|Year : 2022 | Volume
| Issue : 2 | Page : 64-67
Implant guides: A literature review
Chandan Kumar Kusum, Niyati Varshney, Anshul Trivedi
Department of Prosthodontics and Crown and Bridge, Subharti Dental College and Hospital, Swami Vivekanand Subharti University, Meerut, Uttar Pradesh, India
|Date of Submission||06-Feb-2022|
|Date of Decision||23-Mar-2022|
|Date of Acceptance||07-Apr-2022|
|Date of Web Publication||20-Jun-2022|
Dr. Niyati Varshney
Department of Prosthodontics and Crown and Bridge, Subharti Dental College and Hospital, Swami Vivekanand Subharti University, Meerut, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
In spite of significant developments in technologies and techniques, the correct positioning of dental implants remains an arduous task. Diagnostic casts and orthopantomogram do not provide the three-dimensional radiographic information essential for proper placing and orientation of the dental implant, which might lead to unforeseen results. Prosthetically guided implantology became the need for successful outcomes. In this concept, the ideal placement of an implant is determined by the final restoration and its correlation with adjoining structures. Three-dimensional radiography, considered to be the gold standard in implant planning in terms of accuracy, fails in meeting its objectives unless the data acquired are transferred with any guide or template. Various designs and sorts of implant guides have been described, ranging from basic designs that just indicate the appropriate implant site to extremely complicated designs that, while requiring a significant amount of time and money, guide the entire surgical procedure. This review article seeks to discuss the recent advancements in implant guides.
Keywords: Accuracy, dental implant, dynamic navigation, freehand approach, ideal placement, static navigation
|How to cite this article:|
Kusum CK, Varshney N, Trivedi A. Implant guides: A literature review. SRM J Res Dent Sci 2022;13:64-7
| Introduction|| |
Dental implants have gained immense popularity as a treatment modality for the rehabilitation of partially or completely edentulous patients. Implants have significantly improved patient satisfaction, esthetics, and the overall quality of life in comparison to the conventional prosthetic treatment options. The success rate of dental implants is influenced by the patient's examination, treatment planning, and execution of surgical skills.,,
The need for exact implant placement inspired the emergence of the concept of prosthetically guided implantology. This concept dictated that accurate position and angulation of implants are determined initially during the diagnostic stage.,
A slight deviation from the planned placement may not yield the optimum outcome, thus the surgical guide templates are considered crucial to maintain logical continuity throughout the diagnosis, prosthetic planning, and surgical phases. These implant guides upgrade the precision of dental implant positioning, reduce futile osteotomy, and sidestep other probable perils accompanying surgery, thereby decreasing surgical time and trauma and increasing patient compliance.,
The electronic literature search was conducted from May 2015 to December 2021 using MEDLINE (PubMed) and Google Scholar for articles in the English language published in journals of dentistry using the following search terms: “dental implant and ideal placement,” “fabrication of implant guides,” “static guides,” “dynamic guides,” “guides and accuracy,” and “implant guides and zygomatic implant.” Thus, this literature review focuses mainly on the fabrication techniques of implant guides and its advancements in detail.
| Fabrication|| |
Three basic fabrication techniques that are commonly used for implant guides fabrication are conventional freehand technique, analog milling using a dental surveyor, and computer-aided design/computer aided manufacture (CAD/CAM) technology. With the advancement in implant imaging and three-dimensional implant planning programs, digital-aided implant surgeries have become popular., Many studies reveal that the computer-guided approach for implant placement has significantly greater accuracy and predictability than the conventional freehand approach, thus alleviating the occurrence of implant positioning errors.,,,,,
Digital guides can be manufactured using additive or subtractive techniques. The subtractive approach produces more homogeneous structures with sufficient accuracy, making it suited for intraoral prostheses with high occlusal forces, while the larger workpieces with high surface variation, better accuracy, and no raw material wastage are produced using additive manufacturing processes.
Broadly, the procedure of CAD/CAM-based surgical guide fabrication can be divided into the following steps:
- Fabrication of the radiographic template
- Computerized tomography scan or data acquisition
- Virtual implant planning, and
- Fabrication of the stereolithographic (SLA) drill guide.
Fabrication of radiographic template
The radio-opaque marker barium sulfate is commonly used in the fabrication of radiographic templates. Another option is to use a duplicate denture with radio-opaque markers in the center of the occlusal surfaces of the teeth, matching the screw access holes of the implant-supported prosthesis.
Computed tomography scan procedure/data acquisition
The spiral or volume acquisition computed tomography (CT) scanning procedure is performed with the radiographic template in place.
Virtual implant planning using interactive planning software or 3D computer simulation
The surgeon and prosthodontist can simulate implant placement on the 3D model in conjunction with the parasagittal views using software such as Columbia Scientific Incorporated, Columbia, Nobel Guide, Nobel Biocave, Yorba Linda, California, I Dent Imaging Ltd., Hasharon, Israel, coDiagnostiX, and others. Specific dimension implants are selected, and their 3D replica is created on the computer model of the patient's jaw.
Fabrication of stereolithographic drill guides
The SLA comprises a vat with a liquid photo-polymerized resin, which is polymerized in 1-mm cross-sectional increments specified during the CT formatting method. The vat completes around 80% of the overall polymerization, while the rest can be completed in a routine ultraviolet light-curing machine. Similarly, surgical templates are fabricated by connecting a sequence of minute triangles to the surface anatomy of the SLA model. Based on the surgical flap design, the extent of the buccal and lingual flanges can be predetermined. The diameter and angulation of the simulated implants are also recognized by the SLA machine, which selectively polymerizes resin around them, generating a cylindrical guide for each implant. The supporting resin triangles are swapped with surgical-grade stainless steel tubes from the cylindrical guide. Surgical templates are manufactured in this way, with metal sleeves corresponding to each fixture location and seating directly on the bone.
Static navigation and dynamic navigation are the two most popular among the various digital guide systems. While studies state no superior accuracy of dynamic navigation over static navigation,,, there are few other studies that prove dynamic navigation superior to static systems in terms of accuracy and precision for implant placement.,
| Static Navigation|| |
The static- or template-based system helps to communicate with predetermined sites using rapid prototyped guides in the operating field. The term “static” refers to a fixed implant positioning and does not allow for real-time monitoring of the implant placement procedure. Any intraoperative position is not possible without the removal of guide. These guides have become the most widely recommended guides available in the field of implant dentistry, especially for edentulous patients. For edentulous patients, static guides are indicated when a flapless technique is advocated, bone reduction is planned, or in full-mouth fixed prosthetic treatment.
Less intrusive surgery with less patient morbidity and a flapless approach make static guides superior. These guides restricts access to bone, leading to restraint irrigation of the drill throughout the procedure and thus potentially increasing heat output. Using static guides for implant placement is a challenge in insufficient mouth opening cases. This issue is exceptionally noticeable in the molar region, thus restricting its use in this area.
| Dynamic Navigation|| |
The dynamic system communicates through visual imaging devices with a virtual treatment plan to the operative area. This system uses a tracking array to perceive and track the position of optical reference markers placed.
Optical technology uses either active or passive tracking arrays to trace the patient and the handpiece while viewing the images on display. Active system arrays radiate light tracked by stereo cameras, whereas passive systems utilize tracking arrays that reflect light emitted from a light source back to the stereo cameras.
During cone-beam CT (CBCT) scanning, a passive optical dynamic navigation system involves the use of fiducial markers firmly mounted to the patient's maxillary or mandibular arch. With the addition of an array, the fiducial markers allow for registration of the arch to the cameras. The array is joined to the clip that holds the fiducial markers and is positioned extraorally. The implant handpiece, in addition, contains an array, which, when paired with these markers, enables triangulation and, as a result, precise navigation. To accurately trace on display, the drill and patient-mounted arrays ought to be within the line of sight of the overhead stereo cameras.
It is recommended to utilize dynamic navigation in limited mouth opening, in difficult-to-reach areas, in same-day implant insertion surgery, and in tight interdental spaces conditions where static guides are ineffective. High precision, speed, and cost-effectiveness, as well as the flexibility to adjust implant size, system, and placement during surgery, are indeed assets. A collaborated team approach is also required for dynamic navigation. Its application is limited due to its sensitivity to reflections and interference with the line of sight betwixt the sensors and the cameras, as well as its higher cost, strict intraoperative referencing, and steep learning curve.
| Recent Advancements|| |
Zygomatic implant guides
Although zygomatic implants are commonly placed without the use of surgical guides, various methods have been documented that use initial drilling guides, with the implant still being manually inserted once the guide is removed. Limited access, poor sight during surgery, the flexibility of lengthy twist drills, and the curved or uneven bony surface at the base of the zygoma can all hinder the correct apical placement of the implant in the intended optimum position within the zygoma.
Due to the intricacies of zygomatic implant placement, meticulous preoperative preparation and transfer to the operating field are required. The bulk of available zygomatic implant guides provide for control of the implant's entrance site and emergence at the alveolus but not its trajectory or apical exit location within the zygoma. Metal drill guides, on the other hand, have just recently been designed to enable control over the zygoma implant's apical exit placement.
Guides for sinus augmentation with implant placement
Mandelaris and Rosenfeld were the first to create a roadmap for a complex sinus augmentation procedure. The intricacy of the fabrication process, as well as the several types of surgical guides, suggested for the lateral window opening, but particularly the proposed guides were initially severe shortcomings.
CAD/CAM surgical guides are readily available nowadays for sinus enlargement and implant implantation at the same time. Titanium screws were utilized to secure the guide in place for added stability. Although immobility was achieved during surgery, obstruction with the implant path, further bone removal from the screw, and the requirement for good bone quality remain its drawbacks. Furthermore, although it is recommended that the guide be removed when elevating the sinus floor, the inconvenience of withdrawing and adapting the guide during surgery is a serious setback. The tooth-borne surgical guide, on the other hand, provides better stability and convenience.
Chairside fabrication of guides
Implant drilling guides can be fabricated in a dental office using low-cost desktop 3D printers with great precision. The low-cost desktop 3D printer reduces the cost of previous commercial printers and software, eliminates laboratory and shipping costs, and may boost the usage of guided surgery. First and foremost, knowledge of additive manufacturing will be necessary, as well as some calibration of the implant planning and 3D printing software, as there are various areas where an error might occur. This technology has a lot of potential in dentistry, and it will only get better as time goes on.
The manufacturing technique for a chairside CAD-CAM radiological and surgical guide for dental implants has been published by several authors. When incompatibilities exist among manufacturers' digital systems, notably between CBCTs and chairside acquisition devices, this approach integrates the analog approach and CAD-CAM techniques for diagnosing and treatment planning implant-supported restorations. The process can be used in dental offices that already have a CEREC Omnicam AC intraoral scanner and an MCXL milling unit, as well as any CBCT scanner. To begin the suggested 2-mm osteotomy site, which necessitates an additional step, a stone cast or printed model is required to secure the milling guide.
Throughout the procedure, robotic technology allows for clear visibility of real-time physical and visual guidance and allows the surgeon to alter the plan dynamically. It is a computerized navigational system intended to help with both the planning and the surgical aspects of dental implant surgery. It uses haptic robotic technology to provide tactile guidance by constraining the drill's location, orientation, and depth. Actuators, which impart forces for touch feedback and controllers, enable haptics. The actuator moves in mechanical motion whenever an electrical stimulus is delivered. Electroactive polymers, piezoelectric, electrostatic, and subsonic audio wave surface actuation are among the newer generations of actuator technologies that have faster response times. This mechanical stimulation aids in the formation of virtual objects in a computer simulation, their control, and the enhancement of remote control of machinery and devices, delivering real-time visual and tactile information to the user. The surgeon maintains absolute control while using this assistive technology. This ensures accuracy and consistency without requiring the creation of a specialized plastic guide or the risk of executing an unguided freehand method.
| Conclusion|| |
Implant guides will continue to be an essential tool for accurate implant positioning and angulation. The guides are fabricated by any technique or material, the choice will solely depend on the clinician's individual opinions and prior experience. Implant placement with robotics seems to be a fascinating technique, but still, more clinical trials are needed to unravel its application in the field of implant dentistry.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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