Inlays/onlays are tooth-colored ceramic fillings which are bonded onto the tooth surface. As compared to amalgam fillings, they are aesthetically pleasing and strengthen remaining tooth structure.
A bridge is a fixed dental prosthesis which relies on adjacent teeth for support to fit the "false" teeth on. In order to permanently cement the bridge onto the adjacent teeth, they would have to be trimmed down and resulting in irreversible loss of tooth structure. Removable dentures and dental implants are alternative options to bridges.
Retaining restorable teeth helps patients eat better, prevent shrinkage of bone height and keep teeth in proper alignment which would otherwise drift after extraction. Wearing a removable denture is sometimes uncomfortable, inconvenient and has to be changed every few years. In recent times, dentists actively advocate keeping restorable teeth as long as possible.
X-rays are important diagnostic aids employed by dentists today. With x-rays, well concealed dental conditions like decay in between teeth, gum infections and pathological lesions can be easily detected. Your dentist would probably explain to you valid reasons for taking dental x-rays.