<prompt> Eruption of 1st molar permanent tooth occurs at the age of4-5 yrs6-7 yrs7-8 yrs8-10 yrs  <response>: Eruption of permanent molar teeth: First molar upper jaw - 6-7 yrs First molar lower jaw -. 6-7 yrs Second molar upper jaw- 12-13yrs Second molarlower jaw-11-13yrs Third molarupper jaw-17-21yrs Third molarlower jaw-. 17-21yrs Hence, the eruption of first molar permanent tooth is at the age of 6-7 yrs. Ref: Ghai, 9th edition- Pg-11. 