Related Experiment Video
Updated: Jul 21, 2026

An Improved Mechanical Testing Method to Assess Bone-implant Anchorage
Published on: February 10, 2014
13-year follow-up of a randomized controlled study on zirconia and titanium abutments
Viviane Laura Humm1,2, Irena Sailer3, Daniel Stefan Thoma1
1Clinic of Reconstructive Dentistry, Center of Dental Medicine, University of Zürich, Zürich, Switzerland.
Objectives:
To assess survival rates and compare technical, biological, and esthetic outcomes of customized zirconia and titanium abutments at 13 years post loading.
Materials And Methods:
Initially, 22 patients with 40 implants in posterior regions were included. The sites were randomly assigned to 20 customized zirconia abutments with cemented all ceramic crowns (ACC) and 20 customized titanium abutments with cemented metal ceramic crowns (MCC). At a mean follow-up of 13.4 years, patients were examined and implants/restorations assessed for survival and technical complications, as well as biological and esthetic outcomes (pocket probing depth [PPD], bleeding on probing [BOP], plaque control record [PCR], bone level [BL], papilla index [PAP], mucosal thickness, and recession (distance of the margo mucosae [MM]/margo gingivae MG)). Descriptive analyses were performed for all outcome measures.
Results:
Fifteen patients with 21 abutments (13 zirconia, 8 titanium) were examined at 13 years. The drop-out rate was 25% (patient level). The technical survival rate of the abutments was 100%. The survival rate on the restorative level (crowns) was 100%. The assessed biological outcomes (PPD, PCR, BOP, BL) and esthetic outcomes (MG, PAP) were similar.
Conclusions:
Zirconia and titanium abutments supporting single implant-borne restorations rendered a high survival rate and minimal differences in terms of technical, biological, and esthetic outcomes at 13 years of follow-up.
Related Concept Videos
Naturalistic Observations
Longitudinal Research
Cross-Sectional Research
Observational Studies
There are three types of observational studies – Prospective, retrospective, and cross-sectional.
Prospective Study
Prospective studies, also known as longitudinal or cohort studies, are carried out by collecting future data from groups sharing similar characteristics. One example of...
Longitudinal Studies
Typical Model Studies

