Why brushing teeth twice a day is not always best

From LearnAndRecord

We all think we know how to brush our teeth - a scrub morning and night, a rinse with water and maybe a minty mouthwash for good measure.

scrub-n./v.（用硬刷子，肥皂和水）刷洗；rinse-n.冲洗；minty-薄荷味的；mouthwash-漱口液

But according to dental experts, even the most diligent brushers might be making a few mistakes that could be undoing their good work.

*diligent-勤奋的，细致的，潜心的；

Dr Praveen Sharma, from the school of dentistry at the University of Birmingham, says that half of adults in the UK will have gum disease at some point and an early sign is bleeding gums.

gun-牙龈

"If your gums are bleeding or swollen it's a sign you need to brush better," he says.

swollen-肿胀的

As well as regular dentist visits, here are things he and BBC's What's Up Docs podcast hosts Dr Xand and Dr Chris van Tulleken, say many of us are currently getting wrong which if we change could improve the health of our teeth.

podcast-播客

Brushing once well is better than twice quickly

It's one of the great dental commandments - brushing twice a day - and that's what the NHS recommends.

dental-牙齿的；commandment-戒律，命令，an order

But Dr Sharma says the real key is quality, not quantity.

"If you can find time, then yes, brush properly twice a day," he says. "But it's better to do it once a day well and once quickly for two minutes.

If you only have time to brush and floss properly once a day then he recommends it be in the evening.

floss-n.牙线，v.用牙线清洁（牙缝）

Of course, no one likes flossing, but Dr Sharma says using interdental brushes can make it easier and less painful.

interdental-inter~dental牙齿间的

When it comes to the method, each tooth has an outer, biting and inner surface and all three need to be brushed.

Dr Sharma advises small circular motions over each surface without applying too much pressure. He also says to pay particular attention to the junction between the tooth and the gum as that's where gum disease can occur.

juction-连接点，汇合处

Dr Xand says it's important to "focus on the sensation of the bristles" and approach tooth brushing mindfully, not scrolling on your phone at the same time.

sensation-触觉，（感官的）感觉，轰动；bristle-短而硬的毛发，刷子毛；scroll-n.卷轴，v.上下滚动屏幕

Brush before breakfast, not after

Many people brush their teeth right after eating, but that might not be doing your enamel any favours.

enamel-釉质；favour-恩惠，善意，支持

"Ideally, brush before breakfast," Dr Sharma says. "You don't want to do it after something acidic.

acidic-酸性的

"If you do brush after, then you need to leave some space between eating and brushing."

That's because acids from foods and drinks, especially fruit juice or coffee, can soften tooth enamel and brushing too soon afterwards can wear it away.

Dr Chris suggests rinsing your mouth with water after eating to get rid of some acid and then waiting at least 30 minutes if you are brushing after breakfast.

Don't rinse after brushing

If you've been spitting, rinsing and gargling after every brush, you might want to rethink that last step.

*spit-吐口水，吐；gargle-漱喉；

"You spit but don't rinse with water," Dr Sharma advises. Rinsing your mouth washes away the concentrated fluoride in the remaining toothpaste.

fluoride-氟化物；toothpaste-牙膏

That means simply spitting out the excess toothpaste and leaving the thin layer of fluoride behind to continue protecting your teeth.

If you want to rinse your mouth after brushing, use a mouthwash.