back tooth; molar
front tooth; foretooth; incisor
奥歯が痛くて眠れない。
My back tooth aches so much I can't sleep.
虫歯で奥歯を抜くことになった。
My molar had to be extracted due to a cavity.
食事中、いつも奥歯に物が挟まる。
Food always gets stuck between my back teeth when I eat.