The aim of this study was to evaluate the clinical effectiveness of an Ormocer-based restorative system for treatment of mixed carious and non-carious class V cavities. 70 restorations in 25 patients were placed with the condensable material Admira (group 1). In a second group of eight patients, the treatment of 25 cavities took place with the flowable material Admira Flow in combination with composite-bonded to-flowable technique or with the flowable material alone. The clinical evaluation was carried out using a modified clinical criteria system (Böhm et al. 1991) after Lutz et al. (1977) and Ryge (1980). Restorations of group 1 reached the two-year-level, those of group 2 the one-year-level. Good results were obtained with both condensable material and flowable material despite the small number of failures in the various clinical criteria. The retention rate of the flowable composite was 100% after six and twelve months and was the only parameter superior to those of the condensable material (98.6% resp. 93.9%). After two years, group 1 showed significant differences to base line with respect to volume behaviour and surface texture. No significant differences were determined with respect to of colour match, bond zone morphology and clinical acceptance. A SEM evaluation of replicas confirmed clinical results but also revealed clinically invisible failures of bond zone morphology.