4-year PhD Studentship: Osseointegrative and antimicrobial surfaces for dental implant with designed micro/nano-topographies

The use of dental implants has become a common treatment for the replacement of missing or damaged teeth. It is estimated that 10% of the world’s population will need a dental implant in their lifetime. However, still up to 11% dental implants will fail due to simultaneously occurring biomechanical and biological issues such as stress shielding, inappropriate osseointegration and bacterial infections known as peri-implantitis. To increase the clinical success of dental implants, cell-instructive surfaces that enhance the osseointegration process with the host tissues and at the same time prevent or suppress bacterial colonisation are needed. Current approaches are mainly relied on topographic and/or physicochemical modification of the implant surfaces to confer them the ability to induce a biological response and accelerate the bone/soft tissue regeneration process. Commercial dental implants normally use sandblasting and acid-etching to produce micro/nano-roughened surfaces to enhance the osseointegration, but most of them do not possess antimicrobial properties. Nature has shown that some specific micro/nanopatterns are able to control the bacterial adhesion (like on shark skin) and viability (like on cicada and dragonfly wings). Inspired by Nature, these micro/nano-patterned surfaces could be adapted on dental implants to facilitate the osseointegration process while preventing the bacterial colonisation.

Aims and objectives

The aim of this project is to investigate cell-instructive surfaces with combined micro/nano-patterns on two commonly used dental implant materials (titanium and zirconia) to promote osseointegration while preventing bacterial infections. Laser micromachining, plasma and/or alkaline etching will be used to generate well-defined micro/nanopatterns on 3D printed implants and customised root-analogue zirconia implants. The later are gaining increased interest in dental rehabilitation with the advantages of not only preserving more hard and soft tissues but also avoiding a second surgery. Oral bacterial and stem cells responses will be investigated to the designed surfaces with microgrooves with/without superimposed nanowires or nanonetworks.

Methodology

1. Generation and characterisation of micro/nano-patterned surfaces.

Microgrooves with or without superimposed nanopatterns (nanowires and nanonetworks) will be generated on titanium and zirconia composite using laser micromachining and plasma/alkaline etching. The micro/nanopatterned surfaces will be fully characterised using a range of analytical and microscopy techniques including contact angle measurement, chemical composition (XPS, EDX) and feature size and shape (SEM, TEM, microCT).

2. Stem cells response to micro/nanopatterned surfaces

Biocompatibility and osteogenic differentiation of mesenchymal stem cells (MSCs) will be evaluated in vitro. MSC adhesion, growth and viability will be tested at different time points of culture. Immunofluorescence microscopy and SEM will be used to image vinculin in adhesions and cell morphology/interaction with the micro/nanopatterns. Osteogenic differentiation will be evaluated using qPCR to survey transcripts linked to growth and osteogenesis.

3. Oral bacterial response to micro/nanopatterned surfaces

Bacterial viability of the micro/nanopatterned surfaces will be assessed by measurement of bacterial metabolic activity and viability using BacTiter-Glo Viability and Live/Dead assays. SEM will be used to image bacteria-surface interactions. Peri-implantitis associated oral pathogens such as Fusobacterium spp. and Streptococcus spp. will be tested. The antimicrobial properties of 3D printed titanium and CAD/CAM zirconia samples will be tested using a home-made flow cell.

Funding available

This project is open for Bristol PGR scholarship applications (closing date 1st December 2023)

The Bristol PGR scholarship funds tuition fees, the costs of carrying out your research and a maintenance stipend (at the minimum UKRI rate) for the duration of a PhD (four years).

How to apply for this project

This project will be based in Bristol Dental School in the Faculty of Health Sciences at the University of Bristol. Use this information to search for the relevant programme in our online application system.

Please visit the Faculty of Health Sciences website for details of how to apply, the information you must include in your application, and for information about our online Application Workshop to help you submit a competitive application.