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Case Reports in clinical Medicine 2019年第6期8卷 147-151页

作者： Yoshiro Fujii Shin-Kobe dental clinic Chuou-Ku Kobe Japan

Two customized mouthguards were developed for a 35-year-old male kickboxer. These were identical in thickness (the vertical dimension between the upper and lower jaws), the material, and similar in form (visible outline);however, one mouthguard was designed such that the horizontal jaw position was determined by the maximal grip strength obtained by the subject during the Bi-Digital O-Ring Test. Both mouthguards were satisfactory in terms of how they felt during wearing and breathing;however, the subject achieved higher kicking force, punching force, and back muscle strength while using the mouthguard with an optimized horizontal jaw position. These findings suggest that to enhance sports performance, it may be important to determine the optimal biting position. The grip strength obtained during the Bi-Digital O-Ring Test is a useful parameter for this assessment.

关键词： Mouthguard Sports Performance Bi-Digital O-Ring Test

Task sharing: situation analysis about capacity and resources for management of diabetic retinopathy in Pakistan

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International Journal of Ophthalmology(English edition) 2019年第5期12卷 809-814页

作者： Mufarriq Shah Ayesha Noor C Alex Harper Jill Elizabeth Keeffe Pakistan Institute of Community Ophthalmology Hayatabad Medical Complex Vision and dental Care clinic Centre for Eye Research Australia Department of OphthalmologyUniversity of Melbourneand Royal Victorian Eye and Ear Hospital LV Prasad Eye Institute

AIM: To assess the capacity and resources of eye care facilities, using the WHO Health Systems Framework, to manage diabetic retinopathy(DR) through task ***: Using purposive sampling, four participants(administrators) from four selected hospitals in two provinces in Pakistan were recruited for this cross-sectional study. A survey, to assess the capacity and resources of the selected eye care facilities for the feasibility to adopt task sharing in management of DR to prevent vision loss, was emailed to participants who were asked to complete. Responses to open-ended questions were entered into a Microsoft Excel spread sheet and inductive approach was applied for ***: All the surveyed eye care facilities offer eye care services for people with diabetes and DR. All surveyed eye care facilities have a shortage in the number of human resources across all cadres. Optometrists and mid-level eye care workers did not have active roles in DR screening and management in all four hospitals. All the hospitals surveyed did not have a computerized record management system for patients who visit ophthalmologists for eye examinations. Equipment for detection and management of DR were short in number and main users were ophthalmologists. There was no policy for population-based screening program for detection of DR in any of the surveyed ***: A system-based approach to manage DR is needed. The capacity of eye care facilities and the potential to improve access of people with diabetes to eyecare services can be enhanced through implementation of task sharing.

关键词： task sharing capacity diabetes diabetic retinopathy Pakistan

Dependence of Thermoformed Mouthguard Thickness on Model Height in Single-Layer and Laminated Mouthguards

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Materials Sciences and Applications 2022年第8期13卷 469-478页

作者： Mutsumi Takahashi Yogetsu Bando Department of Physiology The Nippon Dental University School of Life Dentistry at Niigata Niigata Japan BANDO dental clinic Ishikawa Japan

The height of the working model affects the mouthguard thickness. The aim of this study was to clarify the difference in the effect of model height on the thickness between single- and double-layered mouthguards. Mouthguards were thermoformed using ethylene-vinyl-acetate sheets and a pressure molding machine. Working models were three hard gypsum models with the height of the anterior part trimmed to 25 mm (model A), 30 mm (model B), and 35 mm (model C). Three molding conditions were compared: a single-layered mouthguard using a 4.0-mm thick-sheet (S4);a double-layered mouthguard using a 3.0-mm-thick sheet on the first-layer and a 2.0-mm-thick sheet on the second-layer (L32);and a double-layered mouthguard using 3.0-mm-thick sheets on first- and second-layers (L33). Analysis was performed by two-way ANOVA and a simple main effect test for the differences in the mouthguard thickness depending on the model height and the molding condition. Under all molding conditions, the labial and buccal thicknesses tended to become thinner as the model height increased, and models B and C were thinner by about 6% - 7% and about 14% - 16% than model A, respectively. The cusp thickness was not affected by the model height in L32 and L33, but in S4, models B and C were thinner about 14% or more than model A. Significant differences were observed among molding conditions, and S4 P < 0.01). This study suggested that the degree of the decrease in mouthguard thickness due to the increase the model height was similar for the single- and double-layered mouthguards on the labial and buccal sides, and increasing the model height by 5 mm and 10 mm decreased the thickness by about 6% - 7% and about 14% - 16%, respectively. At the cusp, only the single-layered mouthguard was affected by the model height.

关键词： Mouthguard Thermoforming Thickness Working Model

Mouthguard Thermoforming Method to Decrease Palatal Thickness While Maintaining Labial and Buccal Thickness

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Materials Sciences and Applications 2020年第6期11卷 370-381页

作者： Mutsumi Takahashi Yogetsu Bando Department of Physiology The Nippon Dental University School of Life Dentistry at Niigata Niigata Japan BANDO dental clinic Ishikawa Japan

Wearing a mouthguard reduces the risk of sports-related injuries, but a more comfortable design is required in order to increase the wearing rate. The aim of this study was to investigate a thermoforming method that decreases palatal thickness while maintaining labial and buccal thickness. Mouthguards were fabricated from an ethylene-vinyl acetate sheet (thickness: 4.0 mm) by using a vacuum forming machine. Four working models were prepared: 1) the anterior height was 25-mm and the posterior height was 20-mm (model A), 2) model A with the palate trimmed (model B), 3) heights 5 mm greater than model A (model C), and 4) model C with the palate trimmed (model D). The two forming conditions were as follows: 1) The sheet was formed when it sagged 15 mm below the level of the sheet frame at the top of the post under ordinary use (control);2) The sheet frame at the top of the post was lowered and the sheet covered the model when it sagged by 15 mm. The rear side of the model was pushed to move the model forward 20 mm, and then the sheet was formed (MP). Differences in mouthguard thickness due to forming conditions and model forms were analyzed by two-way analysis of variance and Bonferroni’s multiple comparison tests. Difference in forming conditions was similar for all model forms;for the MP, the thickness of the incisal edge, labial surface, cusp and buccal surface were greater, and the palatal surface was thinner than the control. On the labial and buccal surface, the thickness difference due to the model form was observed only for the MP, and models A and B were thicker than models C and D. The palatal thickness tended to be thin in the models with the trimmed palate. This study suggested that the labial and buccal thickness of the mouthguard can be maintained, and the palatal thickness can be decreased by using the model with the palate trimmed with the forming method in which the model position is moved forward immediately before the vacuum formation.

关键词： Mouthguard Thermoforming Thickness Model Trimming Moving Model Position

Factors Affecting Thermal Shrinkage of Mouthguard Sheet during Thermoforming: Model Shape and Sheet Material Thickness

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Materials Sciences and Applications 2022年第4期13卷 133-143页

作者： Mutsumi Takahashi Yogetsu Bando Department of Physiology The Nippon Dental University School of Life Dentistry at Niigata Niigata Japan BANDO dental clinic Ishikawa Japan

The effectiveness and safety of the mouthguard depend on the sheet material thickness. The thickness of the thermoformed mouthguard is affected by the model undercut and the thermal shrinkage that occurs when the extruded-molded sheet is reheated. The aim of this study was to clarify the influence of the undercut amount of the model and the thickness of the sheet material on the thermal shrinkage of the extruded sheet. The mouthguard sheet used ethylene-vinyl acetate resin with a thickness of 4.0 mm (4M) and 3.0 mm (3M) and was manufactured by extrusion molding. The working models were three hard gypsum models with the undercut amount on the labial side trimmed to 0? (U0), 10? (U10), and 20? (U20). Mouthguard thickness after vacuum formation was compared between the conditions formed so that the extrusion direction was vertical (condition V) or parallel (condition P) to the model midline. Differences in the reduction rate of the mouthguard thicknesses of the labial and buccal side depending on the sheet extrusion direction, model angle, and sheet material thickness were analyzed by three-way ANOVA and Bonferroni method. The reduction rate of the thickness in condition P was significantly greater than in condition V under all conditions except U0-4M on the labial side and U0-4M and U10-4M on the buccal side. In all models, the reduction rate of the thicknesses was significantly greater in 3M than in 4M in the same extrusion direction. In both 4M and 3M, the reduction rate of the thicknesses tended to increase as the amount of undercut increased in each extrusion direction. This study suggested that a model with a large amount of undercut on the labial side or a thin sheet had a significant effect on the thermal shrinkage of the mouthguard sheet during thermoforming, which leads to the thinning of the mouthguard.

关键词： Mouthguard Thermoforming Thermal Shrinkage Model Shape Thickness

Effect of Molding Technique That Move Model Position Just before Formation in Production of Laminated Mouthguard

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Materials Sciences and Applications 2023年第6期14卷 325-335页

作者： Mutsumi Takahashi Yogetsu Bando Department of Physiology The Nippon Dental University School of Life Dentistry at Niigata Niigata Japan BANDO dental clinic Ishikawa Japan

Many molding techniques have been researched to ensure the thickness of custom mouthguards. The aim of this study was to clarify the effect on the thickness of a laminated mouthguard of a molding technique in which the model position is moved forward just before molding. Mouthguards were molded using a 3.0-mm-thick ethylene vinyl acetate mouthguard sheet and a pressure molding machine. The molding method was the normal molding method (condition C) and the molding technique (condition MP) in which the model position was moved 20 mm forward just before molding. Regarding the molding of the first layer (F) and the second layer (S), the following four molding methods based on the combination of conditions C and MP were compared;FC-SC, FC-SMP, FMP-SC, and FMP-SMP. Differences in mouthguard thickness due to molding conditions for the first and second layers were analyzed by two-way ANOVA and Bonferroni’s multiple comparison test. Significant differences were observed among all molding conditions on the labial surface, and the thicknesses were in the order FC-SC < FC-SMP < FMP-SC < FMP-SMP. FMP-SMP was 4.67 mm thick, which was 1.39 mm thicker than FC-SC. FC-SC was the thinnest at the cusp, and a significant difference was observed between other molding conditions. On the buccal side, significant differences were observed between all conditions except FC-SMP and FMP-SC, and the thicknesses were in the order FC-SC < FC-SMP, FMP-SC < FMP-SMP. The results of this study suggested that the labial and buccal sides of laminated mouthguards could be made 1.4 and 1.2 times thicker when a molding technique that moves the model position just before formation was used for the first and second layers. The reduction in thickness was suppressed by approximately 23.2% and approximately 10.7% on the labial and buccal sides, respectively, compared with the normal molding method.

关键词： Laminated Mouthguard Thermoforming Molding Technique Thickness

Influence of Continuous Use of a Vacuum-Forming Machine for Mouthguard Thickness after Thermoforming: Effect of the Time Interval between Repeat Moldings

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Materials Sciences and Applications 2019年第4期10卷 293-301页

作者： Mutsumi Takahashi Yogetsu Bando Department of Physiology The Nippon Dental University School of Life Dentistry at Niigata Niigata Japan Bando dental clinic Ishikawa Japan

Mouthguards can reduce the risk of sports-related injuries, but the sheet material and thickness have a large effect on their efficacy and safety. This study was intended to predict the changes in thickness of molded products by clarifying the effect of the time interval between repeat moldings during the continuous use of a vacuum-forming machine. Ethylene vinyl acetate mouthguard sheets were used for thermoforming with a vacuum-forming machine. The working model was trimmed to a height of 23 mm at the maxillary central incisor and 20 mm at maxillary first molar. Five molding conditions were investigated: 1) molding was carried out after the sag at the center of the softened sheet was 15 mm (control);2) sheet heating was started 5 min after the molding of the control (AF5-Re1);3) sheet heating started 5 min after the molding of AF5-Re1 (AF5-Re2);4) sheet heating started 10 min after the molding of the control (AF10-Re1);and 5) sheet heating started 10 min after the molding of AF10-Re1 (AF10-Re2). Sheet thickness after fabrication was determined for the incisal edge, labial surface, cusp, and buccal surface using a special caliper accurate to 0.1 mm. Thickness differences of the molding conditions were analyzed by two-way analysis of variance. Significant differences between the control and AF5-Re1 were observed at all measurement points (p < 0.01), but not between the control and AF10-Re1. AF10-Re2 became thinner than AF10-Re1 (p < 0.01). Reproducible molding results were obtained by waiting 10 min between the first and second moldings, but the third molded mouthguard was significantly thinner, despite this 10 min wait interval.

关键词： Mouthguard Thermoforming Thickness Vacuum Formation Continuous Use

Difference in Surface Roughness of Ethylene-Vinyl-Acetate Sheet before and after Application of Finishing Liquid

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Materials Sciences and Applications 2018年第13期9卷 985-992页

作者： Mutsumi Takahashi Yogetsu Bando Department of Physiology School of Life Dentistry at Niigata The Nippon Dental University Niigata Japan Bando dental clinic Ishikawa Japan

Surface texture of the mouthguard affects the sense of adaptation in the athlete and further affects hygiene. Therefore, finish polishing is extremely important. The aim of this study was to investigate the difference in the surface roughness after finishing polishing of ethylene-vinyl-acetate (EVA) sheets and after application of the finishing liquid, and to evaluate its effectiveness. Total of 48 specimens of EVA (3 × 3 mm) were divided into 4 groups according to polishing condition (control = unpolished;condition A = Robinson-brush;condition B = Lisko-Fine, and condition C = Mouthguard-wheel). Polishing was performed at low speed by using a straight headpiece. The rotation speeds were 5000, 4000 and 6000 rpm for condition A, B, and C, respectively. Next, a finishing liquid was applied to each specimen. For application, a cotton swab was used, and it was applied by three reciprocations. A non-contact surface shape measuring machine was used for measuring surface roughness;the measurement range is 1.65 mm and the resolution is 0.01 nm. The arithmetic average height (Sa) was measured. The differences in the surface roughness before and 15 min after the 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, condition C, B and A, and Sa was about 0.20, 1.98, 2.92, and 4.71 μm, respectively. The degree of reduction in roughness was about 1.0 μm or more than each polished state in conditions A and B. Condition C was not significantly different before and after application. No significant difference was observed between condition B and C after application. The results of this study showed that the surface roughness decreased due to the application of the finishing liquid when the surface roughness after finish polishing was about 2.0 μm or more.

关键词： Mouthguard Ethylene-Vinyl-Acetate Surface Roughness Polishing Method Finishing Liquid

Effect of Thermal Shrinkage of Extruded Sheet on Mouthguard Thickness: Influence of Model Undercut

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Materials Sciences and Applications 2022年第1期13卷 54-62页

作者： Mutsumi Takahashi Yogetsu Bando Department of Physiology The Nippon Dental University School of Life Dentistry at Niigata Niigata Japan BANDO dental clinic Ishikawa Japan

The effectiveness and safety of the mouthguard are greatly affected by its thickness. The aim of this study was to investigate the effect of thermal shrinkage of the extruded sheet on the mouthguard thickness depending on the amount of undercut of the model. Mouthguard sheet was used a 4.0 mm thick ethylene-vinyl acetate resin manufactured by extrusion molding. The sheets were placed in the vacuum forming machine with the sheet extrusion direction either vertical (condition V) or parallel (condition P) to the model’s centerline. The working models were three hard plaster models trimmed so that the angles of the anterior teeth to the model base were 90?, 100?, and 110? (Models A, B, and C). The sheet was softened until it sagged 15 mm, and then suction was continued for 30 s. Measurement points of the mouthguard were the incisal portion (incisal edge and labial surface) and molar portion (cusp and buccal surface). The differences in the reduction rate of the thickness due to model form and extrusion direction were analyzed using two-way ANOVA and Bonferroni’s multiple comparison tests. Differences in thickness depending on the extrusion direction of the sheet were observed in Models B and C on the labial surface and in all models on the buccal surface, and the thicknesses obtained under condition P were significantly thinner than those obtained under condition V. The thicknesses of the incisal edge and the cusp were not affected by the extrusion direction. The result of this study was suggested that the labial and buccal thickness of the mouthguard was secured by placing the sheet in the extrusion direction vertical to the model’s centerline. Furthermore, it was clarified that the presence of the undercut of the model tends to increase the influence of the extrusion direction of the sheet on the thickness of the mouthguard.

关键词： Mouthguard Extrusion Molding Thickness Model Angle Undercut

Effect of Model Height and Model Position on Forming Table on Mouthguard Thickness in Thermoforming Using Circular Frame

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Materials Sciences and Applications 2021年第5期12卷 197-206页

作者： Mutsumi Takahashi Yogetsu Bando Department of Physiology The Nippon Dental University School of Life Dentistry at Niigata Niigata Japan BANDO dental clinic Ishikawa Japan

Effectiveness and safety of mouthguards are greatly affected by its thickness. The aim of this study was to clarify the effect of model height and model position on the forming table on the mouthguard thickness in thermoforming using a circular frame. Mouthguards were thermoformed using 4.0-mm-thick ethylene-vinyl-acetate sheets and a vacuum forming machine. The sheet was sandwiched between circular frames and fixed to the clamp of the forming machine. Working models were two types of hard gypsum models trimmed so that the height of the anterior part was 25 mm (Model A) and 30 mm (Model B). The model was placed with its anterior rim positioned 40 mm (P40), 30 mm (P30), 20 mm (P20), or 10 mm (P10) from the front of the forming table. Differences in the reduction rate of the thickness due to the model height and model positions were analyzed by two-way ANOVA and Bonferroni’s multiple comparison test. Differences depending on the model height were observed at P40 at the incisal edge and P30, P20, and P10 on the labial surface, and the reduction rate of the thickness was significantly smaller in Model A (P < 0.01). As the distance from the model anterior rim to the front of the forming table was smaller, the rate of the thickness of the incisal edge and the labial surface decreases became larger. The rate of decrease in the thickness of the cusp and buccal surface was the smallest at P20. This study indicated that the difference in the thickness of the single-layer mouthguard depending on the model position on the forming table is affected by the model height. However, that is only the anterior part of the mouthguard, and the difference in thickness reduction rate is less than 5%. Additionally, in order to perform stable forming, it is useful to increase the distance from the model to the frame, and it is important to position the part whose thickness is desired to be maintained in the center of the forming table.

关键词： Mouthguard Thermoforming Model Height Model Position Thickness