Stage Of Orthodontic Tooth Movement Research Articles

Evaluation of heat shock protein 70 and toll-like receptor 4 expression in gingival crevicular fluid in response to orthodontic forces.

The aim of this study was to assess the concentrations of heat shock protein 70 (HSP70) and toll-like receptor 4 (TLR4) during orthodontic tooth movement and to compare their levels with interleukin-1β (IL-1β), a well-known proinflammatory biomarker. This study consisted of 20 patients (8 males, 12 females; mean age 14.75 ± 2.34years) who needed maxillary premolar extraction and segmental canine distalization. Concentrations of HSP70, TLR4, and IL-1β were examined before extraction (T1), at the 1st (T2), 4th (T3), 7th (T4), 14th (T5), and 30th (T6) days of canine retraction by enzyme-linked immunosorbent assay analysis of gingival crevicular fluid samples. Statistical analyses were performed with repeated measure ANOVA and Spearman's rank correlation coefficient analysis (p < 0.05). HSP70 increased gradually from T1 to T6 and showed significant differences between T1-T6 and T2-T6 (T1:3.28 ± 0.92ng/ml; T2:3.72 ± 0.66ng/ml; T6:9.35 ± 2.45ng/ml). The lowest TLR4 concentration was at T1, peaked at T3 and remained constant afterwards with significant differences between T1-T3, T1-T4, and T1-T6 (T1:0.71 ± 0.02pg/ml; T3:1.04 ± 0.11pg/ml; T4:0.95 ± 0.06pg/ml; T6:1.00 ± 0.07pg/ml). IL-1β increased from T1 to T6 with significant differences between T1-T4, T1-T5, and T1-T6 (T1:55.71 ± 5.48pg/ml; T4:100.11 ± 16.92pg/ml; T5:103.71 ± 23.19pg/ml; T6:125.12 ± 22.04pg/ml). The increase in HSP70 and TLR4 from T2-T3 showed a significant correlation (r = 0.598; p = 0.005). The increased levels of HSP70, TLR4, and IL-1β show the contribution of these mediators to the inflammatory response from the early stages of orthodontic tooth movement. The regulation of HSP70, TLR4, and/or IL-1β secretion during orthodontic force application could provide alterations for desired optimal tooth movement.

The role of endothelin B receptor in bone modelling during orthodontic tooth movement: a study on ETB knockout rats

The endothelin system has an important role in bone modelling during orthodontic tooth movement (OTM); however, little is known about the involvement of endothelin B receptors (ETB) in this process. The aim of this study was to evaluate the role of ETB in bone modelling during OTM using ETB knockout rats (ETB-KO). Thirty-two male rats were divided into 4 groups (n = 8 per group): the ETB-KO appliance group, ETB-KO control group, wild type (ETB-WT) appliance group, and ETB-WT control group. The appliance consisted of a super-elastic closed-coil spring placed between the first and second left maxillary molar and the incisors. Tooth movement was measured on days 0 and 35, and maxillary alveolar bone volume, osteoblast, and osteoclast volume were determined histomorphometrically on day 35 of OTM. Next, we determined the serum endothelin 1 (ET-1) level and gene expression levels of the osteoclast activity marker cathepsin K and osteoblast activity markers osteocalcin and dentin matrix acidic phosphoprotein 1 (DMP1) on day 35. The ETB-KO appliance group showed significantly lower osteoblast activity, diminished alveolar bone volume and less OTM than the ETB-WT appliance group. Our results showed that ETB is involved in bone modelling in the late stage of OTM.

Effects of Leukocyte-Platelet-Rich Plasma on the Alveolar Bone Changes During Orthodontic Tooth Movement in Rabbits: A Micro-CT Study

Objective: To investigate the effects of leukocyte-platelet-rich plasma (L-PRP) on the alveolar bone changes at the compression and tension sides during orthodontic tooth movement. Materials and Methods: Around 20 New Zealand white rabbits were used in a split-mouth design. The maxillary first premolar was moved mesially with a nickel-titanium closed-coil spring. One side of the maxilla was randomly injected with L-PRP, while the contralateral side served as the control which received normal saline. The alveolar bone adjacent to the maxillary first premolar was scanned using microcomputed tomography at days 0, 7, 14, and 28. Microstructural parameters including bone volume fraction, trabecular thickness, and trabecular separation of alveolar bone were assessed on the compression and tension sides of the maxillary first premolar. Results: Compared between the groups, the L-PPR group showed a significantly decreased bone volume fraction on the compression side on days 7 and 14 but significantly increased bone volume fraction on the tension side on day 14. However, there were no statistically significant differences in the parameters of trabecular thickness and trabecular separation. Conclusion: Local administration of L-PRP may promote bone resorption on the compression side and bone formation on the tension side at the initial stage of orthodontic tooth movement.

Study of bone remodeling in corticotomy-assisted orthodontic tooth movement in rats.

The goal of this study was to determine the structure change of the alveolar bone and the expression of a group of bone remodeling-related factors. Sixty healthy male Wistar rats were randomly divided into three groups. Selective alveolar decortication (SAD), tooth movement (TM), and "combined therapy" (SAD+TM) was performed in group I, II, and III, respectively. On days 0, 7, 14, 21, and 42, a Micro-CT scan was performed on the maxillary alveolar bone and tooth. In addition, on days 0, 7, 14, 21, 28, and 42, some of the rats were killed by cervical dislocation and tissues were harvested. Analysis of scan data revealed a significant decrease in bone density of the alveolar bone at 14 days post-surgery, and increased at 42 days post-surgery to a level higher than that before the surgery. Microarray and bioinformatics analysis were performed to explore gene expression profile in three groups (SAD, TM, and SAD+TM),and a large number of differentially expressed genes were identified. In addition, real-time polymerase chain reaction was performed to determine the expression of bone remodeling-related factors. The expression of osteoblast-related cytokines, including osteopontin, bone sialoprotein, and osteocalcin,and osteoclast regulators macrophage-colony stimulating factor (M-CSF) and RANKL (activator of nuclear factor KB receptor ligand) were increased in group III, suggesting that there was increased bone synthesis and activation of bone absorption. Moreover, group III had a unique alveolar bone remodeling pattern: RANKL and osteoprotegerin-promoted alveolar remodeling. In conclusion, during the early stage of orthodontic tooth movement, corticotomy can accelerate the movement of teeth, modulate the state of bone metabolism, and activate osteogenesis and osteoclast, which support the theory of regional acceleratory phenomenon.

Variations of Salivary Levels of Osteoprotegerin during Orthodontic Tooth Movement

Aim: The study aimed to determine the variations of salivary levels of osteoprotegerin (OPG) during the different stages of orthodontic tooth movement. Materials and Methods: A sample of 24 patients was taken up for the study. Salivary samples were collected from each of the patients at the following intervals: T(0) – before start of the appliance therapy, T(1) – 24–48 h following treatment initiation, T(2) – after 2 weeks of appliance insertion, and T(3) – 5 weeks of appliance insertion. At all times, whole unstimulated salivary samples were collected. ELISA-based assay was used to determine the levels of OPG in the salivary samples. The results were statistically analyzed using ANOVA with Bonferroni t -test. The significance value of P Results: According to the results, there was an insignificant decrease and increase of OPG levels. Salivary levels in the alternate stages of treatment. P value for this particular study was found to be 0.05. Conclusion: The findings indicate that the variations in salivary concentrations of OPG might be linked to various stages of orthodontic tooth movement. The site specificity of OPG collection requires further studies in the long run.

Assessment of Biological markers level in gingival crevicular fluids during early orthodontic treatment of periodontally affected teeth

Background: the aim of the present study was to evaluate the levels of some biological markers; interleukin 1B (IL1B), interleukin 6 (IL6), interleukin 8 (IL8) and prostaglandin(PG) in the gingival crevicular fluids (GCF) in patients with periodontal disease during early stage of orthodontic tooth movement. Subjects and methods: The study included 9 subjects with age range 23-45 years, with periodontally affected teeth submitted to orthodontic treatment at the orthodontic department faculty of dentistry, Al-azhar University,Girls branch. Fixed appliances were inserted, nickel titanium light archwires were used for levelling and alignment. Gingival crevicular fluid (GCF) samples were collected from the healthy and periodontally affected teeth with paper points at base line, 3 days, 1,2,3,4 weeks from starting of orthodontic treatment. Results: during the test period, the levels of IL 6 in healthy teeth and periodontally affected teeth gradually increased after 3 days and 1 week, then gradually decreased after 2 and 3 weeks, Comparing healthy and periodontally affected teeth revealed a higher levels in periodontally affected teeth.. The mean value of IL 8 gradually increased after 3 days and 1 week, then gradually decreased after 2 and 3 weeks. the mean value of IL 1B was gradually increased after 3 days and 1 week, then gradually decreased after 2 and 3 week. PG showed gradual increase after 3 days and 1 week, then gradually decreased after 2, 3 and 4weeks. Comparing healthy and periodontally affected teeth revealed a higher levels in periodontally affected teeth. Conclusion: Our findings suggested that the orthodontic movement of periodontally compromised teeth result in significant changes in the levels of certain biological markers in the GCF as compared to healthy teeth.

Effect of orthodontic tooth movement on salivary levels of Interleukin-1beta, Tumor Necrosis Factor-alpha, and C- reactive protein

Orthodontic force is considered to stimulate cells in the periodontium to release many mediators such as cytokines which play a responsible role for periodontal and alveolar bone remodeling, bone resorption and new bone deposition. Aim of this study was carried out to estimate changes of the (interleukin-one beta, tumor necrosis factor - alpha and C-reactive protein) levels in unstimulated whole saliva during the leveling stage of orthodontic tooth movement. Materials and methods: The sample consisted of thirty adult patients (12 males and 18 females) with ages ranges (19- 23) years. Each sample had Class I and Class II malocclusion dental classification and required bilateral extraction of their maxillary first premolars, underwent a session of professional oral hygiene and received oral hygiene instructions before and during the period of study, one month later fixed orthodontic appliance were placed in the upper arch by using 0.014 nickel titanium arch wire. The unstimulated whole saliva was taken from each sample immediately before placement of the appliance (baseline), and at (after1hour, after one week and after two week) following placement of the fixed orthodontic appliance. In addition the plaque index and gingival index were recorded during the interval periods of this study to assess oral cleanliness. The interleukin - one beta and tumor necrosis factor- alpha were determined by enzyme linked immunosorbent assay, while the C-reactive protein was determined by latex agglutination. Results: The results of the present study found the mean value of both salivary (interleukin-one beta and tumor necrosis factor -alpha) were highest at (after1hour) followed by at (after one week) then at (after two week) than the baseline with highly statistical significant differences (P 0.05). While the mean values of C-reactive protein were higher at (after 1hour) only with highly significant differences (P< 0.01) among females and total samples while only significant difference (P<0.05) for males, in addition there were no statistical significant differences between males and females. Regarding the correlation between salivary (interleukin - one beta and tumor necrosis factor -alpha), there were positive correlation between them at all periods of study. Moreover there were positive correlation between salivary (interleukin - one beta and tumor necrosis factor -alpha) and salivary C- reactive protein. On the other hand there were no association between the salivary (interleukin - one beta and tumor necrosis factor -alpha and C-reactive protein) and clinical parameter (plaque index and gingival index). Conclusion: From this clinical study we conclude that orthodontic force induces increasing the levels of (interleukin - one beta, tumor necrosis factor -alpha, C-reactive protein) in unstimulated whole saliva during orthodontic tooth

Osteocalcin and N-telopeptides of type I collagen marker levels in gingival crevicular fluid during different stages of orthodontic tooth movement

The aim of the study was to quantitatively and qualitatively analyze changes in the gingival crevicular fluid (GCF) during orthodontic movement by assessing the levels of cross-linked N-telopeptides of type I collagen marker (NTx) and osteocalcin (OC) activity. Twenty patients requiring all first premolars to be extracted were selected and treated with conventional straight-wire mechanotherapy. The canines were retracted with closed-coil springs. The maxillary canine on one side acted as the experimental site, and the contralateral canine was the control. GCF was collected from around the canines before retraction, and 1 hour, 1 day, 7 days, 14 days, and 21 days after retraction. GCF NTx and OC levels were estimated and compared with the control side. The results showed statistically significant changes in NTx and OC levels on days 7, 14, and 21 when we compared the experimental and control sides. The peak in all activity of the variables occurred on day 14 after retraction. The study showed that NTx and OC levels can be successfully estimated in the GCF, and its increased levels might indicate the active tooth movement phase in orthodontic therapy.

Immunocompetent cells and cytokine expression in the rat periodontal ligament at the initial stage of orthodontic tooth movement

ObjectiveThe aim of the present study is to investigate the involvement of immunocompetent cells, pro-inflammatory cytokines and HSP, to evaluate a change of periodontal ligament during the initial stage of orthodontic tooth movement. DesignIn the present study, we investigated the distributional density of immunocompetent cells, the localisation of cytokines, and the expression levels of their mRNA in the periodontal ligament during the initial stage of orthodontic tooth movement, using immunohistochemistry and real-time PCR. ResultsOrthodontic tooth movement led to significant recruitment of OX6+ cells and ED1+ cells in the rat PDL. Double-immunofluorescence staining showed that some ED1+ cells expressed pro-inflammatory factors of IL-1β and TNF-α in the PDL during orthodontic tooth movement. Real-time PCR analysis revealed that the expression levels of IL-1β (Il1b) and TNF-α (Tnf) mRNA gradually increased following its decrease after 1h of orthodontic tooth movement. These findings suggest that ED1+ cells are involved in the expression of TNF-α and IL-1β and the subsequent regulation of bone resorption on pressure side. HSP27 (Hspb1) mRNA levels were significantly increased as compared with the control at 1h of the initial stage of treatment. ConclusionED1+ cells involved in the expression of TNF-α and IL-1β may play an important role in the initial reaction of the PDL and in the induction of the osteoclastic bone resorption during orthodontic tooth movement.

The endothelin system mediates bone modeling in the late stage of orthodontic tooth movement in rats

The endothelin system is involved in orthodontic tooth movement (OTM). The aim of the study was to examine the role of ET-1, ET A and ET B in bone modeling during OTM in rats. Male Wistar rats ( n = 62) were divided into three groups: control animals ( n = 10; control group) without appliance, and two groups of experimental animals, which were applied a super-elastic closed-coil spring between the first left maxillary molar and the incisors and were treated daily with either TBC3214 ( n = 10; TBC3214 group) or with saline ( n = 42; appliance only group). TBC3214 is a highly selective antagonist on ET A receptors. The distance between teeth was measured on days 0 and 42. On days 0, 14, 28 and 42 animals of the appliance only group ( n = 8) were sacrificed and tissue samples were taken. Total RNA and protein contents were isolated. Gene expression levels of ET-1, ET A and ET B were assessed by means of relative RT-PCR. Protein levels of ET A and ET B were examined by immunoblotting. Ten animals of each group were sacrificed on day 42 and tissue samples were prepared for histological analysis. Alveolar bone volume, osteoblast and osteoclast volume were determined histomorphometrically. Gene expression levels of ET-1, ET A and ET B varied throughout the experiment and were significantly up-regulated on day 42 ( p < 0.001). The immunoreactivity of ET A and ET B significantly decreased on day 14 ( p < 0.001) and increased on day 28 ( p < 0.001). Alveolar bone volume was significantly higher in the TBC3214 group compared to the appliance only group ( p < 0.001). Osteoclast volume was significantly lower in the TBC3214 group compared to the appliance only group ( p < 0.05). Gene and protein expression levels of ET-1, ET A and ET B varied significantly during OTM, suggesting their different roles in the various stages of OTM. TBC3214 significantly increased alveolar bone volume and significantly decreased osteoclast volume, indicating that it decreased bone resorption in stage three of OTM. These data suggest that ET-1 increases osteoclastic bone resorption via ET A in the late stage of OTM.

Cetirizine, a histamine H1 receptor antagonist, decreases the first stage of orthodontic tooth movement in rats

Cetirizine, a histamine H1 receptor antagonist, decreases the first stage of orthodontic tooth movement in rats

Effects of aging on RANKL and OPG levels in gingival crevicular fluid during orthodontic tooth movement

To compare the levels of the receptor activator of NFkB ligand (RANKL) and osteoprotegerin (OPG) in the gingival crevicular fluid (GCF) during orthodontic tooth movement in juvenile and adult patients. Fifteen juveniles and 15 adults served as subjects. GCF was collected from the distal cervical margins of the experimental and control teeth at 0, 1, 24, and 168 h after application of a retracting force. Enzyme-linked immunosorbent assay kits were used to determine RANKL and OPG levels in the GCF samples. The amount of tooth movement for juveniles was larger than for adults after 168 h. Further, after 24 h RANKL levels were increased and those of OPG decreased in GCF samples from the compression side during orthodontic tooth movement in both juveniles and adults. The RANKL/OPG ratio in GCF from adult patients was lower than that in the juvenile patient samples. Our results suggest that the age-related decrease in amount of tooth movement may be related to a decrease in RANKL/OPG ratio in GCF during the early stages of orthodontic tooth movement.

Does Human Relaxin Accelerate Orthodontic Tooth Movement in Rats?

Human relaxin was administered to young rats through either minipumps (group P) or subcutaneous injections (group I). Control rats received pump implants containing placebo (group C). Day 0 was the day of orthodontic appliance placement and activation to pull bilateral upper first molars forward, and day 14 was the end time point. Cephalometric radiographs (three repeated exposures) were taken at 0, 3, 5, 7, 10, and 14 days. The total length of three maxillary molar segments and the space between the first and second molars were measured under a dissecting microscope postmortem. Both groups P and I showed rapid tooth movement at day 3. Movement slowed, but it still increased gradually in group P while decreasing in group I after that. Concurrent tooth lateral drifts to the buccal side were smaller in both groups P and I. The length and space were larger in both groups P and I. Thus, administration of human relaxin may accelerate the early stages of orthodontic tooth movement in rats.

Expression of cathepsin K mRNA during experimental tooth movement in rat as revealed by in situ hybridization

The expression of cathepsin K, a novel collagenolytic enzyme specifically expressed in osteoclasts, was investigated in the rat maxillary dentoalveolar unit during experimental tooth movement by in situ hybridization histochemistry with a non-radioisotopic cRNA probe for rat cathepsin K. Orthodontic elastics were inserted into the interproximal space between the maxillary first and second molars of 7-week-old male SD rats according to Waldo’s method and sections prepared from tissues obtained at 12 hr, 1, 2, 3, 4, 7, and 12 days after orthodontic force application. Cathepsin K mRNA expression was detected in the mono- and multinuclear osteoclasts on the pressure side of the alveolar bone at 12 hr after force application, and the distribution and number of cathepsin K mRNA-positive osteoclasts increased time-dependently on the pressure side. At 3–4 days, a marked increase in cathepsin K mRNA-positive osteoclasts was found not only on the pressure side but also on the tension side of the alveolar bone in response to tooth movement. At 7–12 days, the cathepsin K mRNA-positive osteoclasts on both sides had disappeared. These findings suggest that the recruitment of osteoclasts on the pressure side begins during the initial stage of orthodontic tooth movement and the site-specific early induction of cathepsin K mRNA may cause an imbalance in the relative resorption activities on the pressure and tension side incident to such movement.

Chemokines are upregulated during orthodontic tooth movement.

In the early stage of orthodontic tooth movement, an acute inflammatory response characterized by the migration of leukocytes occurs. This response suggests the presence of specific chemotactic signals that may play a role in the mechanism of bone remodeling, in particular in resorption. The aim of the present study was to explore the induction of potential chemokines at the resorption side during orthodontic tooth movement. Monocyte chemoattractant protein-1 (MCP-1), regulated on activation normal T cell expressed and secreted (RANTES), and macrophage inflammatory protein-2 (MIP-2) were examined by in situ hybridization using radioactive synthetic oligoneucleotide probes. Mesial movement of the upper first molars was performed with a fixed appliance for 3, 7, and 10 days. The results demonstrated that MCP-1, RANTES, and MIP-2 were highly expressed during orthodontic movement. On day 3, MCP-1 showed maximum induction in the pressure zone, followed in intensity by RANTES and MIP-2, although not in the contralateral control side. The induction of these chemokines had declined on day 7 and reached low levels on day 10. Our data suggest that chemokines are induced early in the application of force, and such induction may contribute to the early inflammatory response that may be responsible in part for the ensuing bone remodeling.