Deciduous teeth first teeth seen in the mouth are the mandibular centrals and the last are the maxillary second molars. The primary teeth are made up of central incisors, lateral incisors, canines, first molars, and secondary molars; there is one in each quadrant, making a total of four of each tooth. All of these are gradually replaced with a permanent counterpart except for the primary first and second molars; they are replaced by premolars. The replacement of primary teeth begins around age six, when the permanent teeth start to appear in the mouth, resulting in mixed dentition. The erupting permanent teeth cause
I Should Have Known Better I Should Have Known Better "I Should Have Known Better" is a song by English rock band the Beatles composed by John Lennon (credited to Lennon–McCartney), and originally issued on "A Hard Day's Night", their soundtrack for the film of the same name released on 10 July 1964. "I Should Have Known Better" was also issued as the B-side of the US single "A Hard Day's Night" released on 13 July. An orchestrated version of the song conducted by George Martin appears on the North American version of the album, "A Hard Day's Night Original Motion Picture Soundtrack". In January