Eighty-two dental patients were interviewed at the beginning of treatment in order to assess a number of psychosocial variables relevant to the prediction of compliance with treatment recommendations. Treatment consisted of cleaning, depuration and motivation. The patients were followed up after six months by measuring the development of plaque, calculus and gingivitis. In support of our hypothesis, it was found that variables that were related to patient involvement contributed strongly to the prediction of the oral health variables. The patient's visiting habits and initial attitudes were of particular prognostic value. The results with a set of variables conceptually unrelated to patient involvement were mixed and generally not as positive. Attendance at follow-up was predicted equally well by both kinds of variables, but generally not by the same variables as those that predicted oral health.