What Is CGFI Used For?
CGFI or computer-guided flapless surgery mainly uses cone beam scan technology to be used precisely for preoperative and operative flapless surgery dental implantation. The main advantage of CGFI over a flap surgery-driven implant is that it clearly focuses the jaw bone and the adjacent structure in and around the tissues in terms of detail, depth, visualization, and manipulation.
In this, a flap is not required to drill an implant into the patient's bone surgically, and the surgery itself is based on computer-generated software measurements and templates for the precision of implant placement. Read the article to know the steps of CGFI, the role of CBCT (cone-beam computed tomography) and virtual planning, and the template fabrication that helps in minimally invasive surgical implantation by the dentist.
The computerized surgical guide needed for this can be mainly of three types:
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Tooth-Supported- Partially edentulous arches are used in these guides for reference and stabilization.
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Bone-Supported- The guide is completely supported by the hard tissues, and it requires fixation pins and soft-tissue reflection. These guides are the most accurate ones.
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Mucosa-Supported- These require fixation pins for complete stabilization and are supported by soft tissues just like complete dentures.
Computer-guided flapless implant (CGFI) surgery is well established for fully edentulous patients, and it shows higher accuracy when compared with freehand or operator-done implant placement. Even temporary edentulism or lack of teeth can reduce the quality of life by compromising esthetic, speech, and masticatory elements. The scientific-based evidence for successful immediate loading of an implant is well documented in post-extraction cases (immediate implants).
The increasing demand for patients to have a smooth transition from no dentition to a full-arch fixed implant-supported prosthesis without wearing an interim removable denture has paved the way for these CGFI treatment plans.
The process of CGFI requires multiple steps as compared with 1-piece radiographic guide fabrication, and mistakes may occur in different stages from setting up portion fabrication on the matter model to base portion positioning in the patient's mouth or during CT scan to the radiographic guide fabrication and assembling. These operator or lab-induced errors may compromise the final fit of the surgical guides compared to the preoperative plan and implementation done in CGFI.
The available systematic reviews on the accuracy of CGFI in fully edentulous jaws include multiple drill systems such as MIS, R2Gate, DIO, Megan, 2Ingis, Chromeguide, etc., that allow the operator to perform immediate postextraction implant placement with guided surgery.
What Is the Use of CBCT in Virtual Planning?
Cone-beam radiography is mainly advantageous in visualizing vital anatomic structures, the proximity of the adjacent structures to the implant site, and assessing root anatomy, soft tissue depth, and thickness. The introduction of cone-beam computed tomography (CBCT) is also highly beneficial in volumetric jaw bone imaging and that too at affordable or considerably reasonable costs.
The dose is as per facilitating the preoperative three-dimensional planning of dental implant placement according to a treatment plan that is restoratively kept in view. Different concepts are proposed to transfer virtual digital planning to the surgical field. As in the case of computer-guided implant surgery, static surgical guides are used. The protocol usually involves a sequence of steps, including a radiographic template fabrication, scanning procedure, planning, and implant surgery.
It is essential to avoid operator errors that may occur in different stages, like the following:
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Incorrect acquisition or processing of the image or inaccurate positioning of the guide resulting in displacement or perforation.
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Mechanical errors may be caused by angulation of the drills during perforation, which may, in turn, result in lateral deviations.
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Trismus or reduced mouth opening can interfere with the positioning of the surgical instruments.
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Iatrogenic errors or operator errors as not using the whole length of the drill during perforation.
These errors can accumulate, giving a final inaccuracy of the overall deviation between planning and postoperative outcomes. The introduction of CBCT scanning to implant dentistry as a three-dimensional (3D) imaging tool has led to a breakthrough in this field, mainly because these scanning devices result in lower radiation dosages than conventional CT (computed tomography) scanners.
The use of mucosa-supported guides for flapless implant placement helps limit or considerably reduce the duration of implant surgery, the intensity of pain faced that decreases the analgesic or painkiller consumption, and most other complications that occur typically post-implantation.
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Guided implant placement also facilitates treatment involving immediate restorations as well. The virtual planning is transferred to the manufacturer to fabricate a stereolithographic drill guide.
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A closest-point algorithm is used to match the jaws.
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The established coordinate transformation operations are applied to the 3D representations of the planned and placed implant to allow for relative comparisons between the preoperative and postoperative implant positions.
Is a Radiographic Guide Required?
Radiographic guide fabrication workflow for the edentulous arches or patients with no teeth does not compromise the final fitting of the surgical guide, and neither does it influence the absolute inaccuracy of the implantation in the vertical direction. This aspect is essential because vertical deviation may cause lesions to critical anatomical structures, such as the mandibular or mental nerve injury.
One of the recommended clinical indications for guided implant surgery is the need for minimally invasive surgery, optimization of implant planning and positioning (esthetic cases), and immediate restoration.
Immediately restored implants placed in the socket soon after tooth removal or extraction always seem, as per dental literature, to yield better esthetic outcomes when compared with immediately restored implants placed in healed sites. In the literature, few studies combine computer-guided surgery with implant placement in fresh extraction sockets.
The model described by De Vico et al. uses optical scanning technology, simulated extraction sockets, and wax-up on the planning software. This approach avoids the use of disassembled radiological templates, especially in partially edentulous cases. For full-arch rehabilitation, dental implant specialists prefer a double-guide technique stent.
Conclusion
To conclude, further studies are needed to compare the accuracy and precision of the surgical procedure proposed in this study with newer methods and drill systems available on the market. However, computer-guided flapless surgery remains one of the advanced surgical modalities and a potentially trending future scope in implant dentistry.
