I found these answers that might be helpful for you (I also thought it might have something to do with the problem of thumb sucking etc. that affects the growth of teeth but it seems to be mainly due to the possibility of decay):
What about bottle-feeding?
Where a child is bottle fed, you must sterilise the bottle properly. Never add sugar or put sugary drinks into the bottle. Bottle-feeding with drinks containing sugar can lead to 'bottle caries' (tooth decay). A baby is not born with a sweet tooth and will only have a taste for sugar if it is given at an early age.
When should I stop bottle- and breast-feeding?
Early weaning can help stop your baby from developing problems with their teeth that can be caused by drinking from a bottle.
Try to get your baby to drink from a special cup by the time they are about 6 months old, or when they are able to sit up and can hold things on their own.
From www.dentalhealth.org.uk
Baby Bottle Tooth Decay
Ahh ? those little pearly whites. After enduring weeks of teething pains, your baby?s toothy smile never fails to light up a room or warm your heart. But bright smiles can dim quickly if baby?s teeth are not cleaned and cared for correctly. Use these dental tips to keep your baby?s grin great and prevent baby bottle tooth decay.
Start early. Teething can begin as early as 4 months, but most babies won?t get their first tooth until about 6 months. Teeth often arrive in pairs, with the bottom front two showing up first, followed by the top two. Even before these tiny teeth show, you should massage your baby?s gums gently with a damp washcloth. This will help keep gums healthy and ease teething pain.
Say ?no? to a nightcap. Putting a baby to bed with a bottle, which he can suck on for hours, is the major cause of infant tooth decay. Baby bottle tooth decay, the leading dental problem for children under 3, occurs when a young child?s teeth are exposed for a prolonged period of time to sugary liquids, such as formula and fruit juices. As a result, the enamel on the baby?s teeth starts to dissolve, leading to decay and possible infection. This can even affect the development and spacing of permanent teeth.
Fortunately, you can prevent baby bottle tooth decay by following these recommendations from the American Academy of Pediatric Dentistry:
- Don?t allow your child to fall asleep with a bottle containing milk, formula, fruit juices or other sweet liquids.
- Never let your child walk with a bottle in her mouth.
- If your child wants a bottle between regular feedings or during naps, comfort her with a bottle filled with cool water.
- Always make sure your child?s pacifier is clean, and never dip a pacifier in a sweet liquid.
- Introduce children to a cup as they approach 1 year of age. Children should stop drinking from a bottle soon after their first birthday.
- Look for any unusual red or swollen areas in your child?s mouth or any dark spots on his teeth and consult a dentist immediately once they?re discovered.
Teeth-Care Tip
Don?t use fluoride toothpaste on your child?s teeth until at least 3 years of age, when she is old enough not to swallow the toothpaste. Ingesting toothpaste can result in tooth staining or surface irregularities on the enamel.
Don?t worry about your little one getting enough fluoride, an important compound that strengthens enamel and prevents tooth decay. Most cities and towns add fluoride to their water systems for this purpose. If your water comes from a well or you prefer bottled water (which doesn?t contain fluoride), ask your pediatrician or dentist about fluoride supplements.
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