Closed Coil Spring Research Articles

Influence of human parathyroid hormone during orthodontic tooth movement and relapse in the osteoporotic rat model: A preliminary study.

To investigate the effects of parathyroid hormone (PTH) on tooth movement in ovariectomized (OVX) rats by comparing the tooth movement distance and relapse and by examining the alveolar bone microstructure. Thirty 8-week-old female rats were classified into 3 groups: sham-operated, OVX and ovariectomized rats injected with PTH (PTH). Eight weeks later, a closed-coil spring appliance was placed between the maxillary incisor and the first molar and then activated with 50cN of force. During tooth movement, 30μg/kg of PTH was administered 3 times per week in the PTH group. Tooth movement distances were measured weekly. Five rats in each group were killed after 3weeks for microcomputerized tomographic analysis, and the remaining 5 rats in each group were killed at an additional 3weeks after the removal of the appliance to measure relapsed distance. The OVX group showed significantly greater tooth movement compared to those in the other 2 groups at 2 and 3weeks (P<.05). The relapse distance and relapse percentage for the OVX group were higher; however, it did not differ significantly from the PTH group. On micro-CT analysis, bone volume/tissue volume ratio and bone mineral density in the PTH group were significantly greater than in the OVX group (P<.05). Application of PTH did not promote tooth movement in OVX rat, however, did lead to decrease in relapse tendency. Therefore, the application of PTH during orthodontic treatment of patients with osteoporosis should be carefully considered.

Reduced Orthodontic Tooth Movement in Enpp1 Mutant Mice with Hypercementosis

Previous studies revealed that cementum formation is tightly regulated by inorganic pyrophosphate (PPi), a mineralization inhibitor. Local PPi concentrations are determined by regulators, including ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1), which increases PPi concentrations by adenosine triphosphate hydrolysis. Orthodontic forces stimulate alveolar bone remodelling, leading to orthodontic tooth movement (OTM). To better understand how disturbed mineral metabolism and the resulting altered periodontal structures affect OTM, we employed Enpp1 mutant mice that feature reduced PPi and increased cervical cementum in a model of OTM induced by a stretched closed-coil spring ligated between the maxillary left first molar and maxillary incisors. We analyzed tooth movement, osteoclast/odontoclast response, and tooth root resorption by micro–computed tomography, histology, histomorphometry, and immunohistochemistry. Preoperatively, we noted an altered periodontium in Enpp1 mutant mice, with significantly increased periodontal ligament (PDL) volume and thickness, as well as increased PDL-bone/tooth root surface area, compared to wild-type (WT) controls. After 11 d of orthodontic treatment, Enpp1 mutant mice displayed 38% reduced tooth movement versus WT mice. Molar roots in Enpp1 mutant mice exhibited less change in PDL width in compression and tension zones compared to WT mice. Root resorption was noted in both groups with no difference in average depths, but resorption lacunae in Enpp1 mutant mice were almost entirely limited to cementum, with 150% increased cementum resorption and 92% decreased dentin resorption. Osteoclast/odontoclast cells were reduced by 64% in Enpp1 mutant mice, with a predominance of tartrate-resistant acid phosphatase (TRAP)–positive cells on root surfaces, compared to WT mice. Increased numbers of TRAP-positive cells on root surfaces were associated with robust immunolocalization of osteopontin (OPN) and receptor-activator of NF-κB ligand (RANKL). Collectively, reduced response to orthodontic forces, decreased tooth movement, and altered osteoclast/odontoclast distribution suggests Enpp1 loss of function has direct effects on clastic function/recruitment and/or indirect effects on periodontal remodeling via altered periodontal structure or tissue mineralization.

Evaluating the Amount of Tooth Movement and Root Resorption during Canine Retraction with Friction versus Frictionless Mechanics Using Cone Beam Computed Tomography.

BACKGROUND:The current study was carried out to compare the amount of tooth movement during canine retraction comparing two different retraction mechanics; friction mechanics represented by a NiTi closed coil spring versus frictionless mechanics represented by T - loop, and their effect on root resorption using Cone Beam Computed Tomography (CBCT).METHOD:Ten patients were selected in a split-mouth study design that had a malocclusion that necessitates the extraction of maxillary first premolars and retraction of maxillary canines. The right maxillary canines were retracted using T - loops fabricated from 0.017 X 0.025 TMA wires. The left maxillary canines received NiTi coil spring with 150 gm of retraction force. Pre retraction and post retraction Cone Beam Computed Tomography were taken to evaluate the amount of tooth movement and root resorption using three-dimensional planes.RESULTS:T - loop side showed statistically significant higher mean anteroposterior measurement than NiTi coil spring side, indicating a lower amount of canine movement pre and post a canine retraction. Concerning the root resorption, there was no statistically significant change in the mean measurements of canine root length post retraction.CONCLUSION:The NiTi coil spring side showed more distal movement more than the T-loop side. Both retraction mechanics with controlled retraction force, do not cause root resorption.

An Intraoral Appliance to Retract the Protrusive Premaxilla in Bilateral Cleft Lip Patients Presenting Late for Primary Lip Repair.

The protruding and deviated premaxilla in bilateral complete cleft lip and palate (BCL/P) patients causes a perplexing problem in achieving a tension-free primary lip closure. An innovative noninvasive active intraoral Fixed Pre-Surgical Cleft Orthopedic (FPSCO) appliance is presented that has enabled to successfully reposition the premaxillary segment to a more favorable position prior to the surgical repair in 4 BCL/P patients, who reported late for treatment with a mean age of 18 ± 3 months. All the patients had at least 1 deciduous tooth erupted in 3 cleft segments, 1 premaxilla (PM), and 2 lateral maxillary (LM) segments. This innovative approach is a noninvasive method of getting the cleft segments closer prior to chelioplasty, where conventional presurgical nasoalveolar molding (PNAM) is not possible, which needs to be done early in life as it requires circulating maternal estrogen levels to achieve results preferably possible in patients younger than 3 to 6 months. Bonding to erupted teeth with glass ionomer cement was implemented to secure the appliance. Nickel-titanium (Ni-Ti) closed-coil springs were used that delivered continuous forces of 150 g/5 oz per side to retract the premaxillary segment. The mean active period of treatment time was 3.5 ± 1.6 months and the retention period was 1.2 ± 0.6 months, following which cheiloplasty was performed.

Levels of Tumor Necrosis Factor-α (TNF-α) and Transforming Growth Factor-β1 (TGF-β1) in Gingival Crevicular Fluid During Canine Retraction Using Elastic Chain and Closed Coil Spring

Introduction: To investigate the levels of human tumor necrosis factor-α (TNF-α) and transforming growth factor β1 (TGF-β1) in gingival crevicular fluid (GCF) during canine retraction movement using elastic chains and closed coil springs. Materials and Methods: One hundred patients (49 men and 51 women; mean age, 23.6 years) entering the space closure phase of fixed orthodontic treatment participated in this research. An upper canine of each patient was retracted using an elastic chain, and the contralateral canine was retracted using a closed coil spring. GCF samples were collected from the canine before and 7 days after the force was applied. human TNF-α and TGF-β1 were determined by enzyme-linked immunosorbent assay. Results: There were significant increase in the concentrations of both TNF-α and TGF-β1 at 7 days in both groups (P

Effect of caspases and RANKL induced by heavy force in orthodontic root resorption.

ObjectiveOrthodontic root resorption (ORR) due to orthodontic tooth movement is a difficult treatment-related adverse event. Caspases are important effector molecules for apoptosis. At present, little is known about the mechanisms underlying ORR and apoptosis in the cementum. The aim of the present in vivo study was to investigate the expression of tartrate-resistant acid phosphatase (TRAP), caspase 3, caspase 8, and receptor activator of nuclear factor kappa-B ligand (RANKL) in the cementum in response to a heavy or an optimum orthodontic force.MethodsThe maxillary molars of male Wistar rats were subjected to an orthodontic force of 10 g or 50 g using a closed coil spring. The rats were sacrificed each experimental period on days 1, 3, 5, and 7 after orthodontic force application. And the rats were subjected to histopathological and immunohistochemical analyses.ResultsOn day 7 for the 50-g group, hematoxylin and eosin staining revealed numerous root resorption lacunae with odontoclasts on the root, while immunohistochemistry showed increased TRAP- and RANKL-positive cells. Caspase 3- and caspase 8-positive cells were increased on the cementum surfaces in the 50-g group on days 3 and 5. Moreover, the number of caspase 3- and caspase 8-positive cells and RANKL-positive cells was significantly higher in the 50-g group than in the 10-g group.ConclusionsIn our rat model, ORR occurred after apoptosis was induced in the cementum by a heavy orthodontic force. These findings suggest that apoptosis of cementoblasts is involved in ORR.

Effects of continuous force application for extrusive tipping movement on periapical root resorption in the rat mandibular first molar.

ObjectiveThe purpose of this study was to clarify the effects of continuous force application for extrusive tipping movement and occlusal interference on periapical root resorption in the rat mandibular first molar.MethodsWe constructed an appliance comprising a titanium screw implant with a cobalt-chromium post as the anchorage unit and a nickel-titanium closed coil spring (50 cN) as the active unit. Force was applied on the mandibular left first molar of rats for 8 (n = 10) and 15 days (n = 10; experimental groups), with the tooth in occlusion. Five rats were included as a non-treated control group to examine the body effect of the appliance. Active root resorption lacunae, identified using tartrate-resistant acid phosphatase, were evaluated in terms of the length, depth, and area.ResultsThe rat mandibular first molars were mesially tipped and extruded in the occlusal direction. This mesio-occlusal tipping movement and occlusion resulted in the formation of a compression zone and active root resorption lacunae in the distoapical third of the distal roots. However, there was no significant difference in the amount of root resorption between the two experimental groups. The control group did not exhibit any active root resorption lacunae.ConclusionsPeriapical root resorption was induced by continuous extrusive tipping force and occlusal interference in rat mandibular molars. These data suggest that we orthodontists had better take care not to induce occlusal interference during our orthodontic treatment.

Comparative clinical and laboratory study of the force loss generated by NiTi closed coil springs

The purpose in this study was to compare the force decay of laboratory and clinical NiTi closed coil springs. Specimens were 30 NiTi coil springs (clinical) and 15 (laboratory in artificial saliva 36.6 ºC) springs were tested by dynamometer to evaluate force loos at different intervals: 1, 2 and 3 months of use. Data (gF) were analyzed statistically using. Clinical and laboratory data were compared to evaluate effect of the oral environment on force loss. It was observed a significant force loss of NiTi springs. NiTi springs showed force loss (13.2%) at 28 days of clinical use, with a further significant loss from 4-12 weeks (~21%); force levels remained steady thereafter. Were not statistically different in clinical and laboratory force loss data. Space was closed at an average rate of 1 mm/month.

An in vitro study of the stretching time-associated force loss generated by elastomeric chains and NiTi closed coil springs

The study samples comprised 40 elastomeric chains (20 Dentaurum, and 20 G & H) and 15 NiTi closed spring (GAC). The elastomeric chains were submerged in 36,6 ºC artificial saliva and stretched on the instrument of resin plates at a distance of 30 mm. With an electronic dynamometer the delivered force was evaluated at different intervals: at baseline, after 1 day, 4, 7, 14, 21 and 28 days. Specimens of 15 NiTi coil springs were tested by dynamometer to evaluate force loss following 1, 2, or 3 months of use. It was observed a significant force loss of elastomeric chains after 24 hours. There was a force loss of elastomeric chains (from 34±1.3% to 53.86±2% after 28 days of activation). NiTi springs showed force loss (~13%) following 28 days of use, with a further significant loss (~6%) at 4-8 weeks; force levels remained steady thereafter. There was higher force loss in the different commercially elastomeric chains (~60%) in comparison to NiTi springs (21%).

Na18F accumulates on the compressive side of peri-implant bone under immediate loading.

This study aimed to examine the dynamic change in bone metabolism by immediate loading in several sites around implants using high-resolution Na18F-PET scan. Two titanium implants (Ø 1.2mm) were inserted parallel to each other in the right tibiae of Wistar rats (n=4). The left tibia was set as control side. One day after insertion, closed coil springs of 4.0N were attached to the expose superior portions of the implants to apply a continuous mechanical stress. The rats with fluorine-18 (18F) ion (5mCi/rat) intravenously injected were scanned by PET scanner at 4, 7, 14, 28days after load application. Round region of interests (ROIs) were set around the distal implant of the right tibia (loaded side) and same site (control) of the left tibia. Furthermore, four rectangular ROIs were set at the superior and inferior parts of traction side (mesial) and opposite side (distal) of the distal implant. Longitudinal dynamic changes in bone metabolism were evaluated by examination of the accumulation count of 18F ion at each ROI. The uptake values of ROIs (loaded side) initially increased until 7days, and they gradually decreased from the peak level to the pre-loading level despite a static force being applied to the implants. In cancellous bone, the uptake values at the superior part of traction side and inferior part of opposite side showed significantly high value compared with those at other parts. In conclusion, immediate loading to the implant initially enhanced bone metabolism around it, especially at the part with compressive stress. Peri-implant bone metabolism varies according to different loading conditions.

Effect of micro-osteoperforations on the rate of canine retraction: a split-mouth randomized controlled clinical trial

INTRODUCTION: The prolonged orthodontic treatment time is considered a major concern both for patients and clinicians.Corticotomy has been proposed as a method for acceleration of orthodontic tooth movement and was found successful. However, its popularity decreased because of its invasiveness. Micro-osteoperforations have been proposed for acceleration with minimal invasiveness. OBJECTIVE: The purpose of the study was to clinically evaluate the effect of micro-osteoperforations on the rate of orthodontic tooth movement as evaluated by its effect on the rate of canine retraction. MATERIALS AND METHODS: The study was a split-mouth randomized controlled clinical trial, with a sample size of 10 adult patients (mean age 17.5±2.5 years) requiring the therapeutic extraction of maxillary first premolars’ followed by canine retraction. Micro-osteoperforations were randomly assigned to one side of the maxillary arch at the canine-premolar region, and the contra-lateral side served as control. Anchorage reinforcement was performed usingmini-screws, and canine retraction was performed using nickel-titanium closed coil springs, delivering a force of 150 grams on each side. The rate of canine retraction was measured throughout the study period from dental models obtained at the follow-up visits every 3 weeks. RESULTS: The average daily rate of canine retraction was significantly higher on the experimental side compared to that on the control side by approximately 2 times during the first 9 weeks of the study. CONCLUSION: Micro-osteoperforations have been found clinically successful in accelerating orthodontic tooth movement and shortening the treatment duration. However, acceleration of tooth movement has been found significant during the first 9 weeks, which represent the period of regional acceleratory phenomenon.

The chemokine receptor type 4 antagonist, AMD3100, interrupts experimental tooth movement in rats

ObjectiveThe aim of this study was to clarify the role of the stromal cell-derived factor-1 (SDF-1)/C-X-C chemokine receptor type 4 (CXCR4) axis in osteoclast accumulation, and the influence of orthodontic tooth movement (OTM) under mechanical force application to periodontal tissues, by administration of the CXCR4 antagonist AMD3100. DesignThe upper right first molar (M1) of rats was moved mesially with a 10-g force titanium-nickel closed coil spring. Rats were treated with phosphate-buffered saline or AMD3100 (5mg/kg), which is a SDF-1 antagonist. After 0, 1, 3, and 7days, alveolar bones in all groups were examined at each time point by micro-computed tomography and histological analysis. ResultsTooth movement was decreased significantly in the AMD3100-treated group at 1, 3, and 7days after beginning OTM. The numbers of tartrate-resistant acid phosphatase-positive multinucleated cells in the periodontal ligament around the maxillary M1 were decreased significantly in the treated as compared to the control group on Days 1 and 3. ConclusionAdministration of AMD3100 decreases OTM and osteoclast accumulation in rat molars under orthodontic force application. These findings suggest that the SDF-1/CXCR4 axis plays an important role in alveolar bone metabolism during OTM.

Effects of low-level laser irradiation on the rate of orthodontic tooth movement and associated pain with self-ligating brackets.

The aim of this study was to evaluate the effect of low-level laser irradiation applied at 3-week intervals on orthodontic tooth movement and pain associated with orthodontic tooth movement using self-ligating brackets. Twenty-two patients (11 male, 11 female; mean age, 19.8±3.1years) with Angle Class II Division 1 malocclusion were recruited for this split-mouth clinical trial; they required extraction of maxillary first premolars bilaterally. After leveling and alignment with self-ligating brackets (SmartClip SL3; 3M Unitek, St Paul, Minn), a 150-g force was applied to retract the canines bilaterally using 6-mm nickel-titanium closed-coil springs on 0.019 x 0.025-in stainless steel archwires. A gallium-aluminum-arsenic diode laser (iLas; Biolase, Irvine, Calif) with a wavelength of 940nm in a continuous mode (energy density, 7.5J/cm2/point; diameter of optical fiber tip, 0.04cm2) was applied at 5 points buccally and palatally around the canine roots on the experimental side; the other side was designated as the placebo. Laser irradiation was applied at baseline and then repeated after 3weeks for 2 more consecutive follow-up visits. Questionnaires based on the numeric rating scale were given to the patients to record their pain intensity for 1week. Impressions were made at each visit before the application of irradiation at baseline and the 3 visits. Models were scanned with a CAD/CAM scanner (Planmeca, Helsinki, Finland). Canine retraction was significantly greater (1.60±0.38mm) on the experimental side compared with the placebo side (0.79±0.35mm)(P<0.05). Pain was significantlyless on the experimental side only on the first day after application of LLLI and at the second visit (1.4±0.82 and 1.4±0.64) compared with the placebo sides (2.2±0.41 and 2.4±1.53). Low-level laser irradiation applied at 3-week intervals can accelerate orthodontic tooth movement and reduce the pain associated with it.

EFFECT OF SURFACE TREATMENT OF ORTHODONTIC MINI-SCREW IMPLANTS ON THEIR STABILITY; IN VIVO STUDY

Purpose: To evaluate the effect of anodization surface treatment on the stability of minimplants ( MIs ) during en-masse retraction. Materials and Methods: The sample of this split mouth; clinical trial, consisted of 27 patients with an allocation ratio of 1:1. Forty five MIs (1.8 mm diameter and 8 mm length) were divided into: 27 MIs with surface treatment by anodization technique while the other 27 were with smooth surface (group B). Finishing, leveling and alignment, the surface treated MIs and the smooth ones were randomly inserted between the roots of maxillary 2nd bicuspid and 1st molar at the mucogingival junction on both sides of each patient. After two weeks healing period, bilateral extraction of maxillary 1st bicuspids were done. Closed coil spring was extended from the MI head to along hock secured onto the main arch wire between the maxillary lateral incisor and canine on both sides, delivering 200 g force per side to en-masse retract the upper anterior teeth. The average observation period lasted 9–12 months. Results: In total, 40 of 54 minimplants were able to achieve the treatment goals. In group A, 22 (81.5%) mini-screw implants presented long-term stability, while in group B, only 18 (66%) minimplants were stable throughout the treatment. This difference was statistically significant (P =.0311). The total success rate for all inserted miniscrew implants was 74%. Conclusion: Anodized surface treated orthodontic mini-screw implants are more stable than smooth surface one during en-mass retraction.

W Spring for Management of Impacted Teeth

Forced eruption of an impacted tooth necessitates a firm and versatile attachment for force application. The present article describes a simple modification of NiTi closed coil spring called W spring for predictable forced eruption of impacted teeth.

Treatment of Class II, Division 2 Malocclusion with Miniscrew Supported En-Masse Retraction: Is Deepbite Really an Obstacle for Extraction Treatment?

A 17-year-old female patient, whose chief complaint was her unpleasing smile, had skeletal and dental class II malocclusion, hypodivergent facial type with a severely increased overbite. Among the treatment options, upper-first-premolar extractions followed by miniscrew-supported en-masse retraction was the treatment of choice. After the initial levelling and alignment, miniscrews with 1.5- to 1.4-mm diameter and 7-mm lenght, were installed between the roots of the second premolars and the first molars, bilaterally. En-masse retraction was achieved on a 0.016×0.022-inch stainless steel archwire with 7-mm long power hooks placed distal to the lateral incisors, and with nickel-titanium (NiTi) closed coil springs exerting 250-gr of force per side. At the end of the treatment, deepbite, incisor inclinations and interincisal angle were corrected, and Class II molar relationship with good intercuspation was achieved. Upper 2-2, lower 3-3 retainers were bonded for retention. As a result, deepbite and Class II canine relationship was successfully corrected with simultaneous incisor intrusion and retraction using miniscrew-supported en-masse retraction.

Regular nicotine intake increased tooth movement velocity, osteoclastogenesis and orthodontically induced dental root resorptions in a rat model

Orthodontic forces have been reported to significantly increase nicotine-induced periodontal bone loss. At present, however, it is unknown, which further (side) effects can be expected during orthodontic treatment at a nicotine exposure corresponding to that of an average European smoker. 63 male Fischer344 rats were randomized in three consecutive experiments of 21 animals each (A/B/C) to 3 experimental groups (7 rats, 1/2/3): (A) cone-beam-computed tomography (CBCT); (B) histology/serology; (C) reverse-transcription quantitative real-time polymerase chain reaction (RT-qPCR)/cotinine serology—(1) control; (2) orthodontic tooth movement (OTM) of the first and second upper left molar (NiTi closed coil spring, 0.25 N); (3) OTM with 1.89 mg·kg−1 per day s.c. of L(−)-nicotine. After 14 days of OTM, serum cotinine and IL-6 concentration as well as orthodontically induced inflammatory root resorption (OIIRR), osteoclast activity (histology), orthodontic tooth movement velocity (CBCT, within 14 and 28 days of OTM) and relative gene expression of known inflammatory and osteoclast markers were quantified in the dental-periodontal tissue (RT–qPCR). Animals exposed to nicotine showed significantly heightened serum cotinine and IL-6 levels corresponding to those of regular European smokers. Both the extent of root resorption, osteoclast activity, orthodontic tooth movement and gene expression of inflammatory and osteoclast markers were significantly increased compared to controls with and without OTM under the influence of nicotine. We conclude that apart from increased periodontal bone loss, a progression of dental root resorption and accelerated orthodontic tooth movement are to be anticipated during orthodontic therapy, if nicotine consumption is present. Thus patients should be informed about these risks and the necessity of nicotine abstinence during treatment.

ANALISIS VEGF PADA PERGERAKAN GIGI ORTODONTI SETELAH PEMBERIAN SEDUHAN KOPI ROBUSTA ( COFFEACANEPHORA)

Background: Orthodontic tooth movement depends on bone remodeling. VEGF plays an important role in bone remodeling in both pressure area and tension area. Robusta coffee contains caffeine, chlorogenic acid and caffeic acid. Caffeine may increase osteoclastogenesis, and caffeic acid has antioxidant effects that may reduce oxidative stress in osteoblasts Objective: To analysis of VEGF of orthodontic tooth movement post robusta coffeesteeping administration. Material and methods: The experimental laboratories research used 16rats were divided into 2 groups. Group A: the rats were applied with orthodontic mechanical force (OMF) and group B: OMF + coffee steeping of 20mg /100 g of BW. OMF was conducted by applying ligature wire with a diameter of 0.20 mm on the molar-1 (M-1) and both incivus of right maxilla. Subsequently, M-1 of right maxilla was moved to mesial with Niti closed coil spring. Observations were made on days 15 and 22 by taking the gingival crevicular fluid by putting paper point on the gingival sulcus of mesio-and disto-palatal area of M-1 of right maxilla to determine the levels of VEGF using ELISA method. Results: the administration of Robusta coffee steeping increased the levels of VEGF in both compression area and tension area (p &lt;0.05).The levels of VEGF in tension area larger than the compression area(p &gt;0.05).Conclusion: the Robusta coffee steeping administration increased the levels of VEGF oforthodontic tooth movement ,therefore it may improve alveolar bone remodeling process and it may be an alternative to accelerate orthodontic treatment.

PENGARUH EKSTRAK KOPI ROBUSTA TERHADAP EKSPRESI OSTEOKALSIN PADA OSTEOBLAS SELAMA PERGERAKAN GIGI ORTODONTI

The objective of research is to determine the expression of osteocalcin on osteoblasts during orthodontic tooth movement after administration robusta coffee extract. Materials and Methods: 16 rats were divided into 2 groups: group K: rats applied with orthodontic mechanical force (OMF) and group P: OMF + coffee robusta extract of 20mg /100 g of BW. OMF was conducted by applying ligature wire on permanent maxillary right first molar and both permanent maxillary incisivus. Subsequently, the permanent maxillary right first molar moved to mesial with Ni-Ti orthodontic closed coil spring. Observations were made on day 15 by immunohistochemical examination to determine the expression of osteocalcin. Results: Robusta coffee extract improved the expression of osteocalcin in the compression and tension areas (p &lt;0.05). Expression of osteocalcin in tension area larger than that in compression area (p &lt;0.05). Conclusion: The administration of Robusta coffee extract increases the expression of osteocalcin, which can increase alveolar bone remodeling.

Effects of calcitonin on orthodontic tooth movement and associated root resorption in rats

Objectives: Our main aim was to evaluate the effects of calcitonin (CT) on orthodontic tooth movement (OTM) and orthodontic root resorption in a rat model.Material and methods: Eighty male Wistar rats were randomly divided into five groups. Rats in the negative control group were not given any appliances or injections. All the remaining rats were used to establish a model of OTM. The positive control group were then injected with normal saline, while rats in the three experimental groups were injected with 0.2 IU, 1 IU or 5 IU/kg/day CT. Nickel-titanium closed-coil springs were used to deliver an initial 50 g mesial force to the left maxillary first molar for 14 days in rats in the positive control group and the experimental groups. Each group was randomly subdivided into two groups, one for analysis of tooth movement, tissue changes and tartrate-resistant acid phosphatase (TRAP)-positive cells in alveolar bone, the other to examine root resorption by scanning electron microscopy.Results: The OTM distance, the number of force-induced osteoclasts and root resorption areas were significantly decreased in CT-injected rats in a dose-dependent manner.Conclusions: Administration of CT reduces the root resorption area and may therefore be effective as a novel adjunctive orthodontic approach to diminish undesired tooth movement via enhancing anchorage or preventing relapse after OTM.