Implant Retained CAD-CAM Ceramic Crowns
Condition: Prosthesis Survival
MeSH terms: Prosthesis Failure
Study type: Interventional

Summary: 
      Newly available ceramic CAD-CAM blocs containing a screw channel for chairside-made crowns to
      be adhesively cemented to a TiBase abutment and screw-retained to an implant are appealing to
      the clinician, considering the time efficiency (one appointment) and overall lower costs as
      no dental laboratory is involved. The hypotheses are that the biological (BOP, PD, PCR,
      implant bone level) and mechanical outcomes (fracture, loss of retention, wear) are
      equivalent to implant screw-retained Porcelain-Fused-to-Metal (PFM) crowns over a 5 year
      observation time.This RCT will provide key information as to the cost/benefit, suitability
      and/or limitations of these chair-side hybrid-abutment crowns in the posterior region.
    

Detailed description: 
      This RCT involves the University of Geneva Dental School and four private practices for which
      the Geneva Hospital Ethic Committee's approval is required. Patients in need for replacement
      of single unit posterior teeth will be recruited at the Dental School as well as in the 5
      private practices based on specific selection criteria. Patients will be randomly assigned to
      a restorative group using a computer-generated random number table for allocation.

      The CAD-CAM blocs containing a screw channel for implant-retained chairside-made single-unit
      hybrid-abutment crowns are 1) Lithium-disilicate glass-ceramic (e.max CAD) (G1) and 2)
      feldspath-ceramic infiltrated by polymer (Enamic) (G2). The CAD-CAM crowns are adhesively
      cemented to titanium base abutments (Ti-base) and screw-retained to Titanium implants
      (Straumann Standard Plus) in the premolar (RN) and molar region (WN). Controls are
      screw-retained PFM crowns (G3). The number of crowns in each group is N=30 (15 molars and 15
      premolars) which gives a total of 90 crowns for this study.

      Participants are recalled after 1 week-10 days after crown insertion (baseline, T0) and then
      yearly during 5 years (T1-T5). Digital X-Rays are taken at T0, T1, T3 and T5 with
      repositionable individual resin bite registrations.
    

Intervention name(s): PFM Crowns on gold coping cast-on; hybrid abutment lithium disilicate crown; hybrid abutment ceramic polymer infiltrated crown
Intervention type(s): Device; Device; Device
Intervention description(s): Classic impressions are taken by the operators and sent to one and same laboratory who will deliver all the screw-retained PFM restorations. The crowns will be made using a gold coping cast-on synOcta gold abutment (Ceramicor) for wide (WN) or regular (RN) neck; Intraoral digital impression with respective scanbodies (Sirona) for Cerec OmniCam or Cerec Bluecam over the chosen TiBase. Cerec CAD designing (operator) and CAM milling (Cerec MCXL) of single crowns with perforated blocs (e.max CAD). crystallization/ characterization/ glaze firing for the e.max CAD crown using an oven with specific firing programmes for e.max CAD. Adhesive cementation steps of the ceramic crown onto the TiBase; Intraoral digital impression with respective scanbodies (Sirona) for Cerec OmniCam or Cerec Bluecam over the chosen TiBase. Cerec CAD designing (operator) and CAM milling (Cerec MCXL) of single crowns with perforated blocs (Enamic). Surface polishing with rubber polishers. Adhesive cementation steps of the ceramic crown onto the TiBase
Other intervention name(s): SynOcta gold coping cast-on (Ceramicor); hybrid abutment e.max CAD; hybrid abutment Enamic
Intervention MeSH terms: Lithium Carbonate
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: 90 RCT crowns will be allocated in three groups of ceramic materials (3 materials) and at two tooth locations (premolar and molar)
Masking: None (Open Label)
Primary purpose: Treatment