Sun Life Financial Inc., through its U.S. business, has entered into a definitive agreement to acquire DentaQuest, for US$2.475 billion. Headquartered in Boston and founded in 2001, DentaQuest is a provider of Medicaid dental benefits in the U.S. with Medicare Advantage, commercial and U.S. Affordable Care Act (ACA) exchange businesses. Upon close of the transaction,…