Consensus on Vertical for Oral Appliance Therapy
H. Ball DDS, D. Klauer DDS, D. Rawson DDS, L. Priemer DDS, T. Soileau DDS, S. Lamberg DDS, T. Morgan DMD, S. Carstensen DDS, D. Marangos DDS, E. Elliott DDS, J. Viviano DDS, K. Thornton DDS, D. Tache DDS
The newly formed LinkedIn Discussion Group, “SleepDisordersDentistry” had an open discussion on the impact of Vertical for oral appliance therapy. Here is a consensus for all to ponder.
What was asked,
“What I would like to see discussed here is the importance of vertical; some swear by it and others never vary vertical. Yet, everyone seems to have a similar success rate; or do they? I am sure there are some "Pearls" by those that vary vertical that could help those that don't vary vertical to help them understand when it is helpful. I started with this subject because there seems to be two sides on this issue and I think both sides could benefit by sharing their clinical experiences here.”
What was said,
The literature suggests that vertical should be kept to a minimum due to the potential for a negative impact on the airway caused by the jaw rotating back with increase in vertical (Cistuli). It was also pointed out that since the jaw opens and closes along an arc, if you increase vertical in some of the "fixed position appliances" you are actually increasing protrusion, and the benefit may actually be from an increase in protrusion rather than an increase in vertical. (H. Ball, S. Lamberg)
However, we also know that there remains an absence of good research on vertical. Anecdotal evidence shows this minimum concept to be flawed. Simply consider the different appliances available and how much vertical varies between them. If in fact, vertical should be kept to a minimum, how can it be that no research has demonstrated that appliances built to a minimum vertical afford superior outcomes?
So, lets hear the tips of clinicians that have done this a long time…
The Phonetic Bite:
This article will not be discussing any specific bite registration techniques. However, I want to point out that those that use the phonetic bite say that it allows the patient's own nervous system to tell us where the displaced parts of the cranio-mandibular system need to be placed for maximum muscular, and TMJ comfort, and maximum stabilization of the airway. Thus, it’s not about increasing or decreasing vertical, it’s about being at the right vertical. Typically, this bite results in less advancement and more vertical than the usual and customary approach of advancement. Clinicians on both sides of this fence need to have more discussion and comparison of their clinical experiences. Although I am a “usual and customary” clinician, my personal take on this is that there must be something to it as there are many respected clinicians using it successfully, and further investigation is clearly merited. Recently, Daniel Klauer and I retrospectively documented 20 consecutive cases, his completed with the Phonetic Bite and mine completed with my version of a George Gauge bite. We have not performed an official statistical analysis, as of yet, however, the AHI outcome results using both techniques are quite similar. How can this be that the Phonetic Bite resulted in a very similar outcome, even though the jaw was taken to a very different position? This begs further investigation and a full article. (D. Marangos, D. Klauer, D. Rawson, J. Viviano)
Keeping Vertical to a minimum:
Keeping vertical to a minimum and then increasing it when advancement alone does not do the trick was suggested. Some reported no meaningful improvement and others reported improvement for a subset of patients. Early on, when I made a lot of Silencers, I practiced this method. The Silencer does not allow for much vertical adjustment by the patient. In other words, the vertical is pretty well fixed with a couple of mms play. I liked the Silencer because it was easy to swap out the titanium pin for varying lengths, allowing me to easily increase vertical. Back then, if I had someone maximally advanced and outcome was short of optimum, I would open the bite and go from the standard 4 mm pin to a 6, 7, 8 or even 9 mm pin. My experience was that for some but not all patients, the outcome improved dramatically. So, for a subset of patients, increasing the vertical did seem to help. However, since moving to appliances that allow the patient to establish their own preferred vertical, such as the Dorsal, Herbst, Narval, D-SAD, etc., I have not been so concerned about varying vertical as much. The theory being, vertical matters only in appliances that restrict the patient to a particular vertical, if an appliance lets the patient actually gravitate to and find their “vertical sweet spot", it negates the need for us to be concerned with vertical. So, start with minimum vertical and let the patient open to the vertical that best suits their airways needs. Think about the child sick with a cold, and the extended neck posture they gravitate to without any aid to establish a better airway, I'm wondering if this applies here. Of course, things aren’t always that simple. Don Frantz published a case study many years ago where he demonstrated that when an EMA appliance was remade at a smaller vertical for a patient, it was no longer effective. Don remade it at the original vertical, and it became effective again. In my theory, one would not expect this to happen with an EMA which does not restrict the vertical to a set position, however, perhaps the action of the elastics holding the two components together actually reduces the patients ability to vary vertical themselves, the action of the elastics pulling up and forward may place this appliance in the same category as the Silencer and Klearway, rather than the Dorsal and Herbst. Of course, one more concern is REM sleep, apnea is often worse during REM sleep due to loss of muscle tone and it is not clear if the mandible would need vertical support to maintain the position it gravitates to during NON-REM sleep. All just a theory! (E. Elliott, L. Priemer, J. Viviano)
The notion of utilizing an in-office physiotherapist at the initial appointments was discussed. The theory being that the resulting muscle relaxation allows the patient to tolerate more advancement affording a good outcome without vertical opening. (T. Soileau)
“Comfort is King” was thrown into the discussion. Which of course, is of paramount importance. After all, “high compliance” is what makes us competitive with a therapy that is clearly more effective (CPAP). So, we must nurture and preserve that advantage. That the Cistuli study demonstrated patients prefer minimum vertical was also discussed. However, that study did not truly assess patient preference in a fair manner. Opening the vertical by 10 mm at maximum protrusion does not really give us a clear understanding of either patient preference regarding vertical, or the impact of vertical on outcomes. Finally, The notion that an increased vertical may benefit patients that have a poor nasal patency was introduced. (S. Lamberg, T. Morgan)
Gender differences were also discussed. Larger vertical opening is required for men and smaller for women. Post-menopausal women also seem to benefit from a greater vertical. The range of vertical variance that was suggested is a 4-9 mm change from the baseline appliance, not the drastic 10 mm increase discussed in the Cistuli study. Todd Morgan explained how he first came to this realization while doing research using the Tap II and then switching midstream to the TAP III; which was found to have less vertical opening due to its design. There was also the suggestion that obesity played a role, in that an obese male could benefit from an increase in vertical. However, Dan Tache mentioned that perhaps there was an exception to this “rule”, females diagnosed with Polycystic Ovarian Syndrome (PCOS) are likely to have secondary male characteristics including a smaller airway due to the deposition of additional para-pharyngeal adipose tissue. When advancement alone is not sufficiently improving airway stability for PCOS patients, incrementally adding vertical may improve outcomes. Dan stressed that varying vertical can be tricky and that it should be increased in small increments. (T. Morgan, K. Thornton, D. Tache)
Steve Carstensen introduced a phrase he once heard from Todd Morgan, it is about “the size of the box the tongue comes in”. He suggested that the underdeveloped maxillae prevents proper tongue position; so increasing the vertical for these individuals in part makes up for the deficient Maxillae by increasing inter-occlusal space, in essence, making more room for the “Tongue in the Box”. Steve rarely increases vertical for individuals with big, wide maxillae, but routinely for those with narrow, tall Maxillae. He also suggested not filling in the resulting space on the appliance so the tongue has space to spread sideways between the arches. It’s all about making more room for the “tongue in the box”, by raising the lid and pushing out the walls. Dennis Marangos added that for deep bites, the vertical may be opened 9-10 mm just to clear the occlusion. If the vertical of a normal bite is increased to the same degree it may be too much and impact negatively on the airway. He mentions considering the Shimbashi measurement when increasing vertical, which is CEJ of 11 to CEJ of 41. Erin Elliott shared with us that patients with high mandibular plane angles should probably have minimum vertical. Opening them up rotates the jaw down and back, potentially compromising the airway. Finally, in the example above regarding the EMA, Don Frantz speculated that patients with a long soft palate could benefit from an increase in vertical. (T. Morgan, S. Carstensen, D. Marangos, E. Elliott, J. Viviano)
A heartfelt thanks to all that participated in this discussion. Although one should consider this a working document, I believe that this consensus on vertical will go a long way in guiding those clinicians beginning in this field and also present some valuable insights to those of us that have been at it a while. I look forward to future discussions on our SleepDisordersDentistry LinkedIn group!
John Viviano DDS D ABDSM