Comparison of Two Collagen Membranes for Bone Augmentation Around Dental Implants Restored with Monolithic Zirconia Single Crowns

The goal of this randomized controlled clinical trial is to compare the use of two covering collagen membranes in a bone augmentation procedure around single implants and to assess three different veneering approaches on crowns in patients lacking a single tooth in the esthetic zone. The main aims include: 1. Bone stability, i.e. the difference in the bone defect depth 4 months after bone augmentation 2. The occurrence of ceramic restoration chipping at the inserted single crowns after 5 years. Participants will receive an implant with simultaneous bone augmentation using the bone particles and a covering collagen membrane. After the healing period, they will receive a crown restoration on the implant. In the surgical part, researchers will compare the commonly used collagen membrane with the compressed (stronger) version of the same collagen membrane in an otherwise identical procedure to evaluate if the compressed membrane offers the same or better bone stability. In the restorative part, researchers will compare three types of crown finishes: non-veneered, conventionally veneered and window-veneered (test group) Participants will be asked to come to follow-up appointments over a period of 7 years. Depending on the follow-up time in the study, different dental measurements will be taken to assess the stability of the implants and restorations.