Fig. 1

A Illustration of different levels of occlusal coverage depth (OCD). A lower level of OCD leads to less splint extension into the tooth embrasure (left, upper), while the higher level of OCD leads to more splint extension into the tooth embrasure (left, lower). For final splints (FSs), the upper and lower outer surfaces were determined by translated PLANE O (green dashed line). For intermediate splints (ISs), the upper and lower outer surfaces were determined by translated PLANE U₁ (red dashed line) and PLANE L₁ (blue dashed line), respectively. A constant 2 mm distance exists between PLANE U₁ and PLANE L₁. OCDs of the splints were determined by the sum of OCDs of the upper dentition (OCD-Us) and OCDs of the lower dentition (OCD-Ls). B Upper surface (left) and lower surface (right) of the physical splints. C The dentitions were occluded with the FSs (upper) or ISs (lower) and fixed with latex elastics