MSA  Vol.10 No.6 , June 2019
Difference in Surface Roughness of Ethylene-Vinyl-Acetate Sheet before and after Application of Finishing Liquid: Part 2 Changes over Time in Surface Roughness
Abstract: Surface texture of the mouthguard affects the sense of adaptation in the athlete and further affects hygiene. The aim of this study was to investigate the changes over time in surface roughness after finish polishing of ethylene vinyl acetate (EVA) sheets and before and after finishing liquid application, and to evaluate its effectiveness. Total of 160 specimens of EVA (3 × 3 mm) were divided into 4 groups according to polishing condition (control = unpolished; RB = Robinson-brush; LF = Lisko-Fine, and MW = Mouthguard-wheel). Polishing was performed at low speed by using a straight headpiece. The rotation speed was 5000, 4000 and 6000 rpm for RB, LF, and MW, respectively. Next, a finishing liquid was applied to each specimen. Changes over time in surface roughness before and after application of the finishing liquid were compared by a non-contact surface shape measuring machine. The arithmetic average height (Sa) was measured. The measurement time points were before application, immediately after application, and at 5, 10, and 15 min after application. The changes over time of the surface roughness of the sheet before and after application of the finishing liquid were analyzed by two-way analysis of variance and Bonferroni’s multiple comparison tests. Surface roughness of the specimen before application became coarse in the order of control; MW, LF and RB, and Sa were about 0.21 μm, 2.03 μm, 2.94 μm, and 4.72 μm, respectively. That showed the same order after finishing liquid application. Significant decrease in Sa for RB and LF were seen at 10 min after application and at 5 min after application, respectively. Sa of MW was not significantly different before and after application. The results of this study showed that a lubricity of about 1.0 μm increases within 5 - 10 min of application of finishing liquid, but in cases where polishing was performed to about 2.0 μm; the application of finishing liquid has no ef-fect.
Cite this paper: Takahashi, M. , Bando, Y. (2019) Difference in Surface Roughness of Ethylene-Vinyl-Acetate Sheet before and after Application of Finishing Liquid: Part 2 Changes over Time in Surface Roughness. Materials Sciences and Applications, 10, 451-460. doi: 10.4236/msa.2019.106033.

[1]   Verissimo, C., Costa, P.V., Santos-Filho, P.C., Tantbirojn, D., Versluis, A. and Soares, C.J. (2016) Custom-Fitted EVA Mouthguards: What Is the Ideal Thickness? A Dynamic Finite Element Impact Study. Dental Traumatology, 32, 95-102.

[2]   Gialain, I.O., Coto, N.P., Driemeier, L., Noritomi, P.Y. and Dias, R.B. (2016) A Three-Dimensional Finite Element Analysis of the Sports Mouthguard. Dental Traumatology, 32, 409-415.

[3]   Bochnig, M.S., Oh, M.J., Nagel, T., Ziegler, F. and Jost-Brinkmann, P.G. (2017) Comparison of the Shock Absorption Capacities of Different Mouthguards. Dental Traumatology, 33, 205-213.

[4]   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.

[5]   Tribst, J.P.M., de Oliveira, Dal Piva, A.M., Borges, A.L.S. and Bottino, M.A. (2018) Influence of Custom-Made and Stock Mouthguard Thickness on Biomechanical Response to a Simulated Impact. Dental Traumatology, 34, 429-437.

[6]   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.

[7]   Kawai, K., Urano, M. and Ebisu, S. (2000) Effect of Surface Roughness of Porcelain on Adhesion of Bacteria and Their Synthesizing Glucans. Journal of Prosthetic Dentistry, 86, 664-667.

[8]   Leal, A., Paula, A., Ramalho, A., Esteves, M., Ferreira, M.M. and Carrilho, E. (2015) Roughness and Microhardness of Composites after Different Bleaching Techniques. Journal of Applied Biomaterials & Functional Materials, 13, e381-e388.

[9]   Needleman, I., Ashley, P., Petrie, A., Fortune, F., Turner, W., Jones, J., Niggli, J., Engebretsen, L., Budgett, R., Donos, N., Clough, T. and Porter, S. (2013) Oral Health and Impact on Performance of Athletes Participating in the London 2012 Olympic Games: A Cross-Sectional Study. Journal of Sports Medicine, 47, 1054-1058.

[10]   Takahashi M, 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.

[11]   Takahashi, M. and Bando, Y. (2018) Thermoforming Method to Effectively Maintain Mouthguard Thickness: Effect of Moving the Model Position Just before Vacuum Formation. Dental Traumatology, 35, 121-127.

[12]   Almeida, M.H., Ceschim, G.V., Ioriom, N.L.P.P., Póvoa, H.C.C., Cajazeira, M.R.R., Guimaraes, G.S, Antunes, L.S. and Antunes, L.A.A. (2018) Influence of Thickness, Color, and Polishing Process of Ethylene-Vinyl-Acetate Sheets on Surface Roughness and Microorganism Adhesion. Dental Traumatology, 34, 51-57.

[13]   Sul, Y.T., Kang, B.S., Johansson, C., Um, H.S., Park, C.J. and Albrektsson, T. (2009) The Roles of Surface Chemistry and Topography in the Strength and Rate of Osseointegration of Titanium Implants in Bone. Journal of Biomedical Materials Research Part A, 89, 942-950.

[14]   Koshihara, T., Hara, M., Sato, T., Hayashibara, T., Masuda, T. and Shinya, A. (2016) Evaluation of the Surface Texture of CAD/CAM-Produced Crowns among Various Types of CAD/CAM Milling Systems. The Shikwa Gakuho, 116, 149-153.

[15]   Takahashi, M. and Bando Y. (2018) Difference in Surface Roughness of Ethylene-Vinyl-Acetate Sheet before and after Application of Finishing Liquid. Materials Sciences and Applications, 9, 985-992.

[16]   Olympus Scientific Solutions Americas Corp. Height Parameters (Amplitude Mean in the Height Direction).