The anterior lower facial height in the Class II division 1 with mandibular deficiency

Leopoldino CAPELOZZA FILHO, Sérgio Luiz Menezes Coelho de SOUZA, Arlete de Oliveira CAVASSAN, Terumi Okada OZAWA

Controversies between the cephalometrics analysis of the ALFH (anterior lower facial height) and the clinical diagnosis based on the facial examination on Class II with mandibular deficiency has motivated this article. A sample composed of 26 Class II division 1 with mandibular deficiency individuals without distinction of gender or age already treated were selectedThis sample were characterized with a whole of classical cephalometrics measurements (SNA, SNB, ANB, NAP, ALFH, SNOP, SNGoGn, CoA, CoGn) and a new alternative way of measuring the ALFH were tested. The anterior nasal spine (ANS) and menton (Me) points were projected perpendicularly to a frontal plane that goes through nasion, perpendicular to Frankfourt plane (NperpA, McNamara 1984) and the distance between them measured in a lineal way. The results were compared with the obtained values from ALFH measurements as dictated by McNamara, 1984. We found a reverse relationship between the different measurements (conventional ALFH and ALFH perpendicular). This reverse relationship were statistically significant to whole sample and showed a high correlation. The ALFH perpendicular was always minor than conventional ALFH and exhibited a tendency to be even minor, as higher as were the value obtained to SNGoGn angle. These findings leaded to believe that the ALFH perpendicular, used as preconized in this article, turns the McNamara triangle more balanced and consequently its obtained diagnostic in more concordance with the orthodontic therapy adopted to correct the Class II division 1 with mandibular deficiency.

Keywords: Malocclusion. Class II. Cephalometry.

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