Four main causes of bruxism have been studied - high anxiety level, malocclusion, temporomandibular disorders (TMD) and oral habits. Effective dental treatment for this problem is unknown in children with primary teeth, although, high prevalence has been reported. The aim of this study was to investigate the effectiveness of psychological techniques in children with bruxism. A total of 33 children, 3-6 years of age with normal occlusal features, without oral habits, rate in the Conners' parent rating scales (CPRS) and more than 0.75% in Conners' teacher rating scales (CTRS), and one or more temporomandibular joint (TMJ) disorders registered in the Bernal and Tsamtsouris examination, were selected from 188 children. Two psychological techniques, 'directed muscular relaxation' and 'competence reaction', were applied for 6 months. The results were analysed with a Wilcoxon rank sum test. All patients reduced their anxiety level and TMJ disorders, with statistical significance (P < 0.05). The psychological techniques were effective in the reduction of signs of bruxism in children with primary teeth.