STENCILDENT

 ELASTOMERIC IMPRESSION MATERIAL  PART 2 ADDITION SILICONE: AVAILABLE AS : 1)LIGHT 2)MEDIUM 3)HEAVY 4)PUTTY VISCOSITIES: PASTE: 2 equal size collapsible tube Cartridge:use with gun Putty jar Base paste : 1)Poly methyl hydrogen siloxane 2)Other siloxane pre-polymer 3)Hybrid silicone 4)Filler CATALYST PASTE : 1)Polydimethylsiloxane 2)Platinum salt activator 3)Palladium 4)Retarder  5)Filler  SETTING REACTION: Addition reaction No by product  Cross linkage between vinyl terminated silicone with silane terminated silicon  2nd reaction: Moisture +residual hydride Hydrogen gas is formed  Addition noble metal (platinum or palladium )to component that act as hydrogen absorber HYDROPHILIC SILICONE : Addition of surfactant  Advantage : Decreases air bubble in gypsum , Better wetting of soft tissue Disadvantage: Difficult to electroplate  Character: No by product  More dimensional stable Addition of surfactant turn to hydrophilic  ADVANTAGE: Clean,pleasant easily seen margin elasticity pour repeat

  ELASTOMERIC IMPRESSION MATERIALS  - PART 1  ELASTOMERIC :Rubber -like polymers that shows as elastic behaviour at the time of load application  These polymer molecules have weak interaction in between (Van der wall forces) They have tied together in 3D network  4 ELASTOMERIC IMPRESSION MATERIALS: 1)POLYSULFIDE 2)CONDENSATION -POLYMERIZATION SILICONE 3)ADDITION-POLYMERISATION SILICONE 4)POLYETHER   1)POLYSULPHIDE: 1st material introduced also known as mercaptan/thiokal Collapsible tubes : Base: White colour Catalyst: Brown,grey  VISCOSITIES: Heavy Medium Putty BASE : Low molecular weight polysulphide Filler (Titanium dioxide) plasticizer(Dibutyl phthalate) Accelerator(0.5% Sulphuric acid ) CATALYST: Lead oxide Filler (Titanium dioxide) Plasticizer(Dibutyl phthalate) Retarder(Oleic acid and Stearic acid) Condensation polymerisation: Mercaptan+lead dioxide  = polysulphide +water CHARACTER: Water by product +polymerisation shrinkage =dimensional changes Water could cause air bubble in st

  HUMAN IMMUNODEFICIENCY VIRUS  HUMAN -It can live only in human IMMUNODEFICIENCY -Damages the immune system of people it infects  VIRUS -Retrovirus (RNA) MORPHOLOGY: Spherical enveloped virus diameter :90-120 nm composed of 2 copies of positive single stranded RNA enclosed by conical capsid composed of viral protein p24 RNA genome consist of 9 gene  3 genes :gag,pol,env contain information needed to make the structural protein for new virus particle CAPSID : There are 3 enzyme required for HIV replication  REVERSE TRANSCRIPTASE INTEGRASE PROTEASE MATRIX: Composed of viral protein p17 surrounds the capsid  ensuring integrity of virion particle surrounded by phospholipid spikes 2 units -gp41 and gp120  PATHOGENESIS: 1)HIV attachment to host CD4 cell 2)Reverse transcriptase makes DNA from the virus RNA 3)Integration into host cells nucleus 4)Reproduction of viral components 5)Assembly of new HIV viruses 6)Virus release by budding (enzyme -protease) 7)Viral replication ,fusion,integrase 8

  DENTAL IMPLANT  A dental implant is a material /device in and or on oral tissue to support an oral prosthesis PARTS OF AN IMPLANT  : ABUTMENT- Support crown,provide retention IMPLANT BODY-Placed in bone HEALING SCREW-Prevent growth of tissue at edge of implant HEALING CAP-Maintenance of tissue  CHARACTERISTICS OF IMPLANT : 1)Sterile 2)Highly biocompatible 3)Should have primary stability 4)Should have adequate loading at time of healing 5)It should have surface configuration 6)It should consist of 2 parts :  a)Favour bioadhesion b)Non-adhesion  CLASSIFICATION: A)MATERIAL USED : 1)METAL AND ALLOY :Titanium and its alloy ,stainless steel 2)CERAMIC:Made of carbon with stainless steel 3)POLYMER AND COMPOSITE:Polymethylmethacrylate,polytetrafluorethylene B)BIOLOGICAL RESPONSE: 1)BIOTOLERANT : Gold Cobalt-chromium Not easily rejected when implanted in living tissue 2)BIOINERT: Titanium Allow close opposition of bone 3)BIOACTIVE: Bioglass Material that allow formation of bone onto their surf

ANGIOTENSIN CONVERTING ENZYME INHIBITOR COVID -19 (CORONAVIRUS 2019 DISEASE)a current pandemic infection caused by   RNA virus  Its mainly transmitted by droplet generated when an infected person coughs,sneezes or inhales. Symptoms:fever ,dry cough,tiredness.  Less common symptoms :headache,sore throat,diarrhoea,loss of taste or smell. Even if you notice mild symptoms don't hesitate to ask your doctor.  Get vaccinated at your chance  Getting vaccinated is very important to save us as well as your close ones , to learn more about herd immunity and its importance do check it out through this link  HERD IMMUNITY ANGIOTENSIN CONVERTING ENZYME INHIBITOR CAPTOPRIL: Dipeptide ace inhibitor Orally active Prototype drug Sulfhydryl containing dipeptide surrogate of proline  Abolish pressor action of angiotensin 1 without affecting angiotensin 2 Increase plasma kinin level : responsible for cough ,angioedema,hypotensive action. Decrease blood pressure is seen more in sodium depleted subject a

 RETICULOENDOTHELIAL SYSTEM Reticuloendothelial system is also known as mononuclear phagocytic system FORMATION: Bone marrow ,monocyte circulate in blood for 3 days they attain maturity,ability to phagocytose gets converted to macrophage -tissue macrophage gets scattered in different body parts and collectively called "tissue-macrophage system'. FOUND IN: 1)Endothelial lining of vascular and lymph node 2)Connective tissue and some organ like spleen ,liver,lungs,lymph node etc. CLASSIFICATION: 1) FIXED RETICULOENDOTHELIAL CELLS 2)WANDERING CELL  1) FIXED RETICULOENDOTHELIAL CELLS: Location- tissue Found in : Connective tissue : serous membrane of pleura Endothelium of blood of sinusoid; liver,spleen,lymph node Reticulum; spleen,lymph node  Central nervous system :microglia Lungs: alveoli of lungs  2) WANDERING CELL: A)IN BLOOD: NEUTROPHIL MONOCYTE B)IN SOLID TISSUE  Only during emergency Connective tissue and other organs come to play  FUNCTION: 1)Role in inflammation and heali

  BIOMEDICAL WASTE MANAGEMENT IN DENTISTRY BIOMEDICAL WASTE : Biomedical waste is defined as any type of waste generated in : Diagnosis Treatment Immunisation of human being /animal in a) research,b)production of biological products  It also includes waste coming out of medical treatment given at home  UNIVERSAL PRECAUTION: To minimise the infection in medical laboratory workers and health care personnel 1) Gloves: while handling blood and body fluid specimen 2) Laboratory coat /gown 3) All blood specimen placed in leak proof impervious bag for transportation to the laboratory  CATEGORIES OF BIOMEDICAL WASTE : 1) YELLOW- Infectious waste 2) RED- Contaminated waste  3) WHITE- Waste sharp including metal 4)BLUE - Sharps  WASTE GENERATED IN DENTAL PRACTISE: Anatomic,non-anatomic Silver containing waste used fixer solution and unused x-ray film Lead containing waste -lead apron,lead foils inside x-ray film Mercury containing waste -element mercury,scrap amalgam Chemical ,disinfectant a

 PIT AND FISSURE SEALANTS  Pit and fissure sealants  are advocated for: Susceptible pit and fissure area of posterior teeth Pediatric patient High caries risk patient  OBJECTIVE: Sealant is for resin to penetrate pit and fissure  Seal area against oral bacteria ,debris RESIN SYSTEM: Based on UDMA,bis-GMA POLYMERISED BY: Chemical activation -initiation,light activation UNFILLED RESIN: Colourless,tinted transparent material. FILLED RESIN; Available as tooth colored,white material SUCCESS DEPENDS ON: Obtaining ,maintaining intimate adaptation of sealant to tooth surface SEALANT MUST BE: Low viscous ,so that it flows into depth of pit and fissure TO ENHANCE WETTING ?RETENTION Tooth; 1st conditioned by etching with acid Effective therapy As long as sealant is well,no caries progression will occur Etch and rinse ,with primer and bonding agent PREVENTIVE -RESIN RESTORATION Conservative approach Minimal cavity preparation Enamel -dentin bonded composite restoration and sealant application High