Implant Selection and the Use of Surgical Guides
Q&A with Dean E. Kois, DMD, MSD
Inside Dentistry interviews Dean E. Kois, DMD, MSD, an instructor at the Kois Center and a prosthodontist with a private practice limited to restorative, esthetic, and implant dentistry in Seattle, Washington
Inside Dentistry (ID): What implant design features are critical to a clinician's selection?
Dean E. Kois, DMD, MSD (DK): First, I believe that starting with excellent bone quantity and quality is the best implant design feature. Secondarily, abundant soft tissue is critical for achieving optimal patient outcomes. When we look at data for implant sites with voluminous healthy bone, it becomes more difficult to differentiate specific implant features that may improve outcomes. In general, I like to use implants that possess some degree of taper, have an aggressive thread pattern, offer platform switching, and feature surface modification all the way to the top of the implant.
ID: Are there certain patients who require certain types of implants?
DK: An implant that works well in patients whose oral health and bone is the most compromised is the one that I want to use for every patient. However, there is not one type that is perfect for all situations. Understanding a patient's risk factors, site anatomy, and available bone are more pertinent decision keys to selecting an appropriate implant type. For example, for immediate implant applications, I prefer more aggressive thread patterns to help achieve primary stability. I am also a proponent of shorter dental implants (ie, less than 10 mm). This allows me to minimize the need for vertical grafting procedures.
ID: Guided surgery is not as expensive as it once was, so why do you think there are still some clinicians who are not using it?
DK: I have made this jump in practice. I use a guided surgical protocol in 95% of my cases. Guided surgery is the only way to truly tie what you see on the computer from the cone-beam computed tomography (CBCT) scan to the mouth in an accurate way. But if asked why more clinicians haven't adopted a guided protocol, I think that it has less to do with cost and more to do with the fact that clinicians get comfortable with the way that they perform procedures and are concerned about burdening or changing an existing workflow. Implementing guided surgery requires extra steps and, potentially, another person in the practice to facilitate or carry out the workflow. This disruption is the barrier. Dentists are constantly told that they can print guides for only $20, but who is using the planning software, managing the printer, and finishing the guide? All of this takes time. In an already busy practice, this workflow is not easy to deploy. It takes time to train and time to execute. More importantly, it requires a desire and commitment from the clinician and team to create this model and build it in. When you are happy with your clinical outcomes, it can be difficult to see the need for change. Many clinicians have CBCT units and utilize them to visualize surgery but just don't take the extra step of creating a guide. For those who have adopted it, guided surgery is not foolproof either, and two major drawbacks are how it limits the clinician's ability to make corrections to angulation during surgery and that it is susceptible to inaccuracies if errant data is used to fabricate the guides.
ID: What design elements of the surgical guide are vital?
DK: From the initial scans to the design, all of the assets need to be accurate and precise. Movement during the CBCT scan is a very common way that errors in accuracy are introduced. To create more precise pathways for drilling and improve accuracy, I prefer to use the longest sleeves possible. The passive, fully seated fit of a surgical guide is vital as well. When possible, I extend mine by a few extra teeth to increase stability. Cutouts can help to confirm that the guide is fully seated at the cusp tips and permit better visualization of where the clinician is placing the dental implant. Access for irrigation is also important so that the clinician can control the heat generated by the drills at the surgical site.
ID: Now that so many pieces of the implant workflow can be accomplished digitally, does it ever make sense to use analog processes?
DK: For many years, I have been saying that you can do amazing things on the computer with planning, digital design, altered reality, and even artificial intelligence, but at some point, you have to turn to the chair, pick up your handpiece, and actually perform the procedure. In this regard, most of our analog principles are still in place, guiding the digital workflow.
Dean E. Kois, DMD, MSD