Materials & Restorations

1. Materials & Restorations Dr S.E.Jabbarifar April 2009

2. Materials & Restorations Back to basics !

3. Topics we will cover today • Choice of materials • Their properties and uses • Their advantages & disadvantages • Why do restorations fail ? • Preserving tooth structure • Repairing old fillings • ‘Temporary or Provisional’ restorations

4. Choosing Materials • Lets look at the pros & cons & uses of these direct restoratives: • Amalgam • Composite resins • Glass ionomer • Resin modified glass ionomer • Poly acid modified resins (compomers) • Calcium Hydroxide • Zinc Oxide & Eugenol

5. Choosing Materials • Lets also look at the pros & cons & uses of these indirect restoratives: • Acrylic • Chrome Cobalt • Porcelain • Gold

6. Why do Restorations Fail ? • Poor Design • Wrong material used • Inadequate thickness • Margins in occlusion • Built-in errors cause caries, eg. Overhang • Inadequate retention • Porosity, poor packing or finishing • Pulpal damage, poor lining

7. Why do Restorations Fail • Subsequent Changes • Recurrent caries • Tooth fracture • Attrition, abrasion, erosion • Pulpal necrosis • Tooth movement or loss causes increase or changes to applied forces • Trauma • Exceed ‘working life’ or just wear out

8. Preserving Tooth Structure • Saving enamel • Minimal invasion dentistry • ART technique • Tunnel preps • Adhesive dentistry • Repairing old restorations

9. Preserving Tooth Structure • What are we trying to preserve? • Remember basic dental anatomy • Outer Enamel • Hard, inflexible • Prism structure • Inner Dentine • Softer, more flexible • Vital structure

10. Preserving Tooth Structure • Natural tooth structure is irreplaceable…. . • THINK HARD before you cut ! • Your replacement will never be as good  • The tooth will become weaker • You are reducing the patient’s options • There is more to go wrong in future • You will probably be shortening the life of this tooth, and possibly the WHOLE dentition  • Practice true ‘CONSERVATIVE’ DENTISTRY

11. Preserving Tooth Structure • Ideally, our restoration should mimic the natural tooth structure • GIC replaces Dentine • Softer, more flexible • Hydrophilic • Composite replaces Enamel • Hard, inflexible • hydrophobic

12. Saving Enamel Where do the enamel prisms run ? Can we leave unsupported enamel If so under what circumstances ? Where can we preserve enamel ? IncisallyPrevent class 3 turning to class 4 if possible Marginal ridgetunnel prep or sideways prep Interproximally Palatal approach to Class 3 Just enough for matrix on Class 2 Gingivally Conserve margin, keep supragingival

13. Minimal Invasion Dentistry • Removal of enamel caries • Removal of soft, heavily infected dentine • Restore with cariostatic, adhesive material • Consider ‘stepwise excavation’ & stabilization • AVOID • Removing sound tooth structure • Exposure of pulp • Remember the ART technique ?

14. Tunnel Prep • Used for small Class 2 lesions • Contact point and marginal ridge are preserved • Tooth strength • is retained • T shaped • access cavity

15. T shaped access Remove caries ? matrix Pack GIC Composite What about the interproximal enamel ? Tunnel Prep pulp 46 45

16. Sideways Prep Used for small Class 2 lesions Contact point and marginal ridge are preserved Buccal access cavity

17. Adhesive Dentistry • Eliminates the need to cut a retentive cavity • Can support unsupported enamel • Reduces need for extensive crown or bridge prep. • Eg -Maryland bridge • Can eliminate preparation completely • Eg –diastema closure, composite bridge • Prolongs the life of restorations, thus reduces the number of re-cuts • REMEMBER- • fillings never get smaller when they are replaced !

18. Repairing Old Fillings • fillings never get any smaller • each time you replace them….. • So think before you drill and refill • Can the old filling be repaired ? • Is there hidden caries • Is the whole structure compromised • Are the aesthetics poor If NO, consider repair rather than replacement

19. Methods of Repairing Old Fillings • Smoothing & polishing margins • Local patching • Veneering • Bonding, eg replacing lost cusp • Mechanical retention, • Fresh surface cutting, retentive slots, etching, sandblasting, pins • Chemical bond • Suitable adhesives

20. Temporary or Provisional • Temporary filling- short term only • Prevents ingress of food and saliva • Protects vital tooth structures • Prevents tooth movement • Allows healing of painful tooth • May need to be aesthetic (but not too good) • Patient must understand the need to return, and what will go wrong if they don’t

21. Temporary or Provisional • Provisional filling- medium term • Awaiting healing, perio, pulp, endo • Checking occlusal load / wear patterns • Testing appearance • Testing phonetics • Testing function • Trying raised occlusal position • Patient must understand the need to for regular review and reassessment, and what will go wrong if their treatment is not completed.

22. Temporary / Provisional Materials • Temporary Filling • ZnO Eugenol, • Cavit • Temp Bond in acrylic or polycarbonate crown • Provisional filling • GIC • Acrylic • Composite • Choose your words, temporary or provisional • This will affect your patient’s expectations

23. Materials & Restorations • That's all folks • Thanks for listening • You’ve been a great audience