Cephalometric Roentgenographic Comparative Study between the Maxillo-Mandibular Ratio (MMR) and McNamara Jr.’s Analysis, in Patients with Normal Occlusion and Angle Malocclusion Class I; Class II, Div. 1; Class II, Div. 2 and Class III

André Luis Ribeiro de MIRANDA, Marco Antonio SCANAVINI

The objective of this study was to compare the maxillo-mandible morphological relationship by means of the Maxillo-Mandibular Ratio (MMR) observed in pacients with class I; class II, div. 1; class II, div. 2 and class III ANGLE malocclusions and normal occlusion and compare this analysis with McNamara Jr.’s analysis. The sample was composed of 200 lateral cephalometric radiographs, obtained from 13-16 years old Brazilians, with no previous orthodontic treatment and no extraction of permanent teeth. The MMR was obtained dividing the length of the maxilla (ENA-ENP) by the length of the mandible (ArGo-GoE) and multiplying by a hundred. These values were compared with those of the McNamara Jr.’s analysis (Co-A and Co-Gn). The results showed correlation between the two variables for the length of the maxilla (ENAENP and Co-A) and between the two variables for the length of the mandible (ArGo-GoE and Co-Gn). The MMR presented the following mean value varying between 40,47% to 41,78% for increased relationship, 41,79% to 43,76% for proportional relationship, and 43,77% to 45,89% for decreased relationship.

Keywords: Cephalometric. MaxilloMandibular Relationship. Normal Occlusion and Malocclusions.

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