Immediate Implant Placement Surgical Protocol Notes

Immediate Implant Placement

Traditional dental implant placement requires a healing period after extraction and/or graft, delaying final prosthesis placement.
Immediate implant placement aims to shorten treatment time, offering advantages but demanding specific clinical skills.

Classifications of Implant Placement Timing

Immediate: At the time of extraction
Early: 4-6 weeks after extraction
Delayed: 3-4 months after extraction
Late: >4 months after tooth extraction

Objectives of Immediate Implant Placement

Achieve primary implant stability.
Ensure sufficient rigid fixation after healing.
Position the implant ideally for restoration.
Obtain an ideal esthetic result.

Advantages of Immediate Implant Placement

Decreased treatment time and cost by reducing the number of surgical appointments and chair time.
Reduced patient discomfort and morbidity due to fewer procedures.
Decreased the need for bone augmentation, as the implant is placed before significant bone resorption occurs.
Preservation of the soft tissue drape, maintaining gingival architecture and preventing "black triangles" in interproximal areas.
Improved implant positioning by utilizing the existing extraction site.

Bone Resorption After Extraction

If no immediate implant or grafting is completed at the time of extraction, resorption has been shown to result in approximately 1 to 2 mm of vertical bone height and 4 to 5 of horizontal bone width within 1 to 3 years.
At 6 months post-extraction, expect the following:
- Vertical bone loss averaging approximately 1.24 mm (range 0.9–3.6 mm).
- Horizontal bone decrease averaging approximately 3.79 mm (range 2.46–4.56 mm).

Disadvantages of Immediate Implant Placement

Site Morphology: The socket's dimensions often differ significantly from the implant diameter, leading to bony defects.
- For example, a maxillary molar with an 8.0-mm mesial-distal and 10.0-mm buccal-lingual diameter may require a 5.0- or 6.0-mm implant, leaving discrepancies.
Surgical Technique: Requires advanced skills and is more complex than staged protocols.
Achieving primary stability can be difficult due to poor bone density or quantity.
Anatomic Limitations: Deepening the osteotomy to gain primary stability can impinge on vital structures.
- Risk of neurosensory impairments, maxillary sinus or nasal cavity perforation.
- Mandibular posterior: risk of violating the mandibular canal and nerve damage, or lingual plate perforation.
Lack of Primary Closure: Difficult to achieve without large incisions that compromise blood supply.
- Membranes are often required.
- Compromised keratinized tissues may necessitate soft tissue grafts.
Presence of Acute/Chronic Pathology: Increased risk of complications, as residual bacteria may affect healing with higher morbidity.
- Infected sites may have lowered pH affecting bone grafts and implant body contamination.
Consequences of Implant Failure: May lead to significant bone augmentation needs, delaying treatment and increasing costs.
- Replacement implant success rate is approximately 71% for the second attempt and approximately 60% for the third attempt.

Immediate Implant Studies

Lazzara (1989): Documented immediate implant placement with barrier membranes.
Becker et al. (1999): Reported a 93.3% survival rate for immediate implants with grafting and barrier membranes after 1 and 5 years of loading.
Peñarrocha-Diago et al.: Evaluated immediate versus nonimmediate placement for full-arch fixed restorations, with immediate group showing higher success (97.7% vs. 96.3%).

Treatment Planning Considerations: Available Bone

Available bone is crucial for implant placement viability.
Measured in width, height, length, angulation, and crown height space.
Maintain 1.5 to 2 mm of surgical error between the implant and vital structures (e.g., inferior alveolar nerve).
Consider extraction socket dimensions and defects, especially in the labial plate.
Facial cortex is often compromised, requiring bone grafting and/or membrane placement.

Bone Height

Measured from the crest of the edentulous ridge to opposing landmarks.
Anterior regions offer the greatest height, limited by maxillary nares or the inferior border of the mandible.
Maxillary canine eminence region often has the greatest height.
Posterior jaw region: the maxillary first premolar usually has greater height than the second premolar, which has greater height than the molar sites.
Mandibular first premolar region is usually anterior to the mental foramen.
Posterior Nerve Anatomy: Primary stability is frequently achieved using bone apical to the extraction site.
Available bone height affects implant length and crown height, influencing force factors and esthetics.
Vertical bone augmentation is less predictable than width augmentation.

Bone Width

Measured between the facial and lingual plates at the crest of the potential implant site.
The crestal aspect often exhibits greater density, especially in the mandible; lack of crestal bone makes achieving primary stability challenging.
Facial dehiscence defects compromise healing.

Bone Length

Defined as the mesiodistal length of bone in a postextraction area, limited by adjacent teeth or implants.
The implant should be at least 1.5 mm from an adjacent tooth and 3 mm from an adjacent implant.
Compensates for the width of an implant or tooth crestal defect, which is usually less than 1.4 mm.

Bone Angulation

Represents the natural tooth root trajectory in relation to the occlusal plane.
Ideally perpendicular to the plane of occlusion, aligned with the forces of occlusion and parallel with the long axis of the prosthodontic restoration.
Maxillary teeth roots are angled toward a common point approximately 4 inches away.
Mandibular roots flare.
Anterior sextants may have labial undercuts mandating greater angulation or grafting.
Narrower width ridge requires narrower implant designs, causing greater crestal stress.
Limits acceptable bone angulation to 20 degrees from the axis of adjacent clinical crowns or a line perpendicular to the occlusal plane.

Esthetic Risk

Extraction with immediate implant placement may result in nonideal esthetics.
Evaluate lip line, interproximal papilla, tooth shape/shade, existing restorations, and tissue thickness.

Type of Prosthesis

Evaluate and anticipate the final prosthesis dimensions (crown height space) for single-tooth crowns or full-arch prostheses.
In edentulous arches, alveoloplasty may be needed for additional space.
Sufficient crown height space is needed for an overdenture and attachment.

Bone Density

Bone quality/density affects treatment planning, implant design, surgical approach, healing time, and bone loading.
Densest bone is usually in the anterior mandible, with less dense bone in the anterior maxilla and posterior mandible, and the least dense bone in the posterior maxilla.
Johns et al.: Reported higher failure rate in the maxilla (poorer bone quality) compared to the mandible.
Smedberg et al.: Reported a 36% failure rate in the poorest bone density.
Herrmann et al.: Found implant failures strongly correlated to patient factors, including bone quality and volume.

Existing Crown Form

Tapered crown forms may increase the risk for soft tissue compromise after extraction.
Tapered tooth form may be more advantageous for extraction and immediate implant insertion under perfect conditions.
Square tooth form has less gingival shrinkage after extraction.

Anatomic Location

Awareness of bone characteristics will help dictate the appropriate treatment plan.
Bone remodeling is primarily related to the length of time the region has been edentulous and therefore not loaded, the initial density of the bone, and mandibular flexure and torsion.
Immediate implant placement can be performed before the bone density in the jaws begins its usual decline after tooth loss.

Tissue Thickness

Patients with a thin biotype (tissue thickness) are more predisposed to gingival recession and bone loss.
Kan et al.: Reported marginal tissue levels around immediate implants may continue receding up to 8.2 years (mean 4 years) after placement.

Buccal Bone Thickness

Buccal bone is generally thinner than lingual bone and is usually compromised after extraction.
Januario et al.: Evaluated facial bone thickness in the anterior maxillae and determined bone thickness in the tooth sites to be approximately $\leq$ 1 mm thick ( $\leq$ 0.6 mm on average).
After extraction, bone resorbs naturally from buccal to the lingual.
20% of the blood supply from periodontal ligament blood vessels is lost, and over the buccal plate of bone loses 50% of its blood supply.
Complete resorption of the buccal plate may occur after extraction if implant placement or grafting is not completed.

Implant Position

Maxillary anterior: Immediate implants should be positioned more in the lingual aspect of the extraction socket.
Evans and Chen: Implants placed more buccally had three times more soft tissue recession than lingually placed implants (1.8 versus 0.6 mm).
Spray et al.: When <2 mm of bone thickness was present, tissue recession and failure resulted.
Mandibular anterior: Implants should be positioned more toward the lingual, but not as much lingual version as the maxillary anterior.
Maxillary and mandibular posterior: Implants should be positioned in the center of the extraction socket.

Requirements for Immediate Implant Placement

CBCT evaluation confirms sufficient bone quantity (buccal plate bone, bone apical to root apex, palatal bone) and sufficient proximal bone.
Esthetic risk evaluation: Smile line, soft tissue drape, adjacent teeth shade, etc.
Ability to position implant ideally for prosthetic rehabilitation, depending on the anatomic location and available bone.
Ideal primary implant stability is achieved (35–45 N/cm).

Immediate Implant Placement Technique: Step 1

Thorough clinical and radiographic examination using a comprehensive CBCT scan.
Evaluate for possible factors that would lead to immediate placement contraindications.

Immediate Implant Placement Technique: Step 2

Atraumatic tooth extraction to maintain or preserve the surrounding hard and soft tissues.
Begin with a sulcular incision, preferably with a thin scalpel blade or periotome 360 degrees around the tooth.
Avoid soft tissue injury because the periosteum supplies more than 80% of the blood supply to surrounding cortical bone.
Proximal reduction of the tooth will increase space so bone expansion can be completed and also will prevent damage from the adjacent teeth.
If the roots of the tooth to be extracted are divergent, they should be sectioned and removed as individual units.
Periotomes and dental elevators can be used to initiate the luxation of teeth for their removal.

Immediate Implant Placement Technique: Step 3

Debridement of the extraction socket is imperative.
Remove any remnants of periodontal ligament, bacteria, residual infection, dental material, and tooth fragments to affect the osseointegration process.
Serrated spoon curette should be used to scrape the walls of the socket (degranulation) and initiate the regional acceleratory phenomenon (RAP), which enhances the healing process.

Immediate Implant Placement Technique: Step 4

Evaluating the extraction socket for remaining walls of bone with a blunted probe.

Classification of Bony Defects

Five-Bony-Wall Defects: Most ideal condition for a successful immediate implant.
Four-Wall Bony Socket: Requires bone augmentation procedures to obtain an ideal volume and contour of bone.

Treatment Options After Tooth Removal and Bony Wall Evaluation

No treatment: If active infection is present in the extraction site that cannot be completely eradicated.
Bone grafting: If the remaining walls of bone are not advantageous.
Immediate implant placement: If favorable conditions exist.

Immediate Implant Placement Technique: Step 5

Flap Design Three types of flap designs are used for immediate implants: open (buccal and lingual tissue reflected), minimal flap (no buccal or lingual reflection, but minimal flap to expose crestal area), or flapless (tissue punch).

Implant Osteotomy

With a surgical template standard drilling procedures should be completed according to the manufacturer’s instructions.
With the freehand technique, in the maxillary anterior region it is crucial to avoid placing the implant directly in the center of the extraction socket.
Site preparation should always be performed with copious amounts of irrigation with cold saline to reduce heat generation.

Ideal Positioning

Ideal Depth: Requires 2 to 4 mm of bone apical to the inferior part of the socket.
Madani et al.: Reported in a retrospective study that implant placement 1.08 mm subcrestally is the ideal depth of the neck of the implant and that subcrestal placement of the implant greater than 2 mm led to increased bone loss.

Jumping Distance (Maxillary Anterior)

The horizontal bone defect ("Jumping Distance," "Gap") is defined as the distance between the implant and the surrounding wall of the defect.
Botticelli et al.: Reported that in defects of 2 mm or larger, no grafting was needed to grow bone.
Tarnow et al.: Concluded that as long as the buccal plate is intact after the extraction, no bone graft, membrane, or primary closure is needed, irregard- less of how large the defect is.

Lindeman Drill

The author advocates the use of a Lindeman drill (side cutting surgical bur) to initiate osteotomies in extractions side.
This type of bur when used in a “sawing” motion allows for an initial groove to be made that provides for proper and more precise positioning.

Maxillary Anterior Position

A lingually placed implant will also minimize the possibility of apical perforation, which is common when implants are placed in the socket and a parallel walled implant is used.
To achieve primary stability, a minimum torque value has been shown to be one of the most important factors in the success of immediate implants.
The minimum torque has been shown to be approximately 35-45 N/cm in the literature.

Final Emergence Position Based on Prosthesis

For a cement-retained prosthesis, the implant should exit slightly lingual to the incisal edge in the anterior and in the central fossa in the posterior.

Implant Design

Many studies have evaluated the implant design (tapered versus parallel) in the immediate implant protocol.
McAllister et al.: Showed a high success with tapered implants with a high initial implant stability.
Because they are wider coronally, their jumping distance is less, therefore requiring less augmentation.
Implant surface: Many researchers have evaluated rough versus machined surfaces for immediate implants.

Implant Length

Schnitman et al.: Reported that implant lengths greater than 10 mm provide significantly higher success rates for immediate implants.

Implant Stability

The initial stability of the immediate implant is one of the most critical factors in the success of the implant.
There exist two types of implant stability, primary and secondary.

Primary Stability

Defined as the stability of the dental implant immediately after placement; Several methods have been advocated in the literature to determine primary stability.
Percussion is the first test method and can be used to assess primary stability and estimate the amount of bone-implant contact.
Periotest is a testing method that has been proposed to be a more objective method for assessment of implant stability
A more recent method is the use of insertion torque that can be measured with low-speed insertion tools.
Resonance frequency analysis (RFA) is a diagnostic tool that allows for detecting implant stability as a function of the stiffness of the bone-implant interface.

Secondary Stability

During the healing process, the primary stability process is replaced by the biological process of bone healing.
Han et al. reported a decrease in ISQ values within the first 3 weeks after implant placement; then a return to the original ISQ values is observed approximately 8 weeks after surgery.

Grafting/Membrane

After implant stability is confirmed, the present osseous defects are evaluated and grafted accordingly.
In most immediate placement sites it is difficult to obtain primary closure unless the flap is advanced.
Placing implants into infected sites has been controversial.
After 2 years the cumulative survival rate was 100%.

Complications

Not Recognizing 4-Wall Socket

Not Understanding Specific Anatomical Factors

Each tooth in the maxillary and mandibular arch is associated with factors which may make conditions ideal for an immediate implant placement or contraindicate placement.

Inability to Obtain Primary Stability

Primary implant stability may be difficult to achieve in extraction sites where the trabecular bone density is less than ideal.
Mis outlined a protocol that adapts the treatment plan, implant selection, surgical approach, healing regimen, and initial prosthetic loading to all bone densities and all arch positions, which resulted in similar implant success for all bone densities.
Misch initially outlined a protocol that adapts the treatment plan, implant selection, surgical approach, healing regimen, and initial prosthetic loading to all bone densities and all arch positions, which resulted in similar implant success for all bone densities.
Complete Osteotomy Preparation in Appropriate Location and Surgical Sequence
In the anterior maxillary region, immediate implant placement often requires the osteotomy.