All-ceramic one-piece telescopic abutments for implant-supported overdentures

Removable implant-supported prosthesis should combine easy handling and hygiene, suitable fixation and aesthetic rehabilitation. Especially for elder and manually handicapped patients removable dentures are state of the art. There are different options of anchorage to attach removable overdentures to implants. Telescopic systems are established in conventional prosthetics for a long time. Alternatively to bars or balls telescopic retainers have advantages in implant dentistry concerning retention, maintenance, hygienic aspects, and in divergent implant angulations. Furthermore telescopic retainers enable an uncomplicated integration of implants and natural abutment teeth to support a removable prosthesis. The use of all ceramic abutments offers various advantages like good biocompatibility to peri-implant tissues and low plaque accumulation. Furthermore aesthetic outcome of ceramic abutments is often more attractive to many patients. Conventional telescopic abutments consist of two pieces from metal and ceramic often luted with a resulting gap. Contemporary computer-aided design/computer-assisted manufacturing-technologies allow milling of one-piece abutments from ZrO2 which can be torqued directly to the implant. The aim of this report was to present the application of all-ceramic CAD/CAM milled zirconia one-piece implant telescopic abutments in complex clinical situations. Furthermore options for the integration of natural abutment teeth were demonstrated. In one edentulous maxilla six implants were inserted on bone level. Another patient received four implants in the edentulous maxilla and one implant in the mandible in addition to three natural abutment teeth. Both patients were treated with telescopic anchored prosthesis. All telescopic one-piece implant abutments and the telescopic copings were milled in zirconia by a special CAD/CAM system. To achieve passive fit highly precise electroplated gold meso-structures were luted intraoral with a cobalt-chromium-molybdenum framework. One year follow-ups showed good clinical results. The presented clinical cases demonstrated the application of an alternative type of telescopic abutment from zirconia. The introduced one-piece and gap free telescopic abutment offers advantages compared to conventional two-piece implant abutments. Controlled clinical studies have to prove the success of this restorative option. Keywords: ceramic, zirconia, telescopic abutments, implant therapy outcomes, prosthetic aspects, Straumann CAD/CAM