Abstract
The etiology of bruxism has been related to two factors by Ramfjord: occlusal interferences and the psychic make-up of the individual. An occlusal interference is defined as: occlusal contacts hampering or hindering smooth, gliding, harmonious jaw movements with the teeth maintaining contact. The occlusal interference may involve one tooth or a number of teeth. It may occur on natural tooth structure or restorations. A premature contact or occlusal interference is usually avoided during mastication. This conforms to the general "convenience" principle of maximum intercuspation with avoidance of pain. | Frequently the pattern of mastication will be such that little or no irritation is placed on the involved tissues. In such instances the potential for pathology exists. In the case of bruxism, a different situation exists. | Instead of an interfering tooth being avoided, there is a tendency to seek it out and rub on it. The interference may initiate muscle hyperactivity. The interference becomes so objectionable the normal capacity of the neuromuscular system to adapt is exceeded. The irritability threshold of the neuromuscular system may be altered by such factors as emotional or psychic tension (e.g., anger, fear, and repeated aggression).