RESULTS: TMD-free participants had greater jaw-opening forces than TMD patients both without and with adjustments for age, sex, height, and weight (both P < .001). The geometric mean ± standard deviation values for TMD patients were 18.5 ± 1.62 N and 47.7 ± 1.53 N for TMD-free participants. Differences in jaw-opening forces among the three TMD subcategories were not statistically significant; however, patients with disc displacement (23.7 ± 1.46 N) had greater jaw forces than patients with myofascial pain (17.0 ± 1.74 N) and both myofascial pain and disc displacement (17.0 ± 1.56 N). CONCLUSION: This study demonstrated that differences in jaw-opening forces could be used as a diagnostic tool for TMD. Future studies should explore the potential of this device to measure improvement in jaw-opening forces following TMD treatment.

Simulated clinical adjustment and intra-oral polishing of two translucent, monolithic zirconia dental ceramics: An in vitro investigation of surface roughness.

OBJECTIVE: To assess the surface roughness and residual flaws in two translucent zirconia substrates following simulated clinical adjustment and intra-oral finishing/polishing. MATERIALS AND METHODS: Specimens were prepared from two translucent (5Y-ZP/8Y-ZP) and one conventional (3Y-TZP) zirconia substrates (n = 84 p/g). Arithmetic mean roughness parameter (Ra) was determined for all experimental groups at four stages (n = 21 p/g): (1) as-sintered, (2) surface grinding using a zirconia cutting diamond bur, (3) polishing using 1-step, 2-step or 4-step intra-oral polishing kits, and (4) laboratory polishing/glazing. Scanning electron microscopy (SEM) was used to evaluate residual surface flaws. Data were statistically analysed using a two-way ANOVA test, multiple and pairwise comparisons were performed using a Bonferroni post hoc test. RESULTS: Ra was significantly higher for as-sintered and ground 5Y-ZP/8Y-ZP compared to 3Y-TZP (p ≤ 0.001). Material type and polishing protocol had statistically significant effect on Ra (p < 0.001). The 4-step polishing resulted in the lowest Ra in 3Y-TZP/5Y-ZP (p ≤ 0.001). No significant differences were observed between different polishing protocols in 8Y-ZP (p≥0.655). Glazing significantly reduced Ra in all materials compared to other polishing protocols (p ≤ 0.001) except for the 4-step protocol in 3Y-TZP (p = 0.195). SEM revealed pronounced surface flaws in ground 5Y-ZP/8Y-ZP. Grinding of 3Y-TZP induced ductile material removal and thereby, minimal cohesive material loss. The 4-step polishing protocol resulted in the fewest and shallowest surface flaws in all groups. Glazing of 3Y-TZP resulted in the most homogenous surface contrary to 5Y-ZP/8Y-ZP. CONCLUSIONS: The finest surface finish was achieved using the 4-step polishing protocol in all studied materials. This protocol might be inadequate however for polishing of ground 5Y-ZP/8Y-ZP as a result of the pronounced surface damage induced by the grinding process. The glazing of 5Y-ZP/8Y-ZP might not be as predictable as for 3Y-TZP. CLINICAL SIGNIFICANCE: The higher susceptibility to surface damage, as a result of increasing dopant concentration, may render polishing of ground, translucent zirconia more complicated compared to the conventional 3Y-TZP counterparts.

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.

A randomized clinical trial investigating three vital tooth bleaching protocols and associated efficacy, effectiveness and participants' satisfaction.

OBJECTIVES: To compare tooth colour change and participant's satisfaction following: home (HB), in-office (IOB) and combined (CB) bleaching treatments. METHODS: A group of 105 participants received HB, IOB and CB treatments. HB was performed using custom-made trays and 10 % carbamide peroxide for 14 days. IOB was performed using 37.5 % hydrogen peroxide applied in 3 cycles. CB bleaching treatment involved IOB followed by HB. Tooth colour change was assessed visually (VC-ΔVC) and using a digital spectrophotometry device (ES-ΔeVS). Participant's perception of oral health, smile and straightness and whiteness of teeth were evaluated using self-reported questionnaire. Parameters/responses were evaluated/collected prior bleaching and at recalls. Linear mixed models were used to estimate between- and within-group differences. RESULTS: CB resulted in significantly higher shade difference at 15 days recall (ΔVC and ΔeVS, all p ≤ 0.046). At 6 months recall, CB group demonstrated higher ΔeVS compared to IOB (p = 0.018) but the difference was not significant between the same groups when using VC (p = 0.051). Significant colour improvement was observed among all groups at 6 months recall (all within-group p < 0.001) except older participants (≥40 years) who received HB (ΔeVS: within-group p = 0.060). Overall, self-perception of oral health and satisfaction with smile and whiteness of teeth were significantly improved in all groups (all within-group p ≤ 0.001). Satisfaction levels with straightness of teeth were significantly improved for CB and IOB overall and in younger (<40 years) participants (all within-group p ≤ 0.013). CONCLUSION: CB treatment resulted in a pronounced colour improvement when compared to both techniques used individually. All bleaching protocols resulted in significant improvement of participants' perceived oral health and satisfaction with smile and whiteness of teeth. CLINICAL SIGNIFICANCE: Accelerated whitening can be achieved using a combination of in-office and home bleaching. Patients who may accept gradual whitening of teeth can be treated effectively using a cost-effective protocol and less concentrated bleaching agents.

The teaching of removable partial dentures in dental schools in Oceania.

OBJECTIVES: To examine the current arrangements and trends in the teaching of removable partial dentures (RPDs) in dental schools in Oceania. METHODS: A validated and trialled 30-item electronic survey was sent via e-mail to 12 dental schools in Oceania that offered undergraduate dentistry. The survey explored various aspects of the teaching of RPDs in preclinical and clinical courses including: educational content and process, staff members involved, facilities and techniques utilized, clinical requirements, coursework evaluation and perceived challenges to RPD teaching. RESULTS: The response rate of the survey was 75 % (n = 9). All respondent schools taught a preclinical course in RPD design and production, with the majority (67 %) starting the clinical provision of RPD patients in Year 3. The mean duration of the course was 63 h for hands-on activities and 23 h for didactic teaching. The courses were mainly taught by senior lecturers. On average, students made four units of acrylic RPD and two cobalt-chromium RPDs during the course. All respondent schools taught prescription writing for RPD. The majority of schools (n = 8) stated that they had an adequate patient pool for students to treat. Lack of adequately trained staff for teaching and pressure on teaching time from other sources were the most commonly reported challenges. CONCLUSION: The structure and content of RPD courses in dental schools of Oceania provide an adequate level of competence on the subject, and is broadly similar to other parts of the world. Plans should be in place to maintain and improve the quality of educational programmes to keep pace with growing student numbers and the rapidly evolving profession. CLINICAL SIGNIFICANCE: With increasing numbers of patients presenting to general dental practitioners requiring complex RPDs, it is paramount that undergraduate training programs produce graduates with the competencies necessary to care for such patients to a high standard.

Direct Restorations, Endodontics, and Bleaching: Materials and Techniques Used by General Dentists of New Zealand.

BACKGROUND: To investigate the selection and use of direct restorative materials, endodontic techniques adopted, and approaches to bleaching by general dentists in New Zealand. METHODS: A questionnaire comprising 19 sections and 125 questions was distributed via mail to 351 general dentists in New Zealand who were selected, at random, from the Dental Council of New Zealand's 2016 register. RESULTS: A total of 204 questionnaires were returned, of which 188 were usable. Direct resin composite was the most commonly used material for occlusoproximal cavity restorations in premolars (93.7%) and permanent molars (85.2%). Resin-modified glass ionomer cements (34%) and resin composite materials (31.4%) were more commonly used in the restoration of deciduous molars. Home-based vital bleaching was provided by a significant number of dentists (86%), while only 18% provided practice-based bleaching. Cold lateral condensation was the most commonly used obturation technique (55.8%), and 83% of respondents reported using rubber dam for treatments. CONCLUSIONS: The findings from this study indicate that dentists in New Zealand are adapting to new materials and technologies to provide high quality care to their patients. Aesthetic treatments such as bleaching have become an integral part of general dental practice.

Vital bleaching and oral-health-related quality of life in adults: A systematic review and meta-analysis.

OBJECTIVES: To carry out a systematic review and meta-analysis of studies that investigated changes in perceived quality of life following vital tooth bleaching. METHODS: Online searches (Medline, PubMed, the Cochrane database of systemic reviews and Google scholar), bibliographic, and manual searches were carried out. Two authors independently screened the 313 articles identified from the searches and two authors extracted data, including risk of bias using the Cochrane data collection form. Random effects meta-analysis was used to estimate the pooled standardized mean difference (with 95% CI) and the 95% prediction interval. RESULTS: Only four studies met the inclusion criteria, two showing statistically significant improvement, one worsening, and one inconclusive. The pooled standardized estimate for change in quality of life after bleaching was 0.04 (95% CI -0.15, 0.24) with substantial heterogeneity (I-squared 82.1%). Within these studies, there was a pattern of improvement in aesthetic-related domains (e.g. smiling and psychological discomfort) and deterioration in function-related domains (e.g. hygiene and pain). CONCLUSIONS: Vital bleaching was not associated with improvements in overall Oral Health Related Quality of Life (OHRQoL) in these heterogeneous populations. Vital bleaching appeared to impact some domains of OHRQoL positively and some negatively, indicating the need for clinicians to treat patients receiving bleaching treatment so as to obtain the best improvement in aesthetics with minimal side effects. Clinicians should be aware of the potential impact caused by tooth sensitivity and offer proper instruction to prevent it or treatment to reduce its impact. CLINICAL SIGNIFICANCE: Bleaching treatment produces positive changes in young participants' OHRQoL in aesthetic areas such as smiling, laughing, and showing teeth without embarrassment. Tooth sensitivity, the main side-effect of vital bleaching treatment, can affect quality of life, and so oral health professionals should offer evidence-based advice to prevent and manage sensitivity.

Indirect Restorations and Fixed Prosthodontics: Materials and Techniques Used by General Dentists of New Zealand.

BACKGROUND: To investigate the selection and use of materials and techniques for core buildup, indirect restorations, and fixed prosthodontics by general dentists in New Zealand. METHODS: A questionnaire comprising 19 sections and 125 questions was distributed via mail to 351 general dentists in New Zealand who were selected from the Dental Council of New Zealand's 2016 register. RESULTS: The majority of the respondents (68.8%) reported using resin composite light-cured materials for the core buildup of vital posterior teeth. A large number of respondents (52%) did not use dentine pins, with the majority of them (25%) being recent graduates (<10 years). Fibre posts were used by 61.6% of the dentists surveyed. The majority of dentists (54.6%) reported using addition-cured silicone impression material for crown and bridge impressions. Glass-ionomer cements (37.5% of participants) and resin-modified glass-ionomer cements (35.8%) were the most common luting cements used. Direct resin composite veneers were the preferred material of choice rather than indirect restoration of anterior teeth (40.4%). CONCLUSIONS: The study showed that New Zealand dentists surveyed are using current state-of-the-art materials and techniques, with their choice of material being greatly influenced by clinical indications and patients aesthetic demands.

Dental practice in the UK in 2015/2016. Part 4: changes since 2002?

Objectives To determine, by means of anonymous self-report questionnaires, the changes in demographic profile, practising details and utilisation of clinical techniques/materials of general dental practitioners (GDPs) in the UK between 2002 and 2015. Method A wide-ranging, validated questionnaire, designed to elicit information on the practising arrangements and techniques and materials used, was distributed to UK-based GDPs in 2002, 2008 and 2015 with a request that they complete the questionnaire and return it by post in the reply-paid envelope to the corresponding author. Results Questionnaires were distributed by post to 1,000 UK-based GDPs in 2004 and 2008, with an additional 500 questionnaires being distributed at postgraduate meetings in 2015. Response rates of 70%, 66% and 78% were achieved, respectively. Of the respondents, 73% were male in 2002, while 67% and 60% were male in 2008 and 2015, respectively. In 2002, 65% were practice principals, falling to 51% in 2015. Regarding how patients paid for their dental care, 86% of respondents in 2002 treated patients within the NHS arrangements, compared with 57% and 50% in 2008 and 2015, respectively. The data collected in 2015 indicated that 55% of respondents had an intra-oral camera; while, with regard to recently introduced concepts and techniques, 80% used nickel-titanium files, 47% used zirconia-based bridgework, 25% used tricalcium silicate, and 17% used CAD/CAM restoration. Of great interest, perhaps, is the response to digital radiography/imaging, with the results indicating that, by 2015, 74% of respondents used this form of radiography. Conclusion Results from the three surveys indicated that NHS service provision has dropped to 50%. Regarding the staffing of dental practices, just over half the respondents were practice principals. The results also indicated that UK dentists continue to be innovative and forward-looking in the techniques that they employ.

The teaching of posterior composites: A survey of dental schools in Oceania.

OBJECTIVE: To investigate current teaching and operative techniques of posterior composite restorations in dental schools in Oceania (Australia, New Zealand, Fiji and Papua New Guinea). METHODS: A 24-item validated questionnaire including closed and open questions was mailed to the Heads of Department of Operative/Restorative Dentistry in 16 dental schools. Responses were compiled in Excel and analyzed. RESULTS: The response rate of this study was of 94% (n = 15). All respondent schools taught the use of posterior composites for occlusal and occluso-proximal cavities in premolars and molars. The mean percentage of preclinical teaching devoted to composites was greater than for amalgam (39% vs 29%). This proportion was anticipated to be 3:1 for posterior composite/amalgam in five years' time. Most posterior restorations placed by students are composites (average 64%, ranging from 10 to 100%), with amalgam representing 19.5% of the restorations placed (ranging from 0%-50%). Slot-type cavities were the preparation techniques most commonly taught (80%) and most schools (67%) teach the mandatory use of rubber dam for moisture control. The most common contraindication to composite placement (67% of the schools) was a history of adverse reaction to composites. The phase down of teaching and use of amalgam in Oceania is expected to occur within 8-10 years. CONCLUSIONS: Despite minimally invasive approaches becoming increasingly common worldwide, the use of amalgam is still taught in Oceania. Future studies should assess whether the clinical teaching of posterior composites is in keeping with material development and trends in mainstream dental practice.

Demographics, Practising Arrangements, and Standards: Survey among New Zealand Dentists.

BACKGROUND: To determine the demographic profile and practising arrangements of general dentists in New Zealand. METHODS: A questionnaire comprising 19 sections with 125 questions was distributed via mail to 351 general dentists in New Zealand who were selected, at random, from the Dental Council of New Zealand's 2016 register. RESULTS: Two hundred and four questionnaires were returned, of which 188 were usable giving a response rate of 53.5%. The majority of the respondents (63.5%) were male and practice principals (56.8%). Fifty-nine percent of the practices were located in city or town centres with a wide geographic distribution. Sole practitioners accounted for 24.1% of respondents, with the mean number of dentists per practice being 3.2. The majority of respondents (71.6%) attended five or more continuing professional development courses in the past year. Ninety-one percent of respondents used a computerized management system, and 95.3% used the Internet. The use of nickel-titanium endodontic files (83.9%) and digital imaging (82.2%) was the most frequently cited clinical innovations. Articaine was the most popular local anaesthetic of choice. CONCLUSIONS: Dentistry is an ever-changing profession, with evidence that NZ dentists continue to develop, learn, and embrace advancements in technologies to supply high-quality evidence-based treatment.

Mechanical properties of the human scalp in tension.

Mechanical properties of the human scalp have not been investigated to a great extent with limited information available. The purpose of this study was to provide new baseline material data for human scalp tissue of various ages, which can be applied to experimental and constitutive models, such as in the area of impact biomechanics. This study used specimens from the left and right temporal, fronto-parietal and occipital regions of the human scalp. It investigated the tensile behavior of scalp tissue using tissues harvested from unfixed, fresh cadavers. These samples were subjected to an osmotic stress analysis and upon testing, cyclic loading followed by stretching until failure in a universal testing machine. Strain evaluation was conducted using digital image correlation in a highly standardized approach. Elastic modulus, tensile strength, strain at maximum load and strain to failure were evaluated computationally. No significant differences were observed comparing the tensile strength between males and females. In contrast to that, a sex-dependent difference was found for the elastic modulus of the occipital scalp region and for the elongation properties. Additionally, regional differences within the male group, as well as an age dependent correlation for females were found in the elastic modulus and tensile strength. Scanning electron microscope analyses have shown the ultrastructural failure patterns, indicated by damaged keratin plates, as well as partially disrupted and retraced collagens at the failure site. The novel data obtained in this study could add valuable information to be used for modeling purposes, as well as provide baseline data for simulant materials and comparisons of tissue properties following head injury or forensic investigations.

Elastic behavior of brain simulants in comparison to porcine brain at different loading velocities.

Blunt force impacts to the head and the resulting internal force transmission to the brain and other cranial tissue are difficult to measure. To model blunt force impact scenarios, the compressive properties resembling tissue elasticity are of importance. Therefore, this study investigated and compared the elastic behavior of gelatin, alginate, agar/glycerol and agar/glycerol/water simulant materials to that of porcine brain in a fresh and unfixed condition. Specimens, 10 × 10 × 10mm3, were fabricated and tested at 22°C, apart from gelatin which was conditioned to 4°C prior to testing. For comparison, fresh porcine brains were sourced and prepared to the same dimensions as the simulants. Specimens underwent compression tests at crosshead displacement rates of 2.5, 10 and 16mms-1 (equivalent to strain rates of 0.25, 1 and 1.6s-1), obtaining apparent elastic moduli values at different strain rate intervals (0-0.2, 0.2-0.4 and 0.4-0.5). The results of this study indicate that overall all simulant materials had an apparent elastic moduli similar in magnitude across all strain ranges compared to brain, even though comparatively higher, especially the apparent elastic moduli values of alginate. In conclusion, while agar/glycerol/water and agar/glycerol had similar apparent elastic moduli in magnitude and the closest apparent elastic moduli in the initial strain range (E1), gelatin showed the most similar values to fresh porcine brain at the transitional (E2) and higher strain range (E3). The simulant materials and the fresh porcine brain exhibited strain rate dependent behavior, with increasing elastic moduli upon increasing loading velocities.