
1) American football equipment 2) Defender of a river area 3) Dental equipment 4) Protector in the ring 5) Rugby league equipment
Found on
https://www.crosswordclues.com/clue/mouthguard

A mouthguard is a protective device for the mouth that covers the teeth and gums to prevent and reduce injury to the teeth, arches, lips and gums. A mouthguard is most often used to prevent injury in contact sports, as a treatment for bruxism or TMD, or as part of certain dental procedures, such as tooth bleaching. Depending on application, it may...
Found on
http://en.wikipedia.org/wiki/Mouthguard

Individually molded device designed primarily to be worn for the purpose of helping prevent injury to the teeth and their surrounding tissues. Sometimes called a mouth protector.
Found on
http://www.ada.org/glossaryforprofessionals.aspx

a soft-fitted device which protects teeth against impact or injury.
Found on
http://www.cosmeticdentistryguide.co.uk/glossary.html

<dentistry> A pliable plastic device adapted to cover the maxillary teeth that is used to protect the mouth from injury when participating in contact sports. ... The use of a mouthguard is especially important for orthodontic patients, to prevent injuries. ... (08 Mar 2000) ...
Found on
http://www.encyclo.co.uk/local/20973

A removable device used to protect the teeth and mouth from injury caused by sporting activities. The use of a mouthguard is especially important for orthodontic patients.
Found on
http://www.encyclo.co.uk/local/22244

A device to be worn in the mouth and prevents injury on teeth and/or jaw during teeth grinding or sport events.
Found on
http://www.jeffersondentalclinics.com/services/dental-terms.html

Device that fits over the teeth to prevent injury to the teeth, mouth or lips. May also refer to a device that prevents tooth grinding or treats temporomandibular disorders.
Found on
https://www.encyclo.co.uk/local/21141
No exact match found.