Doing It Right the First Time: A Look at Implant Surgical Guides

By Michal Christine Escobar

The use of implant surgical guides in dentistry is a crucial topic that impacts the precision and efficiency of implant procedures. When made and used correctly, these guides can offer remarkable accuracy in determining optimal positions and angles for implant placement. If a dentist who places implants decides to use a surgical guide, he or she must answer many questions: What type of guide should be used? Should it be made in-house or ordered from a lab? Should freehand implant placement be considered instead of a guide? Overall, understanding the nuances of implant surgical guides is paramount for dentists aiming to deliver precise, efficient and patient-centric implant treatments.

Advantages: Precision, Comfort, Revenue Boost

An implant surgical guide is a custom-made acrylic resin piece designed to fit snugly over adjacent teeth or completely on an edentulous ridge, featuring a precise hole indicating the implant’s intended location.(1) These guides offer dentists numerous benefits. For instance, dental implant sites might be difficult to see or access, which could lead to incorrect placement. However, an implant surgical guide allows for “maximum precision and accuracy.”(1) Similarly, surgical guides make future restorative complications less likely.(2) Surgical guides contribute to more comfortable and faster surgeries, which mean less-invasive procedures and fewer follow-up appointments.(1) Surgical guides also offer an additional revenue stream. Using CDT Code D6190, Radiographic/surgical implant index, the average cost to the patient is about $300.(2) However, the cost to the dentist is closer to $200 (if made in a lab) or $20 if made in-house.(2)

Drawbacks: Visibility, Over-Reliance, Fabrication Time

Some drawbacks exist when using implant surgical guides. “Visibility is more difficult, so you need to be very sure they are seated correctly and anchored well,” said Ross Isbell, DMD, MBA, AGD Impact Testing the Tools columnist. “There is also a risk that there is too much trust in the guide and that the user doesn’t do as much to confirm placement and angulation of the drills or implants throughout the process.”

Isbell said appropriate radiography can prevent complications in reconstruction or failure of the implant.

“Guides are only as good as the person who designs them and the preparation and accuracy of the materials provided to the fabricator,” said Timothy F. Kosinski, DDS, MAGD, AGD editor. Understanding the final prosthetic fabrication is also very important. “Depending on the design selected — full-arch implantretained prostheses versus implant-retained overdentures — there needs to be a specific interocclusal space. Not realizing this fact can make fabrication challenging or impossible for the dental lab. Surgical guides have come a long way in helping dentists feel more confident in proper implant placement, but they are not a panacea, and practitioners need to be in control of the process,” he said.

When using surgical guides, drilling on a slope or against a hard plate could deflect drills without the dentist realizing it.(2) Since successful implant surgery is dependent on the use of cool saline and not overheating the bone, dentists should be highly aware of the fact that guides get in the way of copious irrigation.(2)

And, of course, surgical guides require fabrication time, notes Eric G. Jackson, DDS, MAGD, FICOI, FASD, FICD, FADI, FPFA. This means gathering records, taking radiographs and creating a design, in addition to the actual production of the guide.

“You can’t create a guide on the fly, so that’s a major reason why not every single case can or should have a surgical guide,” said Jackson.

Surgical Guide Varieties: Supports and Types

Implant surgical guides are essential for surgeons seeking precise guidance on drilling osteotomies and thus preparing the bone for implant placement.(1) Utilizing digital impressions or imagery, the guide creates remarkable accuracy in determining the optimal position and angle for the dental implant procedure.(1)

While the benefits of surgical guides are abundant, a “clear, universally accepted classification” of these guides does not exist.(3) However, D. Salem, a dental/oral and maxillofacial prosthodontist with a private practice in Brisbane, Australia, performed an extensive literature review in the Journal of Dentistry and Oral Health and proposed a new classification for surgical guides. The new classification would allow for three types of surgical guides: a free guide, an access guide and a precision guide.(3)

"The 'free guide' would be to show where the tooth center point is. The 'access guide' would guide the first drill only; whereas the 'precision guide' would guide the whole drilling sequence. Once the restoring practitioner decides on the type of guide, then the support during the surgical phase comes next. This will depend on the dentition and required stability and accuracy of the guide. There are four possibilities there, namely: tooth supported, [soft] tissue supported, both tooth and [soft] tissue supported, or [soft] tissue supported with an accessory fixation for edentulous cases. To cover for some of the designs that currently exist, the access and precision guides can have fixed guidance or removable guidance where the guiding mechanism can be removed."(3)

Until clearer classification systems are universally accepted, it may be simpler for dentists to use the familiar terms: pilot, guided and fully guided.

A pilot guide offers dentists comprehensive guidance for positioning, angle and depth during dental procedures.(2) These guides usually feature a 2.0 sleeve size, enabling dentists to insert their pilot drill through the sleeve for precise drilling.(2) After ensuring the correct position, angle and depth, the initial drill is made, and then the guide is set aside, allowing the dentist to complete the osteotomy according to their preferred technique.(2) According to Kosinski, these guides must sit completely properly without any rocking, and they are especially beneficial when implants need to be parallel or nearly parallel.

Guided implant surgical guides provide precise positioning, angle and depth information. These guides feature larger sleeves, allowing dentists to utilize drills of different widths and achieve complete angulation throughout the entire osteotomy procedure.(2) While these guides are particularly effective for creating parallel bridges and adjacent implants, they do have limitations. For instance, the thicker sleeve width of 7 millimeters may not be suitable for all spaces, and some patients may find it challenging to accommodate drills of varying widths up to 24 mm in their mouths.(2) Additionally, these guides can be more costly to design and may necessitate a separate guided drill kit.(2)

With fully guided drilling, everything is done through the guide, including the implant placement itself.(2) These guides “constrain the pilot drill, osteotomy drills, implant placement and depth [… and] often present the least risk of knockout errors or implants shifting during placement due to the redundancy of physical constraints they provide throughout the entire placement procedure.”(4) According to Kosinski, proper and complete positioning of these guides should always be evaluated before the patient is excused because a small error in the posterior placement can result in a major error in the anterior.

Stackable guides are a type of fully guided implant surgical guide comprised of several removable layers that can be stacked on top of each other to “provide greater accuracy and precision during implant placement than traditional surgical guides.”(5) These guides streamline surgical procedures by eliminating the need for repeated guide adjustments during surgery. This not only reduces surgical time but also mitigates the risk of complications, ultimately improving patient outcomes. Stackable guides are well-suited for a broad spectrum of implant procedures, encompassing single, multiple and complex cases.(5)

Each guide also requires some form of support to ensure the accuracy and stability of the surgical guide.(2) There are three main types of support: tooth-borne, soft tissue–borne and bone-borne, each serving specific needs in fully guided procedures.(2)

Tooth-borne support is considered the most predictable, as it utilizes the patient’s own stable hard tissue and at least three to four healthy stable teeth (that are not in the implant site’s way) to support the guide securely.(2)

Soft tissue–borne support is often used for edentulous patients or those with severely compromised teeth. This support type is beneficial for cases not requiring alveoloplasty.(2)

Bone-borne support is more complex, involving bone segmentation based on precise cone beam computed tomography (CBCT) renderings of the patient’s jawbone. This support type may require significant flap elevation and is suitable for dentists experienced in larger surgeries. However, it offers an exceptionally close fit for the surgical guide after alveoloplasty, allowing for precise implant placement.(2)

Essential Equipment for Creating Surgical Guides

To create an implant surgical guide, dentists start by taking a CBCT scan to assess the patient’s oral structure. For initial scans, a full field of view is recommended to detect any potential issues. Next, dentists use an intraoral scanner to generate a digital STL file, which is then imported into specialized software for guide creation.(2) This software overlays the STL file onto a 3D model of the patient’s jaw, improving accuracy for intraoral visualization. Using this model, dentists devise a treatment plan based on anatomical considerations and nerve mapping.(2) Then, a meticulous wax-up is necessary. The wax-up is crucial for adjacent implants or multitooth spans, ensuring proper spacing and alignment. Dentists also cross-check CBCT data and 2D radiographs to avoid biological conflicts and confirm optimal buccolingual and mesiodistal dimensions. Finally, the guide is designed to fit snugly over the STL model, ready for 3D printing or fabrication by a dental lab.(2)

Clinical Choices: Lab vs. In-House Methods

When dentists do decide to create an implant surgical guide, they must decide if they’ll have a dental lab fabricate it or if they’ll make it in-house. Before choosing, they need to consider a few important factors. A lab-created guide will generally take more time to create and will cost much more, especially if the lab is asked to both design and manufacture it, according to Isbell. If the dentist designs the guide, however, the price of manufacturing will be cheaper.

The higher price tag for lab-created guides also means the guide will be created by experienced technicians, Jackson says. For dentists who design their own guides, the technicians may even offer some advice on how to improve specific designs and tips on how to create better designs in the future.

“I’m a big proponent of dental labs,” Jackson said. “Even though we’re trending toward making everything in-house, it’s important to keep in mind that the quality of those in-house guides will be very dependent on the practitioner’s experience, which could be very limited.”

Kosinski noted that, before choosing to make surgical guides in-house, dentists should keep in mind that “training and experience are needed to fabricate proper surgical guides. As with any dental procedure, practice makes perfect, but any discrepancies in fabrication could be disastrous. Therefore, it is critical that the dentist both feels confident and is competent in design and fabrication. There can be no errors in fabrication.”

Dentists who are willing to create guides in-office — and make the investment either in a 3D printer and the resin the printer requires or in software and mills — will find that the price per guide will be significantly cheaper compared with a lab-created one, and fabrication time will be much faster as well, Kosinski says. However, before making the investment, Kosinski cautions dentists to first evaluate how many guided surgical procedures they perform on a regular basis to determine if there will be a true return on investment.

Embracing Flexibility: The Benefits of Freehand Implants

While implant surgical guides are highly valuable tools for the dental community, freehand placement of dental implants remains a viable option. For example, freehand placement allows the practitioner to diagnose, plan and place implants without having to wait for a guide to be fabricated — which is highly valuable in an emergency situation, Kosinski notes.

“Implants have been placed by skilled clinicians for a very long time without a guide,” Jackson said. “Not every case is so complicated as to need a guide. Plus, when you use a guide, you’re asking a patient to spend more time and money — you’re driving up the cost of care. So, dentists should be judicious.”

Michal Christine Escobar is a freelance writer based in Chicago. To comment on this article, email impact@agd.org.

References

1. “Implant Surgical Guide — How to Create Them with the Use of Dental Software.” 3Shape, 3shape.com/en-us/digital-dentistry/dental-software/implant-surgical-guide. Accessed 26 April 2024.

2. Vorholt, Steven. “The 3 Types of Surgical Guides [And How to Make Them In-House].” YouTube, uploaded by Henry Schein Dental, 17 Nov. 2023, youtube.com/watch?v=KlkVSFvD8EU.

3. Salem, D. “Surgical Guides for Dental Implants; A Suggested New Classification.” Journal of Dentistry and Oral Health, vol. 6, 2019, pp. 1-8.

4. Stanley, Robert. “A Comprehensive Classification System for Dental Implant Surgical Guides.” Dentistry Today, 12 April 2022, dentistrytoday.com/comprehensive-classification-system-for-dental-implant-surgical-guides.

5. “Stackable Surgical Guides: The Next Generation of Implant Placement.” Let’s Talk Guided, letstalkguided. com/2023/10/11/stackable-surgical-guides-the-next-generation-of-implant-placement. Accessed 13 May 2024.