orthodontic tooth movement / fixed orthodontic courses by IDA

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats. Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics, Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call 0091-9248678078

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0rthodontic tooth movement :

0rthodontic tooth movement INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com

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Based on current understanding as we apply orthodontic force on tooth following changes in gross occurs Primarily, alteration in the blood flow which results in reduced oxygen level at compressed area and might be an increased oxygen level at tension side. www.indiandentalacademy.com

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2. Secondly, generation of Piezo electric signal as now stated more appropriately as bioelectric potential in the form of small voltage of current which is released due to bending of bone and deformation of crystal structure. www.indiandentalacademy.com

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3. Thirdly, possibility of release of neuro transmitters (example Substance P, Vaso intestinal polypeptide VIP) on account of physical distortion imposed by peripheral forces on paradental tissues such as nerve fibers and terminals www.indiandentalacademy.com

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Thus the primary stimulus such as that of orthodontic force may elicit its response to cell of PDL and bone in the form of release of Bioelectric signals produced on account of bone bending Chemical mediators such as prostaglandins, cytokines, Nitric oxide (NO) etc., Release of neurotransmitters. www.indiandentalacademy.com

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It has been proved that cells in PDL and bone cells posses receptors for these substances (i.e. primary stimulus) and all these are highly interacting and interconnected. www.indiandentalacademy.com

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Primary stimulus Acts on Pdl and bone cells Interaction between these cells leads to Transient increase in the intracellular levels of second messengers CAMP IP3 Ca++ www.indiandentalacademy.com

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Secondary messenger Nucleus Takes signal to In the nucleus of each cell different second messengers account for the differential patterning, protein synthesis and Gene expression. Recently identified Immediate Early Gene expression include Cfos, Cjon mRNA, egr-I, SP1 growth differentiation factor 9B, extracellular GLA protein. www.indiandentalacademy.com

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These transcription factors can produce either cellular proliferation or cellular differentiation leading to osteoblastic bone formation or osteoclastic bone resorption. www.indiandentalacademy.com

ROLE OF PROSTAGLANDINS IN MEDIATING OTM :

ROLE OF PROSTAGLANDINS IN MEDIATING OTM Arachidonic acid can be released either by phospholipidases activated by direct cellular damage or by any nondestructive perturbation of the membrane, be it physical, chemical, hormonal or neuro hormonal. Prostaglandins can also be termed as local hormones functioning to co-ordinate effects of those other hormones which induce prostaglandin synthesis and Prostaglandins function through G-protein linked receptors to elicit their cellular effects. www.indiandentalacademy.com

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Classically Prostaglandins as one of the mediators of inflammation cause an increase in intracellular CAMP and Calcium accumulation by Monocytic cells which then modulates and activates osteoclastic activity. Klein and Riasz in 1970 reported first time the involvement of Prostaglandins in OTM. www.indiandentalacademy.com

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Recent studies indicate that Prostoglandins increase the number of Osteoclasts as well as stimulate Osteoblastic cell differentiation and new bone formation . www.indiandentalacademy.com

CYTOKINES & GROWTH FACTORS IN OTM :

CYTOKINES & GROWTH FACTORS IN OTM Cytokines secreted by leukocytes may interact directly with bone cells or indirectly, via neighboring cells, such as monocytes/macrophages,lymphocytes and fibroblasts, through their production of cytokine, or a variety of Growth factors. Cytokines released have multiple activities, which include bone remodeling, bone resorption, new bone deposition. www.indiandentalacademy.com

Prominent cytokines:

Prominent cytokines Interleukin I, IL-6, Tumor necrosis factor, Granulocyte- macrophage colony stimulating factor (GM-CSF) Macrophage colony stimulating factor (M-CSF ). www.indiandentalacademy.com

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Growth Factors are also released during inflammation and repair by the cells of PDL and bone. Another theory stated that the growth factors may secreted by bone cells and stored (bound to bound matrix) www.indiandentalacademy.com

Growth Factors :

Growth Factors Fibroblast Growth Factor (b FGF & a FGF), Insulin like Growth Factors (IGF – I, IGF – II), Transforming Growth Factor (TGF), Platelet Growth Factor (PDGFS), Bone Morphogenic Proteins (BMP) www.indiandentalacademy.com

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VEGF ( recombitent human vascular endothelial Growth Factor) has shown to stimulate macrophage colony stimulating factor, thereby enhancing number of osteoclasts and thus increased rate of OTM. www.indiandentalacademy.com

DETECTION OF MECHANICAL STRAIN BY BONE CELLS :

DETECTION OF MECHANICAL STRAIN BY BONE CELLS orthodontic force DETECTION OF MECHANICAL STRAIN Initial step is Three theories have been suggested on how these cells sense mechanical strain Strain Released potentials Activation of Ion channels Extra cellular Matrix & cytoskeleton reorganization www.indiandentalacademy.com

A) STRAIN RELEASED POTENTIALS :

A) STRAIN RELEASED POTENTIALS Application of small bending forces to bones is known to produce flow of interstitial fluid, through the canalicular network, generating streaming potentials. Osteocytes are more sensitive to mechanical stress than osteoblasts which are more sensitive than fibroblasts. www.indiandentalacademy.com

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Application of forces to bone results in several potential stimuli to bone cell function, Hydrostatic pressure Direct cell strain, Fluid flow Electric fields resulting form electro-kinetic effects accompanying fluid flow. induced shear stress www.indiandentalacademy.com

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Events affecting osteocytes Activates osteoblasts Activates osteoclasts or www.indiandentalacademy.com

B) ACTIVATION OF ION CHANNELS :

B) ACTIVATION OF ION CHANNELS Ion Channels are tunnel shaped proteins that cross the width of cell membrane and serve as selective conductive pathways for ions that cross the membrane as well as membranes surrounding intracellular organelles. www.indiandentalacademy.com

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Ion channels can be divided in to groups depending upon type of stimulus needed to activate the channel . Major groups are Voltage gated Ligand gated Mechanosensitive (stretch) ion channels. Response to changes in transmembrane potential. specific ligands that may attach to the cell membrane near channel opening. react to structural perturbations. www.indiandentalacademy.com

EXTRACELLULAR MATRIX & CYTOSKELETON REORGANIZATION. :

EXTRACELLULAR MATRIX & CYTOSKELETON REORGANIZATION . The macromolecules which make up the ECM include collagen & glycose amino glycans. These macromolecules are secreted at local levels by cells, particularly fibroblast in the PDL & osteoblast in the bone. The matrix metallo proteins (MMPS) represents major class of enzymes responsible for ECM metabolism. www.indiandentalacademy.com

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Thank you www.indiandentalacademy.com For more details please visit www.indiandentalacademy.com

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