Babies typically start teething around 6 months of age , though there is a wide range of normal variation. Some babies may begin teething as early as 3 or 4 months, while others may not get their first tooth until after 12 months. It's even possible, though rare, for some babies to be born with teeth. The first teeth to appear are usually the lower front teeth (central incisors) , followed by the upper front teeth. Most babies will have their first teeth by their first birthday and typically have all their primary (baby) teeth by around 2 to 3 years of age. Signs of teething can include increased drooling, gum swelling, fussiness, biting on objects, and disturbed sleep. The entire teething process can last for about 2 to 3 years as all 20 primary teeth come in.