Bain Capital LP, through its impact investing arm, purchased HealthDrive Corp. from fellow Boston-based private equity firm Riverside Partners LLC for an undisclosed amount.

HealthDrive, which was bought by Riverside in 2008, provides on-site dentistry, optometry, podiatry and audiology services to residents across more than 2,000 long-term care, skilled nursing and assisted living facilities.

The deal should help HealthDrive broaden its service offerings and build a multispecialty healthcare platform for extended-care patients, Bain Capital Double Impact said in a release.