Developmental variations of the teeth.
Each tooth has three parts:- the crown, the root, and the pulp cavity. The crown is the exposed area of the tooth, which is outside the gum. It is covered with a hard substance called enamel. The ivory-coloured internal part of the crown below the enamel is the dentin. The root of a tooth is embedded in the jaw and covered by a bony tissue called cementum. The pulp cavity in the centre of the tooth contains the blood vessels and nerves.
Teeth usually appear 5 to 8 months after birth. Baby-bottle syndrome may result in decay of all of the upper teeth and the lower posterior teeth. This syndrome occurs when an infant is put to bed with a bottle of sugar water, milk or fruit juice. The carbohydrates in the solutions cause demineralisation of the tooth enamel, which leads to tooth decay.
By the time children are 2 years old, they usually have all 20 of their temporary teeth. At about age 6 or 7, children start losing their deciduous teeth, and these are gradually replaced by the 33 permanent teeth.
The incidence of periodontal disease increases during pregnancy because the rise in female hormones affects gingival tissues and increases its reaction to bacterial plaque. Many pregnant women experience more bleeding from the gingival sulcus during brushing and increased redness and the swelling of the gingiva (the gum).
Teeth turn yellowish in colour as a part of the aging process. Teeth are normally off-white. With age, the enamel thins and the yellow-gray colour of the inner portion of the teeth begins to show. In addition, coffee drinking and cigarette smoking can stain the teeth. Commercial teeth whitening products and whitening treatments offered at dental offices are available to consumers who desire whither teeth for cosmetic reasons.
Lack of fluoridated water and preventive dentistry during their developmental years caused tooth and gum problems in older adults. As a result, some elders may have few permanent teeth left, and some have dentures. Loss of teeth occurs mainly because of periodontal disease (gum disease) rather than dental caries (cavities),: however, caries are also common in middle-aged adults.
Some receding of the gums and a brownish pigmentation of the gums occur with age. Because saliva production decreases with age, dryness of the oral mucosa is a common finding in older people.
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admin on March 2nd 2009 in Dentistry and dental treatment