Patients with an edentulous mandible restored with implants who have participated in the core study CR 04/07 will be recruited for this extension study. No further interventions will be made for this extension study other than a clinical follow-up examination and questionnaires. Patients will not receive an investigational treatment in this study. Patients will be followed at 5 to 10 years from the date of the original implant loading

The primary study objective is to compare implant survival with the Titanium Zirconium (Roxolid™) implant compared the Titanium grade IV (SLActive®) implant between baseline (surgery) and 10 years.

The following outcome parameters will be evaluated at 5 and 10 years post surgery for the two different implant types Straumann® Bone Level SLActive, diameter 3.3 mm, Titanium-Zirconium (Roxolid®) vs. Straumann® Bone Level SLActive implant, diameter 3.3 mm, Titanium Grade IV:

• Implant survival
• Implant success according to Buser et al. (1990)
• Crestal bone level change measured by Orthopantomogram (OPT)
• Soft tissue health
• Clinical measurements
• Prosthetic parts assessments: Success and maintenance
• Oral Health Related Quality of Life (OHRQoL)
• Product Safety (Adverse events and device deficiencies)

Inclusion Criteria:

• Subjects must have voluntarily signed the informed consent form
• Patients must be committed to participate in the study until the ten year follow-up examinations
• Subjects must have received treatment in the CR 04/07 core study
• Subjects must have completed 3 year visit of core study

Exclusion Criteria:

• Physical handicaps that would interfere with the ability to perform adequate oral hygiene or attend follow up visits
• Use of any investigational drug or device during the study
• Conditions or circumstances, in the opinion of the investigator, which would prevent completion of study participation or interfere with analysis of study results, such as history of non-compliance, unreliability

Male or female patient ≥ 18 years of age who were provided with an implant supported over-denture in the mandible in the course of the core study (CR 04/07).