State of the Art Immediate Implant Placement in the Premaxilla

Preoperative three-dimensional radiograph and intra-oral digital impression:

Required to select eligible patients. All three-dimensional radiographs will be taken with lip retractors.

An intra-oral digital impression of the maxilla will also be taken. Designated software will be used to merge dicoms files (three-dimensional radiograph) and the STL file (intra-oral digital impression) to fabricate a surgical guide.

Surgery:

All surgeries will be performed by two implant surgeons . Patients start to take systemic antibiotics (Amoxicilline 1g) and anti-inflammatory medication (Ibuprofen 600 mg) 1h pre-operatively. Following local anesthesia and oral disinfection the failing tooth is extracted as atraumatically as possible and without raising a flap. Following wound debridement, a cutting implant is installed in an optimal 3D position using a surgical guide. Socket grafting is performed with collagen-enriched deproteinized bovine bone mineral to limit buccal bone resorption and to optimize soft tissue stability. Thereupon, a free gingival graft is harvested from the palatal mucosa in the premolar area and de-epithelialized to arrive at a connective tissue graft (CTG) between 1 mm and 2 mm thickness. Height and length are tailored to the dimensions of the site. Then, the CTG is sutured with two or three single sutures onto the buccal mucosa. Finally, a healing abutment is installed, which is replaced by a provisional implant crown 2 days later. Following provisional crown installation, an intra-oral radiograph is taken. This postoperative intra-oral radiograph is standard in clinical practice, also for patients who are not participating in the study.

When dealing with a shallow non-intact socket (buccal dehiscence < 3 mm = type IIa), the same technique is applied. When dealing with a dehiscence between 4 mm and 6 mm (type IIb), a collagen membrane is applied prior to socket grafting to separate the grafting material from the buccal mucosa. When dealing with a very deep dehiscence (> 6 mm = type IIc), a collagen membrane is also applied and a mixture of C-DBBM and autogenous bone chips (1:1 ratio) is used as grafting material.

Postoperative care:

Patients continue the intake of antibiotics (2 times per day) and anti-inflammatory medication (2 times per day) for 4 days and use a chlorhexidine mouth rinse during 1 week. Sutures are removed 1 week after surgery. At that time point the patient will be asked how many analgesics had been taken, and also the pain intensity will be rated on a numeric rating scale.

These are study-specific evaluations.

Three months after implant installation an intra-oral radiograph is taken to assess osseointegration. This intra-oral radiograph is standard in clinical practice, also for patients who are not participating in the study.

When the implant is successfully integrated, the patient is sent to the general dentist for fabrication of the permanent crown.

1-year registrations:

• Patients' esthetic satisfaction will be assessed on the basis of a numeric rating scale.
• A CBCT will be taken to assess buccal bone thickness at 1 mm, 3 mm and 5 mm below the implant shoulder.
• An intra-oral radiograph is taken to assess marginal bone loss.
• Peri-implant health as clinically assessed on the basis of probing depth, bleeding on probing and plaque.
• Clinical pictures to assess the esthetic outcome of the soft tissues surrounding the crown.
• An intra-oral digital impression will be taken of the upper jaw. The pre-op impression and the one-year impression will be superimposed in designated software to calculate soft tissue changes.

5-year registrations:

• Patients' esthetic satisfaction will be assessed on the basis of a numeric rating scale.
• An intra-oral radiograph is taken to assess marginal bone loss.
• Peri-implant health as clinically assessed on the basis of probing depth, bleeding on probing and plaque.
• Clinical pictures are taken to assess the esthetic outcome of the soft tissues surrounding the crown.
• An intra-oral digital impression will be taken of the upper jaw. The pre-op impression and the five-year impression will be superimposed in designated software to calculate soft tissue changes.

Inclusion criteria

• At least 20 years old
• Good oral hygiene defined as full-mouth plaque score ≤ 25%
• Presence of one or more incisors, cuspids or premolars in the maxilla that need to be extracted for any reason with at least one neighboring tooth present
• At least 3 mm bone available at the apical or palatal aspect of the alveoli as assessed on a three-dimensional radiograph to ensure primary implant stability
• Written informed consent.

Exclusion criteria

• Pregnancy (will be explicitly asked)
• Systemic diseases
• Smoking; suppuration
• > 1 mm gingival asymmetry between the failing teeth and contralateral teeth
• Failing teeth outside the bone envelop as assessed on a three-dimensional radiograph
• Untreated periodontal disease; untreated caries lesions.