Gnathology is the study of the functional union of the whole masticatory system – teeth, jaw-bones, mandibles, temporomandibular articulation, masticatory muscle – which specializes on examining static and dynamic contact of teeth to diagnosis and therapy of pathological changes of temporomandibular articulation. Unfortunately nowadays diseases of temporomandibular articulation, headaches and neck-aches connected to them are more frequent. The new 3-D dental CT makes possible diagnose deviations of joints and cervical vertebra which have not been discovered so far. With model analysis of facial arch jaw movements can be reconstructed perfectly – biting, grinding movement – by this way pathological processes can be discovered. On the basis of it the most effective therapy for stopping increased tooth erosion, teeth grinding, teeth grasping, or jaw problems can be selected.