Weekend courses teaching oral appliance therapy are conducted all over the country and with over 100 commercially available oral appliances it can be really difficult to navigate the appliance selection process. Considering the mechanical functioning of the appliance is essential when determining which one to choose for treatment, but often times the material used to construct the appliance is equally as important and overlooked. Two of the most generally known materials are heat-cured hard acrylic and dual laminates. Studies have shown that while there are advantages and disadvantages to each material, most doctors favor heat-cured hard acrylic appliances because they have a compelling superiority over the latter when it comes to fitting, repairs, longevity and patient comfort.
Some of the most pressing issues in doctors’ offices are fitting the appliance correctly in the patient’s mouth. Obstructive sleep apnea is a serious medical condition that can sometimes be so severe that doctors don’t have time to send back an appliance to be remade if it doesn’t fit. National statistics show a lower percentage of remakes in hard acrylic formed appliances. The reason for this can partly be credited to ease of modification chairside due to minor cosmetic dental changes. If anything changes in the patient’s mouth for example, the addition of a crown, a completely new appliance must be created as realignment can’t be done in laminate appliances. On a hard acrylic appliance, the appliance can sometimes be ground to re-fit. Furthermore, the addition of clasps in hard acrylic appliances provide further retention whereas a laminate appliance does not allow for it to contain clasps.
Repairs are inevitable when it comes to oral appliances. Fortunately when repairs are necessary, the ramifications can be minimized simply by the choice of appliance design. Doctors can take a more basic approach to repairing hard acrylic appliances including, but not limited to, effortlessly bonding new acrylic to cracks or chips in their own. Mending a laminate appliance can become more complicated when considering the soft liner located on the inside. Many times that same soft layer has been shown to absorb moisture and start to yellow with bacteria. Unfortunately this is not a matter of repair, rather a matter of replacement.
Gergen’s Orthodontic Lab, which is the largest manufacturer of the Sleep Herbst in the country, has seen hard acrylic appliances last over to 20 years. Regrettably, the soft layer in laminate appliances always eventually loses the bond to the hard layer- meaning it will always peel apart over time, leading to the doctor sending it back to the manufacturing lab to be rebuilt.
Typically patient comfort is one of the cornerstones of the decision making process in choosing treatments. While each of the designs have equal amounts of pros and cons to patient satisfaction, time and time again there have been proven patterns and methods that demonstrate it is easier to overcome the cons associated with treatment via hard acrylic appliances. This is contrary to general belief being that dual laminates are more comfortable. Moreover, tongue space is greatly reduced in dual laminate appliances due to the extra layer being present.
All things considered, both hard acrylic and dual laminate appliances grant favorable benefits in many cases. Clearly though when taking into account the comparison of both designs regarding fitting, repairs, longevity and patient comfort the preferred choice when selecting one of the two is the hard acrylic design more often than not.
