Esthetic, Clinical and Radiographic Outcomes of Immediately Placed Implants (Type 1) and Early Placed Implants (Type 2)

This controlled, randomized clinical trial (RCT) is designed to compare soft and hard tissue dimensional changes for two commonly used approaches for replacing a recently extracted tooth by means of a dental implant, i.e. immediate implant placement (Type 1) or early implant placement (Type 2). Additionally, this study will evaluate the association between the osseous anatomy and implant position with soft and hard tissue changes.

Extraction sites will include maxillary and mandibular anterior and premolar teeth having intact adjacent teeth. Implants placed for this study will be SLA surface, bone level design, Straumann BL RC (Bone Level Regular Cross-fit ) 4.1mm or BL NC (Bone Level Narrow Cross-fit ) 3.3mm diameter implants at 8, 10, 12 or 14mm in length.

Immediate implant placement (Type 1) resulting in a horizontal defect dimension (HDD) will receive bone grafting, using freeze dried bone allograft (FDBA)(Straumann Allograft GC®) and will be covered by a resorbable membrane (BioGide®).

For the implants randomized to type 2 implant placement, the extraction socket will be filled with a collagen plug and allowed to heal for 4 to 8 weeks before the implant will be placed. Simultaneous guided bone regeneration (GBR) will be performed using FDBA (Straumann Allograft GC®)and a resorbable collagen membrane (BioGide®). The type 2 implant placement procedure will follow the guidelines as described by Buser et al. (2008).

All implant placement will follow standard protocols utilizing tapping and placement according to the manufacturer's guidelines.

Inclusion criteria

• The patient is 18 years or older.
• Ability to understand and provide informed consent before starting the study.
• Ability and willingness to comply with all study requirements.
• The patient, if of child-bearing potential, has a negative urine pregnancy test.
• Adequate oral hygiene to allow for implant therapy consistent with standards of care.
• Adequate bone volume to accommodate the planned endosseous dental implant placement following immediate placement protocols utilizing Straumann Bone Level implants RC 4.1mm or Bone Level Implant NC 3.3 mm at 8, 10, 12 or 14 mm in length.
• One or more teeth in either the maxilla or mandible anterior or premolar areas requiring extraction leading to a single-tooth gap requiring implant placement as determined by the patient's dental provider.
• Following extraction, surgical site anatomy presents conditions allowing immediate implant placement.
• Primary stability of implant consistent with standards of care is achieved at the time of placement.

Exclusion criteria

• Patient reports current smoking habit with moderate or heavy smoking (more than 10 cigarettes per day) or tobacco chewing use.
• History of alcoholism or drug abuse within the past 5 years.
• Severe bruxism or clenching habits.
• Patient has significant untreated periodontal disease (grade III or IV), caries, or clinical or radiographic signs of infection within two adjacent tooth positions of implant area.
• History of HIV infection, Hepatitis B or C.
• Patients with a history of systemic disease that precludes standard dental implant therapy or alters daily activities to a level consistent with ASA III classification (including cardiovascular, hepatic, renal, gastrointestinal, metabolic, neurologic, pulmonary, endocrine, autoimmune, or psychiatric disorders).
• Presence of local inflammation or mucosal diseases such as lichen planus
• Patient history consistent with high risk for subacute bacterial endocarditis
• Current hematological disorder or coumadin (or similar) therapy
• Patient has a disease that affects bone metabolism, such as but not limited to osteoporosis, hyperthyroidism, hyperparathyroidism, congenital connective tissue disorders (e.g., osteogenesis imperfecta), or Paget's disease.
• Patient is taking medications or having treatments known to have an effect on bone turnover, including: thiazide diuretics, calcitonin, systemic steroids, bisphosphonates, vitamin D (>800 IU/day), estrogen or progesterone therapy.
• Current steroid treatment: defined as any person who within the last two years has received for two weeks a dose equivalent to 20 mg hydrocortisone
• Patient currently undergoing chemotherapy
• Patient history of radiation treatment to the head or neck
• Physical or mental handicaps that would interfere with patient's ability to exercise good oral hygiene on a regular basis
• Use of any investigational drug or device within the 30 day period immediately prior to implant surgery
• Patient is pregnant
• Extraction sites having anatomic conditions that preclude immediate implant placement.