Class II subdivision malocclusions treated non extraction with symmetrical forces.

University of Minnesota M.S. thesis. July 2012. Major: Dentistry. Advisor: Brent Larson. 1 computer file (PDF); vi, 47 pages.Non-extraction treatment of Class II subdivision malocclusion, with symmetrical forces has not been described in the literature. This study evaluated the use of symmetrical forces with face-bow therapy in conjunction with full fixed appliances of 47 patients (28 females and 19 males) that were treated by the same practitioner. The pretreatment and post-treatment records were taken at an average age of 12.3 and 14.4 years respectively. The results showed that the Caballero index (The distance from the tip of the mesio-buccal cusp of the upper first molar to the mesio-buccal groove of the lower first molar on the class II side.) decreased from 1.86 to 0.12 mm, making this statistically significant. The midline showed a distinctive improvement having a pretreatment value of 1.33 mm and a post treatment value of 0.29 mm. Arch length had a modest gain of 1.15 mm with the left side having the biggest contribution. The maxillary intermolar position remained stable with a 0.3 mm net change. The ANB angle decreased from 3.5 to 2.1 degrees. The upper incisor in relation to S-N and lower incisor inclination increased by 3.3 degrees. Finally, the mandibular plane angle increased in value from 31.2 degrees to 32.2 post treatment. Within the limits of this study and based on the test of equivalence, it is concluded that when symmetrical forces are used in non extraction therapy for Class II subdivision growing patients, the class II malocclusion is corrected, but some asymmetry in the molar position remains