Immediate placement of single implants with a definitive crown in the premolar regions: a prospective clinical trial

Descrizione riassuntiva dello studio

This prospective pilot clinical study aims to evaluate the survival of implants after the immediate placement of an implant with immediate loading, followed by a definitive monolithic zirconia crown on the implant in the premolar region, after 6 months. Inclusion criteria include patients aged 22 to 80 years, in good general health, with a failing premolar tooth and sufficient bone volume to ensure primary stability of the implant. Exclusion criteria include smokers, patients showing signs of bruxism, or active infection. The primary objective is to assess the survival of the implant after 6 months, while secondary objectives include evaluating the survival of the restoration, marginal peri-implant bone changes, plaque index (PI), probing depth (PPD), bleeding on probing (BOP), as well as the biological, technical, and aesthetic health of the implants and crowns after 1, 3, and 5 years. The Pink Esthetic Score (PES) and White Esthetic Score (WES) as well as time efficiency will also be measured. Implants will be placed using computer-assisted guided surgery, with BLX type implants (Straumann). After implant insertion, a definitive zirconia crown will be placed immediately. The crowns will be manufactured using CAD/CAM technology and inserted 3-4 hours after implant placement. Time efficiency for impression taking and crown manufacturing will be recorded. This study will involve 10 patients and does not require a power analysis, being a single-arm pilot study.

(BASEC)

Intervento studiato

Patient Selection and Preparation

Eligible patients will undergo cone beam computed tomography (CBCT) to verify that the buccal bone around the failing tooth is intact. After inclusion, intraoral scans and photographs of the failing tooth, adjacent teeth, and soft tissues will be taken. A surgical guide for fully guided implant placement will be designed using planning software (Implant Studio, 3Shape), based on data from the CBCT and intraoral scan. The guides will be manufactured by 3D printing with a clear resin (ProArt Print Splint & PrograPrint PR5, Ivoclar Vivadent). Implants will be positioned prosthetically ideally, 3 mm apically relative to the future gingival margin of the crown.

Preoperative Protocol

Patients will receive preoperative antibiotic therapy (2 g of amoxicillin or 600 mg of clindamycin in case of allergy) one hour before surgery. Tooth extraction will be performed atraumatically, without a flap, under local anesthesia. The patient will continue with the protocol only if the buccal cortex is preserved after extraction.

Implant Placement

Osteotomies will be performed with guided drills (BLX Guided Surgery Set, Straumann). A bone-level implant (diameter 3.75-4.00 mm; BLX, Roxolid®, SLActive®, Straumann) will be placed with a handpiece set to a minimum torque of 35Ncm. A primary stability of at least 35Ncm is required. In case of insufficient stability, a socket seal abutment (SSA) will be used, and the patient will be excluded from the study.

Immediate Loading

The intervention consists of the immediate placement of the implant with immediate loading of a screw-retained monolithic zirconia crown (Zr) on a titanium abutment. After implant placement, a digital impression coping (ScanBody, Straumann) will be placed. Digital impressions (Trios 4, 3Shape) will be taken and sent to the laboratory via the 3Shape Communicate system. A cover screw will be placed during the fabrication of the definitive crown.

Bone and Tissue Grafting

If necessary, the space between the implant and the socket will be filled with bovine deproteinized bone particles (Geistlich Bio-Oss). In case of insufficient soft tissue volume, a connective tissue graft may be performed to enhance gingival stability.

Crown Fabrication and Placement

The monolithic Zr crown will be designed in CAD (Dental System, 3Shape) and manufactured in CAM (Zenotec Select Hybrid, Wieland Dental) by an experienced technician, using translucent zirconia (IPS e.max ZirCAD Prime Gradient, Ivoclar Vivadent). The subgingival surface will be polished to a high shine. The crown will be cemented extraorally onto the titanium abutment with adhesive cement.

Crown Insertion

After ultrasonic cleaning with a cleaning agent, sterile water, and 90% ethanol, the crown will be placed approximately four hours after implant placement. Occlusal and proximal contacts will be adjusted to eliminate static and dynamic interferences. The crown will be tightened to 35Ncm and the access channel to the screw will be filled with Teflon and a temporary material (Telio Inlay, Ivoclar Vivadent). The total time required for the delivery of the crown will be recorded.

Clinical Evaluations and Follow-up

Evaluations will take place:

• Before the operation

• Immediately after the operation

• 12 weeks after the operation

• 6 months after the operation

• 1 year after the operation

• 3 years after the operation

• 5 years after the operation

Outcome Measurements

The study will measure implant stability, bone preservation, soft tissue response, and the success rate of immediate loading.

(BASEC)

Malattie studiate

Patients meeting the inclusion/exclusion criteria and presenting a failing premolar tooth requiring replacement with an implant-supported crown.

(BASEC)

Sponsor

Prof Irena Sailer

(BASEC)

Nome del comitato etico approvante (per studi multicentrici solo il comitato principale)

Commissione d'etica Ginevra

(BASEC)

Data di approvazione del comitato etico

07.05.2025

(BASEC)

Risultati dello studio