<prompt> Which of the following are the first incisors to erupt in an infantLower centralLower lateralUpper centralUpper lateral  <response>: 4-7 months old: The first baby teeth usually begin to break through erupt the gums at around 6 months old.This can occur anywhere between four and seven months.As a general rule, the first teeth to erupt are the two in the front bottom.These are called the lower central incisors. 