Wisdom teeth are normally the last teeth to appear in the mouth. It usually happens when people are older and wiser. That is, when they are in their late teenage years or early twenties.

Wisdom teeth are molars, or chewing teeth at the back of the mouth. The third set of molars, if you have them, are your wisdom teeth.

They can grow into place normally and never cause a problem. But often there is not enough room for them in the mouth. They might crowd the other teeth. Sometimes they even push through the gums sideways.

An impacted wisdom tooth is one that fails to completely rise through the gums -- the term is erupt. Wisdom teeth that only partly erupt can leave space for bacteria to enter around the tooth. Infection is a risk in these cases.

Experts say people should have their mouths examined between the ages of sixteen and twenty for placement of their wisdom teeth. X-rays can show wisdom teeth below the gums. Those that are not well aligned and become impacted are often removed.

The American Dental Association says removal is generally advised when wisdom teeth only partly break through the gums. Removal is also advised if there is a chance that poorly aligned wisdom teeth will damage other teeth. And removal is called for in cases where fluid collects around a wisdom tooth that is partly or fully below the gum.

But why do we have wisdom teeth if we often need to get them removed? One theory has to do with our diets. Scientists say the diet of prehistoric humans probably required more chewing teeth. Life was probably a little rougher on the teeth back then, too. So it was good to have extras.

The removal of wisdom teeth is performed by oral surgeons. They say if removal is advised, the best time to do it is before the teeth cause any problems or pain.

The American Association of Oral and Maxillofacial Surgeons says young adults are the best candidates for wisdom teeth removal. The group says older patients may be at greater risk for disease in the tissue surrounding the molars.

Patients can have general anesthesia during the operation. Or they might choose to have a local painkiller and remain awake. It may depend on the condition of the wisdom teeth and the number to be removed.

After surgery, there can be swelling of the gums and face and some pain. Both can be treated with cold wraps and medication.

智齿通常是最后长出的牙齿。人们在青少年晚期或20岁出头的年岁最容易长智齿,这时候人的年纪大了,也更有智慧,所以称之为智齿。

智齿属于臼齿,长在口腔后侧用来磨碎食物。通常口腔内没有足够的适于智齿生长的空间,因此他们常常会挤撞其他牙齿。有时甚至会侧面顶着牙龈生长。

无法长出或萌出的智齿称为阻生牙。仅有部分萌出的智齿周围容易产生细菌感染。

专家建议人们应在16-20岁之间检查智齿生长的位置。X光可以清楚地显示牙龈下智齿的情况,咬合不均衡或会成为阻生牙的多会被拔除。

美国牙医学会建议出现以下情况时将智齿拔掉:智齿无法完全萌出牙床时;咬合不均衡的智齿有可能侵犯邻牙时;流质食物残渣堆积堆积在部分或全部位于牙床以下的智齿时。

既然我们需要拔掉智齿,为什么还会长智齿呢?一个理论认为这与人类的饮食有关。科学家们介绍,远古时代,食物比较粗糙,人们需要更多的咀嚼类牙齿来帮助磨碎食物。

智齿拔除手术由牙医们完成。他们认为最好选择智齿尚未引起任何疼痛和问题的时候进行手术。

美国口腔颌面外科医师协会表示应尽量选择年轻时进行手术,年纪越大,引发臼齿周围组织感染的几率越大。

手术时可以选择全身麻醉,或者吃止痛药,保持清醒。这取决于智齿的情况以及要移除的数量。

手术后牙床和脸部会肿胀,并伴有疼痛。可使用冷毛巾或吃消炎药。