Prosthetic retention methods are related with the occurrence of complications, such as peri-implantitis. However, scientific valuable data that proof superiority of a specific retention technique are rare. In single-gap implants, screw retention and cementation seemed to achieved comparable results.

In cases of an immediate insertion and loading of implants after a traumatic loss of the patient's own dentition or due to an inevitable extraction of an anterior tooth, it is essential to provide the patient with an adequate provisional crown. A soft-tissue recession must be avoided, whether it is due to a compression of the peri-implant soft-tissue caused by an over-dimensioned restoration in the cervical collar of the provisional crown or to a too small dimensioned sulcus former. A simulation of the exact dimension of the lost tooth - especially on the cervical part of the new provisional restoration - is expected to preserve all relevant information and allows the design of a naturally looking emergence profile. Based on theoretical considerations and a case report, the authors intend to demonstrate that a near-naturally dimensioned sealing of the dento-gingival soft-tissue collar may initiate a tissue-maintaining healing process, similar to a tooth replantation. The natural dental crown, connected to an implant instead of the root, is applied for a tight sealing of the wound. If due to traumatic impact the tooth is no longer available, a naturally dimensioned crown restoration will serve as an alternative wound sealant.

Earlier investigations are confirmed. Width of keratinized mucosa is a risk factor for esthetic predictability of implant-supported crowns in the anterior maxilla in laypersons' ratings. Furthermore, there is an association between the discrepancy of lengths of implant-supported single crowns to their contralateral natural teeth and esthetic satisfaction for all expertise levels.

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PURPOSE The aim of the present randomized controlled study was to compare prefabricated all-ceramic, anatomically shaped healing abutments followed by all-ceramic abutments and all-ceramic crowns and prefabricated standard-shaped (round-diameter) titanium healing abutments followed by final titanium abutments restored with porcelain-fused-to-metal (PFM) implant crowns in the premolar and molar regions. MATERIALS AND METHODS Forty-two patients received single implants restored either by all-ceramic restorations (test group, healing abutment, final abutment, and crown all made of zirconia) or conventional titanium-based restorations. Immediately after prosthetic incorporation and after 12 months of loading, implant survival, technical complications, bone loss, sulcus fluid flow rate (SFFR) as well as plaque index (PI) and implant stability (Periotest) were analyzed clinically and radiologically. RESULTS After 12 months of loading, an implant and prosthetic survival rate of 100% was observed. Minor prosthetic complications such as chipping of ceramic veneering occurred in both groups. No statistical significant differences were observed between both groups with only a minimum of bone loss, SFFR, and PI. CONCLUSION All-ceramic implant prostheses including a prefabricated anatomically shaped healing abutment achieved comparable results to titanium-based restorations in the posterior region. However, observational results indicate a benefit as shaping the peri-implant soft-tissue with successive provisional devices and subsequent compression of the soft tissue can be avoided.