Computer Guided Immediate Implant Placement in Mandibular Molars Using Patient Specific 3D Printed Polylactic Acid Graft Versus Conventional Immediate Implant Placement With Xenograft

This is a prospective randomized controlled clinical trial designed to evaluate computer-guided immediate implant placement in mandibular molar extraction sockets using a patient-specific 3D-printed polylactic acid (PLA) socket guide and customized root-form PLA graft, compared with conventional freehand immediate implant placement using xenograft.

Immediate implant placement in mandibular molar extraction sockets can be challenging because of the wide socket morphology and the limited amount of bone available for achieving primary implant stability. The interradicular septum and apical bone are important for implant anchorage, while the irregular shape of the extraction socket may make conventional freehand osteotomy preparation and implant positioning difficult.

In the experimental group, preoperative cone-beam computed tomography (CBCT) data will be used for three-dimensional digital planning of the implant position. The implant position, angulation, diameter, and length will be planned using Blue Sky Plan 4 software. A patient-specific socket-supported PLA surgical guide will then be designed according to the planned implant position. A customized root-form PLA graft will also be designed to fit the peri-implant gap within the extraction socket.

The PLA socket guide and customized PLA graft will be fabricated using additive manufacturing. The patient-specific guide will be used during osteotomy preparation to control the drilling trajectory and facilitate placement of the implant according to the digitally planned position. The customized PLA graft will be positioned within the residual gap between the implant and extraction socket walls.

Participants allocated to the control group will undergo conventional immediate implant placement using a freehand surgical technique. Xenograft will be used for grafting of the peri-implant gap according to the conventional treatment protocol.

All participants will undergo preoperative clinical and radiographic assessment. Clinical assessment includes medical and dental history, periodontal assessment, occlusal assessment, and plaque-control assessment. CBCT will be used to evaluate the extraction socket, root morphology, interradicular bone, and available bone dimensions before implant placement.

The primary outcomes of the study are implant primary stability and implant positional accuracy. Implant stability will be assessed using resonance frequency analysis/implant stability measurement at the time of implant placement and during follow-up. Implant positional accuracy will be assessed by comparing the virtually planned implant position with the actual postoperative implant position using CBCT-based evaluation. Positional accuracy will be assessed as a single positional accuracy outcome incorporating the measured deviations between the planned and actual implant position.

Participants will be followed clinically during the healing period, with assessment of implant stability at the planned follow-up period. A postoperative CBCT examination will be used to evaluate the actual implant position and compare it with the preoperative virtual plan.

The study is intended to determine whether the patient-specific 3D-printed PLA socket guide and customized PLA graft can improve primary implant stability and the accuracy of immediate implant placement compared with the conventional freehand technique using xenograft.

Inclusion criteria

• Patients requiring immediate implant placement in mandibular molar extraction sockets.
• Patients with adequate bone volume to accommodate the planned implant.
• Patients willing to undergo immediate implant placement and follow-up for 6 months.
• Patients who provided informed consent.

Exclusion criteria

• Uncontrolled systemic diseases or medical conditions contraindicating implant surgery.
• Patients receiving medications or treatments that may adversely affect bone healing.
• smokers.
• Poor oral hygiene or uncontrolled periodontal disease.
• Acute uncontrolled infection at the surgical site.
• Conditions requiring additional bone augmentation beyond the study protocol.
• Patients unable or unwilling to attend the required follow-up visits.