https://en.wikipedia.org/wiki/Paintless_dent_repair

…Dentology, is a branch of auto body repair, dealing with the removal of minor pressure blemishes to metal, through a scientific method, commonly referred to as paintless dent repair. It deals with, but is not limited to, the process of restructuring metal on a vehicle to its original state, after a minor impact or push. Dentology primarily deals with two types of dents, perforated and protruding, with two primary causes dynamic denting and quasi-static denting; together, they contain endless subcategories and varieties.^[5] This branch, defines a dent or ding as any discontinuity to a panels resistance and stiffness from its original factory setting. Which is typically created by hail damage (dynamic denting), or by structural frame resistance caused from “door slamming” to the outer shell (quasi-static denting)…