• Buildup of dental plaque (a deposit of food particles, mucus, and bacteria) on the surface of the teeth is the common cause of discoloration.

• Plaque-stained teeth are often yellowish brown, but children's teeth may be black or green.

• Teeth can get stained due to drinking of tea, coffee, chewing or smoking tobacco and also due to some liquid medicines that contain iron.

• The discolouration can also be caused if children are given certain drugs while their secondary teeth are developing. 

• For example, if tetracycline is given to babies or children under age 10, it may cause a yellow discoloration of the secondary teeth. 

• If the drug is given to a pregnant woman, the baby born may have discoloured primary teeth.

• Fluorosis is the case in which the teeth develops a mottled colour due to an excess of natural fluoride in the water in some parts of the world. 

• However, where fluoride is added to the water to reduce tooth decay, the concentration is too high a dose of fluorosis. 

• Fluorosis may also develop if children are given very high dose of fluoride drops or pills.

• When the soft center, or the pulp, of the tooth dies, tooth may become darker than normal following irreversible pulpitis.  

• Root canal treatment (opposite page) may cause a tooth to darken if the material used to fill the tooth is dark in color.
   

• Staining on the surface of the teeth should be routinely removed by scaling and polishing of teeth by your dentist or oral hygienist. 

• Teeth can be bleached if the staining is severe. 

• If a single tooth is discolored as a result of a condition such as pulpitis or following root canal treatment, a porcelain or plastic veneer may be bonded to the front of the tooth, or the top of the tooth can be replaced by a crown 

• Discolouration of teeth can be prevented by brushing and flossing the teeth and gums regularly.

• Teeth usually become impacted when there is not enough room in the mouth for them to grow into their correct positions. 

• Impacted teeth may remain entirely buried in the jawbone, with few or no symptoms, or only partly erupt through the gum. 

• If a tooth starts to grow in the wrong direction and pushes against other teeth or the jawbone impaction can be occurred.

• Wisdom teeth are most likely to become impacted, followed by the upper canines. These teeth emerge at a later stage of life than other teeth, and frequently there is insufficient room in the mouth for them to erupt normally.

• Impacted teeth commonly occur in adolescents and young adults when the teeth are still emerging.

• Pain and inflammation may be caused due to impacted teeth. 

A partly erupted tooth may be covered by a flap of gum under which plaque (a deposit including food particles, mucus, and bacteria) accumulates, leading to inflammation of the gum and gradual decay of the tooth.