Comparison of Early and Late Loading in the Edentulous Upper Jaw Using Cresco Prosthetic System on Straumann Implants

• implant survival rate [ Time Frame: 1-3 years ] [ Designated as safety issue: No ]
• Adverse events [ Time Frame: at every visit during 3 years ] [ Designated as safety issue: Yes ]

Comparison of early and late loading of implants supporting full each prosthesis in upper jaw, using the Cresco prosthetic system on Straumann implants. The study hypothesis is that there is no difference between the bone loss (or gain) between the groups.

The study is a controlled randomised study whereby each patient will receive 5-6 implants placed in the edentulous upper jaw supporting a 10-12 unit screw-retained fixed partial denture (FPD). The main objective of the study is to evaluate the performance of Straumann implants supporting a FPD using Straumann Implants and Cresco restorative components in early and delayed loading protocols at one year post-loading. The treatment groups consist of an early loading and delayed loading arm using Cresco restorative components loading time 10 days post surgery and at 6-8 weeks respectively. The control group comprise the standard delayed loading protocol (healing period 6-8 weeks) and Straumann restorative components. The primary objective is to compare changes in crestal bone levels on radiographs between implants in the control group and test groups at 1 year.The patients will be followed for 3 years.

• Device: Cresco
  Cresco components loading 10 days post surgery
• Device: Cresco
  Cresco loading at 6-8 weeks post surgery
• Device: Straumann components
  Straumann components loading 6-8 weeks post surgery

• Experimental: Cresco early loading
  The implants must be restored (loaded) with a permanent screw retained fixed partial denture (FPD) at 10 days of post surgery
  Intervention: Device: Cresco
• Experimental: Cresco late loading
  Healing caps will be placed until loading. The minimum waiting time is 4 weeks, but not before "try ins" to ensure a perfect fit. The implants must be restored (loaded) with a permanent screw retained fixed partial denture (FPD) within 42-56 days (6 to 8 weeks) of surgery.
  Intervention: Device: Cresco
• Active Comparator: Straumann system late loading
  Straumann components loading at 6-8 weeks post surgery
  Intervention: Device: Straumann components

Inclusion Criteria:

• Males and females must be at least 18 years of age.
• Be edentulous in the maxilla and subjectively desire an implant supported screw retained FPD
• The teeth at the implant site must have been extracted or lost at least 3 months before the date of implantation.
• In the case of Guided Bone Regeneration(GBR) or Guided Tissue Regeneration (GTR) treatments, these procedures must have been completed at least 6 months prior to intended surgery date (to fulfil point 5).
• Adequate bone quality and quantity at the six, minimum five, implant sites to permit the insertion of Straumann 4.1 and 3.3 mm diameter implants without the use of concurrent bone augmentation techniques. I.e. implant insertion sites must have sufficient bone height such that the implant will not encroach on vital structures and sufficient width that a minimum of 1 mm of palatal and buccal bone will remain.
• Patients must be committed to participate in the study for three years follow-up examinations

Exclusion Criteria:

• Presence of conditions requiring chronic routine prophylactic use of antibiotics (e. g., history of rheumatic heart disease, bacterial endocarditis, cardiac valvular anomalies, prosthetic joint replacements)
• Medical conditions requiring prolonged use of steroids
• History of leukocyte dysfunction and deficiencies
• History of bleeding disorders
• History of neoplastic disease requiring the use of radiation or chemotherapy
• Patients with history of renal failure
• Patients with metabolic bone disorders
• History of uncontrolled endocrine disorders
• Physical handicaps that would interfere with the ability to perform adequate oral hygiene
• Use of any investigational drug or device within the 30-day period immediately prior to implant surgery on study day 0.
• Alcoholism or drug abuse
• Patients infected with HIV
• Patients who smoke more than 10 cigarettes per day or cigar equivalents, or who chew tobacco (not greater than 10 cigarette equivalents)
• 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.
• Local inflammation, including untreated periodontitis
• Mucosal diseases such as erosive lichen planus
• History of local irradiation therapy
• Presence of osseous lesions
• Unhealed extraction sites (less than 3 months post extraction of teeth in intended sites)
• Bone surgery (bone grafts, guided tissue regeneration technique for bone enhancement) at implant placement.
• Severe bruxing or clenching habits
• Persistent intraoral infection
• Patients with inadequate oral hygiene or unmotivated for adequate home care
• Lack of primary stability of 1 or more implant(s) at surgery. In this instance the patient must be withdrawn and treated accordingly.
• Insufficient bone
• Other: Inability to place implants according to protocol requirements