In a German dental practice, 299 patients were treated with 1011 ceramic fillings between June 1987 and October 1990. The restorations were produced according to the Cerec method and in each case inserted adhesively at the same appointment. The clinical success was continuously observed and documented. The period in place was between 15 and 18 years. Event criteria were loss of the tooth or of the restoration, fracture with partial loss of tooth and/or restoration, marginal caries, marginal repair and endodontic complication. The probability of success according to the Kaplan-Meier method was reduced after 16.7 years to a value of 84.4%. No further event was observed up to the final time of 18.3 years. If "restoration still in place" is made the basis for the survival analysis, ie, therapeutic measures such as trepanation and marginal correction with composite remain unconsidered, then the Kaplan-Meier value for the observation period is 89%. The size of the filling had no influence on the success prognosis. Premolars achieved a better result than molars. Vital teeth prove to be better than non-vital teeth. The use of dentin adhesives increased the probability of success. A total of 121 events, 86 of these losses of restoration , occurred in the observation interval. The most frequent causes were ceramic and tooth fractures. Keywords: Cerec restorations, clinical long-term study, 18-year results, failure analysis, practical suitability