Radiological planning and preparation
Any surgical intervention begins with the analysis of CT data. Sagittal slices performed along the entire length of the jaw with a step of 1–3 mm are of the greatest value. Based on them, 3D modeling and virtual implant navigation software are used, the data from which can be transferred to a surgical guide using CAD/CAM technologies.
An important element of planning is the fabrication of a plastic base guide (Stent). This process is performed by a dental technician: impressions are taken, models are cast, the central maxillomandibular relationship is determined, and a wax-up is performed. A distinctive feature is that all missing posterior teeth are restored in the form of premolars. This reduces the occlusal surface and decreases future masticatory load. The guide with radiopaque markers is used for diagnostics, and after mandatory strict sterilization, as a surgical guide in the oral cavity for bed preparation at a given angle.
Preoperative preparation of the oral cavity necessarily includes sanitation, hygiene instruction, splinting of mobile teeth, and elimination of traumatic occlusion foci via selective grinding. When exposing the neurovascular bundle due to periodontal destruction, pulp removal is indicated. As general therapy, vitamins with microelements, desensitizing and immunostimulating agents are prescribed, and perioperative antibiotic prophylaxis is performed (penicillins, cephalosporins, broad-spectrum antibiotics).
Equipment and surgical access creation
The surgery is performed using a physiodispenser (Physio-Dispenser) — a device with a reduction handpiece. Special burs equipped with an internal capillary are used. Through it, chilled saline solution is supplied directly to the preparation zone, which prevents thermal bone necrosis.
The intervention is performed under local anesthesia with premedication (general anesthesia is rarely used in implantology). The incision is made strictly in the zone of the fixed mucosa of the alveolar process (Attached Gingiva). There are various access options, for example, an incision along the crest peak (Middle Crest). However, shifting the incision lingually or palatally is most justified. In this case, after suturing, the incision line will not be located directly above the implant, which minimizes the risks of infection and exposure of the neck. After reflecting the mucoperiosteal flap, the surgeon visualizes anatomically important areas, such as the mental foramen (mental foramen). In some cases, a flapless technique is permitted — placement through a mucosal perforation without flap reflection.
Bone bed preparation and implant placement
The desired site on the bone is marked with a surgical bur, after which the bone is initially prepared to a depth less than planned. Further bed preparation is carried out strictly with drills for the selected implant type. The main rule is maximum conservation of bone volume (at least 1.5 mm of the wall must remain around the screw). In case of volume deficiency, additional methods are used (guided bone regeneration, splitting, distraction). In the aesthetically significant zone, it is strictly forbidden to remove bone tissue in the area of interdental gingival papillae, as it is a vital foundation for their preservation.
The implant is screwed in using a manual carrier or physiodispenser, and torque-limiting devices (torque wrenches) are used for precise force control. It is recommended to position the platform at the level of the anatomical neck of adjacent teeth — at the bone level or 0.5 mm below it (to compensate for postoperative bone resorption — Remodeling).
The surgery concludes depending on the technique:
- Two-stage technique (Two Phases): a cover screw is installed, and the mucosa is sutured tightly (provides the most reliable osseointegration).
- Single-stage technique (One Phases): a gingiva former is installed.
Conditions for the immediate loading protocol
Immediate prosthetics (placement of a temporary acrylic denture immediately after surgery) requires strict adherence to several criteria:
- Bone quality and protocol: Adequate bone architectonics (type A2) and bed preparation with mandatory cooling.
- Primary stability: Sufficient fixation, which is advisable to monitor using a resonance frequency analysis (RFA) device, the Osstell mentor.
- Implant dimensions: Length greater than 13 mm with a diameter of 3.75 mm, or length from 10 mm with an increased diameter (4.2 mm and more).
- Number of implants (for complete edentulism):
- Mandible: minimum 4 supports for a removable denture and from 6 to 12 for a fixed denture.
- Maxilla: minimum 6 supports for removable prosthetics and 10–12 for fixed prosthetics.
Briefly: answers to topical questions
What are the absolute contraindications for dental implantation?
Absolute contraindications for dental implantation include:
- Chronic diseases in the stage of decompensation.
- Systemic coagulation and hemostasis disorders.
- HIV and any other seropositive infection.
- Mental disorders.
What methods are used in case of bone tissue volume deficiency for implant placement?
In case of bone tissue volume deficiency, additional surgical methods are used to create adequate conditions for implant placement. These include:
- Guided bone regeneration — membrane technique using osteoplastic materials.
- Bone splitting — used for a narrow alveolar ridge using osteotomes.
- Distraction — a method of increasing bone volume.
- Sinus lift (Sinus lifting) — elevation of the maxillary sinus floor.
What bone density types are distinguished during implant planning?
During implant planning, four classes of bone tissue are distinguished in order of decreasing density. According to C. Misch's classification, there are:
- Class D1 — dense cortical bone.
- Class D2 — porous cortical bone with thick trabecular core.
- Class D3 — porous cortical bone with thin trabecular core (compromised structure).
- Class D4 — predominantly trabecular (spongy) bone.
What types of surgical flaps are used in dental implantation?
During surgical access for dental implantation, a mucoperiosteal flap is used. The incision can be made:
- Along the crest of the alveolar process (Middle Crest).
- Slightly vestibular or lingual.
- Slightly lingual or palatal.
In some cases, a flapless technique is used — placement through a mucosal perforation of the alveolar ridge without raising a mucoperiosteal flap.
To remember the conditions for immediate loading in complete edentulism, use the rule "Mandible: 4/6, Maxilla: 6/10". The mandible requires a minimum of 4 implants for a removable prosthesis and 6 for a fixed one. The maxilla requires more supports: 6 for a removable prosthesis and 10 or more for a fixed one.
Class and exam questions
Why are the posterior teeth recreated in the shape of premolars during wax-up of the surgical guide?
This clinically important rule allows making the occlusal surface of implant crowns smaller than that of natural molars. As a result, the masticatory load on the artificial support is significantly reduced.
Why is the implant placed 0.5 mm below the level of the bone crest?
Due to surgical trauma, preparation, and flap elevation, tissue remodeling is triggered. As a result, the height of the alveolar ridge inevitably decreases by an average of 0.5–1.0 mm, which is compensated for in advance by a deeper placement of the fixture.
Why is it recommended to shift the surgical incision lingually or palatally?
Shifting the incision lingually or palatally ensures that the suture line will not be located directly over the implant after closure. The structure will be completely covered by the mucosa, minimizing the risk of exposure and wound infection.
Which technique provides the most reliable osseointegration?
The most reliable osseointegration is achieved using a two-stage surgical technique (Two Phases). The intraosseous portion is closed with a cover screw and sutured beneath the mucous membrane, which guarantees the complete absence of masticatory load during the osseointegration period.
What else to study on this topic
- Techniques for bone deficiency compensation: guided bone regeneration, alveolar splitting, distraction.
- Assessment of primary implant stability using Resonance Frequency Analysis (RFA).
- Peculiarities of perioperative antibiotic prophylaxis (selection of drug groups).
- Laboratory stages of fabricating a plastic base template (Stent).
- Flapless implant placement technique: indications and limitations.
Master the entire topic in the course "Surgical Dentistry"
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- Complete study guide on "Surgical Protocol for Dental Implantation" and 866 more pages of the subject
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Other topics from the section "Chapter 17. Dental Implantology (V.I. Olesova)"
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