Pulpal considerations


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Pulpal considerations

  2. 2. ADHESIVE SEALERS  e.g: adhesive bonding systems-resin luting cements-GI luting cement  Provide chemical bond  Varnishes reduce but don’t eliminate microleakage around amalgam  High copper amalgam  Comparable in short term(24hrs to 14days)  Leakage increase: margin on dentin/cementum- 1month to year (long term=caries)  Drawbacks: pooling of resin(x-ray artifact/perio prob)-incorporation to amalgam/loss of strength- more tech sensitive than varnish PardisTarighi
  3. 3. PHYSIOLOGIC CONSIDERATIONS 1-RDT:  No material provides better protection  Role :Buffering-insulation  Single most important factor inprotecting pulp  Conservation better than replacement 2-Causes of pulpal inflammation:  Bacteria or toxins (dental materials : mild &transitory)  Early enamel caries ¼ DEJ causes slight reaction (enamel permeability)  Outward flow doesn’t prevent bacteria  Acid etch: tolerable if bacterial invasion in prevented  Rotary instruments : friction/dessication PardisTarighi 0.5mm=75% 1mm=90% 2mm 0.25-0.3
  4. 4. INSTRUMENTATION  Least effect: high speed-light force(1-3oz)-new bur- air coolant-water spray-least prep.  Frictional heat: burn lesions-abscess  Dessication: tolerable in limited areas- loss of dentinal fluid  Temperature rise: enamel vs dentine?/ pressure vs speed (low speeds)/ diamond vs carbide bur/ depth of prep.> full coverage:3-22%  New methods: laser(co2-Er:YAG-Nd:YAG-FEL)/ air abrasion (water coolant necessary)  Electrosurgery: intact enamel/ 0.4sec PardisTarighi
  5. 5. CAUSES OF PULPAL PAIN  inflammation>pressure on nerve ends  No inflammation> changes in outward flow speed>deformation of nerve ends PardisTarighi
  6. 6. CAUSES OF THERMAL SENSITIVITY  Theory of thermal shock (diffusivity) >base fore metallic restorations-thickness :0.5-0.75mm-E.M)  Theory of pulpal hydrodynamics (gap-volume and flow of outward fluid due to density/diameter/permeability) > effective sealing- integrity of interface PardisTarighi 6months max even with no base 50% 24hrs/78% mild almost always disappears within 30 days
  7. 7. CAVITY SEALERS,LINERS AND BASES Sealer • prevention of leakage at interface- coating all walls : a-varnish (natural/synthetic) b-adhesive sealer (seal&bond) Liner • minimal thickness- only near pulp wall- physical barrier and/or therapeutic effect(fluoride-antibacter) Base • replace missing dentin or block out undercuts PardisTarighi
  8. 8. CAVITY SEALERS  Kidd : microleakage= passage of bacteria-fluids- molecules-ions along the interface  Leads to : secondary caries-marginal discoloration- pulpal pathosis  Causes of clinical failures of restorations : sec. caries- marginal gap/fracture- discoloration PardisTarighi
  9. 9. VARNISHES  Natural gum (copal) , a rosin or synthetic resin dissolved in acetone,chloroform,ether  A thin protective film of 2-5μ  No thermal insulation  2applications  Reducing dentin permeability by 69%  Reducing microleakage 4-6months  Under ZPC crown cementation PardisTarighi
  10. 10. LINERS  Ca(OH)2  Not all formulations have stimulatory effect on pulpoblasts  Reparative dentin assisted rather than stimulated  Antibacterial/anti inflammatory action- release G.F from dentin>healing  Conventional: poor physical properties-high solubility-lower E.M  Light activated : better properties PardisTarighi
  11. 11. LINERS  Glass ionomer o Chemical bond-fluoride release o Decreases interfacial bacterial penetration (fluoride- low pH- metal cation) o Acidic for 24hrs o Conventional : reduced gap-higher E.M-lower resistance to acid etch o Bonded base technique (open sandwich provides better seal due to increased strain capacity because of delayed set) PardisTarighi
  12. 12. BASES  ZOE-ZPC: excellent thermal insulation-physical properties but not adhesive  GI (conventional) PardisTarighi
  13. 13. GUIDELINES FOR BASING-LINING-SEALING  Don’t remove sound tooth structure to provide space for base  Bases for buildup materials but for if for amalgam or composite restorations: minimal extent  Min. thickness of liner  Adhesive sealer under amalgam? PardisTarighi
  14. 14. PULP CAPPING  Endodontic treatment designed to maintain the vitality of the endodontium  1-vital pulp/no spontaneous pain 2-no lingering pain after hot/cold stimulus 3-no PA lesion 4-bacteria excluded  Indirect P.C prefered  Monitoring for several months PardisTarighi
  15. 15. DIRECT PULP CAP  Ideal condition= bacteria free  Aged pulps : increased fibrosis and decreased blood supply  Type/extent of exposure-bleeding amount  Only when: small mechanical exposure of healthy pulp-rubber dam isolation and adequate hemostasis PardisTarighi
  16. 16. INDIRECT PULP CAP  X-ray deep caries-no spontaneous pain-normal vitality test  Spoon excavator or large round bur,low speed handpiece  Wet(soft,amorphus) dentin removed- dry, fibrous demineralized dentin leaved(moderate resistance to gentle scraping)  Caries-disclosing dyes: caution for deep dentin PardisTarighi Delay indirect restorations 4-6months Do not remove IPC after removing temporary restoration
  17. 17. DENTIN BONDING VS CA(OH)2 AS DPC  After smear layer removal pulpal tissue and adhesive resin are compatible for 90days  Faster dentin bridge with Ca(OH)2  Toxic components rapid release  In bacteria free environment>successful capping with bonding  Imperfect seal (nanoleakage in hybrid layer-collagen hydrolysis)  Lower bond strength to carious dentin  Less intertubular dentin in deep lesions  Bond degredation  Acid etch: increase dentinal fluid flow-foreign body reaction- increased bleeding  Resin components inhibit T lymphocytes  QTH temperature(20sec=25.2˚c)/11.2 irreversible damage PardisTarighi
  18. 18. CALCIUM HYDROXIDE SHORTCOMINGS  Break down in acid etching  Dissolution under leaking restoration  Interfacial failure in amalgam condensation  Tunnel defect in reparative dentin PardisTarighi
  19. 19. FUTURE OF DIRECT PULP CAPPING MATERIALS  Hydroxyapatite as scaffold for dentin formation  BMP-BSP  MTA(tricalcium silicate/aluminate/oxide-silicate oxide) : high pH- compressive strength comparable to reinforced ZOE-radiopaque-antibacterial- biocompatible PardisTarighi
  20. 20. ANTIBACTERIAL EFFICACY OF RESTORATIVE MATERIALS  Amalgam: copper-mercury-zinc-silver-chloride components/effective against: S mutans, A viscous, lactobacillus spp Marginal seal improves with time(acidic environment/ low oxygen concentration/corrosion products)  GI  Resin composites (some resin components/Glutaraldehyde) PardisTarighi