Does a secular trend exist in the distribution of occlusal patterns?

The existence of a secular trend in the distribution of occlusal patterns was studied in two generations of children. Study models and demographic data of a sample of 265 children from the previous generation (group A) and recordings of clinical examinations of 988 children from the present generation (group B) served as the data base for this study. Children in whom caries affected the occlusion and those in the deciduous dentition stage were excluded. Thus, occlusal analysis was performed for 102 children in group A and 703 in group B. A dramatic decrease was found in the prevalence of caries affecting the occlusion. No difference existed between the two groups with respect to molar and canine anteroposterior relationships. However, there was a decrease in the prevalence of normal occlusion accompanied by an increase of Class I malocclusion.