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

Susanne Scherrer

Status: Completed

Conditions: Prosthesis Survival

Treatments: Device: PFM Crowns on gold coping cast-on; Device: hybrid abutment lithium disilicate crown; Device: hybrid abutment ceramic polymer infiltrated crown

Study type: Interventional

Funder types: Other; Industry

Identifiers

NCT04773873

RCT-Hybrid abutment

Details and patient eligibility

About

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.

Full 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.

Enrollment: 90 patients

Sex: All

Ages: 25 to 70 years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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90 participants in 3 patient groups

Arm 1: Porcelain fused to metal (PFM)

Active Comparator group

Description:

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

Treatment:

Device: PFM Crowns on gold coping cast-on

Arm 2: Hybrid abutment Lithium disilicate (e.max CAD)

Experimental group

Description:

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)

Treatment:

Device: hybrid abutment lithium disilicate crown

Arm 3:Hybrid abutment ceramic polymer infiltrated (Enamic)

Experimental group

Description:

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)

Treatment:

Device: hybrid abutment ceramic polymer infiltrated crown