scholarly journals A Novel Method to Quantify Longitudinal Orthodontic Bone Changes with In Vivo Micro-CT Data

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Chao Wang ◽  
Li Cao ◽  
Chongshi Yang ◽  
Yubo Fan

Orthodontic tooth movement (OTM) is the result of region-specific bone modeling under a load. Quantification of this change in the alveolar bone around a tooth is a basic requirement to understand the mechanism of orthodontics. The purpose of this study was to quantify subregional alveolar bone changes during orthodontic tooth movement with a novel method. In this study, 12 Sprague-Dawley (SD) rats were used as an orthodontic model, and one side of the first upper molar was used to simulate OTM. The alveolar bone around the mesial root was reconstructed from in vivo micro-CT images and separated from other parts of the alveolar bone with two semicylinder filters. The amount and rate of OTM, bone mineral density (BMD), and bone volume (BV) around the root were calculated and compared at 5 time points. The results showed that the amount of tooth movement, BMD, and BV can be evaluated dynamically with this method. The molar moved fastest during the first 3 days, and the rate decreased after day 14. BMD decreased from day 0 to day 14 and returned from day 14 to day 28. BV deceased from day 0 to day 7 and from day 14 to day 28. The method created in this study can be used to accurately quantify dynamic alveolar bone changes during OTM.

2015 ◽  
Vol 86 (4) ◽  
pp. 558-564 ◽  
Author(s):  
Chi-Yang Tsai ◽  
Teng-Kai Yang ◽  
Hsueh-Yin Hsieh ◽  
Liang-Yu Yang

ABSTRACT Objective:  To investigate the effects of flapless micro-osteoperforation and corticision on the rate of orthodontic tooth movement in rats. Materials and Methods:  Forty-five 8-week-old male Sprague-Dawley rats were divided into the following groups: micro-osteoperforation and orthodontic force (MOP + F), corticision and orthodontic force (C + F), and orthodontic force only (F, control). The left maxillary first molars were pulled forward with a force of 50 g. Flapless surgical interventions were conducted in the MOP + F and C + F groups. The total duration of the experiment was 6 weeks. Alveolar bone density and the number of osteoclasts were evaluated using microcomputed tomography and histologic examination, respectively. Results:  The tooth movement distance was significantly higher in both experimental groups than in the control group. Bone density and bone mineral density decreased in the MOP + F and C + F groups. The number of osteoclasts in the MOP + F and C + F groups was significantly higher than in the control group F. Conclusion:  The two minimally invasive flapless surgical interventions increased bone remodeling and osteoclast activity and induced faster orthodontic tooth movement for at least 2 weeks in rats. No differences were observed between the outcome of flapless micro-osteoperforation and corticision in the rats.


Author(s):  
Birgit Rath-Deschner ◽  
Andressa V. B. Nogueira ◽  
Svenja Beisel-Memmert ◽  
Marjan Nokhbehsaim ◽  
Sigrun Eick ◽  
...  

Abstract Objectives The aim of this in vitro and in vivo study was to investigate the interaction of periodontitis and orthodontic tooth movement on interleukin (IL)-6 and C-X-C motif chemokine 2 (CXCL2). Materials and methods The effect of periodontitis and/or orthodontic tooth movement (OTM) on alveolar bone and gingival IL-6 and CXCL2 expressions was studied in rats by histology and RT-PCR, respectively. The animals were assigned to four groups (control, periodontitis, OTM, and combination of periodontitis and OTM). The IL-6 and CXCL2 levels were also studied in human gingival biopsies from periodontally healthy and periodontitis subjects by RT-PCR and immunohistochemistry. Additionally, the synthesis of IL-6 and CXCL2 in response to the periodontopathogen Fusobacterium nucleatum and/or mechanical strain was studied in periodontal fibroblasts by RT-PCR and ELISA. Results Periodontitis caused an increase in gingival levels of IL-6 and CXCL2 in the animal model. Moreover, orthodontic tooth movement further enhanced the bacteria-induced periodontal destruction and gingival IL-6 gene expression. Elevated IL-6 and CXCL2 gingival levels were also found in human periodontitis. Furthermore, mechanical strain increased the stimulatory effect of F. nucleatum on IL-6 protein in vitro. Conclusions Our study suggests that orthodontic tooth movement can enhance bacteria-induced periodontal inflammation and thus destruction and that IL-6 may play a pivotal role in this process. Clinical relevance Orthodontic tooth movement should only be performed after periodontal therapy. In case of periodontitis relapse, orthodontic therapy should be suspended until the periodontal inflammation has been successfully treated and thus the periodontal disease is controlled again.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jing Wang ◽  
Delong Jiao ◽  
Xiaofeng Huang ◽  
Yuxing Bai

Abstract Background During orthodontic tooth movement (OTM), alveolar bone remodelling is closely related to mechanical force. It is unclear whether stem cells can affect osteoclastogenesis to promote OTM. This study aimed to investigate the role of mouse bone marrow mesenchymal stem cells (mBMMSCs) under compression load in OTM. Methods A mouse OTM model was established, and GFP-labelled mBMMSCs and normal saline were injected into different groups of mice by tail vein injection. OTM distance was measured using tissue specimens and micro-computed tomography (micro-CT). The locations of mBMMSCs were traced using GFP immunohistochemistry. Haematoxylin-eosin staining, tartrate-resistant acid phosphate (TRAP) staining and immunohistochemistry of Runx2 and lipoprotein lipase were used to assess changes in the periodontal ligament during OTM. mBMMSCs under compression were co-cultured with mouse bone marrow-derived macrophages (mBMMs), and the gene expression levels of Rankl, Mmp-9, TRAP, Ctsk, Alp, Runx2, Ocn and Osterix were determined by RT-PCR. Results Ten days after mBMMSCs were injected into the tail vein of mice, the OTM distance increased from 176 (normal saline) to 298.4 μm, as determined by tissue specimen observation, and 174.2 to 302.6 μm, as determined by micro-CT metrological analysis. GFP-labelled mBMMSCs were mostly located on the compressed side of the periodontal ligament. Compared to the saline group, the number of osteoclasts in the alveolar bone increased significantly (P < 0.01) on the compressed side in the mBMMSC group. Three days after mBMMSC injection, the number of Runx2-GFP double-positive cells on the tension side was significantly higher than that on the compression side. After applying compressive force on the mBMMSCs in vitro for 2 days, RANKL expression was significantly higher than in the non-compression cells, but expression of Alp, Runx2, Ocn and Osterix was significantly decreased (P < 0.05). The numbers of osteoclasts differentiated in response to mBMMs co-cultured with mBMMSCs under pressure load and expression of osteoclast differentiation marker genes (Mmp-9, TRAP and Ctsk) were significantly higher than those in mBMMs stimulated by M-CSF alone (P < 0.05). Conclusions mBMMSCs are not only recruited to the compressed side of the periodontal ligament but can also promote osteoclastogenesis by expressing Rankl, improving the efficiency of OTM.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Neelambar Kaipatur ◽  
Yuchin Wu ◽  
Samer Adeeb ◽  
Thomas Stevenson ◽  
Paul Major ◽  
...  

The aim of this animal study was to develop a model of orthodontic tooth movement using a microimplant as a TSAD in rodents. A finite element model of the TSAD in alveolar bone was built usingμCT images of rat maxilla to determine the von Mises stresses and displacement in the alveolar bone surrounding the TSAD. Forin vivovalidation of the FE model, Sprague-Dawley rats (n=25) were used and a Stryker 1.2 × 3 mm microimplant was inserted in the right maxilla and used to protract the right first permanent molar using a NiTi closed coil spring. Tooth movement measurements were taken at baseline, 4 and 8 weeks. At 8 weeks, animals were euthanized and tissues were analyzed by histology and EPMA. FE modeling showed maximum von Mises stress of 45 Mpa near the apex of TSAD but the average von Mises stress was under 25 Mpa. Appreciable tooth movement of 0.62 ± 0.04 mm at 4 weeks and 1.99 ± 0.14 mm at 8 weeks was obtained. Histological and EPMA results demonstrated no active bone remodeling around the TSAD at 8 weeks depicting good secondary stability. This study provided evidence that protracted tooth movement is achieved in small animals using TSADs.


2012 ◽  
Vol 83 (3) ◽  
pp. 402-409 ◽  
Author(s):  
Nan Ru ◽  
Sean Shih-Yao Liu ◽  
Li Zhuang ◽  
Song Li ◽  
Yuxing Bai

ABSTRACT Objective: To observe the real-time microarchitecture changes of the alveolar bone and root resorption during orthodontic treatment. Materials and Methods: A 10 g force was delivered to move the maxillary left first molars mesially in twenty 10-week-old rats for 14 days. The first molar and adjacent alveolar bone were scanned using in vivo microcomputed tomography at the following time points: days 0, 3, 7, and 14. Microarchitecture parameters, including bone volume fraction, structure model index, trabecular thickness, trabecular number, and trabecular separation of alveolar bone, were measured on the compression and tension side. The total root volume was measured, and the resorption crater volume at each time point was calculated. Univariate repeated measures analysis of variance with Bonferroni corrections were performed to compare the differences in each parameter between time points with significance level at P &lt; .05. Results: From day 3 to day 7, bone volume fraction, structure model index, trabecular thickness, and trabecular separation decreased significantly on the compression side, but the same parameters increased significantly on the tension side from day 7 to day 14. Root resorption volume of the mesial root increased significantly on day 7 of orthodontic loading. Conclusions: Real-time root and bone resorption during orthodontic movement can be observed in 3 dimensions using in vivo micro-CT. Alveolar bone resorption and root resorption were observed mostly in the apical third on day 7 on the compression side; bone formation was observed on day 14 on the tension side during orthodontic tooth movement.


2021 ◽  
Vol 22 (15) ◽  
pp. 8225
Author(s):  
Ko Eun Lee ◽  
Mijeong Jeon ◽  
Seunghan Mo ◽  
Hyo-Seol Lee ◽  
Je Seon Song ◽  
...  

Replacement and inflammatory resorption are serious complications associated with the delayed replantation of avulsed teeth. In this study, we aimed to assess whether deferoxamine (DFO) can suppress inflammation and osteoclastogenesis in vitro and attenuate inflammation and bone resorption in a replanted rat tooth model. Cell viability and inflammation were evaluated in RAW264.7 cells. Osteoclastogenesis was confirmed by tartrate-resistant acid phosphatase staining, reactive oxygen species (ROS) measurement, and quantitative reverse transcriptase–polymerase chain reaction in teeth exposed to different concentrations of DFO. In vivo, molars of 31 six-week-old male Sprague–Dawley rats were extracted and stored in saline (n = 10) or DFO solution (n = 21) before replantation. Micro-computed tomography (micro-CT) imaging and histological analysis were performed to evaluate inflammation and root and alveolar bone resorption. DFO downregulated the genes related to inflammation and osteoclastogenesis. DFO also reduced ROS production and regulated specific pathways. Furthermore, the results of the micro-CT and histological analyses provided evidence of the decrease in inflammation and hard tissue resorption in the DFO group. Overall, these results suggest that DFO reduces inflammation and osteoclastogenesis in a tooth replantation model, and thus, it has to be further investigated as a root surface treatment option for an avulsed tooth.


2021 ◽  
Author(s):  
Xun Xi ◽  
Zixuan Li ◽  
Yi Zhao ◽  
Hong Liu ◽  
Shuai Chen ◽  
...  

Abstract Background Biomechanical forces are vital for the regulation of skeletal tissue. Mechanical stretch plays a vital role in osteogenic differentiation of periodontal ligament stem cells (PDLSCs) during orthodontic treatment. Cyclic mechanical stretch may trigger the up-regulated production of reactive oxygen species (ROS). ROS has a critical effect on bone cell function and the pathophysiology of bone diseases. N-acetylcysteine (NAC), a ROS scavenger, possesses powerful antioxidant capacity. The aim of this study was to determine the role of ROS and NAC in PDLSCs during osteogenic differentiation under cyclic mechanical stretch. We further investigated that the therapeutic potential of NAC to improve the changes of the microstructure of alveolar bone during orthodontic tooth movement in rats by micro-CT system. Methods The expression of COL1 (collagen type I), RUNX2 (runt-related transcription factor 2) and OPN (osteopontin) by qRT-PCR and Western blot experiments, and alkaline phosphatase (ALP) staining as well as ALP activity tests were used to examine osteogenic differentiation tendency of PDLSCs subjected to cyclic mechanical stretch of 10% and 0.5Hz deformation induced by the Flexcell tension system. ROS production in PDLSCs were measured under cyclic mechanical stretch by Flow Cytometry. The levels of reduced glutathione (GSH), oxidized GSH (GSSG) and the GSH/GSSG ratio with or without NAC treatment were analyzed. And we evaluated the changes of the microstructure of alveolar bone during orthodontic tooth movement in rats employing micro-CT system. Results NAC treatment could promote the osteogenic differentiation of PDLSCs under cyclic mechanical stretch. Down-regulated ROS generation and the up-regulated level of GSH and the ratio of GSH/GSSG in PDLSCs treated with NAC were observed in response to cyclic mechanical stretch. NAC improved the microstructure of alveolar bone, including BV/TV (bone volume/total volume), Tb.Th (trabecular thickness), Tb.Sp (trabecular separation) and SMI (microstructure model index), during orthodontic tooth movement in rats. Conclusion These results revealed that NAC might be a potential therapeutic approach for the remodeling of the alveolar bone during orthodontic tooth movement.


2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Fumitoshi Ohori ◽  
Hideki Kitaura ◽  
Aseel Marahleh ◽  
Akiko Kishikawa ◽  
Saika Ogawa ◽  
...  

Osteocytes are abundant cells in bone, which contribute to bone maintenance. Osteocytes express receptor activator of nuclear factor kappa-B ligand (RANKL) and regulate osteoclast formation. Orthodontic tooth movement (OTM) occurs by osteoclast resorption of alveolar bone. Osteocyte-derived RANKL is critical in bone resorption during OTM. Additionally, tumor necrosis factor-α (TNF-α) is important in osteoclastogenesis during OTM. Sclerostin has been reported to enhance RANKL expression in the MLO-Y4 osteocyte-like cell line. This study investigated the effect of TNF-α on sclerostin expression in osteocytes during OTM. In vitro analysis of primary osteocytes, which were isolated from DMP1-Topaz mice by sorting the Topaz variant of GFP-positive cells, revealed that SOST mRNA expression was increased when osteocytes were cultured with TNF-α and that RANKL mRNA expression was increased when osteocytes were cultured with sclerostin. Moreover, the number of TRAP-positive cells was increased in osteocytes and osteoclast precursors cocultured with sclerostin. In vivo analysis of mouse calvariae that had been subcutaneously injected with phosphate-buffered saline (PBS) or TNF-α revealed that the number of TRAP-positive cells and the percentage of sclerostin-positive osteocytes were higher in the TNF-α group than in the PBS group. Furthermore, the level of SOST mRNA was increased by TNF-α. As an OTM model, a Ni-Ti closed-coil spring connecting the upper incisors and upper-left first molar was placed to move the first molar to the mesial direction in wild-type (WT) mice and TNF receptor 1- and 2-deficient (TNFRsKO) mice. After 6 days of OTM, the percentage of sclerostin-positive osteocytes on the compression side of the first molar in TNFRsKO mice was lower than that in WT mice. In this study, TNF-α increased sclerostin expression in osteocytes, and sclerostin enhanced RANKL expression in osteocytes. Thus, TNF-α may play an important role in sclerostin expression in osteocytes and enhance osteoclast formation during OTM.


2019 ◽  
Vol 53 (4) ◽  
pp. 264-271
Author(s):  
Theerasak Nakornnoi ◽  
Chidchanok Leethanakul ◽  
Bancha Samruajbenjakun

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.


2021 ◽  
pp. 002203452110215
Author(s):  
A. Jin ◽  
Y. Hong ◽  
Y. Yang ◽  
H. Xu ◽  
X. Huang ◽  
...  

The high prevalence of malocclusion and dentofacial malformations means that the demand for orthodontic treatments has been increasing rapidly. As the biological basis of orthodontic treatment, the mechanism of mechanical force–induced alveolar bone remodeling during orthodontic tooth movement (OTM) has become the key scientific issue of orthodontics. It has been demonstrated that bone mesenchymal stem cells (BMSCs) are crucial for bone remodeling and exhibit mechanical sensing properties. Mechanical force can promote osteoblastic differentiation of BMSCs and osteogenesis, but the key factor that mediates mechanical force–induced osteogenesis during OTM remains unclear. In this study, by performing reverse-phase protein arrays on BMSCs exposed to mechanical force, we found that the expression level of forkhead box O3 (FOXO3) was significantly upregulated during the mechanical force–induced osteoblastic differentiation of BMSCs. The number of FOXO3-positive cells was consistently higher on the OTM side as compared with the control side and accompanied by the enhancement of osteogenesis. Remarkably, inhibiting FOXO3 with repaglinide delayed OTM by severely impairing mechanical force–induced bone formation in vivo. Moreover, knockdown of FOXO3 effectively inhibited the mechanical force–induced osteoblastic differentiation of BMSCs, whereas the overexpression of FOXO3 enhanced this effect. Mechanistically, we revealed a novel regulatory model in which FOXO3 promoted osteocalcin transcription by activating its promoter in cooperation with runt-related transcription factor 2 (RUNX2). We collectively obtained the first evidence that FOXO3 is critical for OTM, where it responds to mechanical force and directly regulates downstream osteoblastic differentiation in an efficient manner.


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