Cephalometric comparison of a sample of Mexican Mestizo adolescents treated in México and a sample of Caucasian adolescents from The Tweed-Merrifield Long-Term Study, both treated with Tweed mechanics.

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Title:	Cephalometric comparison of a sample of Mexican Mestizo adolescents treated in México and a sample of Caucasian adolescents from The Tweed-Merrifield Long-Term Study, both treated with Tweed mechanics.
Alternate Title:	Comparación cefalométrica de una muestra de adolescentes mexicanos mestizos tratados en México y una de adolescentes caucásicos tratados en el Estudio a Largo Plazo de Tweed-Merrifield, ambos con mecánicas de Tweed.
Authors:	Gómez Palacio-Gastélum, Marcelo¹ gporthodgo@yahoo.com.mx, Vargas-Chávez, Nohé¹, Manuel Salas-Pacheco, Sergio¹, Salas-Pacheco, Manuel¹, Tremillo-Maldonado, Omar¹, Yamile Rivas-Escobedo, Andrea²
Source:	Revista Oral. may-aug2026, Vol. 27 Issue 84, p2581-2586. 6p.
Subjects:	Corrective orthodontics, Longitudinal method, Craniometry, Teenagers
Geographic Terms:	Mexico
Abstract (English):	Introduction. Dr. Charles Tweed's became world famous with his technique of transforming patients with protrusive faces into patients with pleasing facial contour. He developed the diagnostic facial triangle and stressed the importance of it. Objective. To compare a sample of Mexican Mestizo adolescents treated in México and a Caucasian adolescent sample from The Tweed-Merrifield Long-Term Study, both treated with the same Tweed mechanics. Methodology. The sample consisted in a total of 57 Mexican Mestizo patients, 35 girls and 22 boys with a mean age of 12.61 years, Angle Class I and Class II treated with standard Edgewise mechanics by a specialist (M.G.P.G.). Records of these patients were matched by age (± 6 months) sex, malocclusion and were compared to 57 American whites with a mean age of 13.24 years Class I and Class II patients treated with standard Edgewise mechanics from the Charles H. Tweed Foundation Long Term Study. The cephalograms of the two samples were traced, digitized, and analyzed by descriptive cephalometric analysis. Results. Tweed Triangle variables were not different between the groups at the start of treatment, whereas uprighting of the lower incisor FMIA and IMPA angles were statistically significant at the end of treatment (p < 0.05). Conversely, when comparing the start and finish records between Mexican Mestizo and Caucasians, lower incisors uprighting in the former was almost twice the amount of the latter, Caucasians FMIA 7.92° versus 3.91°, (p < 0.05); IMPA-6.35° versus -3.66° (p < 0.05). Conclusions. Mexican Mestizos were treated to a straighter profile to render a greater improvement, but well into Tweed's normal range at the completion of treatment. Both the Mexican Mestizo and Caucasian samples were treated according to the same principles enunciated by Tweed many years ago: the lower incisors were uprighted over the basal bone in order to achieve facial balance and harmony. [ABSTRACT FROM AUTHOR]
Abstract (Spanish):	Introducción. El Dr. Charles Tweed alcanzó fama mundial gracias a su técnica para transformar a pacientes con rostros protrusivos en pacientes con un contorno facial armonioso. Desarrolló el triángulo facial diagnóstico y destacó su importancia. Objetivo. Comparar una muestra de pacientes adolescentes mexicanos mestizos con una muestra de pacientes caucásicos tratados en el estudio a largo plazo de Tweed-Merrifield, ambos con mecánicas de Tweed. Metodología. La muestra consistió de 57 pacientes mexicanos mestizos (35 mujeres y 22 hombres) con una edad promedio de 12.61 años, que presentaban Clase II y Clase I de Angle tratados con mecánica Edgewise estándar por un especialista (M.G.P.G.), pareados por edad (± 6 meses), sexo y maloclusión, con 57 pacientes blancos americanos Clase II y Clase I de Angle con una edad promedio de 13.24 años, tomados de la muestra del Estudio a Largo Plazo de la Fundación Charles H. Tweed. Los cefalogramas de ambas muestras fueron trazados, digitalizados y analizados por medio de estudios cefalométricos estadísticos descriptivos. Resultados. Las variables del triángulo de Tweed no presentaron diferencias entre los grupos al principio del tratamiento, mientras que el enderezamiento de los incisivos inferiores dados por los ángulos FMIA e IMPA sí mostraron diferencias estadísticas significativas al final del tratamiento (p > 0.05). Es decir, cuando se compararon los elementos de diagnóstico de pretratamiento y postratamiento entre los mexicanos mestizos y caucásicos, el enderezamiento de los incisivos inferiores en los primeros fue casi el doble de la cantidad de enderezamiento en los segundos caucásicos, FMIA 7.92° versus 3.91°, (p < 0.05); IMPA -6.35° versus -3.66° (p < 0.05). Conclusiones. Los pacientes adolescentes mexicanos fueron tratados para terminar con un perfil más recto registrando una mejora mayor, acorde con el rango normal del objetivo al final del tratamiento dado por Tweed. Ambas muestras, la de mestizos mexicanos y la de caucásicos fueron tratadas para satisfacer los principios enunciados hace mucho tiempo por Tweed: terminar con los incisivos inferiores enderezados sobre el hueso basal para lograr un balance y armonía facial. [ABSTRACT FROM AUTHOR]
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Database:	MedicLatina

Description
Abstract:	Introduction. Dr. Charles Tweed's became world famous with his technique of transforming patients with protrusive faces into patients with pleasing facial contour. He developed the diagnostic facial triangle and stressed the importance of it. Objective. To compare a sample of Mexican Mestizo adolescents treated in México and a Caucasian adolescent sample from The Tweed-Merrifield Long-Term Study, both treated with the same Tweed mechanics. Methodology. The sample consisted in a total of 57 Mexican Mestizo patients, 35 girls and 22 boys with a mean age of 12.61 years, Angle Class I and Class II treated with standard Edgewise mechanics by a specialist (M.G.P.G.). Records of these patients were matched by age (± 6 months) sex, malocclusion and were compared to 57 American whites with a mean age of 13.24 years Class I and Class II patients treated with standard Edgewise mechanics from the Charles H. Tweed Foundation Long Term Study. The cephalograms of the two samples were traced, digitized, and analyzed by descriptive cephalometric analysis. Results. Tweed Triangle variables were not different between the groups at the start of treatment, whereas uprighting of the lower incisor FMIA and IMPA angles were statistically significant at the end of treatment (p < 0.05). Conversely, when comparing the start and finish records between Mexican Mestizo and Caucasians, lower incisors uprighting in the former was almost twice the amount of the latter, Caucasians FMIA 7.92° versus 3.91°, (p < 0.05); IMPA-6.35° versus -3.66° (p < 0.05). Conclusions. Mexican Mestizos were treated to a straighter profile to render a greater improvement, but well into Tweed's normal range at the completion of treatment. Both the Mexican Mestizo and Caucasian samples were treated according to the same principles enunciated by Tweed many years ago: the lower incisors were uprighted over the basal bone in order to achieve facial balance and harmony. [ABSTRACT FROM AUTHOR]
ISSN:	1665143X