[The relative factors of protrusive balanced occlusion and the relationship among them]

The experiment was designed to study the condition for achieving protrusive balanced occlusion and the factors involved in occlusal equilibration.

For achieving protrusive balanced occlusion, the posterior teeth of mandible always contacted with the posterior teeth of maxilla in the process of protrusive occlusive movement. The angle between the line of movement track of mandible cusp in the process of protrusive occlusive movement and occlusion plane is called cusp movement inclination. A formula of calculation was obtained by using mathematics track and the conversion of coordinate axis.

The focus of protrusive balanced occlusion is relationship between the track of mandibular cusp movement and working incline of maxillary cusp. The first condition achieving protrusive balanced occlusion is that cusp movement inclination is equal to cusp working inclination of maxilla. The factors affecting cusp movement inclination are condyle path inclination; incisal path inclination and teeth coordinate. The factors affecting working inclination of cusp are cusp inclination and long axis obliquity.

Cusp movement inclination is the basic and the most important concept in protrusive balanced occlusion.