As long as you do not have any signs or symptoms related to your wisdom teeth, you do not need to have them extracted. However, you need to have regular exams with a dentist to ensure the wisdom teeth are not causing any problems.
1. It is usually diffcult to keep clean wisdom teeth, do to their position, being the most posterior teeth in the oral cavity, and prone to cavites, gingivits and periodontal disease.
2. If they are impacted means they are not grown in the oral cavity and deep in the bone, they might form cyst around the tooth and cyst might expand and cause the need for extensive procedure like jaw resection.
3. Wisdom teeth might cause pain and infection on the adjusant teeth by putting pressure and causing resorption.
However; there is times elected to leave the wisdom teeth in the arch. If the patient has excellent hygiene, and no cavites detected upon a total examination, the teeth are aligned well and wisdom teeth proximity to the vital anotmoy such as sinus and nerve are very close, it will be better to leave the wisdom teeth to prevent damage to the sinus or nerve.