Monday, November 02, 2009

Characterization of mouthguard materials: Thermal properties of commercialized products

Dental Materials
Volume 25, Issue 12, Pages 1593-1602 (December 2009)

Characterization of mouthguard materials: Thermal properties of commercialized products

Trenton E. GouldaCorresponding Author Informationemail address, Scott G. Pilanda, Junghwan Shinb, Olivia McNairb, Charles E. Hoyleb, Sergei Nazarenkob

Received 15 July 2009; accepted 11 August 2009.

Abstract
Objectives

Several mechanisms have been purported to describe how mouthguards protect the orofacial complex against injury. As the properties needed for these mechanisms to be effective are temperature and frequency dependent, the specific aim of this study was to provide a comprehensive thermal characterization of commercial mouthguard materials.
Methods

Five commercially representative thermoplastic mouthguard materials (Essix™ Resin, Erkoflex™, Proform™-regular, Proform™-laminate, and Polyshok™) were tested. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) techniques were implemented to measure thermal transitions and mechanical properties. Measurements were conducted three times per sample. One-way ANOVA and one-sample t-tests were used to test for differences between commercial products on selected mean thermal property values.
Results

The DSC measurements indicated no differences between commercial materials for mean glass transition (p=0.053), onset melt (p=0.973), or peak melt (p=0.436) temperatures. Likewise, DMA measurements revealed no differences between commercial materials for the mean glass transition (p=0.093), storage modulus (p=0.257), or loss modulus (p=0.172) properties, respectively. The one-sample t-tests revealed that glass transition temperatures were different from intra-oral temperature (p<0.005) for all materials.
Significance

Commercialized mouthguard materials are sensitive to repetitive heating and cooling cycles, prolonged thermal treatment, and have glass transitions well below their end-use intra-oral temperature. As such, these materials are functioning as elastomers and not optimal mechanical damping materials. Dental clinicians, healthcare practitioners, or end-users should be aware that these materials are at best problematic with respect to this protective mechanism.

1 comment:

Mouth Guard said...

Types of mouth guards:

In general you will find that there are three basic types of mouth guards that are available: stock mouthpieces, "boil and bite" mouth guards, and custom guards.
stock mouth guard
The term "stock mouth guard" refers to preformed mouthpieces that are sold ready to be used without any additional customization by the wearer. This type of mouth guard is usually the cheapest type of guard, but in this instance it seems to be an example of you get what you pay for. The level of protection provided by stock guards is usually minimal.

In most cases you will find that stock mouth guards are only manufactured in just a few sizes (typically small, medium, and large). As a result for many athletes these guards will be uncomfortable to wear and will not stay in place well. Also related to these same size limitations, stock mouthguards often will not cover over all of the back teeth as is needed for adequate protection.

To compensate for the poor retention of a stock mouth guard an athlete will often clench their teeth together, so to hold the guard in place. This clenching activity can make it difficult for the player to speak and breathe, which in turn may provide a reason for them not to wear it. In some cases an athlete may attempt to improve the functionality or comfort of their stock mouthguard by way of trimming it, but this type of customization can serve to compromise the level of protection that the guard can provide.

"Boil and bite" mouth guards.
A "boil and bite" mouth guard refers to a type of guard that is made out of thermoplastic materials. The idea is that the athlete customizes the fit of the mouthguard by immersing it in hot water (until it becomes soft and pliable) and then placing it in their mouth and subsequently using their fingers, lips, tongue, cheeks, and biting pressure to seat and form the contours of the guard.

Boil and bite mouth pieces are the most used type of mouth guard. If choosing this type of mouthpiece a size must be chosen that covers all of the wearer's front and back teeth. A criticism of this type of protector is that during the customization process the thickness of the plastic covering the chewing surface of the teeth can become thin, thus minimizing the amount of protection that the guard is capable of providing. Another common criticism aimed at boil and bite mouth guards is that they can be bulky. The retention of this type of mouth guard can be expected to be better than a stock guard buy not as good as the fit of a custom mouth guard.

Custom mouth guards.
Custom mouth guards are sports mouth protectors that are individually made for an athlete. A well-designed custom mouthguard is typically considered to be able to provide the greatest level of protection for an athlete as compared to either a stock or boil and bite guard. The design of a custom guard can be individualized not only for the athlete but in some cases also for the specific sport that will be played when it is being worn.

The fit and comfort of a custom mouthguard can be expected to be excellent. The more comfortable and unobtrusive a mouthguard is the greater the likelihood that the athlete will wear it at all times. Additionally, the retention of a custom guard can be expected to be superior and therefore produce less interference with speech and breathing than other types of guards. While the cost of this type of appliance is more than a stock or boil and bite mouthpiece it should be considered money well spent. By MouthGuard