牙齒天然是黃色？

文/路易絲·邦德 譯/付迎杰 常海潮

You may long for a whiter smile, but are teeth naturally yellow? In a world where tooth whitening is increasingly common, especially among those in the public eye, it can be easy to forget what natural teeth look like.A study showed that up to 61% of Americans wish they could change the appearance of their teeth with a lack of whiteness coming out on top.

你可能渴望笑起來的時候牙齒顯得更白，但牙齒天然就是黃色的嗎？牙齒美白越來越普遍，尤其是在公眾人物當中，在這樣的形勢下，我們很容易忘記牙齒天然的樣子。一項調研表明，多達61%的美國人希望改變牙齒的外觀，嫌牙齒不夠白位居榜首。

2Despite many Americans having concerns about the appearance of their teeth, the average person only brushes their teeth for 45 to 70 seconds a day in findings from the Academy of General Dentistry.Experts recommend brushing teeth twice a day for two minutes.Maintaining good oral hygiene is an important factor in the appearance of your teeth.

2盡管許多美國人在意他們的牙齒外觀，但全科牙醫學會的調查結果顯示，一股人每天只刷牙45 到70 秒。專家建議每天刷牙兩次，每次刷兩分鐘。保持良好的口腔衛生是影響牙齒外觀的一個重要因素。

3In this article, we will dive into the science behind the color of our teeth.We look at whether yellow teeth are a sign of poor health, and what you can do to improve the appearance of yellow teeth.

3在本文中，我們將深入探討牙齒顏色背后的科學。我們看看牙齒發黃是否是健康不佳的標志，以及人們可以做些什么來改善牙齒發黃的狀況。

Are teeth naturally yellow?

牙齒天然就是黃色的嗎？

4那么，牙齒本來是黃色的嗎？想了解更多信息，我們首先要深入了解牙齒的構成。它們由三個不同的層組成。牙釉質是人體內最堅硬的物質，形成了最外層；牙本質在中間；最內層是牙髓。很少有人意識到是牙本質（牙齒的中間層）賦予了牙齒顏色。對大多數人來說，牙本質是淡黃色，但紅色調或琥珀色調也屬正常。

4So, are teeth naturally yellow? To find out more, we first need to delve into the composition of our teeth.They are made up of three different layers.Enamel is the hardest substance in the human body and forms the outermost layer, dentin is in the middle and the innermost layer is pulp.Not many people realize that it is the dentin, the middle layer of a tooth, which gives it color.For most of us, the dentin is a pale yellow but shades of red or amber are normal too.嗎？想了解更多信息，我們首先要深入了解牙齒的構成。它們由三個不同的層組成。牙釉質是人體內最堅硬的物質，形成了最外層；牙本質在中間；最內層是牙髓。很少有人意識到是牙本質（牙齒的中間層）賦予了牙齒顏色。對大多數人來說，牙本質是淡黃色，但紅色調或琥珀色調也屬正常。

5The color that we see is often more about the thickness of the enamel than the color of our teeth.

5我們看到的顏色通常更多反映了牙釉質的厚度，而不是牙齒的顏色。

6While there may be variation in the color of our teeth even from an early age, most people’s primary teeth appear whiter than their adult teeth.Dr.Sameet Hindocha explains that primary teeth appear whiter “because the enamel of babies’ teeth is thicker, which hides the yellow of the dentin underneath.”

6雖然我們的牙齒顏色可能從很小的時候就有差異，但大多數人的乳牙看起來比他們的恒牙更白。薩米特·欣多查醫生解釋說，乳牙看起來更白，是“因為嬰兒牙齒的牙釉質更厚，掩蓋了下面牙本質的黃色”。

Are yellow teeth a sign of poor oral health?

黃牙是口腔健康不良的標志嗎？

7牙齒發黃是很自然的事情，不一定是口腔健康不良的跡象。即使擁有健康的生活方式，無法控制的因素也會影響我們牙齒的外觀，例如基因和牙釉質厚度。隨著年齡增長，牙齒通常會越來越黃，這是衰老過程的一部分。欣多查醫生在接受美國趣味科學網采訪時說：“隨著年紀增加，我們的牙釉質會變薄或分解，這意味著牙齒內部的部分會更多地顯示出來，使牙齒看起來更黃或奶黃。此外，茶和咖啡等一些食物和飲料的染色也會導致牙齒變黃。”黃牙不一定是口腔健康不良的標志，但有時候這也可能表明牙釉質已被侵蝕，此時牙齒可能很脆弱并容易缺壞。

7It is perfectly natural to have yellow teeth and this is not necessarily a sign of poor oral health.Even with a healthy lifestyle, factors outside of our control can affect the appearance of our teeth such as our genes and the thickness of our tooth enamel.Our teeth often appear more yellow over time as part of the aging process.Dr.Hindocha told Live Science: “As we get older, our enamel thins or breaks down which means that the inner part of the tooth shows through more, making the teeth appear more yellow or creamier.Additionally, staining from certain foods and drinks, including tea and coffee, can also contribute towards the yellowing of teeth.” Yellow teeth are not necessarily a sign of poor oral health, though in some cases it may signal that the enamel has eroded and that the teeth could be weak and prone to chipping.

8Dr.Hindocha added: “There are a number of other factors which may affect the color of our teeth.Silver fillings can discolor the teeth grey as they release ‘corrosion’ products over time.Teeth that have suffered from trauma or dental abscesses may also appear darker over time as the nerve may die away and require treatment.Some people may genetically have discoloration of their teeth and this is usually related to discoloration inside the tooth.” A study in theBritish Dental Journalshows that some metabolic disorders are associated with tooth discoloration as well as the use of medications like tetracycline.

8欣多查醫生補充說：“還有許多其他因素可能會影響牙齒的顏色。銀質填充物會使牙齒變灰，因為它們會隨著時間的推移釋放出‘腐蝕’產物。受過外傷或牙膿腫的牙齒也可能隨著時間的推移顯得更黑，因為牙齒神經可能壞死并需要治療。有些人的牙齒可能會有遺傳性變色，這通常與牙齒內部變色有關。”《英國牙科雜志》刊登的一篇論文表明，一些代謝紊亂或使用四環素等藥物與牙齒變色有關。

9Our lifestyle choices can also influence the color of our teeth.Smoking can cause teeth to yellow rapidly.The tar and nicotine in tobacco are responsible for this staining effect.Coffee, red wine, chocolate, and fizzy drinks can all contribute to discoloration.

9我們選擇的生活方式也會影響牙齒的顏色。吸煙會導致牙齒迅速變黃，是煙草中的焦油和尼古丁造成的這種染色效果。咖啡、紅酒、巧克力和碳酸飲料都會導致牙齒變色。

What can you do about yellow teeth?

10While yellow teeth are not necessarily unhealthy, for many people the appearance of their teeth can affect their confidence.Luckily, there are changes we can make to improve how our teeth look.Maintaining good oral hygiene is an important preventative strategy.Experts recommend regular tooth brushing and flossing, plus mouthwash can be beneficial.

黃牙怎么辦？

10雖然黃牙不一定意味著不健康，但對許多人來說，牙齒的外觀會影響他們的自信。幸好，我們可以做出一些改變來改善牙齒外觀。保持良好的口腔衛生是一項重要的預防策略。專家建議有規律地刷牙和使用牙線，另外，漱口水也有好處。

11Lifestyle changes can help improve the appearance of your teeth.Quitting smoking can make a huge difference, as can reducing consumption of food and drinks which stain the teeth such as coffee.

11改變生活方式有助于改善牙齒外觀。戒煙有很大作用，減少攝入咖啡等會使牙齒染色的食物和飲料也有幫助。

12You should be aware that tooth whitening treatment does not change the color of fillings and crowns; these would need to be replaced if you wanted to change their appearance.Common side effects of tooth whitening are sensitivity and gum irritation.Dr.Safa Al-Naher warns against procedures carried out by non-dental professionals or without a prescription.She explained that:“They do not have the same accountability to a professional organization so there is a risk the product may not be safe and could cause damage.” ■

12要明白，牙齒美白治療不會改變填充物和牙冠的顏色。如果想改變它們的外觀，就要換掉這些。牙齒美白的常見副作用是牙敏感和牙齦刺激。莎法·納赫爾醫生提醒，不要由非牙科專業人員或在沒有處方的情況下進行治療。她解釋說：“他們不像專業組織那樣承擔責任，因此產品可能存在風險，并可能造成牙齒損壞。” □