Cephalometric Norms and Construction the Cephalometric Polygon in “Mazahua” Adolescents

The cephalometric polygon is a simple manner to determinate the skeletal and dental pattern of the patient, as well as growth trends, and the deviation degree of each patient. The indigenous groups in Mexico represent more than 10% Mexican population, including the “mazahua” ethnic group, the majority in the state of Mexico. Objective: to determinate the cephalometric norms and to construct the cephalometric polygon in “mazahua” adolescents by age and sex groups. Methods: Cephalometric norms based on 80 normal occlusion “mazahua” adolescents from the “El Fresno Nichi” village state of Mexico, Mexico were determinate. Twenty-six angular and 18 linear cephalometric measurements were obtained of each adolescent by age and sex group. The minimum and maximum value, average and standard deviation were compiled. Studentxs t-test was used for the comparison by age and sex groups. The average and deviation standard were used for the construction of the cephalometric polygon. The vertical center line through the polygon represented the average normal size. The variation range was constructed from the standard deviation. Result: Cephalometric findings showed a significative morphologic differences between both genders which is more evident in the early adolescence whit a more protrusive position in the relationships of the upper and lower basal arches in males (p<0.01) and a vertical growth in both genders, it was more representative in female group (p<0.05). At the late adolescence, females group showed a maxillar position significative more protrusive whit respect to the mandible (p<0.05). Regarding to dental pattern females were significantly more protrusive in both age groups than those in the male (p<0.05). Conclusions: Due to the differences found in both age groups, same norms are not applicable, reason why it was necessary the construction of the cephalometric polygon for each group of age and gender.