Monolithic Zirconia Crowns for Single Implants in the Molar Region: a Multicenter Clinical Trial

Monolithic Zirconia Crowns for Single Implants in the Molar Region: a Randomized Controlled Clinical Trial

The aim of the present study is to test whether or not the use of translucent monolithic zirconia crowns bonded to a titanium base abutment perform similar to porcelain-fused-to-metal crowns on single implants in the posterior region.

In the majority of studies on implant-supported restorations, a considerable rate of fractures of the veneering ceramic was reported. The clinical data is restricted to full-ceramic implant-supported reconstructions in the anterior region. No clinical data is available on the performance of full-ceramic restorations in the molar region.

The use of translucent monolithic zirconia for implant-supported crowns (without veneering ceramic) may reduce the technical complication rate and allow for sufficient aesthetic results in the molar region. To date, no clinical trial investigating monolithic zirconia crowns for single molar implants is available.

The primary outcome of the study is the technical complication rate. This outcome represents an indicator for the prosthetic success of the implant-supported crown. The main biological secondary outcomes are marginal bone level, histological signs of inflammation, and presence of pathogenic bacteria. Further outcomes are crown survival, wear of the crown and of the antagonist.

Inclusion Criteria:

• Informed Consent as documented by signature
• Male and female patients from 18-80 years of age
• Presence of a Straumann Tissue Level implant with a regular platform (4.8 mm diameter platform) in the maxillary or mandibular molar region
• Need for a single implant-supported crown
• Implant position enabling screw-retained crown
• Presence of antagonist

Exclusion Criteria:

• Women who are pregnant at the date of inclusion
• Known or suspected non-compliance, drug or alcohol abuse
• Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc. of the participant
• Smoking more than 15 cigarettes a day
• Poor oral hygiene (Plaque Index over 30%)
• Bruxism