Implant Retained CAD-CAM Ceramic Crowns (RCT-Scherrer)

Randomized Controlled Clinical Trial (RCT) of Implant-retained Monolithic Chairside-made CAD-CAM Hybrid Abutment Single Crowns

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.

Study Overview

• Status: Completed
• Conditions: Prosthesis Survival
• Intervention / Treatment: Device: PFM Crowns on gold coping cast-on; Device: hybrid abutment lithium disilicate crown; Device: hybrid abutment ceramic polymer infiltrated crown

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.

• Study Type: Interventional
• Enrollment (Actual): 90
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Geneva, Switzerland, 1209
    • University Clinics of Dental Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 23 years to 68 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Absence of relevant medical condition
• Need for a single crown on implant in the molar or premolar region with existing adjacent and antagonist teeth
• No active periodontal or pulpal diseases
• Teeth with good restorations
• Straumann regular (premolar) and wide neck (molar) implants, osseo-integrated for a minimum of 2 months and facial keratinized mucosa width of at least 2 mm
• Patient agrees to return for follow-up examinations during 5 years
• Patient agrees to immediately inform the operator in case of problem

Exclusion Criteria:

• evidence of bruxism
• 2 adjacent implants
• implants placed of-axis

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Arm 1: Porcelain fused to metal (PFM); Implant screw-retained PFM crown fabricated by a laboratory using a gold coping cast-on synOcta gold abutment (Ceramicor) for wide (WN) or regular (RN) neck	Device: PFM Crowns on gold coping cast-on; 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; Other Names: SynOcta gold coping cast-on (Ceramicor)
Experimental: Arm 2: Hybrid abutment Lithium disilicate (e.max CAD); Hybrid crown abutment: chairside-made perforated CAD-CAM Lithium disilicate crown (IPS e.max CAD LT A16) adhesively cemented to a TiBase and screw-retained to a Straumann titanium implant (regular and wide neck)	Device: hybrid abutment lithium disilicate crown; 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; Other Names: hybrid abutment e.max CAD
Experimental: Arm 3:Hybrid abutment ceramic polymer infiltrated (Enamic); Hybrid crown abutment: chairside-made perforated CAD-CAM ceramic-polymer infiltrated crown (Enamic) adhesively cemented to a TiBase and screw-retained to a Straumann titanium implant (regular and wide neck)	Device: hybrid abutment ceramic polymer infiltrated crown; 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 Names: hybrid abutment Enamic

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
survival	The primary aim is to monitor and compare the survival of the two CAD-CAM hybrid abutment crown materials with that of PFM implant screw-retained crowns in the posterior region over a period of 5 years. The survival data is subdivided into "absolute failures" needing replacement of the restoration and "relative failures" which include complications that could be repaired.	5 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Occlusal surface wear	Surface wear generated at occlusal contacts from antagonist teeth will be monitored using silicone replicas of the crowns poured with epoxy resin and gold-cotaed for scanning electron microscopy. The contact wear surface will be expressed in mm^2. The average roughness in Ra values.	5 years

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Bone level	Bone level changes in mm will be monitored through standardized X Rays from registration bites at various time frames (T1, T3 and T5 years)	T1, T3 and T5 years

Collaborators and Investigators

• Sponsor: Susanne Scherrer
• Collaborators: ITI Foundation
• Investigators: Principal Investigator: Susanne S Scherrer, Prof, Dr, University of Geneva

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2015
• Primary Completion (Actual): December 8, 2023
• Study Completion (Actual): December 8, 2023

Study Registration Dates

• First Submitted: February 22, 2021
• First Submitted That Met QC Criteria: February 25, 2021
• First Posted (Actual): February 26, 2021

Study Record Updates

• Last Update Posted (Estimated): December 11, 2023
• Last Update Submitted That Met QC Criteria: December 8, 2023
• Last Verified: December 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Postoperative Complications; Prosthesis Failure; Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Central Nervous System Depressants; Enzyme Inhibitors; Tranquilizing Agents; Psychotropic Drugs; Antidepressive Agents; Antimanic Agents; Lithium Carbonate
• Other Study ID Numbers: RCT-Hybrid abutment

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No