Monolithic implant-supported lithium disilicate (LS2) crowns in a complete digital workflow: A prospective clinical trial with a 2-year follow-up.

BACKGROUND: The technical development of digital processing allows the production of anatomically full-contoured implant-supported restorations. PURPOSE: The aim of this prospective clinical trial was to analyze the treatment concept of monolithic lithium disilicate (LS2) single-unit restorations in a complete digital workflow. MATERIAL AND METHODS: Forty-four patients were restored with 50 screw-retained monolithic implant LS2 crowns bonded to pre-fabricated titanium abutments on soft tissue level implants (Institut Straumann AG, Basel, Switzerland) in premolar and molar sites. All implant restorations were digitally designed after intraoral optical scanning (IOS) and CAD/CAM-processing without physical model situations. Study participants were clinically and radiographically examined based on an annually performed follow-up. The "Functional Implant Prosthodontic Score" (FIPS) was applied for objective outcome assessment after 2 years of loading. Five variables were defined for FIPS evaluation, resulting in a maximum score of 10 per implant restoration. Descriptive statistics were calculated for mean scores standard deviations, medians, and Q(25) -Q(75) . RESULTS: All patients could be successfully treated within two clinical appointments. No clinical modifications were necessary for the seating of the monolithic crowns, neither for interproximal nor occlusal sites. The implant LS2 restorations demonstrated survival rates of 100% without any technical or biological complications after 2 years. The mean total FIPS score was 7.7 +/- 1.0, ranging from 6 to 10. CONCLUSIONS: CAD/CAM-produced monolithic implant crowns out of LS2 in a complete digital workflow seem to be a feasible treatment concept for the rehabilitation of single-tooth gaps in posterior sites under mid-term observation.