The temporary teeth are replaced with permanent teeth on average at age of 6 to 7 years. The first to go are lower central incisors, which were the first ones of the primary teeth. The tooth eruption starts following the same sequence as was the initial growth i.e., the central two lower incisors and onward.

All temporary teeth are replaced with permanent teeth by the time child reaches the age of 12 years. Primary and secondary molars are replaced too. The third set of molars appears at age of 18 years and above and the fourth and last including the wisdom tooth appears much later at almost 25 years and above.

Permanent teeth are yellowish naturally, often appear with jagged edges (mamelons) and the placement also is not absolute. In some cases however they are more displaced and can only be fixed through orthodontic treatment (braces).  The mamelons wear down themselves or otherwise you can consult a dentist who can trim them.