Starting from the fact that stomatologic dispensarization in schools is the best method for evaluating morbidity by bucco-dental disorders in students, the authors present the results of a longitudinal study which consisted in the permanent monitoring of 48 students for a period of 8 years (1980-1988). The children were from the I-st to the VIII-th class. It is stressed that the most relevant indexes of morbidity are those of incidence (for the evaluation of the present potential of developing a disorder), and that of severity (for the assessment of the morbidity status). The authors intend to take up again this study, with the same methodology, in a group of students to which a local fluorination procedure was applied from the I-st scholar cycle.