| Klearway™
Snoring and Obstructive Sleep Apnea Appliance Technical Notes by Alan A. Lowe, DMD, PhD, FRCD(C), FACD |
1. Overview
Approximately 50 million people across North America annually report some type of sleep problem to their physician. It has been estimated that nine percent of women and 24 percent of men aged 30 to 60 have some degree of Obstructive Sleep Apnea (OSA) - a total of 20 million people. Due to increasing media coverage of this problem, the public is quickly becoming aware that OSA can be a serious problem requiring medical attention. As our population ages and the problems of OSA and snoring become more prevalent, dentists will inevitably be asked more frequently about the use of oral appliances for the treatment of snoring and OSA. Oral appliances have been found to be effective in treating snoring and mild OSA and in moderate to severe OSA patients where nasal Continuous Positive Airway Pressure (nCPAP) or uvula surgery have proven unsuccessful. More than 3,000 Klearway™ appliances have already been used worldwide.
2. Snoring and Obstructive Sleep Apnea - Definitions
(a) Obstructive Sleep Apnea (OSA)
OSA is a disorder of the upper respiratory tract in which the tongue is sucked back against the posterior wall of the pharynx by the negative pressure of inhalation. If the obstruction remains in place for more than 10 seconds and occurs more than five times per hour, the patient will usually suffer the symptoms of sleep deprivation the following day.
In severe cases, this condition can be life-threatening. Hypoxia (chronically low levels of oxygen during sleep) may eventually harm the cardiovascular system. OSA may also be responsible for hypertension, stroke and heart attacks.
(b) Upper Airway Resistance Syndrome (UARS)
A recently described condition of poor sleep and sleepiness related to snoring and partial upper airway obstruction without apneas or hypopneas that is improved with relief of the obstruction.
(c) Snoring
Snoring occurs when the tongue is posteriorly displaced but does not contact the posterior pharyngeal wall. This narrows the airway and causes air to move rapidly through the passages, causing the vibrations of snoring. While snoring may not be life-threatening, it is still a significant concern for the sufferer and his or her bed partner.
(d) Apnea
No breathing (absence of airflow at nose and mouth) for no less than 10 seconds.
(e) Hypopnea
An abnormal reduction in breathing for no less than 10 seconds.
(f) Apnea Index (AI)
The number of apneas per hour of sleep. Normal is no more than five.
(g) Apnea-Hypopnea Index (AHI)
The number of apneas and hypopneas per hour of sleep. Normal is controversial but often considered no more than 10.
(h) Respiratory Disturbance Index (RDI)
The number of apneas and hypopneas per hour of sleep (the same as AHI, including normal values).
(i) REM Sleep
REM equals rapid eye movements, a marker of a phase of sleep associated with dreams, maximal muscle relaxation, shallow breathing and, with other factors such as obesity, oxygen desaturation.
(j) Sleep Fragmentation
Sleep that is repeatedly disrupted by arousals, often related to respiratory events.
(k) Oxygen Saturation (SaO2)
A measure of arterial oxygenation in the body. Assuming normal blood flow hemoglobin concentration, SaO2 indicates the amount of oxygen available to the body. Normal is >95% at sea level and >90% during sleep.
(l) CPAP
Stands for Continuous Positive Airway Pressure, a major treatment for OSA.
(m) UPPP
Stands for uvulopalatopharyngoplasty, a commonly performed surgical operation on the soft palate and pharynx to relieve snoring and OSA.
(n) LAUP
Stands for Laser-Assisted Uvulo-Palatoplasty, a recently introduced technique similar to UPPP but capable of being performed in an office.
3. The Klearway™ Appliance
The Klearway™ adjustable mandibular advancement appliance was developed in by Alan Lowe, DMD, PhD, FRCD(C), FACD, Professor and Chair of the Division of Orthodontics at the University of British Columbia’s Faculty of Dentistry. Available in Canada exclusively through Space Maintainers Laboratories Canada Ltd., patents have been obtained by the University of British Columbia both across North America and worldwide. It offers several distinct advantages over other appliances currently available on the market. The Klearway™ works by keeping the teeth together and holding the lower jaw and tongue forward during sleep to open the airway.
A Clinically Proven Answer
To date, more than 3,000 patients worldwide have already benefited from the use of a Klearway™ appliance. Klearway™ is the most thoroughly field tested and researched oral appliance for the treatment of snoring and OSA available.
Progressive titration capabilities together with excellent compliance give Klearway™ the highest reported treatment success of any oral appliance used for the treatment of snoring and OSA:
Successfully treats snoring and 80% of mild to moderate OSA patients.
Successfully treats snoring and 61% of severe OSA patients.
Increases airway size in OSA patients particularly at the level of the velopharynx.
Covert compliance monitoring shows that Klearway™ is worn on average 6.8 hours per night.
Can be used to reduce vertical jaw posture which is significantly higher in OSA patients.
Extensive multi-centre clinical trial, funded by the Canadian government through the National Centres of Excellence Program (Inspiraplex) has compared the effectiveness of Klearway™ and nasal CPAP.
The Klearway™ appliance has been shown to effectively increase airway size during sleep, to be worn consistently throughout the night and to have a significant impact on both snoring and OSA.
Fully Adjustable
Klearway™ facilitates the very slow and gradual forward movement of the mandible by permitting the patient to adjust the appliance to his or her own comfort level with the guidance of the attending dentist. A total of 44 forward positions are available in increments of 0.25 mm covering a full 11.0 mm range of anterior/posterior movement. Such small increments help avoid rapid jaw movements that can cause significant discomfort. It also allows the patient to feel less restricted and thus less claustrophobic (a sensation experienced by a small number of patients during the first few nights of wear).
Lateral and vertical jaw movements are permitted enabling the patient to yawn, cough, swallow and drink water without dislodging the appliance. Bruxism and TMJ patients are also very comfortable since Klearway™ may reduce the complex jaw movements that can occur during interrupted sleep.
Superior Fit and Retention
Fabricated of thermoactive acrylic, the appliance is warmed under hot water becoming pliable for easy insertion. The acrylic resin hardens as it cools to body temperature, providing full coverage of and affixing itself firmly to both arches. This supplies excellent retention characteristics designed to keep the appliance in the mouth.
Extremely Comfortable
The thermoactive acrylic significantly decreases soft tissue and tooth discomfort. Each appliance is carefully designed not to encroach on tongue space.
Easy to Prescribe
A stone model of both arches from impressions must accompany the prescription sent to Space Maintainers Laboratories Canada Ltd. A bite registration should also be taken and included (should represent 2/3 of the distance from the centric occlusion to full protrusion with a 2 mm incisal vertical opening). An accurate bite registration is critical in fabricating an appliance which will not impair the teeth, soft tissues or TMJ/occlusion.
Since added retention for the Klearway™ appliance may depend on the Adams clasps in the lower arch, the patient should have at least one clinically sound posterior tooth in each lower quadrant. In addition, the patient should be able to protrude the mandible forward with no restrictions in jaw movement.
D. A Medical/Dental Team Effort
As snoring and Obstructive Sleep Apnea are medical disorders, the dentist’s role is adjunctive. Prior to treatment with an oral appliance, the patient must be assessed by the attending physician and/or sleep specialist. The physician may require an overnight polysomnogram to diagnose the sleep disorder and to provide the dentist with a written referral or prescription and diagnostic report.
Because of the obvious life-threatening implications of sleep disorders, it is imperative that treatment to stop snoring commence only after the potential presence of other associated medical conditions, including sleep apnea, is ascertained. Combination therapy with other treatments such as weight loss, surgery and CPAP may be indicated for some patients and must be co-ordinated with the attending physician.
The practitioner involved in oral appliance therapy must have adequate training in procedures so they:
understand the biological basis between oral appliances, respiration, snoring and obstructive sleep apnea.
understand anatomical considerations and limitations in relation to sleep apnea.
understand current diagnostic and polysomnographic procedures available for the assessment of snoring and sleep apnea.
are able to recognize and identify local and systemic conditions that may influence the results and appropriateness of oral appliance treatment including the anticipated behavioural response to treatment.
It is important that dentists interact with medical specialists with extensive training in sleep disorders medicine who are directly affiliated with accredited sleep centres. Overnight clinical polysomnography may be required for the accurate diagnosis of OSA. Polysomnography involves the simultaneous recording of a number of physiological variables during sleep. This allows for the accurate assessment of sleep apnea, periodic limb movement disorders, narcolepsy, parasomnias and other major sleep disorders.
E. Adding Sleep Therapy To Your Practice
Becoming involved with the treatment of snoring and OSA can be a very exciting and rewarding part of any dental practice. To effectively change the quality of someone’s life with an oral appliance can significantly alter a practitioner’s perspective on health care delivery.
Any dentist with an interest and a minimal amount of training in the field who has established a working relationship with a local sleep centre can begin to provide effective therapy for a large group of patients with snoring and OSA. An international group of dentists with a particular expertise in this area called the Sleep Disorders Dental Society provides a newsletter, an annual meeting, a slide/manual guide, a library for member dentists and a Resource Centre for both patients and dentists (Telephone 412-935-0836).
FREE Patient Presentation Brochures Available from Space Maintainers Laboratories Canada Ltd.
Developed specifically for use as a patient education and promotional tool.
Outlines rationale for use by patients.
Answers the most commonly asked questions regarding snoring, OSA and Oral Appliance Therapy.
Available FREE OF CHARGE* in separate 25 brochure packages for use in waiting room or during case presentation.
* Offer void in Ontario due to the regulations of the College of Dental Technologists of Ontario.
F. Summary Therapy Sequence
|
Clinical Protocol for Oral Appliance Therapy |
The following therapy is suggested by the Sleep Disorders Dental Society (SDDS) for the management of the selection and use of oral appliances in patients who are being treated for snoring, OSA and related sleep disorder breathing disorders.
Medical assessment by attending physician or sleep specialist.
Written referral / prescription / diagnostic report sent to dentist.
Dental Examination including:
Refer patient back to attending physician or sleep disorders specialist for assessment.
Possible modification, redesign or remake of appliance as required.
Recall appointments and maintenance as requested by patient and/or physician.
G. Detailed Therapy Sequence
Prior to the treatment of either snoring or OSA with any oral appliance, a complete assessment by the patient’s physician and/or sleep disorder specialist is very important.
(a) Initial Examination and Record Taking
Oral assessment essential to ensure the patient has a healthy mouth, sound teeth in each arch and that unrestricted forward jaw movement is possible.
A stone model of both arches from impressions is submitted to the laboratory together with a bite registration taken at two-thirds the distance from centric occlusion to full protrusion.
For the best accuracy, a George gauge with a grey 2.0 mm fork should be used for the bite registration.
Two teeth (first bicuspids and molars unless otherwise requested) in the lower arch are selected for the placement of ball and/or Adam’s clasps in the event that added retention may be needed later in treatment.
Notes and Concerns:
Patients with mild TMJ discomfort and/or bruxism can usually wear Klearway™ with ease since the jaw position used is very comfortable for both the TMJ and the dentition over the long term.
Totally edentulous patients may not be ideally suited for treatment with mandibular repositioners since they may not have enough intraoral retention to keep the appliance in the mouth during sleep.
Patients with edentulous maxillary arches and adequate teeth in the lower arch may respond favourably to Klearway™ therapy.
For the limited number of patients with atypical jaw movements, optional soldered balls can be placed at the ends of the distal expansion screw arms to ensure the upper and lower arches remain connected.
(b) Insertion Appointment
After showing the patient their custom-made appliance, describe all the possible limitations and side effects of this form of therapy.
Have the patient read and sign an Informed Consent form and answer any questions before inserting the appliance.
Verify the clasp locations and record the opening of the expansion screw with a Boley gauge.
Instruct The Patient Regarding The Proper Method of Inserting The Appliance.
Warm the appliance by submerging it in a container of hot tap water or by holding it under running hot water (only as hot as their fingers can comfortably tolerate).
Instruct the patient not to heat the appliance by any other means as they may irreversibly damage it.
While observing their teeth in the mirror, have the patient insert the appliance into the mouth and press the upper rim up onto the upper back teeth.
Once fully seated on the upper teeth, have the patient close the lower teeth forward into the lower portion of the appliance and bite firmly.
When the appliance is fully seated, the patient will be able to confirm visually (with the mirror) that each tooth is in the correct position on the appliance.
If the appliance does not seat properly, re-heat the appliance and working models in hot water, fully seat the appliance on both casts, remove the appliance with care not to distort it and reinsert in the mouth.
Instruct The Patient Regarding The Proper Method of Removing The Appliance.
Rinsing the mouth with warm water will soften the appliance and make it easier to remove.
Instruct the patient to grasp the edges of the upper back portion and pull down (NOT forward). This will dislodge the appliance from the upper jaw.
Ask the patient to push up on the edges of the lower rim with both thumbs while opening at the same time to dislodge the appliance from the mouth.
Instruct the patient not to remove the appliance by simply opening the mouth since the wire work may be permanently distorted and the appliance ruined.
Cleaning The Appliance
A stiff toothbrush and any toothpaste can be used to clean the appliance.
The inside of the tooth portion of the appliance should be thoroughly brushed as well as the smooth outside surface.
The same brush can be used to clean the expansion screw.
As Klearway™ is made of thermoacrylic material, do not soak it in water or mouthwash when not in use.
If necessary, advise the patient to use a denture cleanser tablet like Oral Safe™ to help remove stains and to keep the appliance fresh.
(c) One Week Follow Up Appointment
Record the amount of opening of the expansion screw with a Boley gauge.
Check for jaw muscle discomfort and any sore teeth.
If the patient experiences significant jaw discomfort, turn the screw in the reverse direction of the arrow to decrease the amount of mandibular protrusion until the patient is comfortable.
Klearway™ has been designed in the laboratory for this setback from the initial two-thirds forward position if required after the initial insertion.
Relieve the acrylic around any sore or uncomfortable teeth.
A sense of the teeth not touching completely may be experienced by some patients in the morning (this usually disappears within an hour or so). In addition, they may experience an excessive amount of saliva for the first month or so.
(d) One Month Follow Up Appointment
Record the amount of opening of the expansion screw with a Boley gauge.
If the patient wears the appliance every night and is comfortable, instruct the patient to activate the appliance by turning the screw on the top of the appliance two times per week until the next appointment. Each turn or activation in the direction of the arrow will move the lower jaw gradually forward in 0.25 mm increments which has a direct effect on the three-dimensional size of the airway. Klearway™ has been shown to be particularly effective in increasing the size of the velopharynx.
Appliance Activation Methodology
Have the patient insert the tip of the supplied key into the hole on the side of the metal expansion screw at the base of the arrow imprinted on that expansion screw.
Turn or push the key towards the direction of the arrow. This arrow shows the correct movement to advance the lower jaw.
Once the key is completely turned from one side to the other, remove it and a new hole will appear for the next turn. NOTE: If the key is removed before a new hole appears after the completed turn, the patient may be unable to fully place the key into the new hole.
Always remove the key after turning.
Turning the key opposite to the direction of the arrow will close the expansion screw and retract the mandible.
If the screw appears to self-close over time, patients may be shown with a millimetre ruler
how to verify that the screw is indeed opening.
If significant jaw or joint discomfort occurs, advise the patient to stop turning the screw until their next visit.
If the discomfort has not subsided in one or two days, have the patient call the office immediately. Verify the appliance has not been distorted or opened vertically. The anterior shelves should be in contact to prevent any downward mandibular rotation during sleep.
Technique Tip - Ensuring Contact of Anterior Shelves
Any plier may be used to vertically close the arms of the expansion screw to ensure contact of the anterior sliding shelves.
Soften the Klearway™ appliance in hot water.
While holding the expansion screw of the softened and downward oriented Klearway™ from behind the plier, push down on the acrylic portion of the maxillary arch to close the vertical dimension.
Alternatively, slip the mandibular arch off the sliding ends of the forward screw arms by compressing the lower arch to one side to disengage the opposite side. With the two sections apart, bend the vertical section of the anterior two screw wires forward to close the bite. Replace the lower arch by engaging one side and compressing towards that side until the opposite arm can be engaged. Check that the anterior shelves are now in full contact.
(e) Titration Appointment
Some patients stop snoring and feel more rested shortly after Klearway™ is inserted. No further advancement of the mandible is required.
Others may require two or three months of slow and gradual repositioning before a significant treatment effect is noted.
A history from the bed partner to ascertain if the snoring intensity and/or frequency has changed is extremely useful.
When the patient and/or bed partner reports a cessation of snoring and a resolution of symptoms, further advancement of the mandible may not be required.
The expansion screw should be tied off with stainless steel ligature wire or filled in with cold cure acrylic to prevent any further movement of the mandible.
The patient should be referred back to their physician and/or sleep specialist for assessment at this time.
(f) Six Month Follow Up Appointments
If the oral appliance has been shown to be effective and the patient is comfortable, recall appointments should be scheduled at six month intervals.
At each appointment, check the status of the occlusion and verify that the appliance has not been distorted.
Minor cracks in the appliance can be repaired at chairside with cold cure acrylic.
Expansion screws may self close over time and therefore should always be permanently stabilized for long-term Klearway™ wear. During the active expansion phase, patients may be shown with a millimetre ruler how to verify that the screw is opening with each month of turning.
In selected cases, the screw mechanism may be removed completely and the upper and lower arches fused with cold cure acrylic (leaving anterior air holes).
The overall management of the patient’s particular sleep disorder remains the responsibility of the attending physician.