Evaluation of Immediate Versus Delayed Loading of Dental Implants With a Modified Surface

This study is a post-market randomized study whereby each patient will receive 1 to 4 implants placed in the posterior maxilla or mandible. The primary objective of this randomized open study is to evaluate the performance in immediate and delayed loading (4 weeks) of Straumann standard solid screw 4.1mm and the 4.8 mm diameter wide neck implants with a new surface. These implants will support single crowns or 2 to 4 unit bridge restorations in the posterior maxilla or mandible and the treatment will be evaluated for the immediate and delayed loading procedures at one year post surgery. Patients will be allocated into two groups and then randomized into immediate or delayed loading arms.

Inclusion criteria

• Males and females must be at least 18 years of age
• Have at least one missing tooth in positions FDI 4, 5, 6, or 7 in any quadrant (ADA positions 2, 3, 4, 5; or 12, 13, 14, 15; or 20, 21, 22, 23; or 28, 29, 30, 31.)
• Subjects desire an implant supported restoration on1 to 4 implants per quadrant
• The tooth/teeth position(s) at the proposed implant site must have been extracted or lost at least 4 months before the date of implantation and be fully healed
• Adequate bone quality and quantity at the implant site to permit the insertion of a Straumann standard 4.1 mm diameter implant of at least 8 mm length without the use of concurrent bone augmentation techniques. If more bone is available and is indicated a Straumann standard 4.8 mm diameter implant with a wide neck of at least 8 mm length may be used, 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 bone lingual and buccal bone will remain
• The opposing dentition must be natural teeth or fixed crowns or bridges on natural teeth or implants. Removable prostheses or dentures opposing the study implants are not allowed
• Patients must be committed to the study for its full duration.

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 chemotherapy
• History of radiation therapy to the head and neck
• Patients with history of renal failure
• Patients with severe or uncontrolled metabolic bone disorders
• 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 >10 cigarettes per day or cigar equivalents, or who chew tobacco
• 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, or 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 4 months post extraction of teeth in intended sites)
• Bone surgery (bone grafts, guided tissue regeneration techniques for bone enhancement) prior to implant placement unless performed more than 6 months prior to implant placement and the site fully healed. Note: Minor bone enhancement using harvested bone from the implant site and a resorbable membrane is allowed at the time of implant placement
• Patients requiring bone grafting at the surgical sites at the time of surgery.
• Severe bruxing or clenching habits
• Persistent intraoral infection
• Lack of primary stability of one (or more) implant(s) at surgery. In this instance the patient must be withdrawn and the patient treated accordingly
• Patients with inadequate oral hygiene or unmotivated for adequate home care