This thesis investigated different quantitative methods for dental plaque detection using digital imaging. Firstly, based on a commercially available two-tone disclosing, the concentration of the dyes in the blue disclosing solution was calculated. This blue dye was used to disclose dental plaque accumulated on natural teeth and complete upper dentures (on two different backgrounds). Digital images were acquired under visible light, in the n-IR spectrum and with a narrow band-pass interference (NIB) filter tuned to the absorption spectrum of the blue dye. The results showed that disclosing dyes and disclosed dental plaque are transparent in the n-IR spectrum whilst the NIB filter maximised the contrast of dental plaque in the images when using the blue stain. A number of computerised segmentation methods were applied to these images showed automation of dental plaque detection to identify reliable methods to quantify plaque coverage. Although minor human intervention was still required in the segmentation process, the continuous development of new software promises that full automation in plaque quantification is almost a reality. Finally, analysis of the inter- and intra-examiner reliability of the commonly used Quigley and Hein index showed moderate reliability, highlighting the need for automated, quantitative and more reproducible methodology.

This thesis documents the work of Andrew I. M. Greer undertaken for the fulfilment of the requirements for the Degree of Doctor of Philosophy. The project, funded by the EPSRC and MRC, is to develop a nanofabrication processing strategy compatible with titanium based orthopaedic implants. Such a development will facilitate the translation from current and historical in vitro analysis of cell-stimulating nanotopographical cues to in vivo studies upon an implant relevant material. The work presented opens by summarising the social motives and consequences before contextualising the project aims with reference to existing approaches in the field. The thesis progresses through a series of different nanofabrication approaches until an effective strategy satisfying the goals of the project is devised. Thereafter the strategy is explored with its results characterised from a material level through to a biological level. Ultimately the primary goal of the project is realised through the development of novel sol-gel chemistry capable of retaining a nanopattern and transforming into titania, the natural composition at the surface of a titanium based implant. Furthermore, nanofeatures previously too stringent to fabricate for a comprehensive biological study are readily achievable using the documented strategy and fundamental studies have been carried out which indicate that the features concerned are highly effective at up-regulating early indicators of bone formation.