A method of creating a retainer for engaging gums and teeth of a specific user. The method includes, at an initial step, creating a mold of the gums and teeth of the specific user. Indentations are placed into the mold along a gum-line between modeled gums and teeth. Subsequently, and using the mold with the indentations, a retainer is formed, such that the retainer includes protrusions, each of the protrusions corresponding to one of the indentations. The retainer matches the shape of the teeth and the gums of the specific user except for the protrusions, and when the retainer is worn by the specific user, the protrusions push on the gum-line of the specific user, thereby ensuring engagement of the retainer to the teeth and the gums of the specific user.
