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back tooth; molar
奥歯おくばが痛くいたくて眠れねむれない。
My back tooth aches so much I can't sleep.
虫歯むしばで奥歯おくばを抜くぬくことになった。
My molar had to be extracted due to a cavity.
食事しょくじ中ちゅう、いつも奥歯おくばに物ものが挟まるはさまる。
Food always gets stuck between my back teeth when I eat.