Gingiva in the context of "Mouth guards"

A tooth (pl.: 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, tearing food, for defensive purposes, to intimidate other animals often including their own, or to carry prey or their young. The roots of teeth are covered by gums. Teeth are not made of bone, but rather of multiple tissues of varying density and hardness that originate from the outermost embryonic germ layer, the ectoderm.

The general structure of teeth is similar across the vertebrates, although there is considerable variation in their form and position. The teeth of mammals have deep roots, and this pattern is also found in some fish, and in crocodilians. In most teleost fish, however, the teeth are attached to the outer surface of the bone, while in lizards they are attached to the inner surface of the jaw by one side. In cartilaginous fish, such as sharks, the teeth are attached by tough ligaments to the hoops of cartilage that form the jaw.

In dentistry, dental calculus or tartar is a form of hardened dental plaque. It is caused by precipitation of minerals from saliva and gingival crevicular fluid (GCF) in plaque on the teeth. This process of precipitation kills the bacterial cells within dental plaque, but the rough and hardened surface that is formed provides an ideal surface for further plaque formation. This leads to calculus buildup, which compromises the health of the gingiva (gums). Calculus can form both along the gumline, where it is referred to as supragingival ('above the gum'), and within the narrow sulcus that exists between the teeth and the gingiva, where it is referred to as subgingival ('below the gum').

Calculus formation is associated with a number of clinical manifestations, including bad breath, receding gums and chronically inflamed gingiva. Brushing and flossing can remove plaque from which calculus forms; however, once formed, calculus is too hard (firmly attached) to be removed with a toothbrush. Calculus buildup can be removed with ultrasonic tools or dental hand instruments (such as a periodontal scaler).

In dentistry, the crown is the visible part of the tooth above the gingival margin and is an essential component of dental anatomy. Covered by enamel, the crown plays a crucial role in cutting, tearing, and grinding food. Its shape and structure vary depending on the type and function of the tooth (incisors, canines, premolars, or molars), and differ between primary dentition and permanent dentition. The crown also contributes to facial aesthetics, speech, and oral health.

Periodontal disease, also known as gum disease, is a set of inflammatory conditions affecting the tissues surrounding the teeth. In its early stage, called gingivitis, the gums become swollen and red and may bleed. It is considered the main cause of tooth loss for adults worldwide. In its more serious form, called periodontitis, the gums can pull away from the tooth, bone can be lost, and the teeth may loosen or fall out. Halitosis (bad breath) may also occur.

Periodontal disease typically arises from the development of plaque biofilm, which harbors harmful bacteria such as Porphyromonas gingivalis and Treponema denticola. These bacteria infect the gum tissue surrounding the teeth, leading to inflammation and, if left untreated, progressive damage to the teeth and gum tissue. Recent meta-analysis have shown that the composition of the oral microbiota and its response to periodontal disease differ between men and women. These differences are particularly notable in the advanced stages of periodontitis, suggesting that sex-specific factors may influence susceptibility and progression. Factors that increase the risk of disease include smoking, diabetes, HIV/AIDS, family history, high levels of homocysteine in the blood and certain medications. Diagnosis is by inspecting the gum tissue around the teeth both visually and with a probe and X-rays looking for bone loss around the teeth.

Natal teeth are teeth that are present above the gumline (have already erupted) at birth, and neonatal teeth are teeth that emerge through the gingiva during the first month of life (the neonatal period).

The incidence of neonatal teeth varies considerably, between 1:700 and 1:30,000 depending on the type of study; the highest prevalence is found in the only study that relies on personal examination of patients.

A dental consonant is a consonant articulated with the tongue against the upper teeth, such as /θ/, /ð/. In some languages, dentals are distinguished from other groups, such as alveolar consonants, in which the tongue contacts the gum ridge. Dental consonants share acoustic similarity and in the Latin script are generally written with consistent symbols (e.g. t, d, n).

In the International Phonetic Alphabet, the diacritic for dental consonant is U+032A ◌̪ COMBINING BRIDGE BELOW. When there is no room under the letter, it may be placed above, using the character U+0346 ◌͆ COMBINING BRIDGE ABOVE, such as in /p͆/. However, this has a different meaning in the Extensions to the IPA.