Adults usually have 32 teeth. Wisdom teeth are the last molar on both sides of the upper and lower jaws. They are the last type of teeth to appear, usually in your late teens or early twenties. However, usually our jaws are not able to fit all 32 teeth; at most 28. If there is enough room, the wisdom tooth will grow normally in place.
If there is a lack of space to accommodate the wisdom teeth when the finally appear, it will get stuck with the tooth in front of it. This causes the wisdom teeth to grow at an angle, which is also known as “impacted”.
If your area around your wisdom teeth starts to ache or hurt, it is best to schedule an appointment with your dentist. An x-ray of the mouth will be conducted to give a clearer image of your teeth if your tooth needs to be removed.
Food and bacteria can get stuck around the edges of your impacted tooth, forming plaque. The buildup of plaque can lead to several dental-related diseases.
Tooth decay may occur when plaque starts to eat away the tooth. Advanced stages of tooth decay can even leave cavities in the tooth, affecting its surroundings.
Gingivitis, also called gum disease, occurs when toxins generated by the plaque starts to irritate the gums, making them red and swollen. Gingivitis can also affect the surrounding teeth and bone around the affected tooth. If the soft tissue is affected, this infection is called pericoronitis. A bacterial infection known as cellulitis may occur, affecting the throat, tongue or cheek.
Sometimes, accesses form when pus starts to collect in the wisdom tooth. A cyst might also develop when the wisdom tooth has yet to break through the gum.
Though this can be usually be remedied with a thorough rinse of antiseptic mouthwash and taking antibiotics, sometimes this is insufficient. When this happens, the removal of wisdom tooth is recommended.
Source(s):
https://www.dentalhealth.org/tell-me-about/topic/sundry/wisdom-teeth
http://www.nhs.uk/conditions/wisdom-tooth-removal/pages/introduction.aspx