PREVENTION OF SPORTS INJURIES AND FABRICATION OF MOUTHGUARD

MDS-Level Comprehensive Answer (Sports Dentistry / Pediatric Dentistry / Oral Medicine)

INTRODUCTION

PART I: PREVENTION OF SPORTS INJURIES

A. Classification of Sports by Risk

B. Types of Sports Injuries - Orofacial

• Enamel fracture (Ellis Class I / Andreasen Type - infraction, enamel fracture)
• Enamel-dentin fracture (Ellis Class II / uncomplicated crown fracture)
• Enamel-dentin-pulp fracture (Ellis Class III / complicated crown fracture)
• Crown-root fractures
• Root fractures
• Tooth luxation injuries: concussion, subluxation, lateral luxation, intrusion, extrusion
• Avulsion (complete displacement from socket)
• Alveolar fractures

• Lacerations of lip, tongue, buccal mucosa
• Contusions
• Frenular tears

• Mandibular fractures (condylar, symphyseal, body)
• Maxillary / middle third fractures (Le Fort types)
• Zygomatic arch fractures

• Sports-related concussion accounts for >15% of the total injury burden in youth sports
• Mouthguards may provide a protective effect against concussion by absorbing forces transmitted to the skull base, though evidence remains inconclusive

C. Preventive Strategies

1. Primary Prevention (Before Injury)

• Mouthguards / Mouth protectors: The most evidence-based primary preventive device. An umbrella review (Agarwal et al., 2025, PMID 40586455) confirmed that mouthguards significantly reduce dentofacial injuries, particularly avulsions and fractures. The risk of orofacial injuries increases by up to 86% for athletes not wearing a mouthguard (EA4SD Position Statement).
• Helmets and face guards: Mandatory in sports like ice hockey, American football, and cricket.
• Face shields: Polycarbonate shields for sports with projectiles (hockey pucks, balls).
• Eye protection: Sports goggles with polycarbonate lenses.
• Rule enforcement: Enforcing rules that prohibit dangerous maneuvers (e.g., high sticking in hockey).
• Pre-participation dental evaluation: Dentist screens for conditions (caries, periapical pathology, orthodontic appliances) that increase injury risk and custom-fabricates appropriate protection.
• Education and awareness: Athletes, coaches, parents, and school staff must be educated about the necessity of protective gear; awareness of mouthguard use remains low in many populations (Shreya et al., 2022).
• Conditioning and training: Neuromuscular training, strength and flexibility programs to reduce predisposing factors.
• Mouthguard regulations by governing bodies: Many national and international sports bodies have mandated mouthguard use (e.g., ADA, FDI World Dental Federation, International Hockey Federation).

2. Secondary Prevention (Early Intervention)

• Sideline emergency kit: Should include saline solution, sterile gauze, tongue blade, small container for tooth storage, contact lens solution or milk (for avulsed tooth transport medium), emergency contact numbers.
• First aid training for coaches: Immediate management of avulsed teeth - rinse with saline, replant if possible, transport in physiologic medium (Hank's Balanced Salt Solution > milk > saliva > saline > dry) within 30-60 minutes.
• Early dental referral: Fractures involving enamel and dentin can be evaluated within 48 hours; pulp involvement requires urgent referral within hours; avulsed teeth require immediate replantation.

3. Tertiary Prevention (Rehabilitation)

• Restorative and endodontic treatment following dental trauma
• Implant rehabilitation for lost teeth in skeletally mature athletes
• Psychosocial rehabilitation
• Updated custom mouthguard post-treatment to prevent re-injury

D. Role of the Sports Dentist in Prevention

• Performs pre-season dental examination
• Identifies at-risk individuals (flared incisors, Class II malocclusion, incompetent lips)
• Fabricates custom mouthguards tailored to the sport
• Educates athletes and coaching staff
• Provides sideline emergency consultation

PART II: MOUTHGUARDS - CLASSIFICATION AND FABRICATION

A. Definition

B. Ideal Requirements of a Mouthguard (ADA/ANSI Standards)

1. Be resilient and capable of withstanding impact forces
2. Cover all the teeth in one arch (maxillary arch preferred - upper arch protection also protects lower teeth and jaw by cushioning)
3. Provide adequate thickness - minimum 3-4 mm at the labial surface of anterior teeth, 1.5-2 mm over incisal edges (EA4SD 2025 guidelines)
4. Extend to at least the distal surface of the first maxillary molar
5. Not interfere with breathing or speech
6. Be resistant to deformation (tear-resistant)
7. Be comfortable and retentive
8. Be odorless and tasteless
9. Be easily cleaned and maintained
10. Be affordable
11. Be fabricated from FDA/CE-approved materials

C. Classification of Mouthguards

Type I - Stock (Ready-made / Pre-formed)

• Available off-the-shelf in sporting goods stores
• Come in limited sizes (S, M, L)
• Provide least protection and adaptation
• Must be held in position by jaw closure - interfere significantly with breathing and speech
• Not recommended by the ADA or ADA-accredited sports bodies
• Use: When no other option is available; recreational, non-contact sports

Type II - Mouth-formed (Boil and Bite)

• Commercially available thermoplastic shells
• Require modification by immersion in hot water
• Fabrication steps:
  1. Choose appropriate size and desired color from commercially available options
  2. Immerse in boiling water for 10-45 seconds (per manufacturer's instructions) until softened
  3. Cool briefly in cold water to reduce temperature to a safe level
  4. Transfer immediately to athlete's mouth; position over maxillary teeth
  5. Apply finger pressure from the dentist/operator, then instruct patient to bite down firmly
  6. Patient uses lips, tongue, and cheeks to adapt the guard to the dental arch
  7. Remove and cool in cold water to set the shape
  8. Trim excess material with scissors if needed
  9. Check for retention, coverage, and comfort
• Better than stock guards but inferior to custom-made
• Acceptable for some contact sports as a temporary or training solution

Type III - Custom-made (Individually Fabricated)

D. Materials Used

• Ethylene Vinyl Acetate (EVA) - most commonly used; excellent shock absorption, flexible, odorless, tasteless; comes in sheets of varying thickness (2 mm, 3 mm, 4 mm, 5 mm)
• Polyvinyl acetate-polyethylene (pEVA)
• Cyclic Olefin Copolymer (COC)
• Soft acrylic resin
• Silicone elastomers - good elasticity but poor tear resistance
• Laminated multi-layer combinations - one soft/elastic inner layer for shock absorption + one rigid outer layer for force distribution; recommended by EA4SD 2025

E. Detailed Fabrication of Type III (Custom-made) Mouthguard

Step 1: Pre-operative Assessment

• Medical and dental history review
• Intraoral examination: assess dental arch, occlusion, presence of orthodontic appliances, missing teeth, implants, periodontal status
• Identify type of sport and level of contact risk
• Record jaw relationship

Step 2: Impression Taking

• Material: Alginate (irreversible hydrocolloid) or polyvinyl siloxane (for greater dimensional accuracy)
• Technique: Upper (maxillary) arch impression is mandatory. A lower arch impression is required if a bimaxillary mouthguard is planned.
• For patients with fixed orthodontic appliances: Apply a thin rope of utility wax over bonded brackets before impression to prevent alginate tearing on removal (Croll et al., AAPD 2004)

Step 3: Fabrication of Study Casts

• Pour impressions in Type II dental stone or plaster within 1 hour of impression taking
• Trim the cast to proper occlusal plane
• The cast serves as the working model for mouthguard adaptation

Step 4: Interocclusal Record (if bimaxillary mouthguard)

• Wax bite registration at centric occlusion or slightly open vertical dimension
• Necessary to establish the thickness of the interocclusal component

Step 5A: Vacuum-forming Process

• Vacuum-forming machine (e.g., Erkoform, Drufomat)
• EVA thermoplastic sheet (3-4 mm thickness for standard; 4-5 mm for high-impact)
• Maxillary stone cast
• Scissors or heat knife for trimming
• Pumice and rag wheel for finishing

1. Mount the maxillary stone cast on the vacuum-forming machine platform
2. Place the EVA sheet in the heating frame of the machine
3. Activate the heating element; heat the sheet until it sags approximately 1 inch (2-2.5 cm) - signaling uniform softening
4. Quickly lower the heated EVA sheet over the cast
5. Simultaneously activate the vacuum pump (negative pressure: ~1 bar / ~15 psi)
6. The vacuum draws the softened EVA tightly and uniformly over all surfaces of the cast
7. Hold vacuum for 30-60 seconds until the material cools and sets
8. Release vacuum, remove the formed guard from the cast

• Retention and stability (should not dislodge during speaking)
• Full coverage of all teeth to first molar
• Comfort and absence of tissue impingement
• Absence of speech interference
• Check occlusion: even contact posteriorly; anterior teeth slightly discluded

Step 5B: Pressure-laminated Process (for high-impact sports)

• Pressure-forming machine (e.g., Biostar, Erkopress-2004, Drufomat)
• Multiple EVA sheets of different densities (e.g., soft inner layer 2 mm + firm outer layer 2 mm = 4 mm total)
• Working cast

1. Heat the first (soft/inner) EVA sheet and pressure-form it over the cast (pressure: 4-6 bar)
2. Allow to cool and cool under running water
3. Do NOT remove from cast
4. Apply second (firmer/outer) EVA sheet over the first layer while still on cast
5. Heat and pressure-form the second sheet over the first, bonding the layers
6. Optionally, embed team colors, logos, or radiopaque markers between layers
7. Trim, finish, and polish as with vacuum-formed technique
8. Each additional layer increases protective capacity for high-impact sports

• Superior shock absorption
• Multi-layer design allows customization of rigidity
• More durable, longer service life
• Can accommodate protective padding over vulnerable areas (e.g., post-trauma sites)

F. Bimaxillary (Double) Mouthguard Fabrication

1. Impressions of both arches
2. Fabrication of both casts
3. Jaw relationship record (in centric occlusion or desired open position)
4. Mount casts on articulator
5. Fabricate wax model of the mouthguard establishing interocclusal space
6. Flasking and investing the wax model
7. Wax elimination (dewaxing by boiling)
8. Pack with silicone or heat-cured acrylic resin or EVA
9. Polymerization/curing under heat and pressure
10. Deflask, finish, polish, try in

G. Mouthguard for Special Populations

H. Maintenance and Care of Mouthguards

• Rinse with cool water or mouthwash before and after use (hot water causes deformation)
• Clean with a toothbrush and mild soap
• Store in a vented container to allow drying
• Inspect regularly for tears, perforations, and distortion
• Replace when worn, distorted, or when dentition changes significantly
• Children in primary/mixed dentition: replace every 6-12 months
• Adults with stable dentition: replace every 1-2 seasons

PART III: COMPARISON OF MOUTHGUARD TYPES

PART IV: RECENT EVIDENCE

• Custom-made mouthguards offer superior protection and comfort compared to prefabricated types
• MGs significantly reduced avulsions and crown fractures in athletes
• Mixed evidence exists regarding MG effect on concussion prevention
• The authors recommend mandatory mouthguard use policies and enhanced athlete education
• Risk of orofacial injury is increased by up to 86% without a mouthguard

SUMMARY

• Agarwal A et al. Impact of mouthguards on the prevention of dentofacial injuries - umbrella review. J Indian Soc Pedod Prev Dent. 2025. PMID 40586455
• Shreya S et al. Sports-related facial trauma in Indian population - systematic review. J Indian Soc Pedod Prev Dent. 2022. PMID 35439876
• EA4SD Position Statement - Custom-made Sport Mouthguards. PMC12056218. 2025.
• Textbook of Family Medicine 9e - Dental Trauma section
• Ranalli DN. Sports dentistry and dental traumatology. Dent Traumatol. 2002; 18:231-236.
• American Dental Association. Using mouthguards to reduce sports-related oral injuries. J Am Dent Assoc. 2006; 137:1712-1720.