acid-phosphatase and Root-Resorption

Interleukin-4 (IL-4) is a recognized immunomodulatory cytokine that regulates bone homeostasis. However, the influence of IL-4 on orthodontic tooth movement (OTM) and subsequent root resorption is still unknown. Therefore, the purpose of this study was to investigate the effect of IL-4 on tooth movement and its associated root resorption in a mouse model.. The maxillary first molars of four male mice for each experimental group were subjected to mesial force by a nickel titanium coil spring for 12 days. Control mice were not given appliances and injections. Varying doses of IL-4 were injected locally, adjacent to the first molar. Two sets of experiments were designed. The first set was composed of three groups: the control, treatment with phosphate-buffered saline (PBS), or 1.5 µg/day of IL-4. The second set was composed of five groups: the control, treatment with 0 (PBS only), 0.015, 0.15, or 1.5 µg/day of IL-4. The distance of OTM was measured and tartrate-resistant acid phosphatase positive cells along the loaded alveolar bone and root surface were identified. The root resorption associated with OTM was evaluated by a scanning electron microscope.. The amount of OTM and the number of osteoclasts were significantly decreased in the IL-4-treated mice. Moreover, IL-4 significantly suppressed force-induced odontoclasts and root resorption.. IL-4 inhibits tooth movement and prevents root resorption in the mouse model. These results suggest that IL-4 could be used as a useful adjunct to regulate the extent of OTM and also to control root resorption.

Topics: Acid Phosphatase; Alveolar Process; Animals; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Interleukin-4; Isoenzymes; Male; Mice, Inbred C57BL; Molar; Osteoclasts; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tooth Movement Techniques; Tooth Root; Weight-Bearing

Mechanical force-induced orthodontic root resorption is a major clinical challenge in orthodontic treatment. Macrophages play an important role in orthodontic root resorption, but the underlying mechanism remains unclear. In this study, we examined the mechanism by which the ratio of M1 to M2 macrophage polarization affects root resorption during orthodontic tooth movement. Root resorption occurred when nickel-titanium coil springs were applied on the upper first molars of rats for 3 to 14 d. Positively stained odontoclasts or osteoclasts with tartrate-resistant acid phosphatase were found in resorption areas. Meanwhile, M1-like macrophages positive for CD68 and inducible nitric oxide synthase (iNOS) persistently accumulated on the compression side of periodontal tissues. In addition, the expressions of the M1 activator interferon-γ and the M1-associated pro-inflammatory cytokine tumor necrosis factor (TNF)-α were upregulated on the compression side of periodontal tissues. When the coil springs were removed at the 14th day after orthodontic force application, root resorption was partially rescued. The number of CD68(+)CD163(+) M2-like macrophages gradually increased on the compression side of periodontal tissues. The levels of M2 activator interleukin (IL)-4 and the M2-associated anti-inflammatory cytokine IL-10 also increased. Systemic injection of the TNF-α inhibitor etanercept or IL-4 attenuated the severity of root resorption and decreased the ratio of M1 to M2 macrophages. These data imply that the balance between M1 and M2 macrophages affects orthodontic root resorption. Root resorption was aggravated by an enhanced M1/M2 ratio but was partially rescued by a reduced M1/M2 ratio.

Topics: Acid Phosphatase; Animals; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Biomarkers; Biomechanical Phenomena; Cell Culture Techniques; Etanercept; Humans; Immunoglobulin G; Immunologic Factors; Interferon-gamma; Interleukin-10; Interleukin-4; Isoenzymes; Macrophage Activation; Macrophages; Male; Molar; Nitric Oxide Synthase Type II; Orthodontic Wires; Osteoclasts; Periodontal Ligament; Rats; Rats, Sprague-Dawley; Receptors, Cell Surface; Receptors, Scavenger; Receptors, Tumor Necrosis Factor; Root Resorption; Tartrate-Resistant Acid Phosphatase; Time Factors; Tooth Movement Techniques; Tumor Necrosis Factor-alpha

In this study, we first investigated the expressions of Jagged1, Notch2, the receptor activator of nuclear factor-kappa B ligand (RANKL), and interleukin (IL)-6 in areas of root resorption during experimental tooth movement in rats in vivo. We then assessed the effects of compression force (CF) with or without GSI (an inhibitor of Notch signaling) on Jagged1, RANKL, and IL-6 release from human periodontal ligament (hPDL) cells. Twelve male 6-wk-old Wistar rats were subjected to an orthodontic force of 50 g to induce mesially tipping movement of the upper first molars for 7 d. The expression levels of tartrate-resistant acid phosphatase, Jagged1, Notch2, IL-6, and RANKL proteins in the dental root were determined using an immunohistochemical analysis. Furthermore, the effects of the CF on Jagged1, IL-6, and RANKL production were investigated using hPDL cells in vitro. The effects of the cell-conditioned medium obtained from the hPDL cells subjected to CF (CFM) and Jagged 1 on osteoclastogenesis of human osteoclast precursor cells (hOCPs) were also investigated. Under the conditions of experimental tooth movement in vivo, resorption lacunae with multinucleated cells were observed in the 50 g group. In addition, immunoreactivity for Jagged1, Notch2, IL-6, and RANKL was detected on day 7 in the PDL tissue subjected to the orthodontic force. In the in vitro study, the compression force increased the production of Jagged1, IL-6, and RANKL from the hPDL cells, whereas treatment with GSI inhibited the production of these factors in vitro. The osteoclastogenesis increased with the CFM and rhJagged1, and the increase in the osteoclastogenesis was almost inhibited by GSI. These results suggest that the Notch signaling response to excessive orthodontic forces stimulates the process of root resorption via RANKL and IL-6 production from hPDL cells.

Topics: Acid Phosphatase; Amyloid Precursor Protein Secretases; Animals; Biomarkers; Calcium-Binding Proteins; Cell Culture Techniques; Culture Media, Conditioned; Fibroblasts; Humans; Intercellular Signaling Peptides and Proteins; Interleukin-6; Isoenzymes; Jagged-1 Protein; Male; Membrane Proteins; Oligopeptides; Osteoclasts; Periodontal Ligament; Random Allocation; RANK Ligand; Rats; Rats, Wistar; Receptor, Notch2; Root Resorption; Serrate-Jagged Proteins; Signal Transduction; Tartrate-Resistant Acid Phosphatase; Tooth Movement Techniques; Tooth Root

The objectives of this study were (1) to investigate the expressions of interleukin (IL)-17, RANKL (the receptor activator of NF-kappaB ligand), and osteoprotegerin (OPG) in root resorption areas during experimental tooth movement in rats, and (2) to determine the effect of IL-17 on the expressions of RANKL and OPG mRNA from human dental pulp cells.. Twelve male 6-week-old Wistar rats were subjected to an orthodontic force of 50 g to induce a mesially tipping movement of the maxillary first molars for 7 days. The expression levels of tartrate resistant acid phosphatase (TRAP), interleukin (IL)-17, IL-17 receptor (IL-17R), receptor activator of nuclear factor-kappa B ligand (RANKL), and OPG proteins were determined in dental pulp by immunohistochemical analysis. Furthermore, the effects of IL-17 on the expressions of RANKL and OPG mRNA were investigated using human dental pulp cells in vitro.. In the experimental tooth movements in vivo, resorption lacunae with multinucleated cells were observed in the 50-g group. The immunoreactivities for IL-17, IL-17R, and RANKL were detected in dental pulp tissues subjected to the orthodontic force on day 7. Moreover, IL-17 increased the mRNA expression of RANKL from human dental pulp cells in vitro.. The results of this study suggest that IL-17 and RANKL may be involved in the process of orthodontically induced inflammatory root resorption in dental pulp cells.

Topics: Acid Phosphatase; Adolescent; Animals; Cell Culture Techniques; Cells, Cultured; Dental Pulp; Female; Humans; Interleukin-17; Isoenzymes; Male; Osteoclasts; Osteoprotegerin; RANK Ligand; Rats; Rats, Wistar; Receptors, Interleukin-17; Root Resorption; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Tooth Movement Techniques

Atorvastatin (ATV) has bone anabolic properties, and alendronate (ALD) is an important antiresorptive drug. This study aimed to evaluate the effects of the combination of ALD and ATV on ligature-induced alveolar bone loss in rats.. Periodontitis was induced by ligature in 78 Wistar rats. Groups of six rats prophylactically received 0.9% saline (SAL), ALD (0.01 or 0.25 mg/kg subcutaneously) or ATV (0.3 or 27 mg/kg by gavage). Then, groups of six rats received the combination of ALD+ATV (0.25 mg/kg + 27 mg/kg, 0.01 mg/kg + 0.3 mg/kg, 0.25 mg/kg + 0.3 mg/kg or 0.01 mg/kg + 27 mg/kg) prophylactically. An extra group of six rats received therapeutic SAL or a lower-dose combination of ALD+ATV (0.01 mg/kg + 0.3 mg/kg, respectively) therapeutically. Three extra groups of six rats each received SAL or a lower-dose combination of ALD+ATV (0.01 mg/kg + 0.3 mg/kg, respectively) prophylactically or therapeutically for histometric and immunohistochemical analyses. The rats were killed on day 11 after ligature placement, and the maxillae were removed and processed for macroscopic, histomorphometric and TRAP immunohistochemical analyses. Gingival samples were collected to evaluate myeloperoxidase (MPO) activity. Blood samples were collected to measure serum bone-specific alkaline phosphatase (BALP) and transaminase levels and for hematological studies. Rats were weighed daily.. All combined therapies prevented alveolar bone loss when compared with SAL or low doses of monotherapy (ALD or ATV) (p < 0.05). The lower-dose combination of ALD+ATV (0.01 mg/kg + 0.3 mg/kg, respectively), administered either prophylactically (39.0%) or therapeutically (53.5%), prevented alveolar bone loss. Decreases in bone and cementum resorption, in leukocyte infiltration and in immunostaining for TRAP and MPO activity corroborated the morphometric findings. The lower-dose combination of ALD+ATV (0.01 mg/kg + 0.3 mg/kg, respectively) prevented BALP reduction (p < 0.05) and did not alter the level of serum transaminases. Moreover, the lower-dose combination of ALD+ATV (0.01 mg/kg + 0.3 mg/kg, respectively) also reduced neutrophilia and lymphomonocytosis and did not cause weight loss when compared with administration of SAL.. The lower-dose combination of ALD+ATV (0.01 mg/kg + 0.3 mg/kg, respectively) demonstrated a protective effect on alveolar bone loss.

Topics: Acid Phosphatase; Alanine Transaminase; Alendronate; Alkaline Phosphatase; Alveolar Bone Loss; Animals; Aspartate Aminotransferases; Atorvastatin; Body Weight; Bone Density Conservation Agents; Dental Cementum; Gingiva; Heptanoic Acids; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Infusions, Parenteral; Injections, Subcutaneous; Isoenzymes; Leukocyte Disorders; Leukocytes; Leukocytosis; Male; Monocytes; Neutrophils; Peroxidase; Pyrroles; Rats, Wistar; Root Resorption; Tartrate-Resistant Acid Phosphatase

The purposes of the present study were to evaluate the effects of frequent applications of low-level laser therapy (LLLT) on corticotomy-assisted tooth movement in a beagle dog model and to compare the effects in the mandible and maxilla.. In 4 male beagles, the maxillary and mandibular second premolars were extracted. The third premolars were corticotomized and then protracted from the canines with a continuous force of 200 g. Daily LLLT (using an aluminum gallium indium phosphide [AlGaInP] diode) was applied at the buccal mucosa of the corticotomized premolars on 1 side only. The tooth movement was measured for 8 weeks. Fluorochromes were injected intravenously at the start of the experiment (T0) and after 2 (T2), 4 (T4), and 8 (T8) weeks to evaluate new bone formation on the tension sides. Histomorphometric and immunohistologic evaluations were performed.. In the mandible, the movement of the corticotomized premolars in the LLLT plus corticotomy group was less than that in the corticotomy-only group, although the difference was not statistically significant. In the maxilla, no significant differences between the 2 groups were found. Osteoclastic and proliferating cell activities and the amount of new bone formation were greater in the mandibular LLLT plus corticotomy group than in the corticotomy-only group.. The frequent application of LLLT showed no significant effect on the corticotomized tooth movement.

Topics: Acid Phosphatase; Alveolar Process; Animals; Anthraquinones; Bicuspid; Bone Resorption; Cell Proliferation; Dogs; Fluoresceins; Fluorescent Dyes; Isoenzymes; Lasers, Semiconductor; Low-Level Light Therapy; Male; Mandible; Maxilla; Models, Animal; Orthodontic Wires; Osteoclasts; Osteogenesis; Pilot Projects; Proliferating Cell Nuclear Antigen; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tetracycline; Time Factors; Tooth Movement Techniques

The bisphosphonate alendronate (ALN) was employed with the aim of investigating its effects on dental and periodontal tissues after lateral luxation of developing molars.. Twenty-one-day-old Wistar rats had their second upper molars laterally luxated. Daily 2.5 mg kg(-1) ALN injections started at the day of the luxation; controls received sterile saline solution. The teeth were analyzed 7, 14, and 21 days after the procedure. On the days cited, the maxillae were fixed, decalcified, and embedded in paraffin or Spurr resin. The paraffin sections were stained with H&E, incubated for TRAP histochemistry or immunolabeled for osteopontin (OPN). Spurr ultrathin sections were examined in a transmission electron microscope.. After 21 days, the root apex of luxated molars without ALN was wide open and disorganized and also covered by an irregular layer of cellular cementum, which was not observed in ALN-treated animals. Ankylosis sites were observed in ALN rats in both luxated and non-luxated teeth. The TRAP-positive osteoclasts were more numerous in ALN group, despite their latent ultrastructural appearance without the presence of resorption apparatus compared to controls. OPN immunolabeling revealed a thick immunopositive line in the dentin that must be resultant from the moment of the luxation, while ALN-treated specimens did not present alterations in dentin.. The present findings indicate that alendronate inhibits some alterations in dentin and cementum formation induced by dental trauma.

Topics: Acid Phosphatase; Alendronate; Alveolar Process; Animals; Bone Density Conservation Agents; Dental Cementum; Dentin; Female; Isoenzymes; Male; Microscopy, Electron, Transmission; Molar; Odontogenesis; Osteoclasts; Osteopontin; Periodontium; Rats; Rats, Wistar; Root Resorption; Tartrate-Resistant Acid Phosphatase; Time Factors; Tooth Ankylosis; Tooth Apex; Tooth Avulsion; Tooth Root

There are multiple causes of external root resorption, but absent a disease state, it is most often observed when excessive physical force is used during orthodontic treatment. Even without mechanical stimulation, however, root resorption can still occur. The purpose of this study was to test whether Wnt signaling plays a role in pathologic root resorption, by conditionally deleting Wntless (Wls) from odontoblasts and osteoblasts and then evaluating the phenotypic effects on the maintenance of the root surface.. Ten (age, 1 month) and 20 (age, 3 months) OCN-Cre;Wls(fl/fl) mice and their wild-type littermates were evaluated using microcomputed tomography, histology, and immunohistochemistry. Phenotypic alterations in the alveolar bone, dentin, and cementum were characterized and quantified.. In a genetic model of reduced Wnt signaling, we found that RANKL expression is upregulated, and osteoprotegerin expression is downregulated. This molecular disruption results in an increase in osteoclast activity, a decrease in osteoblast activity, and extensive, spontaneous root resorption. A genetic strain of mice in which Wnt signaling is elevated exhibits thicker cementum, whereas, even in the perinatal period, OCN-Cre;Wls(fl/fl) mice exhibit thinner cementum.. Taken together, these data demonstrate that Wnts regulate cementum homeostasis, and that idiopathic cases of root resorption might have as their etiology a reduction in endogenous Wnt signaling.

Topics: Acid Phosphatase; Age Factors; Alkaline Phosphatase; Alveolar Process; Animals; Axin Protein; Dental Cementum; Dentin; Down-Regulation; Extracellular Matrix Proteins; Immunohistochemistry; Isoenzymes; Mice; Mice, Inbred Strains; Odontoblasts; Osteoblasts; Osteoprotegerin; Phenotype; Phosphoproteins; RANK Ligand; Root Resorption; Sialoglycoproteins; Tartrate-Resistant Acid Phosphatase; Tooth Cervix; Up-Regulation; Wnt Proteins; Wnt Signaling Pathway; X-Ray Microtomography

Optimum stresses for a favorable response to orthodontics are still unknown. Here, we compared the effects of initial periodontal ligament (PDL) stresses over time in orthodontic external root resorption (OERR), necrosis, and the TRAP+ cell population. Forty-two rats (Fischer CDF) were treated with 10 cN of force for 5 different time periods. Finite element (FE) models of the first maxillary molars were constructed from μCT scans to calculate initial PDL stresses. The scans were also used for OERR measurements before histology. Time, stress, and their interaction were significant to result in an OERR increase only in the regions of medium and high stress. OERR was not significantly different between control and treated animals over time in the region of low stress. After 30 days, OERR was increased by 5- and 3-fold in the zone of high- and medium-stress regions, respectively. The TRAP+ cell population initially followed the stress gradient, but changed after bone and necrotic tissue resorption. In the 30-day modeling cycle, the correspondent 3rd principal stress range to promote direct bone resorption and insignificant OERR was between -9.92 and -7.75 KPa. These translate to approximate forces of 30 to 40 cN applied at the bracket level (tipping) of a human maxillary canine.

Topics: Acid Phosphatase; Animals; Dental Stress Analysis; Disease Models, Animal; Finite Element Analysis; Isoenzymes; Maxilla; Molar; Orthodontics; Periodontal Ligament; Rats; Rats, Inbred F344; Root Resorption; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Time Factors; Tooth Movement Techniques; Tooth Root

The aim of this study was to investigate the effect of tunnel structured β-tricalcium phosphate (β-TCP) on the regenerative potential of basic fibroblast growth factor-2 (bFGF-2) in class III furcation defects in dogs. The furcations of 30 mandibular premolar teeth received: 1) 0.3% bFGF-2 solution in conjunction with β-TCP; 2) 0.3% bFGF-2 solution; and 3) no implant material (Control group). The dogs were sacrificed 8 weeks post-surgery, and healing was evaluated histologically. New bone formation was significantly greater in the bFGF-2/β-TCP group compared to the bFGF-2 solution and Control groups (p<0.01). New cementum formation in the bFGF-2/β-TCP and bFGF-2 solution groups was significantly greater than that in the Control group (p<0.01). These findings suggested that bFGF-2 alone enhances connective tissue attachment in a manner similar to the combination of bFGF-2 and β-TCP. Furthermore, this combination enhances bone formation up to the fornix in class III furcation defects.

Topics: Acid Phosphatase; Animals; Bicuspid; Biocompatible Materials; Biomarkers; Bone Substitutes; Calcium Phosphates; Cementogenesis; Collagen; Connective Tissue; Dogs; Epithelium; Female; Fibroblast Growth Factor 2; Furcation Defects; Guided Tissue Regeneration, Periodontal; Isoenzymes; Osteogenesis; Periodontal Ligament; Random Allocation; Regeneration; Root Planing; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tooth Ankylosis

To isolate, culture and identify odontoclasts in vitro and to establish a method of culturing human odontoclasts.. Healthy and retentive deciduous teeth were extracted, and then placed in α-minimum essential medium containing 0.1% collagenase and 0.2% dispase for 1 h.Odontoclasts were obtained and incubated from the absorbing root surfaces of deciduous teeth.Isolated cells were viewed by inverted phase contrast microscope firstly. Then, the isolated odontoclasts were morphologically observed by hematoxylin and eosin staining (HE) and tartrate-resistant acid phosphatase (TRAP) staining. The prepared teeth slices were cocultured with the isolated odontoclasts and scanning electronic microscope(SEM) was used to demonstrate the presence of resorption lacunae.. The isolated odontoclasts appeared as multinucleated giant cell with many vacuolus in cytoplasm. TRAP staining demonstrated that the cytoplasm of the odontoclasts was full of claret-red positive particles.Resorption lacunae on teeth slices which cocultured with odontoclasts were seen under SEM.. Enzyme digestion is an effective method to isolate odontoclasts from absorbing root surface of deciduous teeth.

Topics: Acid Phosphatase; Cells, Cultured; Child; Child, Preschool; Giant Cells; Humans; Isoenzymes; Microscopy, Phase-Contrast; Osteoclasts; Root Resorption; Staining and Labeling; Tartrate-Resistant Acid Phosphatase; Tooth Root; Tooth, Deciduous

Dental tissues have special characteristics, and its regenerative capacity is noteworthy. However, understanding the circumstances that lead to regeneration is challenging. In this study, the chronology of the healing process after immediate replantation of rat incisor teeth was examined by histological and immunohistochemical analyses within a 60-day period. Thirty-six male Wistar rats had their maxillary right incisors extracted and replanted after 15 min in saline storage. The rats were sacrificed immediately 3, 7, 15, 28, and 60 days after replantation. The histological analysis showed rupture of the periodontal ligament and formation of a blood clot, which started being replaced by a connective tissue after 3 days. At 7 days, the gingival mucosa epithelium was reinserted and areas of root resorption could be seen. At 15 days, the periodontal ligament was repaired. At 3 days, the pulp presented an absence of the odontoblast layer, which started being replaced by a connective tissue. This tissue suffered gradual calcification, filling the root canal at 28 and 60 days. The root ends were closed. The immunohistochemical analysis revealed greater expression of OP, OPG, and RANK proteins in the initial periods (0 and 3 days), while TRAP expression predominated at 28 and 60 days (P < 0.05). In conclusion, in delayed tooth replantation, there is great new bone formation activity in the earlier periods of the repair process, while a predominance of bone resorption and remodeling is observed in the more advanced periods.

Topics: Acid Phosphatase; Animals; Biomarkers; Blood Coagulation; Collagen; Connective Tissue; Dental Pulp; Dental Pulp Calcification; Epithelium; Gingiva; Immunohistochemistry; Incisor; Isoenzymes; Male; Odontoblasts; Osteopontin; Osteoprotegerin; Periodontal Ligament; RANK Ligand; Rats; Rats, Wistar; Receptor Activator of Nuclear Factor-kappa B; Root Resorption; Rupture; Tartrate-Resistant Acid Phosphatase; Time Factors; Tooth Apex; Tooth Replantation; Tooth Socket; Wound Healing

The identity of odontoclast precursors and the molecular mechanism by which odontoclasts resorb dentine remain unclear. MDPC-23 cells were derived from dental papilla cells and possessed odontoblast characteristics such as expressing dentine sialophosphoprotein (Dspp) and dentine matrix acidic phosphoprotein 1 (Dmp1). Here we induced MDPC-23 cells to have an odontoclast-like function with receptor activator of nuclear factor-κB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF). We found that tartrate-resistant acid phosphatase (TRAP)-positive cells, TRAP-positive multinucleated cells on the dentine slice were significantly increased in RANKL/M-CSF-induced cells. Osteoclast-specific genes such as Trap, osteopetrosis-associated transmembrane protein 1 (Ostm1), chloride channel 7 (Clcn7), cathepsin K (Ctsk) as well as osteoclast-specific transcription factor and microphthalmia transcription factor (MITF) were up-regulated in the treated cells, whilst the messenger RNA (mRNA) levels of Dspp, Dmp1 and Opg were reduced in the induced cells. The intracellular environment became more acidic in the RANKL/M-CSF treatment group, which resulted in more absorptive pits in dentine slices. We suggested that RANKL/M-CSF might induce odontoblast-like MDPC-23 cells to differentiate into odontoclast-like cells or function as odontoclasts. Our data might provide a new explanation for the precursors of odontoclast and root resorption.

Topics: Acid Phosphatase; Animals; Cathepsin K; Cattle; Cell Culture Techniques; Cell Differentiation; Cell Line; Cell Shape; Chloride Channels; Dentin; Extracellular Matrix Proteins; Helix-Loop-Helix Motifs; Hydrogen-Ion Concentration; Isoenzymes; Leucine Zippers; Macrophage Colony-Stimulating Factor; Membrane Proteins; Mice; Microphthalmia-Associated Transcription Factor; Odontoblasts; Osteoclasts; Phosphoproteins; RANK Ligand; RNA, Messenger; Root Resorption; Sialoglycoproteins; Tartrate-Resistant Acid Phosphatase; Transcription Factors; Up-Regulation

The aim of this study was to investigate how atopic dermatitis (AD) contributes to root resorption during orthodontic tooth movement.. Atopic dermatitis model mice and wild-type mice were subjected to an excessive orthodontic force (OF) to induce movement of the upper first molars. The expression levels of the tartrate-resistant acid phosphatase (TRAP), IL-17, IL-6, and RANKL proteins were determined in the periodontal ligament (PDL) by an immunohistochemical analysis. Furthermore, the effects of the compression force on co-cultures of CD4(+) cells from AD patients or healthy individuals and human PDL cells were investigated with regard to the levels of secretion and mRNA expression of IL-17, IL-6, RANKL, and osteoprotegerin.. The immunoreactivities for TRAP, IL-17, IL-6, and RANKL in the AD group were found to be significantly increased. The double immunofluorescence analysis for IL-17/CD4 detected immunoreaction. The secretion of IL-17, IL-6, and RANKL, and the mRNA levels of IL-6 and RANKL in the AD patients were increased compared with those in healthy individuals.. Th17 cells may therefore be associated with the deterioration of root resorption of AD mice, and may explain why AD patients are more susceptible to root resorption than healthy individuals when an excessive OF is applied.

Topics: Acid Phosphatase; Adult; Animals; CD4-Positive T-Lymphocytes; Cell Culture Techniques; Coculture Techniques; Dermatitis, Atopic; Disease Models, Animal; Female; Humans; Immunoglobulin E; Interleukin-17; Interleukin-6; Isoenzymes; Male; Mice; Mice, Inbred BALB C; Osteoprotegerin; Periodontal Ligament; RANK Ligand; Root Resorption; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Th17 Cells; Tooth Movement Techniques; Young Adult

The aim of this study was to investigate how T-helper 17 cells (Th17 cells), interleukin (IL)-17, and interleukin-6 contribute to root resorption during orthodontic tooth movement.. Fifteen male 6-week-old Wistar rats were subjected to orthodontic force of 10 or 50 g to induce a mesially tipping movement of the upper first molars for 7 days. The expression levels of TRAP, IL-17, the IL-17 receptor (IL-17R), and IL-6 proteins were determined in periodontal ligament (PDL) by immunohistochemical analysis. Moreover, the fluorescent localization immunoassay was performed to detect Th17 cells. Furthermore, the effects of IL-17 on IL-6 release were investigated using human PDL cells in vitro. The effect of IL-17 on osteoclastogenesis was evaluated by TRAP staining, actin ring staining, and the pit formation assay.. The immunoreactivity for Th17, IL-17, IL-17R, and IL-6 was detected in PDL tissue subjected to the orthodontic force on day 7. IL-17 increased the release of IL-6 from human periodontal ligament cells in a time-dependent manner. Moreover, IL-17 stimulated osteoclastogenesis from human osteoclast precursor cells, and these effects were partially suppressed by an anti-IL-6 antibody.. These results suggest that Th17 cells may aggravate the process of orthodontically induced inflammatory root resorption.

Topics: Acid Phosphatase; Actins; Adolescent; Animals; Biomarkers; Biomechanical Phenomena; Cell Culture Techniques; Cell Line; Connective Tissue; Dentin; Dose-Response Relationship, Drug; Female; Fibroblasts; Humans; Interleukin-17; Interleukin-6; Isoenzymes; Male; Molar; Orthodontic Wires; Osteoclasts; Periodontal Ligament; Rats; Rats, Wistar; Receptors, Interleukin-17; Root Resorption; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Th17 Cells; Time Factors; Tooth Movement Techniques

Root resorption is a ubiquitous although undesirable sequela to orthodontic treatment. Current methods to investigate the pathophysiology have certain limitations. In pursuit to understand and develop treatment modalities for orthodontically induced root resorption, the ability to manipulate cells within their natural extracellular matrix in a three dimensional organotypic model is invaluable. The study aimed to develop a laboratory-based organotypic model to investigate the effect of orthodontic forces on the periodontium.. Mandibular slices of male Wistar rats were maintained in Trowel-typed cultures at 37°C in 5% carbon dioxide in air for 7 days with test specimens subjected to compressive forces at 50 g and 100g by stainless steel springs. Tissue architecture and cell viability were maintained under culture conditions.. Osteoclast numbers increased significantly in both test groups whilst odontoclasts increased in the 50 g group. Immunohistochemistry demonstrated increased dentine sialoprotein expression in both test groups, suggesting changes in mineralization-related activity due to mechanical strain.. The study showed initial cellular and molecular changes of key markers that relate to root resorption in response to mechanical loading.. Severe root resorption may occur when forces applied are heavy or transmitted over an extended period and could lead to mobility and tooth loss. This ex vivo model can be used to investigate cellular and molecular processes during orthodontic tooth movement which may advance the clinical management of root resorption.

Topics: Acid Phosphatase; Animals; Biomarkers; Biomechanical Phenomena; Bone Marrow; Cell Count; Cell Survival; Dental Pulp; Disease Models, Animal; Extracellular Matrix Proteins; Immunohistochemistry; Isoenzymes; Male; Mandible; Organ Culture Techniques; Orthodontic Wires; Osteoclasts; Periodontal Ligament; Phosphoproteins; Rats; Rats, Wistar; Root Resorption; Sialoglycoproteins; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Tooth Movement Techniques

Osteoprotegerin (OPG), as an osteoclast antagonist, limits mineralised tissue resorption under physiological conditions. Previous work investigating OPG in a rat periodontal ligament (PDL) ankylosis model found no inhibitory effect on osteoclasts when OPG was administered at a dosage of 2.5mg/kg.. The object of this study was to determine whether dosages higher than 2.5 mg/kg of OPG were required to limit osteoclastic activity in an aseptic inflammatory model in rats.. Dry ice was applied for 15 minutes to the upper right first molar crown of eighteen, 8-week-old, male Sprague-Dawley rats. Three groups of 3 were injected with OPG at dosages of 2.5, 5.0 and 7.5 mg/kg of body weight immediately following the thermal insult. After 7 days, the rats were sacrificed and each maxilla processed for histological examination and stained for osteoclastic activity using tartrate-resistant acid phosphatase (TRAP). Osteoclast population numbers were estimated via light microscopy and results were analysed using a comparative mixed model statistical analysis.. Results showed OPG inhibited osteoclastic activity in a dose-dependent manner. From 2.5 mg/kg to 7.5 mg/kg, osteoclast populations were linearly reduced by 39.78% (p < 0.05). OPG did not appear to affect the inflammatory process and had varied efficacy in different regions of individual teeth.. Although osteoclastic activity reduced, it was not completely eliminated, perhaps because dosages were still inadequate, or additional factors might influence OPG and osteoclast activation in the aseptic inflammatory model.

Topics: Acid Phosphatase; Animals; Biomarkers; Cell Count; Disease Models, Animal; Dose-Response Relationship, Drug; Dry Ice; Freezing; Inflammation; Isoenzymes; Male; Maxilla; Molar; Necrosis; Odontoblasts; Osteoclasts; Osteoprotegerin; Rats; Rats, Sprague-Dawley; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tooth Crown

The differentiation and functions of osteoclasts are regulated by receptor activator of nuclear factor-κB (RANK)/receptor activator of nuclear factor-κB ligand (RANKL) system that stimulates osteoclasts formation. Macrophage colony-stimulating factor (M-CSF) is also essential for osteoclastogenesis. A recent immunocytochemical study reported that RANKL/RANK and M-CSF/c-fms were localized in the periodontal ligament of rat molars during experimental orthodontic tooth movement. The present study focused on the expressions of RANKL/RANK and M-CSF/c-fms in root resorption area during experimental tooth movement in rats. Forty 6-week-old male Wistar rats were subjected to an orthodontic force of 10 or 50 g with a closed coil spring (wire size: 0.005 inch, diameter: 1/12 inch) ligated to the maxillary first molar cleat by a 0.008 inch stainless steel ligature wire to induce a mesial tipping movement of the upper first molars. Experimental tooth movement was undertaken for 10 days. Each sample was sliced into 6 μm continuous sections in a horizontal direction and prepared for haematoxylin and eosin (H and E) and immunohistochemistry staining for tartrate-resistant acid phosphatase (TRAP), RANK, RANKL M-CSF, and c-fms in root resorption area. Statistical analysis was carried out using a Mann-Whitney U-test with a significance level of P<0.01. On days 7 and 10, immunoreactivity for RANKL/RANK and M-CSF/c-fms was detected in odontoclasts with an orthodontic force of 50 g, but not 10 g. Therefore, RANKL/RANK and M-CSF/c-fms systems may be involved in the process of root resorption by heavy orthodontic force.

Topics: Acid Phosphatase; Alveolar Process; Animals; Biomarkers; Bone Resorption; Connective Tissue; Dental Cementum; Fibroblasts; Immunohistochemistry; Isoenzymes; Macrophage Colony-Stimulating Factor; Male; Maxilla; Molar; Orthodontic Wires; Osteoclasts; Periodontal Ligament; RANK Ligand; Rats; Rats, Wistar; Receptor Activator of Nuclear Factor-kappa B; Receptor, Macrophage Colony-Stimulating Factor; Root Resorption; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Time Factors; Tooth Movement Techniques

Physiological root resorption differentiates primary from permanent teeth. The understanding of what protects and regulates root resorption might help to develop therapies to its control.. To verify the presence and distribution of ECRM and the expression of CK14, OPG, TRAP and COX-2 in the periodontal ligament (PDL) of human primary and permanent teeth. Design.  Eight primary teeth undergoing physiological or pathological root resorption and 4 permanent teeth were immunohistochemically processed for CK14, TRAP, COX-2 and OPG expression.. PDL from primary and permanent teeth showed similar morphological features; however, fewer ECRM clusters and higher immunoreactivity to CK14 were found in primary PDL. In permanent teeth, ECRM were distributed along the entire PDL tissue. Howship's lacunae were found only in primary teeth, associated with the presence of TRAP-positive cells and increase in COX-2 expression. OPG expression in primary PDL was detected in nonresorptive cervical areas and in lacunae showing reparative tissue. It was observed higher expression of OPG in all permanent teeth when compared to primary specimens.. It may be concluded that PDL from primary teeth shows less ECRM clusters and lower expression of OPG. These features may be associated with lower protection against root resorption in primary teeth.

Topics: Acid Phosphatase; Adult; Child; Child, Preschool; Cyclooxygenase 2; Dentition, Permanent; Epithelial Cells; Gene Expression; Humans; Isoenzymes; Keratin-14; Osteoprotegerin; Periodontal Ligament; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tooth, Deciduous; Young Adult

The aim of this study was to investigate how interleukin (IL)-8 (cytokine-induced neutrophil chemoattractant; CINC-1) and monocyte chemotactic protein (MCP)-1/CCL2 contribute to root resorption during orthodontic tooth movement.. Forty 6-week-old male Wistar rats were subjected to orthodontic force of 10 or 50 g to induce a mesially tipping movement of the upper first molars for 7 days. We determined the expressions of CINC-1, CXCR2, and MCP-1 proteins in root resorption area using immunohistochemistry. Furthermore, we investigated the effects of compression forces (CF) on IL-8 and MCP-1 production by human periodontal ligament (hPDL) cells. We observed an effect of chemokine treatment on rat odonto/osteoclasts in dentin slices that recapitulated root resorption.. The immunoreactivity for CINC-1/CXCR2 and MCP-1 was detected in odontoclasts and PDL fibroblasts by the orthodontic force of 50 g on day 7. CF increased the secretion and the expression of mRNA of IL-8 and MCP-1 from PDL cells in a magnitude-dependent manner. Moreover, CINC-1 and MCP-1 stimulated osteoclastogenesis from rat osteoclast precursor cells.. IL-8 (CINC-1) and MCP-1 may therefore facilitate the process of root resorption because of excessive orthodontic force.

Topics: Acid Phosphatase; Adolescent; Animals; Biomechanical Phenomena; Cell Culture Techniques; Cell Differentiation; Chemokine CCL2; Chemokine CXCL1; Cytokines; Dentin; Female; Fibroblasts; Humans; Immunohistochemistry; Interleukin-8; Isoenzymes; Male; Molar; Osteoclasts; Periodontal Ligament; Rats; Rats, Wistar; Receptors, Interleukin-8B; Root Resorption; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Tooth Movement Techniques

Estrogen withdrawal causes marked bone loss in the appendicular skeleton but slightly affects mandibular cancellous bone; in contrast, little is known of its effects on alveolar wall turnover associated with tooth drift. In this study, we assessed short-term changes in alveolar wall turnover after an ovariectomy and compared it to other bone sites exhibiting different levels of turnover.. Forty Sprague-Dawley rats were ovariectomized or sham operated. Right mandibles and femurs were processed without demineralization for bone histomorphometry in three different sites: the alveolar wall around the first molar buccal root, apical interradicular bone, and femoral metaphysis. Bone changes were assessed 14 and 28 days after the ovariectomy. Data were compared using non-parametric statistics.. At 14 days, on the resorption side of the alveolar wall, resorption parameters were higher in the ovariectomized rats (P <0.01), whereas the formation was lower (P <0.05); on the formation side, the daily mineral apposition rate increased (P <0.01). The root resorption was higher in ovariectomized rats (P <0.05). In the periodontal ligament, the numbers of osteoclast precursors were significantly higher. At 28 days, the drift slowed down in both the sham and ovariectomized groups. The ovariectomy had no effect on interradicular bone turnover, whereas bone loss and numbers of osteoclasts were strongly increased in the femur as soon as 14 days after the ovariectomy.. Estrogen withdrawal had transient repercussions on alveolar wall turnover. The different reactivities of the three envelopes studied suggest that a response to an ovariectomy in the short term is related to initial basal turnover.

Topics: Acid Phosphatase; Alveolar Process; Animals; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Biomarkers; Bone Remodeling; Bone Resorption; Estrogens; Female; Femur; Isoenzymes; Mandible; Molar; Osteoclasts; Osteogenesis; Ovariectomy; Periodontal Ligament; RANK Ligand; Rats; Rats, Sprague-Dawley; Root Resorption; Tartrate-Resistant Acid Phosphatase; Time Factors; Tooth Socket

Root resorption lacunae are principally formed by odontoclasts. While these cells develop from the same origin as osteoclasts, odontoclasts normally have fewer nuclei and a less clear zone compared with osteoclasts. We therefore, hypothesized that odontoclasts possess less differentiation in matrix resorption characteristics than osteoclasts. To test our hypothesis, we compared the TRAP-positive area and the expression patterns of two important proteolytic enzymes, cathepsin K and matrix metalloproteinase-9 (MMP-9), between odontoclasts and osteoclasts. We focused on physiological root resorption in the rat molar, which is a useful experimental model for estimating odontoclasts and osteoclasts. Observations showed the number of nuclei and the TRAP-positive area of odontoclasts to be significantly less compared with osteoclasts. Using in situ hybridization and double labeling fluorescence in situ hybridization showed the majority of odontoclasts to express both cathepsin K and MMP-9, especially 4 and 5 weeks of age, when physiological root resorption occurs actively. Moreover, putative precursor cells of odontoclasts, which typically appeared in the middle of the periodontal ligament at 3 weeks of age, expressed both enzymes. In contrast, the majority of matured osteoclasts expressed only cathepsin K but not MMP-9. We suggest that odontoclasts are comparable to osteoclasts with less differentiation with regard to the expression of proteolytic enzymes.

Topics: Acid Phosphatase; Animals; Cathepsin K; Cathepsins; Immunohistochemistry; In Situ Hybridization; In Situ Hybridization, Fluorescence; Male; Matrix Metalloproteinase 9; Molar; Osteoclasts; Rats; Rats, Wistar; RNA, Messenger; Root Resorption

External apical root resorption (EARR) is an unwanted sequelae of orthodontic treatment. Genetic factors account for approximately 64% of the EARR variation in humans. Inbred mice offer a model to control the environmental factors and genetic heterogeneity that complicate human genetic studies. Genetically distinct inbred mice and their offspring (F1s) were analyzed to examine the mode of inheritance and the influence of parental sex on the susceptibility to root resorption associated with orthodontic force (RRAOF).. RRAOF was determined histologically for male and female mice of the A/J, DBA/2J, and BALB/cJ strains, and the A/JxDBA/2J and A/JxBALB/cJ crosses (10 males and 10 females/reciprocal cross). RRAOF was induced by tipping the maxillary first molar mesially for 9 days.. Sex differences were observed only among the mice of the BALB/cJ strain. Two patterns of inheritance were observed; F1s from the A/JxBALB/cJ cross were resistant, suggesting that the A/J have dominant resistance alleles. On the other hand, F1s from the A/JxDBA/2J cross showed RRAOF intermediate between their parental mice, suggesting a polygenic trait.. These results provide evidence of a traceable and polygenetic component affecting RRAOF in mice.

Topics: Acid Phosphatase; Alleles; Animals; Biomarkers; Crosses, Genetic; Disease Models, Animal; Female; Genes, Dominant; Genetic Predisposition to Disease; Isoenzymes; Male; Mice; Mice, Inbred A; Mice, Inbred BALB C; Mice, Inbred DBA; Mice, Inbred Strains; Molar; Multifactorial Inheritance; Root Resorption; Sex Factors; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Tooth Movement Techniques

To investigate how the preapplication of orthodontic forces to the donor teeth affects the periodontal healing after transplantation.. The orthodontic force (1.5 cN) was applied to the maxillary right molars of 6-week-old male Spraque-Dawley rats (n = 21) in the experimental side, and the left side of the same animals was used as the control. After 7 days, both right and left maxillary second molars were extracted or replanted. Periodontal conditions were evaluated in the histological specimens 7 days after applying orthodontic force (before and after extraction) and 14 days after replantation.. The application of orthodontic force for 7 days significantly increased the periodontal ligament (PDL) space and also the width of the alveolar socket, which resulted in a rich attached PDL to the root surface of the extracted teeth. Significantly more root resorption was also detected in the control side without preapplication of orthodontic force 14 days after replantation. This root resorption might involve in the disruption of the PDL.. These results suggested that the preapplication of orthodontic force to the donor teeth increased the PDL width and eased the extraction, which might decrease root resorption after replantation.

Topics: Acid Phosphatase; Alveolar Process; Animals; Biomarkers; Isoenzymes; Male; Models, Animal; Molar; Orthodontic Wires; Osteoclasts; Periodontium; Rats; Rats, Sprague-Dawley; Root Resorption; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Time Factors; Tooth Apex; Tooth Extraction; Tooth Replantation; Tooth Root; Tooth Socket; Wound Healing

Root resorption (RR) is an unwanted sequela of orthodontic treatment. Despite rigorous investigation, no single factor or group of factors that directly causes RR has been identified. The purpose of this study was to examine the effect of the genotype on susceptibility or resistance to develop RR secondary to orthodontic force. Nine-week-old male mice from eight inbred strains were used and randomly distributed into control (C) or treatment (T) groups as follows: A/J (C = 9,T = 9), C57BL/6J (C = 7,T = 8), C3H/HeJ (C = 8,T = 6), BALB/cJ (C = 8,T = 6), 129P3/J (C = 6,T = 8), DBA/2J (C = 8,T = 9), SJL/J (C = 8,T = 10), and AKR/J (C = 9,T = 8). Each of the treated mice received an orthodontic appliance to tip the maxillary left first molar mesially for 9 days. Histological sections of the tooth were used to determine RR and tartrate resistant acid phosphatase (TRAP) activity. The Wilcoxon ranked-sum non-parametric test was used to evaluate differences between the groups. The results showed that the DBA/2J, BALB/cJ, and 129P3/J inbred mouse strains are highly susceptible to RR, whereas A/J, C57BL/6J and SJL/J mice are much more resistant. The variation in the severity of RR associated with orthodontic force among different inbred strains of mice when age, gender, food, housing, and orthodontic force magnitude/duration are controlled support the hypothesis that susceptibility or resistance to RR associated with orthodontic force is a genetically influenced trait.

Topics: Acid Phosphatase; Animals; Biomarkers; Dental Stress Analysis; Disease Models, Animal; Genetic Predisposition to Disease; Genotype; Isoenzymes; Male; Mice; Mice, Inbred Strains; Random Allocation; Reproducibility of Results; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tooth Movement Techniques

To identify clastic cells on the root surfaces of torqued human premolars.. A continuous force of 600 cNmm was applied to upper first premolars in patients 13-16 years of age by using a precise biomechanical model with superelastic wires (NiTi-SE). The 28 teeth in 14 patients were divided into five groups (control [nonmoved], and moved for either 1, 2, 3, or 4 weeks) and processed for tartrate-resistant acid phosphatase (TRAP) histochemistry and transmission electron microscopy.. Mononuclear TRAP-positive cells appeared at 2 weeks, where as large multinucleated TRAP-positive cells were numerous at 3 and 4 weeks. Ultrastructural examination revealed many clastic cells in contact with resorption lacunae. In addition, some cementoblast-like cells appeared secreting new cementum over previously resorbed lacunae.. In general, resorption lacunae and the number of clastic cells, which increased with the duration of the applied force, were found on the cementum surface at the pressure areas. Some signs of cementum repair were also noticed, even with the maintenance of the level of the force.

Topics: Acid Phosphatase; Adolescent; Bicuspid; Cementogenesis; Dental Cementum; Dental Stress Analysis; Elasticity; Histocytochemistry; Humans; Isoenzymes; Microscopy, Electron, Transmission; Orthodontic Wires; Osteoclasts; Periodontal Ligament; Root Resorption; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Tooth Movement Techniques; Torque

Pro-inflammatory cytokines, such as interleukin-1 (IL-1) and tumour necrosis factor-alpha (TNF-alpha), are believed to play a role in the biological processes involved in the course of orthodontic tooth movement and especially in root resorption. The inhibition of cytokine activity, e.g. by soluble receptors, could be beneficial in reducing this unwanted side-effect. The aim of this study was to investigate the role of cytokines IL-1 and TNF-alpha in the course of experimentally induced tooth movement. The upper left first molar was moved orthodontically in 80 male Wistar rats using a coil spring with a force of 0.5 N. Starting at day -1, three groups of 20 animals each received daily intraperitoneal injections (ip) of 2 ml of 1 mug/ml soluble receptors (a) to IL-1(sIL-RII), (b) to TNF-alpha (sTNF-alpha-RI) and (c) a combination of (a) and (b). Twenty animals served as the control. After 3, 6, 9 and 12 days, the animals were killed in groups of five. The amount of tooth movement was registered and the maxillae were prepared for histological and histomorphometric analysis. Osteoclasts and odontoclasts were identified using tartrate-resistant acid phosphatase (TRAP) histochemistry. The amount of tooth movement was reduced in all receptor-treated groups by approximately 50 per cent. At the same time, the number of TRAP-positive cells on the desmodontal bone surface and on the surface of the roots was reduced. Thus, systemic application of soluble receptors to IL-1 and TNF-alpha following experimental induction of tooth movement in the rat reduced the number of osteoclasts as well as odontoclasts.

Topics: Acid Phosphatase; Animals; Biomarkers; Injections, Intraperitoneal; Interleukin-1; Isoenzymes; Male; Maxilla; Molar; Odontoblasts; Orthodontic Wires; Osteoclasts; Rats; Rats, Wistar; Receptors, Interleukin-1; Receptors, Interleukin-1 Type II; Receptors, Tumor Necrosis Factor; Root Resorption; Tartrate-Resistant Acid Phosphatase; Time Factors; Tooth Movement Techniques; Tooth Root; Tumor Necrosis Factor-alpha

The aim of the present study was to investigate the effect of systemic administration of low-dose doxycycline (DC) on orthodontic root resorption. The effect on alveolar bone, the cell population involved, and the amount of tooth movement were also evaluated.Fifty-six 40-50-day-old male Wistar rats were used. Six animals served as untreated controls. Six animals were only administered DC for 7 days, by means of a mini-osmotic pump implanted subcutaneously. In 44 animals the maxillary first molar was mesialized by a fixed orthodontic appliance exerting 50 g force upon insertion. In 28 of these animals DC was administered at the time of appliance insertion and throughout the experiment. The animals were sacrificed 7, 10 or 14 days after force application and block sections processed for analysis. An area including the mesial aspect of the distopalatal root and the adjacent inter-radicular alveolar bone was histomorphometrically evaluated. The root resorption area, absolute alveolar bone area, distance between first and second molars, number of odontoclasts, osteoclasts, mononuclear cells on the root, tartrate-resistant acid phosphatase (TRAP)-positive cells on the root, bone, and in the periodontal ligament (PDL) were compared between DC-treated and non-DC-treated animals. The results revealed a significant reduction in root resorption, the number of odontoclasts, osteoclasts, mononuclear cells on the root surface, and TRAP-positive cells on the root and bone for the DC-administered group. The absolute alveolar bone area was greater, whereas the distance between the first and second molars did not differ between groups. In conclusion, systemic administration of low-dose DC in rats may have an inhibitory effect on orthodontically induced resorptive activity.

Topics: Acid Phosphatase; Alveolar Bone Loss; Alveolar Process; Animals; Anti-Bacterial Agents; Biomarkers; Doxycycline; Infusion Pumps; Injections, Subcutaneous; Isoenzymes; Leukocytes, Mononuclear; Male; Molar; Osteoclasts; Periodontal Ligament; Rats; Rats, Wistar; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tooth Movement Techniques; Tooth Root

Calcitonin is a known inhibitor of osteoclastic bone resorption, but it remains uncertain whether calcitonin also regulates human odontoclastic activity, particularly during the physiological process of root resorption. In this study, we examined the expression of calcitonin receptors in human odontoclasts and the effect of calcitonin on root resorption, using immunocytochemistry and reverse transcription-polymerase chain reaction (RT-PCR). Actin-ring formation was used to assess cytostructural changes during resorption activity. Our results show that calcitonin receptors are expressed in human odontoclasts freshly isolated from deciduous teeth of the periodontal region. Calcitonin inhibited actin-ring formation and resorption activity. This calcitonin-induced inhibition was mimicked by forskolin and dibutyryl-adenosine 3',5'-cyclic monophosphate (db-cAMP), which are protein kinase A (PKA) activators, but not by phorbol 12-myristate 13-acetate, a protein kinase C activator. Pretreatment with adenosine 3',5'-cyclic monophosphothioate Rp diastereomer (Rp-cAMPS), a PKA inhibitor, suppressed the calcitonin-induced inhibition of actin-ring formation. These results indicate that calcitonin receptor activation suppresses odontoclastic root resorption via PKA, a signaling pathway different from that in human osteoclasts.

Topics: Acid Phosphatase; Actins; Bucladesine; Calcitonin; Colforsin; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Gene Expression; Humans; Immunohistochemistry; Isoenzymes; Microscopy, Electron, Scanning; Microscopy, Phase-Contrast; Osteoclasts; Protein Kinase C; Receptors, Calcitonin; Reverse Transcriptase Polymerase Chain Reaction; Root Resorption; Signal Transduction; Tartrate-Resistant Acid Phosphatase; Tetradecanoylphorbol Acetate; Thionucleotides; Tooth, Deciduous

In this study, the role of the inflammatory cytokines interleukin-1 (IL-1) and tumor necrosis factor alpha (TNFalpha) in the course of mechanically induced root resorption was investigated.. Mechanical induction of root resorption was performed on the upper left first molars in 18 male Wistar rats according to the method of Nakane and Kameyama. Starting on day minus 1, six animals received daily intraperitoneal injections of 2 ml of 1 micro g/ml soluble receptors to IL-1 (sIL-1RII) and another six animals were administered the same dose of soluble receptors to TNFalpha (sTNFalpha-RI). Six animals served as a control. On d 7 the left maxillae were prepared for histological and morphometric analysis of the extent of the root resorption that had developed.. The qualitative and quantitative results demonstrated that in both receptor groups the amount of root resorption was significantly reduced. Especially following systemic application of sTNFalpha-RI, root resorption was nearly completely prevented.. Our results indicate that IL-1 and more particularly TNFalpha are important for the induction and the further process of mechanically induced root resorption in the rat.

Topics: Acid Phosphatase; Animals; Biomarkers; Dental Cementum; Dentin; Gingiva; Interleukin-1; Isoenzymes; Lymphocytes; Male; Molar; Osteoclasts; Periodontal Ligament; Rats; Rats, Wistar; Receptors, Interleukin-1; Receptors, Tumor Necrosis Factor; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tumor Necrosis Factor-alpha

Orthodontic movement of non-occluding teeth may result in undesirable apical root resorption. These teeth present with a histologically altered periodontium and are considered to be hypofunctional. The purpose of this study was to compare the amount of root resorption associated with a normal and a hypofunctional periodontium in rats during experimental tooth movement caused by heavy continuous force. The mandibular first molar was induced into a non-occluding condition in the hypofunctional periodontium group. Mesial orthodontic force was applied by means of 50-gram-force closed-coil springs for 15 days in both groups. The active root-resorption lacunae from histological sections, identified by tartrate-resistant acid phosphatase, were measured in terms of length, depth, and area. The results showed that the amount of root resorption was significantly greater in teeth with a hypofunctional periodontium than in those with a normal periodontium (p < 0.05). These results suggest that orthodontic movement of non-occluding teeth should be performed with caution.

Topics: Acid Phosphatase; Animals; Biomarkers; Isoenzymes; Male; Malocclusion; Molar; Orthodontic Wires; Periodontium; Rats; Rats, Sprague-Dawley; Root Resorption; Statistics, Nonparametric; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Tooth Movement Techniques; Weight-Bearing

The process of dental root resorption and subsequent cementum regeneration has not been sufficiently elucidated. This study aimed to examine the process of the root resorption and cementum regeneration during physiological tooth drift using a rat model, and to evaluate this experimental model.. Distal roots in mandibular first molars and the surrounding periodontal tissues were investigated with light and electron microscopy. The light microscopic approach included histochemical and histometric analyses utilizing the tartrate-resistant acid phosphatase (TRAP) reaction.. Root resorption was observed in the distal side of the roots and was most active in 5- to 6-week-old rats, and gradually decreased hereafter. An increase in the number of TRAP-positive mononuclear cells, which seemed to be odontoclast precursor cells, preceded the increase in the number of odontoclasts. Root resorption was transient, and was followed by the new formation of acellular extrinsic fiber cementum accompanied with only a slight inflammation, and therefore classified as external surface resorption. Preparation for new cementum started adjacent to the resorption areas when root resorption was most active.. The root resorption during drift in rats is transient and followed by acellular extrinsic fiber cementum regeneration. Cellular kinetics suggested that odontoclast precursor cells are supplied as mononuclear cells from vascular spaces.

Topics: Acid Phosphatase; Animals; Coloring Agents; Dental Cementum; Isoenzymes; Microscopy, Electron, Scanning; Osteoclasts; Rats; Rats, Wistar; Regeneration; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tooth Migration

The present study was undertaken to determine the frequency and extent of apical root resorption associated with induced periradicular lesions in mice.. Bone and root resorption was quantified by using two- and three-dimensional micro-computed tomography (mu-CT) in the lower first molars of mice subjected to pulp exposure and infection.. mu-CT measurements showed significant apical resorption in exposed and infected teeth, resulting in an average distal root shortening of 12.7% (P <.001 vs unexposed). These findings were confirmed with three-dimensional reconstituted images that showed thinning and shortening of the distal root. Tartrate-resistant acid phosphatase clastic cells were associated with resorption lacunae on the cementum of root apices, as well as on bone at the periphery of the periradicular lesions. Brown and Brenn staining showed the presence of bacteria in dentinal tubules adjacent to resorbed cementum.. Apical root resorption is a prominent and consistent finding associated with periradicular infection in the mouse. This species represents a convenient model for studying the pathogenesis of inflammatory root resorption in vivo.

Topics: Acid Phosphatase; Animals; Biomarkers; Bone Resorption; Coloring Agents; Dental Cementum; Dental Pulp Diseases; Dental Pulp Exposure; Dentin; Disease Models, Animal; Gram-Negative Bacteria; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Isoenzymes; Male; Mandibular Diseases; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Molar; Periapical Diseases; Regression Analysis; Root Resorption; Statistics as Topic; Tartrate-Resistant Acid Phosphatase; Tomography, X-Ray Computed; Tooth Apex; Tooth Root

Whether periodontal ligament (PDL) tissue is capable of inducing root resorption was examined. The distal root of the rat molar was sectioned at the furcation and the PDL tissue removed from the root (non-PDL group, n=40). The distal root with the PDL intact was also prepared (PDL-intact group, n=40). The roots were transplanted into the dorsal skin of the rat. On the 1st, 3rd, 5th, 7th, 10th, 14th, 21st or 28th day after transplantation, the roots were removed together with surrounding dorsal subcutaneous tissue and were fixed, demineralized and embedded in paraffin. Serial sections from each block were stained with haematoxylin and eosin or by the tartrate-resistant acid phosphatase (TRAP) method to observe root-resorbing cell formation. Cyclo-oxygenase-2 (COX2) was also detected immunohistologically to examine prostaglandin E(2) production. On the 7th day after transplantation, multinucleated root-resorbing cells with TRAP were observed in the PDL-intact group. The number of TRAP-positive cells peaked on the 10th day after transplantation. COX2-positive cells were observed in PDL during the early experimental stages. No root resorption was seen in the non-PDL group. These results suggest that PDL tissue is involved in the formation of root-resorbing cells and root resorption.

Topics: Acid Phosphatase; Analysis of Variance; Animals; Cyclooxygenase 2; Dinoprostone; Isoenzymes; Male; Models, Animal; Osteoclasts; Periodontal Ligament; Prostaglandin-Endoperoxide Synthases; Rats; Rats, Inbred Lew; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tooth Root

Periodontal ligament (PDL) cells play an important role in maintaining the homeostasis of periodontal tissues. However, it is not known how PDL cells contribute to osteoclastogenesis. In this study, we examined the consequences of cell-to-cell interactions between peripheral blood mononuclear cells (PBMCs) and PDL cells during osteoclastogenesis. PBMCs were co-cultured directly or indirectly with PDL cells for two to four weeks. PBMCs that were directly co-cultured with PDL cells formed significantly more resorption pits on dentin slices than did PBMCs that were cultured alone. However, soluble factor(s) produced from PDL cells inhibited the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells. Furthermore, PDL cells expressed both receptor activator nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) mRNA. In conclusion, PDL cells support osteoclastogenesis through cell-to-cell contact. PDL cells might regulate osteoclastogenesis by opposing mechanisms--stimulation of resorptive activity by RANKL and inhibition by OPG--thus affecting processes such as periodontitis and orthodontic tooth movement.

Topics: Acid Phosphatase; Adult; Animals; Carrier Proteins; Cattle; Cell Communication; Cell Differentiation; Cells, Cultured; Coculture Techniques; Dentin; Enzyme Inhibitors; Glycoproteins; Humans; Isoenzymes; Leukocytes, Mononuclear; Ligands; Male; Membrane Glycoproteins; NF-kappa B; Osteoclasts; Osteoprotegerin; Periodontal Ligament; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; RNA, Messenger; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tumor Necrosis Factor-alpha

For elucidation of how physiological root resorption of deciduous teeth is initiated, the cellular events that occur surrounding the root of rabbit deciduous teeth before and at the onset of physiological root resorption were observed by means of light and electron microscopy. In addition, the cytodifferentiation of odontoclasts during the initial phase of this root resorption was evaluated by histochemical staining of tartrate-resistant acid phosphatase (TRAP) activity as a marker odontoclasts and their precursors. The present investigation was focused on the physiological root resorption of the deciduous lower second molar of rabbits from Day 0-5 postnatally. At birth, the deciduous molar had not erupted yet, and no TRAP-positive cell could be found surrounding the tissue adjacent to the root of the deciduous tooth. TRAP-positive mononuclear cells were initially detected in the coronal portion of the dental follicle of the permanent tooth at Day 1 postnatally. Ultrastructurally, these mononuclear cells had moderate numbers of mitochondria and short-strand rough endoplasmic reticulum, as well as scattered free ribosomes throughout their cytoplasm. TRAP-positive mononuclear cells then appeared in the cementoblast layer immediately adjacent to the surface of the deciduous roots. These mononuclear cells projected cytoplasmic extensions between the cementoblasts and made contact with the cementum. At that time, cell-cell contact was frequently observed between these mononuclear cells and cementoblasts. During 3-5 days postnatally, the number of TRAP-positive multinucleate odontoclasts on the root surface gradually increased. They had well-developed ruffled borders and made typical resorption lacunae on the root surface of the deciduous tooth. During this early postnatal period, neither inflammatory cells nor necrotic tissue could be observed surrounding the deciduous root. This study demonstrates that the dental follicle of the permanent tooth as well as the connective tissue adjacent to the deciduous root might play important role in site- and time-specific recruitment, development, and activation of odontoclasts before and at the onset of physiological root resorption.

Topics: Acid Phosphatase; Animals; Animals, Newborn; Cell Differentiation; Dental Cementum; Isoenzymes; Microscopy, Electron; Organelles; Osteoclasts; Rabbits; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tooth Exfoliation; Tooth Root; Tooth, Deciduous

Adverse effects of corticosteroids on bone metabolism raise concerns as to whether steroid treatment may influence orthodontic movement. This study examined the effect of prednisolone on orthodontic movement using an established rat model. The corticosteroid treated group (N = 6) was administered prednisolone (1 mg/kg) daily, for a 12-day induction period; the control group (N = 6) received equivalent volumes of saline. On day 12, an orthodontic appliance was placed which exerted 30 g of mesial force to the maxillary first molar. Animals were sacrificed on day 24 and tooth movement was measured. Sagittal sections of the molars were stained with haematoxylin and eosin, and for tartrate-resistant acid phosphatase (TRAP) activity. While there were no significant differences in the magnitude of tooth movement between the 2 groups, steroid-treated rats displayed significantly less root resorption on the compression side and fewer TRAP-positive cells within the PDL space on the same side. This suggests steroid treatment suppressed clastic activity.

Topics: Acid Phosphatase; Alveolar Bone Loss; Animals; Anti-Inflammatory Agents; Bone Remodeling; Isoenzymes; Male; Maxilla; Orthodontic Appliances; Osteoclasts; Periodontal Ligament; Prednisolone; Rats; Rats, Wistar; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tooth Movement Techniques

Orthodontic tooth movement may be enhanced by the application of a magnetic field. Bone remodelling necessary for orthodontic tooth movement involves clastic cells, which are tartrate-resistant acid phosphatase (TRAP) positive and which may also be regulated by growth hormone (GH) via its receptor (GHR). The aim of this study was to determine the effect of a static magnetic field (SMF) on orthodontic tooth movement in the rat. Thirty-two male Wistar rats, 9 weeks old, were fitted with an orthodontic appliance directing a mesial force of 30 g on the left maxillary first molar. The appliance incorporated a weight (NM) or a magnet (M). The animals were killed at 1, 3, 7, or 14 days post-appliance insertion, and the maxillae processed to paraffin. Sagittal sections of the first molar were stained with haematoxylin and eosin (H&E), for TRAP activity or immunohistochemically for GHR. The percentage body weight loss/gain, magnetic flux density, tooth movement, width of the periodontal ligament (PDL), length of root resorption lacunae, and hyalinized zone were measured. TRAP and GHR-positive cells along the alveolar bone, root surface, and in the PDL space were counted. The incorporation of a SMF (100-170 Gauss) into an orthodontic appliance did not enhance tooth movement, nor greatly alter the histological appearance of the PDL during tooth movement. However significantly greater root resorption (P = 0.016), increased width of the PDL (P = 0.017) and greater TRAP activity (P = 0.001) were observed for group M at day 7 on the compression side. At day 14 no differences were observed between the appliance groups.

Topics: Acid Phosphatase; Analysis of Variance; Animals; Bone Remodeling; Cell Count; Immunoenzyme Techniques; Isoenzymes; Magnetics; Male; Maxilla; Molar; Orthodontic Appliances; Periodontal Ligament; Periodontium; Rats; Rats, Wistar; Receptors, Somatotropin; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tooth Movement Techniques; Tooth Root

This study was conducted to investigate the nature of root resorption resulting from intrusive forces applied to the rat lower molars, by means of histological and histochemical techniques with tartrate resistant acid phosphatase (TRAP). Thirty-eight 13-week-old Wistar strain male rats were used. Intrusive force was created by a fixed appliance which was adjusted to exert an initial force of 50 g for the duration of 1, 2, and 3 weeks. The degree of root resorption and distribution of TRAP positive cells were evaluated. On the root surface, the TRAP positive scores were low in the apical regions. Significant differences in the scores were found in the inter-radicular region of the roots between the experimental and control groups for the 2- and 3-week groups. More active resorption of bone occurred during the experimental period, as denoted by greater TRAP positive scores on the bone than on the root surface. Root resorption scores in the apical root region were larger in the 2- and 3-week groups than in the 1-week group. Significant differences in the root resorption scores were also found between the 1- and 3-week groups in the inter-radicular region, indicating that intrusive force application of a longer duration may lead to a higher frequency of root resorption. It is shown that, irrespective of the level of TRAP positive cells and root resorption scores, the degree of root resorption activity is higher in the apical root region than in the inter-radicular area. These results indicate that cellular cementum may be resorbed more easily because of its richer organic components and low mineralized structure.

Topics: Acid Phosphatase; Alveolar Bone Loss; Analysis of Variance; Animals; Biomarkers; Coloring Agents; Dental Cementum; Isoenzymes; Male; Molar; Rats; Rats, Wistar; Root Resorption; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Tooth Apex; Tooth Movement Techniques; Tooth Root

Delays in the appearance ofosteoclasts at compression sites occur following orthodontic appliance reactivation when this is done during the period of osteoclast recruitment. This study examined changes in alveolar bone after appliance reactivation at a time coinciding with the peak expansion of the osteoclast population following the first appliance activation.. Orthodontic appliances were activated with 40 g on maxillary molars followed by a reactivation with the same force after 4 days in one group and sham reactivation in the other. Rats were killed at 0, 1, 3, 6, and 10 days thereafter. Orthodontic movement was measured cephalometrically. TRAP and interleukin-1 alpha (IL-1alpha) were measured biochemically, and changes in osteoclasts and root resorption were assessed at both compression and tension sites histomorphometrically.. Teeth in the reactivated group displayed more initial displacement than controls but no more tooth movement 10 days following appliance reactivation. Also, increases in osteoclast numbers and surface percent, as well as alveolar bone Tartrate-resistant acid phosphatase (TRAP), became evident in the treated animals only 10 days after reactivation. However, IL-1alpha was elevated in alveolar bone within 1 hr following appliance reactivation but returned to baseline by day 1. There were no treatment-related difference in nuclear number per osteoclast or trabecular surface per osteoclast. Significant treatment-related increases in root resorption were evident at compression sites by day 10.. These findings indicate that after appliance reactivation during the height of osteoclastic stimulation, a second cohort of osteoclasts can be recruited, but only after a delay of several days. This delay is not due to a failure to produce IL-1alpha in the tissues.

Topics: Acid Phosphatase; Alveolar Process; Animals; Apoptosis; Cell Count; Cell Nucleus; Interleukin-1; Isoenzymes; Male; Orthodontic Appliances; Osteoclasts; Rats; Rats, Sprague-Dawley; Root Resorption; Surface Properties; Tartrate-Resistant Acid Phosphatase; Time Factors; Tooth; Tooth Movement Techniques

The purpose of this study was to acquire tooth movement, histomorphometric and biochemical data on oral tissues that had previously been loaded with calibrated orthodontic forces. One hundred and forty-four male Sprague-Dawley rats were randomly divided into two groups: Group I, orthodontic appliances placed for 16 days to mesially move maxillary first molars with an initial force of 40 gm, and group II, sham orthodontic treatment. Seven to twelve rats were killed at each of six times after removal of appliance. Tooth movement was measured cephalometrically, alveolar bone turnover by histomorphometry, and tissue phosphatase levels biochemically. Treated molars moved distally more rapidly than the shams (13.9 vs 5.0 microns/day). The appliance removal group had a persistent 10-fold elevation in root resorption on the mesial (p < 0.0001), as well as early elevations in osteoclasts on the mesial and osteoblasts on the distal (p < 0.001) that returned to control by 3 to 5 days. Acid, alkaline phosphatase, and tartrate-resistant acid phosphatase (TRAP) remained elevated in the tissues until 10 days (p < 0.0001). Changes in the dynamic measures of bone formation were characterized by low rates at days 1 and 3 (p < 0.01), elevating thereafter on the mesial and the converse on the distal. Orthodontic tooth movement relapses, and bone remodeling continues for several days after removal of appliance consistent with the direction of loading, orthodontic treatment stimulates root resorption at sites that were loaded in pressure without detectable recovery, and root resorption does not increase at the tension sites.

Topics: Acid Phosphatase; Alkaline Phosphatase; Alveolar Process; Analysis of Variance; Animals; Bone Remodeling; Dental Stress Analysis; Isoenzymes; Linear Models; Male; Molar; Orthodontic Appliances; Rats; Rats, Sprague-Dawley; Recurrence; Root Resorption; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Time Factors

Recent studies revealed that the initial root resorption occurred in the peripheries of the necrotic periodontal ligament (PDL) and was performed by mono-nucleated non-clast macrophage- and fibroblast-like cells (Brudvik and Rygh, 1993a, b). The aim of the present transmission electron microscopic (TEM) investigation was to study in more detail the cells involved in removal of the main hyalinized tissue and those involved in root resorption, occurring on the root surface situated beneath the main hyalinized tissue. Twelve male Wistar rats were used. The maxillary first molar was moved mesially by a fixed orthodontic appliance for 7 and 10 days. The results indicate that multi-nucleated giant cells (MNGC) without a ruffled border surface, as well as mono-nucleated macrophage-like cells were responsible for removal of the necrotic tissue and also for resorption of the surface parts of the root cementum. Although the present MNGC showed many morphological traits similar to the observed odontoclasts and osteoclasts, except for their lack of ruffled borders, it is assumed that they are derived from the mono-nucleated phagocytic system. Multi-nucleated clast-like cells with ruffled border were never observed near the remnants of the necrotic tissue. Such cells were found only in the resorption lacunae on root and bone surfaces.

Topics: Acid Phosphatase; Animals; Dental Cementum; Giant Cells; Hyalin; Immunoenzyme Techniques; Isoenzymes; Macrophages; Male; Mast Cells; Necrosis; Osteoclasts; Periodontal Ligament; Phagocytosis; Rats; Rats, Wistar; Root Resorption; Tartrate-Resistant Acid Phosphatase; Time Factors; Tooth Movement Techniques

A previous investigation on the initial phase of root resorption associated with orthodontic overcompression of local areas of the periodontal ligament (PDL), indicated that a differentiation should be made between two stages: (1) the very first resorption occurring in the periphery of the main necrotic zone; and (2) the root resorption occurring on that part of the root surface situated beneath the main bulk of necrotic tissue (Brudvik and Rygh, 1993a). The aim of the present investigation was to study the latter stage. Attention was focused on: (1) the possible association between the presence of necrotic tissue and root resorption; and (2) the cells that invaded and removed the necrotic tissue, as well as the cells that started to remove/resorb the cementum. Mesial movement of the upper first molars (rats) and lower first molars (mice) was performed by a fixed orthodontic appliance. The results indicate an association between the root resorption, and the presence and active removal of the hyalinized tissue. Root resorption beneath the main hyalinized zone occurred in areas where invading cells were observed close to the root surface. The majority of the cells involved in removal of the necrotic tissue and resorption of the root surface were multi-nucleated and TRAP-positive. It is hypothesized that multi-nucleated TRAP-positive cells when reaching the subjacent contaminated and damaged root surface after having removed necrotic PM tissue, continued to remove the cementum surface.

Topics: Acid Phosphatase; Alveolar Bone Loss; Animals; Dental Cementum; Female; Giant Cells; Hyalin; Immunoenzyme Techniques; Isoenzymes; Macrophages; Male; Mice; Molar; Necrosis; Orthodontic Appliances; Osteoclasts; Periodontal Ligament; Phagocytosis; Pressure; Rats; Rats, Wistar; Root Resorption; Tartrate-Resistant Acid Phosphatase; Time Factors; Tooth Movement Techniques

The odontoclast, which is morphologically similar to osteoclast, is thought to play a major role in root resorption of deciduous teeth. High collagenolytic activity has been detected in the root resorbing tissue. In order to identify collagenase-producing cells and the role of collagenase in root resorption of deciduous tooth, in situ hybridization of collagenase mRNA in bovine root-resorbing tissue sections was performed using a digoxigenin-labeled, nonradioactive RNA probe. Collagenase mRNA expression was clearly observed in odontoclasts in addition to the macrophages, fibroblasts, odontoblasts, and cementoblasts. Multinuclear odontoclasts showed intense tartrate-resistant acid phosphatase (TRAP) activity. We also examined interleukin-1 (IL-1) mRNA expression in the root-resorbing tissue by in situ hybridization. IL-1 transcripts were found to be expressed in odontoclasts, fibroblasts, and macrophages suggesting that IL-1 might be an important factor for promoting root resorption. These results suggest that the collagenase produced by odontoclasts may play a key role in dentin collagen degradation in root resorption.

Topics: Acid Phosphatase; Animals; Blotting, Northern; Cattle; Cells, Cultured; Collagenases; Dental Cementum; Fibroblasts; In Situ Hybridization; Interleukin-1; Macrophages; Odontoblasts; Osteoclasts; RNA, Messenger; Root Resorption

This case report describes a radiographical, histological and histochemical study of an extracted mandibular tooth with progressive external root resorption. The cells which appeared to be responsible for the hard tissue resorption showed an intense acid phosphatase activity, similar to that of bone-resorbing cells. Some aspects on the etiology and pathogenesis of resorptive process that occurred in the present case are discussed.

Topics: Acid Phosphatase; Adult; Bicuspid; Dental Pulp Necrosis; Female; Humans; Mandible; Root Resorption

Human deciduous teeth undergoing physiologic root resorption were extracted and fixed with a mixture of formaldehyde and glutaraldehyde and processed for scanning (SEM) and transmission (TEM) electron microscopy, and for acid (ACPase) and alkaline phosphatase (ALPase) cytochemistry. The resorbant organ, rich in odontoclasts, cementoblasts, fibroblasts, and macrophages, formed prominent resorption lacunae in root dentin. SEM observations of resorption lacunae treated with trypsin solution showed islands of newly-formed cementum matrix in part of the resorbing dentin surfaces. Such cementum consisted of bundles of densely-arranged collagen fibrils and, in part, contained forming cementocytic lacunae and canaliculi. Active cementoblasts adjacent to odontoclasts on resorbing dentin surfaces showed cuboidal outlines and were characterized by the presence of numerous cisterns of rough endoplasmic reticulum, well-developed Golgi complexes, secretion granules, and many mitochondria. They sometimes formed a thin layer of cementoid and/or cementum matrix upon the resorbing dentin surface. These cementoblasts had ACPase-positive lysosomes in the cell bodies and exhibited intense ALPase activity along the plasma membranes of whole cell surfaces. These results suggest that, during root resorption, 1) active cementoblasts are present adjacent to active odontoclasts and 2) these cementoblasts are involved in remodeling the resorbing dentin surfaces.

Topics: Acid Phosphatase; Alkaline Phosphatase; Cell Membrane; Dental Cementum; Dentin; Fibroblasts; Histocytochemistry; Humans; Incisor; Microscopy, Electron, Scanning; Molar; Root Resorption; Tooth, Deciduous

The enzymes acid phosphatase (E.C. 3.133) and beta-glucuronidase (E.C. 3.2.1.31) have been demonstrated in dentin-resorbing cells by means of histochemistry. Addition of specific enzyme inhibitros revealed that the acid phosphatase of these cells was sensitive to fluride, copper, and m?OLYBDATE BUT RESISTANT TO Tartrate. The same pattern of enzyme activity has previously been found in bone-resorbing cells.

Topics: Acid Phosphatase; Dentin; Glucuronidase; Humans; Root Resorption