Rate Of Orthodontic Tooth Movement Research Articles

Micro-osteoperforations and Its Effect on the Rate of Tooth Movement: A Systematic Review.

Prolonged orthodontic treatments have inconvenienced patients and clinicians alike. Surgically assisted techniques for accelerating orthodontic tooth movement have shown promising results in the literature over the years. The minimally invasive nature of micro-osteoperforations (MOPs), however, for enhanced orthodontic tooth movement has recently gained momentum, with many clinical trials conducted on both animals and humans. An electronic search was performed to extract papers using PubMed, Google Scholar, Scopus, and Web of Science. The keywords that were used included “MOP,” “accelerating tooth movement,” “orthodontic tooth movement,” and “regional acceleratory phenomenon.” The studies that met our inclusion criteria were extracted and evaluated in this review. MOPs have been proven time and again, in animal and human studies alike, to increase the rate of orthodontic tooth movement. The application of perforations to cortical bone present in the pathway of teeth, which are specifically to be moved creates transient osteopenia. This reduces the density of the cortical bone, hence speeding up the rate of orthodontic tooth movement. Many techniques have been implemented and perfected to enhance orthodontic tooth movement and shorten the treatment time in the literature. MOPs have proven to be a universally applied, nontechnical, repeatable, and minimally invasive method of accelerating tooth movement, with extremely minimal consequences.

Outcome of photodynamic therapy on orthodontic leveling and alignment of mandibular anterior segment: A controlled clinical trial.

Photodynamic therapy (PDT) is a non-invasive approach that has drawn attention to accelerate orthodontic tooth movement (OTM). However, no studies have been published that evaluates the outcome of PDT on orthodontic leveling and alignment. Therefore, the present study aimed to evaluate outcome of PDT on orthodontic leveling and alignment of mandibular anterior segment. Thirty patients (18 females and 12 males) were included who had moderate mandibular crowding with average age was 19.23 ± 3.1 years. They were randomly divided into a control group without PDT intervention and a laser group. All patients followed non-extraction approach using one category of fixed appliance and matching NiTi archwire sequence for 3 months. In PDT group, methylene blue mediated gallium aluminum arsenide laser was applied with 635 nm, 6.5 J/cm2, for 10 s at 10 points (0.2 J/point) started immediately after first wire then at days 3,7,14 of first month and repeated for additional 2 months. Relief of crowding was assessed by Little`s irregularity index (LII) scores after 4, 8, and 12 weeks through scanned 3-dimensional models via a software. Both groups showed improvements in mandibular crowding as evidenced by significant decreases (p ≤ 0.001) in LII scores during all observation intervals with no significant differences (p > 0.05). Moreover, the alignment`s rate showed no significant differences between groups. PDT produced a negligible effect concerning alignment of crowded mandibular anterior teeth. Besides, OTM's rate at different observation intervals showed an equivalent pattern either with or without PDT.

Combined Effect of Nicotine and Caffeine on Orthodontic Tooth Movement in Rats

Background: The individual effects of nicotine and caffeine have been reported in previous studies but their combined effect on tooth movement needs to be elucidated. The objective of this study was to evaluate the combined effect of nicotine and caffeine on the magnitude of orthodontic tooth movement (OTM) in rats.
 Material and Methods: This experimental study was conducted on Sprague-Dawley rats (Animal House and Pathology Laboratory; Post Graduate Medical Institute, Lahore) in the department of Orthodontics, de’Montmorency College of Dentistry, Lahore from 8th July 2014 to 8th January 2015. Forty male Sprague-Dawley rats were divided into four equal groups: Control group (CR), nicotine group (NT), caffeine group (CF) and combined nicotine and caffeine group (CNC). Closed coil nickel titanium (NiTi) spring was placed between incisor and maxillary molar. Nicotine group (NT) was treated by intraperitoneal injections of nicotine. Caffeine was given to caffeine group and Combined nicotine and caffeine group (CNC) was treated in the same way as individual nicotine and caffeine groups daily for 14 days. All the rats were sacrificed on 15th day. Magnitude of the orthodontic tooth movement was measured using digital Vernier caliper. Means and standard deviation were calculated for orthodontic tooth movement. One-way ANOVA was used to determine the mean difference in OTM. Post hoc Tukey test was used for multiple comparisons among the groups.
 Results: The mean orthodontic tooth movement (OTM) was 0.32 mm ± 0.05 in control group, 0.56 mm ± 0.04 in nicotine group, 0.52 mm ± 0.034 in caffeine group and 0.8 mm ± 0.06 in combined NC group, respectively. The difference between mean OTM among the groups was statistically significant (P-value <0.001). The mean OTM in CNC group was significantly higher as compared to other groups (CR, NT, CF, NT) (P-value <0.001).
 Conclusions: In rats, the combined use of nicotine and caffeine results in greater orthodontic tooth movement as compared to their individual use.

Comparison of rate of orthodontic tooth movement in adolescent patients undergoing treatment by first bicuspid extraction and en-mass retraction, associated with low level laser therapy in passive self-ligating and conventional brackets: A randomized controlled trial

Low Level Laser Therapy (LLLT) is one of the various interventions to accelerate the rate of Orthodontic Tooth Movement (OTM) in adolescent patients who are undergoing en-mass retraction after all first bicuspid extractions. To assess the efficacy of LLLT in increasing the rate of OTM. Setting and sample population: Institutional Department of Orthodontics and Dentofacial Orthopaedics. Participants, study design and methods: 65 Patients requiring all first premolar extractions were randomly allocated to three groups. Two groups (Comprising of passive self-ligating brackets and conventional brackets) were treated with LLLT and one group served as the control (conventional brackets). The allocation ratio was 1:1:1.32. Eligibility criteria: adolescent patients with sound and healthy permanent dentition with Little's Irregularity Index<5mm. rate of tooth movement in mm/month. Randomization and blinding: computer-generated random allocation sequence; only the data analyser was blinded by coding the digital models. Patients were reviewed once every month till the completion of space closure. data normality was checked using Shapiro-Wilks test and Q-Q Plot. Parametric tests were applied for the inferential statistics (ANCOVA) with Dunnett's t test being used for post hoc analysis. There was a statistically significant enhancement in the rate of OTM in the 2 experimental groups (0.68/0.67mm/month in the right and left side of the maxilla and 0.66/0.65mm/month in the right and left side of the mandible) when compared with the control group (0.48mm/month in the maxilla and 0.48mm/month in the mandible) (P<0.05), but when the 2 experimental groups were compared no difference was observed (P>0.05). No serious harms were reported. A significant increase in the rate of OTM was observed with the application of LLLT. No difference was observed in the rate of OTM when comparing different ligation methods treated with LLLT. National Trial Registry (CTRI No- CTRI/2018/04/013156). Protocol was not published before trial commencement.

Botulinum toxin A alleviates orofacial nociception induced by orthodontic tooth movement through nociceptin/orphanin-FQ pathway in rats

ObjectivesTo investigate the effect and mechanism of botulinum neurotoxin type A (BoNT/A) in the modulation of orofacial nociception induced by orthodontic tooth movement in rats. MethodsAn orofacial nociception model was established in male Sprague-Dawley rats by ligating closed-coil springs between incisors and ipsilateral molars. There were two group sets of animals. For the first group set, 120 rats were randomly divided into four groups: no-force group (n = 30), force + saline group (n = 30), force + low dose BoNT/A group (1U/6 μL, n = 30), and force + high dose BoNT/A group (1U/6 μL, n = 30). BoNT/A and saline were injected into periodontal ligament to explore the nociceptive effect of BoNT/A. Ipsilateral trigeminal ganglia (TG) were harvested for detecting the expression levels of nociceptin/orphanin-FQ (N/OFQ). For the second group set, 36 rats were randomly divided into three force groups: BoNT/A + saline group (n = 12), BoNT/A + UFP-101 group (n = 12), and saline + UFP-101 group (n = 12). A potent N/OFQ receptor (NOP) antagonist (UFP-101) was used to examine the role of N/OFQ in BoNT/A-induced antinociception. Tooth-movement nociception level of all groups was evaluated by bite force and rat grimace scale (RGS) at baseline, day 1, day 3, day 5, day 7, day 14. ResultsThe behavioral assessments showed the orofacial nociception level in the force + low dose BoNT/A group and force + high dose BoNT/A group were lower than that in the force + saline group. No significant difference was observed in orofacial nociception among no-force group, force + low dose and force + high dose group. The expression levels of N/OFQ in TG were elevated from day 1 and maintained a high level, presenting in descending order among the force + high dose, force + low dose, force + saline and no-force group, respectively. The nociception level of the BoNT/A + UFP-101 group was higher than that of the BoNT/A + saline group. No significant difference was observed between the BoNT/A + UFP-101 group and the saline + UFP-101 group. ConclusionsBoNT/A can exert an antinociceptive effect on orofacial nociception induced by tooth movement by stimulating the expression of N/OFQ in TG.

BMP2-Functionalized Biomimetic Calcium Phosphate Graft Promotes Alveolar Defect Healing During Orthodontic Tooth Movement in Beagle Dogs.

Background: Grafting of biomaterial in alveolar defect facilitates bone healing and orthodontic treatment. BMP2-functionalized biomimetic calcium phosphate (BioCaP) graft had shown excellent bone defect healing potential in many preclinical studies. In this study, we aimed to investigate the influence of BioCaP graft on surgical alveolar bone defect healing during orthodontic tooth movement (OTM) in beagle dogs.Methods: Nine Beagle dogs were randomly assigned to three groups: control, deproteinized bovine bone (DBB), and BioCaP. The maxillary second premolars were protracted into the defects of the extracted maxillary first premolar for 8 weeks. The rate of OTM, alveolar remodeling and bone defect healing were evaluated by histology, histomorphometry, and cone beam computed tomography (CBCT) imaging. Periodontal probing depth was analyzed. Gingival cervicular fluid was collected at week 4 and 8, and the IL-1β level was measured by ELISA.Results: The histological sections of the bone defect showed more newly formed bone in the BioCaP group. The percentage of new bone formation in the BioCaP group was 1.61-, and 1.25-fold higher compared to the control and DBB group, respectively. After 8 weeks of OTM, the resorption rate of BioCaP was 1.42-fold higher compared to DBB. The root resorption index in the DBB group was 1.87-, and 1.39-fold higher compared to the control and BioCaP group, respectively. CBCT images showed 1.92-, and 1.36-fold higher bone mineral density in the BioCaP group compared to the control and DBB group, respectively. There was no significant difference in OTM among the three groups. The distance between the enamel cementum and the crest of the alveolar ridge in the control group was 1.45-, and 1.69-fold higher compared to DBB and BioCaP group, respectively. Periodontal probing depth at week 8 was reduced in the BioCaP group compared to the control. IL-1β concentration in the gingival cervicular fluid was significantly lower in the BioCaP group compared to the control group at week 4 and 8.Conclusion: BioCaP graft robustly promoted bone regeneration and alveolar bone defect healing without affecting OTM. BioCaP graft caused less alveolar bone recession and root resorption of traction tooth with favorable periodontal attachment level indicating that BioCaP as a bioactive and functional bone filling material for alveolar bone defects during orthodontic treatment.

LncRNA Nron regulates osteoclastogenesis during orthodontic bone resorption

Activation of osteoclasts during orthodontic tooth treatment is a prerequisite for alveolar bone resorption and tooth movement. However, the key regulatory molecules involved in osteoclastogenesis during this process remain unclear. Long noncoding RNAs (lncRNAs) are a newly identified class of functional RNAs that regulate cellular processes, such as gene expression and translation regulation. Recently, lncRNAs have been reported to be involved in osteogenesis and bone formation. However, as the most abundant noncoding RNAs in vivo, the potential regulatory role of lncRNAs in osteoclast formation and bone resorption urgently needs to be clarified. We recently found that the lncRNA Nron (long noncoding RNA repressor of the nuclear factor of activated T cells) is highly expressed in osteoclast precursors. Nron is downregulated during osteoclastogenesis and bone ageing. To further determine whether Nron regulates osteoclast activity during orthodontic treatment, osteoclastic Nron transgenic (Nron cTG) and osteoclastic knockout (Nron CKO) mouse models were generated. When Nron was overexpressed, the orthodontic tooth movement rate was reduced. In addition, the number of osteoclasts decreased, and the activity of osteoclasts was inhibited. Mechanistically, Nron controlled the maturation of osteoclasts by regulating NFATc1 nuclear translocation. In contrast, by deleting Nron specifically in osteoclasts, tooth movement speed increased in Nron CKO mice. These results indicate that lncRNAs could be potential targets to regulate osteoclastogenesis and orthodontic tooth movement speed in the clinic in the future.

Asperosaponin VI Injection Enhances Orthodontic Tooth Movement in Rats.

BackgroundThis study was performed to investigate the effect of local injection of asperosaponin VI (ASA VI) on the orthodontic tooth movement in rats.Material/MethodsA total of 64 healthy female Sprague-Dawley rats were selected and divided into 2 groups randomly: the ASA VI group and the control group. For the ASA VI group, 10 mg/kg ASA VI solution was injected into buccal submucoperiosteal of bilaterally first maxillary molars, and the same volume of normal saline was given to the control group. The orthodontic force was applied to the maxillary first molars. All rats were sacrificed on days 3, 7, or 14. Tooth movement effects on the periodontium were analyzed through hematoxylin and eosin (H&E) staining, tartrate-resistant acid phosphatase (TRAP) staining and immunohistochemistry analysis. Tooth movement measurements and alveolar bone volumetric changes were analyzed using a micro-computed tomography (CT) scan. Molecular changes were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot.ResultsThe ASA VI group presented with a significant increase of tooth movement, osteoclast number, and the expression of osteoclast differentiation factor (ODF) compared with the control group. ASA VI also induced a significant decrease in bone volume and density and an increase in trabecular spacing and RANKL (receptor activator of nuclear factor kappa-B ligand) expression at the compression side. Furthermore, ASA VI stimulated bone formation on the tension side by enhancing OCN (osteocalcin) expression and RUNX2 (runt-related transcription factor 2) expression, increasing bone volume and density and decreasing in trabecular spacing.ConclusionsInjection of ASA VI may accelerate tooth movement via increasing the activity of osteoclasts, stimulating bone resorption at the compression side. Furthermore, ASA VI has a positive effect on bone formation at the tension side.

Anchorage loss in corticotomy assisted tooth movement

In orthodontic treatment, anchorage loss is a potential side effect of fixed mechanotherapy and one of the major causes of unsuccessful results, on the other hand considerable worry to the orthodontist. A major concern to the orthodontic patients is treatment time. Reducing the treatment time requires increasing the rate of orthodontic tooth movement. Orthodontic force induces a cellular response in the periodontal ligament, which brings about bone resorption on the pressure side and bone deposition on the tension side. Tooth movement can be accelerated by either employing certain adjunctive orthodontic procedures or by using advanced mechanotherapy. Aim: of this study is to compare and evaluate the anchor loss in corticotomy assisted cases and control cases without corticotomy. Materials and Methods: The study was conducted among 20 patients who were divided into two groups with 10 cases in each group. Group A patients were treated with corticotomy, allograft procedure along with fixed mechanotherapy while group B patients treated with convectional fixed mechanotherapy and was taken as controls and both groups underwent first bicuspid extractions and were treated with 0.022 MBT appliance. Result: Corticotomy assisted retraction cases had increased anchorage loss but was statistically insignificant compared to conventional method. Conclusion: Based on the outcome of this study, it is reasonable to conclude that corticotomy?assisted retraction cases had increased anchorage loss, compared to conventional retraction cases but was stastically insignificant, this may be due to a small sample size. Further studies are recommended on corticotomy?assisted retraction anchorage loss. Keywords: Anchorage loss, Corticotomy, First molar.

The effects of a clinically feasible application of low-level laser therapy on the rate of orthodontic tooth movement: A triple-blind, split-mouth, randomized controlled trial

This split-mouth trial aimed to investigate the effect of low-level laser therapy (LLLT) on the amount of maxillary canine distalization when applied every 4weeks over 12weeks. Twenty-two adolescents and young adults (15 female, 7 male; aged 13-25years; n=22) requiring bilateral maxillary first premolar extractions were recruited. After extractions and leveling-alignment, canines were retracted using closed-coil nickel-titanium springs delivering 150g of force. LLLT was applied to 8 intraoral points on the buccal and palatal sides around the canine root for 10seconds per point, on day 0, 28, and 56 with the control side receiving sham application. Alginate impressions were taken every 4weeks on day 0, 28, 56, and 84. The amount of tooth movement, anchorage loss, and canine rotation were measured digitally. Randomization was generated using www.randomisation.com and allocation concealment through sequentially numbered, opaque, sealed envelopes. Participants, operator, and statistic assessor were blinded. Linear regression modeling accounting for clustering within each patient was used to identify differences between LLLT and control sides. Twenty-one patients completed the study. The total amount of tooth movement was similar in the LLLT (2.55±0.73mm) and control group (2.30±0.86mm), whereas 0.25mm (95% confidence interval, -0.21, 0.71mm) of difference was insignificant (P=0.27). No significant differences were found for anchorage loss (P=0.22) or canine rotation (P=0.25). No harms were reported. Application of LLLT every 4weeks did not result in differences in the amount of tooth movement, anchorage loss, and canine rotation during extraction space closure.

Role of autophagy in the periodontal ligament reconstruction during orthodontic tooth movement in rats

Background/purposeAutophagy, a lysosome-based degradation pathway that is reportedly activated by mechanical stress and nutrient deprivation, plays an important role in various physiological and pathological events. The present study investigated the level of autophagy and tumor necrosis factor-α(TNF-α) expression in the periodontal ligaments (PDLs) of Sprague–Dawley (SD) rats to analyze the involvement of autophagy and inflammatory cytokines in orthodontic tooth movement (OTM) and maintaining periodontal tissue homeostasis.Materials and methodsSD rats (n = 100) were randomly divided into a control group (n = 10) and an experimental group (n = 90). An orthodontic appliance was placed in each rat in the experimental group, and 10 rats were randomly euthanized 15 min, 30 min, 1 h, 2 h, 4 h, 12 h, 1 d, 3 d and 7 d after mechanical loading. The OTM distance was then measured. Hematoxylin and eosin (HE) staining was used to analyze the morphology of the PDL. Immunohistochemical (IHC) staining and tartrate-resistant acid phosphatase (TRAP) staining were also performed.ResultsAfter the application of orthodontic force and under the dual effects of mechanical force and starvation caused by compressed vessels, the level of autophagy and TNF-α expression in the PDL fluctuated and exhibited a similar trend.ConclusionOur data suggest a significant correlation between the initiation of autophagy and TNF-α expression, which both exerted positive effects on PDL remodeling during OTM in rats.

DR3 and its ligands take roles in periodontium remodeling during orthodontic tooth movement

Background/purposeBased on ‘pressure-tension theory’, the application of orthodontic force to the tooth site affects the remodeling of periodontal tissue, specifically, mechanical stress induces the release of cytokines. The purpose of this research paper is to examine death receptor 3/TNF-like protein 1A/progranulin (DR3/TL1A/PGRN) expression levels in periodontium tissue during orthodontic tooth movement in rats. Materials and methodsThirty-six ten-week-old male SD rats were used in this study. A total of 20 cN of orthodontic force was exerted by coil springs onto the upper right first molars in order for mesialization purposes. All rat members of their corresponding groups were euthanized based on the following time intervals: 0 day for the control group, 1 day (group two), 3 days (group three), 5 days (group four), 7 days (group five), and lastly 14 days for group six. The effects of DR3/TL1A/PGRN were observed through the use of immunohistochemical staining techniques. One-way analysis of variance followed by a LSD t-test was performed by SPSS 20 to compare the differences of the level of DR3/TL1A/PGRN amongst each specified time interval. ResultsThe expression levels of DR3/PGRN increased significantly on day 14 compared to that of the control group, thus indicating a wide range of statistical differences. The expression levels of TL1A soared upwards on day 1, then plunged to an all-time low on day 7 before finally bouncing back to its initial value on day14. ConclusionDR3 and its two ligands—PGRN and TL1A play indispensable roles in regulating periodontal ligament remodeling during orthodontic tooth movement.

Effect of mini-screw-facilitated micro-osteoperforation on the rate of orthodontic tooth movement: a single-center, split-mouth, randomized, controlled trial

ObjectiveThe present study aimed to evaluate the effect of MOP over a 3-month period and to determine the influence of the number of perforations on the rate of canine retraction. In addition, the amount of pain and discomfort caused by the MOP method was evaluated.Trial designA single-center, split-mouth, triple-blind, randomized, controlled trial was conducted.MethodsThe clinical trial was conducted from December 2018 to July 2019 in the Orthodontic Clinic, Shiraz Dental School. Twenty-eight patients (range from16.3 to 35.2 years) who need fixed orthodontic treatment were recruited and randomly assigned to MOP1 and MOP2 groups. In each patient one side of the mouth worked as a control side which received no MOPs. Four months after first premolars extraction, patients in MOP1 group received 3 MOPs on the buccal surface of alveolar bone in the experimental side to accelerate canine retraction whereas patients in MOP2 group received 3 buccal MOPs and 3 palatal MOPs in the experimental side. The amount of canine retraction was measured every 28 days at three intervals on both sides of the mouth. Pain perception was also measured on the day of MOP procedure and subsequently at 24 h. Randomization was performed using online software RANDOM.ORG; the recruited patients were divided into two parallel groups with a 1:1 allocation ratio then the side of MOPs intervention in each subject was randomly determined with coin tossing. Triple blinding design was employed.ResultsThe result of the intra-examiner reliability using ICC was 0.97 (P < 0.001), indicating excellent repeatability and reliability of the measurements. The baseline characteristics between the groups were similar (P > 0.05). There was a significant difference in the rate of canine retraction between the MOP groups and the contralateral control sides, as well as between the MOP1 and MOP2 groups (P < 0.05).ConclusionThe MOP procedure was effective in accelerating orthodontic tooth movement, although the amount of acceleration was not clinically significant in the case of canine retraction. An increase in the number of MOPs resulted in a significant acceleration of the canine retraction.Trial registrationThe trial was registered 30 November 2018 at the Iranian Registry of Clinical Trials (IRCT20181121041713N1).

The Administration of 4-Hexylresorcinol Accelerates Orthodontic Tooth Movement and Increases the Expression Level of Bone Turnover Markers in Ovariectomized Rats.

Surgical methods for accelerating orthodontic tooth movement are limited by possible damage to the tooth root and patient discomfort. 4-Hexylresorcinol (4HR) has been shown to increase bone remodeling and may potentially facilitate tooth movement. This study investigated the (1) effect of 4HR administration on osteoblast-like cells and (2) effect of 4HR administration on tooth movement in ovariectomized rats. Saos-2 cells were treated with either 4HR or solvent (control). Protein expression levels were investigated 2, 8, and 24 h after treatment. Thirty ovariectomized Sprague-Dawley rats were divided into two experimental groups (A and B) and one control group. After installation of an orthodontic tooth movement device, groups A and B received subcutaneous weekly injections of 4HR (1.28 and 128 mg/kg). Micro-computerized tomography and histological analyses were performed after 2 weeks of tooth movement. The application of 4HR elevated expression of osteogenic markers in Saos-2 cells. Movement of the first molars was significantly greater in rats administered 4HR. Furthermore, the expression of bone morphogenic protein-2, receptor activator of nuclear factor kappa-B ligand, osteocalcin, and tartrate-resistant acid phosphatase were increased after 4HR administration. 4HR application demonstrated increased expression of osteogenic markers in Saos-2 cells and accelerated orthodontic tooth movement in rats.

Effect of Low Intensity Laser Therapy (LILT) on MMP-9 expression in gingival crevicular fluid and rate of orthodontic tooth movement in patients undergoing canine retraction: A randomized controlled trial

Low Intensity Laser Therapy (LILT) has been shown to increase the rate of tooth movement. Since its use in orthodontics as a method of acceleration there has been a variety of views regarding its mode of action. MMP-9 is a known bone resorption factor studied in Bone remodelling. The aim of this study was to know the effect of LILT on rate of tooth movement and expression of MMP-9 in GCF. Ten patients (3 males and 7 females) who required maxillary first premolar extraction for routine orthodontic treatment were recruited. The individual canine retraction was studied, and the side of the experimental canine was randomly selected. The laser regimen was followed on the 1st, 3rd, 5th, 7th, 14th and then 15th days consecutively. GCF was collected at baseline, 14th day, 3 months and at the end of canine retraction on experimental side and MMP-9 was estimated quantitatively using a standard ELISA kit. The average increase in rate of tooth movement on experimental side at 3 months was 44% and MMP-9 concentration was also high. At the end of canine retraction (4.5 months) in the experimental group the average rate increase was 38% with MMP-9 concentrations similar in both the experimental and control group. LILT increases the rate of tooth movement. LILT also has an effect of bio-stimulation as depicted by rise in MMP-9 concentrations in GCF. However, this bio-stimulatory effect is restricted to the initial part of the tooth movement.

Effect of platelet-rich plasma on the rate of orthodontic tooth movement.

To investigate the effect of local injection of platelet-rich plasma (PRP) on the rate of orthodontic tooth movement. Sixteen female patients were randomly allocated in a split-mouth study design to receive PRP injections with CaCl2 activating solution on one side (intervention side) while the other side received CaCl2 injection only (control side). Canine retraction was performed on 0.017 × 0.025-inch stainless steel archwire applying 1.5 N retraction force. PRP and CaCl2 injections were done at 0, 3, and 6 weeks. The duration of the study was 4 months. Data were collected from digitized models. Assessment of pain accompanying the procedure was done using a visual analogue scale. The rate of canine retraction was faster on the intervention side in the first 2 months, with a statistically significant difference in the first month (P = .049). On the other hand, the rate was statistically significantly slower on the intervention side in the third month following cessation of PRP injections (P = .02). Pain increased following injections on both sides. PRP showed a positive potential to accelerate the rate of tooth movement when injected in the first 2 months. Repeated injections of PRP to maintain a steady rate of accelerated tooth movement warrant further investigation.

Age effect on orthodontic tooth movement rate and the composition of gingival crevicular fluid : Aliterature review.

To evaluate and form acomprehensive understanding of the effect of patient age on bone remodeling and consequently on the rate of orthodontic tooth movement (OTM). Asystematic search in PubMed and Embase from 1990 to December 2017 was performed and completed by ahand search. Prospective clinical trials which investigated the rate of OTM and/or studies assessing age-related changes in the composition of gingival crevicular fluid (GCF) in older compared to younger study groups were included. Study selection, data extraction and risk of bias were assessed by two authors. Eight studies fulfilled the inclusion criteria. Among them, four evaluated the rate of OTM and six investigated mediators in the GCF (prostaglandin E2, interleukin [IL]-1β, IL‑6, IL‑1 receptor antagonist, receptor activator of nuclear factor kappa‑Β ligand, osteoprotegerin, granulocyte-macrophage colony-stimulating factor, pentraxin3). Patient age ranged between 16 and 43years for older and <16years for younger groups. In most of the studies, the younger patients showed faster OTM in the first phase of treatment and more pronounced cytokine levels. Older patients had adelayed reaction to orthodontic forces. The small number of included studies and large heterogeneity in study design give limited clinical evidence that the older patients are less responsive to orthodontic force in comparison to younger patients. The initial cellular response to orthodontic force is expected to be delayed in older patients. Control intervals during orthodontic treatment should be adjusted to the individual's treatment response.

The effect of low-level light therapy on orthodontic tooth movement rate, heat shock protein 70, and matrix metallopreteinase 8 expression: Animal study

The aim of this study was to determine the effect of low-level light therapy (LLLT) on orthodontic tooth movement (OTM) rate, heat shock protein 70 (HSP-70) expression, and matrix metalloproteinase 8 (MMP-8) expression. In this experimental study twenty-four male guinea pigs were randomly divided into three groups (n = 8): control group (K) without orthodontic force and LLLT; treatment group 1 (T1) with orthodontic force, and treatment group 2 (T2) with orthodontic force and LLLT. The labial surfaces of both maxillary central incisors in treatments groups were installed with single-wing bracket before being inserted with close coil spring to give 10 g/cm2 orthodontic force. For the T2 group, 4 J/cm2 of LLLT was administered in the mesial-distal and labial-palatal regions for 3 min every day. On day 14, the gap between teeth was measured and immunohistochemistry staining was done to determine HSP-70 and MMP-8 expression. Data were analyzed using (IBM, New York, (ANOVA), followed by Turkey's HSD test to determine the differences between groups. Nonnormal distributed data would be analyzed using Kruskal-Wallis test, followed by Mann-Whitney test with P < 0.05 being performed. The gap between teeth in the T2 group was greater compared to T1 group (P = 0.00). However, there was a significant decrease of HSP-70 and MMP-8 expression in T2 group compared to T1 group in the tensile and compressive sides. LLLT intervention during orthodontic treatment could accelerate OTM rate and decreased HSP-70 and MMP-8 expression both in tension and in compressive side. Thus, LLLT interventions can be used as adjuvant therapy to shorten orthodontic treatment duration.

Effect of amitriptyline on orthodontic tooth movement in rats: an experimental study.

Background. Orthodontic tooth movement (OTM) occurs in the alveolar bone; therefore, any condition affecting bone quality can alter OTM. This study aimed to evaluate the effect of amitriptyline on OTM in rats. Methods. Forty-five male Wistar rats were randomly divided into three groups: (I) no injection, (II) injection with saline solution, and (III) injection of amitriptyline. Next, a 60-gr force was applied to the maxillary left first molar tooth of all the rats, using a nickel‒titanium closed-coil spring ligated between the maxillary incisors and the left first molar tooth. The rats were sacrificed after 21 days to measure OTM and perform histological analysis to determine the number, width, and depth of resorptive lacunae, osteoclast counts, and periodontal ligament (PDL) width. Results. The highest and the lowest OTM rates were found in the control and amitriptyline groups, respectively; however, there was no significant difference between the study groups in this regard. Histological analysis showed a significantly lower number of resorption lacunae in the amitriptyline group than the saline group. Conclusion. Although no significant difference was noted in OTM after amitriptyline administration, a reduction in the number of resorptive lacunae in rats injected with amitriptyline suggests that amitriptyline affects the bone tissue at the cellular level.

Effect of Cocoa Administration on Osteoblast Counts and Alkaline Phosphatase Levels During Orthodontic Tooth Movement in Rats

Introduction: The cocoa effect on osteoblast activity during orthodontic tooth movement remains unknown. To analyze the effect of caffeine in cocoa on osteoblast counts and alkaline phosphatase (ALP) levels during orthodontic tooth movement. Materials and Methods: The subjects used in this study were 24 male Sprague–Dawley rats aged 2.5–3 months. They were divided into treatment and control groups (n =1 2). A three-spin stainless steel coil spring with a 35 cN orthodontic force was stabilized on the maxillary incisors. The rats in the treatment group were given 4.8 g of cocoa powder with 2.7 mg of caffeine. All the subjects were euthanized in four consequent time periods (0, 1, 7, and 14 days), and tissue specimens were stained with hematoxylin-eosin. Osteoblasts were observed and counted under a light microscope with an Optilab camera at 400× magnification. ALP levels were examined through ELISA. Data were analyzed through two-way ANOVA followed by LSD post-hoc test. Results: Significant differences were observed in the control and treatment groups and the time of observing osteoblast count and ALP levels (P