[Secular trend as a factor of craniofacial morphological changes].

The study was carried out in two age-matched groups of patients from two different periods of time. The aim of the study was to determine whether any craniofacial system alterations attributable to the influence of secular trend had occurred during a defined period of time. Four basic craniofacial variables, from which the craniofacial indices were derived, were measured. The findings were statistically processed by the basic parameter evaluation and testing of differences of arithmetical means of the same variables between the two study groups. The results showed the following alterations to have occurred during a 13-year period due to the secular trend effects: cranial indices decreased, mostly by a significant cranial length increase (g-op); and facial indices decreased, mostly by a facial height decrease (n-gn).