Posts

Technique To Strengthen Ceramic

Image
  STRENGTHENING CERAMIC   Ceramic brittle matter and have low tensile strength - this makes it chip of at certain clinical condition. Therefore necessary to strengthen ceramic to increase longevity.  TECHNIQUE : 1)MINIMISING THE EFFECT OF STRESS CONCENTRATION: A)DESIGN OF PROSTHESIS: Select stronger and tougher ceramic  Grinding of surface of ceramic restoration should be minimised Avoid sharp line angle in tooth preparation  2)DEVELOPMENT OF RESIDUAL COMPRESSIVE STRESS: In post metal ceramic restoration : Metal should have more thermal coefficient of expansion than ceramic  Induce compressive stress this can withstand fracture  In all -ceramic : core ceramic have more thermal coefficient of expansion  3)MINIMISING NUMBER OF FIRING CYCLES: Repeated firing will result in : weaker and fragile ceramic If we reduce the number the number of firing we can strengthen ceramic  4)THERMAL TEMPERING : Ceramic is heated to a higher temperature ,once it reaches high temperature its quenched rapidly

LOCAL ANAESTHETICS- PHARMACOLOGY NOTES

Image
  LOCAL ANAESTHETICS Drugs that block peripheral nervous tissue when applied locally to nerve tissue in appropriate concentration,without loss of consciousness CLASSIFICATION: A) INJECTABLE : SHORT ACTING : Procaine  Chloroprocaine  INTERMEDIATE ACTING  Lignocaine  Prilocaine LONG ACTING Bupivacaine  Ropivacaine tetracaine  B) SURFACE ANAESTHETIC: Lignocaine  Cocaine Tetracaine MECHANISM OF ACTION : Primary mechanism of action: blockade of voltage gated sodium channel  local anaesthesia diffuse through cell membrane to bind the voltage sensitive sodium channel to prevent generation of action potential and conduction  DIFFERENTIAL BLOCKADE: 1)Autonomic (1st blocked )followed by sensory fibres,pain temperature ,touch ,pressure,vibration  Non myelinated fibres are blocked readily than myelinated  FEATURES OF LOCAL ANAESTHETICS: 1) It should have quick onset of action  2)It should not be irritating to skin and mucous membrane  3)Duration of action must be long enough to allow desired surge

HOW TO FIND ORAL SUBMUCOSAL FIBROSIS IN A PATIENT?

Image
  ORAL SUBMUCOUS FIBROSIS DEFINITION SIRSAT AND PINDBORGS : An insidious chronic disease affecting any part of oral cavity and sometimes pharynx,occasionally preceded by /associated with vesicle formation and always associated with juxta epithelial inflammatory reaction followed by hyalinisation of lamina propria with epithelial atrophy leading to stiffness of oral mucosa and progressive limitation in mouth opening In 1952,SG JOSHI coined the term oral submucous fibrosis  ETIOLOGY: Arecanut Chilli Genetic Autoimmunity  Composition of arecanut :alkaloid,flavonoid  predisposing factors :Nutritional deficiency  RATE OF INCIDENCE: 1984  - 4.5% 1990 - 7.6% 2000  - 13.33% PATHOGENESIS: Oral mucosa Betel quid habit  Constant irritation Chronic inflammation Activated t-cell and macrophage at the site  Transforming growth factor : Increases collagen production,Decreases collagen degradation Increased collagen production  FIBROSIS  Increase in cytokines (interleukin-6,interferon gamma,tumour nec

CATECHOLAMINES -SYNTHESIS,THERAPEUTIC ACTION

Image
  CATECHOLAMINES Neurotransmitter that take part in adrenergic transmission Catecholamines are synthesised from adrenal medulla ,from a specialised cell:chromaffin cell  The catecholamine includes : Adrenaline Nor -adrenaline Dopamine SYNTHESIS : 1)AT BLOOD : Phenylalanine 

DENTAL WAX-TYPES,INLAY WAX IN DETAIL NOTES

Image
  DENTAL WAXES  Low molecular weight ester of fatty acids derived from natural or synthetic components such as petroleum derivatives that soften to a plastic state at relatively low temperature  Wax has been a valuable commodity for over 2000 years  Carnauba wax:hardest,more durable  CLASSIFICATION OF WAXES: 1)ACCORDING TO ORIGIN: NATURAL : MINERAL :Paraffin,ceresin Carnauba,candelilla PLANT;Carnauba,candelilla INSECT:Beeswax ANIMAL:Spermaceti wax SYNTHETIC WAX Acra wax Aldo wax 2)ACCORDING TO USE AND APPLICATION: A)PATTERN WAXES  Inlay wax Casting wax Base plate wax B)PROCESSING WAX: Boxing wax utility wax Sticky wax C)IMPRESSION WAX Bite registration or corrective wax BOXING WAX Mode of supply : sheets  Uses:controls the thickness of the border ,preserves the extension UTILITY WAX: Composition:beeswax,petrolatum Mode of supply :sticks and sheets  Properties:soft at room temperature  Uses:to build up border of impression tray attaching a pontic of a bridge STICKY WAX Composition:yello

Leptospirosis -cause,pathogenesis,clinical features,diagnosis and treatment

Image
  LEPTOSPIROSIS  Leptospirosis is a zoonotic infection which is  caused by spirochete  ZOONOTIC DISEASE ? Zoonotic disease are infection that spread between animals and human  Examples :plague,ebola,rabies SPIROCHETE? Spiral shaped bacteria Helically coiled  Highly motile  Disease caused by spirochaetes: lyme disease,syphilis,borreliosis LEPTOSPIROSIS  Hook in ends Periplastic flagella  Leptospirosis -animal reservoir is rat (rodent ) Spread through rat urine contaminated in flood water More common in rainy season  LEPTOSPIRA SPECIES : PATHOGENIC -LEPTOSPIRA INTERROGANS FREE LIVING-LEPTOSPIRA BIFLEXA Leptospira dont stain well and are best seen in dark field microscopy with silver impregnation stain  PATHOGENESIS : Leptospira common in rodent (rat) ,also known as rat fever When a person who has cut or abraded skin walks in flood , Sewage water mixed with rat urine ;leptospira enter in and cause infection  Undergoes 2 phases: Phase 1- leptospiremia Phase 2-immune phase  Biphasic illness

Periodontal Screening And Recording -Periodontology easy notes

Image
 PERIODONTAL SCREENING AND  RECORDING  It has been developed jointly by the american academy of periodontology and the american dental association with the support of the procter and gamble company PROBE : WHO probe is used  It 0.5mm ball tip and colour coded from 3.5 to 5.5mm CODING SYSTEM : CODE 0 :  The probes coloured band remains completely visible  healthy and does not bleed on gentle probing  CODE 1:  Colour band completely visible in the deeper sulcus of the sextant bleeding after gentle probing is detected  CODE 2: Colour band completely visible,subgingival calculus defective margin are seen bleeding is there on probing  Treatment: Plaque and calculus removal,correction of plaque -retention margin of restoration and oral hygiene  CODE 3: Color band is partially visible  If 2 or more sextant score code 3,a comprehensive full -mouth examination and charting and indicated (3-4mm) CODE 4: Color band completely disappear (75mm) Asterisk* Abnormalities-furcation involvement ,tooth m