Data from an interview and clinical examination in a study of 440 randomly selected school children were analyzed with regard to relationships between signs and symptoms of functional disturbances and diseases in the stomatognathic system. A correlation was found between reported clicking sounds from the temporomandibular joint (TMJ) and pain when opening the mouth wide. Children who had been treated orthodontically or who were undergoing such treatment did not differ from other children in the frequency of signs and symptoms. Correlations were found between recurrent headaches and tenderness in TMJ and TMJ muscles. Reported pain in the temple region was also correlated to tenderness in the TMJ and TMJ muscles. Further correlations were found between recurrent headaches and oral parafunctions such as lip—cheek-biting and nail-biting and also among nail-biting, tooth clenching, tooth-grinding, and frontal dental wear. Children who reported oral parafunctions had more frequent interferences in RP and tenderness in TMJ muscles. There were correlations between irregular movements of the lower jaw and interferences in RP as well as mediotrusion interferences. Finally, a strong correlation was found between tenderness of the TMJ (laterally and posteriorly) and tenderness of the TMJ muscles.