<P> Primary teeth start to form during the embryo phase of pregnancy . The development of primary teeth starts at the sixth week of tooth development as the dental lamina . This process starts at the midline and then spreads back into the posterior region . By the time the embryo is eight weeks old , there are ten buds on the upper and lower arches that will eventually become the primary ( deciduous ) dentition . These teeth will continue to form until they erupt in the mouth . In the primary dentition there are a total of twenty teeth : five per quadrant and ten per arch . The eruption of these teeth ( `` teething '' ) begins at the age of six months and continues until twenty - five to thirty - three months of age during the primary dentition period . Usually , the first teeth seen in the mouth are the mandibular centrals and the last are the maxillary second molars . </P>
<P> Primary teeth start to form during the embryo phase of pregnancy . The development of primary teeth starts at the sixth week of tooth development as the dental lamina . This process starts at the midline and then spreads back into the posterior region . By the time the embryo is eight weeks old , there are ten buds on the upper and lower arches that will eventually become the primary ( deciduous ) dentition . These teeth will continue to form until they erupt in the mouth . In the primary dentition there are a total of twenty teeth : five per quadrant and ten per arch . The eruption of these teeth ( `` teething '' ) begins at the age of six months and continues until twenty - five to thirty - three months of age during the primary dentition period . Usually , the first teeth seen in the mouth are the mandibular centrals and the last are the maxillary second molars . </P>
deciduous teeth begin to appear around the age of
deciduous teeth begin to appear around the age of
six months
six months