Abstract：Occlusion is a branch of oral science focusing on the physiological and pathological features of dental occlusion. It covers not only the morphology and physiology of occlusion，but also the clinical features of occlusion normality and abnormalities. An aberrant occlusion plays a role in temporomandibular disorders，bruxism，cervical spine disorder and periodontal problem（s）. It may play a part in tooth wear，tooth fracture，food impaction，dentinal hypersensitivity，mucosa bruise，allotriogeusia，fissured tongue and dyskinesia tongue. All these make the occlusion a source of some psychological symptoms. Currently，it is emergently necessary to investigate occlusion in a combination of views and methods of anatomy，physiology，biomechanics，molecular biology，pathology，etc.，based on which to develop the practical assessment systems，methods or techniques followed by a series of evidence-based therapeutic studies to draw up a guideline of occlusal treatment.
