Amelogeneis Imperfecta

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Amelogeneis Imperfecta

  1. 1. Amelogenesis Imperfecta By: Shabeel PN
  2. 2. Amelogeneis Imperfecta  <ul><li>It is a heterogenous group of </li></ul><ul><li>hereditory disorders of enamel formation </li></ul><ul><li>affecting both deciduous & permanent </li></ul><ul><li>dentition. </li></ul><ul><li>prevalence is1 in 700 to 4000 with slight </li></ul><ul><li>male prediliction </li></ul><ul><li>Development of enamel has three major </li></ul><ul><li>stages:  (1) Elaboration of the organic matrix; (2) </li></ul><ul><li>Mineralization of the matrix; and  (3) Maturation of the </li></ul><ul><li>enamel </li></ul><ul><li>At least 14 subtypes related to above with a variety of </li></ul><ul><li>inheritance and clinical patterns </li></ul>
  3. 3. Modes of Mendelian Inheritance Associated withAI Autosomal Dominant Inheritance Can have male to male transmission. On average, half of the offspring of an affected individual will be affected. There is a 50% chance for the child of an affected individual to be affected. Affected males and females have similar clinical presentation . Autosomal Recessive Inheritance Unaffected parents will have affected offspring. On average, one in four offspring of carrier parents will be affected. More likely to occur when parents are related (consanguineous relationship). X-linked recessive inheritance Do not have male to male transmission. All daughters of an affected male are carriers. Half of the sons born to a carrier female will be affected. Affected males have more severe manifestations than females. Females can show no manifestations to severe manifestations due to lyonization. Females express only one X chromosome per cell with the other X chromosome becoming the bar body. If adequate numbers of cells express the X chromosome carrying the mutant allele, they will have varying degrees of the enamel defect.
  4. 4. Classification <ul><li>Witkop classification combines inheritance and clinical patterns </li></ul><ul><li>Type I hypoplastic(60-73%); generalized/localized, smooth/pitted/rough, AD, AR. X-linked </li></ul><ul><li>Type II hypomaturation(20-40%); pigmented/non-pigmented, diffuse/snow capped; AD, AR, X-linked </li></ul><ul><li>Type III Hypocalcified(7%); diffuse AD/AR </li></ul><ul><li>Type IV Hypomaturation-hypoplastic or hypoplastic-hypomaturation with taurodontism; AD </li></ul>
  5. 5. Hypoplastic Amelogenesis Imperfecta  <ul><li>Inadequate deposition of enamel matrix  </li></ul><ul><li>Generalized pattern – pinpoint sized pits scattered across surface of teeth </li></ul><ul><li>Localized pattern – horizontal rows of pits, linear depression or one large area of hypoplastic enamel </li></ul><ul><li>Autosomal dominant smooth pattern – smooth surface, enamel is thin, hard, and glossy </li></ul><ul><li>X-linked dominant smooth pattern – alternating zones of normal and abnormal enamel related to active X chromosomes </li></ul><ul><li>Rough pattern – thin, hard, rough enamel </li></ul><ul><li>Enamel agenesis – total lack of enamel formation </li></ul><ul><li>Teeth exhibit complete absence or thin layer of enamel. </li></ul><ul><li>  </li></ul>
  6. 6. Hypomaturation Amelogenesis Imperfecta   <ul><li>Enamel matrix laid down appropriately and begins to mineralize, but there is defective maturation of enamel’s crystal structure; normal shape but abnormal mottled, opaque white-brown color  </li></ul><ul><li>Pigmented pattern (AR) – surface enamel is mottled and brown  </li></ul><ul><li>X-linked pattern – deciduous are opaque white; permanent are yellow-white that darken with age  </li></ul><ul><li>Snow-capped pattern – zone of white opaque enamel on incisal or occlusal surface of the crown </li></ul><ul><li>Enamel can be pierced with an explorer tip with firm pressure ,teeth often show chipping of enamel from dentin surface. </li></ul>
  7. 7. Hypocalcified Amelogenesis Imperfecta   <ul><li>Enamel matrix laid down appropriately but no significant mineralization occurs (very soft enamel) </li></ul><ul><li>Normal shape but enamel soft and easily lost </li></ul><ul><li>Teeth yellow-brown to orange </li></ul><ul><li>Unerupted teeth and anterior open bite fairly common . </li></ul><ul><li>Enamel is normal in thickness ,but is soft and can easily removed by a blunt instrument. </li></ul>
  8. 8. Hypomaturation/hypoplastic Amelogenesis Imperfecta  <ul><li>Enamel hypoplasia combined with hypomaturation. </li></ul><ul><li>Hypomaturation-hypoplastic pattern – primary defect is enamel hypomaturation; mottled yellow-white to yellow-brown. </li></ul><ul><li>Hypoplastic-hypomaturation pattern – primary defect is enamel hypoplasia (thin enamel). </li></ul><ul><li>Both patterns seen in tricho-dento-osseous dysplasia syndrome </li></ul><ul><li>Taurodontism is the main feature. </li></ul>
  9. 9. Clinical and Hereditary Characteristicsof Four Main AI Types Autosomal dominant Enamel contrast normal to slightly > dentin, large pulp chambers Reduced, hypomineralized areas and pits White/Yellow- Brown mottled, teeth can appear small and lack proximal contact Hypomaturation/ Hypoplasia/ Taurodontism (Type IV) Autosomal dominant, recessive Enamel has contrast similar to or < dentin, unerupted crowns have normal morphology Normal thickness with enamel that often chips and abrades easily Opaque white to yellow-brown, soft rough enamel surface, dental sensitivity and open bite common, heavy calculus formation common Hypocalcified (Type III) Autosomal dominant, recessive, or X-linked Enamel has contrast similar to or > than dentin, unerupted crowns have normal morphology Normal thickness with enamel that often chips and abrades easily Varies from creamy opaque to marked yellow/brown, surface of teeth soft and rough, dental sensitivity and open bite common Hypomaturation (Type II) Autosomal dominant, recessive, or X-linked Enamel has normal to slightly reduced contrast/ thin Varies from thin and smooth to normal thickness with grooves, furrows and/or pits Crowns size varies from small to normal, small teeth may lack proxmial contacts, color varies from normal to opaque white – yellow brown Hypoplastic (Type I) Inheritance Radiographic Appearance Enamel Thickness Clinical Appearance Type
  10. 10. Clinical Features: <ul><li>Affect both dentition </li></ul><ul><li>Colour of tooth is chalky white-yellow or dark brown </li></ul><ul><li>Proximal contact points are mostly open while occlusal surfaces and incisal edges are severely abraded. </li></ul><ul><li>Sometimes enamel completely absent shows severe abrassion of dentin. </li></ul>
  11. 11. Clinical features: <ul><li>Rarely enamel looks normal with few grooves and wrinkles on the surface. </li></ul><ul><li>It does not increase susceptibility to caries </li></ul><ul><li>In mildest form of hypomaturation type the enamel is near normal in hardness and some white flecks are seen at incisal edges. Called “SNOW CAPPED TEETH” </li></ul>
  12. 12. Amelogenesis imperfecta at a glance………………
  13. 13. Radiographic features <ul><li>Thickness & radiodensity of enamel varies greatly </li></ul><ul><li>In hypoplastic type-R D of enamel>dentin </li></ul><ul><li>In hypomaturation type-R D of enamel=dentin </li></ul><ul><li>If present enamel mostly seen on tip of cusp and interproximal areas. </li></ul>
  14. 14. Histopathology: <ul><li>Hypoplastic type: lack of differentiation of ameloblast cells with little or no matrix formation. </li></ul><ul><li>Hypomaturation type: Alternation of enamel rod and rod sheath structures. </li></ul><ul><li>Hypocalcification type:Defective matrix structure and abnormal or sub normal mineral deposition . </li></ul>
  15. 15. Treatment of  Amelogenesis Imperfecta   <ul><li>Treatment of Hypoplastic AI Types </li></ul><ul><li>Treatment of Hypomaturation and Hypocalcified AI Types </li></ul><ul><li>Gingival Health Management in AI </li></ul><ul><li>Treatment of Dental Malocclusions </li></ul><ul><li>Depends on severity; Problems include aesthetics, sensitivity, vertical dimension, caries, open bite, delayed eruption and impaction </li></ul><ul><li>Where enamel is very thin, full coverage needed as soon as possible </li></ul><ul><li>Less severe cases, aesthetics are main consideration.  Full crowns or facial veneers </li></ul>
  16. 16. Treated Cases
  17. 17. Bibliography <ul><li>Shafer’s Oral Pathology : 5 th Edn </li></ul><ul><li>Oral & Maxillofacial Pathology –Neville,2 nd Edn </li></ul><ul><li>Essential of Oral Pathology –Swapan Kumar Purkait </li></ul><ul><li>The World Wide Web: </li></ul><ul><li>www.dent.unc.edu/research/defects.cfm </li></ul><ul><li>www.dental.mu.edu/oralpath/spresent/ amelogenesis .htm </li></ul><ul><li>www.rarediseases.org/search/rdbdetail_abstract.html </li></ul><ul><li>en.wikipedia.org/wiki/ Amelogenesis _ imperfecta </li></ul>
  18. 18. THANK YOU !!! <ul><li>By : </li></ul><ul><li>Dr Shabeel PN. </li></ul><ul><li>RDC </li></ul>

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