Eyes of Children (1956)

Shunji Mitamura's wife died very early and left him a young son. Shunji's sister Hideko decided to fulfill her sisterly duty and moved to the main character to take care of the boy and the house. Time passes and Shunji marries Mieko Takamine. But since her father is often ill, she spends a lot of time in his dental clinic to do his work.