Division of Oral Biosciences
This division is responsible for Laboratory based research in Oral Microbiology and Material Science. (Head of Division – Professor David Coleman).
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.
Microbiology Research Unit
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.
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.
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:
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.
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
- Supervising postgraduate student D. Dent. Ch. research projects