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BACKGROUND/AIM Mouthguards should be provided with appropriate thickness and proper fit to exert their effects. However, mouthguard thickness becomes thinner after forming. The aim of this study was to examine the effect of using a notched mouthguard sheet and forming as the heated surface of the sheet contacts the surface of the working model. MATERIALS AND METHODS The material used was a 3.8-mm-thick Sports Mouthguard. Notches with a length of 90 and 80 mm were cut into an ethylene vinyl acetate sheet 20 mm from the anterior and posterior margins and 15 mm from the right and left margins, respectively, and the sheet was compared with the original. The sheets were then formed using a vacuum former. Original and notched sheets were heated until the temperature of the sheet reached 80°C, and the non-heated surface of the sheet was sucked down over the model. Both sheets were also heated at first until the sheet temperature reached 80°C, then turned upside down, and the heated surface of the sheet was sucked down over the model. The thickness and fit of the mouthguard were measured at the central incisor and first molar. Differences in thickness and fit according to the measurement parts and the sheet conditions were analyzed by two-way ANOVA. RESULTS The thickness of the mouthguard significantly differed by the measurement parts and the sheet conditions (P

BACKGROUND/AIM The incidence of orofacial injuries and the use of mouthguards in water polo players have not been well established. The aim of this study was to determine the incidence of orofacial injuries in water polo players. Frequency of mouthguard use, the types of mouthguards used and the degree of interference with oral functions were also assessed. MATERIAL AND METHODS In this cross-sectional study, 347 water polo players completed a questionnaire about the orofacial injuries suffered in the 2015-2016 season and the experience of using a mouthguard, such as the type of mouthguard used and the degree of interference with oral functions. RESULTS In the 2015-2016 season, 57.9% of the players reported at least one orofacial injury, with mean numbers of 2.7 oral lacerations, 0.4 episodes of temporomandibular pain and 0.06 dental injuries. Among the 35 players (10.1%) who had tried a mouthguard, only four (1.2%) used it habitually. Some players had tried more than one type of mouthguard; 26 had tried the mouth-formed type; 11 the custom-made type; and 7 the prefabricated mouthguard. Custom-made mouthguards were rated as more comfortable than the mouth-formed type (P

Background/aims Previous studies have compared the thickness of the device with and without grooves. The result was a difference in thickness of the device along the groove. The aim of this study was to assess the differences in thickness of mouthguards that result from different groove shapes of ethylene vinyl acetate sheets used to make these appliances. Materials and method Mouthguards were made using a 3-dimensional printer, and produced by softening 4 mm transparent circular sheets. Four different shapes of sheets were evaluated: normal sheets, sheets with anterior V-shaped grooves, sheets with anterior A-shaped grooves, and sheets with posterior A-shaped grooves. The groove was 3 mm deep and 5 mm wide. The thickness of the appliance was assessed with respect to the anterior incisal edge, labial surface, palatal surface, posterior cusp, buccal surface, and palatal surface. The Kruskal-Wallis test was used to analyze differences in thickness among the different groove shapes. Results No significant difference was detected between the thickness of mouthguards made using sheets with grooves and that of mouthguards made using sheets without grooves (P > .05). Conclusion The presence of grooves on the sheets did not influence mouthguard thickness.

Background/aim The mouthguard (MG) is an effective device to reduce the risk of dental traumatic injuries, but the mechanical effects of wearing a MG and its design are not fully understood. The aim of this study was to evaluate the mechanical influence of wearing a MG and its palatal design on the tooth-periodontal ligament-bone complex (TPBC) by computational analysis using the finite element method. Material and methods Three-dimensional subject-specific geometry of the TPBC was reconstructed from medical computed tomography (CT) images. Two patterns of MG geometries were constructed which covered the palatal domain or not (the position of these palatal margins was set at -8 mm (pattern 1) and 4 mm (pattern 2) from the cervical line. Five cases of static mechanical analysis were conducted by changing the location of the loading points from near the cervical line to the tip of the tooth. Results Wearing a MG decreased strain concentration around the loading point and cervical domain regardless of the MG palatal design. Elastic energy in the periodontal ligament (PDL) and tooth (including enamel and dentin) decreased when the MG was worn, whereas the MG palatal design slightly affected the degree of reduction in the elastic energies. The location of the loading points remarkably affected the elastic energy in the TPBC components and the extent of its reduction due to the MG. Conclusions These findings indicated that the protection ability of the MG exerted in the restricted situations of traumatic events occurs regardless of the MG design.

Background/Aims: Mouthguards (MGs) are devices that can reduce the risks of facial trauma. However, the large variety of MG types and thicknesses raises the question of which type is the most effective and beneficial for the athletes. The aim of this study was to evaluate stress distribution in the skull, teeth, and jaws as a consequence of a direct impact. Material and Methods: Using modeling software, a human skull was modeled and a human jaw was created with all teeth inserted into the respective alveolus. The models were divided according to the MG type (custom-made or stock) and thickness (1, 2, and 4 mm). Two models without MG were evaluated with and without teeth contact. The geometries were exported to analysis software and the materials were considered ideal. Fixation occurred at the base of the foramen magnum. The load (500 N) was applied on the canine tooth with a ball. Maximum principal (MPa) and Von-Mises results were obtained. Results: Without any protection, the generated tensile stress was of greater magnitude causing more damage in the absence of teeth contact. The presence of a MG significantly reduced the generated stress in all structures, and the customized/individualized type was more efficient than stock MGs. Conclusions: In extreme situations when it is impossible to use a MG, keeping the teeth in maximum intercuspal position is less harmful. Despite this, the use of any MG is beneficial and assists in dampening the generated stress. The thicker the device, the greater the capacity for decreasing the damage in all structures. The use of individual protectors for each patient is even more beneficial for preventing trauma during at-risk activities of impact.

There appears to be much confusion or misinformation worldwide regarding mouthguards and their use in sports. In an effort to clarify where the international dental community stands on mouthguards and mouthguard research, the workshop looked at some important questions. The goal is to one day formulate consensus statements related to these questions, which will be based on current scientific evidence-based research, to motivate the international community of the importance of dentally fitted laminated mouthguards and the wearing of them by athletes of all sports. There are only five sports in the USA that require the use of mouthguards. If through workshops such as this, the importance of wearing dentally fitted laminated mouthguards can be demonstrated, then more sports may require their athletes to wear them. This article is protected by copyright. All rights reserved.

Background/Aims Fabrication of mouthguards should be performed properly. However, the appropriate heating temperature for fabricating a pressure-formed mouthguard has not been determined. The aim of this study was to examine the influence of the heating temperature on the fabrication of a pressure-formed mouthguard. Materials and methods Mouthguard sheets of 3.8 mm ethylene vinyl acetate were pressure formed on a working model at three heating temperatures: 80°C, 100°C, and 120°C. The thickness of the mouthguard was measured at the labial surface of the central incisor, and the buccal and occlusal surfaces of the first molar. The fit of the mouthguard was examined at the central incisor and first molar by measuring the distance between the mouthguard and the cervical margin of the working model. Differences in the thickness of the mouthguards according to the heating temperatures were analyzed by two-way analysis of variance, and differences in the fit were analyzed by one-way analysis of variance. Results Mouthguard thickness varied among the measured regions of the central incisors and first molars (P < .01). The greatest thickness was found at the labial surface of the central incisor and the buccal surface of the first molar in mouthguards fabricated at the heating temperature of 120°C (P < .01). Mouthguard fit varied among the heating temperatures of the central incisors, and the greatest fit was obtained in mouthguards fabricated at the heating temperatures of 100°C and 120°C (P < .01). Conclusions Heating the ethylene vinyl acetate sheet until the temperature reached 120°C was the best fabrication method to maintain the pressure-formed mouthguard thickness with proper fit. This article is protected by copyright. All rights reserved.

BACKGROUND/AIM The method used to form mouthguards should be carefully selected in order to obtain their full preventive benefits. The aim of this study was to examine the differences of mouthguard characteristics according to the forming methods. MATERIALS AND METHODS Mouthguard sheets of 3.8-mm ethylene vinyl acetate were vacuum-formed and pressure-formed on a working model. The sheets were formed when heating causing them to displace 15 mm from baseline. Mouthguard thickness was measured at the labial surface of the central incisor, the buccal surface of the first molar, and the occlusal surface of the first molar. The fit of the mouthguard was measured at the central incisor and the first molar. Differences in the thickness and fit between the vacuum-formed and pressure-formed mouthguards were analyzed by two-way analysis of variance and the Bonferroni method. RESULTS Mouthguard thickness varied between the central incisors and first molars (P

AIM The aim was to examine the influence of the heating temperature on the fabrication of vacuum-formed mouthguards. MATERIALS AND METHODS Mouthguard sheets of 3.8 mm ethylene vinyl acetate were vacuum-formed on working models at three heating temperatures: 80, 100, and 120°C. The thickness of the mouthguard was measured at the labial surface of the central incisor, and the buccal and occlusal surfaces of the first molar. Differences in the thickness of the mouthguards were analyzed by two-way analysis of variance. The fit of the mouthguard was examined at the central incisor and the first molar by measuring the distance between the mouthguard and the cervical margin of the working model. Differences in the distance between the mouthguard and the cervical margin according to the heating temperatures were analyzed by one-way analysis of variance. RESULTS Mouthguard thickness varied among the measured regions of the central incisors and first molars (P < 0.01). The greatest thickness was found at the labial surface of the central incisor and the buccal surface of the first molar in mouthguards fabricated with heating temperature of 120°C (P < 0.05). The best fit was obtained in mouthguards fabricated with heating temperature of 120°C (P < 0.05). CONCLUSIONS Heating the mouthguard sheet until the temperature reached 120°C was the best fabrication method to maintain the thickness and to obtain proper fit. It is important to control the heating temperature when fabricating vacuum-formed mouthguards.

BACKGROUND/AIM Custom-made mouthguards are fabricated on working models. However, the influence of the working model to the mouthguard characteristics has not been clearly established. The aim of this study was to examine the influence of the angle of the working model on the formation of a pressure-formed mouthguard. MATERIALS AND METHODS Mouthguard sheets of 3.8 mm ethylene vinyl acetate were pressure-formed onto working models. The angle of the working model formed by the labial surface of the central incisor and the base of the working model was set at 85°, 90°, and 95°. The thickness of the mouthguard was measured at the labial surface of the central incisor, and the buccal and occlusal surfaces of the first molar. Differences in the thickness of the mouthguards were analyzed by two-way analysis of variance. RESULTS Mouthguard thickness varied among the measured regions of the central incisors and first molars (P < 0.01). The thickness at the labial surface of the central incisor and buccal surface of the first molar was greatest for mouthguards formed using the working model with the angle set at 85° (P < 0.01). CONCLUSIONS The angle of the working model at the labial surface of the central incisor and the base of the working model should be maintained at an acute angle (e.g., 85°) to control the thickness at the central incisors and the first molars of pressure-formed mouthguards.

Background The purpose of this study was to identify changes in sheet shape during thermoforming and the effect of the model position in the molding machine on fabricated mouthguard thickness. Materials and Methods Ethylene vinyl acetate mouthguard sheets (3.8 mm thick) were used that had cross-stripes (10 × 10 mm), and the anteroposterior and bilateral lengths were used for measurements. Two forming machines were used: a vacuum- and a pressure-forming machine, and two heating conditions were investigated that defined as the time when sagging of the softened sheet was 15 mm (H-15) and 20 mm (H-20) below the clamp, and the length of each cross-stripes was measured. The area of each lattice was calculated using Bretschneider's formula to compare changes in sheet shape for each condition. Next, mouthguards were molded by forming machine where the working model was positioned under two different conditions: with the model anterior centered in the forming unit and with the model centered. The sheet thickness after fabrication was determined for the incisal and the molar portion, and dimensional measurements were obtained using a measuring device. Differences in the thickness were analyzed by two-way analysis of variance (anova). Result In both molding machines, the change in the area under H-20 was greater than H-15. While the increase in area tended to expand from the center of the sheet in concentric circles, the difference between the central and surrounding areas was only approximately 5%. For both molding machines, differences in thickness after molding due to setting position of the model were not observed. Conclusion The results showed that shape changes of the sheet during thermoforming tend to concentrically and almost uniformly expand from the center and that it is important to center the sheet and the model when positioning the model in the forming unit.

Background The goal of the present study was to examine the thickness of mouthguards molded under a variety of heating conditions to clarify suitable conditions during vacuum-pressure forming of ethylene vinyl acetate sheets. Materials and methods Mouthguards were fabricated using ethylene vinyl acetate (EVA) sheets (thickness: 4.0 mm) using a vacuum-pressure forming machine. The sheet was pressed against the working model, followed by vacuum forming for 10 s and compression molding for 2 min. Three heating conditions were investigated in which the sheet was molded when the center of the softened sheet sagged 10 mm, 15 mm, or 20 mm below the clamp (H-10, H-15, or H-20 respectively). The temperature of the sheet surface was measured using a radiation thermometer under each heating condition. The thickness of the mouthguard sheets after fabrication was determined for the incisal portion (incisal edge and labial surface) and molar portion (cusp and buccal surface), and dimensional measurements were obtained using a measuring device. Differences in thickness due to the heating condition of the sheets were analyzed by one-way analysis of variance and Bonferroni's multiple comparison tests. Results The temperature difference between the heated and non-heated surfaces was lowest under H-15. The thickness differences at incisal edge, labial surface, and cusp were determined. The thicknesses for H-10 and H-15 were greater than that for H-20, and the thicknesses for H-10 and H-15 were equivalent at all measurement points. No differences in thickness at the buccal surface were observed for the various heating conditions. Conclusion The present study demonstrated that a sagging distance of 15 mm provided the most suitable forming process. The results of the present study provide a standard heating condition for EVA sheet forming.

Aim The purpose of this study was to examine the differences of the vacuum-formed mouthguard thickness by the timing of vacuum application. Materials and methods The material used in this study was a mouthguard sheet of 3.8-mm ethylene vinyl acetate. Three conditions of the timing of vacuum application were examined: the vacuum was applied immediately, 5 s after, and 10 s after the sheet holder was lowered over the vacuum-forming stand. We measured mouthguard thickness at the labial surface of the central incisor, buccal surface of the first molar, and occlusal surface of the first molar. Differences in thickness in different regions of mouthguards formed under different timing of vacuum application were analyzed by two-way analysis of variance and Bonferroni method. Results We found that mouthguard thickness differed in different regions of the central incisors and the first molars (P < 0.01). The mouthguard thickness at the labial surface of the central incisor and buccal surface of the first molar became thinner when the vacuum was applied immediately after the sheet holder was lowered over the forming stand. The thickness at the occlusal surface of the first molar did not vary with the timing of vacuum application. Conclusions Our results suggest that the thicknesses of the labial surface of the central incisor and buccal surface of the first molar became larger when the vacuum was applied several seconds after the sheet holder was lowered over the forming stand. This finding is necessary knowledge when forming a mouthguard sheet.

Background/aim The aim of this study was to evaluate the tooth stresses and strains, shock absorption, and displacement during impact of custom-fitted mouthguards with different thicknesses. Methods Six bar-shaped specimens of the EVA were made and subjected to tensile test for elastic modulus assessment. Two-dimensional plane-strain models of a human maxillary central incisor, periodontal ligament, bone support, soft tissue, and mouthguard (MTG) were created. The mouthguards were modeled in five different thicknesses (2, 3, 4, 5, and 6 mm). One model was created without mouthguard. A nonlinear dynamic impact analysis was performed in which a rigid object hit the model at 1 m s(-1). Strain and stress (von Mises and Critical modified von Mises) distributions were evaluated, and the displacement of the mouthguard with respect to the tooth was calculated. Results The mean [SD] for the EVA elastic modulus was 18.075 [0.457] MPa. The model without mouthguard showed the highest stress values at the enamel and dentin structures in the tooth crown during the impact. For the MTG models, the location of the stress concentrations changed to the root, regardless of the MTG thickness, but maximum stresses in the enamel and dentin were lower compared with the model without MTG. Increasing the mouthguard thickness did not notably decrease the stress-strain values. Conclusion It was concluded that the use of a mouthguard promoted lower stresses and strains in teeth during an impact with a rigid object. There was no substantial difference in peak stresses and strains and in shock absorption among the different mouthguard thicknesses.

Aim The aim of this study was to examine the effectiveness of layering a second piece of ethylene vinyl acetate on the original sheet before fabrication to maintain the thickness of vacuum-formed mouthguards. Materials and methods Two methods were used to form mouthguards. In the first, a 3.8-mm ethylene vinyl acetate sheet was laminated after 3.0-mm ethylene vinyl acetate sheet was formed at the anterior teeth area. In the second, a second piece of 3.0-mm sheet was layered on the original 3.8-mm sheet in the region mounted on the anterior teeth. Mouthguard thickness at specific sites on the central incisors and first molars was measured. The differences in mouthguard thickness according to measurement regions and forming methods were analyzed by two-way analysis of variance and a post hoc test (Bonferroni method). Results Mouthguard thickness differed significantly among the measurement regions (P

The aim of this study was to investigate the influence of the thermal shrinkage to thickness of the mouthguard with the heating method by the setting position of a sheet and the working model using an ethylene vinyl acetate sheet prepared by extrusion. Mouthguards were fabricated with EVA sheets (4.0 mm thick) using a vacuum-forming machine. Two forming conditions were compared: the square sheet was pinched by the clamping frame attached to the forming machine (S); and the round sheet was pinched at the top and bottom and stabilized by the circle tray (R). The sheet was aligned to make the sheet's extrusion direction vertical (V) or parallel (P) to the midline of the working model. The following two heating conditions were compared: (i) the sheet was molded when it sagged 15 mm below the level of the sheet frame measured at the top of the post in condition S (S-0), or that sagged 10 mm in condition R (R-0) in the usual position; (ii) the sheet frame was lowered by 50 mm from the ordinary height (S-50, R-50). Postmolding thickness was determined using a measuring device. Measurement points were the incisal and molar portion. Differences in the change of thickness of mouthguards molded under different heating conditions and extrusion directions for each sheet shape were analyzed by two-way analysis of variance (anova). The results of this study showed that by lowering the height of the sheet frame, the difference of the sheet temperature of each part was reduced. Among all sheets, condition V produced under S-50 and R-50 had the largest thickness independently of shape sheet. Furthermore, thickness reduction is effectively suppressed by aligning the direction of the extruded sheet to be vertical to the midline of the model.

BACKGROUND: The aim of this study was to measure the finished thickness of a single identical 4-mm EVA mouthguard model from a large fabricated sample group and to evaluate the degree of material thinning and variations during the fabrication process. MATERIALS AND METHODS: Twenty boxes were distributed to dental technician participants, each containing five duplicated dental models (n = 100), alongside 5 × 4 mm mouthguard blanks and a questionnaire. The mouthguards were measured using electronic callipers (resolution: ±0.01 mm) at three specific points. The five thickest and thinnest mouthguards were examined using a CT scanner to describe the surface typography unique to each mouthguard, highlighting dimensional thinning patterns during the fabrication process. RESULTS: Of the three measurement points, the anterior sulcus point of the mouthguard showed a significant degree of variation (up to 34% coefficient of variation), in finished mouthguard thickness between individuals. The mean thickness of the mouthguards in the anterior region was 1.62 ± 0.38 mm with a range of 0.77-2.80 mm. This variation was also evident in the occlusion and posterior lingual regions but to a lesser extent (up to 12.2% and 9.8% variations, respectively). CONCLUSION: This study highlights variability in the finished thickness of the mouthguards especially in the anterior sulcus region measurement point, both within and between individuals. At the anterior region measurement point of the mouthguard, the mean thickness was 1.62 mm, equating to an overall material thinning of 59.5% when using a single 4-mm EVA blank. This degree of thinning is comparative to previous single operator research studies.

Prevention of orofacial injuries is one of the biggest pre-occupations in sports dentistry. The custom-fitted mouthguard is considered the best choice for fit and protection when compared to over-the-counter commercial mouthguards. However, cost and time prohibit their mass production. It is therefore imperative to have an over-the-counter true mouth-formed mouthguard with comparable properties. The present in vitro experimental study was carried out to compare the shock absorption ability of EVA laminate mouthguards with self-adapting polyolefin material mouthguards in three different anterior teeth alignments.Finite element analysis (FEA) was performed to simulate the stress distribution due to impact on the respective mouthguards. Customized pendulum device with three interchangeable standard size impact objects was used. Response of grating was monitored using a FBG interrogation system. Shift in wavelength for each impact was measured. Three standardized jaw models were subjected to a total of 72 impact strikes with three different balls on two specified sites by releasing the objects from two different heights H1 24 cm and H2 48 cm.Two-way ANOVA was applied and comparative values computed. It was found that the percentage shock absorption ability of self-adapted polyolefin mouthguard was highly significant at0.001 level in both regions. The influence of height on the shock absorption ability of both mouthguards was highly significant at P0.001. It was concluded that self-adapting polyolefin mouthguards fulfill similar protection requirement as custom-fit mouthguards and can be used for millions of athletes if properly fitted chairside by a dentist without requiring laboratory fabrication.

Purpose The purpose of this study was to investigate the differences of pressure-formed mouthguard thickness by varying the heating conditions within the proper heating temperature. Materials and methods The material used in this study was a mouthguard sheet of 3.8-mm ethylene vinyl acetate. The sheets were formed by pressure forming using a vacuum-pressure former. Three heating conditions were varied as follows: the sheet was heated until the center was displaced by 10, 15, and 20 mm from baseline. We measured the mouthguard thickness at the labial surface of the central incisor, buccal surface of the first molar, and occlusal surface of the first molar. Differences in thickness by measurement region of the mouthguards formed under different heating conditions were analyzed by two-way analysis of variance and Bonferroni's method. Results We found that mouthguard thickness varied in different regions of the central incisors and the first molars (P

Aim Custom-made mouthguard (MG) is popularly used by sports-active persons or athletes having either normo-occlussion or malocclusion to prevent dental injury. For sports-active person with malocclusion, specially designed mouthguard is often required. The purpose of this study was to make a suitable design custom-made mouthguard for sports-active person with spaced dentition by the shock absorption capability. Materials and methods Two different types of double layered mouthguards were made from a model of a sports-active person having spaced dentition with polyolefin sheets. One type was made by filling the interproximal spaces of the spaced dentition and the other type, which was devoid of interproximal space covering, without mouthguard materials (keeping space). The impact tests were carried out by a free-falling object via testing machine and a vertical rod. The strains of the dentition with mouthguard were measured by means of strain gage system to compare between two different designs of mouthguard. Unpaired t-test was carried out as statistical analysis. Result The strains of the dentition with mouthguard by filling the interproximal spaces were significantly low compared with the mouthguard by keeping spaces (P

Aim The purpose of this study was to examine differences in mouthguard thickness according to the method used to form the mouthguard sheet in a combination vacuum-pressure former. Materials and methods The material used in this study was a mouthguard sheet of 3.8-mm ethylene vinyl acetate. Three forming methods were used: vacuum-forming, vacuum-pressure-forming, and pressure-forming. The sheets were formed when heating causing them to displace 15 mm from baseline. We measured mouthguard thickness at the labial surface of the central incisor, the buccal surface of the first molar, and the occlusal surface of the first molar. Differences in thickness in different regions of mouthguards formed under different conditions were analyzed by two-way analysis of variance and the Bonferroni method. Results We found that mouthguard thickness differed in different regions of the central incisors and the first molars (P

The aim of this study was to clarify and quantify factors influencing thinning during a thermoforming using a special simulation model that has three different flat surfaces such as 0 degree, 45 degree and 90 degree against a pressurizing force. Air pressure type samples were made by EVA and acrylic resin blank. Vacuum type samples were also made by EVA. Thickness gauge was employed to measure the thickness. As results, pressure forming showed significantly larger thinning at 45 and 90 degree surfaces and smaller thinning at 0 degree surface, 36% in thinning rate by vacuum forming and 66% by the pressure forming at 90 degree surface, and 17% and 20% at 45 degree surface, and 11% and 2% at 0 degree surfaces. Thinning was increased with the increase in distance from the centre in 0 degree surface and increased with the decrease in height in the vertical surface significantly. The air pressure, the material thickness in EVA (Drufosoft) and difference in material colour did not affect thinning rate. An acrylic resin material showed approximately 10% smaller thinning than EVA (Drufosoft). To retain enough thickness of 3 mm on 90 degree surface corresponding to an incisal labial aspect for pressure laminate type, over 55% reduction is taken into consideration and at least two 3-mm-thickness materials should be laminated. 0 degree surface showed at most 2 % reduction in pressure lamination; post thermoforming occlusal thickness became almost 6 mm with a usual 3 mm plus 3 mm lamination. Therefore, careful occlusal adjustment in an actual mouthguard fabrication to achieve an appropriate 2 mm thickness on this surface should be requested.

The aim of this study was to evaluate the change in thickness of a working model mouthguard sheet due to different shape. Mouthguards were fabricated with ethylene vinyl acetate (EVA) sheets (4.0 mm thick) using a vacuum-forming machine. Two shapes of the sheet were compared: normal sheet or v-shaped groove 10-40 mm from the anterior end. Additionally, two shapes of the working model were compared; the basal plane was vertical to the tooth axis of the maxillary central incisor (condition A), and the occlusal plane was parallel to the basal plane (condition B). Sheets were heated until they sagged 15 mm below the clamp. Postmolding thickness was determined for the incisal portion (incisal edge and labial surface) and molar portion (cusp and buccal surface). Differences in the change in thickness due to the shape of the sheets and model were analyzed using two-way anova followed by a Bonferroni's multiple comparison tests. The thickness of the mouthguard sheet with v-shaped grooves was more than that of the normal sheet at all measuring points under condition A and condition B (P < 0.01). The thickness of condition B was less than that of condition A, there the incisal portion in the normal sheet and the incisal edge in the sheet with v-shaped grooves (P < 0.01). The present results suggested that thickness after molding was secured by the use of the sheet with v-shaped grooves. In particular, the model with the undercut on the labial surface may be clinically useful.

Aims: To assess rugby players' preferences for using a mouth- guard and to determine the factors contributing to the use and discontinu- ation of a mouthguard. Methods: A cross-sectional study was conducted in two rugby tournaments from 2009 to 2010. Samples were selected by convenience sampling. Participants were required to complete a self-admin- istered questionnaire, which inquired about awareness and pattern of mouthguard use, as well as reasons if discontinued. Results: Completed questionnaires were returned by 456 participants, with an estimated response rate of 77.8%. All participants were male (mean age = 22.73, SD = 3.98). Median duration of playing was 6 years, and median fre- quency was 6 h per week. Overall mouthguard use was low (31.1%, n = 142), especially for custom-fitted mouthguard (1.8%, n = 8), followed by stock mouthguard (7.7%, n = 35). Boil-and-bite type was most com- monly used (21.1%, n = 96). Of those who wore a mouthguard before, only 28% continued using it. The discontinuation rate for each type was as follows: stock, 57.1% (P = 0.032); boil-and-bite, 80.2% (P = 0.002); and custom, 37.5% (P = 0.04). Age was a significant factor for mouthguard use (P = 0.007, OR = 1.10, 95% CI = 1.03-1.17). Breathing disturbance (OR = 3.36, 95% CI = 1.17-9.72) and general discomfort (OR = 3.71, 95% CI = 1.68-8.20) were significant factors in discontinuing mouthguard use. Conclusions: The use of mouthguard was low among rugby players. Custom-made was the least worn type, possibly due to limited availability. The use of mouthguard increased slightly with age but was discouraged by breathing interference and general discomfort. Therefore, preventive effort should focus on early education and reinforcement, as well as on the improvement of wearability and accessibility.

The purpose of this study was to determine changes in the thickness of mouthguard sheets under different heating conditions during fabrication. Mouthguards were fabricated with polyolefin-polystyrene co-polymer (OS) and olefin co-polymer (OL) sheets (4.0-mm thick) utilizing a vacuum-forming machine under the following three conditions: (A) the sheet was moulded when it sagged 15 mm below the sheet frame (i.e. the normally used position); (B) the sheet frame was lowered to and heated at 30 mm below the top of the post and moulded when it sagged by 15 mm; and (C) the sheet frame was lowered to and heated at 50 mm below the top of the post and moulded when it sagged by 15 mm. The working model was trimmed to a height of 20 mm at the incisor and 15 mm at the first molar. Post-moulding thickness was determined for the incisal portion (incisal edge and labial surface) and molar portion (cusp, central groove and buccal surface). Dimensions were measured, and differences in the change in thickness due to heating condition were analysed using the Kruskal-Wallis test. Under condition C, OS and OL decreased in thickness from 0.36-0.54 mm to 0.26-0.30 mm, respectively, at the incisal portion and from 0.34-0.66 mm to 0.17-0.47 mm, respectively, at the molar portion. It may be clinically useful when moulding a mouthguard to maintain the thickness of the incisal and molar portions by adjusting the height of the sheet frame.

The aim of this study was to evaluate the influence of sheet material shape on the thickness and fit of mouthguards. Mouthguards were fabricated using ethylene vinyl acetate sheets (4.0 mm thick) and a vacuum-forming machine. The working model was trimmed to a height of 20 mm at the incisor and 15 mm at the first molar. Three forming conditions were compared: Square sheets were fabricated while being secured by the clamping frames attached to the forming machine; round sheets were fabricated while secured by a circle tray; and square sheets were fabricated while secured by a circle tray. Each condition was defined when the sheet sagged by 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 analyzed. Differences in the material thickness or the fit due to forming conditions were analyzed using one-way analysis of variance (anova). Round sheets resulted in the thinnest mouthguard at the incisor and molar region and produced the best fit. For square sheets, no significant difference in thickness was observed between the clamping frame and circle tray methods. The fit of the mouthguard at the first molar was better when using square sheets fabricated by a circle tray than those fabricated by the clamping frame. In conclusion, when molding a mouthguard using square sheets, the thickness reduction was less and fit was better with using a circle tray, which may be clinically useful.

BACKGROUND: Concussions are common among athletes, with the potential to cause memory-related, physical, cognitive, emotional, and behavioral damage. A concussion is an acceleration/deceleration injury resulting from direct and indirect biomechanical forces transmitted to the cerebral tissues. From a sports dentistry viewpoint, increased mastication muscle activity or clenching due to the presence of a mouthguard may enhance cervical muscle activity, thereby reducing damage following impact. This relationship has not been previously investigated in the context of rugby. The purpose of this study was to investigate the effect of voluntary clenching on indirect head acceleration during attack- and defense-related drills. MATERIALS AND METHODS: A total of 12 high school rugby players participated in the study. Linear acceleration of the head was measured using an accelerometer that took measurements in three axes. Masseter and sternocleidomastoid muscle activities were measured using wireless electromyography. These data were synchronized using digital video imaging software for analysis. The study protocol was approved by the Tokyo Dental College Ethics Committee. RESULTS AND CONCLUSIONS: Within the limitations of this study, the following results were obtained: the activities performed during rugby practice involved relatively small indirect head acceleration and masseter and sternocleidomastoid muscle activities. After the young male rugby players were instructed to clench their masseter muscles, a marked decrease in head acceleration was observed. Language: en

Background/Aim The purpose of this investigation was to conduct a pilot study to evaluate the use of 3D image correlation photogrammetry (3DIC) in comparing strain characteristics of three commercially available mouthguard materials in the actual form of a mouthguard. Material and methods 3DIC was used to measure strain and deformation on the surface of a mouthguard and a resin model. A computed tomographic scan of a maxilla of a patient was used to fabricate a resin test model. Three mouthguard materials were tested: conventional ethylene vinyl acetate; Proform TM, a thermoplastic material; and Polyshok TM, an EVA product containing polyurethane. Three mouthguards of each of the three materials were fabricated and fitted to the acrylic model for testing. A speckle pattern was applied to the external surfaces of each of the mouthguards. Static mechanical tests using a servohydraulic load frame at 10, 25, and 50 pounds of force were applied to the mouthguards while on the resin model. Strains were measured in both the horizontal (x) and vertical (y) axes using (3DIC). Measured strains were analysed by 4-way anova. Results For all three materials tested, the difference in strain between two measured directions (X and Y) was found to be statistically significant for all regions evaluated. The analysis indicated that each direction, region, and load was involved in a statistically significant effect (P

PURPOSE: Several methods have been used to measure the impact force absorption capacities of mouthguard materials; however, the relationships among these measurement systems have not been clearly determined. The purpose of the present study was to evaluate the impact force-absorbing capability of materials using a drop-ball system with film sensors and load cells to clarify the relationship between these two sensor systems. MATERIALS AND METHODS: Disk-shaped specimens (1, 2, and 3 mm thick) were prepared using three commercial thermoplastic mouthguard materials (Bioplast, Impact Guard, MG 21) and one experimental mouthguard material [mixture of Poly (ethyl methacrylate)]. Impact force was applied by letting a stainless steel ball drop free-fall onto the specimens and then measuring the impact load under each specimen using a film sensor system and a load cell sensor system. RESULTS: The total load measured with the film sensor system decreased with an increase in mouthguard thickness, while almost none of the transmitted impact forces measured with the load cell system were statistically different. CONCLUSIONS: The film sensor system was considered to be superior to the load cell system because the maximum stress and stress area could be determined. Language: en

A rugby player who had frequently experienced soft tissue injuries while playing rugby and wearing a conventional custom-made mouthguard came to the hospital clinic. The patient had suffered traumatic soft tissue injuries such as lip lacerations and bite trauma. Severe crowding due to ectopic maxillary and mandibular canines was observed. In response to the patient's request for better protection, a set of maxillary and mandibular mouthguards was designed: one covering the entire maxillary dentition and the other the mandibular front teeth only. The mouthguards were to be worn simultaneously. In this paper, we describe how these mouthguards were fabricated and discuss the results. The patient has experienced no injury to the stomatognathic system, including the lips, for five seasons since he began wearing this set of mouthguards. This new pairing of mouthguards appears to offer sufficient protection against injury, despite severe malalignment. We believe that this new type of paired maxillary and mandibular mouthguards has the potential to reduce sports-related dental injuries.

The purpose of this study was to examine the difference in the thickness and fit of mouthguards made by four different heating methods of the mouthguard sheet material. A Sports Mouthguard(®) of 3.8-mm thickness was used in this study. Four heating methods were performed. In one method, the sheet was heated only one side. In the other methods, one side of the sheet was heated first until the center of the sheet was displaced by 0.5 cm, 1.0 cm, and 1.5 cm from the baseline, and then turned upside down and heated. The sheets were adapted using a vacuum former when the heated sheets hung 1.5 cm from the baseline. We measured the thickness and fit of the mouthguard at the areas of the central incisor and first molar. The difference in thickness at the central incisor and first molar regions was analyzed by two-way anova. The difference in fit with different heating methods was analyzed by one-way anova. The results showed that the thickness of the mouthguard differed in the central incisor and first molar areas (P

AIM: The aim of this study was to assess the influence of custom-fit mouthguards on the aerobic performance of soccer and futsal players under 17 (U-17). MATERIAL AND METHODS: Forty players from 3 Brazilian clubs participated in the study. The athletes' aerobic performance was assessed through the 20-meter shuttle-run test. All athletes performed two tests with and without mouthguard. Two outcome variables were analyzed: (i) the total distance covered in the test (meters) and (ii) the maximum oxygen uptake (VO2 max). A questionnaire assessing the level of acceptance of mouthguards considering different parameters was administered to the athletes before the delivery of the mouthguards and after 2 weeks of use. The questionnaire used a visual analogue scale (VAS). Paired t-test was used to compare the results obtained from the shuttle-run tests and the questionnaires. RESULTS: Mouthguards did not influence the aerobic performance of the players, considering both the total distance covered in the tests and the VO2 max. Stability was the parameter with the highest acceptance. Levels of acceptance regarding breathing (P = 0.022) and communication (P = 0.002) increased after mouthguards usage. Communication had the lowest level of acceptance considering all parameters assessed. Only 10% of the players reported receiving recommendations to use mouthguards while playing football or futsal. None of the participants reported having used mouthguards before. CONCLUSIONS: The use of custom-fit mouthguards does not affect the aerobic performance of soccer and futsal U-17 players. Future studies should focus on the development of appliances with maximum protection and minimum influence on communication. Language: en

The purpose of this study was to examine the difference in the thickness and the fit of mouthguards fabricated with a vacuum-forming method of the mouthguard sheet material. The material used in this study was Sports Mouthguard (3.8 mm thickness). Two forming conditions were performed. In the first condition, the sheet was lowered over the working model after the vacuum was applied, and in the other trial, the sheet was lowered over the working model before the vacuum was applied. The sheets were formed using a vacuum former when the heated sheets hung 1.5 cm from the baseline. We measured the thickness and the fit of the mouthguard at the areas of the central incisor and first molar in both conditions. The difference of the thickness at the areas of the central incisor and first molar and the forming condition was analyzed by Two-way anova. The difference of the fit according to the forming conditions was analyzed by the Mann-Whitney U test. The results showed that the thickness of the mouthguard differed at the areas of the central incisor and first molar, but the thickness of the mouthguard did not differ according to the forming conditions. The fit of the mouthguard at the central incisor and first molar was significantly different between the forming conditions (P < 0.01 and P < 0.05). These results suggested that the fit of the mouthguard was the best without any deficiency of thickness when the vacuum was applied first and then the sheet was pressed onto the working model. These results may be useful in fabricating proper mouthguards.

Arici, Selim/0000-0001-8890-2065 WOS: 000324474200006 PubMed: 23067560 AimThe thickness of a mouthguard (MG) plays an important role in its primary function of preventing injuries. Multi-layered MGs have recently come into prominent use due to the disadvantages associated with single-layered MGs. Whereas researchers have evaluated the postfabrication thickness of single-layered MGs, the effects of fabrication procedures on multi-layered MGs are unknown. This study aimed to evaluate postfabrication thickness of various single-layered and double-layered pressure-formed MGs. Materials and methodsMouthguards were fabricated using stone models produced from impressions of a phantom model maxillary arch. A total of 50 MGs were fabricated from ethylene vinyl acetate (EVA) sheets and divided into 10 groups of five according to the sheet(s) used in fabrication. The initial thickness of each sheet was recorded prior to fabrication. Following fabrication, MG thickness was measured at seven sites per MG. Data were analyzed using independent t-tests and one-way anova followed by Tukey's test. ResultsMean reduction in MG thickness was 36-38% for single-layered MGs and 32-34% for double-layered MGs. Significant differences in thickness were seen between measured sites for all MG groups (P

AIM: Dental implant-supported reconstructions demonstrate significantly less physiological flexibility for loading and traumatic forces compared with a normal dentition because of their rigid integration with the adjacent bone. Ethylene vinyl acetate (EVA) material has become widely accepted as a mouthguard material; however, many studies indicate the necessity of improving the impact absorption ability by considering the design and developing new materials. The aim of this study was to compare the shock-absorbing ability of a novel dual component material comprising EVA and porous rubber with that of EVA alone. MATERIALS AND METHODS: Three groups of samples were tested: Group 1 = EVA (thickness, 4 mm), Group 2 = type 1 material (2-mm thick porous rubber sheet sandwiched between two sheets of 1-mm thick EVA sheets), and Group 3 = type 2 material (1-mm thick porous rubber sheet sandwiched between EVA sheets with 1 and 2-mm thickness, respectively). Shock absorption was determined by means of a hammer impact testing device equipped with strain gauge, accelerator, and load cell. RESULTS: The value of shock-absorbing ability of group 2 (40.6 ± 12.5%) was significantly higher than those of group 1 (15.6 ± 2.1%) and group 3 (21.2 ± 9.2%). The material with thicker rubber sheet showed significantly higher shock-absorbing ability compared with that of the material with thinner rubber sheet. CONCLUSIONS: The novel dual material was superior to conventional EVA material in shock-absorbing ability depending on the thickness of porous rubber, and it may be potentially effective as mouthguard material, in particular, for patients wearing implant-supported constructions.

PURPOSE: The majority of orofacial injuries affect the upper jaw, with the maxillary incisors being most prone to injury, often accounting for as many as 80% of all cases. Children with malocclusion in the anterior segment of the maxilla are more prone to traumatic injuries than those exhibiting normal occlusion, because most often the damaging force impacts directly against the maxillary anterior teeth. Hence, because of the difference of dissipation of the impact force because of the presence or absence of malocclusion, the mouthguard's shock absorption capacity would be influenced by certain factors. In the present study, a unique in vitro experiment utilizing fiber Bragg Grating (FBG) as distributed strain sensors was carried out to evaluate the shock absorption ability of laminate customized mouthguards in two different malocclusions compared with normal occlusion. MATERIAL AND METHODS: The impact was produced using a customized pendulum device with three interchangeable impact objects on typhodont models with two different malocclusions and normal occlusion from different heights. Response of gratings was monitored using an optical spectrum analyzer. Strain induced because each impact was determined from the Bragg's wavelength shifts for each grating. For every model, 12 impact strikes were measured using three different impact objects on the two specified sites by releasing the object from two different heights. RESULTS AND CONCLUSIONS: The laminated mouthguards showed significant variation in shock absorption ability when different malocclusions were compared. Hence, modifications in the original design of the laminated mouthguards should be considered for athletic competitors with malocclusion to provide adequate protection against impact. FBG sensor has shown the unique advantage of high sensitivity to strain measurement and can be used in further studies. The height of the impact is an important variable in determining the shock absorption ability of mouthguards. Language: en

Background/Aims: Snowboard riding has increased in popularity during the last decade and is also remarkable for its dramatic rise in association with serious injuries. The aim of this study was to evaluate the nature of dental or orofacial trauma in snowboard riders in Turkey, as well as to investigate if adolescent and young adult snowboard riders were aware of any protective measures. Methods: An epidemiological survey was carried out through interviews with 86 snowboard riders in Turkey. Results and Conclusions: Seventeen snowboard riders had been affected by orofacial trauma. Results revealed that all snowboarders were aware of helmet protection whereas 50 out of 86 (58%) reported that they used them. It should be concluded that from the moment a youngster begins to practice snowboard riding, (s)he should be encouraged to wear a helmet and a properly fitted mouthguard as part of the necessary protection for them to safely enjoy their sport. © 2010 The Authors. Journal compilation © 2010 John Wiley & Sons A/S.

The objective of this study was to compare the impact energy absorption of three mouthguard materials in three environments. Thirty specimens with 12.7 cm x 12.7 cm x 4 mm dimensions were prepared for each material: ethylene vinyl acetate (EVA, TS Dental and Plastics), Pro-form (Dental Resources Inc), and PolyShok (Sportsguard Laboratories). Ten specimens of each material were conditioned for 1 h at 37 degrees C in three environments: dry (ambient) condition, deionized water and artificial saliva. Specimens were impacted at 20 mph by a 0.5-inch diameter indenter containing a force transducer (Dynatup Model 9250 HV, Instron Corp), based upon ASTM Standard D3763. Energy absorption was determined from the area under the force-time curve during impact (approximately 5 or 7 ms depending on the material). Groups were compared using anova and the Tukey test. Energy absorption values, normalized to specimen thickness (mean +/- SD in J mm(-1)), were: (i) Dry: EVA 4.73 +/- 0.27, Pro-form 3.55 +/- 0.25, PolyShok 6.32 +/- 0.24; (ii) DI water: EVA 4.82 +/- 0.40, Pro-form 3.78 +/- 0.33, PolyShok 5.87 +/- 0.38; (iii) Artificial saliva: EVA 5.63 +/- 0.49, Pro-form 4.01 +/- 0.54, PolyShok 6.37 +/- 0.55. PolyShok was the most energy-absorbent material in all three environments. EVA was significantly more impact resistant than Pro-form in all three environments. EVA and Pro-form performed significantly better after saliva conditioning than dry or water conditioned, but PolyShok did not show any difference in energy absorption when conditioned in any of the three environments. Characteristic deformation patterns from impact loading were observed with an SEM for each material. The superior energy absorption for PolyShok is attributed to the polyurethane additive.

Dental trauma is a common consequence of sports practice to which emergency treatment is critical. The purpose of this study was to evaluate the knowledge of sports participants about dental trauma procedures, particularly tooth avulsion. A specific questionnaire concerning concepts, experiences and behaviors after dental trauma and the use of mouthguard was standardized and validated with 80 people. The validated questionnaire was then distributed to 310 sports participants. The results showed that 28.4% had experienced a kind of dental trauma; 42.6% would look for a dentist for treatment; 51.7% reimplanted or would reimplant the avulsed tooth; 6.5% would maintain the avulsed tooth in milk. Although 47.4% of the participants were aware of the possibility of accidents during sports practice, only 13.9% reported to use a mouthguard. This study showed an overall lack of knowledge of sportsmen and sportswomen with regards to tooth avulsion, thus reinforcing the need for educational campaigns to improve the immediate emergency treatment of tooth avulsion.

– Reports of injuries caused by kickboxing, one of the contact sports that potentially causes a large number of injuries, are relatively rare. Wearing a mouthguard is obligatory in kickboxing, but the association between maxillofacial injuries and the quality of mouthguards has not been described thus far. In this article, we present a case of mandibular fracture in a 25-year-old male, who was injured during kickboxing despite wearing a mouth formed mouthguard.

This case report describes a lateral luxation of an upper incisor in a 19-year-old non-professional boxer. The tooth displacement gradually worsened over several months because the boxer received repeated blows to the head without using a mouthguard. Being a chronic dental trauma, rather than an acute lateral luxation, this case had several unique features: the labial plate of the alveolar bone was penetrated, the root apex was free in the vestibulum, the tooth was mobile (second degree) and radiographs revealed bone resorption. This case emphasized the need for a mouthguard to be used even with amateur boxing. The dental practitioner should educate his sportsmen-patients of the risk of sport-related dental trauma and the benefit of a mouthguard.

Orthodontic appliances are one of the major risk factors for traumatic injuries during sports events. As it is difficult to take precise impressions with orthodontic appliances, fabricated custom-made mouthguards (MGs) often have poor retention or are too tight causing the disturbance of orthodontic treatments. The purpose of this article is to describe a method for custom-made MG fabrication using sheet and tube materials, with which better MG retention and rigidity as well as pressure control to the orthodontic appliances can be easily achieved.

The objective of the present study was to describe the occurrence of orofacial, particularly dental injuries in basketball, and to survey the athletes' awareness concerning the use of mouthguards during basketball training and competition. A pilot questionnaire was designed and tested with basketball players. Two hundred and thirty-six male athletes were surveyed. Seventy-seven players were professional players. Exactly 80.6% professionals and 37.7% semi-professional athletes had an experience of oral soft tissue laceration and dental injuries in basketball practice. The difference between the two groups is significant. The incidence of dental and oral injuries was related to the length of training time. About 59% of the athletes ranked the risk of orofacial and dental injury in basketball as medium. Although the awareness of mouthguards among the basketball players was very high (80.1%), only one of them had used the custom-made mouthguard. Most of the athletes gained the knowledge about mouthguards from foreign players (33.5%), media (24.8%) and teammates/classmates (24.3%). The influence of dentists was very weak. Athletes should be informed about the high risk of oral injuries when participating in contact sports. Dentists should play a more significant role in the program of promoting mouthguard use to prevent the occurrence of oral injury in sport participation.

– Objectives: The purpose of this study was to measure the comfort, wearability, physiological effects and its influence on athletes’ physical performance, of custom-fitted compared with self-adapted mouthguards (MGs). Methods: Eleven rugby players were put under specific efforts similar to those of the competition. Each player made three consecutive tests randomly wearing a commercially available ‘boil-and-bite’ self-adapted mouthguard (MG2), a custom-fitted mouthguard (MG3), and no mouthguard (reference). Forced expiratory air volume at 1 s (FEV1), expiratory flow rates peak (PEF), forced vital capacity (FVC), rebound (RB) jump 15 s, and counter-movement jump (CMJ) were measured on each player before and after the training exercise tests. Subjective evaluations by means of a visual analog scale (VAS) questionnaire took place. Comforts, adaptability, stability, tiredness, thirst, oral dryness, nausea, ability to talk, breathe, and drink were evaluated. Results: The wearing of the self-adapted MG showed significant improvement in PEF (P

The purpose of the study was to examine the compliance of children wearing their mouthguards, and to evaluate socio-environmental factors that impact upon the usage of the device. Eighty children attending the student clinic of the Hadassah School of Dental Medicine received mouthguards free of charge. One year later, 69 participants and their parents answered a survey aimed at gaining information regarding compliance and comfort when wearing the mouthguard correlated with gender, ages of parents and child, number of siblings, position of child in the family, socio-economic status, education of parents and past dental injuries of siblings or parents. Twenty-nine percent of the children never wore the mouthguard, 32% wore it sometimes, 15.9% wore it when necessary at the beginning but stopped after one month and 23.2% wore the mouthguard whenever needed. About 68% of the participants still possessed the mouthguard one year after receiving it, 44.9% reported that they did not wear the mouthguard because they forgot and 42% reported that the reason for not wearing the appliance was because it was not comfortable. Seventy-seven percent of the parents were not aware of the existence of this appliance prior to this study. In addition, 47.9% stated that dentists had not offered such treatment to them in the past, 20.8% indicated that their child had never possessed a mouthguard before due to its significant expense and 39.6% stated that they would not invest in this treatment in the future because their child would not wear the appliance. Boys were more comfortable wearing the mouthguard than girls. The younger the child and the later s/he was in the sibling order of the family, the more likely s/he was to lose the mouthguard. Language: en

The purpose of this study was to clarify the influence anterior occlusion, of mouthguards, has on protecting against a direct collision to the maxillary anterior teeth. In other words, the support mandibular dentition has when wearing a mouthguard. Two types of mouthguards were used for this study, one with an appropriate anterior occlusion or a mouthguard with positive anterior occlusion (MGAO+) and another which was a single-layer mouthguard lacking the same occlusion or a mouthguard with negative anterior occlusion (MGAO-) but with the same thickness on the buccal side. The instruments used for testing were a pendulum-type impact device with two interchangeable impact objects (a steel ball and a baseball), with a plastic jaw model having artificial teeth. Four testing conditions were observed: one with the jaw open without a mouthguard (Open NoMG), the second with the jaw clenching (loaded with 30 kg weight) without a mouthguard (Clench. NoMG), the third with the jaw clenching with MGAO- (Clench. MGAO-) and the last with the jaw clenching with MGAO+ (Clench. MGAO+). The results are as follows: both types of mouthguards showed the effects in reducing the distortion of the teeth. However, the effect was significantly obvious (steel ball = about 57% shock absorption ability, baseball = about 26%) in the mouthguard with anterior occlusion or support by lower dentition through mouthguard (Clench. MGAO+) than Clench. MGAO-. Thus, the influence of anterior occlusion of mouthguards or the support of mandibular dentition through wearing a mouthguard (MGAO+) is indispensable in reducing the impact force and tooth distortion. The results of this research should further contribute to the establishment of guidelines for safer mouthguards.

The thermoforming process involves the heating of plastic sheets to a critical temperature followed by the shaping of the heated material into a three-dimensional structure. Given that custom-fabricated mouthguards are produced using the thermoforming process, the adaptation of plastic sheets to a stone model of the dentition is likely to be affected by the ability of the mouthguard material to be heated. The purpose of this study was to establish if material color affected the adaptation and fit of custom-made mouthguards. Twelve stone models were used in this investigation. Five mouthguards were produced using each model. These mouthguards were made using clear-, white-, black-, blue- and green-colored ethyl vinyl acetate. The force required to remove the various colored mouthguards from the corresponding stone models was determined using a strain gauge housed within a specially designed apparatus. Each of the mouthguards were tested three times at two different angles of pull -45 degrees and 90 degrees . Statistical tests performed using the average amount of force required for mouthguard removal revealed an angle by color interaction. Post hoc analyses revealed that the mean force required to remove the clear-colored mouthguards from their respective stone models was significantly less than the force required to pull away blue-, black- and green-colored mouthguards. This difference between clear- and dark-colored mouthguards was observed at both angles tested with the exception of the black mouthguard which differed from the clear-colored mouthguard only when removed at an angle of 90 degrees . The results of the present study indicate that by using dark-colored mouthguard material, one can achieve superior adaptation and thus produce a more firmly fitting mouthguard.

Inline skating belongs like ice hockey, rugby, and boxing to sporting activities with high-risk of suffering tooth accidents. Because of high velocity and loss of balance, especially on uneven ground, the injury potential in inline skating is higher. The objective of this work was to conduct a comparative study between Switzerland and Germany. The questions focussed on the frequency of tooth accidents, their prevention by mouthguard and the level of information about emergency measures after dental trauma and the resulting consequences for athletes. Using a standardized questionnaire totally 612 individuals, 324 men and 288 women, in two countries belonging to three different divisions (fun, fitness and speed) were surveyed. Fifty-six (9.2%) of these 612 interviewees have already experienced a tooth injury while inline skating. More than half of all interviewed players (68.3%) were aware of the possibility of replanting avulsed teeth. Only 32.4% were familiar with the tooth rescue kit. Just 65.4% knew mouthguard and only 1.9% of those athletes (n ¼ 12) wore a mouthguard while inline skating. The results show that the area of inline skating requires more information about preventing dental trauma through sports associations and dentists.

There is some concern regarding the amount of material thinning that occurs during the fabrication of custom-fabricated mouthguards. It is unclear if this thinning is merely a consequence of the fabrication process or related to other factors such as jaw size. Thus, the purpose of this study was to evaluate the contribution that various dimensional characteristics of the dental arch and the height of the stone model would have on mouthguard thinning. Fifteen subjects participated in this investigation. Alginate impressions from each subject were used to produce three replicas of the maxillary dentition with only the height of the base varying amongst them. The total height of the three models were 20, 25, and 30 mm. A single mouthguard was produced using each of the stone models. The material thickness of the mouthguard was assessed at the labial and occlusal surfaces. Additionally, the dimensions of the stone models were documented. Pearson product moment correlation coefficients were calculated to determine the linear relationship between material thickness and (i) the height of the stone models, (ii) the arch length and (iii) the area covered by the stone model. Statistical tests performed using the mean thickness values collected from the incisors and canines revealed a high negative correlation between the height of the stone model and material thickness (r = -0.82). In addition, a low to moderate positive linear correlation was noted between arch length and occlusal thickness at the molars (r = 0.57) and between the area of the stone model with the occlusal thickness (r = 0.49). The results of the present study indicate that the height of the model used to fabricate custom mouthguards should be kept as low as possible but still allow for the production of a properly fitting mouthguard.

Although it is widely accepted that mouthguards decrease the incidence of dental injuries, there is a controversy among sports medicine professionals as to the effectiveness of mouthguards in decreasing the incidence or severity of sports- related cerebral concussion (SRCC). While some experimental data suggest that this may be the case, there exist a number of reports suggesting that mouthguards do not serve this purpose. These conclusions have been drawn, however, without actually measuring the extent of neurocognitive dysfunction in athletes following sports-related concussion. The purpose of this study was to determine whether mouthguard use reduces the neurocognitive and symptomatic impairments that follow an injurious episode of SRCC. Preseason baseline data were collected as part of an ongoing clinical program that uses a computerized neurocognitive test to assess various faculties of brain function and symptoms reported at the time of testing. Follow-up testing from 180 student- athletes who had sustained an SRCC was analyzed for the purpose of this study. These athletes were separated into one of two groups: those who reported using mouthguards and those who did not. Neurocognitive testing was accomplished using the Immediate Post-Concussion and Assessment Test (ImPACT). Results suggest that neurocognitive deficits at the time of the athletes' first follow- up assessment did not differ between mouthguard users and non- users, suggesting that mouthguard use does little to reduce the severity of neurocognitive dysfunction and onset of symptoms following sports-related head trauma. However, an interesting finding in this study was that athletes experienced significantly lower neurocognitive test scores and reported higher symptom scores following SRCC regardless of mouthguard use. This emphasizes a thorough clinical evaluation of athletes that have sustained an SRCC. Although it was found in this study that mouthguard use does not decrease the severity of concussion, it is important to note that the use of mouthguards is paramount in reducing maxillofacial and dental trauma and their use should continue to be mandated by athletic associations and supported by all dental and sports medicine professionals.