“…The analysis of the OS devices’ characteristics revealed two main broad categories in which the OS can be grouped: (1) custom-made [ 4 , 5 , 15 , 18 , 22 , 23 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ] and (2) commercial products [ 30 , 31 , 32 , 33 , 39 , 40 ] ( Table 2 ). If for the commercial OS the personalization is limited (e.g., boil and bite OS) [ 38 ] or not possible (e.g., self-fit OS) [ 30 ], the custom-made splints can be tailored specifically on subjects’ mouth characteristics through dental impression stone or wax models (see, e.g., in [ 15 , 23 ]), semi-adjustable articulators (see, e.g., in [ 39 ]), or by digital reading models (see, e.g., in [ 18 ]). Five studies compared the impact of custom-made vs. commercial OS [ 31 , 32 , 33 , 39 , 40 ].…”