Mouthguard in Sports: A Review

Headnote

Abstract

Background: Sports starts at an early age and hence children and young adults are most susceptible to sports-related oral injury. A unique dental and maxillary morphology behavioural risk factors, such as hyperactivity and an increase in risk-taking behavbur of a child could be the reasons for increase in the incidence of trauma in children during sports. The use of mouth guards in contact sports effectively prevents oral injury and preserves oral structures.

Aim: The aim of this article is to review the types and properties of mouthguards, current fabrication methods and the role of mouthguardsinpreventionoforofacialinjuriesinyoungdentitionandalsotoprovideanoverviewtodentists.

Conclusion: "Prevention is better than cure". Mouthguards play an important role in the prevention of injuries. Hence, use of mouthguards should be continued in sports activities where there is significant risk of orofacial injury.

Keywords: Mouthguard, gum shields, mouth protector, sports, dental trauma.

Introduction

Globally, sports are becoming more attractive to adolescents and young adults. In all sporting activities, accidents and traumatic oral injuries are common. Sporting activities contribute to nearly one-thirdof all dental injuries. 12Unlike some other injuries, a single traumatic injury to the dentition may never heal completely, and it can create a lifetime ofexpensivclongtermproblems.Mouthguardsofferprot-ection by separating the cheeks and lips from the teeth, making users less susceptible to soft-tissue laceration and preventing opposing arches from traumatic contact.36 Before the second world war, Jack Dempsey and Gene Tunney were probably the last of the heavyweight champions to fight without amouthpiece.7

Mouthguards or "gum shields" or "mouth protector" were originally developed in 1890 by a London dentist, Woolf Krause. Lip injuries were a common and often disabling accompaniment of boxing contests in that era. Philip Krause, his son, who was also an amateur boxer, subsequently refined the design of the gum shield and made them from vella rubber. In 1916, a Chicago dentist, Thomas Carlos, probably manufactured the first mouth-guard in United States.8 Bythe 1930s, mouthguards were part of the standard boxers' equipment and have remained so since that time. These gum shields were originally made from guttaperchaandwereheldinplacebyclenchingtheteeth.7 This article reviews the available literature on the types and properties of various available athletic mouthguards, their fabrication methods and their role in reducing the incidence of sports oral injury.

Incidence

The ADA estimated that one-half of the injuries sustained by high-school football players occurred in or around the mouth, and that most of those injuries could have been prevented by the use of orofacial protectors during play.

Oral injury vary widely based on the sport played, level of competition, the participant's age and sex, and other factors.10'" Dental and soft-tissue injuries typically are associated with collision and contact sports such as football or ice hockey. Oral trauma is just as common, in basketball, soccer, baseball, bicycling, in-line skating, gymnastics and other sports.12 Yet, in limited-contact sports such as basketball that do not necessarily require mouthguards or other orofacial protectors, reported 14 to 34% of injuries to the orofacial area.1317

Sports-related oral injury in school children are mainly seen between the ages of 7 and 11 years.1819 Children are particularly at risk because of their dental and maxillary morphology, behavioural risk factors, such as hyperactivity and an increased risk-taking behaviour.2021 With hundreds of oral injuries occurring in youth baseball each year, and even more injuries to basketball players involving the teeth or oral cavity, mouthguards can offer significant protection to athletes participating in these and other non-contact sports.2022 Approximately 80% of traumatic dental injuries occur to the maxillary incisors.811 While male athletes generally are more susceptible.23

Mouthguard

In designing mouthguard, the nature of the collision like hard or soft objects and characteristics of the mouth (e.g., brittle incisors more rugged occlusal surfaces of molars, soft gingiva) should also be considered. The American Society for Testing and Materials gave three categories for athletic mouthguards:24

- Ready-made or stock mouthguard

- Mouth-formed, or "boil-and-bite" protector

- Custom-made model, either vacuum-formed or pressure-laminatedby a dentistor a dental laboratory

The "stock mouthguards", are preformed thermoplastic tray that fits loosely over the teeth These are inexpensive, ready-for-wearmodelwith littleto no retentionor adaptability to hard and soft tissues. To be held in place, the wearer'smouthneeds to beclosed to provideany protective benefit; this can interfere with breathing and speaking. For these reasons, many consider the stock mouthguard to be less protective.25

The "mouth formed" or "boil and bite guards", are available in two varieties: the shell-liner mouthguard and the thermoplastic, boil-and-bite model. The shell-liner mouthguard consists of a polyvinyl chloride outer shell that fits loosely over the dentition and an inner lining of plasticized acrylic gel or silicone rubber.2628 The boil-and-bite mouthguard is manufactured typically as a standard tray of thermoplastic material (such as ethylene vinyl acetate- EVA). A boil-and-bite mouthguard can be formed by first softening it in hot water, followed by brief cooling in cold water, placing it in the mouth and then shaping the material with fingers tongue and some biting pressure to form a stable impression.2930

The "custom made" available in several types, is individually designed and form-fitted in a dental office or made in a professional laboratory. Although custom mouthguards can be the most expensive option, they are preferred as provide better retention and comfort, less interference with speech and breathing, and more adaptability to orthodontic appliances.510

The simplest of these is a vacuum formed guard made from a single layer of polyvinyl acetate-polyethylene. More complex designs incorporate sandwiching of multiple layers or laminations of the material, under high pressure andhigh temperature to form the final unit. This technique allows sport specific designs such as incorporating hard inserts over the incisors for ball or missile sports or the use of more shock absorbing material for collision sports. For enhanced reduction and absorption of transmitted forces during impact, a material thickness of 4 to 5mm is best suited.3133

Materials used for mouthguards include: (i) polyvinyl-acetate-polyethylene or ethylene vinyl acetate (EVA) copolymer; (ii) polyvinylchloride; (iii) latex rubber; (iv) acrylic resin; and (v) polyurethane. Latex rubber, a popular material used in early mouthguards is not in use now a days, because it has lower shock absorbency, lower hardness and less tear and tensile strength than EVA or polyurethane.

To provide adequate protection, the mouthguard should

- be properly fitted and accurately adapted to the wearer's mouth and to his or her oral structures;

- be made of resilient material approved by the U.S. Food and Drug Administration and cover all remaining teeth on one arch, customarily the maxillary;

- stay in place comfortably and securely;

- be phySologically compatible with the wearer;

- be relatively easy to clean;

- have high-impact energy absorption and reduce transmitted forces upon impact.28

Mouthguards typically are designed to fit over occlusal surfaces of the maxillary teeth and gingivae.34 Class III occlusions may require mouthguard placement on the mandibular arch.27 Formation of a professionally fitted custom mouthguard consists of five standard steps as follows:

- making an impression of the patient's arch for which the mouthguard will be made (an impression of the opposing arch and a bite registration are taken only if occlusal adjustments are to be made with an articulated cast);

- pouring a high-strength stone model of the patient's upper teeth;

- forming one or more sheets of thermoplastic material (such as ethylene vinyl acetate, polyvinyl chloride, polyvinyl acetate, natural rubber, soft acrylic resin or othermaterial)onthestonemodel;

- seating the mouthguard with proper occlusal balance and equilibration;

- final trimming of excess material from the mouthguard.

Although many authors claim that mouthguards offer an effective means of preventing concussion and spinal injuries, the evidence for this statement is limited. Stenger et al., claimed benefit for both head and cervical spinal injuries by mouthguard use.35 It had abolished the symp-toms of Meniere's disease, cervical nerve root compress-ion, chronic "burners" (cervical radicular syndrome), dizzy spells/low back pain and repeated concussion. Hickey et al., showed that a mouthguard could attenuate the forces appliedtotheheadastheresultofablowonthepointofthe chin.36 However, it is unlikely that a mouth-guard would offereffectiveprotectionagainstbrainorspinalcord injury and this accords with the known pathophysiology of such injuries.37

The risk of an orofacial sports injury increased by 1.6-1.9 times 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.7

Conclusion

Mouthguards should be used in sport activities to prevent the risk of various orofacial injury. It is hence recommended by the Council on Scientific Affairs and the Council on Access, Prevention and Inter professional Relations that athletically active people of all ages should use a properly fitted mouthguard in any sporting or recreational activity that may pose a risk of injury. It is generally recommended that:26

1. Mouthguards be worn during both practice sessions and games.

2. The habit of wearing a mouthguard should begin at an early age.

3. Mouthguards be regularly replaced while children are still growing.

4. Adult players replace their mouthguards at least every two years.

Prevention is better than cure, as traumatic injury to the dentition may never heal completely, and it can create a lifetime of expensive, long term problems for the affected sports person.

References

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Disclosure : The authors report no conflicts of interest