A mouth mirror or dentist's mirror is an instrument used in

dentistry Dentistry, also known as dental medicine and oral medicine, is the branch of medicine focused on the teeth, gums, and mouth. It consists of the study, diagnosis, prevention, management, and treatment of diseases, disorders, and conditions of ...

. The head of the

mirror A mirror or looking glass is an object that reflects an image. Light that bounces off a mirror will show an image of whatever is in front of it, when focused through the lens of the eye or a camera. Mirrors reverse the direction of the im ...

is usually round, and the most common sizes used are No. 4 (⌀ 18 mm) and No. 5 (⌀ 20 mm). A No. 2 is sometimes used when a smaller mirror is needed, such as when working on back teeth with a

dental dam A dental dam or rubber dam is a thin, square sheet, usually latex or nitrile, used in dentistry to isolate the operative site (one or more teeth) from the rest of the mouth. Sometimes termed "Kofferdam" (from German), it was designed in the Un ...

in place. The mouth mirror has a wide range of uses. Three of its most important functions are allowing indirect vision by the

dentist A dentist, also known as a dental surgeon, is a health care professional who specializes in dentistry (the diagnosis, prevention, management, and treatment of diseases and conditions of the oral cavity and other aspects of the craniofacial c ...

, reflecting light onto desired surfaces, and retraction of

soft tissue Soft tissue is all the tissue in the body that is not hardened by the processes of ossification or calcification such as bones and teeth. Soft tissue connects, surrounds or supports internal organs and bones, and includes muscle, tendons, ...

s. There exist 2 different norms of the thread that are not compatible with each other. The US norm has a taper thread and is mostly used in the United States, Canada, Spain, and South Korea.Mouth mirror thread normation
Source (German): Daniela Tocan (CC-BY-SA) Indirect vision is needed in certain locations of the

mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on ...

where visibility is difficult or impossible. The posterior (or lingual) surfaces of the anterior

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, ...

is a notable area where mouth mirrors are often used. Other areas of the mouth can be viewed more readily with the mouth mirror, even though it would be possible to see them if the dentist or

dental hygienist A dental hygienist or oral hygienist is a licensed dental professional, registered with a dental association or regulatory body within their country of practice. Prior to completing clinical and written board examinations, registered dental hygien ...

adjusted their body into a poor position. Without the mouth mirror, poor body positioning would occur daily and lead to chronic postural problems, especially in the back and

neck The neck is the part of the body on many vertebrates that connects the head with the torso. The neck supports the weight of the head and protects the nerves that carry sensory and motor information from the brain down to the rest of the body. In ...

. There are other areas of the mouth where lighting is difficult, even with overhead dentists' lights. In these instances, the mouth mirror is used to reflect light onto those surfaces. This is especially useful if the mirror is simultaneously being used for the indirect vision of an obscure area. Additionally, the mouth mirror is used to retract tissues, such as the

tongue The tongue is a muscular organ in the mouth of a typical tetrapod. It manipulates food for mastication and swallowing as part of the digestive process, and is the primary organ of taste. The tongue's upper surface (dorsum) is covered by taste ...

cheek The cheeks ( la, buccae) constitute the area of the face below the eyes and between the nose and the left or right ear. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve. The area between the insi ...

s, to gain better visualization of the teeth. Dentist's mirrors are also commonly used by

engineer Engineers, as practitioners of engineering, are professionals who Invention, invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considerin ...

s to allow vision in tight spaces and around corners in equipment. They are a common tool in

optics Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultrav ...

and

laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The ...

labs as well.

References

*Summit, James B., J. William Robbins, and Richard S. Schwartz. "Fundamentals of Operative Dentistry: A Contemporary Approach." 2nd edition. Carol Stream, Illinois, Quintessence Publishing Co, Inc, 2001. {{ISBN, 0-86715-382-2. Dental equipment Mirrors