Implant Retained CAD-CAM Ceramic Crowns

Not Applicable

Completed

• Conditions: Prosthesis Survival
• Interventions: Device: PFM Crowns on gold coping cast-on; Device: hybrid abutment lithium disilicate crown; Device: hybrid abutment ceramic polymer infiltrated crown

• Registration Number: NCT04773873
• Lead Sponsor: Susanne Scherrer

Brief 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.

Study Timeline

• Study Start: 2015-01-01
• Study First Submitted: 2021-02-22
• Study First Submitted QC: 2021-02-25
• Study First Posted: 2021-02-26
• Status Verified: 2023-12
• Primary Completion: 2023-12-08
• Study Completion: 2023-12-08
• Last Update Submitted: 2023-12-08
• Last Update Posted: 2023-12-11

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 90

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 & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Arm 1: Porcelain fused to metal (PFM)	PFM Crowns on gold coping cast-on	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
Arm 2: Hybrid abutment Lithium disilicate (e.max CAD)	hybrid abutment lithium disilicate crown	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)
Arm 3:Hybrid abutment ceramic polymer infiltrated (Enamic)	hybrid abutment ceramic polymer infiltrated crown	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)

Primary Outcome Measures

Name	Time	Method
survival	5 years	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.

Secondary Outcome Measures

Name	Time	Method
Occlusal surface wear	5 years	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.

Trial Locations

Locations (1)

University Clinics of Dental Medicine; 🇨🇭 Geneva, Switzerland