牙釉质是牙齿坚硬的外层。

　　The cavity gets larger by entering the softer second tooth layer, the dentin.

　　蛀牙洞到了牙齿的较软的第二层， 也就是牙本质时，龋洞就会变得大的多。

　　Does decay affect the dentin?

　　蛀牙对牙质有影像吗？

　　Decay spreads quickly when it reaches the dentin.

　　蛀牙到了牙质时发展的很快。

　　The decay must be removed at this time because it'll soon reach the sensitive tooth pulp.

　　这时候应该把蛀牙治疗，因为不久它就会侵入到很敏感的牙髓。

　　有关龋齿的解释.jpg

　　If this happens, there'll be death of the pulp, pain and infection into the jaw-bone surrounding the tooth.

　　要是蛀牙到了牙髓，牙髓就会坏死，牙齿四周的颌骨就会疼，就会发炎。

　　The tooth might have to be removed if this happens.

　　在这种情况下，这颗牙齿就要拔掉。

　　How can I prevent this?

　　该怎样预防呢？

　　It's absolutely necessary to visit your dentist twice a year for dental check up to prevent infection and loss of teeth.

　　那就肯定要一年去看两次牙医， 进行检查， 预防感染， 也预防牙齿脱落。

　　X-rays are a very important Part of a dental examination.

　　照 X光进行牙科检查的一个重要部分。

　　X-rays are needed to find decay that's hidden from sight.

　　检查看不见的蛀牙需要看X光。

　　What type of X-rays do you usually take, Doctor?

　　你通常使用的是什么种类的X光？

　　I usually take two different kinds of X-rays when I examine a patient.

　　我通常用两种不同种类的X光检查病人。

　　Periapical X-rays are needed to be able to examine the roots of teeth.

　　检查牙根时需要进行齿根周围的X光照射。

　　It also is needed to examine the surrounding tissues for signs of periodontal disease, impacted teeth, infections and cysts.

　　也需要检查牙周围的组织，找牙周病，嵌入牙， 感染和囊肿的征兆。

　　Does this X-ray find the cavities?

　　进行X光照射能发现蛀牙吗？

　　This type of X-ray is not always effective for finding caries.

　　进行这种X光照射并不是一定有发现蛀牙的效果。

　　Cavity disclosing (bite-wing) X-rays are needed to supplement the periapical X-rays so that tooth decay can be diagnosed accurately.

　　需要用合牙翼片X光照射法作为齿尖周围X光照射法的辅助， 以便对蛀牙做出正确的诊断。