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Purpose: Wearing a sports mouthguard is not only recommended in collision sports, such as American football, boxing, and rugby football, but also in lowcontact sports, such as basketball, handball, and soccer. It is recommended to remove oral prosthetic devices while playing sports to avoid the risk of fracturing the device. However, players with maxillectomy must wear obturator-type prosthetic devices for speech, breathing, and deglutition even while playing sports. Therefore, there is a need for an oral appliance to prevent dental injury while playing sports without the risk of fracturing the device for players who have undergone maxillectomy. In this case, we fabricated and proposed overlay-type and obturator-type customized sports mouthguards for a patient who had undergone maxillectomy and assessments of satisfaction, speech intelligibility, nasopharyngeal closure function, and swallowing function while playing soccer. Results: The patient was only satisfied with the obturator-type mouthguard, and the results of the speech intelligibility, nasopharyngeal closure function, and swallowing tests using the obturator-type mouthguard showed no differences compared to those associated with the previously used prosthetic device. Conclusions: This case may help highlight the importance of providing obturator-type mouthguards for players who have undergone maxillectomy to prevent dental injury and physical and mental discomfort. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to determine the optimal heating conditions for sheet forming using a circle tray by comparing the thickness and fit of mouthguards formed under different conditions. Methods: Mouthguards were fabricated using ethylene vinyl acetate sheets (4.0mm thick) and a vacuum forming machine. The working model was trimmed to a height of 20mm at the incisor and 15mm at the first molar. Two forming conditions were compared: square sheets were pinched by the clamping frame attached to the forming machine; and round sheets were pinched at the top and bottom and stabilized by a circle tray. Each condition was defined when the sheet sagged by 10-mm or 15-mm below the level of the clamp. The thickness of the sheet was determined for the incisal and molar portion. Additionally, the difference in fit according to the forming conditions was measured by examining the cross section. Differences in the thickness or the fit due to forming conditions were analyzed using two-way analysis of variance (ANOVA) followed by Bonferroni's multiple comparison tests. Results: The thickness after formation was thicker at the 10-mm condition than that of 15-mm, and the fit at the 15-mm condition was better when that of 10-mm with square and round sheets. Conclusion: Within the limitation of this study, it was suggested that when forming a mouthguard using a 4.0-mm EVA sheet and a circle tray on a vacuum forming machine, the sheet should be formed at a sagging distance of 10-mm. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: The aim of this study was to evaluate the change in thickness of the mouthguard sheet due to different heating conditions during fabrication. Methods: Mouthguards were fabricated with ethylene vinyl acetate (EVA) sheets (4.0-mm thick) using a vacuum-forming machine, and six conditions which varied the height of the frame above the surface, reversing the sheet while heating, and controlled power on–off of the heater when a specified level of sagging had been attained were used to determine optimal conditions. The working model was trimmed to a height of 20-mm at the incisor and 15-mm at the first molar. Post-molding thickness was determined for the incisal portion (incisal edge and labial surface) and molar portion (cusp, central groove, and buccal surface). Differences in the change in thickness due to heating condition were analyzed using Scheffé’s multiple comparison tests. Results: The heating condition which the sheet frame was lowered to and heated at 50mm below the top of the post, the heater was turned off when the sheet sagged by 10mm, and the sheet was molded when the sagging reached 15mm showed the thickest, what the decrease in the thickness reduction was approximately 0.40–0.44mm at the incisal, and that was 0.35–0.40mm at the molar portions. Conclusion: When molding a mouthguard using an EVA sheet, the thickness of the incisal and molar portions of the mouthguard can be maintained by adjusting the height of the sheet frame and heating conditions, which may be clinically useful. [Copyright &y& Elsevier]

Abstract: Purpose: To investigate the form of mouthguard sheets that best retains its thickness. Methods: Mouthguards were molded using ethylene-vinyl-acetate (EVA) sheets and a suction-type molding device. Five sheet conditions were compared. These were I-N (Incisal part of the cast positioned at the center – Normal sheet), I-H (Incisal part positioned at the center – Horizontal v-shaped groove 30mm from the anterior end), I-C (Incisal part positioned at the center – Convexing v-shaped groove toward the back 10–40mm from the anterior end), C-N (Center part positioned at the center – Normal sheet), and C-C (Center part positioned at the center – Convexing v-shaped groove toward the back 10–30mm from the anterior end). Post-molding thickness was determined for the incisal (incisal edge and labial surface) and molar portion (cusp, central groove, and buccal surface). Sheets were heated until they sagged 15-mm below the clamp. Scheffé multivariate comparison was performed to compare changes in post-molding thickness among sheet conditions. Results: Post-molding thickness of mouthguard material differed significantly between the two portions; rates of thickness reduction were smaller for I-C and C-C compared with other conditions. There were no significant differences between I-C and C-C at any measurement points. Conclusion: The present results suggested that thickness reduction of the EVA sheet material after vacuum-forming may be decreased at both incisal and molar portions if the v-shaped groove with a v-shaped cross section was given in the frontal teeth region of the sheet at the apparatus and materials for this study used. [Copyright &y& Elsevier]

Abstract: Purpose: The aim of this study was to evaluate the change in thickness of different types of step-type mouthguard sheets after suction molding in response to heating conditions for more effective use. Methods: Four types of mouthguard sheets (Impact Guard®) were compared: a step-type sheet; a step-type sheet with a v-shaped groove 30mm from the anterior end; a step-type sheet with a v-shaped groove at the inferior margin of the step portion; and a step-type sheet with a v-shaped groove at the center of the step portion. The working model was trimmed to a height of 20-mm at the incisor and 15-mm at the first molar. The thickness of sheet was measured at points defined on the incisor and molar portion. The heating condition was defined when the sheet sagged by 15-mm below the level of the clamp. Differences in the percent change in thickness from types of sheets were analyzed using Scheffé’s multiple comparison test. Additionally, the sheet type of thickness change with smallest was compared between the 15-mm and 20-mm sheet-sagging condition by paired t-test. Results: The sheet with a v-shaped groove at the center of the step portion showed smallest reduction in thickness. With this type of sheet, no significant difference in thickness was observed under heating conditions. Conclusions: The present results demonstrate the thickness of the incisor and molar portions of a step-type mouthguard sheet can be maintained by creating a v-shaped groove at the center of the step portion, regardless of heating condition. [Copyright &y& Elsevier]

Abstract: Purpose: The aim of this study was to determine the color difference of mouthguard in hardness, water sorption and thickness after forming EVA sheets. Six different colors of sheets were tested for each of three manufacturers. Methods: The materials used in this study were mouthguard sheets made by three manufacturers. Each manufacturer supplied six colors: clear, white, yellow, blue, red, and black. Shore A hardness and water sorption were measured based on ISO 7619 and 1817, respectively. The thickness after formation was measured by using a measuring device. The differences in hardness, water sorption and thickness after formation were analyzed by two-way analysis of variance. The correlation between the hardness and changes in thickness was analyzed using Pearson''s product-moment correlation coefficient. Results: Shore A hardness was different depending upon various colored sheets and manufactures. There were differences in the water sorption depending upon some colored sheet among manufacturers. There was a significant difference in the thickness after formation was found to be dependent upon few colors of the sheets on one manufacturer''s product on the anterior teeth and on three products on posterior teeth. A negative correlation between the hardness and the change of thickness was found in two products. Conclusions: The present study suggests that the Shore A hardness and thickness after formation varied depending upon the colors of the EVA sheets and manufactures. A correlation between the hardness and change of thickness was observed in two manufactures that suggests that the hard sheets tend to reduce in thickness greater than that in softer ones. [Copyright &y& Elsevier]

Abstract: Purpose: We have developed a new type of laminated mouthguard, the Hard & Space mouthguard, which incorporates a hard material insert and a space to prevent contact between the mouthguard and the buccal surfaces of the teeth. The purpose of this study was to investigate the effect of this new design on shock absorption. Methods: Three types of mouthguard (a conventional laminated EVA mouthguard and two 3-layer type “Hard & Space” mouthguards made of 1.8-mm or 3.0-mm thick pre-laminated material (Konbiplast) and EVA with a 1.0-mm space) were impacted. Shock absorption was measured by means of a pendulum type steel ball impact testing machine at impact distances of 10, 20, and 30cm and a dental study model with strain gauges attached to the lingual surfaces and an accelerometer fixed to the maxilla. Results: Distortion of the impacted tooth and acceleration of the model were significantly reduced by all types of mouthguard at all 3 impact distances. The effect of the mouthguard was remarkable in terms of tooth distortion: both thicknesses of Hard & Space mouthguard showed more than 90% shock absorption, compared with only approximately 55–78% with an EVA mouthguard. Furthermore, shock absorption with the thicker 3.0-mm Hard & Space mouthguard reached more than 95% at the highest impact power. Conclusion: Within the limitations of this laboratory study, Hard & Space mouthguards showed significantly greater buffer capacity than a conventional EVA mouthguard in terms of tooth distortion at the 3 impact powers tested. [Copyright &y& Elsevier]

The article presents a study which examines and measured the effects of mouthguards on tooth distortion caused by clenching. The software used for the analysis of tooth distortion includes the AcquKnowledge from BIOPAC System Inc. and the SPSS from SPSS Japan Inc. The results indicate that mouthguards prevent tooth distortions and periodontal damage caused by clenching in contact sports.

Purpose: Wearing a sports mouthguard is not only recommended in collision sports, such as American football, boxing, and rugby football, but also in low-contact sports, such as basketball, handball, and soccer. It is recommended to remove oral prosthetic devices while playing sports to avoid the risk of fracturing the device. However, players with maxillectomy must wear obturator-type prosthetic devices for speech, breathing, and deglutition even while playing sports. Therefore, there is a need for an oral appliance to prevent dental injury while playing sports without the risk of fracturing the device for players who have undergone maxillectomy.In this case, we fabricated and proposed overlay-type and obturator-type customized sports mouthguards for a patient who had undergone maxillectomy and assessments of satisfaction, speech intelligibility, nasopharyngeal closure function, and swallowing function while playing soccer., Results: The patient was only satisfied with the obturator-type mouthguard, and the results of the speech intelligibility, nasopharyngeal closure function, and swallowing tests using the obturator-type mouthguard showed no differences compared to those associated with the previously used prosthetic device., Conclusions: This case may help highlight the importance of providing obturator-type mouthguards for players who have undergone maxillectomy to prevent dental injury and physical and mental discomfort.