Milk bottle decay is a severe, rapidly progressing form of decay affecting most, or all, of the baby teeth is caused by having sweet liquid in contact with the teeth for long periods of time (i.e. while the child is sleeping).
Sweet drinks are the main culprits but even juice and milk can cause decay if left in contact with the teeth for long enough.
Always make sure the child does not sleep with a feeding bottle. As this may cause the teeth to decay because of the sweetened milk in the bottle.
Children susceptible to milk bottle decay need regular dental monitoring and follow up to bring the decay under control and prevent the condition from getting worse.