Guardian Life Insurance Company of America has acquired Preferred Dental L.L.C., a dental provider network.

Preferred Dental, Las Vegas, has contracts with about 800 Nevada dentists, according to Guardian, New York.

Guardian will emerge from the deal with 1,050 “unique network dentists” in Nevada.

The deal also should improve dental network provider discounts in Nevada by 6%, Guardian says.

In other insurance acquisition news:

- Principal Financial Group Inc., Des Moines, Iowa (NYSE:PFG), and Banco do Brasil S.A., Rio de Janeiro, have agreed to extend the BrasilPrev Seguros e Previd?ncia S.A. pension and long-term asset accumulation joint venture in Brazil.

BrasilPrev will have the exclusive right to manufacture and distribute products within the Banco do Brasil network for 23 years, according to Principal and Banco do Brasil.

BrasilPrev now has about $16 billion in assets under management in 3 million consumer accounts.

Principal will own 50.01% of the common stock of the joint venture, and Banco do Brasil will own 49.99%, the companies say.

Principal’s economic interest, or share of profits, will be 25.005%. In the past, Principal’s share of profits was 46.01%.

- Wells Fargo Insurance Services Inc., a unit of Wells Fargo & Company, San Francisco, has acquired AIM Administration Inc., Salt Lake City, an employee benefits brokerage.

Wells Fargo Insurance is not saying how much it is paying for AIM.

AIM provides group medical and dental plans and related ancillary benefits and consulting services.

AIM brokers will be moving into to Wells Fargo Insurance’s offices in Salt Lake City and Ogden, Utah, Wells Fargo Insurance says.

Brad Kuhnhausen, the managing principal of AIM, will be working with Wells Fargo Insurance as a consultant.

- EHealth Inc., Mountain View, Calif. (NASDAQ:EHTH), a Web-based insurance broker, has acquired PlanPrescriber Inc., Maynard, Mass., a privately held Medicare health coverage and prescription coverage shopping tool firm, for about $29 million in cash.

Ross Bair, the chief executive officer of PlanPrescriber, will continue to manage PlanPrescriber, eHealth says.