The short answer to the question is no, dental crowns do not cause bone loss. As a matter of fact they have the chance of strengthening the jaw bones as they are usually placed in conjunction with dental implants. Missing teeth or teeth with weak or decayed roots may lead to bone loss as the tooth's integrity keeps the jawbone in shape. Getting implants to replace your missing or decayed teeth mimics the natural role of implants and creates incentive for the preservation of bone mass in the jaw.
Dental crowns by themselves have no effect on the underlying bone structure and therefore you are not at danger of bone loss by getting crowns. The two are actually so unrelated that the only instance it can affect bone loss by a dental operation that consists only of dental crowns has to do with tooth decay. The placement of a dental crown may decrease the chances of complete tooth decay by the removal of the area and thus help preserve bone mass by the preservation of the underlying tooth structure. Regardless, there are many advantages to getting dental crown treatment in turkey, you might want to look at them all before making your decision.