Compare valplast flexible vs. metal single tooth denture for chewing & hot/cold drinks? do they have different affects?

Consider: For single tooth replacement, a removable bridge is a really bad choice. These devices are very small and you risk either swallowing or aspirating the removable bridge. Plus they place additional forces on the teeth they attach to, with possible subsequent loosening of those teeth. Talk to your dentist about dental implant.

Hands down!: Replacing a single tooth with a flexible removable is silly, unless you really can't afford anything else and it is a front tooth that shows, or used for a short temporary replacement. A single implant supported crown is the best way to go, hands down! an implant crown will look and feel like your own tooth and last decades or a lifetime. A flexible partial will collect food, be annoying, etc.

A poor solution: The two types of removable partial dentures that you discribed can be classified as a nesbit type of prosthesis. In many states this type of prosthesis is considered malpractice due to the many inherent risk that you are taking by wearing one. The metal one may do less damage to surrounding teeth, but both are a poor solution to your problem. Consider other less risky alternatives.

none: If you are only replacing one tooth i would not do so with a removable device. A tooth partial typically does not work well for anything except cosmetics.