Objectives: To investigate the effects of application of vibratory stimuli on interleukin (IL)-1b secretion during maxillary canine distalization. Materials and Methods: Split-mouth design study in 15 subjects (mean age, 22.9 years; range 19-25 years) whose bilateral maxillary first premolars were extracted with subsequent canine distalization. On the experimental side, light force (60 g) was applied to the canine for 3 months in combination with vibratory stimuli provided using an electric toothbrush 15 minutes a day for 2 months; only orthodontic force was applied to the contralateral control canine. Gingival crevicular fluid (GCF) was collected from the mesial and distal sides of each canine at each monthly appointment. IL-1b levels were analyzed using an enzyme-linked immunosorbent assay. Canine movement was measured monthly. Results: Overall, enhanced IL-1b secretion was observed at the pressure sites of experimental canines compared to control canines (mean, 0.64 6 0.33 pg/mL vs 0.10 6 0.11 pg/mL, respectively, P , .001). The accumulative amount of tooth movement was greater for the experimental canine than for the control canine (mean, 2.85 6 0.17 mm vs 1.77 6 0.11 mm, respectively, P , .001).Conclusions: This study demonstrates that, in combination with light orthodontic force, application of vibratory stimuli using an electric toothbrush enhanced the secretion of IL-1b in GCF and accelerated orthodontic tooth movement. (Angle Orthod. 2016;86:74-80.)

Objective: To investigate changes in maxillary alveolar bone thickness after maxillary incisor proclination and extrusion during anterior crossbite correction in a group of growing patients with Class III malocclusion. Materials and Methods: Maxillary incisors of 15 growing patients with anterior crossbite were proclined and extruded with 0.0160 beta-titanium advancing loops and Class III elastics. Lateral cephalograms were recorded before advancement (T 0 ) and 4 months after a normal overjet and overbite were achieved (T 1 ). Changes in alveolar bone thickness surrounding the maxillary incisors at the crestal (S1), midroot (S2), and apical (S3) levels were measured using cone-beam computed tomography (CBCT). Paired t-tests were used to determine the significance of the changes. A Spearman rank correlation analysis was performed to explore the relationship between thickness changes and the rate and amount of incisor movements. Results: Although statistically significant decreases were observed in palatal and total bone thickness at the S2 and S3 level (P , .05), the amounts of these changes were clinically insignificant, ranging from 0.34 to 0.59 mm. Changes in labial bone thickness at all levels were not significant. Changes in palatal bone thickness at S3 were negatively correlated with changes in incisor inclination. (r 5 20.71; P , .05). Conclusion: In a group of growing patients with Class III malocclusion undergoing anterior crossbite correction, controlled tipping mechanics accompanied by extrusive force may produce successful tooth movement with minimal iatrogenic detriment to the alveolar bone. (Angle Orthod. 2015;85:549-554.)

Objectives To evaluate alveolar bone change in relation to root position change after maxillary incisor retraction via cone-beam computed tomography (CBCT) using stable skeletal structures as a reference. Materials and Methods A total of 17 subjects (age 24.7 ± 4.4 years) who required retraction of the maxillary incisors were included. Labial and palatal alveolar bone changes and root change were assessed from preretraction and 3 months postretraction CBCT images. The reference planes were based on stable skeletal structures. The Kruskal-Wallis test and Wilcoxon signed-rank test were used to compare changes within and between groups, as appropriate. Spearman rank correlations were used to identify the parameters that correlated with alveolar bone change. The significance level was set at .05. Results The labial alveolar bone change after maxillary incisor retraction was statistically significant (P < .05), and the bone remodeling/tooth movement (B/T) ratio was 1:1. However, the palatal bone remained unchanged (P > .05). The change in inclination was significantly related to labial alveolar bone change. Conclusions Using stable skeletal structures as a reference, the change in labial alveolar bone followed tooth movement in an almost 1:1 B/T ratio. Palatal alveolar bone did not remodel following maxillary incisor retraction. The change in inclination was associated with alveolar bone change.

Structured Abstract Objectives To investigate the effects of 30 and 60 Hz vibratory stimulus on canine distalization and RANKL and OPG secretion. Setting and Sample Population Sixty patients requiring canine distalization at the Orthodontic Clinic, Prince of Songkla University. Materials and Methods Patients were randomly assigned to 30 Hz vibration (n = 20), 60 Hz vibration (n = 20), or the control group (n = 20). Modified electric toothbrushes were used to apply vibration to the randomly selected canine for 20 min/day by the investigator combined with 60 cN continuous distalization force from day 1 to day 7. RANKL and OPG were analysed before (T1) and 24 hours (T2), 48 hours (T3) and 7 days (T4) after initiation of distalization. From day 8, vibratory devices were used by the subjects at home. Rate of canine distalization (T1 to 3 months after initiation [T5]) was calculated. Kruskal‐Wallis tests were used for multiple comparisons (significance level, 0.05). Results Canine distalization rate was not different between groups (median; 0.82, 0.87, and 0.83 mm/month for 30, 60 Hz, and control group, respectively; P > 0.05). No within‐ or between‐group differences in RANKL and OPG were observed (P > 0.05), except RANKL on the compression side of the control group was significantly higher at T2, T3 and T4 than T1 (P < 0.001). Conclusion In the clinic, 30 and 60 Hz vibratory stimulus have no additive effect on rate of canine distalization rate, RANKL and OPG secretion or RANKL/OPG ratio.

Background: Anterior bite planes are bite-raising appliances used for deep bite correction. However, muscle responses to anterior bite planes of different harnesses may vary. Objectives:To prospectively evaluate masticatory muscle activity, muscle balance and maximum bite force (MBF) responses to anterior bite planes fabricated from acrylic resin (ABP) or bi-laminate thermoplastic (TBP) over 6 months in children with a deep bite.Methods: Sixty-six children were randomly assigned to the ABP, TBP or untreated control groups. Masticatory muscle activity, activity index (AC) and percentage overlapping coefficient (POC) were assessed by surface electromyography; MBF, using a custom-made bite force sensor. Data were collected before, immediately after appliance insertion and after 2 weeks and 1, 3 and 6 months of treatment. Within-and between-group differences were analysed using the one-way ANOVA/Kruskal-Wallis and Mann-Whitney U tests (α = .05); Friedman's tests were used to assess withingroup differences over time (α = .08).Results: At rest, no dependent variables changed throughout the study. At maximum clenching, masticatory muscle activity immediately dropped significantly but returned to baseline values and was equal to the control group at 1-3 months. The ABP group had significantly lower masseter activity and AC than the TBP group after insertion.Neither POC nor MBF were significantly different within or between groups. Conclusion:Masticatory muscle activity reduced after anterior bite plane insertion but returned to baseline after 1-3 months. Masseter activity decreased significantly more in the ABP group than TBP group. Neither appliance significantly affected POC or MBF.