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All ceramic crown preparation seminar

all ceramic crown prepartion
esthetic crown
fixed prosthodontics

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All ceramic crown preparation seminar

  1. 1. Today: we will talk about all ceramic crown preparation.
  2. 2. DefinitionDefinition • Non metallic full coverage ceramic restoration . Restoring the prepared ant. Teeth functionally & esthetically
  3. 3. • Advantages Superior esthetic
  4. 4. Excellent translucency Good tissue response Conservative reduction of facial surface Appearance of restoration influenced by color of luting agent
  5. 5. DisadvantagesDisadvantages  Absence of metal substructure Reduced strength of the restoration  Significant tooth reduction is necessary on proximal & lingual surface  Difficulty in obtaining well fitting margin
  6. 6. * Not effective as retainer for fixed prosthesis * Wear observed on functional surface of natural tooth * Wear may occur on functional surfaces of natural teeth that oppose porcelain restoration •
  7. 7.  IndicationsIndications in ant. Teethin ant. Teeth ** Discolored toothDiscolored tooth ** Tooth with enamel defectsTooth with enamel defects ** Fracture teethFracture teeth ** Bilateral proximal decay with incisalBilateral proximal decay with incisal angle involved (class 4 ).angle involved (class 4 ). ** Unilateral proximal decayUnilateral proximal decay
  8. 8. • ** Excessive attrition toothExcessive attrition tooth ** at rampant cariesat rampant caries ** malformed and rotated teethmalformed and rotated teeth *functions:*functions: **All ceramic is used as foundationAll ceramic is used as foundation restorationrestoration ** for endodontically treated teeth tofor endodontically treated teeth to overcome esthetic problem associatedovercome esthetic problem associated with metal post and core systemwith metal post and core system
  9. 9. •ContraindicationContraindication ** With posterior teethWith posterior teeth ** young patientsyoung patients → large pulp,high epithelium→ large pulp,high epithelium attachmentattachment ** Deep or heavy bitesDeep or heavy bites Bad habits ( ex. nail biting )Bad habits ( ex. nail biting ) ** If occlusal load is unfavorableIf occlusal load is unfavorable ** At long span bridgeAt long span bridge ** when other more conservative rest. iswhen other more conservative rest. is indicatedindicated
  10. 10. PrecautionsPrecautions • Over tapered prepared cingulum → ↓ Resistance & Retention → exert wedge like force thus ↑ stress causing fracture •Horizontal surface at the junction of prepared fossa & lingual wall should be preserved → reduce stresses
  11. 11. • Lingual ridge of canine not completely reduced → ↑ rotational resistance
  12. 12. Facial reductionFacial reduction Placing depth orientation groove Depth of grooves should be 0.8 mm as at finishing become 1 mm Reduce the areas between grooves Two planes in preparation to provide adequate esthetics without affecting pulp . 1st plane is on incisal two third . 2nd plane is on one-third
  13. 13. * facial reduction should extend around the facial-proximal line angles & fade out on the lingual aspect of the proximal surface * end of flat end diamond forms shoulder finishline
  14. 14. Incisal reductionIncisal reduction • reduction 1.5 : 2 mm clearance to provide esthetic & adequate strength restoration • 45 degrees towards lingual surface • 3 depth grooves approximately 1.3 mm to allow additional loss during finishing • tooth structure between the grooves should be reduced • Incisal reduction should be perpendicular to the plane of incisal half of labial reduction
  15. 15. Lingual reductionLingual reduction Cingulum reduction is done by FootballCingulum reduction is done by Football shaped diamondshaped diamond  care should be taken to prevent over atcare should be taken to prevent over at the junction between cingulum & lingualthe junction between cingulum & lingual walwal ll A short lingual wall reduces the retentionA short lingual wall reduces the retention of the restorationof the restoration
  16. 16. Proximal reductionProximal reduction * The shoulder should be at least 1.0 mm wide * care should be taken to avoid undercuts at the junction of axial walls & the shoulder finish line
  17. 17. Finishing the preparationFinishing the preparation ** All axial surfaces should be smoothed usingAll axial surfaces should be smoothed using finishing stones & bursfinishing stones & burs ** Roundation of any remaining sharp lineRoundation of any remaining sharp line angles to avoid porcelain fractureangles to avoid porcelain fracture ** Uniform width of shoulder finish lineUniform width of shoulder finish line (approximately 1mm ) to resist forces directed(approximately 1mm ) to resist forces directed from the incisalfrom the incisal
  18. 18. prepared by :prepared by : Moataz AbodiefMoataz Abodief Mostafa El-SadicMostafa El-Sadic Nour MohammedNour Mohammed Waleed MohammedWaleed Mohammed Dentistry College ; Assiut UniversityDentistry College ; Assiut University thanksthanks