The deleterious effect of dental caries (decayed teeth) and impacted teeth upon mental efficiency has frequently been asserted, usually on the basis of theoretical arguments rather than empirical data. It is unfortunate that some advocates of oral hygiene have made extravagant claims in its behalf, since if scientific verification of these claims should not be forthcoming, the legitimate objectives of dental hygiene may be placed in an unfavorable light. The writer recalls a case in point which came to his attention while serving as psychologist in the Ohio Institution for the Feebleminded in 1914. An imbecile with a mental age of about four years was committed from one of the larger cities of the state. Included among the commitment papers was a full page clipping from the magazine section of a Sunday newspaper which gave in great detail facts regarding the startling mental improvement of this patient following dental treatment during the preceding year. (B.L. Hathaway, 2001)
Photographic proof was included consisting of pictures of the patient "before and after treatment." In the photographs of the patient obtained before treatment the boy's expression is supposedly that of a mental defective, relaxed facial muscles, open mouth, and lack of alertness in the dull eyes which portrays after the manner of the movies, the typical low-grade imbecile. In the pictures taken after dental treatment the boy's face is wreathed in smiles and an alert, highly intelligent facial expression is depicted. Alertness, smiles, and eagerness transformed the dull, vacant stare into an expression which would do credit to the most precocious youngster. The falsity of the evidence for "a remarkable improvement in intelligence" which according to the claim in the article had taken place as a result of dental hygiene was now apparent. This kind of episode argues powerfully for caution when claims of sudden and quasi-miraculous mental improvement resulting from medical, surgical, or dental treatment are unsupported by adequate quantitative evidence.............
