MSA  Vol.11 No.3 , March 2020
Thermoforming Technique for Suppressing Reduction in Mouthguard Thickness
Abstract: Wearing a mouthguard reduces the risk of sports-related injuries, but the material and thickness of the mouthguard has a substantial impact on its effectiveness and safety. The aim of this study was to establish a thermoforming technique in which the model position is moved just before formation to suppress the reduction in thickness. Mouthguards were vacuum formed using ethylene-vinyl-acetate sheets with a thickness of 2.0, 3.0, and 4.0 mm. The working model was trimmed to the height of 25-mm at the maxillary central incisor and 20-mm at first molar. The model was placed with its anterior rim positioned 40-mm from the front of the forming table. Two forming methods were compared: 1) the sheet was formed when it sagged 15-mm at the top of the post under normal conditions (control); and 2) the sheet frame at the top of the post was lowered and the model was covered when the sheet sagged 15-mm, the rear side of the model was pushed forward 20-mm, and the mouthguard was formed (MP; model position). Sheet thickness after fabrication was determined for the incisal edge, labial surface, and buccal surface using a specialized caliper accurate to 0.1-mm. The difference in the reduction in thickness depending on the forming methods and sheet thicknesses were analyzed by two-way ANOVA and Bonferroni’s multiple comparison tests. Reduction in thickness was greater for thicker sheets, and the reduction in thickness for the MP was less than that for the control. The reduction in labial for the MP was an exception; the reduction in thickness was only about half that of the control. The thermoforming technique of moving the model forward just before vacuum formation was effective for suppressing the mouthguard thickness reduction, which in thickness of the labial side can be reduced to about half of the normal forming method.
Cite this paper: Takahashi, M. , Bando, Y. (2020) Thermoforming Technique for Suppressing Reduction in Mouthguard Thickness. Materials Sciences and Applications, 11, 184-194. doi: 10.4236/msa.2020.113012.

[1]   Going, R.E., Loehman, R.E. and Chan, M.S. (1974) Mouthguard Materials: Their Physical and Mechanical Properties. The Journal of the American Dental Association, 89, 132-138.

[2]   Bishop, B.M., Davies, E.H. and von Fraunhofer, J.A. (1985) Materials for Mouth Protectors. Journal of Prosthetic Dentistry, 53, 256-261.

[3]   McNutt, T., Shannon, S.W., Wright, J.T. and Feinstein, R.A. (1989) Oral Trauma in Adolescent Athletes: A Study of Mouth Protectors. Pediatric Dentistry, 11, 209-213.

[4]   Johnsen, D.C. and Winters, J.E. (1991) Prevention of Intraoral Trauma in Sports. Dental Clinics of North America, 35, 657-666.

[5]   Park, J., Shaull, K., Overton, B. and Donly, K. (1994) Improving Mouthguards. Journal of Prosthetic Dentistry, 72, 373-380.

[6]   Westerman, B., Stringfellow, P.M. and Eccleston, J.A. (1995) Forces Transmitted through EVA Mouthguard Materials of Different Types and Thickness. Australian Dental Journal, 40, 389-391.

[7]   Padilla, R., Dorney, B. and Balikov, S. (1996) Prevention of Oral Injuries. Journal of the Canadian Dental Association, 31, 30-36.

[8]   Bemelmanns, P. and Pfeiffer, P. (2001) Shock Absorption Capacities of Mouthguards in Different Types and Thicknesses. International Journal of Sports Medicine, 22, 149-153.

[9]   Takahashi, M., Koide, K. and Mizuhashi, F. (2013) Variation in Mouthguard Thickness Due to Different Heating Conditions during Fabrication. Journal of Prosthodontic Research, 57, 179-185.

[10]   Takahashi, M., Koide, K. and Mizuhashi, F. (2015) Variation in Mouthguard Thickness Due to Different Heating Conditions during Fabrication: Part 2. Dental Traumatology, 31, 18-23.

[11]   Takahashi, M., Koide, K., Mizuhashi, F. and Sato, T. (2015) Investigation of Vacuum Forming Techniques for Reduction of Loss in Mouthguard Thickness: Part 2 Effects of Sheet Grooving and Thermal Shrinkage. Dental Traumatology, 31, 314-317.

[12]   Farrington, T., Coward, T., Onambele-Pearson, G., Taylor, R.L., Earl, P. and Winwood, K. (2016) The Effect of Model Inclination during Fabrication on Mouthguard Calliper-Measured and CT Scan-Assessed Thickness. Dental Traumatology, 32, 192-200.

[13]   Takahashi, M., Koide, K., Satoh, Y. and Iwasaki, S. (2016) Heating Methods for Reducing Unevenness Softening of Mouthguard Sheets in Vacuum-Pressure Formation. Dental Traumatology, 32, 316-320.

[14]   Mizuhashi, F., Koide, K. and Mizuhashi, R. (2017) Influence of Working Model Angle on the Formation of a Pressure-Formed Mouthguard. Dental Traumatology, 33, 189-193.

[15]   Takahashi, M. and Bando, Y. (2019) Thermoforming Method to Effectively Maintain Mouthguard Thickness: Effect of Moving the Model Position Just before Vacuum Formation. Dental Traumatology, 35, 121-127.

[16]   Mizuhashi, F. and Koide, K. (2019) Vacuum-Formed Mouthguard Fabrication to Obtain Proper Fit Using Notched Sheet. Dental Traumatology, 35, 204-211.

[17]   Takahashi, M. and Bando, Y. (2019) Thermoforming Technique for Maintaining the Thickness of Single-Layer Mouthguard during Pressure Formation. Dental Traumatology, 35, 285-290.

[18]   Takahashi, M. and Bando, Y. (2019) Movement of Model Position Just before Vacuum Forming to Ensure Mouthguard Thickness: Part 2 Effect of Model Moving Distance. Dental Traumatology, 35, 291-295.

[19]   Takahashi, M., Takahashi, F. and Morita, O. (2008) Thickness of Mouthguard Sheet Material after Vacuum Forming Process Depending on the Thickness of Mouthguard Sheet. Journal of Prosthodontic Research, 52, 465-472.

[20]   Takahashi, M., Koide, K. and Mizuhashi, F. (2012) Influence of Color Difference of Mouthguard Sheet on Thickness after Forming. Journal of Prosthodontic Research, 56, 194-203.

[21]   Takahashi, M., Koide, K. and Iwasaki, S. (2016) Thickness of Mouthguard Sheets after Vacuum-Pressure Formation: Influence of Mouthguard Sheet Material. Dental Traumatology, 32, 201-205.

[22]   Takahashi, M., Satoh, Y. and Iwasaki, S. (2017) Effect of Thermal Shrinkage during Thermoforming on the Thickness of Fabricated Mouthguards: Part 2 Pressure Formation. Dental Traumatology, 32, 106-109.

[23]   Takahashi, M., Koide, K., Satoh, Y. and Iwasaki, S. (2016) Shape Change in Mouthguard Sheets during Thermoforming. Dental Traumatology, 32, 379-384.

[24]   Takahashi, M., Araie, Y., Satoh, Y. and Iwasaki, S. (2017) Shape Change in Mouthguard Sheets during Thermoforming: Part 2 Effect of the Anteroposterior Position of the Model on Fabricated Mouthguard Thickness. Dental Traumatology, 33, 114-120.

[25]   Takahashi, M., Koide, K. and Mizuhashi, F. (2014) Influence of Sheet Material Shape on the Thickness and Fit of Mouthguards. Dental Traumatology, 30, 455-460.

[26]   Takeuchi, M. and Togaya, N. (2006) Effectively of Thermoforming Process for Fabricating of Intraoral Apparatus. Sunashobo, Tokyo, Japan, 21-2+33-44+81. (In Japanese)

[27]   Gawlak, D., Mierzwińska-Nastalska, E., Mańka-Malara, K. and Kamiński, T. (2015) Assessment of Custom and Standard, Self-Adapted Mouthguards in Terms of Comfort and Users Subjective Impressions of Their Protective Function. Dental Traumatology, 31, 113-117.

[28]   Gawlak, D., Mańka-Malara, K., Mierzwińska-Nastalska, E., Gieleta, R., Kamiński, T. and Luniewska, M. (2017) A Comparison of Impact Force Reduction by Polymer Materials Used for Mouthguard Fabrication. Acta of Bioengineering and Biomechanics, 19, 89-95.

[29]   Guérard, S., Barou, J.L., Petit, J. and Poisson, P. (2017) Characterization of mouthguards: Impact performance. Dental Traumatology, 33, 281-287.

[30]   Erkodent Dental Products. ERKODENT© Thermoforming Systems.

[31]   Dreve Dentamid. Thermoforming.

[32]   Waked, E.J. and Caputo, A.A. (2005) Thickness and Stiffness Characteristics of Custom-Made Mouthguard Materials. Quintessence International, 36, 462-466.

[33]   Del, R.G. and Leyte, V.M.A. (2007) Fabricating a Better Mouthguard: Part I Factors Influencing Mouthguard Thinning. Dental Traumatology, 23, 149-154.

[34]   Geary, J.L. and Kinirons, M.J. (2008) Post Thermoforming Dimensional Changes of Ethylene Vinyl Acetate Used in Custom-Made Mouthguards for Trauma Prevention: A Pilot Study. Dental Traumatology, 24, 350-355.

[35]   Maeda, M., Takeda, T., Nakajima, K., Shibusawa, M., Kurokawa, K. and Shimada, A. (2008) In Search of Necessary Mouthguard Thickness: Part 1 from the View Point of Shock Absorption Ability. Journal of the Japan Prosthodontic Society, 52, 211-219.

[36]   Mizuhashi, F., Koide, K., Takahashi, M. and Mizuhashi, R. (2012) A Method to Maintain the Thickness of the Mouthguard after the Vacuum Forming Process: Changes of the Holding Conditions of the Mouthguard Sheet. Dental Traumatology, 28, 291-295.

[37]   Kojima, I., Takeda, T., Nakajima, K., Narimatsu, K., Konno, M., Ozawa, T. and Ishigami, K. (2015) Thinning Factors Influence on Custom-Made Mouthguards Thermoforming. Dental Traumatology, 31, 103-112.

[38]   Guevara, P.H., Hondrum, S.O. and Reichl, R.B. (2001) A Comparison of Commercially Available Mouthguards and a Custom Mouthguard. General Dentistry, 49, 402-406.

[39]   Takahashi, M. and Bando, Y. (2018) Effect of the Anteroposterior Position of the Model on Fabricated Mouthguard Thickness: Part 2 Influence of Sheet Thickness and Material. Dental Traumatology, 34, 370-377.