Doelstellingen: The department COPR deals with teaching and research in the domain of restorative dentistry. This encompasses cariology and endodontology, fixed and removable prosthodontics and child dentistry. Research activities are in three projects: 1. corrosion and degradation of dental materials and their effect on reconstituted in vitro epithelium models: Biocompatibility of dental materials using in vitro tests'. The need for biocompatible materials implies the necessity of toxicity testing. The toxicity of a dental material can be evaluated by in vitro tests, animal experimentation including usage tests and clinical studies. In vitro studies are mainly the evaluation of cytotoxicity or genotoxicity. The two most important techniques for maintaining living materials are cell culture and organ culture. Cell and tissue cultures could be very sensitive, practical and the results are quick, cheap and quantitative. In the present study cell/material interactions are evaluated by applying dental materials in the form of soluble components or microparticular corrosion products to artificial, reconstituted oral mucosa models. Corrosion or degradation products will be obtained by exposing material samples to an artificial saliva of defined composition. After cell-material (corrosion products) interaction, changes such as morphological, viability and metabolic alteration will be specified. Complementary to this, clinical studies are performed to evaluate the long-term stability of new composite materials and adhesive amalgam restorations. 2. diagnosis and prevention of early carious and enamel erosion lesions: in cooperation with ETRO (B. Truyen) and CYTO (F. Braet): in this project new observation and diagnostic methods for early enamel lesions are tested in vitro. Using AFM (atomic force microscopy), acid-induced erosion lesions are observed in 'real-time'. The effect of topical fluoride treatment is evaluated and the results are compared with SEM and microhardness tests. Diagnostic tools for the detection of incipent caries lesions are tested using image analysis for traditional and digital X-ray images and analysis of impedance measurements. 3. quality assesment and infection control in endodontic treatment: the failure rate in endodontic treatment is a consequence of faulty technique and insufficient control of (re-) infection. In a combined in vitro/in vivo study the effect of disinfection methods and quality of the covering restauration on microbiology of the root canal are evaluated.