Immediate vs Conventional Loading for Early Implant Placement

The goal of this study is to assess clinical, radiological and patient centred outcomes of immediate and conventional implant loading protocols, and to compare clinical outcomes of these two different loading protocols (immediate and conventional) in combination with early implant placement of single implants in the esthetic zone of maxilla.

Patients with a single failing tooth in the esthetic zone of maxilla (second premolar to second premolar), and in need for implant replacement will be recruited.

During the first appointment, medical history and clinical and radiological evaluations (OPG) will be recorded to verify the eligibility of each subject. If the sufficient bone is present apical to the failing tooth, intraoral scan of the upper jaw will be obtained prior to tooth extraction. Six to eight weeks following tooth extraction CBCT scan will be obtained together with digital impression. The implant positions will be planned according to the bone anatomy and future prosthetic reconstruction. Two groups of treatment protocols will be randomized as following:

Group 1: Early implant placement + immediate provisionalisation; Group 2: Early implant placement + conventional loading.

Implant surgery will be performed by two experienced surgeons. Full thickness triangular flap will be elevated, and fully guided implant placement will be completed. Under-preparation of implant bed in the soft bone will be utilized to obtain adequate primary stability. During the surgery, primary implant stability will be monitored by the means of insertion torque (IT) and resonance frequency analysis (RFA) Contour augmentation will be done for all patients from both groups by means of locally collected autogenous bone chips and deproteinized bovine bone particles, covered by a collagen membrane. Depending on the group, healing cap or healing abutment will be selected, and primary wound closure will be achieved.

Prosthetic rehabilitation:

All impressions will be taken digitally using intraoral scanner and appropriate implant scanbody.

Titanium temporary abutments will be used for provisional restorations, and titanium base abutments for the definitive restoration. Provisional restorations will be made of polymethyl methacrylate (PMMA) (Telio®CAD, Ivoclar Vivadent, Schaan, Lichtenstein) in a digital way. Digital scanning for final restorations and virtual design will be repeated in the same manner. Full ceramic screw-retained crown will be fabricated in a digital way and delivered to the patients.

Group 1:

Immediate screw-retained provisional restoration made of poly methyl methacrylate (PMMA) will be delivered within the first 7 days after surgery. Three months later, final screw-retained full ceramic crown will be fabricated and delivered.

Group 2:

Three months after the surgery, implant will be exposed and provisional screw-retained PMMA restoration delivered. Three months later final screw-retained ceramic crown will be fabricated.

Implant stability will be monitored through RFA. ISQ will be measured in both groups:

* At the day of the implant placement
* At the day of the provisional restoration placement
* At the day of the definitive restoration placement

CBCT scan with a small field of view will be taken prior to implant placement, immediately after implant placement, and 1 year after implant placement. Post-op CBCT scans will be used for measurement of the facial bone wall thickness. Marginal bone level will be monitored using periapical radiographs taken with paralleling technique, using custom silicone holder fabricated for each patient. X-rays will be taken on the day of the provisional restoration placement, final restoration placement, and one year after final restoration.

Esthetic outcome for the peri-implant mucosa will be assessed from the photographs taken at the definitive restoration delivery and 1 year follow-up visit, using pink esthetic score (PES). Patient satisfaction regarding function and aesthetics (mucosa, crown and overall) would be assessed using visual analogue scale (VAS). Quality of life would be examined by OHIP-14 questionnaire. These Patient Reported Outcome Measures (VAS and OHIP-14) would be recorded at 3 time points: before implant placement (baseline), 1 month after definitive crown delivery and after 1 year of function.

Eligibility Criteria:
Inclusion Criteria:

* Single failing tooth in the esthetic zone of maxilla (second premolar to second premolar)
* Patients older than 18 years
* Healthy patients ASA I and II
* Non-smokers/Light smokers (\<10 cigarettes per day)
* Adequate bone volume apical and palatal to the failing tooth to allow for sufficient primary - implant stability of regular diameter implant

Exclusion Criteria:

* Implants adjacent to the failing teeth
* Active periodontal infection
* Severe bruxism
* Systemic or local conditions that contraindicates dental implant surgery - Heavy smokers (\>10 cigarettes per day)