| dc.description.abstract | Purpose
To evaluate soft tissue, dental, and skeletal cephalometric, craniofacial differences between three different ethnic populations – Mexican Americans, Nuevo León Mexican mestizos, and Yucatán Mexican mestizos.
Materials and Methods
The sample consisted of 274 untreated Class I subjects, including 91 Mexican Americans (43 males, 48 females), 89 Nuevo León Mexican mestizos (43 males, 46 females), and 94 Yucatán Mexican mestizos (36 males, 58 females) with the average age for males and females of 13.36 years and 12.96 years, respectively. Lateral cephalometric radiographs were collected for the samples and were calibrated. A custom analysis was created to analyze sixteen soft-tissue measurements, twenty-three skeletal measurements, and nine dental measurements. Univariate analyses of covariance (ANCOVAR) were used to evaluate the measurements based on geographical ancestry and sex and significance levels were corrected based on the total number of measurements.
Results
Males had significantly (p<0.007) more protrusive upper lips, thicker upper and lower lips and thicker soft tissue chins than females. There were no significant differences between males and females for any measurement of soft tissue convexity. Males were also significantly larger in all horizontal and vertical linear measurements compared to females. There were no significant sex differences for any of the dental measurements. Yucatán mestizos had more protrusive upper lips and soft tissue profiles than Nuevo León mestizos and had more protrusive lower lips than both Nuevo León mestizos and Mexican Americans. Mexican Americans had significantly (p<0.01) thicker upper and lower lips and chins than Yucatán and Nuevo León mestizos. Yucatán mestizos showed significantly (p<0.0125) more retrusive chins and were more skeletally convex (p<0.007) than Mexican Americans and Nuevo León mestizos. Yucatán mestizos were also significantly (p<0.007) more hyperdivergent than Mexican Americans. Nuevo León mestizos were found to be significantly (p<0.001) smaller than Yucatán mestizos and Mexican Americans for all vertical measurements. Mexican Americans were found to be significantly (p<0.001) larger for all horizontal measurements. Yucatán mestizos were found to have significantly (p=0.005) more upper incisor protrusion, and lower incisor proclination and protrusion compared to Mexican Americans. Mexican Americans had significantly more obtuse interincisal angles than both Yucatán and Nuevo León mestizos.
Conclusions
Current cephalometric norms cannot be applied to Mexican mestizo populations. Orthodontic diagnosis and treatment planning must consider mestizo soft tissue, dental, and craniofacial characteristics. Mestizo males have more protrusive upper lips, and thicker upper and lower lips than females. Males are generally larger than females. Males and females are the same dentally. Yucatán mestizos have more protrusive lips, but Mexican Americans have thicker lips than the other groups. Yucatán mestizos are more hyperdivergent, mandibular retrusive, and have a greater skeletal convexity than Mexican Americans and Nuevo León mestizos. Yucatán mestizos have more protrusive upper and lower incisors, and more proclined lower incisors than Mexican Americans and Nuevo León mestizos. | en |
