OREANDA-NEWS. A.M. Best has upgraded the financial strength rating (FSR) to A (Excellent) from A- (Excellent) and the issuer credit ratings (ICR) to “a” from “a-” of Delta Dental of California (DDC) (San Francisco, CA) and its affiliate, Delta Dental Insurance Company (DDIC) (Wilmington, DE). The outlook for each of these ratings was revised to stable from positive.