Varies.... This answer depends on several factors, including the number of teeth to be replaced, the condition of the adjacent teeth, among others. Fixed bridges tend to function more efficiently in general. I would visit your dentist for more specific answers.
Fixed bridge. The fixed bridge iwould resemble your natural dentition, a removable prosthesis requieres support for the gum, that make more difficult for the pt to get used to it.
Fixed. Fixed is generally preferable, if the support teeth are properly aligned and strong enough to support thr extra load. An implant would be best if possible.