STENCILDENT

  SEBACEOUS CYST  INTRODUCTION: SYNONYMS: EPIDERMOID CYST ,WEN  Etiology: acquired -retention cyst ,sebaceous cyst -obstruction  leads to accumulation of sebaceous material  Site:  Face Scalp Scrotum Back It does not occur in palm and sole cause sebaceous glands are absent  CLINICAL FEATURES: AGE:Early adulthood,middle age  Slow growing Shape:Hemispherical,Spherical  Central keratin filled- punctum indicate blockage of duct ,dark spot  20-30% cases punctum may not be seen  Surface :smooth,round border  Consistency :soft and putty,non-tender Sign of moulding Sign of indentation :pitting on pressure over the swelling Swelling mobile,except at the site of punctum Bony defect -absent Multiple sebaceous cyst may be associated with gardner syndrome TREATMENT: Incision and avulsion of cyst with the wall During dissection,cyst wall ruptures ,care should be taken to excise cyst wall ,cause there can be recurrence Small -excised with skin COMPLICATION: INFECTION: Injury,scratch may lead  to absc

  PERITONSILLAR ABSCESS ( QUINSY) 1)INTRODUCTION: TONSIL-Subepithelial aggregation of lymphoid tissue which forms a part of waldeyer's ring Its ovoid in shape Situated in lateral wall of oropharynx QUINSY- Collection of pus in peritonsillar space between capsule and superior constrictor muscle 2)ETIOLOGY: As a sequelae of acute tonsillitis De novo  Causative organism :  Streptococcus pyogenes Staphylococcus aureus  Anaerobic organism   3)MECHANISM : One of the crypts or crypta magna gets filled 

  CHERUBISM SYNONYMS: 1)FAMILIAL FIBROUS DYSPLASIA OF JAWS 2)DISSEMINATED JUVENILE FIBROUS DYSPLASIA  INTRODUCTION: JONES in 1933  coined the term cherubism  They resemble cherubs ( chubby cheeked little angel in renaissance painting) Autosomal dominant fibro-osseous lesion of jaws DEFINITION : Rare inherited autosomal dominant disease that causes bilateral enlargement of jaws giving the child a cherubic facial appearance Regress with age ,composed of giant cell granuloma like tissue and does not form bone matrix  PATHOGENESIS: Mutation in gene coding SH3BP2 located on 4P16.3  Autosomal dominant trait  Deficiency of sex steroids leads to reduction in osteoclast formation which leads to excess bone formation  At puberty, Osteoradiol+testosterone will cause increase in plasma concentration which results in localised increase in osteoclast  Thereby,stabilizes the disease  CLINICAL  FEATURES: Male's are more commonly affected than female ,100%penetrance in males,50-70% in females Age:

  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 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

  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 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