Tooth decay in infants and very young children is often referred to as baby bottle tooth decay. Baby bottle tooth decay happens when sweetened liquids or those with natural sugars (like milk, formula, and fruit juice) cling to an infant's teeth for a long time. ... They also serve as placeholders for the adult teeth. Is baby bottle tooth decay painful? Potential Complications of Baby Bottle Tooth Decay Pain and infection will likely result if a tooth is lost too early or if tooth decay is left untreated. In addition, if the baby teeth don't develop properly, your baby may develop poor eating habits or have speech problems. ... pain or difficulty chewing.