The use of the cone-in-cone connection to support definitive restorations was previously evaluated in cases involving full-acrylic resin or hybrid acrylic-resin composite prostheses. The aim of this study was to evaluate the performance of definitive fixed partial prostheses made with monolithic zirconia and supported by cone-in-cone abutments and integrated implants. Implants were placed into healed sites and fresh extraction sockets. The prostheses were placed in the posterior regions of partially edentulous patients after healing periods of 3 months. A total of 76 patients received fixed monolithic zirconia restorations splinted with cone-in-cone connections to two implants that were followed up yearly for 5 years. At each follow-up visit, peri-implant bone levels and pocket depths were recorded. Esthetic, functional, and biologic United States Public Health Services parameters modified by the World Dental Federation study design were assessed at the last follow-up appointments. The opposing dentition was categorized by type of restoration and supporting structure at the time of placement of the definitive zirconia partial restoration and at the 5-year follow-up. The treatment achieved an 88.2% success rate and a 97.4% survival rate at the 5-year follow-up. None of the prostheses became loose or detached. One fixed prosthesis (0.76%) fractured 41 months after placement. No significant difference involving peri-implant bone and probing levels between the experimental times was found. The results of this research indicated that abutment-prosthesis cone-in-cone connections were successful within the 5-year study period.

The results of this research indicated that abutment-prostheses coupling connections were successful within the timeframe of this study.

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Purpose To evaluate the performance of definitive, implant‐supported, lithium disilicate fixed dental prostheses (LS2 FDPs) manufactured with a computer‐assisted design/computer‐assisted manufacturing (CAD/CAM) system. All patients received two‐unit restorations placed in posterior regions, supported by osseointegrated implants with cone‐in‐cone connection abutments. Materials and Methods Two implants (Ankylos) were placed into healed sites or fresh extraction sockets in the maxillary/mandibular posterior regions of partially edentulous patients. Definitive digital impressions were made 3 months after surgery. Twenty‐four patients received fixed  monolithic LS2 restorations manufactured with the CEREC system. All restorations were connected to the implants using cone‐in‐cone connection abutments. Peri‐implant pocket depths were recorded for 2 years at each follow‐up visit. Esthetic, functional, and biologic United States Public Health Services (USPHS) parameters modified by the FDI World Dental Federation study design were assessed yearly until the last follow‐up appointment. The opposing dentitions were identified by type of restoration and supporting structures at the time of placement of the definitive restorations and at the 2‐year follow‐up visits. Results One patient (4.16%) moved to an unknown location during the study. A total of 23 FDPs (95.8%) supported by 46 implants reached the 2‐year follow‐up. None of the prostheses failed, or became loose or detached. No significant difference involving probing levels between the experimental times were found. Conclusions The results of this research indicated that the abutment‐prostheses connection using a cone‐in‐cone approach was successful within the 2‐year period of this study. None of the studied monolithic LS2 glass‐ceramic prostheses milled using the CEREC CAD/CAM system fractured or became detached.

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