BOSTON — The state Attorney General’s Office has filed a lawsuit against Aspen Dental, which has an office in Pittsfield, alleging the dental chain cheated thousands of Massachusetts consumers through a series of bait and switch advertising campaigns.

The complaint, filed in Suffolk Superior Court, alleges that Aspen Dental violated the state Consumer Protection Law and the assurances Aspen Dental made to the AG’s Office in a 2014 settlement addressing similar conduct. According to the AG’s lawsuit, Aspen Dental engaged in numerous deceptive advertising and marketing practices — including charging patients for services it advertised as “free” and not living up to “guarantees” it advertised — as well as other deceptive practices in its interactions with consumers.

There are more than 25 Aspen Dental-branded dental offices in Massachusetts. According to the complaint, these offices brought in over $389 million in net patient revenue from December 2014 to January 2019. Aspen Dental’s Pittsfield office has been open since 2013.