My mother goes to the dentist every other day for dental treatment.

Literal

Mother [topic-は] teeth [possessive-の] treatment [purpose-のために] one-day intervals [at-に] dentist [to-に] is-commuting-[polite-ます]

1日おきに = 'every other day' — おきに marks regular intervals. ために = for the purpose of. 通っています = 'is commuting/going regularly' — 通う implies repeated trips to the same destination.