F. M. Burke

Comparison of the efficacies of disinfectants to control microbial contamination in dental unit water systems in general dental practices across the European union

ABSTRACT Water delivered by dental unit water systems (DUWS) in general dental practices can harbor high numbers of bacteria, including opportunistic pathogens. Biofilms on tubing within DUWS provide a reservoir for microorganisms and should be controlled. This study compared disinfection products for their ability to meet the American Dental Associations guideline of <200 CFU · ml−1 for DUWS water. Alpron, BioBlue, Dentosept, Oxygenal, Sanosil, Sterilex Ultra, and Ster4Spray were tested in DUWS (n = 134) in Denmark, Germany, Greece, Ireland, The Netherlands, Spain, and the United Kingdom. Weekly water samples were tested for total viable counts (TVCs) on yeast extract agar, and, where possible, the effects of products on established biofilm (TVCs) were measured. A 4- to 5-week baseline measurement period was followed by 6 to 8 weeks of disinfection (intermittent or continuous product application). DUWS water TVCs before disinfection ranged from 0 to 5.41 log CFU · ml−1. Disinfectants achieved reductions in the median water TVC ranging from 0.69 (Ster4Spray) to 3.11 (Dentosept) log CFU · ml−1, although occasional high values (up to 4.88 log CFU · ml−1) occurred with all products. Before treatment, 64% of all baseline samples exceeded American Dental Association guidelines, compared to only 17% following commencement of treatment; where tested, biofilm TVCs were reduced to below detectable levels. The antimicrobial efficacies of products varied (e.g., 91% of water samples from DUWS treated with Dentosept or Oxygenal met American Dental Association guidelines, compared to 60% of those treated with Ster4Spray). Overall, the continuously applied products performed better than those applied intermittently. The most effective products were Dentosept and Oxygenal, although Dentosept gave the most consistent and sustained antimicrobial effect over time.

The Strengthening Mechanism of Resin Cements on Porcelain Surfaces

All-ceramic crowns bonded with resin cements have increased performance, and two theories have been proposed. Marquis (1992) suggested that the resin modified defects by crack healing, while Nathanson (1993) proposed that resin polymerization shrinkage strengthened porcelains. Both theories imply a sensitivity of strengthening to defect size. The hypothesis tested was that resin strength enhancement is independent of defect severity. We ground 200 porcelain discs to remove imperfections and indented 120 to create a large defect. Discs were tested dry, wet, and after being coated with 75–100 μm of resin cement in bi-axial flexure. Disc strength with and without indentations was increased significantly when coated with 2 resin cements. Both cements significantly increased the strength independent of defect population, and the hypothesis was accepted. It is proposed that the combination of surface pre-treatment and cement moved the fracture origin from the porcelain/cement interface to the cement surface, consistent with resin strength enhancement independent of defect severity.

Effect of pre‐heating on the viscosity and microhardness of a resin composite

The effect of pre-heating resin composite on pre-cured viscosity and post-cured surface hardness was evaluated. Groups of uncured specimens were heated to 60 degrees C and compared with control groups (24 degrees C) with respect to viscosity and surface hardness. Mean (SD) viscosities of the pre-heated specimens (n = 15) were in the range of 285 (13)-377 (11) (Pa) compared with 642 (35)-800 (23) (Pa) at ambient temperature. There was a statistically significant difference between the two groups (P < 0.001). Mean (SD) Vickers microhardness (VHN) of the pre-heated group (n = 15) was 68.6 (2.3) for the top surface and 68.7 (1.8) for the bottom surface measured at 24 h post curing (specimen thickness = 1.5 mm). The corresponding values for the room temperature group were 60.6 (1.4) and 59.0 (3.5). There was a statistically significant difference between corresponding measurements taken at the top and bottom for the pre-heated and room temperature groups (P < 0.001). There was no significant difference between top and bottom measurements within each group. Pre-heating resin composite reduces its pre-cured viscosity and enhances its subsequent surface hardness. These effects may translate as easier placement together with an increased degree of polymerization and depth-of-cure.

Attitudes of final year dental students to the use of rubber dam

AIM To investigate the attitudes of final year dental students in Wales and Ireland to the use of rubber dam. METHODS A pre-piloted questionnaire was distributed to final year dental students in Cardiff and Cork Dental Schools in January 2008. Information sought included attitudes to, and the current and anticipated use of, rubber dam for a variety of operative and endodontic treatments. RESULTS Of 93 questionnaires distributed, 87 were completed and returned (response rate = 94%; Cardiff: 89%, n = 51; Cork: 100%, n = 36). Rubber dam was routinely used by 98% of respondents (n = 85) on adult patients, but only 32% of respondents (n = 28) had used rubber dam on child patients (P < 0.05). Rubber dam was never used by 75% of respondents (n = 65) when placing posterior amalgam restorations, and by 21% of respondents (n = 18) when placing anterior composite restorations. Rubber dam was used by 98% of the respondents (n = 85) when performing root canal treatments. Sixty-two per cent of respondents (n = 54) believed their use of rubber dam would decrease once leaving the dental school. CONCLUSION Whilst dental students believe that rubber dam is relevant to clinical dentistry, there are negative perceptions associated with its use amongst dental students. More than half of those questioned predicted their use of rubber dam would decrease once in independent practice. Greater emphasis should be placed on the advantages of using rubber dam in clinical dentistry whilst at dental school.

Risk indicators associated with root caries in independently living older adults

OBJECTIVE To determine the risk indicators associated with root caries experience in a cohort of independently living older adults in Ireland. METHODS The data reported in the present study were obtained from a prospective longitudinal study conducted in a cohort of independently living older adults (n=334). Each subject underwent an oral examination, performed by a single calibrated examiner, to determine the root caries index and other clinical variables. Questionnaires were used to collect data on oral hygiene habits, diet, smoking and alcohol habits and education level. A regression analysis with the outcome variable of root caries experience (no/yes) was conducted. RESULTS A total of 334 older dentate adults with a mean age of 69.1 years were examined. 53.3% had at least one filled or decayed root surface. The median root caries index was 3.13 (IQR 0.00, 13.92). The results from the multivariate regression analysis indicated that individuals with poor plaque control (OR 9.59, 95% CI 3.84-24.00), xerostomia (OR 18.49, 95% CI 2.00-172.80), two or more teeth with coronal decay (OR 4.50, 95% CI 2.02-10.02) and 37 or more exposed root surfaces (OR 5.48, 95% CI 2.49-12.01) were more likely to have been affected by root caries. CONCLUSIONS The prevalence of root caries was high in this cohort. This study suggests a correlation between root caries and the variables poor plaque control, xerostomia, coronal decay (≥2 teeth affected) and exposed root surfaces (≥37). The significance of these risk indicators and the resulting prediction model should be further evaluated in a prospective study of root caries incidence. CLINICAL SIGNIFICANCE Identification of risk indicators for root caries in independently living older adults would facilitate dental practitioners to identify those who would benefit most from interventions aimed at prevention.

Failure rates of class V restorations in the management of root caries in adults – a systematic review

OBJECTIVE The aim of this systematic review was to compare cumulative failure rates of different restorative materials in carious class V lesions on the root surfaces of adult patients. BACKGROUND The prevalence of root caries is set to increase in the coming years as a result of ageing of the population and a concomitant reduction in levels of edentulousness. Evidence is needed to assist practitioners to select the most appropriate restorative material for use in these lesions. METHODS A search of the literature was undertaken using the electronic databases of PubMed, Embase, CENTRAL and OpenSIGLE using keywords relevant to the search question. Two review authors conducted the electronic search independently, and any conflict was resolved by discussion. The references quoted in the full text articles extracted were hand searched for any further eligible studies. RESULTS Sixty non-duplicate citations were screened. Following review of the titles, abstracts, texts and application of the pre-determined inclusion/exclusion criteria, five studies remained. CONCLUSION There is a need for more research in this area as many of the studies identified in this systematic review treated post-radiation, xerostomic patients which are not typical of the general population. Increased adherence to CONSORT guidelines for reporting is also advised to facilitate future systematic review and meta-analysis in this area.

Attitudes of final-year dental students to bleaching of vital and non-vital teeth in Cardiff, Cork, and Malmö

The aim of this study was to determine attitudes of final-year dental students in Cardiff, Cork and Malmö towards tooth whitening. Following receipt of ethical approval, pre-piloted questionnaires were distributed to final-year dental students in Cork, Cardiff, and Malmö as close as possible to graduation. The questionnaire sought information relating to various opinions and attitudes towards the use of bleaching techniques including safety of bleaching, confidence in the provision of bleaching, recommendations to patients, teaching received, awareness of restrictions on the use of bleaching products and management of simulated clinical scenarios. Eighty three per cent (n = 116) of questionnaires were returned. Cork dental students had the most didactic teaching (2-h vital, 1-h non-vital bleaching) compared to Cardiff or Malmö students (0 h each). More Cork students regarded bleaching as safe (76%, n = 28) than Cardiff (70%, n = 32) or Malmö (36%, n = 12) students. More than 50% of Cork students feel they know enough about bleaching to provide it in practice, significantly more than Cardiff (< 25%) or Malmö (< 25%) students. The majority of students would provide vital bleaching after qualification (100% (n = 37) Cork; 82% (n = 27) Malmö; 76% (n = 35) Cardiff). In simulated clinical scenarios, more Cork students would propose bleaching treatments (89%n = 33) than Malmö (64%n = 21) or Cardiff (48%n= 22) students. Variations exist in the attitudes and approaches of three European dental schools towards bleaching. Dental students need to be best prepared to meet the needs of their future patients.

Fluoridation and tooth wear in Irish adults

The aim of this study was to determine the prevalence of tooth wear in adults in Ireland and its relationship with water fluoridation. The National Survey of Adult Oral Health was conducted in 2000/2001. Tooth wear was determined using a partial mouth examination assessing the upper and lower anterior teeth. A total of 2456 subjects were examined. In this survey, increasing levels and severity of tooth wear were associated with ageing. Men were more affected by tooth wear and were more likely to be affected by severe tooth wear than women. It was found that age, and gender were significant predictors of tooth wear (P < 0.01). Overall, there was no significant relationship between fluoridation and tooth wear in this study.

Endodontic access cavity simulation in ceramic dental crowns

OBJECTIVES It is proposed that a non-uniform rational B-spline (NURBS) based solid geometric model of a ceramic crown would be a flexible and quick approach to virtually simulate root canal access cavities. The computation of strain components orthogonal to surface flaws generated during the drilling would be an appropriate way of comparing different access cavity configurations. METHODS A μCT scan is used to develop a full 3D NURBS geometric solid model of a ceramic crown. Three different access cavity configurations are created virtually in the geometric model and there are then imported into proprietary finite element software. A linear analysis of the each crown is carried out under appropriate in vivo loading and the results are post-processed to carry out a quantitative comparison of the three configurations RESULTS The geometric model is shown to be a flexible and quick way of simulation access cavities. Preliminary indications are that post processed strain results from the finite element analysis are good comparators of competing access cavity configurations. SIGNIFICANCE The generation of geometric solid models of dental crowns from μCT scans is a flexible and efficient methodology to simulate a number of access cavity configurations. Furthermore, advanced post-processing of the primary finite element analysis results is worthwhile as preliminary results indicate that improved quantitative comparisons between different access cavity configurations are possible.

Presentation of lacrimo-auriculo-dento-digital (LADD) syndrome in a young female patient

BACKGROUND: Lacrimo-auriculo-dento-digital (LADD) syndrome (OMIM #149730) is an autosomal-dominant congenital disorder that can be caused by heterozygous mutations in the tyrosine kinase domains of the genes encoding fibroblast growth factor receptors 2 (FGFR2) and 3 (FGFR3), and has been found in association with a mutation in the FGF10 gene, which encodes an Fgfr ligand. Clinical signs vary, but the condition is characterised by involvement of the lacrimal and salivary systems, cup-shaped ears, hearing loss and dental abnormalities. Additional features may include involvement of the hands and feet with other body systems particularly the kidneys. CASE REPORT: Previous literature on the subject has been reviewed and this case is the first presentation of LADD syndrome in the Republic of Ireland, as a sporadic case in a 12-year-old girl who exhibited a range of dental and digital anomalies. TREATMENT: Her general medical practitioner managed her medical care whilst her oral care necessitated a multidisciplinary approach involving restorative and orthodontic elements. FOLLOWUP: The initial restorative phase of treatment has successfully improved the appearance of the patient ’s anterior teeth using direct resin composite build-ups.