Teething is the process uring which an infant's teeth start to sequentially grow in. Teething can start as early as three months or as late, in some cases, as twelve months. Occasionally a baby may even present with one or more teeth at birth. The typical time frame for new teeth to appear is somewhere between six and nine months. It can take up to several years for all 20 deciduous (aka "baby" or "milk") teeth to emerge. The process of teething is sometimes referred to as "cutting teeth".