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    ABSTRACT: The effect of ZrO2 and TiO2 on the chemical and mechanical properties of apatite-mullite glass-ceramics was investigated after sample preparation according to the ISO (2768:2008) recommendations for dental ceramics. All materials were characterized using differential thermal analysis, X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. X-ray fluorescence spectroscopy was used to determine the concentrations of elements present in all materials produced. The chemical solubility test and the biaxial flexural strength (BFS) test were then carried out on all the samples. The best solubility value of 242 ± 61 μg/cm(2) was obtained when HG1T was heat-treated for 1 h at the glass transition temperature plus 20 °C (Tg + 20 °C) followed by 5 h at 1200 °C. The highest BFS value of 174 ± 38 MPa was achieved when HG1Z and HG1Z+T were heat-treated for 1 h at the Tg + 20 °C followed by 7 h at 1200 °C. The present study has demonstrated that the addition of TiO2 to the reference composition showed promise in both the glass and heat-treated samples. However, ZrO2 is an effective agent for developing the solubility or the mechanical properties of an apatite-mullite glass-ceramic separately but does not improve the solubility and the BFS simultaneously.
    Journal of Materials Science Materials in Medicine 03/2014; 25(3):583-594.
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    ABSTRACT: This study investigates the potential of a novel guided tissue regeneration strategy, using fully demineralized dentin infiltrated with silica and hydroxyapatite (HA) nanoparticles (NPs), to remineralize dentin collagen that is completely devoid of native hydroxyapatite. Dentin blocks were fully demineralized with 4N formic acid and subsequently infiltrated with silica and HA NPs. The remineralizing potential of infiltrated dentin was assessed following a twelve week exposure to an artificial saliva solution by means of TEM, EDS and micro-CT. Measurements were taken at baseline and repeated at regular intervals for the duration of the study to quantify the P and Ca levels, the mineral volume percentage and mineral separation of the infiltrated dentin specimens compared to sound dentin and non-infiltrated controls. Infiltration of demineralized dentin with nano-HA restored up to 55% of the P and Ca levels at baseline. A local increase in the concentration of calcium phosphate compounds over a period of twelve weeks resulted in a higher concentration in P and Ca levels within the infiltrated specimens when compared to the non-infiltrated controls. Remineralization of demineralized dentin with silica NPs by immersion in artificial saliva was the most effective strategy, restoring 20% of the P levels of sound dentin. Micro-CT data showed a 16% recovery of the mineral volume in dentin infiltrated with silica NPs and a significant decrease in the mineral separation to levels comparable to sound dentin. Demineralized dentin infiltrated with silica NPs appears to encourage heterogeneous mineralization of the dentin collagen matrix following exposure to an artificial saliva solution.
    Dental Materials 01/2014;
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    ABSTRACT: Background Regular good denture hygiene by individuals with removable partial dentures (RPDs) is an important component of oral health and in the prevention of further dental problems. These individuals should be provided with advice on the importance of denture care and be aware of this information.Aim To establish deficiencies in patient knowledge surrounding denture hygiene by RPD wearers.Methodology The study was undertaken as an audit. Data was collected from April 2012 to October 2012 via a questionnaire completed by 196 RPD wearers attending as patients at the University Dental Hospital Wales and the dental units at St David's Hospital and Cynon Valley Hospital. The audit criterion was patients with RPDs should have knowledge of denture hygiene, with the standard set at 100%.Results While 91.8% of participants stated they were provided with instructions on denture hygiene when provided with their current prosthesis, 60.2% were shown to have less than an appropriate level of denture cleanliness, with 9.2% reporting that they slept wearing their prosthesis.Conclusion The audit criterion and standard set were not achieved. A lack of knowledge surrounding denture hygiene was demonstrated among participants. As a part of the audit process the health education of RPD wearers' hygiene needs to be improved and awareness levels of the whole dental team needs to be raised. All partial dentures should receive information and regular reinforcement of key dental hygiene messages.
    British dental journal official journal of the British Dental Association: BDJ online 11/2013; 215(10):516-517.
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    ABSTRACT: Objectives Professionalism is an essential competence for dental professionals. Dental educators require both a clear definition and an understanding of the scope of professionalism in order to teach and assess it. The aim of this study was to identify concepts of professionalism in dentistry and the themes within this construct.Method Semi-structured interviews with participants purposively sampled to ensure representation of relevant viewpoints. Qualitative framework analysis was used to induct themes.Results Four themes arose from the data: (i) professionalism as a second order competence, (ii) the expression of professionalism as dependent on context, (iii) reflection as a necessary component and (iv) professionalism encompasses both tacit and overt personal aspects. These results were then incorporated into a conceptual model of dental professionalism. Conclusions Analysis of the interview data reveals that participants conceptualise professionalism as the manner in which one reflects on and reconciles different aspects of professional practice, which demonstrates acceptance of professional responsibility and accountability. It is manifested in the manner in which work is carried out. The definition and model conceptualise the construct of professionalism within dentistry that can be used to derive an educational and assessment system.
    British dental journal official journal of the British Dental Association: BDJ online 11/2013; 215(9):E18.
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    ABSTRACT: Background The behaviour of young children receiving mildly invasive dental preventive procedures in a community setting warrants more extensive research due to limitations in the literature.Objectives To document the behavioural profile of preschool children undergoing a preventive oral health intervention (fluoride varnish application) and to investigate this behaviour across children with different previous experience of the procedure, ages and initial anxiety states.Method Nurse-child interactions were video recorded and child behaviours coded and analysed using a specially developed coding scheme (SABICS). Behaviour frequency was measured and presented diagrammatically, followed by independent sample non-parametric tests to distinguish behavioural group differences.Results Three hundred and three interactions were coded out of 456 recorded application sessions. 'Nonverbal agreement' behaviour was observed most frequently compared to disruptive behaviours. Younger preschool children tended to exhibit 'interact with instrument' behaviour more frequently than older children regardless of whether they had had previous application experience. Children who showed signs of initial anxiety were likely to display more disruptive behaviours during the later stage of the procedure compared with non-anxious children.Conclusions Dental staff working with preschool children are recommended to use encouragement-centred strategies to promote nonverbal cooperative behaviours in children. In addition, procedure instruments could be considered as a tool to gain child cooperation. Evidence of an autocorrelation effect of child behaviour was found, indicating that the early presentation of child behaviour predicted the behaviour of the child at later stages.
    British dental journal official journal of the British Dental Association: BDJ online 10/2013; 215(7):340-341.
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    ABSTRACT: To validate the Dentine Hypersensitivity Experience Questionnaire in terms of responsiveness to change and to determine the minimally important difference (MID). The study was a secondary analysisof data from three randomised controlled trials with 311 participants. Three aspects of responsiveness were examined: change within individuals, differences between people who improved, stayed the same or worsened using an external referent, and change due to treatment. Responsiveness to treatments of differing efficacywas assessed in trials with negative and active controls. The measureshowed excellent internal reliability, test-retest reliability and criterion validity. The measure was highly responsive to change within individuals (Cohen's effect sizes: 0.28, 0.56, 0.86) showing decreases in the total score (i.e. improvement in OHrQoL) across all trials. The effect sizes in participants whose self-reported QoL'improved' were large (0.73 - 1.31).DHEQ detected a treatment effect in one of two negative control trials (effect size: 0.47). DHEQ scores were similar in the test and control groups in the active control trial. The minimally important differencerange wasbetween 22 and 39 points. The measure is longitudinally reliable, valid and responsive and can discriminate between treatments of different efficacy. This article is protected by copyright. All rights reserved.
    Journal Of Clinical Periodontology 10/2013;
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    ABSTRACT: To derive and evaluate a short form of the Dentine Hypersensitivity Experience Questionnaire (DHEQ). Data from three previous studies of dentine hypersensitivity (n=353) were pooled and randomly divided in half. Ten- and fifteen-item short forms were derived in the first half of the data using the item impact and regression methods. The four short forms were evaluated in the second half. The 10 and 15 item versions of the regression short form detected impacts in 37% and 61% of participants respectively, compared to 68% and 93% using the item impact method. All short forms had internal consistency (Cronbach's α) > 0.84 and test retest reliability (ICC) > 0.89. All correlated with the long form (all r > 0.93, p < 0.001) and with the effect of the mouth on everyday life (all r ≥ 0.73, p < 0.001). None of the short forms detected a treatment effect in two trials although all four showed a tendency to detect an effect in a trial where the long form had done so. The 15 item short form derived with the item impact method performed better than other short forms and appears to be sufficiently robust for use in individual patients. This article is protected by copyright. All rights reserved.
    Journal Of Clinical Periodontology 10/2013;
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    ABSTRACT: A Disintegrin And Metalloprotease (ADAM) proteins are upregulated in cancer and can interact with integrin receptors. We investigated whether such interactions may have functional significance in oral squamous cell carcinoma (OSCC). ADAM 10 expression was increased in OSCC tissue and cell lines compared to normal oral mucosa. Silencing of ADAM 10 reduced migration and invasion specifically in OSCC cells over-expressing αvβ6 integrin. This may result from ADAM 10-induced up-regulation of MMPs. We conclude ADAM 10 may influence OSCC invasion by functionally interacting with αvβ6 integrin which we have previously shown is over expressed in OSCC.
    FEBS letters 09/2013;
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    ABSTRACT: The United Kingdom's Clinical Aptitude Test (UKCAT) aims to assess candidates' "natural talent" for dentistry. The aim of this study was to determine the validity of the UKCAT for dental school applicant selection. The relationship of the UKCAT with demographic and academic variables was examined, assessing if the likelihood of being offered a place at a UK dental school was predicted by demographic factors and academic selection tools (predicted grades and existing school results). Finally, the validity of these selection tools in predicting first-year dental exam performance was assessed. Correlational and regression analyses showed that females and poorer students were more likely to have lower UKCAT scores. Gender and social class did not, however, predict first-year dental exam performance. UKCAT scores predicted the likelihood of the candidate being offered a place in the dental course; however, they did not predict exam performance during the first year of the course. Indeed, the only predictor of dental exam performance was existing school results. These findings argue against the use of the UKCAT as the sole determinant in dental applicant selection, instead highlighting the value of using existing school results.
    Journal of dental education 09/2013; 77(9):1159-70.
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    ABSTRACT: Data sourcesCochrane Oral Health Group's Trials Register, CENTRAL, Medline via OVID, EMBASE via OVID; SCISEARCH, CAplus, INSPEC, NTIS and PASCAL via STN Easy and DARE, NHS EED, HTA (all to September/ November 2012) and ClinicalTrials.gov (to July 2012). There were no restrictions on language or date of publication.Study selectionRandomised and quasi-randomised controlled trials of at least 12 months duration comparing no sealant with sealant, or different types of sealants, for preventing caries of occlusal or approximal surfaces of premolar or molar teeth in children and adolescents under 20 years of age.Data extraction and synthesisScreening of search results, data extraction and assessment of trial quality (using GRADE methods) were by two reviewers independently.ResultsThere were 34 trials of children aged five to 16 years, with 12 trials (2575 participants) comparing sealants with no sealant, 21 trials (3202 participants) comparing one sealant with another and one trial (752 participants) comparing two types of sealant with no sealant.Resin sealants compared with no sealants prevented caries in the first permanent molars of children five to 10 years old (six trials at low risk of bias with two years follow up), (odds ratio (OR) 0.12, 95% confidence interval (CI) 0.07 to 0.19). At 48 to 54 months follow-up, the caries preventive effect was maintained (OR 0.21, 95% CI 0.16 to 0.28) although there were only four trials (two were at low and two at high risk of bias).No conclusions could be drawn as to whether glass ionomer sealants compared with no sealants prevented caries at 2 year follow-up. The mean difference in DFS was -0.18, 95% CI -0.39 to 0.03.The relative effectiveness of one type of sealant compared to a different type of sealant was inconclusive as there was great variation in comparisons, outcomes, times of outcomes and background fluoride levels in the 21 studies. There was insufficient evidence for the relative superiority of glass ionomer and resin sealants (very low event rate in many of the 15 trials). There were inconsistent results for resin-modified glass ionomer sealants compared with resin sealants. No difference in caries increments were found in the two small trials of polyacid-modified resin sealants compared with resin sealants.Conclusions Sealants compared with no sealants, on the occlusal surfaces of permanent molars in children and adolescents, are effective at reducing caries up to 48 months. There is less evidence for longer term follow-up and little for the relative effectiveness of sealing in less high caries risk children. No conclusions could be drawn on the relative effectiveness of different types of sealants.
    Evidence-based dentistry 09/2013; 14(3):69-70.
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