A preliminary investigation of short-term cytokine expression in gingival crevicular fluid secondary to high-level orthodontic forces and the associated root resorption: case series analytical study

Background: Orthodontically induced iatrogenic root resorption (OIIRR) is an unavoidable inflammatory process. Several factors claimed to be related to the severity of OIIRR. Orthodontic forces cause micro-trauma to the periodontal ligament and activate a cascade of cellular events associated with local periodontal inflammation. The purpose of this split-mouth study were (1) to investigate the changes in cytokine profile in the gingival crevicular fluid (GCF) secondary to heavy orthodontic forces and (2) to compare the cytokine expression between participants showing high and low root resorption. Methods: Eight participants requiring maxillary first premolar extractions involved in this study. The teeth on the tested side (TS) received 225 g of controlled buccal tipping force for 28 days, while the contralateral teeth act as a control (CS). GCF was collected from both TS and CS teeth at 0 h (prior to application of force) and 3 h, 1 day, 3 days, 7 days and 28 days after the application of force, and analysed with multiplex bead immunoassay to determine the cytokine levels. Results: Statistically significant temporal increase was found in the TS teeth for tumour necrosis factor alpha (TNF-α) at 3 h and 28 days (p = 0.01). Interleukin 7 (IL-7) significantly peaked at the 28th day. Comparing cytokine profile for participants with high and low root resorption (>0.35 and <0.15 mm3, respectively), the levels of GM-CSF was significantly greater in low root resorption cases (p < 0.05). The amounts of root resorption which craters on mesial, distal surfaces and middle third region were significant in the TS teeth (p < 0.05). Conclusions: IL-7 and TNF-α (pro-resorptive cytokine) increased significantly secondary to a high-level of orthodontic force application. Significantly high levels of granulocyte macrophage colony-stimulating factor (anti-resorptive cytokine) were detected in mild root resorption cases secondary to high-level orthodontic force application. A future long-term randomised clinical trial with larger sample taking in consideration gender, age and growth pattern distribution would be recommended

Combined treatment modality for intracranial germinomas: results of a multicentre SFOP experience

Conventional therapy for intracranial germinomas is craniospinal irradiation. In 1990, the Société Française d'Oncologie Pédiatrique initiated a study combining chemotherapy (alternating courses of etoposide–carboplatin and etoposide–ifosfamide for a recommended total of four courses) with 40 Gy local irradiation for patients with localized germinomas. Metastatic patients were allocated to receive low-dose craniospinal radiotherapy. Fifty-seven patients were enrolled between 1990 and 1996. Forty-seven had biopsy-proven germinoma. Biopsy was not performed in ten patients (four had diagnostic tumour markers and in six the neurosurgeon felt biopsy was contraindicated). Fifty-one patients had localized disease, and six leptomeningeal dissemination. Seven patients had bifocal tumour. All but one patient received at least four courses of chemotherapy. Toxicity was mainly haematological. Patients with diabetus insipidus (n = 25) commonly developed electrolyte disturbances during chemotherapy. No patient developed tumour progression during chemotherapy. Fifty patients received local radiotherapy with a median dose of 40 Gy to the initial tumour volume. Six metastatic patients, and one patient with localized disease who stopped chemotherapy due to severe toxicity, received craniospinal radiotherapy. The median follow-up for the group was 42 months. Four patients relapsed 9, 10, 38 and 57 months after diagnosis. Three achieved second complete remission following salvage treatment with chemotherapy alone or chemo-radiotherapy. The estimated 3-year survival probability is 98% (CI: 86.6–99.7%) and the estimated 3-year event-free survival is 96.4% (CI: 86.2–99.1%). This study shows that excellent survival rates can be achieved by combining chemotherapy and local radiotherapy in patients with non-metastatic intracranial germinomas. © 1999 Cancer Research Campaig

Development of a 3D Collagen Model for the In Vitro Evaluation of Magnetic-assisted Osteogenesis

Abstract Magnetic stimulation has been applied to bone regeneration, however, the cellular and molecular mechanisms of repair still require a better understanding. A three-dimensional (3D) collagen model was developed using plastic compression, which produces dense, cellular, mechanically strong native collagen structures. Osteoblast cells (MG-63) and magnetic iron oxide nanoparticles (IONPs) were incorporated into collagen gels to produce a range of cell-laden models. A magnetic bio-reactor to support cell growth under static magnetic fields (SMFs) was designed and fabricated by 3D printing. The influences of SMFs on cell proliferation, differentiation, extracellular matrix production, mineralisation and gene expression were evaluated. Polymerase chain reaction (PCR) further determined the effects of SMFs on the expression of runt-related transcription factor 2 (Runx2), osteonectin (ON), and bone morphogenic proteins 2 and 4 (BMP-2 and BMP-4). Results demonstrate that SMFs, IONPs and the collagen matrix can stimulate the proliferation, alkaline phosphatase production and mineralisation of MG-63 cells, by influencing matrix/cell interactions and encouraging the expression of Runx2, ON, BMP-2 and BMP-4. Therefore, the collagen model developed here not only offers a novel 3D bone model to better understand the effect of magnetic stimulation on osteogenesis, but also paves the way for further applications in tissue engineering and regenerative medicine

The drum spring (DS) retractor: A constant and continuous force for canine retraction

Although much research has been undertaken on the rate of tooth movement, with different hypotheses having been put forward, the concepts of threshold, light, heavy and optimal forces are not still clear

Validation of two-dimensional measurements of root resorption craters on human premolars after 28 days of force application

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Physical properties of root cementum: Part 10. Comparison of the effects of invisible removable thermoplastic appliances with light and heavy orthodontic forces on premolar cementum. A microcomputed-tomography study

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The effect of fluoride administration on rat serum osteocalcin expression during orthodontic movement.

INTRODUCTION: Osteocalcin is a bone protein that has been used to mark bone turnover. The precise role of this protein in bone remodeling has not been fully elucidated; however, it was shown to be instrumental in the activation of osteoclastic bone resorption via its effect on osteoblasts. Fluoride influences bone growth by acting as a mitogenic agent for osteoblasts. In this study, we used a rodent model to determine the effects of fluoride administration on systemic osteocalcin during orthodontic tooth movement. METHODS: Thirty-two 8-week-old female Wistar rats were divided into 4 groups. The first experimental group (n = 10) was fed a normal laboratory diet and distilled water (MilliQ). The second experimental group (n = 10) had the same diet with the addition of fluoridated water. All animals in both groups had 100-g nickel-titanium coil springs secured to their mandibular incisors and left first molars to instigate orthodontic tooth movement for 14 days. The third (n = 6) and fourth (n = 6) groups were the controls. These animals did not undergo orthodontic tooth movement and were given fluoridated (100 ppm sodium fluoride) and nonfluoridated water ad libitum. Phlebotomy was performed via the lateral tail vein before placement of the orthodontic appliances, and final blood samples were obtained via cardiac puncture after the rats were killed 2 weeks later. Serum was isolated from the samples after centrifuging at each stage of phlebotomy, and an enzyme-linked immunosorbent assay (ELISA) was subsequently performed to determine osteocalcin levels in the various sample groups. RESULTS: Orthodontic tooth movement with high, continuous forces was found to have a positive, statistically significant correlation with serum osteocalcin expression in the rodent model. The use of fluoride as a variable was found to increase the mean osteocalcin concentration, but this was not statistically significant. CONCLUSIONS: Further understanding of the biological implications of increased osteocalcin expression requires additional research into the local expression of this protein in the gingival crevice during orthodontic movement

Physical properties of root cementum: Part 4. Quantitative analysis of the mineral composition of human premolar cementum

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Accuracy of linear and angular measurements on panoramic radiographs taken at various positions in vitro.

The accuracy of measurement of tooth length and angulation on dental panoramic tomograms (DPTs) is thought to be highly dependent on head positioning technique. A model representing the dentition and the functional occlusal plane was designed using an acrylic framework and stainless steel wires. The aim was to investigate whether varying the position of the model affects the linear and angular measurements on DPTs. Four different positions were investigated: initial position representing natural head posture (NHP) (T1); lateral right cant of the occlusal plane (T2); lateral left cant of the occlusal plane (T3); and tilting the occlusal plane up anteriorly (T4). On each DPT, four sets of measurements were recorded: (1) Vertical linear measurements of the stainless steel pins and ratio calculations of the 'crown' and 'root' segments (represented by the wire above and below the occlusal plane, respectively); (2) angular measurements of the pins relative to the occlusal plane; (3) angular measurements of the pins relative to a constructed reference line; and (4) angular measurements of pins relative to each other in the same segment. The results showed a significant error (P < 0.05) in all measurements when the occlusal plane was tilted up anteriorly by 8 degrees. A lateral cant of the occlusal plane by less than 10 degrees without an upward anterior rotation showed no significant effect on the measurements. This would suggest that there is some tolerance of variation in head position