Implant Supported Single Crowns With Different Retention Modes

After giving their written consent volunteers will be screened and eligible subjects will be randomized to three different groups. In group 1 Acuris® is used as fixation type; in group 2 screw retention, and in group 3 cementation is used. After 3 months of submerged healing the dental implants will be restored with all ceramic single implant crowns, fixed by using the randomized fixation mode. Follow-up visits till one year after implant restoration will be performed. At least 11 study visits during 16 months will be conducted.

Inclusion criteria

• capability of giving an informed consent
• good health as defined by the subjects medical history (no contraindications as described in the exclusion criteria below)
• age 18 to 99 years
• Good periodontal status: BOP < 20%, PI < 30%, no PD > 4mm
• No heavy smokers (< 10 cigarettes/day)
• at least 1 missing tooth in the premolar and molar region (with at least a mesial neighboring tooth/implant showing adequate hard- and soft tissue situation without the need of crestal hard- or soft tissue augmentation) either in the maxilla or in the mandible requiring implant therapy for reconstruction, requiring sinus floor augmentation or not.

Exclusion criteria

• Insufficient bone volume for implant placement requiring GBR (guided bone regeneration) procedure in crestal area.
• Heavy Smokers (>10 cigarettes/day)
• Medication with a contraindication for implant therapy (especially antiresorptive therapy, ongoing or recently completed local radiotherapy, systematic diseases, ongoing immunosuppressive therapy, functional disorders like Bruxism).
• Skeletal immaturity.
• Any active malignancy or ongoing treatment for malignancy.
• An active infection (e.g. caries, gingivitis, periodontitis) at or in the neighboring area of the operative site.
• Pregnancy
• unable or unwilling to return for follow-up visits for a period of at least 16 months