Accuracy of Immediate Implant Placement

Immediate implant placement can reduce treatment time and the number of surgical interventions; however, accurate three-dimensional implant positioning can be challenging because the anatomy of the extraction socket does not necessarily correspond to the ideal prosthetically driven implant position. Static computer-guided implant surgery allows the virtually planned implant position to be transferred to the surgical field, but its accuracy may be influenced by the design and stability of the surgical guide.

This randomized clinical study will compare the accuracy of immediate implant placement using three surgical approaches: freehand surgery, conventional tooth-supported static computer-guided surgery, and a tooth- and socket-supported static surgical guide.

Patients aged 20-56 years requiring extraction of a mandibular first or second molar, or a retained root in the same region, followed by immediate implant placement will be considered for enrollment. Eligible participants will be classified as American Society of Anesthesiologists Physical Status I or II, have satisfactory oral hygiene, and be able to comply with the scheduled follow-up protocol. Only Class I extraction sockets planned for rehabilitation with a single-unit screw-retained implant-supported crown will be included.

Participants will undergo standardized preoperative digital assessment, including cone-beam computed tomography and intraoral scanning. The ideal implant position, angulation, depth, and dimensions will be virtually planned according to the available anatomy and intended prosthetic restoration. Participants will then be randomly allocated to one of three groups.

Group 1 will receive immediate implant placement using a freehand surgical approach without a surgical guide. Group 2 will receive immediate implant placement using a conventional tooth-supported static surgical guide fabricated according to the virtual implant plan. Group 3 will receive immediate implant placement using a tooth- and socket-supported static surgical guide designed to obtain stabilization from both the remaining dentition and the extraction socket.

All surgical procedures will be performed by a single experienced clinician under local anesthesia. Atraumatic extraction will be performed with preservation of the extraction socket walls, particularly the buccal cortical plate, and routine flap elevation will be avoided. The implants will be placed according to the allocated surgical protocol and the manufacturer's recommended surgical procedure. Insertion torque and implant stability quotient will be recorded immediately after implant placement.

The primary outcome will be three-dimensional implant placement accuracy. Following implant placement, postoperative cone-beam computed tomography will be obtained and registered with the corresponding preoperative virtual treatment plan. The clinically achieved implant position will be compared with the planned position.

Accuracy will be assessed using coronal deviation, defined as the three-dimensional linear distance between the planned and actual implant positions at the implant platform; apical deviation, defined as the three-dimensional linear distance between the planned and actual implant positions at the implant apex; angular deviation, defined as the three-dimensional angular difference between the longitudinal axes of the planned and clinically placed implants; and depth deviation, defined as the difference in the apicocoronal position between the planned and clinically achieved implant positions.

The study will test the null hypothesis that there are no significant differences in implant positioning accuracy among immediate implant placement performed using freehand surgery, conventional tooth-supported static surgical guides, and tooth- and socket-supported static surgical guides.

• Freehand Immediate Implant Placement (Procedure): Immediate implant placement performed using a freehand surgical approach without a surgical guide.
• Tooth-Supported Static Computer-Guided Implant Placement (Procedure): Immediate implant placement performed using a conventional tooth-supported static surgical guide fabricated according to the virtual implant plan.
• Tooth- and Socket-Supported Static Guided Implant Placement (Procedure): Immediate implant placement performed using a tooth- and socket-supported static surgical guide designed to obtain stabilization from both the remaining dentition and the extraction socket.

Primary outcomes

• Three-dimensional implant placement accuracy [Immediately after implant placement]: Three-dimensional implant placement accuracy will be assessed by comparing the clinically achieved implant position with the preoperatively planned virtual implant position using postoperative cone-beam computed tomography (CBCT) and three-dimensional registration. Accuracy will be evaluated by measuring coronal deviation, apical deviation, angular deviation, and depth deviation between the planned and clinically achieved implant positions.

Sex: All, ages: 20 Years to 60 Years, accepts healthy volunteers

Inclusion Criteria

* Patients aged 20-56 years.
* Patients requiring extraction of a mandibular first or second molar, or a retained root in the same region, followed by immediate implant placement.
* American Society of Anesthesiologists (ASA) Physical Status I or II.
* Satisfactory oral hygiene.
* Ability to comply with the scheduled follow-up protocol.
* Extraction socket classified as a Class I defect.
* Treatment site planned for rehabilitation with a single-unit screw-retained implant-supported crown.
* Adequate primary implant stability, defined as an insertion torque of ≥35 Ncm and/or an implant stability quotient (ISQ) of ≥60.

Exclusion Criteria

* Uncontrolled systemic disease.
* Previous radiotherapy to the head and neck region.
* Active untreated periodontal disease.
* Heavy smoking of more than 10 cigarettes per day.
* Bisphosphonate therapy.
* Severe parafunctional habits such as bruxism.
* Inability to achieve adequate primary stability, defined as an insertion torque <35 Ncm and an ISQ <60.
* Intraoperative detection of loss of the buccal cortical plate.
* Extraction socket defect exceeding Class I.
* Inability to complete the required follow-up protocol.