Crystallization and hardening of poly(ethylene-co-vinyl acetate) mouthguards during routine use

Ryoko Kuwahara; Ryotaro Tomita; Natsumi Ogawa; Kazunori Nakajima; Tomotaka Takeda; Hiroki Uehara; Takeshi Yamanobe

doi:10.1038/srep44672

journal article Open Access Mar 15, 2017

Crystallization and hardening of poly(ethylene-co-vinyl acetate) mouthguards during routine use

Ryoko Kuwahara

Ryotaro Tomita Natsumi Ogawa Kazunori Nakajima

Tomotaka Takeda Hiroki Uehara Takeshi Yamanobe

Scientific Reports Vol. 7 No. 1 · Springer Science and Business Media LLC

View at Publisher Save 10.1038/srep44672

Abstract

AbstractMouthguards (MGs) made from poly(ethylene-co-vinyl acetate) (EVA) are widely used in contact sports to prevent injuries such as breaking teeth and lip lacerations and to reduce brain concussion. However, the changes in morphology and the molecular mobility of EVA, which can affect its physical properties during practical usage, have not been precisely examined. Therefore, we attempted to determine the main factors which lead to changes in MG performance after one season of practical use by high school rugby players. Solid-state nuclear magnetic resonance (NMR) and pulse NMR measurements showed the hardening of MGs, which was associated with an increased crystallinity of the EVA resulting from prolonged usage. Furthermore, our data indicated that the increase in the relative amount of the crystalline phase may be primarily attributed to temperature fluctuations and repeated changes in pressure, which could cause the hardening of EVA and eventually diminish the protective ability of MGs.

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Details

Published: Mar 15, 2017
Vol/Issue: 7(1)
License: View

Authors

R

Ryoko Kuwahara

Department of Dental Hygiene, Faculty of Healthcare Sciences Chiba Prefectural University of Health Sciences Chiba Japan

Department of Anatomy, Keio University School of Medicine, Tokyo 160-8582, Japan

T

Tomotaka Takeda

Department of Oral Health and Clinical Science, Division of Sports Dentistry Tokyo Dental College Tokyo Japan

Cite This Article

Ryoko Kuwahara, Ryotaro Tomita, Natsumi Ogawa, et al. (2017). Crystallization and hardening of poly(ethylene-co-vinyl acetate) mouthguards during routine use. Scientific Reports, 7(1). https://doi.org/10.1038/srep44672

Crystallization and hardening of poly(ethylene-co-vinyl acetate) mouthguards during routine use

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