Effect of Placing the Implant Crown on the Implant on the Same Day as the Implant vs. 4 Weeks Later.

Inclusion Criteria: * Age ≥ 20 years * Willingness to sign informed consent and to participate in the study * Plaque index according to Silness and Loe of \< 35% \[26\] * Presence of a mandibular first molar that has to be extracted * Sufficient vertical interocclusal space for the placement of an implant crown (7 mm) * Presence of an opposing natural or artificial tooth * Ridge height sufficient for the placement of a ≥ 10 mm-long implant * Sufficient ridge width for the placement of a 4.1mm diameter implant Exclusion Criteria: * Any physical or mental disorder that would interfere with the ability to perform adequate oral hygiene or the capability of providing written informed consent and compliance to the protocol * Any disorder that would interfere with wound healing or represent a contraindication for implant surgery such as, but not limited to, uncontrolled diabetes or conditions resulting in or requiring immunosuppression, radiation, chemotherapy, frequent use of antibiotics or antiresorptive medication such as bisphosphonates * Pregnancy or lactation * Intention to become pregnant between inclusion and implant loading * Heavy smoking habit with ≥ 10 cig/d * Severe bruxism or clenching habits, present oro-facial pain * Insufficient ridge width/height for the study implant * Defect of any alveolar wall (secondary exclusion criterion at tooth extraction) * ISQ \< 70 (secondary exclusion criterion for Group A at implant placement, for Group B at loading visit)