Chairat Charoemratrote

Vibratory stimulation increases interleukin-1 beta secretion during orthodontic tooth movement

OBJECTIVES To investigate the effects of application of vibratory stimuli on interleukin (IL)-1β 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-1β levels were analyzed using an enzyme-linked immunosorbent assay. Canine movement was measured monthly. RESULTS Overall, enhanced IL-1β secretion was observed at the pressure sites of experimental canines compared to control canines (mean, 0.64 ± 0.33 pg/µL vs 0.10 ± 0.11 pg/µL, respectively, P < .001). The accumulative amount of tooth movement was greater for the experimental canine than for the control canine (mean, 2.85 ± 0.17 mm vs 1.77 ± 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-1β in GCF and accelerated orthodontic tooth movement.

Interseptal bone reduction on the rate of maxillary canine retraction.

OBJECTIVE To propose and evaluate a novel surgical approach with minimal trauma, termed interseptal bone reduction, combined with the use of a conventional orthodontic fixed appliance to accelerate canine retraction. MATERIALS AND METHODS A split-mouth design study was conducted in 18 female subjects (mean age, 21.9 years) whose bilateral upper first premolars were extracted and who subsequently received canine distalization. The extraction socket on the experimental side was deepened, and interseptal bone distal to the maxillary canine was reduced in thickness using a surgical bur; conventional extraction was performed on the control side. The canines were then distalized using elastomeric chains on both the labial and palatal sides, with a net force of 150 g. The extent of canine movement and rotation was determined from study models, and the angulation was analyzed based on lateral cephalograms. RESULTS A Wilcoxon signed rank test demonstrated that the extent of canine movement in the mesio-distal direction after 3 months was significantly greater on the experimental side than on the control side (5.4 and 3.4 mm, respectively, P  =  .002). However, there was no statistically significant difference in canine angulation or rotation after 3 months between the experimental and control sides. CONCLUSIONS In combination with the use of conventional orthodontic appliances, interseptal bone reduction can enhance the rate of canine movement when interseptal bone is sufficiently reduced in both thickness and depth following surgical criteria.

Factors related to alveolar bone thickness during upper incisor retraction

OBJECTIVE To investigate the factors related to changes in alveolar bone thickness during upper incisor retraction. MATERIALS AND METHODS The subjects consisted of 23 ongoing orthodontic patients (mean age 20.4 ± 2.7 years) whose upper incisors were bound for retraction. Changes in alveolar bone thickness in the retracted area were assessed using preretraction (T0) and postretraction (T1) cone-beam computed tomography images. Labial bone thickness (LBT), palatal bone thickness (PBT), and total bone thickness (TBT) were assessed at the crestal, midroot, and apical levels of the retracted incisors. Paired t-tests were used to compare T0 and T1 bone thickness measurements. Spearmans rank correlation analysis was performed to determine the relationship of changes in alveolar bone thickness with the rate of tooth movement, change in inclination, initial alveolar bone thickness, and the extent of intrusion. RESULTS As the upper incisors were retracted, the LBT at the crestal level and TBT at the apical level significantly increased (P < .005). Changes in alveolar bone thickness were significantly associated with the rate of tooth movement, change in inclination, and extent of intrusion (P < .05) but not initial alveolar bone thickness (P > .05). CONCLUSION Rate of tooth movement, change in inclination, and extent of intrusion are significant factors that may influence alveolar bone thickness during upper incisor retraction. These factors must be carefully monitored to avoid the undesirable thickening of alveolar bone.

Changes of anterior maxillary alveolar bone thickness following incisor proclination and extrusion

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 0.016″ beta-titanium advancing loops and Class III elastics. Lateral cephalograms were recorded before advancement (T0) and 4 months after a normal overjet and overbite were achieved (T1). 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  =  -0.71; 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.

Effects of Continuous and Interrupted Orthodontic Force on Interleukin-1β and Interleukin-8 Secretion in Human Gingival Crevicular Fluid

The purpose of this study was to compare levels of human IL-1β and IL-8 secretion during tooth movement using a nickel-titanium closed coil spring (NTCS) and an elastic c-chain (EC). Data were obtained from twenty healthy orthodontic patients treated with a pre-adjusted edgewise appliance with all first premolars extracted. In each subject, one maxillary canine received continuous force with a NTCS. The opposite maxillary canine received an interrupted force with an EC. Gingival crevicular fluid (GCF) was collected from distal sides of the canines before bracket placement, before canine retraction (baseline), at 24 hours, and at 1 and 2 months after canine retraction. IL-1β and IL-8 levels were measured. The amount of canine movement was measured from the models using the third palatal rugae as the reference point. IL-1β and IL-8 levels at each time point were compared to the baseline by analysis of variance (ANOVA) for repeated measures. A paired t-test was used to determine any significant differences of IL-1β and IL-8 levels between the groups at each time point and to compare the rate of canine movement between groups. The results demonstrated that IL-1β and IL-8 levels in both groups showed a significant elevation at 24 hours, and then declined. IL-1β and IL-8 levels in the NTCS group were significantly higher than the EC group at 24 hours, and 1 and 2 months after force application (p<0.001). The rate of canine retraction in the NTCS group was significantly higher than that of the EC group (p<0.001). In conclusion, the NTCS gave higher rate of canine retraction, which correlates with IL-1β and IL-8 levels.

Treatment effects of mandibular anterior position training versus a fixed Class II corrector in growing patients with skeletal Class II malocclusion

Abstract Purpose To compare treatment effects of Class II elastics and anterior mandibular position training against fixed Class II corrector (PowerScope™) during the correction of skeletal Class II malocclusion with fixed appliance in growing patients. Materials and methods Thirty-six growing patients with skeletal Class II malocclusion with a retruded pogonion position were randomly allocated to the Class II elastics or PowerScope™ groups. Preadjusted edgewise fixed appliances were used in both treatment groups. Skeletal, dental and profile changes were compared using lateral cephalograms taken before (T0), after initial alignment (T1) and after Class I obtained (T2) for 16/18 patients in the Class II elastics group and 15/18 patients in the PowerScope™ group. Results The duration of treatment was significantly longer for the Class II elastics group than PowerScope™ group. In terms of skeletal changes, Class II elastics increased mandibular length, midfacial length and mandibular plane angle significantly more than the PowerScope™. In terms of dental changes, Class II elastics increased dental height significantly more than the PowerScope™. Conclusions Both treatment modalities reduced severity of Class II malocclusion and decreased profile convexity. Class II elastics with anterior mandibular position training increased mandibular length more but required longer treatment duration. The PowerScope™ had a greater effect on maxillary dento-alveolar restriction. (ClinicalTrials.in.th: TCTR 20180220003).

Comparison of the load-deflection characteristics of 0.012″ heat-activated, superelastic and bent superelastic nickel titanium wires

Abstract Purpose To compare the characteristics and load-deflection graphs of 0.012″ heat-activated NiTi, superelastic NiTi and bent (bends placed at 1, 2 and 3 mm) superelastic NiTi wires, focusing on force at 0.5 mm after deactivation after deflection by 1, 2, 3 and 4 mm. Materials and methods Three-bracket bending tests using a 10 N load cell with 1 mm/min crosshead speed and 8 mm span were performed at 37 °C. Three groups of wires, 0.012″ heat-activated NiTi wires (HANT), superelastic NiTi wires (S), and superelastic NiTi wires with bends placed at 1, 2 and 3 mm (SB1, SB2 and SB3, respectively) were deflected by 1, 2, 3 and 4 mm. Deactivation forces (N) at 0.5 mm after deactivation were compared using ANOVA. Results Bent NiTi wires produced lighter forces than superelastic and heat-activated NiTi wires (P < 0.05). Superelastic and heat-activated NiTi wires had linear load-deflection graphs at 1 mm deflection. No bent NiTi wires had linear load deflection graphs; hysteresis was observed after 2, 3 and 4 mm deflection in all NiTi groups. Increasing the number of bends and deflection appeared to inactivate NiTi wires. Conclusions After any deflection, all bent NiTi wires produce lighter forces at 0.5 mm after deactivation than superelastic NiTi and heat-activated NiTi wires. This study indicates bending a NiTi wire close to a displaced tooth with up to 1 mm deflection can produce an active light deactivation force to level severely displaced teeth.

Volumetric evaluation of root resorption on the upper incisors using cone beam computed tomography after 1 year of orthodontic treatment in adult patients with marginal bone loss

OBJECTIVES: To determine upper incisor root resorption, volume loss, and the relationship between root volume loss and tooth movement after 1 year of orthodontic treatment in patients with marginal bone loss. MATERIALS AND METHODS: A total of 30 women (46.3 ± 5.4 years old) with moderate upper incisor bone loss who required intrusion during orthodontic treatment were recruited. Pre- and post-treatment cone beam computed tomography images were reconstructed. Upper incisors at pre- and post-treatment were superimposed; labio- and palato-apical, middle, and coronal third root volumes were assessed. Tooth movement and alveolar bone height were measured from lateral cephalometric radiographs and cone beam computed tomography. Changes in root volume/alveolar bone height were compared using paired-sample t-tests, percentage root volume loss for each tooth/segment was evaluated by one-way analysis of variance, and the relationship between percentage root loss and degree of tooth movement was assessed by linear regression. RESULTS: Mean root volume significantly decreased on the labio- and palato-apical aspects of 12 and labio-apical aspects of 21 and 22 ( P ≤ .024). Palato-apical segment volume loss was greater on lateral than central incisors ( P ≤ .016). Two-dimensional root length and cementoenamel junction-bone crest distance did not change between T0 and T1, with no significant relationship between tooth movement amount and percentage root volume loss. CONCLUSIONS: Delivery of 40 g intrusive force to the four upper incisors using a T-loop and the leveling phase lead to more apical root volume loss on lateral than central incisors. There was no relationship between extent of tooth movement and upper incisor root volume loss.

Tooth and bone changes after initial anterior dental alignment using preformed vs customized nickel titanium archwires in adults: A randomized clinical trial

OBJECTIVES To compare tooth movement achieved, time required for alignment, root resorption, and alveolar bone thickness changes during initial dental alignment between groups treated with 0.012-inch preformed heat-activated or customized nickel titanium (NiTi) archwires. MATERIALS AND METHODS Thirty-two subjects (mean age 19.8 ± 1.7 years) with severe crowding of maxillary anterior teeth had premolar extractions and were randomly allocated into control and experimental groups receiving preformed heat-activated and customized NiTi archwires, respectively. Limited field of view cone-beam computed tomographies were taken initially (T0) and three months after final alignment (TF) to evaluate bone changes. Digital model analysis assessed tooth movement at monthly intervals. Time to achieve alignment was assessed in months. Wilcoxon signed-rank tests and Mann-Whitney U-tests were used to compare changes within and between groups, as appropriate. RESULTS Central incisor tooth movement was significantly different (all P ≤ .003) between groups at all time points. TF-T0 showed labial movement (0.75 ± 1.42 mm) in the control group and palatal movement (-0.96 ± 0.41 mm) in the experimental group. The experimental compared to control group showed significantly more canine distal movement (0.60 ± 0.28 mm; P ≤ .049), less labial bone thickness changes ( P ≤ .004), less root resorption of the central and lateral incisors ( P ≤ .007), and a longer time to achieve alignment ( P = .01). CONCLUSIONS The experimental group exhibited palatal movement of the central incisors, more canine distal movement with less bone thickness changes, and less root resorption but took more time to achieve alignment than the control group.

Effect of incisal loading during orthodontic treatment in adults: A randomized control trial

OBJECTIVE To measure the changes in tooth mobility, alveolar bone, and receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) in the gingival crevicular fluid (GCF) during orthodontic treatment to regain incisal function in the presence and absence of biting exercises. MATERIALS AND METHODS Thirty-six females (42.3 ± 6.5 years old) with periodontally compromised upper incisors received orthodontic treatment to obtain ideal incisor relationships. Eighteen subjects in the experimental biting exercise group were instructed to bite a soft plastic roll for 5 min/d; the 18 control subjects were not given plastic rolls. Alveolar bone thickness, height, and density around the upper incisors were assessed at three root levels using cone-beam computed tomography. GCF was collected at the labial and palatal sites of the upper incisors at pretreatment (T0), end of treatment (T1), 1 month after T1 (T2), and 7 months after T1 (T3). RANKL/OPG was determined using enzyme-linked immunosorbent assays. RESULTS Labial and palatal bone thickness significantly increased (>twofold) from T1 to T3 in the experimental group at all three root levels (all P < .05). Bone thickness correlated negatively with RANKL/OPG ratio between T1 and T2 ( P < .05). Tooth mobility, bone height, and density were not significantly different between T1 and T3. CONCLUSIONS Biting exercises significantly increased bone thickness but did not affect tooth mobility, bone height, or density. The RANKL/OPG ratio decreased 1 month after treatment (T2) and correlated with increased bone thickness. ( ClinicalTrials.in.th TCTR20170625001).