Presentation on theme: "Materials & Restorations Dr S.E.Jabbarifar April 2009."— Presentation transcript:
Materials & Restorations Dr S.E.Jabbarifar April 2009
Materials & Restorations Back to basics !
Topics we will cover today Choice of materials Their properties and uses Their properties and uses Their advantages & disadvantages Their advantages & disadvantages Why do restorations fail ? Preserving tooth structure Repairing old fillings Temporary or Provisional restorations
Choosing Materials Lets also look at the pros & cons & uses of these indirect restoratives: Acrylic Acrylic Chrome Cobalt Chrome Cobalt Porcelain Porcelain Gold Gold
Why do Restorations Fail ? Poor Design Wrong material used Wrong material used Inadequate thickness Inadequate thickness Margins in occlusion Margins in occlusion Built-in errors cause caries, eg. Overhang Built-in errors cause caries, eg. Overhang Inadequate retention Inadequate retention Porosity, poor packing or finishing Porosity, poor packing or finishing Pulpal damage, poor lining Pulpal damage, poor lining
Why do Restorations Fail Subsequent Changes Recurrent caries Recurrent caries Tooth fracture Tooth fracture Attrition, abrasion, erosion Attrition, abrasion, erosion Pulpal necrosis Pulpal necrosis Tooth movement or loss causes increase or changes to applied forces Tooth movement or loss causes increase or changes to applied forces Trauma Trauma Exceed working life or just wear out Exceed working life or just wear out
Preserving Tooth Structure Saving enamel Minimal invasion dentistry ART technique Tunnel preps Adhesive dentistry Repairing old restorations
Preserving Tooth Structure What are we trying to preserve? Remember basic dental anatomy Outer Enamel Hard, inflexible Hard, inflexible Prism structure Prism structure Inner Dentine Softer, more flexible Softer, more flexible Vital structure Vital structure
Preserving Tooth Structure Natural tooth structure is irreplaceable….. THINK HARD before you cut ! Your replacement will never be as good Your replacement will never be as good The tooth will become weaker The tooth will become weaker You are reducing the patients options You are reducing the patients options There is more to go wrong in future There is more to go wrong in future You will probably be shortening the life of this tooth, and possibly the WHOLE dentition You will probably be shortening the life of this tooth, and possibly the WHOLE dentition Practice true CONSERVATIVE DENTISTRY
Preserving Tooth Structure Ideally, our restoration should mimic the natural tooth structure GIC replaces Dentine Softer, more flexible Softer, more flexible Hydrophilic Hydrophilic Composite replaces Enamel Hard, inflexible Hard, inflexible hydrophobic hydrophobic
Saving Enamel Where do the enamel prisms run ? Can we leave unsupported enamel If so under what circumstances ? Where can we preserve enamel ? Incisally Prevent class 3 turning to class 4 if possible Marginal ridge tunnel prep or sideways prep Interproximally Palatal approach to Class 3 Just enough for matrix on Class 2 Gingivally Conserve margin, keep supragingival
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 Removing sound tooth structure Exposure of pulp Exposure of pulp Remember the ART technique ?
Tunnel Prep Used for small Class 2 lesions Contact point and marginal ridge are preserved Tooth strength is retained T shaped access cavity
Tunnel Prep T shaped access Remove caries ? matrix Pack GIC Composite What about the interproximal enamel ? enamel ? pulp 4546
Sideways Prep Used for small Class 2 lesions Contact point and marginal ridge are preserved Buccal access cavity
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 Eg -Maryland bridge Can eliminate preparation completely Eg –diastema closure, composite bridge 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 !
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 there hidden caries Is the whole structure compromised Is the whole structure compromised Are the aesthetics poor Are the aesthetics poor If NO, consider repair rather than replacement
Methods of Repairing Old Fillings Smoothing & polishing margins Local patching Veneering Bonding, eg replacing lost cusp Mechanical retention, Mechanical retention, Fresh surface cutting, retentive slots, etching, sandblasting, pins Chemical bond Chemical bond Suitable adhesives
Temporary or Provisional Temporary filling- short term only Prevents ingress of food and saliva Prevents ingress of food and saliva Protects vital tooth structures Protects vital tooth structures Prevents tooth movement Prevents tooth movement Allows healing of painful tooth Allows healing of painful tooth May need to be aesthetic (but not too good) May need to be aesthetic (but not too good) Patient must understand the need to return, and what will go wrong if they dont
Temporary or Provisional Provisional filling- medium term Awaiting healing, perio, pulp, endo Awaiting healing, perio, pulp, endo Checking occlusal load / wear patterns Checking occlusal load / wear patterns Testing appearance Testing appearance Testing phonetics Testing phonetics Testing function Testing function Trying raised occlusal position 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.
Temporary / Provisional Materials Temporary Filling ZnO Eugenol, ZnO Eugenol, Cavit Cavit Temp Bond in acrylic or polycarbonate crown Temp Bond in acrylic or polycarbonate crown Provisional filling GIC GIC Acrylic Acrylic Composite Composite Choose your words, temporary or provisional This will affect your patients expectations This will affect your patients expectations
Materials & Restorations That's all folks Thanks for listening Youve been a great audience