IADR Abstract Archives
Human Tooth Movement Velocity Relates to Stress and Activity Index
Objectives: This study investigated how tooth movement velocity relates to applied stress and Interleukin-1β (IL-1 β)/IL-1 Receptor Antagonist (IL-1RA) in gingival crevicular fluid (GCF) in adolescents.
Methods: Subjects whose orthodontic treatment involved maxillary first premolar extractions, consented to participate. Segmental mechanics and calibrated continuous stresses of 4, 13, 26, 52, or 78 kPa were used to retract maxillary canines (MX3). Stress magnitudes were randomly assigned and different on right and left in each subject. Between 9-11 study visits were scheduled over 84 days to collect: GCF from distals of MX3 and a control mandibular canine, and dental models made from impressions at each visit. GCF was analyzed for cytokines via magnetic bead assays. Three-dimensional MX3 movement was measured using dental models from each study visit, reference templates, and a measuring microscope. MX3 movements were plotted versus time and slope of distolateral movement/time determined velocity. Activity Index (AI) = Experimental (IL-1β/IL-1RA)/Control (IL-1β/IL-1RA). General linear modeling tested effects of stress, sex, side, and AI on MX3 velocity (α=0.05).
Results: Fifteen females (aged 13.3±1.5 years) and 13 males (aged 13.7±1.4 years) who showed craniofacial and statural growth during treatment had complete data from 27 and 21 MX3, respectively. Side and sex showed no significant effects on velocity, so data for these variables were grouped. Distolateral movement/time was linear, slopes (velocity) significantly increased (Table) with both stress (p<0.0001) and AI (p=0.044) and showed: Velocity (mm/month) = 11.1+(0.003*stress)+(0.018*AI).
Conclusions: Tooth movement velocity in growing adolescents was positively and significantly related to applied stress and AI.
Methods: Subjects whose orthodontic treatment involved maxillary first premolar extractions, consented to participate. Segmental mechanics and calibrated continuous stresses of 4, 13, 26, 52, or 78 kPa were used to retract maxillary canines (MX3). Stress magnitudes were randomly assigned and different on right and left in each subject. Between 9-11 study visits were scheduled over 84 days to collect: GCF from distals of MX3 and a control mandibular canine, and dental models made from impressions at each visit. GCF was analyzed for cytokines via magnetic bead assays. Three-dimensional MX3 movement was measured using dental models from each study visit, reference templates, and a measuring microscope. MX3 movements were plotted versus time and slope of distolateral movement/time determined velocity. Activity Index (AI) = Experimental (IL-1β/IL-1RA)/Control (IL-1β/IL-1RA). General linear modeling tested effects of stress, sex, side, and AI on MX3 velocity (α=0.05).
Results: Fifteen females (aged 13.3±1.5 years) and 13 males (aged 13.7±1.4 years) who showed craniofacial and statural growth during treatment had complete data from 27 and 21 MX3, respectively. Side and sex showed no significant effects on velocity, so data for these variables were grouped. Distolateral movement/time was linear, slopes (velocity) significantly increased (Table) with both stress (p<0.0001) and AI (p=0.044) and showed: Velocity (mm/month) = 11.1+(0.003*stress)+(0.018*AI).
Conclusions: Tooth movement velocity in growing adolescents was positively and significantly related to applied stress and AI.
