INTRODUCTION: Bruxism is an involuntary parafunctional, rhythmic and spasmodic activity of the masticatory system produced by rhythmic or tonic contractions of the masseter and other mandibular muscles and characterized by the grinding or clenching of the teeth during both daytime and nighttime periods. Bruxism can occur consciously, when biting pencils or fingers, or unconsciously. The act of ranger within the period, periods of worry, stress and excitement, accompanied by a remarkable noise. They have been perfected, in general, without noise, are more common in time and can be considered more destructive, since they are the forces are continuous and less tolerated. OBJECTIVES: to investigate an occurrence of bruxism in early childhood and to know the factors that are related to oral habits related to motor and chewing functions as well as to investigate an association in the function of gender and age. METHODS: 100 questions and answers from 100 patients, aged 6 to 12 years, of both sexes and ethnicities were applied to evaluate the prevalence and type of bruxism. RESULTS: it was as well as its association with the opening of teeth and presence of clicks in the region of the temporomandibular joint.