Twin block appliance in different daily wearing times: Comparison of dentofacial effects

The aim of this project was to compare the dentofacial effects of using Twin Block appliance on patients who have Class II Division 1 malocclusion at pubertal growth spurt, with different daily wearing times that was measured objectively via TheraMon microsensor. The 23 patients (14 female, 9 male, avarage age 12.2 ± 1.28 years) who have Class II Division 1 malocclusion at the pubertal growth spurt, have used TheraMon microsensor embedded Twin Block appliances for 10 months (313 ± 14 day). At the end of this period the patients were divided into two groups according to their average daily wearing time. The 11 patients (6 female,5 male, avarage age 12.32 ± 1.25 years) in Group 1 have used their appliances with 18.11 ± 1,51 hours/day; the 12 patients (8 female, 54 male, avarage age 12.07 ± 1.4 years) in the Group 2 have used their appliances with 21.08 ± 0,64 hours/day. The data was obtained by comparing the lateral cephalometric films taken at the beginning of the treatment (T0) and 1 month after the Twin Block appliance was removed (T1). Normally distrubuted measurements were statistically evaluated by Paired-t test and Student-t test; non-normally distributed ones were statistically evaluated by Wilcoxon Signed-Ranks test and Mann Whitney U test. Co-Pog (GR1: 5.01, GR2: 5.38 mm) and Ar-Pog (GR1: 5.47 mm, GR2: 5.72 mm) measurements were increased in a statistically significant level. It was observed that maxillary growth is restricted. Skeletal and dentoalveolar changes contributed almost equally to overjet and molar corrections. Despite observation showed that differences in the Group 2 were numerically higher than Group 1; in the comparison between groups; the statistically significant difference was occurred only in labiomental soft tissue measurement (distance between B-SLi points) (GR1: 0.8 mm, GR2: 1.8 mm, p=0.01). Twin Block appliance was effective in the treatment of Class II malocclusion and there was no difference in wearing protocols of 18 hours/day and 21 hours/day. Key words: Twin Block Appliance, TheraMon Microsensor, Cooperation