Implant Supported Single Crowns With Different Retention Modes

Implant Supported Single Crowns With Different Retention Modes - Effects on Peri-implant Tissue: A Prospective Randomized Controlled Clinical Trial

This study aims to examine the inflammatory response mediated by MMP-8 (Matrix metalloproteinase-8 ) level in peri-implant sulcus fluid adjacent to screw-retained, cemented or using the Acuris-system fixed single implant crowns as well as changing of the marginal bone level within the first year after implant restoration. Furthermore periodontal parameters, patient satisfaction and possible occurring biological or technical complications will be evaluated.

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