mouth guard

noun

variants or mouthguard

ˈmau̇th-ˌgärd 

plural mouth guards or mouthguards

1

sports : a protective typically plastic device placed inside the mouth that covers the teeth and gums and often the lips and is worn especially during a contact sport (such as football, hockey, or boxing) to prevent injuries to the mouth or teeth

Clamping down on his blue mouth guard, he patrolled the area in front of the Virginia goal with the swagger and menace of a middle linebacker.

—John Walters

Although the NBA does not mandate mouthguards, many stars, including [Stephen] Curry, wear them voluntarily to prevent dental injuries.

—Aidin Vaziri

2

a

: a removable dental appliance that covers the upper or lower teeth and is worn typically at night to minimize the negative effects of various oral issues (such as bruxism)

… mouth guards are not designed to prevent clenching or grinding, but they do redistribute the forces exerted while grinding and thus help protect teeth.

—UC Berkeley Wellness Letter

called also night guard

b

: a similar device that prevents airway obstruction to treat snoring or sleep apnea

You may be a candidate for an oral appliance, fitted by a dentist experienced in treating sleep apnea. It's a mouthguard that repositions the lower jaw, tongue and uvula …

—The Toronto Star

Word History

First Known Use

1936, in the meaning defined at sense 1

Rhymes for mouth guard

• asgard
• backyard
• barnyard
• blackguard
• bombard
• brickyard
• canard
• churchyard
• coastguard
• courtyard
• debarred
• diehard

Medical Definition

mouth guard

noun

variants or mouthguard

ˈmau̇th-ˌgärd 

1

: a protective typically plastic device placed inside the mouth that covers the teeth and gums and often the lips and is worn especially during a contact sport (such as football, hockey, or boxing) to prevent injuries to the mouth or teeth

The preponderance of evidence appears to indicate that helmets and mouth guards provide a significant benefit in protecting against many catastrophic head, neck, and orofacial injuries.

—Daniel H. Daneshvar et al., Clinics in Sports Medicine

2

a

: a removable dental appliance that covers the upper or lower teeth and is worn typically at night to minimize the negative effects of various oral issues (such as bruxism)

… mouth guards were prescribed to reduce bruxism activity and temporomandibular joint symptoms, promoting relaxation of facial muscles and protecting the natural dentition against further wear.

—Franciele Floriani et al., Case Reports in Dentistry

called also night guard

b

: a similar device that prevents airway obstruction to treat snoring or sleep apnea

Patients are asked whether they have been diagnosed with OSA [=obstructive sleep apnea], and if so, whether they own equipment, such as a CPAP machine or a mouth guard, and whether they use the equipment.

—Betsy Szeto et al., Anesthesia & Analgesia