Oral Biosciences

This division is responsible for Laboratory based research in Oral Microbiology and Material Science

(Head of Division – Professor David Coleman)

Division of Oral Biosciences

This division consists of two units and undertakes basic, clinical and applied research on Oral Microbiology and Material Science. The division provides diagnostic microbiology services for the Dublin Dental Hospital clinics and outside dental clinics staffed by Dental Hospital personnel and plays a major role in the provision of teaching to undergraduate and postgraduate students. (Head of Division – Professor David Coleman).

Staff Members of Division

David Coleman, Garry Fleming, Gary Moran,  Mary O’Donnell, Anna Shore, Derek Sullivan.

Microbiology Research Unit

Research:

The Microbiology Research Group conducts basic, applied and translational research in four key research fields:

• Epidemiology, population biology, genomics, drug resistance mechanisms and virulence mechanisms of the fungal species responsible for oral candidosis, especially Candida albicans and Candida dubliniensis. The C. dubliniensis yeast species was first identified and named by our group in 1995 and the Unit acts as an international centre of excellence for research into this novel pathogen.
• Management and control of microbial biofilm contamination of dental chair unit waterlines and suction systems and large water distribution systems in healthcare facilities. This research involves close collaboration with Planmeca Oy, a Helsinki-based dental chair unit manufacturing company. Mixed-species bacterial biofilm formation in dental chair unit components is a universal problem and much of our research in this field has been translated into improved dental chair unit designs, with enhanced features for more effective control and bio-decontamination of microbial biofilm. Other research with the Irish safe water technology company Trustwater (Clonmel, County Tipperary) has resulted in the development of large-scale fully automated systems for maintaining the quality of water in healthcare facilities at better than potable quality standards.
• The molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) from Irish hospital and community sources. Much of this work focuses on the application of high-throughput systems, including DNA microarrays, for screening clinical isolates in order to trace infection routes and detect the emergence of new MRSA derivatives. This research is being undertaken in collaboration with the National MRSA Reference Laboratory at St. James’s Hospital, Dublin and research partners at Beaumont Hospital, St. James’s Hospital and in Germany and the USA.
• The development of in vitro models to study mixed species biofilms of Porphyromonas gingivalis and Fusobacterium nucleatum, two of the most significant bacterial pathogens involved in human periodontal disease. The models are being assessed both as a tool for translational research in assessing novel antimicrobial strategies to eradicate periodontal biofilm and as a tool to study bacterial interactions within biofilms.

Diagnostics:

Microbiology Unit personnel also provide a clinical diagnostic service for oral fungal infections. This service identifies the causative agents of fungal infections of the oral cavity and where appropriate susceptibility levels to antifungal agents are determined to facilitate effective drug treatment. Microbiology Unit staff are also responsible for ensuring good microbiological quality of dental chair unit output water and for advising on Legionella bacteria controls for the  hospital’s water distribution system.

Infection Prevention and Control:

Microbiology Unit personnel have been engaged in the development of National best practice guidelines for the control of Legionellosis in Ireland with the Health Protection Surveillance Centre and in the development of the Code of Practice for the decontamination of reusable invasive medical devices with the Health Services Executive. Microbiology Unit personnel provide expert advice and practical assistance in the development and implementation of hospital infection prevention and control policies in-line with best practice and national and international guidelines and legislation.

Education:

Microbiology Unit personnel play a major role in curriculum development and in teaching basic and clinical sciences to:

• Undergraduate dental students
• Student dental nurses and student hygienists
• Postgraduate dentists undertaking taught doctorate degrees
• Supervising postgraduate students undertaking M.Sc. and Ph.D. degrees by research
• Supervising postgraduate student D. Dent. Ch. research projects

Materials Science Unit

Research:

The Dental Materials Science Research Unit undertakes research into a variety of dental materials routinely employed in clinical practice.

The projects currently under investigation include:

• Research into developing an ideal posterior filling material to replace dental amalgam. Recent research investigations have included gallium-based alloys and conventional methacrylate resin and oxirane resin based composites (RBCs). More recently research has focused on RBC research in particular nano-composites and low shrink organically modified ceramics as well as reinforced glass-ionomer restoratives as possible aesthetic alternatives to dental amalgams.

• The unit also undertakes research on the performance of all-ceramic restorations including porcelain laminate veneers, crowns and bridges. The unit has employed an in-vitro mechanical test to examine the clinical failure mode and fracture origin of dentine bonded crowns and the connector area of fixed partial dentures produced by different laboratory and machined fabrication processes. Recent research has focused on a novel profilometric technique to determine stressing patterns throughout the thickness of a dentine bonded crown material induced by pre-cementation and cementation operative techniques. The deflection test has proved to be a reliable method that enabled quantification of the stresses induced in dentine bonded crown materials and offers a further complimentary tool to the ceramicists’ armoury as a non-destructive test.

• Research within the unit also include the performance of dental cements when employed in conjunction with dental ceramics and include investigations into the corrosive potential of acid-base cements and the apparent strengthening mechanism of resin cements on controlled porcelain surfaces.

• Investigations into the potential toxicity effects of Nickel containing dental alloys routinely used in metal-ceramic crowns are also ongoing in the unit. Biocompatibility studies employed include the assessment of cell density, cell morphology, and cell viability. Cellular proliferation analysis includes using an XTT metabolic assay techniques, cellular toxicity levels with LDH assay techniques and metal ion release by ICP-MS techniques are regularly performed. Immunological cytokine profiles with a sandwich ELISA method specific for inflammatory molecules IL-1α, IL-8, PGE2 and TNF-α are also employed for biocompatibility studies.

Education:

Materials Science unit personnel are involved in teaching materials science to:

• Dental, hygiene and therapy, dental technology and dental nursing students
• Supervising postgraduate students undertaking M.Sc. and Ph.D. degrees by
• Research
• Supervising postgraduate student D. Dent. Ch. research projects

Staff Profile: Mary O’Donnell

Title: Senior Experimental Officer in Microbiology and Infection Prevention and Control

Qualifications: R.D.N., FAETC., M.Sc., Ph.D.

Contact details:

Tel: +353 (01) 612 7269

Email: mary.odonnell@dental.tcd.ie

Administrative responsibilities:

• Manager of Oral Biosciences Laboratory
• Responsible for infection prevention and control and biological and chemical risk management

Teaching:

• Microbiology and infection prevention and control
• Biological safety

Research Interests:

Control of microbial biofilm contamination in dental chair unit waterlines and suction systems

My main research interest focuses on the control of biofilms in dental chairs and associated water distribution networks. Dental chair units are universally prone to contamination with high densities of microorganisms, especially bacterial species. For the last 10 years I have been engaged in collaborative research with the Finnish dental chair manufacturer Planmeca (Helsinki, Finland) to develop practical solutions to dental unit biofilm. This resulted in the development of several novel dental chair units with integrated semi-automated or automated biofilm control systems. More recently, my research has focused on the application of the electrochemically-activated solution Ecasol for biofilm control. This research resulted in the development of fully automated, self-cleaning, large-scale systems capable of consistently maintaining dental unit supply and output water at better than drinking water quality simultaneously in hundreds of dental units. This work was undertaken in collaboration with the Irish safe water technology company Trustwater (Clonmel, County Tipperary). Current research includes the miniaturization of the large-scale systems for use with individual dental units.

Representative recent publications:

1. Coleman DC, O’Donnell MJ, Boyle M, Russell R. (2010). Microbial biofilm control within the dental clinic: reducing multiple risks. Journal of Infection Prevention. 192-11:198.

2. Boyle MA, O’Donnell MJ, Russell RJ, Coleman DC. (2010). Lack of cytotoxicity by Trustwater Ecasol™ used to maintain good quality dental unit waterline output water in keratinocyte monolayer and reconstituted human oral epithelial tissue models. Journal of Dentistry. 38:930-940.

3. Coleman DC, O’Donnell MJ, Shore AC, Russell RJ. (2009). Biofilm problems in dental unit water systems and its practical control. (2009). Journal of Applied Microbiology. 106:1424-1437

4. Donnell MJ, Boyle M, Swan J, Russell RJ, Coleman DC. (2009). 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. Journal of Dentistry. 37:748-762.

5. Coleman DC, O’Donnell MJ, Shore AC, Swan J, Russell RJ. (2007). The role of manufacturers in reducing biofilms in dental chair waterlines. Journal of Dentistry. 35:701-711.

6. O’Donnell MJ, Shore AC, Russell RJ, Coleman DC. (2007). Optimisation of the long-term efficacy of dental chair waterline disinfection by the identification and rectification of factors associated with waterline disinfection failure. Journal of Dentistry. 35:438-451.

Full CV

Staff Profile: Anna Shore

Title:  Lecturer in Applied and Translational Microbiology

Qualifications: B.Sc. (Hons.), Ph.D.

Contact details:

Tel: +353 (01) 6127350

Email: anna.shore@dental.tcd.ie

Teaching:

• Microbiology and infection control and prevention
• Postgraduate (Ph.D.) research student supervision

Research Interests:

Molecular characterisation and epidemiological typing of staphylococci, including methicillin-resistantStaphylococcus aureus (MRSA), methicillin-susceptible S. aureus (MSSA) and coagulase-negative staphylococci (CoNS).

My main research interest involves the molecular characterisation of MRSA, MSSA and CoNS from hospitals, communities and animals in Ireland. Since the 1970s MRSA has been a major cause of hospital-acquired infections worldwide and it contributes significantly to patient morbidity and mortality and to healthcare costs. The emergence of community-acquired MRSA, the zoonotic spread of MRSA and the ongoing burden of MSSA infections further complicate this problem. My work in this area focuses on the development and application of alternative molecular typing methods to improve differentiation and tracking of S. aureus clones in Ireland and the use of high-throughput technologies for screening of S. aureus populations. This has already resulted in the identification of emerging sub-populations of MRSA in Irish hospitals and in circulating community clones with enhanced virulence and/or antibiotic resistance. Coagulase-negative staphylococci are frequently associated with opportunistic human and veterinary infections and can co-colonise mucosal surfaces along with S. aureus. I am currently researching the role that CoNS play in enhancing the antibiotic resistance and virulence potential of S. aureus.

Controlling and preventing the spread of microorganisms in healthcare facilities.

Another research interest is the development of approaches that will help to prevent and control the spread of microorganisms in Irish hospitals. This research includes using novel decontamination strategies, improved screening and hand hygiene and the deployment of rapid detection methods. This has involved the successful development of novel, intelligent and fully automated cleaning systems for managing and controlling biofilms in dental chair unit and associated waterlines and water distribution networks. This technology is currently being investigated for its potential use for environmental decontamination in the hospital environment in collaboration with a major Dublin hospital.

Representative recent publications:

1. Shore AC, Rossney AS, Deasy EC, Brennan OM, Humphries H, Goering RV, Ehricht R, Monecke S, Coleman DC. Identification and molecular characterisation of ACME among ST22-methcillin-resistant Staphylococcus aureus-IV. Antimicrobial Agents and Chemotherapy 2011, 55: in press (epub ahead of print doi:10.1128/AAC.01756-10)

2. Shore AC, Brennan OM, Ehricht R, Monecke S, Schwarz S, Slickers P, Coleman DC. Identification and characterisation of the multidrug resistance gene cfr in a Panton-Valentine leukocidin-positive ST8-methicillin-resistant Staphylococcus aureus-IVa (USA300) isolates. Antimicrobial Agents and Chemotherapy 2010, 54(12):4978-84.

3. Shore AC, Rossney AS, Kinnevey PM, Brennan OM, Creamer E, Sherlock O, Dolan A, Cunney R, Sullivan DJ, Goering RV, Humphreys H, Coleman DC. Enhanced discrimination of highly clonal ST22-methicillin-resistant Staphylococcus aureus IV isolates achieved by combining spa, dru, and pulsed-field gel electrophoresis typing data. Journal of Clinical Microbiology 2010,48(5):1839-1852.

4. Creamer E, Dolan A, Sherlock O, Thomas T, Walsh J, Moore J, Smyth E, O’Neill E, Shore AC, Sullivan D, Rossney AS, Cunney R, Coleman D, Humphreys H. The effect of rapid screening for methicillin-resistant Staphylococcus aureus (MRSA) on the identification and earlier isolation of MRSA-positive patients. Infection Control and Hospital Epidemiology 2010, 31(4):374-381. PMID: 20184438.

5. Coleman DC, O’Donnell MJ, Shore AC, Russell RJ. Biofilm problems in dental unit water systems and its practical control.Journal of Applied Microbiology 2009, 106(5):1424-1437.

6. Shore AC, Rossney AS, O’Connell B, Herra CM, Sullivan DJ, Humphreys H, Coleman DC. Detection of staphylococcal cassette chromosome mec-associated DNA segments in multiresistant methicillin-susceptible Staphylococcus aureus (MSSA) and identification of Staphylococcus epidermidis ccrAB4 in both methicillin-resistant S. aureus and MSSA. Antimicrobial Agents and Chemotherapy 2008, 52(12):4407-4419.

7. Rossney AS, Shore AC, Morgan PM, Fitzgibbon MM, O’Connell B, Coleman DC. The emergence and importation of diverse genotypes of methicillin-resistant Staphylococcus aureus (MRSA) harbouring the Panton-Valentine leukocidin gene (pvl) reveal that pvl is a poor marker for community-acquired MRSA strains in Ireland. Journal of Clinical Microbiology 2007, 45(8):2554-2563.

Full CV