Clinical Performance of Long-span Fixed Partial Dentures

Inclusion Criteria: * The patient is at least 18 years old. * The patient has unrestricted legal capacity. * The patient has two posterior teeth (premolars and / or molars) that are to be replaced next to each other. * The patient is reliable and willing to take part in follow-up examinations regularly and over the entire study period (three years). * The information about the study has been understood by the patient and the signed declaration of consent has been received. Exclusion Criteria: * Pregnancy and lactation * Local and / or systemic acute and / or chronic (also in the past) general medical diseases and conditions that contradict participation in the study and / or expose the patient to a higher risk in the case of participation in the study. * Severe bruxism diagnosed by a portable electrocardiomyography device (BruxOff) (\> 4 bruxism episodes / night) * Reduced clinical crown height (\< 5 mm before tooth preparation) * Limited periodontal health: * probing depths \> 4 mm or = 4 mm and bleeding on probing, * Furcation involvement \> I (first band of the periodontometer after Naber disappears completely) * Degree of loosening of the abutment teeth \> Grade I (\> 1 mm horizontal mobility) * Untreated endodontic problems of abutment teeth * Lack of antagonistic support from fixed dentures or natural teeth * Known allergies or intolerances to the materials used in the study * Lack of oral hygiene * Lack of compliance * Planned change of residence * Rejection of randomisation