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The Balance between Orthodontic Force and Radiation in the Jawbone: Microstructural, Histological, and Molecular Study in a Rat Model. BIOLOGY 2021; 10:biology10111203. [PMID: 34827196 PMCID: PMC8615105 DOI: 10.3390/biology10111203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/03/2021] [Accepted: 11/10/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary Patients with head and neck cancer are frequently treated by radiation, which results in a lifelong risk of damage (necrosis) to the jawbones. Some of the irradiated young patients at a later time in life may be interested in orthodontic treatment for esthetic or functional purposes. We undertook this study in order to investigate changes that occur in irradiated jawbones when mild orthodontic force is applied in a rat laboratory model. We found that one low dose of radiation had negatively affected the jawbones and that these changes were visible in X-ray images as well as in microscopic slides. The irradiated bones seemed to be denser in the X-rays and had fewer cells that usually regulate normal bone turnover, compared to non-irradiated bones. However, when orthodontic force was applied after radiation, the changes in the irradiated bones were largely, but not completely, reversed in both X-rays and microscopy to the point that bone properties were approaching those of non-irradiated, orthodontically treated, bones. The findings of this study indicate that orthodontic force may have a beneficial effect on the maintenance of jawbone vitality after radiation, but additional studies using different time-lags between radiation and orthodontic force and higher radiation doses are warranted to support these findings. Abstract Irradiation of facial bones is associated with a lifelong risk of osteonecrosis. In a rat model, maxillae were exposed to a single 5 Gy dose of external beam radiation and orthodontic force was applied for 2 weeks on the first maxillary molar; control rats were treated identically without radiation. Tooth movement in irradiated jaws was 30% less than in controls, representing radiation-related damage. Micro-CT, histological, and molecular outcomes of orthodontic tooth movement were studied. Microstructurally, bone parameters (trabecular thickness, bone volume fraction, bone mineral density) were significantly affected by orthodontic force but not by radiation. Histological parameters were influenced only by orthodontic force, especially by an increase in osteoclasts. A molecular study revealed a differential distribution of cells expressing pre-osteoclast markers (RANK+—majority, CD11b+, CD14+—minority), with changes being influenced by orthodontic force (increased CD11b+ and CD14+ cells) and also by radiation (decreased RANK+ cells). The activation status of osteoclasts (TRAP staining) showed an orthodontic-force-related increase, which probably could not fully compensate for the radiation-associated impairment. The overall balance showed that orthodontic force had elicited a substantial microstructural, histological, and functional normalization process in irradiated maxillae but a radiation-induced impact was still conspicuous. Additional studies are needed to validate these findings.
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Dose-related effects of extracorporeal shock waves on orthodontic tooth movement in rabbits. Sci Rep 2021; 11:3405. [PMID: 33564049 PMCID: PMC7873214 DOI: 10.1038/s41598-021-82997-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/27/2021] [Indexed: 01/01/2023] Open
Abstract
The purpose of this animal study is to investigate the quantitative effects of extracorporeal shock waves applied at two different impulses and with two different applicators on orthodontic tooth movement. Thirty-five New Zealand rabbits were randomly divided into five groups (n = 7): the four experimental extracorporeal shock wave groups-focused/500 impulses, focused/1000 impulses, unfocused/500 impulses, and unfocused/1000 impulses-and the control group. Orthodontic tooth movement was achieved by application of reciprocal force between two maxillary incisors. In the experimental groups, animals received 500 or 1000 impulses of extracorporeal shock waves at 0.19 mJ/mm2 with focused or unfocused applicators depending on the group to which they belonged. These experiments were conducted on days 0, 7, and 14. Orthodontic tooth movement was measured with 0.01 mm accuracy at one-week intervals. On days 7 and 21, the bone-specific alkaline phosphatase levels were measured from blood samples. After 21 days, the animals were sacrificed and the area between the two maxillary incisors was stereologically examined. Orthodontic tooth movement in the focused/500 impulses and focused/1000 impulses groups was significantly increased compared to the control group. A significant difference in bone-specific alkaline phosphatase levels between the unfocused/500 impulses and control groups was found at 21st day. Stereological analysis showed that there were significant increases of the formation of new bone, connective tissue, and vessels in the experimental groups. The application of extracorporeal shock waves, especially with a focused applicator, could accelerate orthodontic tooth movement.
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Cheung T, Park J, Lee D, Kim C, Olson J, Javadi S, Lawson G, McCabe J, Moon W, Ting K, Hong C. Ability of mini-implant-facilitated micro-osteoperforations to accelerate tooth movement in rats. Am J Orthod Dentofacial Orthop 2017; 150:958-967. [PMID: 27894545 DOI: 10.1016/j.ajodo.2016.04.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Revised: 04/01/2016] [Accepted: 04/01/2016] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Although current techniques for accelerated tooth movement often involve invasive surgical procedures, micro-osteoperforations (MOPs) using mini-implants may facilitate orthodontic tooth movement without raising flaps, reduce surgical risks, and increase patient acceptance. In this study, we evaluated the effectiveness of mini-implant-facilitated MOPs in inducing accelerated tooth movement and investigated the potential risks for root resorption. METHODS Five MOPs were placed on the left side around the maxillary first molars in 6 rats using an automated mini-implant driver, whereas the right side received no MOPs as the control. Closed-coiled springs were secured from incisors to first molars for orthodontic tooth movement. Tooth movement was measured, and samples underwent radiologic and histologic analyses. RESULTS The MOP side exhibited a 1.86-fold increase in the rate of tooth movement with decreased bone density and bone volume around the first molars compared with the control side. Hematoxylin and eosin and tartrate-resistant acid phosphatase analyses showed increased numbers of osteoclasts as well as new bone formation. Three-dimensional volumetric analysis of all 5 roots of the maxillary first molars demonstrated no statistically significant difference in root volumes. CONCLUSIONS Mini-implant-facilitated MOPs accelerated tooth movement without increased risk for root resorption and therefore may become a readily available and efficient treatment option to shorten orthodontic treatment time with improved patient acceptance.
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Affiliation(s)
- Tracy Cheung
- Resident, Section of Orthodontics, School of Dentistry, University of California at Los Angeles, Los Angeles, Calif
| | - Juyoung Park
- Graduate student, Division of Oral Biology, University of California at Los Angeles, Los Angeles, Calif
| | - Deborah Lee
- Graduate student, School of Dentistry, University of California at Los Angeles, Los Angeles, Calif
| | - Catherine Kim
- Graduate student, School of Dentistry, University of California at Los Angeles, Los Angeles, Calif
| | - Jeffrey Olson
- Graduate student, School of Dentistry, University of California at Los Angeles, Los Angeles, Calif
| | - Shadi Javadi
- Assistant project scientist, Section of Orthodontics, School of Dentistry, University of California at Los Angeles, Los Angeles, Calif
| | - Gregory Lawson
- Director, Pathology and Laboratory Medicine, Division of Laboratory Animal Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, Calif
| | - James McCabe
- Training manager, Division of Laboratory Animal Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, Calif
| | - Won Moon
- Clinical associate professor, Section of Orthodontics, School of Dentistry, University of California at Los Angeles, Los Angeles, Calif
| | - Kang Ting
- Chair and professor, Section of Orthodontics, School of Dentistry, University of California at Los Angeles, Los Angeles, Calif
| | - Christine Hong
- Assistant professor, Section of Orthodontics, School of Dentistry, University of California at Los Angeles, Los Angeles, Calif.
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Sella RC, Mendonça MRD, Cuoghi OA, An TL. Histomorphometric evaluation of periodontal compression and tension sides during orthodontic tooth movement in rats. Dental Press J Orthod 2012. [DOI: 10.1590/s2176-94512012000300021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Xie R, Kuijpers-Jagtman AM, Maltha JC. Osteoclast differentiation and recruitment during early stages of experimental tooth movement in rats. Eur J Oral Sci 2009; 117:43-50. [DOI: 10.1111/j.1600-0722.2008.00588.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Xie R, Kuijpers-Jagtman AM, Maltha JC. Osteoclast differentiation during experimental tooth movement by a short-term force application: an immunohistochemical study in rats. Acta Odontol Scand 2008; 66:314-20. [PMID: 18720051 DOI: 10.1080/00016350802317488] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVE The origin of osteoclasts responsible for bone resorption during orthodontic tooth movement is not yet clear. Their precursors may reside within the periodontal ligament (PDL) or could be recruited from the circulation or the bone marrow. The aim of this study was to investigate the spatial and sequential distribution of osteoclast precursors during experimental tooth movement by using three differentiation markers: receptor for macrophage colony stimulating factor (c-Fms), receptor activator of nuclear factor-kappaB (RANK), and calcitonin receptor (CTR). MATERIAL AND METHODS Six-week-old Wistar rats were used. Elastic bands were inserted between the upper 1st and 2nd molars for 1, 2, 3, and 6 days. Immunohistochemical staining for c-Fms, RANK, or CTR was performed on parasagittal sections and positive cells were counted. RESULTS Before force application, many c-Fms+ and a few RANK+ precursors were present in the bone marrow. No c-Fms+ osteoclast precursors were observed in the PDL. After force application, the number of RANK+ but not c-Fms+ precursors increased rapidly in the PDL. In bone marrow, the number of c-Fms+ and RANK+ precursors also increased rapidly, as did multinuclear c-Fms+, RANK+, and CTR+ cells. Subsequently, the number of c-Fms+, RANK+, and CTR+ multinuclear cells in the PDL increased. After 6 days, the expression profiles tended to return to baseline levels. CONCLUSION Osteoclast precursors differentiate within the bone marrow and then migrate into the PDL during early tooth movement.
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Hosokawa Y, Sakakura Y, Tanaka L, Okumura K, Yajima T, Kaneko M. Effects of local and whole body irradiation on appearance of osteoclasts during wound healing of tooth extraction sockets in rats. JOURNAL OF RADIATION RESEARCH 2007; 48:273-80. [PMID: 17538234 DOI: 10.1269/jrr.06069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We examined effects of local and whole body irradiation before tooth extraction on appearance and differentiation of osteoclasts in the alveolar bone of rat maxillary first molars. Wistar rats weighting 100 g were divided into three groups: non-irradiation group, local irradiation group, and whole body irradiation group. In the local irradiation group, a field made with lead blocks was placed over the maxillary left first molar tooth. In the whole body irradiation group, the animals were irradiated in cages. Both groups were irradiated at 8 Gy. The number of osteoclasts around the interradicular alveolar bone showed chronological changes common to non-irradiated and irradiated animals. Several osteoclasts appeared one day after tooth extraction, and the maximal peak was observed 3 days after extraction. Local irradiation had no difference from non-irradiated controls. In animals receiving whole body irradiation, tooth extraction one day after irradiation caused smaller number of osteoclasts than that 7 day after irradiation during the experimental period. Whole body-irradiated rats had small osteoclasts with only a few nuclei and narrow resorption lacunae, indicating deficiency of radioresistant osteoclast precursor cells. Injection of intact bone marrow cells to whole body-irradiated animals immediately after tooth extraction recovered to some content the number of osteoclasts. These findings suggest that bone resorption in the wound healing of alveolar socket requires radioresistant, postmitotic osteoclast precursor cells from hematopoietic organs, but not from local sources around the alveolar socket, at the initial phase of wound healing.
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Affiliation(s)
- Yoichiro Hosokawa
- Department of Dental Radiology, School of Dentistry, Health Sciences University of Hokkaido, Kanazawa, Hokkaido.
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Tomizuka R, Shimizu Y, Kanetaka H, Suzuki A, Urayama S, Kikuchi M, Mitani H, Igarashi K. Histological Evaluation of the Effects of Initially Light and Gradually Increasing Force on Orthodontic Tooth Movement. Angle Orthod 2007; 77:410-6. [PMID: 17465646 DOI: 10.2319/0003-3219(2007)077[0410:heoteo]2.0.co;2] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Accepted: 07/01/2006] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE To investigate histologically the effect of initially light and gradually increasing force on tooth movement in the rat. MATERIALS AND METHODS Cuboids made of neodymium-iron-boron magnets (experimental groups) or titanium (control group) were bonded to the lingual surface of the right and left maxillary first molars of 18-week-old male Wistar rats. The initial distances between materials were 1.0 mm generating 4.96 gf (experimental group 1) and 1.5 mm generating 2.26 gf (experimental group 2). In three groups, rats were killed 1, 3, 7, 10, or 14 days after treatment. Histological sections were prepared and stained with hematoxylin and eosin or for tartrate-resistant acid phosphatase (TRAP) activity. The number of TRAP-positive osteoclasts was counted, and the relative hyalinized area was measured on the pressure side of periodontal ligament. RESULTS There were significant differences in the number of osteoclasts among the three groups (P < .05). On days 1 and 3, the numbers of osteoclasts in experimental group 2 were greater than in experimental group 1. There were significant differences in the relative hyalinized area between the control group and experimental group 1 (P < .01) and between experimental groups 1 and 2 (P < .01). On days 1 and 3, the hyalinized area in experimental group 1 was larger than in experimental group 2. CONCLUSION Initially light and gradually increasing force induced tooth movement without the lag phase and showed smooth recruitment of osteoclasts and inhibition of hyalinization.
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Affiliation(s)
- Ryo Tomizuka
- Division of Orthodontics and Dentofacial Orthopedics, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Miyagi, Japan.
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Krishnan V, Davidovitch Z. Cellular, molecular, and tissue-level reactions to orthodontic force. Am J Orthod Dentofacial Orthop 2006; 129:469.e1-32. [PMID: 16627171 DOI: 10.1016/j.ajodo.2005.10.007] [Citation(s) in RCA: 557] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2005] [Revised: 08/13/2005] [Accepted: 10/14/2005] [Indexed: 12/17/2022]
Abstract
Remodeling changes in paradental tissues are considered essential in effecting orthodontic tooth movement. The force-induced tissue strain produces local alterations in vascularity, as well as cellular and extracellular matrix reorganization, leading to the synthesis and release of various neurotransmitters, cytokines, growth factors, colony-stimulating factors, and metabolites of arachidonic acid. Recent research in the biological basis of tooth movement has provided detailed insight into molecular, cellular, and tissue-level reactions to orthodontic forces. Although many studies have been reported in the orthodontic and related scientific literature, a concise convergence of all data is still lacking. Such an amalgamation of the rapidly accumulating scientific information should help orthodontic clinicians and educators understand the biological processes that underlie the phenomenon of tooth movement with mechanics (removable, fixed, or functional appliances). This review aims to achieve this goal and is organized to include all major findings from the beginning of research in the biology of tooth movement. It highlights recent developments in cellular, molecular, tissue, and genetic reactions in response to orthodontic force application. It reviews briefly the processes of bone, periodontal ligament, and gingival remodeling in response to orthodontic force. This review also provides insight into the biological background of various deleterious effects of orthodontic forces.
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Affiliation(s)
- Vinod Krishnan
- Department of Orthodontics, Rajas Dental College, Tirunelveli District, Tamilnadu, India.
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Ohno Y, Yamada Y, Usu T, Takahashi K, Tsuchiya F, Ohtani H, Sato H, Sawada Y, Iga T. Pharmacokinetic and pharmacodynamic analysis of the antihypercalcemic effect of incadronate disodium in rats. Biol Pharm Bull 2001; 24:1290-3. [PMID: 11725966 DOI: 10.1248/bpb.24.1290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Incadronate concentrates into the bone as a target organ after intravenous administration of incadronate disodium. Mature osteoclasts has take up incadronate from the bone surface and convert it from an active to an inactive form. As a result, incadronate decreases the plasma calcium concentration by suppressing bone resorption. In this study, the pharmacokinetic and pharmacodynamic (PK/PD) analysis model for ascertaining the antihypercalcemic effects of incadronate disodium was developed in rats. Data on both the concentration of incadronate in bone and that of free calcium in blood after intravenous administration from our previous study were used for analysis. To estimate the concentration in the surface layer of bone, data on the concentration of incadronate in bone after single intravenous administration were analyzed based on the PK model considering three-compartments. The estimated concentrations in the surface layer in bone were applied to the PD model as an input function. The PD model was developed to analyze the changes in the plasma calcium concentration after a single intravenous administration considering an irreversible inhibition of osteoclast activity. The obtained fitted curves were in good agreement with the observed data. The model could explain the long duration of the antihypercalcemic effect of incadronate disodium and should be useful for planning rational dose regimens for effective antihypercalcemic therapy.
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Affiliation(s)
- Y Ohno
- Department of Pharmacy, University of Tokyo Hospital, Faculty of Medicine, University of Tokyo, Japan
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Rody WJ, King GJ, Gu G. Osteoclast recruitment to sites of compression in orthodontic tooth movement. Am J Orthod Dentofacial Orthop 2001; 120:477-89. [PMID: 11709665 DOI: 10.1067/mod.2001.118623] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although it is widely acknowledged that osteoclasts are formed by the fusion of mononuclear cells of hematopoietic origin, it has been extremely difficult to understand how they originate after appliance activation. The purpose of this study was to quantify osteoclast recruitment at compression sites as a function of time following orthodontic force application. Appliances were placed in 96 rats. At day 0, the animals were randomized to either appliance activation or sham activation followed by the injection of 5-bromo-2'-deoxyuridine (BrdU). Thus, BrdU was incorporated into the nuclei of cells in S-phase, including hematopoietic stem cells. Groups of 10 to 13 rats were killed at 1, 3, 5, and 7 days after activation/sham, and the tissue samples were prepared. The numbers of BrdU-labeled cells positively stained with tartrate-resistant acid phosphatase (TRAP) were measured in the periodontium. A significant number of BrdU-positive preosteoclasts was observed in the periodontal ligament (PDL) and bone surface at day 3. The number of osteoclastic cells in the bone marrow also peaked at day 3; however, the highest percentage of cells in this location was observed at day 1. These data suggest that osteoclasts in the PDL originate by the fusion of recently recruited preosteoclasts from the marrow instead of from local PDL cells. Furthermore, the alveolar bone marrow plays a role in the formation of osteoclasts during orthodontic tooth movement.
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Affiliation(s)
- W J Rody
- School of Dentistry, University of Washington, Seattle, USA
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