睡前偷懒不刷牙 VS 早饭吃完才刷牙，哪个更伤牙？
双语君约 5 分钟After a long day, skipping brushing your teeth before bed can feel tempting. Mornings can be just as rushed, with little time to clean your teeth. But if one habit is worse than the other, the answer is clear: missing your nighttime brushing does far more harm.
Brushing before bed can be seen as the most important line of defense for oral health.
睡前不刷牙，相当于给细菌“开派对”
我们的口腔里，本来就住着成千上万的细菌。它们最爱吃的，就是我们牙齿上残留的食物碎屑。吃完之后，细菌会排出酸性物质，慢慢腐蚀牙齿最外层的“盔甲”，即牙釉质。时间久了，蛀牙就找上门了。
The mouth naturally contains hundreds of thousands of bacteria. These microbes feed on food debris left on teeth, breaking it down into acids that gradually erode the enamel, our teeth's protective outer layer. Over time, this process leads to demineralization and increases the risk of cavities.
debris /dəˈbriː/ 碎片，残片
enamel /ɪˈnæm.əl/ 牙釉质
Under normal circumstances, regular brushing, eating, rinsing, and drinking help keep bacterial buildup in check. Brushing physically removes bacteria from tooth surfaces, while saliva helps wash away food particles and acts as a buffer that neutralizes acids and regulates bacterial growth.
saliva /səˈlaɪ.və/ 口水，唾液
When brushing is skipped before sleep, bacteria are left undisturbed for hours, allowing them to accumulate and damage the teeth. This prolonged exposure increases the risk not only of cavities but also of gum disease, bleeding gums, and bad breath.
早餐后刷牙：吞下细菌问题不大
What happens if you skip brushing in the morning before breakfast?
Upon waking, the mouth typically has a higher bacterial load, with plaque accumulating on the teeth. However, swallowing some of this bacteria during breakfast generally poses minimal risk, especially compared with leaving bacteria on the teeth overnight.
That said, this does not mean morning brushing is unnecessary. While chewing and saliva can help reduce plaque after a night's rest, they are far less effective than proper brushing and flossing. Cleaning your teeth in the morning remains an important part of maintaining oral health.
睡前必须刷，早上最好刷
① 睡前一定要认真刷牙
② 早晚各刷一次，最好不偷懒
来源：科普中国
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