Rate Of Tooth Movement Research Articles

The effect of bifidobacterium probiotic on heat shock protein-70 expression and osteoclast number during orthodontic tooth movement in rats (Rattus novergicus)

Heat shock protein (HSP)-70 expressed in the fibroblast of periodontal ligament after orthodontic tooth movement (OTM) was applied. Bifidobacterium probiotics regulate the number of osteoclasts through controlling the inflammation via Nuclear Factor Kappa Beta (NFKB) and increased cytoprotection by HSP induction. This study aimed to examine the effect of Bifidobacterium probiotic on HSP-70 expression and osteoclast number during OTM in the compression side of Wistar rats (Rattus novergicus). This research was a true experimental study which used post-test only group design. 42-healthy-Wistar rats (R. novergicus) were blind randomly divided into 6 groups; K1: OTM for 3 days; K2: OTM for 7 days; K3: OTM for 14 days; KP1: OTM and administration of Bifidobacterium probiotic for 3 days; KP2: OTM and administration of Bifidobacterium probiotic for 7 days; KP3: OTM and administration of Bifidobacterium probiotic for 14 days. OTM model was made by installed closed-coil spring with 10g/mm2 force. Bifidobacterium probiotic was orally administered with 10mL/day by means of oral gavage at 1.5 x 108 CFU/mL dose every day. Immunohistochemical analyses were performed in all study groups. One-way ANOVA and LSD test (p<0.05) were performed to compare between groups. The highest HSP-70 expression was discovered in K3 control group and the greatest osteoclast number was found in KP1 control group. The lowest HSP-70 expression and osteoclast number were found in KP3 group with significant between groups. Bifidobacterium probiotic decreased the expression of HSP-70 and osteoclast number during the orthodontic tooth movement in 14 days in the compression side.

Recombinant human insulin-like growth factor-1 promotes osteoclast formation and accelerates orthodontic tooth movement in rats.

Background: IGF-1 may be an important factor in bone remodeling, but its mechanism of action on osteoclasts during orthodontic tooth movement is complex and unclear. Methodology: The closed-coil spring was placed between the left maxillary first molar and upper incisors with a force of 50 g to establish an orthodontic movement model. Eighty SD rats were randomized to receive phosphate buffer saline or 400 ng rhIGF-1 in the lateral buccal mucosa of the left maxillary first molar every two days. Tissue sections were stained for tartrate-resistant acidic phosphatase (TRAP), the number of TRAP-positive cells was estimated and tooth movement measured. Results: The rhIGF-1 group exhibited evidential bone resorption and lacuna appeared on the alveolar bone compared to the control group. Moreover, the number of osteoclasts in compression side of the periodontal ligament in the rhIGF-1 group peaked at day 4 (11.37±0.95 compared to 5.28±0.47 in the control group) after the orthodontic force was applied and was significantly higher than that of the control group (p<0.01). Furthermore, the distance of tooth movement in the rhIGF-1 group was significantly larger than that of the control group from day 4 to day 14 (p<0.01), suggesting that rhIGF-1 accelerated orthodontic tooth movement. Conclusion: Our study has showed that rhIGF-1 could stimulate the formation of osteoclasts in the periodontal ligament, and accelerate bone remodeling and orthodontic tooth movement.

Comparison of tooth movement and biological response resulting from different force magnitudes combined with osteoperforation in rabbits.

To compare tooth movement rate and histological responses with three different force magnitude designs under osteoperforation in rabbit models. 48 rabbits were divided into three groups: Group A, Group B, and Group C, with traction force of 50 g, 100 g, 150 g, respectively. Osteoperforation was performed at the mesial of the right mandibular first premolar, the left side was not affected. One mini-screw was inserted into bones between two central incisors. Coil springs were fixed to the first premolars and the mini-screw. Tooth movement distance was calculated, and immunohistochemical staining of PCNA, OCN, VEGF, and TGF-β1 was analyzed. The tooth movement distance on the surgical side was larger than the control side in all groups (P<0.01). No significant intergroup difference was observed for the surgical side in tooth movement distance among the three groups (P>0.05). For the control side, tooth movement distance in Group A was significantly smaller than Groups B and C (P<0.001); no significant difference in tooth movement distance between Group B and Group C was observed (P>0.05). On the tension area of the moving premolar, labeling of PCNA, OCN, VEGF and TGF-β1 were confirmed in alveolar bone and periodontal ligament in all groups. PCNA, OCN, VEGF and TGF-β1 on the surgical side was larger than the control side in all groups (P<0.001). Osteoperforation could accelerate orthodontic tooth movement rate in rabbits. Fast osteoperforation-assisted tooth movement in rabbits was achieve with light 50 g traction.

Adverse effect of consumption of carbonated soft drinks on orthodontic treatment - A systematic review.

The complications of soft drink consumption during orthodontic treatment includes degradation of enamel, reduction in the shear bond strength of orthodontic brackets, and also corrosion of orthodontic wires. The main objective of this review is to discuss the adverse effects of carbonated soft drink (CSD) consumption on patients undergoing fixed orthodontic treatment. A search of studies in MEDLINE (via PubMed), the Cochrane library, Web of science, IndMED, EMBASE, Google scholar and limited grey literature on the effects of consumption of CSDs was conducted. All pertinent abstracts were reviewed for inclusion. Full articles were retrieved for abstracts or titles that met the initial inclusion criteria or lacked sufficient detail for immediate exclusion. Out of the 4484 results obtained from search, 16 articles were selected based on title and 6 articles were eliminated after reading the abstracts. 10 articles were selected for systematic review which included 6 invitro studies, 1 animal study, 1 observational study and 2 invivo studies. Of these, six studies evaluated the effects of carbonated drinks on the shear bond strength of brackets on enamel of which two evaluated the microhardness of enamel, two studies evaluated the mechanical and chemical properties of wires, one evaluated tooth movement and one study focussed on white spot lesions. The results from the selected articles showed that with the consumption of carbonated drinks, there was reduced shear bond strength of orthodontic brackets, altered enamel characteristics, alteration of mechanical and physical properties of orthodontic wires and decrease in rate of orthodontic tooth movement. Based on the available evidence, CSD consumption during orthodontic treatment definitely has an effect on orthodontic appliances, enamel and possibly on tooth movement.

Pulpal blood flow changes and pain scores related to using Superelastic 0.018-inch Nickel Titanium as the first orthodontic alignment archwire: a prospective clinical trial.

Background Optimal orthodontic force results in maximum rate of tooth movement without tissue damage. Even though starting orthodontic treatment with a thicker archwire may shorten treatment duration, the evidence on the effect of using 0.018-inch NiTi as the first alignment archwire on pulpal blood flow (PBF) status is still scarce.Objectives to record PBF changes and pain scores associated with using 0.018-inch NiTi as the first alignment archwire during fixed orthodontic treatment.Methodology Patients were selected from subjects attending postgraduate orthodontic teaching clinics at Jordan University of Science and Technology. In total, forty healthy patients who exhibited mild lower arch crowding were included. A split-mouth trial design was used. Each patient received two archwire sizes at one time joined in the midline by crimpable hook and applied in the lower arch. Patients were assigned into one of two groups based on archwire sizes used. Group 1: 0.014-inch and 0.018-inch NiTi (Six males, 14 females aged 19.4±1.33 years) and Group 2: 0.016-inch and 0.018-inch NiTi (Seven males, 13 females aged 19.6±1.45 years). The archwire size group was randomly allocated with a 1:1 allocation ratio. A Laser Doppler Flowmeter was used to measure PBF at different time intervals (T0-T5). Pain scores were recorded using a visual analogue scale (VAS). A repeated measures ANOVA and a post-hoc Bonferroni comparison tests were conducted to examine differences at the different time points before and during orthodontic alignment.Results For all studied archwire sizes, PBF decreased 20 minutes after their placement. Most PBF changes occurred within 24hours and continued to decrease until 72 hours after archwire placement where the maximum reduction was reached. Eventually, normal values were reverted within 1 month. PBF changes were similar between all alignment – groups.Conclusions Initial orthodontic alignment with 0.018-inch NiTi does not cause irreversible changes to pulpal vasculature or produces higher pain scores.

Radiographic and histochemical assessment of root resorption during canine retraction through piezocision site.

The number of adult patients seeking orthodontics treatment has increased drastically. There is increased need for faster tooth movement and good esthetics. Piezocision is one of the methods used for accelerating the rate of tooth movement. To assess the amount of root resorption after retraction of canine through piezocision site and compare it with that of recently extracted site using cone-beam computed tomography (CBCT) and assessment of dentin sialoprotein (DSP) levels in gingival crevicular fluid (GCF). A split mouth design was used in 15 patients who were undergoing first orthodontic treatment with premolar extractions. Randomly one of the sides was chosen as control (Group I) and the other side underwent piezocision procedure (Group II). 0.022 × 0.028'' MBT system was used with 0.017 × 0.025 SS wire for canine retraction using 150 grams of force. GCF samples were collected from mesio-buccal and disto-buccal of the canine with micropipette at baseline (TO) and day 90(T1) to detect the levels of DSP and the root resorption was measured using CBCT. Statistically significant amount of root resorption was observed after retraction in both the groups. DSP levels were increased in both the groups, though little higher in Group II when compared to group I. DSP level was increased on the piezocision side but it was statistically insignificant which suggests the amount of root resorption on both the sides is similar.

The Effect of Stem Cells on the Rate of Canine Retraction

Purpose: This study was done to evaluate the effect of mandibular stem cells (MMSCs) on the rate of canine retraction. Materials and methods: The participants were twelve female patients with a bimaxillary dentoalveolar protrusion and age range from 15-21 (mean±SD 18.2 ±1.7). Bone marrow stem cells (BMSCs) were injected to one side, either right or left, while the other side served as a control group. Both upper and lower canines were retracted. Canines retraction were done under 150 gm of force using a 9 mm nickel-titanium TAD closed-coil spring between miniscrew and power arm welded to canines’ bracket. Alginate impressions were taken every month until all canines had reached the second premolars, and study casts were fabricated and then scanned with a 3D scanner. Results: stem cells significantly increased the rate of tooth movement, particularly at T1. Anchorage loss was negligible and insignificant between the two groups. The pain was lower in the stem cells group, and patients were almost satisfied with the procedure. Conclusion: Non-cultured stem cell injection is a safe procedure that could be an effective method to accelerate tooth movement andsignificantly reduce the duration of orthodontic treatment.

Miniscrew Implant supported Maxillary Canine Retraction with and without Corticotomy Facilitated Orthodontics (CFO).

Introduction:The purpose of the study was to scientifically test maxillary canine retraction assisted by miniscrew implant with corticotomy-facilitated orthodontics.Materials and Methods:Fifteen patients (six males, nine females) who had Class II division malocclusion with enhanced overjet were included in the study. Maxillary first premolars were surgical displaced along with retraction of maxillary. In the canine-premolar region, corticotomy was performed on one side of the maxillary arch; the other side served as the control region. Over a 4-month follow-up span, the following variables were examined: plaque index, tooth movement intensity, attachment degree, gingival regression, molar anchorage failure, gingival index, and scope of testing.Results:After 2 months, the canine retraction rate on the corticotomy side was more significant than on the control side by twice. The tooth movement rate steadily decreased to 1.6 times faster at the end of the 3rd month and to 1.06 times faster at the end of the 4th month. No failure of molar anchorage occurred on either the controlled or nonoperated hand during canine retraction.Conclusions:For people requiring orthodontic care with shortened treatment periods, corticotomy-facilitated orthodontics may be a viable treatment modality.

Effect of isotretinoin on induced tooth movement in rats

This study was performed to evaluate the effect of isotretinoin on tooth displacement and tissues related to induced tooth movement (ITM) in rats. Wistar rats were randomly divided into 4 groups: vegetable oil (O; n=40), 7.5mg/kg isotretinoin (I; n=40), vegetable oil+ITM (OM; n=44), and 7.5mg/kg isotretinoin and ITM (IM; n=39). After the daily application of the solutions for 30days, an orthodontic appliance was installed to mesially displace the maxillary first right molar (30cN) of rats in the OM and IM groups. The animals were killed 2, 7, 14, or 21days after placement of the devices. The animals in the O and I groups did not undergo ITM but were killed simultaneously. The animals were examined for tooth displacement, the neoformation of mature collagen, bone and root resorption, the presence of hyalinized areas, and trabecular bone modeling by microcomputed tomography. There was no difference in tooth displacement, the number of osteoclasts, the presence of hyalinized areas, or trabecular bone among the O, I, OM, and IM groups across the periods tested (P>0.05). A lower percentage of mature collagen was found in the IM group than in the OM group on day 7 (P<0.05). A lower frequency of root resorption was found in the IM group than in the OM group on days 2 and 21 (P<0.05). Isotretinoin at 7.5mg/kg decreased root resorption in rats subjected to ITM.

Smoking cessation rescues tooth movement delays caused by tobacco smoke components

ABSTRACT Purpose: Smokers who receive orthodontic treatment occasionally require longer treatment periods. Nevertheless, it is unclear whether delayed tooth movement can be recovered by encouraging smoking cessation. The study was designed to examine whether tooth movement rates can be recovered by a period of smoking cessation in rats treated with a comprehensive mixture of tobacco smoke components (TSCs). Materials and methods: Nine-week-old Wistar male rats were divided into no treatment, sham, TSCs, and TSCs cessation groups. The rats in the no treatment and sham groups drank distilled water, whereas those in the TSCs group and the TSCs cessation groups received TSCs in their drinking water. A smoking cessation period of 10 days was set for rats in the TSCs cessation group before the three groups underwent tooth movement. Tooth movement distance was measured using micro-computed tomography, and osteoclast differentiation was evaluated histologically. Results: There was significantly greater tooth movement in the sham and TSCs cessation groups than in the TSCs group. However, the TSCs cessation group showed lesser osteoclast differentiation than the sham group. Conclusion: Our results indicate that delayed tooth movement caused by smoking was recovered by smoking cessation treatment; this recovery seems to be partially due to the increase in osteoclasts, although the number of osteoclasts was still less than that in the sham group.

Local Vascularization during Orthodontic Tooth Movement in a Split Mouth Rat Model-A MRI Study.

Orthodontic tooth movement to therapeutically align malpositioned teeth is supposed to impact blood flow in the surrounding tissues. Here, we evaluated actual vascularization in the tension area of the periodontal ligament during experimental tooth movement in rats (N = 8) with magnetic resonance imaging (MRI). We inserted an elastic band between the left upper first and the second rat molar; the right side was not treated and served as control. After four days of tooth movement, we recorded T1-weighted morphologic and dynamic-contrast-enhanced MRI sequences with an animal-specific 7 Tesla MRI to assess of local vascularization. Furthermore, we quantified osteoclasts and monocytes in the periodontal ligament, which are crucial for orthodontic tooth movement, root resorptions as undesirable side effects, as well as the extent of tooth movement using paraffine histology and micro-CT analysis. Data were tested for normal distribution with Shapiro–Wilk tests followed by either a two-tailed paired t-test or a Wilcoxon matched-pairs signed rank test. Significant orthodontic tooth movement was induced within the four days of treatment, as evidenced by increased osteoclast and monocyte activity in the periodontal ligament as well as by µCT analysis. Contrast enhancement was increased at the orthodontically-treated side distally of the moved upper first left molar, indicating increased vascularization at the tension side of the periodontal ligament. Accordingly, we detected reduced time-to-peak and washout rates. Our study using MRI to directly assess local vascularization thus seems to confirm the hypothesis that perfusion is enhanced in tension zones of the periodontal ligament during orthodontic tooth movement.

Effects of 405-, 532-, 650-, and 940-nm wavelengths of low-level laser therapies on orthodontic tooth movement in rats

BackgroundInvestigating the effects of 405-nm, 532-nm, 650-nm, and 950-nm wavelengths of LLLTs (low-level laser therapies) on the orthodontic tooth movement in rats by using histological and immunohistochemical methods. Forty-five Wistar albino rats were randomly divided into 5 groups: control group (positive control: the left maxillary 1st molar side; negative control: the right maxillary 1st molar side), 405 nm LLLT group (Realpoo), 532 nm LLLT group (Realpoo), 650 nm LLLT group (Realpoo), and 940 nm LLLT group (Biolase). The left maxillary 1st molar teeth of all rats were applied mesially 50-g force. Starting from the 1st day, 48 h intervals, LLLT was applied in continuous wave mode and in contact with the tissue. The application area was approximately 1 cm2. The lasers were performed for 3 min on each surface (buccal, palatal, mesial), totally 9 min (total dose 54 J/cm2). The amount of the molar mesialization, the bone area between the roots, PDL (periodontal ligament) measurements, TRAP (tartrate-resistant acid phosphatase), and ALP (alkaline phosphatase) immunoreactivity intensity were calculated.ResultsThe amount of the molar mesialization was significantly higher in the 650 nm LLLT group (mean 0.878 ± 0.201 mm; 95% CI (confidence interval) 0.724 and 1.032) than in the groups of positive control (mean 0.467 ± 0.357 mm; 95% CI 0.192 and 0.741) and 405 nm LLLT (mean 0.644 ± 0.261 mm; 95% CI 0.443 and 0.845) (p < 0.001). There were significant differences in the PDL-mesial (p = 0.042) and PDL-distal (p = 0.007) regions between the groups. The immunoreactivity intensity for TRAP-mesial was significantly higher in the positive control group (mean 109,420.33 ± 8769.17; 95% CI 100,217.65 and 118,623.02) than in the 405 nm (mean 91,678.83 ± 7313.39; 95% CI 84,003.9 and 99,353.77) and the 650 nm LLLT (mean 87,169.17 ± 4934.65; 95% CI 81,990.56 and 92,347.77) groups (p = 0.002). There was no statistically significant difference between the groups on immunoreactivity intensity with ALP staining.ConclusionsThe results of this study show that LLLT with 650-nm wavelength increases orthodontic tooth movement more than 405-nm, 532-nm, and 940-nm LLLTs. The 940-nm and 650-nm LLLTs also increase the bone area between the roots by more than 405-nm and 532-nm wavelengths.

Parathyroid hormone increases alveolar bone homoeostasis during orthodontic tooth movement in rats with periodontitis via crosstalk between STAT3 and \u03b2-catenin

Periodontitis patients are at risk of alveolar bone loss during orthodontic treatment. The aim of this study was to investigate whether intermittent parathyroid hormone (1–34) treatment (iPTH) could reduce alveolar bone loss during orthodontic tooth movement (OTM) in individuals with periodontitis and the underlying mechanism. A rat model of OTM in the context of periodontitis was established and alveolar bone loss was observed. The control, iPTH and iPTH + stattic groups received injections of vehicle, PTH and vehicle, or PTH and the signal transducer and activator of transcription 3 (STAT3) inhibitor stattic, respectively. iPTH prevented alveolar bone loss by enhancing osteogenesis and suppressing bone resorption in the alveolar bone during OTM in rats with periodontitis. This effect of iPTH was along with STAT3 activation and reduced by a local injection of stattic. iPTH promoted osteoblastic differentiation and might further regulate the Wnt/β-catenin pathway in a STAT3-dependent manner. The findings of this study suggest that iPTH might reduce alveolar bone loss during OTM in rats with periodontitis through STAT3/β-catenin crosstalk.

Comparison of Rate of Canine Retraction and Secondary Outcomes Associated With Conventional Fixed Orthodontic Treatment and Minimally Invasive Techniques (MOPs): A Randomized Control Trial

Introduction: The objective of the study was to assess the rate of canine retraction and secondary outcomes associated with conventional fixed orthodontic treatment (CFO) and CFO with micro-osteoperforation (CFO + MOP), that is, anchorage loss, root resorption, vitality of tooth, pain and discomfort level during the procedure. Methods: A total of 16 patients with Class II Division 1 malocclusion who required upper first premolar extraction with lower non-extraction/single incisor extraction were divided into the test group (MOP) and positive control group (CFO + MOP) for a split-mouth study. Both maxillary canines were retracted with nickel–titanium (NiTi) closed coil springs. Patients were reviewed after 24 hours, 7 days, 28 days, and 4, 8, and 16 weeks to assess the rate of tooth movement, anchorage loss, root resorption, vitality of tooth, pain and discomfort level. Results: There was a statistically significant difference in the rate of tooth movement between the CFO and CFO + MOP groups after the first 4 weeks ( P-value = .026), whereas no statistically significant difference was observed at 8, 12, and 16 weeks ( P-value = .33, .99, and .08, respectively). In the CFO group, there was no statistically significant difference in tooth movement between different time intervals ( P-value &gt; .05). There was no significant difference in root resorption between the groups. The pain level was higher in the MOP group in the first 24 hours ( P-value &lt; .05) after the procedure. Later on, the difference in pain level between the groups was not significant ( P-value &gt; .05). The vitality of retracted canines in both groups was healthy. Conclusion: The study recommends that the CFO + MOP procedure has substantial potential to be used as an adjunct to the routine mechanotherapy for faster tooth movement, as it may reduce the treatment time by half in the first 4 weeks after the MOP procedure. There are no potential differences in anchorage loss, tipping, vitality, and apical and lateral root resorption between the CFO and CFO + MOP groups. This trial was registered at Clinical Trial Registry, India.

Three-dimensional assessment of accelerating orthodontic tooth movement-micro-osteoperforations vs piezocision: A randomized, parallel-group and split-mouth controlled clinical trial.

To compare the effects of micro-osteoperforations (MOPs) vs piezocision (Piezo) in accelerating orthodontic tooth movement in adults. In this randomized, single-blinded, parallel-group, split-mouth clinical trial, 24 patients aged 15-40years were recruited. Patients were randomly allocated into two groups: MOPs and Piezo groups. One side of the maxilla was allocated randomly for treatment with one of these techniques, and the other side was treated conventionally to act as a split-mouth control. The rate of canine retraction was evaluated up to 3months by three-dimensional digital models using a conventional labial appliance. Root resorption and bone height were evaluated using cone beam computed tomography. The MOPs and Piezo groups showed a significantly higher rate of tooth movement after 3months on the experimental sides than the control sides. However, the net movements in the MOPs and Piezo groups did not reveal a higher rate of tooth movement. Similarly, the overall net movement was -0.32±1.14 and -0.55±0.89mm for MOPs and Piezo, respectively (P=.606). Regarding root resorption, the overall changes in intra- or intergroup comparisons were insignificant. Decreased canine palatal bone height was reported on the experimental side of the Piezo group (P=.015) after 3months, but the overall changes were insignificant. The effect of MOPs and Piezo techniques in accelerating the orthodontic canine retraction was comparable to each other, and to the conventional methods. Neither technique caused root resorption or increased vertical bone loss.

Comparative assessment of the rate of orthodontic tooth movement in adolescent patients undergoing treatment by first bicuspid extraction and en mass retraction, associated with low-frequency mechanical vibrations in passive self-ligating and conventional brackets: A randomized controlled trial

Low-frequency vibrations are one of the many non-surgical modalities aimed at increasing the rate of orthodontic tooth movement. The present trial was conducted to assess the efficacy of low-frequency vibrations in increasing the rate of orthodontic tooth movement in adolescent patients undergoing fixed mechanotherapy with passive self-ligating brackets and conventional brackets. Setting and sample population: department of orthodontics and dentofacial orthopaedics in a nationally accredited dental college. Participants, study design and methods: 65 patients were randomly allocated to three groups. Two experimental groups consisted of passive self-ligating and conventionally ligated appliances received low-frequency vibrations. The control group did not receive any vibrations. Allocation ratio was 1:1:1.32. Eligibility criteria: adolescent patients with sound and healthy dentition, incisor irregularity<5mm. rate of orthodontic tooth movement in mm/month. Randomization and blinding: computer-generated random allocation sequencing was done and data assessor was blinded. the Q-Q plot and Shapiro-Wilks test judged the normality of the data. The parametric test included ANCOVA and post-hoc analysis. No statistically significant enhancement of tooth movement was seen in the experimental groups, when comparison was done with the control group P>0.05. Comparison between the two experimental groups did not reveal any significant difference either. No statistically significant increase of orthodontic tooth movement was seen with low-frequency vibrations and the mode of ligation did not have any effect in increasing the rate of tooth movement either.

Effect of low level laser on osteoclasts and collagen fiber remodeling during the process of tooth retention after tooth movement in rats

Effect of low level laser on osteoclasts and collagen fiber remodeling during the process of tooth retention after tooth movement in rats

Effectiveness of vibrational forces on orthodontic treatment : Arandomized, controlled clinical trial.

AcceleDent® Aura (OrthoAccel® Technologies, Bellaire, TX, USA) is aclassII medical device with U.S. Food and Drug Administration approval that uses SoftPulse Technology™ to increase the speed of tooth movement. The aim of this study was to evaluate the application of vibrational forces on the rate of canine distalization. A total of 20patients (10boys and 10girls) who had classII division 1 malocclusion or severe crowding and indicated first premolar extractions for treatment were included in the study. The patients were divided into two groups: 8 in the control group and 12 in the study group. Three-dimensional digital models were taken just before canine distalization and after space closure using the 3Shape TRIOS® R700 (3Shape Inc., Copenhagen, Denmark) device. Linear measurements between molars and canines were evaluated. The results were assessed with SPSS 23.0 program (IBM, Armonk, NY, USA). One subject was excluded from the study group due to insufficient oral hygiene and poor patient compliance. Tooth movement rates were 1.06 mm/month for mandibular and maxillary canine teeth in the control group. In the study group, tooth movement rates were 1.24 mm/month for maxillary canines and 1.09 mm/month for mandibular canines. These differences were not statistically significant (p > 0.05). AcceleDent® Aura is an easy-to-use device; however, in our study its application did not have any positive effects on canine retraction rates.

Influence of thyroxine supplementation on orthodontically induced tooth movement and/or inflammatory root resorption: A systematic review.

The role of thyroxine administration on orthodontically induced tooth movement and/or inflammatory root resorption remains unclear. The aim was to assess the influence of thyroxine administration on orthodontically induced tooth movement and/or inflammatory root resorption. The study protocol was registered in PROSPERO (CRD42020164151). An electronic search of indexed databases was conducted without time or language restrictions up to and including May 2020. The following eligibility criteria were imposed: (a) original prospective controlled clinical studies and/or experimental studies on animal models; (b) subjects undergoing orthodontic therapy with fixed appliances; (c) presence of a control group [orthodontic tooth movement without thyroxine administration]; and (d) intervention: orthodontic tooth movement with thyroxine administration. Review articles, commentaries, letters to the editor, case reports/series, studies with no control group, cross-sectional studies, retrospective studies and studies where thyroxine was administered along with other interventions such as calcitonin and prostaglandins were excluded. Quality of available evidence and risk of bias within studies were assessed. Any disagreements were resolved via consensus discussions. Based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, 8 animal studies were included. Four studies reported that thyroxine administration increases the rate of orthodontic tooth movement; 3 studies did not show a significant difference. Three studies showed that thyroxine administration decreases orthodontically induced inflammatory root resorption; 2 studies found no significant difference. The risk of bias among studies was high. In conclusion, the influence of thyroxine administration on orthodontic tooth movement and/or orthodontically induced inflammatory root resorption in animal models remains unclear.

3D Analysis of Tooth Movement Using 3D Technology.

3D cone beam imaging (CBCT) has allowed clinicians to better understand the anatomical variations of cranial anatomy. One crucial aspect of this technology plays is the understanding of alveolar bone morphology and remodeling. Variations in cortical bone thickness between individuals have been reported. No published study has analyzed the relationship between cortical bone thickness and rate of tooth movement. The aim of this study is to begin answering the question: is there an association between rate of tooth movement and cortical bone thickness? Twenty-three patients underwent extraction of a single premolar in each of the four quadrants prior to orthodontic therapy. Routine clinical records including 3D CBCT images were acquired of all patients prior to first premolar extractions. Rate of tooth movement in each quadrant for each patient was determined via mesiodistal millimetric measurements obtained by a single calibrated operator. With CBCT images, cortical bone thickness was measured at various levels from the alveolar crest along the long axis of the to-be-extracted first premolars. The association between cortical bone thickness and rate of tooth movement was analyzed. Statistically significant associations were found between rate of tooth movement and cortical bone thickness at levels 2mm, 5mm, and 8mm, apical to the alveolar crest in both the right and left maxillary quadrants (p < 0.05). Statistically significant associations were found between rate of tooth movement and cortical bone thickness at levels 5mm and 8mm apical to the alveolar crest in both mandibular quadrants (p < 0.05). Increased cortical bone thickness was associated with decreased rate of tooth movement. There was no statistically significant association between rate of tooth movement and cortical bone thickness 2mm apical to the alveolar crest of the to-be-extracted first premolars in the mandibular left nor right quadrants (p > 0.05). Results suggest an inverse relationship may exist between cortical bone thickness and rate of tooth movement in both the maxilla and mandible. Cortical bone thickness may have the potential to serve as a predictive tool for rate of orthodontic tooth movement.