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 film, and it appears on the soundtrack. Capitol Records released "Something New" a month later with songs from the UK version of "A Hard Day's Night" that were not used in the film. The songs were also later released by Capitol on the "Hey Jude" compilation album in 1970. "I Should Have Known Better" was released as a single in a number of continental European countries, including Norway, where it reached number 1, and West Germany, where it reached number 6. In Sweden, the song topped the Kvällstoppen Chart for four weeks. The song is performed in the train compartment