Pulp Biology, Dental Caries and Mesenchymal Stem Cell (MSC) Repair
A better understanding of molecular changes which occur in the dentine-pulp complex as a result of disease, dental injury and repair, or in response to the placement of dental materials, will enable the development of new biologically-based treatments. Paul has led projects which have developed techniques enabling low-/high-throughput analysis of gene expression in specific dental cell populations. He has also reported on novel molecular and cellular interactions which occur between the inflammatory response or dental restorative materials and pulpal repair processes. Recent PhD projects have characterised dental pulp MSCs, in terms of isolation, expansion and differentiation, and aim to develop novel technologies to enable use of MSCs in dental and medical treatments.
Molecular and Cellular aspects of Periodontal Disease Pathogenesis
Periodontitis is a chronic bacterial infectious disease resulting in gingival recession, bone loss and ultimately tooth loss. The disease is linked with several systemic chronic inflammatory diseases including rheumatoid arthritis (RA), cardiovascular disease and diabetes. Evidence indicates that aberrant host defence mechanisms, likely due to excessive oral epithelial or neutrophilic activity in response to bacteria, underpin the disease. In collaboration with other basic scientists and clinicians, Paul has focussed on the molecular and cellular aspects of disease susceptibility. Studies have identified significant differences in terms of hyper-reactivity/–responsivity in patients’ neutrophils. Subsequently, elevated systemic levels of IFNs were potentially identified as being responsible for this phenomenon and this finding (published in the Journal of Immunology) represents a major advance in the understanding of periodontal disease pathogenesis. These data also led to the proposals that Neutrophil Extracellular Traps (NETs), auto-immunity/-inflammation, DNAse deficiency, epigenetics and efferocytosis may be involved in periodontitis pathogenesis. Currently, Paul is co-supervising cross-College studies characterising the role of NETs and their association in RA and periodontitis.
Tissue Engineering and Biomaterials Interactions
The development of tissue substitutes is required for the repair/replacement of damaged/diseased tissues. In collaboration, Paul has been involved in characterising how mineralised tissue derived cells respond to tissue engineered scaffolds derived from calcium phosphate and alginate materials. As a collaborator Paul has been involved in a recent NIHR funding enabling the study of the development of a light cured resin for use in orthopaedic repair and an extensively NIHR funded (~£1-million) study focusing on the reasons why bone anchored hearing aid titanium implants fail. Paul’s co-supervision of an overseas funded PhD studentship has identified novel methods for generating tissue engineered oral epithelium and its quantitative histological analysis.
Application of micro-computed tomography (CT) technology for dental and mineralised tissue research
Recently, Paul lead a successful Wellcome Trust bid to obtain a CT scanner housed in the School of Dentistry. He oversees the running of the Micro-Computed Tomography (microCT) core-facility which is also widely used throughout the University. Paul has co-supervised 2 PhD projects which have significantly utilised microCT analysis, i) as part of the Physical Sciences of Imaging in the Biomedical Sciences (PSIBs) Doctoral Training Centre (EPSRC) consortium, and ii) in collaboration with the School of Geography in studies analysing prehistoric sharks teeth.
Low Level Light/Laser Therapy (LLLT) or photobiomodulation for application in dental and oral disease treatments
Recent studies in which Paul is involved have begun to show the potential utility of LLLT or photobiomodulatory therapy to promote oral and dental tissue repair, in particular stem cell responses, and to modulate inflammation. In collaboration, the effect of different light wavelengths and irradiation parameters are being explored as potential means to promote dentine-pulp complex, oral epithelial and immune cell responses in relation to tooth repair and periodontitis management.
Assessment of toothpaste abrasives
Work significantly funded by Industry utilises profilometry, gloss analyses and SEM to investigate mechanistic actions of dental dentifrices in oral hygiene and tissue wear.