is a bottle at night bad for my babys teeth

Milk is good for babies; milk sitting on teeth for hours is not. The problem with a bottle at bedtime, or through the night, is not so much what is in it as when it is given and how long it stays on the teeth.

Why night-time is different

During the day, saliva constantly washes the teeth and neutralises acid. During sleep, saliva flow drops sharply. A baby who falls asleep sucking a bottle has milk, which contains natural sugar (lactose), pooling around the teeth with almost nothing to clear it. Bacteria in the mouth turn that sugar into acid, and the acid dissolves enamel. Repeat that every night for months and the result is what dentists call early childhood caries, or nursing bottle caries.

Many families add sugar, honey or malted health-drink powders to the bedtime bottle to help a child settle. These make the damage much faster. Juice, sweetened lassi and diluted fruit drinks in a bottle are worse still.

What it looks like

• First: dull, chalky white lines along the upper front teeth, near the gums. Easy to miss.
• Next: yellow or brown patches that become soft and start to crumble.
• Later: front teeth that break down into brown or black stumps, sometimes with pain, swelling or a gum boil.

The lower front teeth are usually spared at first, because the tongue covers them during sucking. This pattern, with upper front teeth affected while the lower ones look fine, is typical.

What about night breastfeeding?

Breastfeeding has many benefits, and this is not a reason to stop. But once teeth are in, frequent feeding through the night can also contribute to decay, especially if the child also has sugary foods during the day. Gently wiping or brushing the teeth after the last feed, and not letting an older baby sleep latched on all night, reduces the risk. Discuss what is practical for your family with your paediatrician.

Practical ways to change the habit

• Give the last milk feed before brushing, not in bed. Brush, then sleep.
• If a bottle is part of the sleep routine, switch to plain water. Some parents dilute the milk a little more each night over a week or two until it is just water.
• Never add sugar, honey, jaggery or health-drink powders to a bottle.
• Don't let your child walk around sipping from a bottle all day either; how often teeth meet sugar matters as much as night-time.
• Start offering an open cup or a sipper from around six months.
• Grandparents, nannies and house help are often the ones giving the night bottle. Make sure everyone who puts your child to bed knows the plan.

If you already see white or brown spots

Don't panic, and don't feel guilty; this is very common. Early chalky white spots can often be stopped or even reversed with fluoride toothpaste, professionally applied fluoride and changes to feeding. Brown or soft areas need a dentist's assessment soon, because decay in milk teeth spreads quickly. For children under 10, ask for our paediatric dental specialists. Read more on our decay in milk teeth page, or see when to stop the bottle on our kids' dentistry hub.