Any damage. The salvage title is a result of the insurance company paying a claim to the uninsured. They have to pay the insured as a total loss after a certain period if the car is not recovered.
Once a title is salvaged it can get a restored/rebuilt title if it’s determined by the state as road worthy. In Utah that means passing safety and emissions.
It’s literally impossible to get a salvage title back clean status even if it was never wrecked. Hope that helps. I owned a salvage dealership for several years.