An in vitro study of the efficacy of mouthguard protection for dentoalveolar injuries in deciduous and mixed dentitions

Changes in oral functions and speech when using custom-fitted mouthguards: An uncontrolled before-and-after study

BACKGROUND/AIM

Mouthguards are crucial for protecting athletes against orofacial injuries, yet concerns persist regarding their potential impact on oral functions. This study aimed to investigate the effects of sports mouthguards on oral functions and speech over time.

MATERIAL AND METHODS

Thirty national rugby players received custom-fitted mouthguards. Questionnaire responses and speech recordings were collected before mouthguard use and at various intervals after using mouthguards: immediately, 1 week, 2 month, and 6 months. Spectrographic analysis was performed to measure voice onset time (VOT) for /p, b, t, d/ phonemes. Questionnaire responses were assessed with Friedman's test, while VOT changes were examined using one-way repeated measure analysis of variance.

RESULTS

Compliance with mouthguard use improved during training and competitions, with consistent wear reported during matches. Over time, speaking difficulties and lisping decreased significantly (p < .001). The perception of nausea improved (p < .001), stabilizing after 1 month (p = .414). Sensations of bulkiness declined (p < .001). Mouth dryness reduced steadily, with no occurrences reported by all players by the end of the study. None of the participants reported bad breath, ulcers, or redness in the mouth. VOT changed immediately after wearing mouthguards (p < .001), gradually regressing toward the baseline, although not completely reaching it. Players held a favorable view of mouthguard use, with comfort and support for mandatory use increasing over time.

CONCLUSIONS

Custom-fitted mouthguards do not lead to significant long-term disruptions in oral functions. Athletes generally adapt to mouthguard use, reporting improved comfort and greater support for their use.

Effectiveness of hard inserts in sports mouthguards: a systematic review

Objectives To improve the protective capacity of conventional ethylene-vinyl acetate mouthguards, some authors have suggested reinforcement with a hard material to distribute impact energy more widely. The research question for this systematic review was: 'does the inclusion of a hard insert in mouthguards improve the protection of anterior teeth from a direct blow?'Data sources Three bibliographic databases (PubMed/Medline, Ovid/Embase and the Cochrane CENTRAL databases) were searched up to 20 February 2021. Additional searches included hand searching of key articles and journals.Data selection A systematic search of the literature included studies where the intervention was the incorporation of hard material into sports mouthguards and where the comparator was conventional mouthguard material. Eligibility required the use of anatomical specimens or anatomical analogues which included or represented anterior maxillary teeth. Twelve eligible publications were identified.Data extraction Data extraction was first carried out independently by two reviewers. Discrepancies were resolved by discussion.Data synthesis Results of individual studies were conflicting and methodological diversity created difficulty in making a synthesis of results. All studies employed low-energy impacts that did not represent the potentially high-energy impacts encountered in sport.Conclusion The efficacy of hard inserts in sports mouthguards has not been demonstrated.

The potential of statistical shape modelling for geometric morphometric analysis of human teeth in archaeological research

This paper introduces statistical shape modelling (SSM) for use in osteoarchaeology research. SSM is a full field, multi-material analytical technique, and is presented as a supplementary geometric morphometric (GM) tool. Lower mandibular canines from two archaeological populations and one modern population were sampled, digitised using micro-CT, aligned, registered to a baseline and statistically modelled using principal component analysis (PCA). Sample material properties were incorporated as a binary enamel/dentin parameter. Results were assessed qualitatively and quantitatively using anatomical landmarks. Finally, the technique’s application was demonstrated for inter-sample comparison through analysis of the principal component (PC) weights. It was found that SSM could provide high detail qualitative and quantitative insight with respect to archaeological inter- and intra-sample variability. This technique has value for archaeological, biomechanical and forensic applications including identification, finite element analysis (FEA) and reconstruction from partial datasets.

Behavior of mineral trioxide aggregate apical plugs and root fillings under cyclic loading

AIM

The aim of the present study was to develop a methodology for constant monitoring of the resistance to fluid flow during functional loading and to then compare the efficacy of 4-mm mineral trioxide aggregate (MTA) apical plugs and full-length MTA root fillings.

METHODS

The root canals of 24 single-rooted teeth were instrumented and assigned into two groups: group 1 (filled with a 4-mm MTA apical plug and gutta percha) and group 2 (filled with MTA to cementoenamel junction level). All teeth were subjected to stepwise cyclic loading with a constant simulated interstitial pressure of 25 cm H₂ O applied apically. A Flodec machine (De Marco Engineering, Geneva, Switzerland) constantly monitored the rate and direction of fluid flow. Student's t-test, Kruskal-Wallis test, Fisher's exact test, and Newcombe-Wilson test were used for statistical analysis, with P < 0.05.

RESULTS

Crown fractures occurred in 21 teeth with no change in the rate of fluid flow. Three teeth (filled with full-length MTA) showed sudden change in the rate of fluid flow through the root canal after cyclic loading.

CONCLUSIONS

The methodology reliably monitored fluid flow during cyclic loading. There was no difference between a 4-mm MTA apical plug and full-length MTA root filling after cyclic loading using a dynamic fluid-flow monitoring technique.

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

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

Difference in vacuum-formed mouthguard thickness according to heating condition

AIM

The purpose of this study was to examine the differences of the vacuum-formed mouthguard thickness by the heating condition 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 vacuum forming using a vacuum-pressure former. Three heating conditions were prepared: The sheet was heated until the center was displaced by 10, 15, and 20 mm from baseline. 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 heating conditions 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 incisal (cusp) region was thinner than the cervical region. There was statistically significant difference among the heating conditions at the buccal surface of the first molar (P < 0.01), and the thickness became larger as the sheet was heated. Mouthguard thickness at the labial surface of the central incisor and occlusal surface of the first molar did not differ among the three heating conditions.

CONCLUSIONS

Our results suggest that the best heating condition within the proper temperature was the condition that the sheet was heated until its center displaced by 20 mm. This finding is necessary knowledge when forming a mouthguard sheet.

Thickness and fit of mouthguards according to heating methods

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 < 0.01 or P < 0.05), but not with the heating methods. The fit of the mouthguard at the central incisor and first molar areas was significantly different among the heating methods (P < 0.01 and P < 0.05). These results suggested that the fit of the mouthguard was superior when the heated surface of the sheet contacted the surface of the working model. This finding may help to fabricate accurate mouthguards.

Attitudes towards the use of mouth and face guards in Swedish ice hockey: part 2. Results

BACKGROUND/AIM

The yearly cost of sports injuries, which affects Swedish society, is estimated to 3 billion SEK (460 million USD). Injuries in ice hockey represent at least 270 million SEK (42 million USD). Despite the high number of injuries, mouth and face guards are rarely used in Swedish ice hockey. The major aim of this study was to examine the attitudes of mouth and face guards in two ice hockey clubs in Sweden (one elite and one division 3 club). A second purpose was to determine why some players use mouth and face guards, while others do not. A third goal was to present a material that ice hockey clubs could use for further discussions.

MATERIALS AND METHOD

A phenomenographic analysis of focus groups interviews.

RESULTS

The phenomenographic analysis of the data resulted in 12 categories. Within each category, issues, activities and engagement of the participants were described. Further, similarities and differences in the discussions between the elite club and the division 3 club were described. The following categories were found to engage the participants the most: 'Ice hockey is a high-velocity collision sport in which injuries are expected', 'Attitudes towards personal protection guards' and 'Suggested measures'.

CONCLUSIONS

The participants were aware of the risk of playing ice hockey, but they know little about the consequences of a dental injury. Although ice hockey players wish to protect themselves, they refuse to accept just any mouth or face guard. Through the discussions about reducing dental and jaw injuries by routine use of protection devices, many reform proposals were presented that could be useful in future discussions.

An analysis of pattern of dental injuries after fall accidents in 0- to 2-year-old children - does the use of pacifier at the time of injury make a difference?

AIM

To assess the relation between type of traumatic injury and use of pacifier at the time of a fall accident in 0- to 2-year olds.

MATERIAL AND METHODS

The study draws on data from the database on traumatic dental injuries at the Department of Oral and Maxillofacial Surgery, Copenhagen University Hospital.

RESULTS

The study includes 1125 patients ≤ 2 years of age, representing a total of 1886 injuries. A total of 176 patients had fallen while using a pacifier, whereas 949 children suffered a fall without using a pacifier. In the pacifier group, 11.9% had crown fractures compared with 20.0% of children who had fallen without a pacifier (P = 0.012). Tooth displacement (lateral luxation, extrusion or avulsion) was relatively more frequent in children falling with a pacifier compared to children falling without a pacifier (64.8%vs 54.8%; P = 0.014). Furthermore, soft tissue injury was less frequent among the former (28.4%vs 38.3%; P = 0.013).

CONCLUSIONS

Injuries occurring while using a pacifier tend to be tooth displacement rather than fractures. This is in accordance with the theoretical consideration that a blunt impact tends to favour displacement, whereas a sharp impact tends to favour fractures of the hard dental tissues.

[Intubation-linked dental injuries. Relevance of individually adaptable tooth protection models]

BACKGROUND

Tooth damage during anaesthesia could be reduced by using tooth protectors during endotracheal intubation. The effectiveness of different models was investigated using an upper jaw model.

METHOD

A total of 6 individual adaptable dental protectors (Endoragard and Camo, with wax or silicone filling, respectively, Beauty pink dental wax with and without tissue inserts) were examined in three different categories. The upper jaw was covered with each dental shield and then loaded with a force of 150 N via a blade of a laryngoscope. Subsequently, force reduction was measured in axial as well as horizontal directions. Furthermore, the reduction in oral view was determined by measuring the thickness of each dental shield with a micrometer.

RESULTS

The combination of Camo and silicone achieved the maximum horizontal force reduction value (39.2 N). Endoragard and silicone achieved the best axial value (21.6 N). Beauty pink wax had the thinnest dental shield (2.8 mm), whereas the combination of Camo and silicone gave the most limited view inside the oral cavity (3.8 mm).

CONCLUSION

Preformed dental shields are useful for reducing the force applied to the teeth and potentially reducing the probability of tooth damage during laryngoscopy. However, the shield with the highest force reduction capability is relatively large and expensive which makes general use almost impossible. The model Beauty pink was slightly less force reducing and could be considered as an inexpensive and yet effective tool for clinical assignment.

Impact energy absorption of three mouthguard materials in three environments

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, T&S 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.

Replantation of an immature permanent central incisor following pre-eruptive traumatic avulsion

Tooth avulsion represents 0.5-16% of traumatic injuries. Avulsion of a pre-eruptive left permanent maxillary incisor in a 6-year-old boy is presented. The immature tooth was replanted after rinsing with saline following 10 min dry extra-oral time. This case report describes treatment and a 2-year follow-up of the tooth. During the follow-up period, continuation of root development, pulp revascularization, and irregular dentin formation were demonstrated. The tooth is vital, functional, and esthetic. To the best of our knowledge, no such case of replantation of a pre-eruptive tooth has been reported previously.

Mouthguards in Sport Activities

Three systematic reviews were conducted on: (i) the history of mouthguard use in sports; (ii) mouthguard material and construction; and (iii) the effectiveness of mouthguards in preventing orofacial injuries and concussions. Retrieval databases and bibliographies were explored to find studies using specific key words for each topic. The first recorded use of mouthguards was by boxers, and in the 1920s professional boxing became the first sport to require mouthguards. Advocacy by the American Dental Association led to the mandating of mouthguards for US high school football in the 1962 season. Currently, the US National Collegiate Athletic Association requires mouthguards for four sports (ice hockey, lacrosse, field hockey and football). However, the American Dental Association recommends the use of mouthguards in 29 sports/exercise activities. Mouthguard properties measured in various studies included shock-absorbing capability, hardness, stiffness (indicative of protective capability), tensile strength, tear strength (indicative of durability) and water absorption. Materials used for mouthguards included: (i) polyvinylacetate-polyethylene or ethylene vinyl acetate (EVA) copolymer; (ii) polyvinylchloride; (iii) latex rubber; (iv) acrylic resin; and (v) polyurethane. Latex rubber was a popular material used in early mouthguards but it has lower shock absorbency, lower hardness and less tear and tensile strength than EVA or polyurethane. Among the more modern materials, none seems to stand out as superior to another since the characteristics of all the modern materials can be manipulated to provide a range of favourable characteristics. Impact studies have shown that compared with no mouthguard, mouthguards composed of many types of materials reduce the number of fractured teeth and head acceleration. In mouthguard design, consideration must be given to the nature of the collision (hard or soft objects) and characteristics of the mouth (e.g. brittle incisors, more rugged occusal surfaces of molars, soft gingiva). Laminates with different shock absorbing and stress distributing (stiffness) capability may be one way to accommodate these factors.Studies comparing mouthguard users with nonusers have examined different sports, employed a variety of study designs and used widely-varying injury case definitions. Prior to the 1980s, most studies exhibited relatively low methodological quality. Despite these issues, meta-analyses indicated that the risk of an orofacial sports injury was 1.6-1.9 times higher when a mouthguard was not worn. However, the evidence that mouthguards protect against concussion was inconsistent, and no conclusion regarding the effectiveness of mouthguards in preventing concussion can be drawn at present. Mouthguards should continue to be used in sport activities where there is significant risk of orofacial injury.

Using mouthguards to reduce the incidence and severity of sports-related oral injuries

BACKGROUND

This report reviews the available literature on the types and properties of athletic mouthguards, current fabrication methods and the role of mouth protectors in reducing the incidence and severity of sports-related oral injuries.

OVERVIEW

For more than 50 years, the American Dental Association has promoted the protective value of wearing properly fitted mouthguards while participating in athletic or recreational activities that carry a risk of dental injury. Safety is essential to maintaining oral health, and a properly fitted mouthguard can minimize the risks of sustaining oral injuries during participation in sports.

CONCLUSIONS

The dental literature supports the use and protective value of mouthguards in reducing sports-related injuries to the teeth and soft tissues. Dentists are encouraged to educate patients regarding the risks of oral injury in sports, fabricate properly fitted mouthguards, and provide appropriate guidance on mouthguard types and their protective properties, costs and benefits. Further studies addressing the effectiveness of currently available mouthguard types and population-based interventions for reducing oral injuries are recommended.

CLINICAL IMPLICATIONS

Participants in sporting and recreational activities are often susceptible to oral injury. To reduce the incidence and severity of sports-related oral trauma, the use of a properly fitted mouthguard is recommended in any athletic or recreational activity that carries a risk of injury.

Comparison of forces transmitted through different EVA mouthguards

Athletic mouthguards have been recommended for decades with varying levels of athlete acceptance. Issues related to compliance center around the ability to breath and speak while wearing the mouthguards. Fabrication techniques have changed over time to a two-layer ethylene vinyl acetate mouthguard fabricated on a high-pressure machine. The reported ideal thickness of these mouthguards has been somewhat variable depending on the sport and anticipated level of risk. Recent research however, has identified 4 mm as the optimal thickness of EVA. In this study an acrylic dental cast was fabricated and mounted to a drop impact fixture. Mouthguards of varying ply, thickness and palatal coverage were fabricated and tested in the fixture. Strain gauges and load cells were used to evaluate the effect of ply, thickness, and palatal coverage on the ability of these mouthguards to minimize transmitted forces. The purpose of this study was to identify those variables of mouthguard construction that will minimize the overall transmitted force of impact to the anterior dentition.

Dynamic finite element analysis of the human maxillary incisor under impact loading in various directions

The aim of this study was to investigate fracture patterns occurring when a human upper central incisor is subjected to impact loadings at various angles. A two-dimensional finite element (FE) model of the maxillary incisor and surrounding tissues was established. The structural damping factor for the tooth was then calculated and assigned to the model. Dynamic FE analysis was performed to stimulate the associated impacts. Time-dependent traumatic forces at 0 degrees, 45 degrees, and 90 degrees labially to the long axis of the tooth were applied to the model. Von Mises's equivalent stress contours within the FE models were calculated. Our results indicated that tooth damping lagged behind peak stress by 0.05 ms. In addition, we found that impact direction played an important role in terms of outcome for the fractured incisor. These results can, in part, explain the mechanisms underlying the alternative outcomes when upper incisors are subjected to impact.

Damping effects on the response of maxillary incisor subjected to a traumatic impact force: a nonlinear finite element analysis

OBJECTIVES

The aim of this study was to evaluate the effects of damping on stress concentration in an impacted incisor.

METHODS

Damping ratios of maxillary incisors were tested using an in vivo modal testing method. A finite element model of the upper central incisor was established for dental trauma analysis. To assess the effect of damping properties on induced stresses in the traumatized incisors, equivalent stresses in the finite element model with various damping ratios were calculated for comparison. The mechanisms of cushioning properties of the upper incisors on traumatic injuries were assessed by profiling the stress distributions in the incisor model sequentially with time.

RESULTS

The measured damping ratio of maxillary incisors was 0.146+/-0.037. When the incisor was subjected to an impact force, high stresses were concentrated at the labial and lingual incisor edges, cervical ridge, and the area around root apex. When the damping ratios of the incisor model were set at 10- and 50-fold of the measured values, the peak stresses induced near the impact site of the incisor model were reduced from 24.0 to 23.2 and 15.9 MPa, respectively. On the other hand, the peak stress lagged and the stress existence period increased when the damping properties were taken into consideration.

CONCLUSIONS

Damping properties of teeth provide protection to the tooth during traumatic injury by decreasing the peak stress magnitude due to release of strain energy over a longer period.

Nigerian dentists' knowledge and attitudes towards mouthguard protection

The objective of this study was to assess the knowledge and attitudes of Nigerian dentists towards mouthguard protection. A pre-tested 15-item, one-page questionnaire was distributed to 185 dentists practising in different parts of the country with government hospitals or private establishments, by 'hand-delivery' system. Filled and returned forms were 170 (response rate of 92%). The period of the survey was between April and August 2003. Dental graduates from the different dental schools in the country responded to this survey. About 49% of the respondents indicated having only classroom lectures on mouthguards during their undergraduate trainings, 11% said they had some laboratory sessions in addition while no form of education on mouthguards was received by 40%. About 82% had never recommended mouthguard protection for athletic patients, and the major reason was no formal training in the subject. Only 58.5% were familiar with the different types of mouthguards, 75.9% would not be able to supervise or fabricate mouthguards and 50.6% would prefer custom-made mouthguard for their athletic patients. About 84% felt the current training on mouthguards in Nigerian dental schools is inadequate. Over 98% agreed that mouthguard usage in contact sports should be encouraged with the involvement of the dentists. The knowledge and attitudes of the respondents towards mouthguard protection did not vary significantly across years of postqualification from dental schools as well as the professional status of the dentists (P > 0.05). Although Nigerian dentists support mouthguard protection in contact sports and want to be involved in the provision of mouthguards for athletes, their knowledge of the protective device is inadequate. There is need for attention to be given to this subject in the undergraduate curricula of our dental schools.

Are all mouthguards the same and safe to use? The influence of occlusal supporting mouthguards in decreasing bone distortion and fractures

The safety benefits of mouthguards have been demonstrated in many studies, with many authors and sports dentists strongly recommending the wearing of mouthguards. However, wearing a mouthguard with incorrect occlusion might cause a variety of problems. It comes as no surprise that a traumatic blow to the chin, while wearing an insufficient mouthguard lacking anterior contact, can result in severe distortions to the mandibular bone, and bone fractures. The aim of this study was to clarify how ineffective insufficient occlusal supporting mouthguards are and how dangerous they can be to use. Consequently, in this study, occlusal supportive areas were varied and accelerations of head and distortions of the mandible were measured using an artificial skull model and a pendulum impact device. As a result, the distortions of the mandible tended to increase as the supported area decreased. On the contrary, accelerations of the head decreased as the occlusion part decreased. Thus, a lot of impact energy was consumed in the distortion of the mandible; accordingly, it seemed that only a little destructive energy was transferred to the head. From this study, it would seem that wearing a mouthguard, which is insufficient in the occlusion, has the potential of causing a bone fracture of the mandible. Consequently, mouthguards should have proper occlusion.

The influence of impact object characteristics on impact force and force absorption by mouthguard material

Most impact force and impact energy absorption tests for mouthguards have used a steel ball in a drop-ball or the pendulum device. However, in reality most sports-related trauma is caused by objects other than the steel ball, e.g. various sized balls, hockey puck, or bat or stick. Also, the elasticity, the velocity and the mass of the object could change the degree and the extent of injuries. In this study, we attempted to measure the impact force from actual sports equipment in order to clarify the exact mechanism of dental-related sports injuries and the protective effects of mouthguards. The present study was conducted using the pendulum impact device and load cell. Impact objects were removable. Seven mobile impact objects were selected for testing: a steel ball, baseball, softball, field hockey ball, ice hockey puck, cricket ball, and wooden baseball bat. The mouthguard material used in this study was a 3-mm-thick Drufosoft (Dreve-Dentamid GmbH, Unna, Germany), and test samples were made of the one-layer type. The peak transmitted forces without mouthguard ranged from the smallest (ice hockey stick, 46.9 kgf) to the biggest (steel ball, 481.6 kgf). The peak transmitted forces were smaller when the mouthguard was attached than without it for all impact materials but the effect was significantly influenced by the object type. The steel ball showed the biggest (62.1%) absorption ability while the wooden bat showed the second biggest (38.3%). The other balls or the puck showed from 0.6 to 6.0% absorbency. These results show that it is important to test the effectiveness of mouthguards on specific types of sports equipment. In future, we may select different materials and mouthguard designs suitable for specific sports.

Oro-facial injury and mouthguard usage by athletes in Nigeria

OBJECTIVE

To determine the extent of awareness concerning mouthguard use for sports as well as the amount and type of oro-facial trauma associated with sporting activities among Nigerian athletes.

DESIGN

A questionnaire survey.

MATERIALS AND METHODS

A questionnaire was completed by 273 athletes (91% completion rate) who participated in the National Sports festival in May 2002 in Benin City, Nigeria. The sample was representative of all the 36 states in Nigeria including the Federal capital territory, Abuja. Descriptive statistics were employed and the data were further analysed using the chi-square test.

RESULTS

Awareness concerning mouthguards was claimed by 226 (82.8%) of the athletes but significantly fewer athletes who claimed awareness of the devices were using them. Only 93 (41.2%) of this mouthguard-aware group knew of the three types of mouthguard available. Of all the respondents, 131 (48.0%) believed that wearing mouthguards would reduce the prevalence and/or severity of oro-facial injuries during sports. In all, 158 (57.9%) of them had one form of oro-facial injury or the other with contact sports accounting for most of them (78.5%) while 21.5% resulted from non-contact events. The prevalence of oro-facial injuries was significantly lower while wearing mouth protectors.

CONCLUSIONS

Although the majority of the athletes claimed awareness of mouthguards, less than one-third used them. Over half of the athletes were not sure that mouthguards could reduce the prevalence and/or severity of oro-facial injuries. There is need to educate the athletes more concerning mouthguards.

Knowledge and attitudes of coaches of secondary school athletes in Ibadan, Nigeria regarding oro-facial injuries and mouthguard use by the athletes

- The objective of this study was to assess the perceptions of secondary school sports' coaches about oro-facial injuries and mouth protector usage in sports by the adolescent athletes. A 10-item, self-completion questionnaire was distributed to 42 coaches from 23 secondary schools randomly selected from different parts of Ibadan city in Nigeria between May and June, 2002. The questionnaire sought information on why a mouth protector (mouthguard) is used, when it is required; the types of mouth protector used, the major reasons for choosing a specific mouth protector, and personal feeling as to whether mouthguards prevent oral injury. Descriptive statistics were used for the data while the chi-square statistic was employed to test the significance of association between variables. All the coaches, 25 (59.5%) males and 17 (40.5%) females with age range of 19-51 years and mean age of 38.07 +/- 8.97 years (mean +/- SD), completed and returned the forms (100% completion rate). 95.2% of the coaches believed that mouthguards prevent oral injuries and 95.2% of them also would like more information on different types of mouthguard, while 4.8% each felt otherwise. The main factor determining the choice of the type of mouthguard for athletes by the coaches was the quality of oral protection (57.1%), and the next was the cost (23.8%). Acceptance of mouthguard was scored as positive by 88.1% of the athletes. 81.0% of the coaches felt that mouthguard should be worn at all times (during practices and competitions) while 19.0% would prefer the use during competitions only. The majority of the coaches (71.4%) believed that boxing needs mouthguards, 2.4% each indicated football (soccer) and Judo while 11.9% of the coaches did not indicate any sport. The majority of these Nigerian coaches agreed on the protective effectiveness of mouthguard against sport-related oro-facial injuries, but they are yet to be adequately informed about mouthguards generally so as to correctly advise and influence these adolescent athletes in this regard.

Use of mouthguards by basketball players in Victoria, Australia

Basketball is a popular sport in Australia. Although orofacial injuries are common, mouthguard (MG) wear in basketball appears to be low. The purposes of this study were: to measure mouthguard wear by basketball players before and after a promotional intervention; to assess players' knowledge of the value of mouthguards for prevention of injury; and to describe their experience of orofacial injury. Two questionnaires (baseline and follow-up) were administered to a convenience sample of 496 basketball players in Victoria, Australia. Players recruited were youths (12-15-year olds, n = 208) and adults (18 years and over, n = 288), from all basketball levels (social to elite). Completion of the baseline questionnaire was followed immediately by an intervention comprising written and verbal information, a mouthguard blank and instructions on mouthguard construction. The follow-up questionnaire was mailed to all respondents 10-12 weeks later; 135 youths (65%) and 157 adults (54%) completed this. Mouthguard wear at baseline was low but was more frequent at games (62%) than at training (25%). Despite 90% of players acknowledging the protective value of a mouthguard, wear by youths did not increase following the intervention, and wear by adults increased by only 14% for training and 10% at games. Previous orofacial injury was recorded at baseline by 23% of players, but few had requested compensation from Basketball Australia (youths, 17%; adults, 30%). Two predictor variables were statistically identified as related to mouthguard wear: previous orofacial injury and age group. Mouthguard wear was significantly more frequent amongst players with previous injury; such players were 2.76 times more likely to be wearers than those without previous injury. Youths were 2.31 times more likely to wear mouthguards than adults. Only 34 players (12% of respondents at follow-up) had a mouthguard constructed from the blank provided. Although youth and adult groups differed, the overall extent of mouthguard use was disappointingly low. Despite wide recognition of mouthguard value, the intervention had little effect on promoting their use.

The effect of mouthguard design on stresses in the tooth-bone complex

PURPOSE

Mouthguards protect the tooth-bone complex from impact loads that occur during sporting activity. The aim of this study is to investigate the effects of varying mouthguard thickness and stiffness on the magnitude of tensile stresses in the tooth-bone-complex.

METHODS

A two-dimensional, plane stress, finite element representation of a central maxillary incisor (CMI) is created. For validation purposes, displacements of the incisal edge of the unprotected tooth model are compared with in vivo displacements under similar loads. A protective mouthguard is then superimposed over the model with varied labial thickness (1-6 mm) and stiffness (9-900MPa) representing a range of designs available. A large horizontal static load of 500N is then applied to the anterior surface of the mouthguard and the resulting stresses in the tooth-bone complex are presented. It is suggested that this loading condition most accurately represent the situation occurring when a guarded tooth collides with a soft object (e.g. boxing glove).

RESULTS

It is generally found that mouthguard thickness and stiffness are both desirable in terms of reducing stresses. However, the protection offered by the low-stiffness guards, regardless of thickness, is minimal. Since this low-stiffness (9MPa) is representative of the most common choice of material in mouthguard fabrication, such findings may cast doubt on the ability of popular mouthguards to redistribute stress.

CONCLUSION

While few would disagree that these low-stiffness guards absorb shock during hard-object collisions (e.g. baseballs), they may not protect the tooth-bone during soft-object collisions (e.g. boxing gloves). In order to optimize their protective capabilities for a range of loads, the range of materials used in mouthguard construction may have to be reconsidered.

Laboratory evaluation of mouthguard material

The aim of this study was to evaluate, in vitro, the EVA material (polyvinylacetate-polyethylene copolymer) most commonly used in the fabrication of mouthguards and thus to help understand mouthguard performance and to improve mouthguard design. The material was tested for tensile strength, elongation, hardness and water absorption using specimens and tests described by the American Society for Testing and Materials Standards. Standard EVA sheets of 1, 2, 3 and 5 mm thickness were prepared. With increase in the thickness of the material, both the ultimate tensile strength and the elongation were decreased. The hardness and water absorption were unaffected. It was concluded that. overall, the thicker 5 mm EVA material was recommended for mouthguards as it displayed the least deformation to load and performed equally as well in the tests as other thicknesses.

Fracture resistance of human incisors and premolars: morphological and patho-anatomical factors

305 extracted human front teeth and premolars were investigated for their dynamic resistance to fracture. Morphological factors, such as the anatomical class of tooth and root lengths, and patho-anatomical factors, such as infractions, occlusal and cervical abrasions, composite and amalgam restorations and damage resulting from previous traumatic impacts, were taken into consideration. A comparison of stability after a defined impact stress showed that maxillary canines and premolars had the highest resistance to fracture; this differs significantly from the resistance of maxillary and mandibular incisors. The root length correlates directly with fracture energy and therefore to stability. Composite restorations with an adhesive joint were found to increase the resistance of a tooth to fracture, but amalgam restorations had a weakening effect. Cervical wedge-shaped defects of the tooth cause considerable destabilization, but occlusal abrasion and infractions have only a moderate weakening influence. Previous traumatic stress reduces the resistance to fracture of a tooth by up to 85%. The fracture patterns generated were very similar to clinically observed tooth fractures, indicating the results to be clinically relevant.

Mouthguard use in Australian football

A survey was performed of 961 Australian rules footballers of varying age and football ability in order to determine the prevalence of mouthguard use during training and match play. Emergency dental injury data was obtained to compare the frequency and timing of dental injury in a non-sporting community population. The prevalence of mouthguard use during match play varied between 60% for juniors and 90% for elite footballers whereas the mouthguard use during training ranged between 2% for junior and 40% for elite players. One third of players used over the counter 'boil & bite' mouthguards, generally considered unsatisfactory for dental protection. Of the players who did not currently use mouthguards, most had tried them previously but found them uncomfortable to wear. The community dental injury data showed that the majority of emergency dental injuries were due to sport and followed the temporal pattern of sports participation on week days and weekends. The prevalence of mouthguard use in this population was not known. This study has implications for the provision of emergency dental treatment for sport participants and for improved dental injury prevention measures to avoid expensive and potentially disfiguring dental injuries in young athletes.