The “sixth age teeth” are the first permanent molars of the four large teeth that grow at the back end of the second molar around the age of 6. They are very important for the development of the child’s face and jaw, maintaining the bite relationship between the upper and lower teeth, and maintaining the shape of the face. Parents often mistakenly believe that they will be replaced, and neglect to protect them. Nowadays, the four “sixth-age teeth” are the most commonly encountered in clinical routine extractions and fillings.