Imagine committing three years of your life and money to learn fine occlusion, then be told you are going to mess it all up in some patients.
That was me 10 years ago as a first year Prosthodontic resident who had just been introduced to the use of Mandibular Repositioning Devices (MRDs) to treat Sleep Disordered Breathing (SDB) conditions. I was informed by my dental sleep mentors that in certain patients these devices, with prolonged wear, can cause permanent tooth movement and/or occlusal changes. I also discovered there was evidence in the literature of occlusal changes occurring in some patients with the use of MRDs.1, 2
This fact still does not sit well with me 10 years and many hundreds of satisfied sleep patients later. What is different now is that I have witnessed the profound positive effect that successful treatment of SDB with MRDs has on the quality and quantity of my patients’ lives. I also have learned how few alternative treatment options SDB patients have and how for many a MRD is the only tolerable option. I understand also that the main alternative treatments options, CPAP and Orthognathic surgery, also have significant potential side effects.
During the past several years some of my patients have experienced dental related side effects resulting from long term wear of their MRD. They represent a small percentage of the overall number of patients. Dental changes resulting from prolonged MRD wear described in the literature include reduction in overbite, reduction in over jet, decrease in mandibular crowding, development of an anterior cross bite and development of a posterior open bite.1 The most common change I have observed is what I call “anteriorization of the mandible”. After wearing the MRD all night, some patients find it difficult to get the mandible into its normal position where the teeth meet in maximum intercuspation. They feel the anterior teeth with increased contact and the posterior teeth not touching at all. Many patients experience this temporarily on removal of the appliance; for most it either resolves spontaneously or with the help of biting with a repositioner device in place. In a small number of users, this occlusal change can quickly become permanent.
It is interesting that the majority of my patients with permanent occlusal changes do not notice or report these changes but rather I have identified the change at a follow up appointment. Nearly everyone to whom I have pointed out this side effect has fortunately responded that they remember reading and me discussing with them that risk as part of the informed consent process prior to treatment. I feel this is because I do not shy away from addressing this potential problem up front and laying it out clearly in my written consent forms.
After identifying an occlusion change what follows in my office is an important conversation between the patient and I in which we again discuss the risks versus benefits of MRD therapy. I always start this conversation by revisiting the patient’s original chief complaint or diagnosis and compare that their current status, both how they feel (subjectively) and what results the various follow up sleep tests with the appliance in place showed (objectively). We also revisit the alternative treatments that could possibly treat the patient as well as the appliance. In my experience my patients are better at weighing up the dental side effects risks versus social and health benefits than I am. I, like many other sleep dentists I talk to, are over concerned or too focused on the dental changes because it seems to fly in the face of our dental education and ethics. Our patients often rank the ability to breathe when they are asleep as more important than a perfect occlusion. As one of my mentors Dr. Keith Thornton has said “Breathing trumps eating every time”.
Of course some of these patients want to know how their occlusion can be returned to normal. There are several options available depending on the individual patient’s situation including jaw exercises, physical therapy or manipulation, equilibration/adjustment of the teeth, placement of fixed restorations to reestablish occlusion or orthodontics. Each of these solutions could warrant an essay to discuss but I will focus here on the Orthodontic solution because in my experience it is the most appropriate solution for many of my patients. When I present this option invariably the patient’s first questions are “can I wear my oral appliance when I have the braces on and what about after the braces are removed?” This is a very important question for the patient. After experiencing the social and health benefits of treatment of their SDB condition, most are very reluctant to give it up.
In the past my short answer to that question has been no, for two reasons: First, during orthodontic treatment braces on the teeth prevent the OA from fitting, and second, when the occlusion is corrected and braces removed it is advisable not to resume wearing a MRD because of the risk of further occlusal changes. I suggest CPAP would be the alternative treatment. When given these choices, so far none of my sleep patients have pursued braces and have rather continued to wear their MRDs and accepted the occlusal change. However more recently there have been several reports from dentists of using MRD therapy during Invisalign therapy. This could certainly help during the orthodontic treatment phase but long term I would still be concerned that use of the MRD could lead to unstable occlusion.
As in all fields of medicine prevention is better than cure. So can we prevent these dental side effects from occurring in all of our patients? Over the years dentists have used a number of techniques to help patients maintain their occlusion. These techniques are typically used after the MRD is removed and include biting with a repositioning device in place, chewing gum or stretching exercises. Research studies have shown the effectiveness of these techniques short term but not long term.3, 4, 5 A recent study also shows that occlusal changes can be progressive with long term wear of a MRD.1 Future research will hopefully give us more guidance on how to prevent occlusal changes and maybe also answer whether appliance design has an effect on dental side effects and if there are patient factors that make them more susceptible to these occlusal changes.
The two techniques I currently instruct all my MRD patients to use are a morning repositioning device every day and chewing gum when necessary. The device my patients use is the AM Aligner from Airway Management. I like that it is simple to make and simple for the patient to use. I instruct the patients to insert the AM Aligner every morning after removing the MRD and bite firmly on it until they can see in the mirror their anterior teeth fitting perfectly in to the indentations on the device. I also explain that if the teeth are not perfectly fitting they must continue to bite on the device until they are. If they cannot achieve that I ask them to contact my office because that means their occlusion is starting to change. Anecdotally my patients who have experienced occlusal changes nearly all confess to not using the AM Aligner every morning. However I also have a quite a number of patients who freely admit to never using the AM Aligner and their occlusion has experienced no changes. A statement I make to all new patients on the use of the AM Aligner is “Your new MRD has the ability to act like an orthodontic device and move your teeth or change your bite. You must use the AM Aligner every morning to reverse the orthodontic effect”. I also instruct patients to chew gum (sugar free of course!)if they are having difficulty getting their teeth to fully fit into the indentations on the AM Aligner or if their bite feels off or unusual anytime during the day after wearing their MRD.
Every month that goes by the body of evidence confirming the effectiveness of MRDs in alleviating SDB continues to grow. This evidence coupled with the high incidence of SDB, poor compliance with CPAP and increasing awareness among patients and physicians of MRDs means there is going to be increasing demand for MRD therapy. As dentists we are the only professionals who can provide this valuable therapy.
However no matter where I speak to dentists on this topic at meetings and study clubs around the country the risk of occlusal changes is the “elephant in the room”, one of the main reasons dentists are reluctant to provide this service to patients. As Dr. Alan Lowe has said publically many times, we as dentists have to “get over it!” The risk of occlusal change is real and should not be down played. We must be clear in explaining that risk to our new patients and clearly describe the risk in our written informed consents. That way a patient who finds that risk unacceptable can consider alternative therapies. We should use MRDs whose design we feel minimizes the chance of these occlusal changes and instruct our patients in techniques to try and prevent them occurring. If changes do occur we must help our patients decide if their social and health concerns regarding SDB outweigh their dental concerns and advise them on procedures that could correct the occlusal changes if that is desired. That way we as dentists can continue to provide a life changing and often lifesaving treatment while doing our best to inform and protect our patients from adverse dental side effects.
REFERENCES
Pliska BT, Nam H, Chen H, Lowe AA, Almeida FR, authors. Obstructive sleep apnea and mandibular advancement splints: occlusal effects and progression of changes associated with a decade of treatment. J Clin Sleep Med. 2014; 10:1285–91.
Marklund M, Franklin KA, Persson M, authors. Orthodontic side-effects of mandibular advancement devices during treatment of snoring and sleep apnea. Eur J Orthod. 2001; 23:135–44.
Marklund M, Legrell PE, authors. An orthodontic oral appliance. Angle Orthod. 2010; 80:1116–21.
Ueda H, Almeida FR, Chen H, Lowe AA, authors. Effect of 2 jaw exercises on occlusal function in patients with obstructive sleep apnea during oral appliance therapy: a randomized controlled trial. Am J Orthod Dentofacial Orthop. 2009; 135:430.
Cunali PA, Almeida FR, Santos CD, et al., authors. Mandibular exercises improve mandibular advancement device therapy for obstructive sleep apnea. Sleep Breath. 2011; 15:717–27.