Two-unit Cantilever Implant Prostheses Made of Monolithic Zirconia or PFM

Inclusion Criteria: * Minimal age of 22 years old. * No general medical condition which represents a contraindication to implant treatment * Good oral hygiene (PII ≤ 20%), and healthy periodontal tissues (BOP≤ 20%) * Two adjacent-teeth gap in posterior maxilla or mandible arch (first premolar, second premolar, first molar, second molar) with an osseointegrated regular or wide-diameter bone-level implant in a prosthetically correct position to allow occlusal screw-retention. Free-end edentulous gaps can also be included * Presence of antagonist occlusal units Exclusion Criteria: * Severe bruxism or clenching habits * Patients with inadequate oral hygiene or persistent intraoral infection * Women who are pregnant or breast feeding at the day of inclusion * Smokers exceeding 15 cigarettes / day, or equivalent; patients chewing tobacco * Unable or unwilling to cooperate for the trial period * Estimated cantilever crown mesial-distal length \> 10 mm * Estimated implant crown height (from implant platform to occlusal contact points) \> 15 mm