Clinical trial NCT04773873: Implant Retained CAD-CAM Ceramic Crowns
Official title: Randomized Controlled Clinical Trial (RCT) of Implant-retained Monolithic Chairside-made CAD-CAM Hybrid Abutment Single Crowns
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Prosthesis Survival
Lead sponsor: University of Geneva, Switzerland
Sponsor class: OTHER
Collaborators: name: ITI Foundation
First posted: 2021-02-26
Enrollment: 90
Sex: ALL
Minimum age (years): 25
Maximum age (years): 70
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
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)
Primary purpose: TREATMENT

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.

Eligibility criteria: 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

Primary outcomes:
measure: survival
timeFrame: 5 years
Secondary outcomes:
measure: Occlusal surface wear
timeFrame: 5 years
Other outcomes:
measure: Bone level
timeFrame: T1, T3 and T5 years
Locations:
city: Geneva
country: Switzerland
facility: University Clinics of Dental Medicine
Study officials:
affiliation: University of Geneva
name: Susanne S Scherrer, Prof, Dr
role: PRINCIPAL_INVESTIGATOR
References: