title: Clinical performance of screw-retained and cemented implant-supported zirconia single crowns: 36-month results.
abstract: OBJECTIVE
  The objective of this clinical study was to evaluate the clinical performance of implant-supported zirconia crowns with a sintered veneering cap. Furthermore, the influence of the type of retention (screw-retained vs cemented single crowns) was analysed.
  
  
  METHODS
  Fifty-eight patients were accommodated with 114 implants, inserted in the molar and premolar regions. Zirconia-based crowns with a sintered veneering cap were either screw-retained (n = 53) or cemented (n = 61) on the implant. Recalls were performed every 6 months. The state of soft tissue was documented by the modified plaque and gingiva index (mPI) and sulcus bleeding index (mSBI). The restorations were evaluated for technical failures like veneering porcelain fractures, surface qualities and marginal fitting.
  
  
  RESULTS
  Neither implant loss nor crown fractures occurred. After a mean clinical service time of 36.9 months, fractures of the veneering porcelain were registered in 1.8 % of the cases. The Kaplan-Meier survival probability regarding eventless restorations was 98.2 %. Chipping of the veneering porcelain was registered in two cemented crowns without statistical influence of the type of retention. The indices showed healthy soft periimplant tissues in both groups.
  
  
  CONCLUSIONS
  Implant-supported zirconia crowns with a sintered veneering cap demonstrated good clinical performance. The type of retention had no influence on technical complications.
authors: , Weinstrasse 4, 80333, Munich, Germany.
authors: Claudio
authors: C
authors: Cacaci
authors: , Weinstrasse 4, 80333, Munich, Germany.
authors: Friederike
authors: F
authors: Cantner
authors: Department of Oral and Maxillofacial Surgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany.
authors: Thomas
authors: T
authors: Mücke
authors: , Weinstrasse 4, 80333, Munich, Germany.
authors: Peter
authors: P
authors: Randelzhofer
authors: , Briennerstrasse 7, 80333, Munich, Germany.
authors: Jan
authors: J
authors: Hajtó
authors: Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, University Charité Berlin, Assmannshauser Straße 4-6, 14197, Berlin, Germany. florian.beuer@charite.de.
authors: Florian
authors: F
authors: Beuer
mesh_terms: D000328:Adult; D000368:Aged; D001641:Bicuspid; D001863:Bone Screws; D003442:Crowns; D003738:Dental Cements; D003774:Dental Plaque Index; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008963:Molar; D010512:Periodontal Index; D011446:Prospective Studies; D016896:Treatment Outcome; D015040:Zirconium
chemical_list: D003738:Dental Cements; D015040:Zirconium; C028541:zirconium oxide
keywords: Cementation; Implant-supported crown; Implat; Screw retention; Single crown