age of molars
1 The most common teeth sealed are the permanent molars. 2  These molar teeth arrive about 6 years of age and often have deep grooves on the chewing surfaces. 3  Tooth brushing cannot clean these grooves properly. 4  Over the years it has been reported that many of these new molar teeth will get tooth decay.
Front diastema: At your age, it's unlikely to close and certainly won't because your second molars are growing in. Second molars grow in around the age of 12. They are probably your wisdom teeth and still won't cause the gap to close. See a dentist about whether or not you have room for your wisdom teeth to fully erupt as well as options to close the gap.