Wisdom teeth, or third molars, are the last teeth to erupt, often not appearing until you are 17 or older. Whilst some wisdom teeth cause no problems, they are prone to become impacted or not to erupt properly. Some people’s mouths are not big enough to comfortably contain 32 teeth. Impacted or partially erupted wisdom teeth are difficult to clean, meaning plaque and bacteria can build up, leading to tooth decay and gum disease. Because these teeth develop internally, they can sometimes form painful cysts that can damage surrounding teeth and the jawbone beneath.