There are countless aspects of full-arch surgery that are crucial to understand and perfect in order to perform this procedure at a high level. That being said, there are four critical AOX surgical skills that are always at the forefront of my mind during surgery. These are the aspects of the arch that I care most about optimizing.
1. Anterior-Posterior Spread
One of the principal roles of the full-arch surgeon is to optimize anterior-posterior spread. This is an effort to minimize both anterior and posterior cantilevers.
While anterior-posterior spread and the resultant cantilever are absolutely related, they are not the same thing. AP spread is the surgeon’s responsibility. The cantilever is the job of the restorative doctor.
That said, it is vital for the surgeon to maximize AP spread in order to limit the cantilever and improve the surgical outcome. It is my goal to maintain a Cantilever-to-AP spread ratio of less than 1 (CL/AP < 1).
In order to achieve this clinically, I attempt to have my anterior implants exit at the cingulum of the incisor region. Posteriorly, my goal is a second bicuspid position or better for a first molar prosthetic.
2. Torque
Achieving maximum torque at implant placement is critical for consistent success in full-arch surgery. Immediately loading a prosthetic with low torque values increases the risk of implant complications. Put simply, a low-torque, immediately loaded prosthetic is less resilient in the face of patient noncompliance or minor prosthetic malocclusion.
Most practitioners in the full-arch space will agree that a full-arch prosthetic can be successfully loaded with a composite torque of 120 N·cm or higher, and some articles have even reported lower values. Despite this, I consistently aim to achieve a target torque of 45 N·cm or greater per implant. This results in a composite torque goal of 180 N·cm or higher for each case I load.
If I cannot achieve this value through surgical means, I relay to the restorative doctor that I have some concerns on the surgical end regarding CTV. I request that the restorative provider attempt to eliminate any existing cantilever as much as feasibly possible via prosthetic means. I also ask that they pay extra close attention to a balanced occlusal relationship for that patient.
3. Screw Access Hole Position (SAH)
All too often, as surgeons, we don’t evaluate or even see the final prosthetic. At times, evaluating the prosthetic can be humbling. Seeing what our “perfect surgery” actually looks like on the prosthetic isn’t always cause for celebration.
Knowing where your access holes are is very important. Seeing and evaluating your final prosthetic is the best way to get instant feedback on this aspect of surgery. This is also the best way to ensure we are truly delivering a prosthetically driven surgery.
Being able to learn to control and perfect access hole position is the sign of an experienced surgeon.
During surgery, implant position and abutment angulation are at the forefront of my mind as I work to optimize and “drive” screw access hole positions where I want them in order to optimize the prosthetic. This is a constant intraoperative thought process and evaluation.
Screw access hole position is important for many reasons beyond just style points. The SAH position will affect the shape and size of the prosthetic, which are directly linked to both patient satisfaction and the patient’s ability to perform proper hygiene.
4. Closure
As I’ve said many times before, closure in full-arch surgery is highly undervalued. Taking time to perform an optimal closure with smooth, flat, well-approximated, and primarily closed tissue will yield a plethora of benefits in the long run. These include enhanced healing, improved final tissue position and contours, and ultimately better hygiene and peri-implant health.
While there are many, many areas of full-arch surgery that need attention, when I am operating, these four items are always at the forefront of my mind. I feel these are four of the most important things I can contribute to the surgery to help ensure its long-term success.