TREATMENT CLASSIFICATION OF CLASS III MALOCCLUSION Clinical and Cephalometric Morphologic Features Table 2 COMPONENTS DENTOALVEOLAR SKELETAL CATEGORY 1. Class III Type 1 (pseudo Class III or Dewey Anderson Class I Type 3) 2. Class III Type 2 (Dentoalveolar III) 2a. Dental closed bite 2b. Dental open bite 3. Class III Type 3 (Retrognathic Maxil-lary Class III) 3a. Skeletal closed bite 3b. Skeletal open bite AGE 6 to adult MOLAR Class I < ¼ cusp mesial INCISOR CROSSBITES Reverse Anterior sometimes posterior WITS 1.0 to -1.0 2.0 to -2.0 2.0 to -2.0 -2.0 to -7.0* -2.0 to -7.0* MAND. PL< <30° FACE Mesocephalic (Meso) Meso to Brachy-cephalic (Brachy) Meso 6 to 14yrs Class III ¼ to ½ cusp mesial Reverse dental deep bite Edge to edge or dental open bite Reverse dental deep bite Edge to edge or dental open bite Anterior sometimes posterior Anterior sometimes posterior Anterior frequently posterior Anterior frequently posterior Anterior frequently posterior Anterior frequently posterior Anterior frequently posterior <30° 6 to 14yrs Class III ¼ to ½ cusp mesial <30° Open bite due to over erupting molars 6 to adult Class III ½ to full Cusp mesial Class III ½ to full Cusp mesial <20° Brachy to Meso 6 to adult >30° Doliocephalic (Dolio) 4. Class III Type 4 (Prognathic Mandibular Class III) 4a. Skeletal closed bite 4b. Skeletal open bite 5. Class III Type 5 (Combination retro Maxillary/prog Mand) 5a. Skeletal closed bite 5b. Skeletal open bite 6 to adult Class III ½ to full Cusp mesial Reverse dental deep bite -2.0 to -7.0* <20° Brachy to Meso 6 to adult Class III ½ to full Cusp Edge to edge or dental open bite Reverse dental deep bite Reverse dental open bite or edge to edge -2.0 to -7.0* -4.0 to -10.0* >30° Dolio 10 to adult Class III full Cusp mesial <20° Brachy to Meso 10 to adult Class III full Cusp mesial Anterior frequently posterior -4.0 to -10.0* >30° Dolio 6. Class III Type 6 (Combination Bi-Maxillary Protrusion/ bi-Maxillary retrusion) 6a. Skeletal closed bite 6b. Skeletal open bite 6 to adult Class III full Cusp mesial Reverse dental deep bite Anterior frequently posterior -2.0 to -7.0* <20° Brachy 6 to adult Class III full Cusp mesial Reverse dental open bite or edge to edge Reverse usually dental open Anterior frequently posterior -2.0 to -7.0* >30° Dolio 7. Class III Type 7 (Craniofacial Syndrome, i.e. Crouzon’s) Infant to adult Class III full Cusp Anterior and/ or posterior -4.0 to -10.0* >30° Dolio *McNamara analysis required to determine both maxillary and mandibular lengths from point A to condylion and gnathion to condylion, respectively, and than compared to age related standards. This analysis is the basis for determining maxil-lary retrognathism or mandibular prognathism. Mandibular plane angle (Mand PL <) measured relative to the MP-FH line. If the MP-SN angle is used, add approximately 7 degrees to the above measures. Reverse incisor relationship represents a negative horizontal overlap of the incisors. www.orthodontics.com March/April 2013 25
Journal of the American Orthodontic Society March-April 2013: Page 25
