• Base-metal dental casting alloy biocompatibility assessment using a human-derived three-dimensional oral mucosal model.

      McGinley, E L; Moran, G P; Fleming, G J P; Materials Science Unit, Division of Oral Biosciences, Dublin Dental University Hospital, Trinity College Dublin, Dublin, Ireland. emmalouise.mcginley@dental.tcd.ie (2012-01)
      Nickel-chromium (Ni-Cr) alloys used in fixed prosthodontics have been associated with type IV Ni-induced hypersensitivity. We hypothesised that the full-thickness human-derived oral mucosa model employed for biocompatibility testing of base-metal dental alloys would provide insights into the mechanisms of Ni-induced toxicity. Primary oral keratinocytes and gingival fibroblasts were seeded onto Alloderm™ and maintained until full thickness was achieved prior to Ni-Cr and cobalt-chromium (Co-Cr) alloy disc exposure (2-72 h). Biocompatibility assessment involved histological analyses with cell viability measurements, oxidative stress responses, inflammatory cytokine expression and cellular toxicity analyses. Inductively coupled plasma mass spectrometry analysis determined elemental ion release levels. We detected adverse morphology with significant reductions in cell viability, significant increases in oxidative stress, inflammatory cytokine expression and cellular toxicity for the Ni-Cr alloy-treated oral mucosal models compared with untreated oral mucosal models, and adverse effects were increased for the Ni-Cr alloy that leached the most Ni. Co-Cr demonstrated significantly enhanced biocompatibility compared with Ni-Cr alloy-treated oral mucosal models. The human-derived full-thickness oral mucosal model discriminated between dental alloys and provided insights into the mechanisms of Ni-induced toxicity, highlighting potential clinical relevance.
    • Basic guide to dental materials

      Scheller-Sheridan, C. (Wiley-Blackwell, 2010)
    • Beckwith-Wiedemann syndrome: dental management.

      Garvey, M T; Daly, D; McNamara, T; Department of Child Dental Health, Dublin Dental Hospital, Ireland. (1997-06)
      Beckwith-Wiedemann syndrome (BWS) comprises multiple congenital anomalies with a risk of childhood tumours. Macroglossia is the most common manifestation. Two cases are presented to illustrate the importance of early referral and the role of preventive dentistry.
    • Biofilm problems in dental unit water systems and its practical control.

      Coleman, D C; O'Donnell, M J; Shore, A C; Russell, R J; Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental School & Hospital, University of Dublin, Trinity College Dublin, Lincoln Place, Dublin 2, Ireland. david.coleman@dental.tcd.ie (2009-05)
      Dental chair units (DCUs) contain integrated systems that provide the instruments and services for a wide range of dental procedures. DCUs use water to cool and irrigate DCU-supplied instruments and tooth surfaces during dental treatment. Water is supplied to these instruments by a network of interconnected narrow-bore (2-3 mm) plastic tubes called dental unit waterlines (DUWLs). Many studies over the last 40 years demonstrated that DUWL output water is often contaminated with high densities of micro-organisms, predominantly Gram-negative aerobic heterotropic environmental bacteria, including Legionella and Pseudomonas species. Untreated DUWLs host biofilms that permit micro-organisms to multiply and disperse through the water network and which are aerosolized by DCU instrument use, thus exposing patients and staff to these micro-organisms, to fragments of biofilm and bacterial endotoxins. This review concentrates on how practical developments and innovations in specific areas can contribute to effective DUWL biofilm control. These include the use of effective DUWL treatment agents, improvements to DCU supply water quality, DCU design changes, development of automated DUWL treatment procedures that are effective at controlling biofilm in the long-term and require minimal human intervention, are safe for patients and staff, and which do not cause deterioration of DCU components following prolonged use.
    • Can a soda-lime glass be used to demonstrate how patterns of strength dependence are influenced by pre-cementation and resin-cementation variables?

      Hooi, Paul; Addison, Owen; Fleming, Garry J P; Materials Science Unit, Dublin Dental University Hospital, Lincoln Place, Trinity College Dublin, Ireland. paul.hooi@dental.tcd.ie (Journal of dentistry, 2013-01)
      To determine how the variability in biaxial flexure strength of a soda-lime glass analogue for a PLV and DBC material was influenced by precementation operative variables and following resin-cement coating.
    • Can evaluation of a dental procedure at the outset of learning predict later performance at the preclinical level? A pilot study.

      Polyzois, Ioannis; Claffey, Noel; McDonald, Albhe; Hussey, David; Quinn, Frank; Department of Restorative Dentistry and Periodontology, Dublin Dental School and Hospital, Dublin, Ireland. ioannis.polyzois@dental.tcd.ie (2011-05)
      The purpose of this study was to examine the effectiveness of conventional pre-clinical training in dentistry and to determine if evaluation of a dental procedure at the beginning of dental training can be a predictor for future performance. A group of second year dental students with no previous experience in operative dentistry were asked to prepare a conventional class I cavity on a lower first molar typodont. Their first preparation was carried out after an introductory lecture and a demonstration and their second at the end of conventional training. The prepared typodonts were coded and blindly scored for the traditional assessment criteria of outline form, retention form, smoothness, cavity depth and cavity margin angulation. Once the codes were broken, a paired t-test was used to compare the difference between the means of before and after scores (P<0.0001) and a Pearson's linear correlation to test the association (r=0.4). From the results of this study, we could conclude that conventional preclinical training results in a significant improvement in the manual skills of the dental students and that the dental procedure used had only a limited predictive value for later performance at the preclinical level.
    • Can poly(acrylic) acid molecular weight mixtures improve the compressive fracture strength and elastic modulus of a glass-ionomer restorative?

      Dowling, Adam H; Fleming, Garry J P; Materials Science Unit, Division of Oral Biosciences, Dublin Dental University Hospital, Trinity College Dublin, Dublin, Ireland. adam.dowling@dental.tcd.ie (2011-11)
      To optimize the compressive fracture strength (σ) and elastic modulus (E) of a glass-ionomer (GI) restorative using poly(acrylic) acid (PAA) weight average molecular weight (M(w)) mixtures.
    • Candida albicans versus Candida dubliniensis: Why Is C. albicans More Pathogenic?

      Moran, Gary P; Coleman, David C; Sullivan, Derek J; Division of Oral Biosciences, Dublin Dental University Hospital, Trinity College Dublin, Dublin 2, Ireland. (International journal of microbiology, 2012)
      Candida albicans and Candida dubliniensis are highly related pathogenic yeast species. However, C. albicans is far more prevalent in human infection and has been shown to be more pathogenic in a wide range of infection models. Comparison of the genomes of the two species has revealed that they are very similar although there are some significant differences, largely due to the expansion of virulence-related gene families (e.g., ALS and SAP) in C. albicans, and increased levels of pseudogenisation in C. dubliniensis. Comparative global gene expression analyses have also been used to investigate differences in the ability of the two species to tolerate environmental stress and to produce hyphae, two traits that are likely to play a role in the lower virulence of C. dubliniensis. Taken together, these data suggest that C. dubliniensis is in the process of undergoing reductive evolution and may have become adapted for growth in a specialized anatomic niche.
    • The Candida albicans-specific gene EED1 encodes a key regulator of hyphal extension.

      Martin, Ronny; Moran, Gary P; Jacobsen, Ilse D; Heyken, Antje; Domey, Jenny; Sullivan, Derek J; Kurzai, Oliver; Hube, Bernhard; Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knoell Institute, Jena, Germany. (2011-04)
      The extension of germ tubes into elongated hyphae by Candida albicans is essential for damage of host cells. The C. albicans-specific gene EED1 plays a crucial role in this extension and maintenance of filamentous growth. eed1Δ cells failed to extend germ tubes into long filaments and switched back to yeast growth after 3 h of incubation during growth on plastic surfaces. Expression of EED1 is regulated by the transcription factor Efg1 and ectopic overexpression of EED1 restored filamentation in efg1Δ. Transcriptional profiling of eed1Δ during infection of oral tissue revealed down-regulation of hyphal associated genes including UME6, encoding another key transcriptional factor. Ectopic overexpression of EED1 or UME6 rescued filamentation and damage potential in eed1Δ. Transcriptional profiling during overexpression of UME6 identified subsets of genes regulated by Eed1 or Ume6. These data suggest that Eed1 and Ume6 act in a pathway regulating maintenance of hyphal growth thereby repressing hyphal-to-yeast transition and permitting dissemination of C. albicans within epithelial tissues.
    • Capping in a mature tooth

      Duncan, HF (Oxford, Wiley-Blackwell, 2011)
    • Case report: management of broken dental needles in practice

      Rahman, Naomi; Clarke, Mary; Stassen, Leo FA (Irish Dental Assocation (IDA), 2013-10)
      It is estimated that 60,000 cartridges of local anaesthetic are used weekly in the USA for dental anaesthesia by infiltration or block injections.1 The complication of needle breakage after an inferior alveolar nerve block is relatively rare in dental practice.2 One of the first ever case series on dental needle breakage was published in 1928 by Blum, who reported 65 broken needles over a tenyear period.3 The routine use of single-use, disposable stainless steel needles made from stronger alloys has decreased this complication.4 Today, needle breakage during local anaesthesia may be attributed to a faulty needle, an incorrect anaesthetic injection technique or sudden movement by the patient in a direction opposite to the needle.5 It is important to caution the patient against sudden movement during administration of the injection. The needle should not be redirected against tissue resistance while it is embedded in tissue, as this can cause breakage to occur.6
    • Case report: Management of severe posterior open bite due to primary failure of eruption.

      Mc Cafferty, J; Al Awadi, E; O'Connell, A C; Division of Public and Child Dental Health, Dublin Dental School and Hospital, Dublin 2. Ireland. mccaffej@tcd.dental.ie (2010-06)
      In this unique case, a profound unilateral posterior open bite occurred due to primary failure of eruption of the maxillary and mandibular teeth on the affected side. Orthodontic therapy was used to modify the position of the permanent canines and premolars to reduce the posterior open bite.
    • Case report: pre-eruptive intra-coronal radiolucencies revisited.

      Counihan, K P; O'Connell, A C; Department of Paediatric Dentistry, Leeds Dental Institute, Leeds, UK. katepcounihan@gmail.com (European archives of paediatric dentistry : official journal of the European Academy of Paediatric Dentistry, 2012-08)
      Pre-eruptive intra-coronal radiolucency (PEIR) describes a radiolucent lesion located in the coronal dentine, just beneath the enamel-dentine junction of unerupted teeth. The prevalence of this lesion varies depending on the type and quality of radiographic exposure and age of patients used for assessment. The aetiology of pre-eruptive intra-coronal radiolucent lesions is not fully understood, but published clinical and histological evidence suggest that these lesions are resorptive in nature. Issues around the diagnosis, treatment planning and clinical management of this lesion are explored using previously unreported cases.
    • Case report: sublingual epidermoid cyst in an elderly patient

      Anderson, Stephen; Stassen, Leo FA (Irish Dental Association, 2014-05)
      A 77-year-old female was referred by her general dental practitioner (GDP) to the accident and emergency (A and E) department of Dublin Dental University Hospital (DDUH). The patient’s dentist had noted an incidental finding of a swelling ‘the size of an apple’ in the patient’s floor of mouth. The patient reported that the swelling had been present and unchanged for around three years. The patient presented with no dyspnoea, dysphagia, or pain, and seemed unconcerned by the swelling. The patient’s family did report a slight change in speech over recent years – she had developed a slight lisp. There was no history of previous trauma or surgery to the region.
    • Cautionary note: a possible association between oral squamous cell carcinoma and tumor necrosis factor antagonists; need for oral screening.

      Rahman, N; Healy, C; Flint, Stephen R; Stassen, L F A; Department of Oral and Maxillofacial Surgery and Oral Medicine, Dublin Dental School and Hospital, Trinity College Dublin, Ireland. naomirahman@hotmail.com (2010-06)
    • Cdr2p contributes to fluconazole resistance in Candida dubliniensis clinical isolates.

      Borecká, Silvia; Pinjon, Emmanuelle; Sullivan, Derek J; Kuchler, Karl; Blaško, Jaroslav; Kulková, Naďa; Bujdáková, Helena; Comenius University in Bratislava, Department of Microbiology and Virology, Mlynská dolina, Bratislava, Slovak Republic. (2011-05)
      The development of resistance to azole antifungals used in the treatment of fungal infections can be a serious medical problem. Here, we investigate the molecular mechanisms associated with reduced susceptibility to fluconazole in clinical isolates of Candida dubliniensis , showing evidence of the trailing growth phenomenon. The changes in membrane sterol composition were studied in the presence of subinhibitory fluconazole concentrations. Despite lanosterol and eburicol accumulating as the most prevalent sterols after fluconazole treatment, these ergosterol precursors still support growth of Candida isolates. The overexpression of ABC transporters was demonstrated by immunoblotting employing specific antibodies against Cdr1p and Cdr2p. The presence of a full-length 170 kDa protein Cdr1p was detected in two isolates, while a truncated form of Cdr1p with the molecular mass of 85 kDa was observed in isolate 966/3(2). Notably, Cdr2p was detected in this isolate, and the expression of this transporter was modulated by subinhibitory concentrations of fluconazole. These results suggest that C. dubliniensis can display the trailing growth phenomenon, and such isolates express similar molecular mechanisms like that of fluconazole-resistant isolates and can therefore be associated with recurrent infections.
    • Cellular and molecular biomechanics

      Campbell, V.A; O'Connell, B (2010)
    • A centralised, automated dental hospital water quality and biofilm management system using neutral Ecasol maintains dental unit waterline output at better than potable quality: a 2-year longitudinal study.

      O'Donnell, M J; Boyle, M; Swan, J; Russell, R J; Coleman, D C; Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental School & Hospital, University of Dublin, Trinity College Dublin, Lincoln Place, Dublin 2, Ireland. (2009-10)
      This centralised and automated water treatment and biofilm management system consistently maintains DUWL output water at better than potable quality simultaneously in a large number of DCUs over the long-term.
    • Characterisation of MRSA from Malta and the description of a Maltese epidemic MRSA strain.

      Scicluna, E A; Shore, A C; Thürmer, A; Ehricht, R; Slickers, P; Borg, M A; Coleman, D C; Monecke, S; Infection Control Unit, Mater Dei Hospital, Msida, Malta. (2010-02)
      Malta has one of the highest prevalence rates of methicillin-resistant Staphylococcus aureus (MRSA) in Europe. However, only limited typing data are currently available. In order to address this situation, 45 MRSA isolates from the Mater Dei Hospital in Msida, Malta, were characterised using DNA microarrays. The most common strain was ST22-MRSA-IV (UK-EMRSA-15, 30 isolates). Sporadic strains included ST36-MRSA-II (UK-EMRSA-16, two isolates), PVL-positive ST80-MRSA-IV (European Clone, one isolate), ST228-MRSA-I (Italian Clone/South German Epidemic Strain, one isolate) and ST239-MRSA-III (Vienna/Hungarian/Brazilian Epidemic Strain, one isolate). Ten MRSA isolates belonged to a clonal complex (CC) 5/ST149, spa type t002 strain. This strain harboured an SCCmec IV element (mecA, delta mecR, ugpQ, dcs, ccrA2 and ccrB2), as well as novel alleles of ccrA/B and the fusidic acid resistance element Q6GD50 (previously described in the sequenced strain MSSA476, BX571857.1:SAS0043). It also carried the gene for enterotoxin A (sea) and the egc enterotoxin locus, as well as (in nine out of ten isolates) genes encoding the toxic shock syndrome toxin (tst1) and enterotoxins C and L (sec, sel). While the presence of the other MRSA strains suggests foreign importation due to travel between Malta and other European countries, the CC5/t002 strain appears, so far, to be restricted to Malta.