Requirements of direct filling materials
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This document discusses the requirements of direct filling materials used in dental restorations. It states that direct filling materials are used for chairside restoration of teeth, as opposed to indirect materials which require a laboratory stage. The key requirements outlined are that direct filling materials must have appropriate rheological and setting properties to allow for easy handling during the restoration process. They must also demonstrate good chemical, thermal, and mechanical properties to withstand the conditions inside the mouth over many years. Direct filling materials offer advantages over indirect materials in that they are less time consuming, less costly, and more convenient for dentists to use.
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Requirements of direct filling materials
- 1. REQUIREMENTS OF DIRECT FILLING MATERIALS Professor Dr.Tahir Ali khan BDS, MDSc, MHR, FICD, Ph.D (Scolar) Vice Principal HOD: Science of Dental Materials
- 2. OBJECTIVES At the end of the lecture the student will know What are restorative materials Different types of restorative materials Classification of filling materials Why patients needs restorations Requirements of filling materials Advantages of direct filling materials over indirect filling materials
- 3. April 21, 2020 3 Restorative Materials โข Primers, Bonding agents โข Amalgams, Composites, GIC โข Ceramics, Denture Polymers
- 4. Restorative Material divided into Direct Restorative Material Indirect Restorative Material
- 5. Direct filling materials: for chair side restoration of teeth Indirect filling materials: for restoration of teeth involving laboratory stage
- 6. Classification of filling materials 1. Direct filling materials 2. Indirect filling materials 1. Direct filling materials A. Permanent B. Temporary A. Permanent filling materials Amalgam, Composite, GIC, Pure Gold, Silicate, Acryl ate
- 7. April 21, 2020 7
- 8. B. Temporary filling materials Zinc-Phosphate, Zinc-oxide, Zinc-polycarboxylate 2. Indirect filling materials Type 1 & 2 gold alloys Porcelain Composite
- 9. REQUIREMENTS OF DIRECT FILLING MATERIALS Why teeth need restorations? Dental caries External Trauma lost intentionally during tooth preparation to improve esthetics and mastication Wear Overzealous tooth brushing using an abrasive dentifrice Diet Working environment of habits of the patient
- 10. Lost of the tooth structure vary in Size, Shape and Location One wall, many walls and surfaces involvement One material is not needed and suited Some times we need to assess strength, abrasion resistance Otherthe hand appearance and adhesive properties
- 11. To assess the success or failure Durability is used which depends on physical, biological properties If the material is easy to handle, then it is acceptable to the operator
- 12. Rheological properties & setting characteristics Materials are supplied in 2 or more components (require mixing) Easy to mix Mixed materials easy to handle depends on Viscosity, Tackiness and setting characteristics (working and setting time) Materials should flow readily into the prepared cavity
- 13. Ideally mixed materials should not adhere to instrument Working time should be sufficiently long Setting time should ideally, be short Comfortable and convenient to the patient and dentist
- 14. Chemical properties To withstand the hostile environment of the oral cavity for many years without dissolving, degrading or eroding Must withstand large variations in pH and a variety of solvents (drinks, foodstuffs and medicaments) Should not undergo excessive corrosion or be involved in the development of electric currents, causing galvanic pain
- 15. Thermal properties Should be good thermal insulator to protect the dental pulp Thermal insulating properties are best characterized in terms of thermal diffusivity The value of thermal diffusivity should be ideally low Those material which has got high value of thermal diffusivity needing lining or base materials to protect pulp
- 16. The thermal expansion and contraction should match able to surrounding tooth substances Should have values of coefficient of thermal expansion similar to those of enamel and dentin Large mismatch values result in leakage
- 17. MECHANICAL PROPERTIES Vary considerably Depends on the type of tooth and particular surfaces being restored For larger cavities, a strong material with adequate abrasion resistance is required Should be able to resist plastic deformation or creep
- 18. In anterior region should be more abrasion resistance Should have high modulus of elasticity Adhesion Should be adhesive Minimizing the Micro-leakage
- 19. BIOLOGICAL PROPERTIES Should be harmless Should not cause irritation or toxicity to the pulp
- 20. ADVANTAGES OF DIRECT FILLING MATERIALS OVER INDIRECT FILLING MATERIALS Not time consuming Cost Convenient to use Historically three filling materials gain acceptance are Cohesive gold foil, dental amalgam and silicates Amalgam is still widely used
- 21. THANKS
Editor's Notes
- The parts of teeth which require replacement by a restorative material vary in size, shape and location in the mouth. Thus, at one extreme, it may be necessary to restore a large cavity which extends over the mesial, occlusal and distal surfaces of a molar tooth. An entirely different situation is the restoration of the corner of an incisor which has been lost in an accident. The requirements of materials used in these and other applications vary and it is not surprising that no single restorative material is suitable for all cases. For some situations the strength and abrasion resistance of the material may be the prime consideration. In other situations appearance and adhesive properties may become more important.
- Ideally materials should flow readily into the prepared cavity (materials needs little pressure, require packing under considerable pressure)
- The mechanical properties requirements of materials vary considerably depending on the type of tooth and particular surfaces being restored For larger cavities, a strong material with adequate abrasion resistance is required to withstand larger stresses developed in that region of the mouth When materials are subjected to direct masticatory loading they should also be able to resist plastic deformation or creep
- In anterior region (interproximal cavities) need to resist against abrasion The material should have high modulus of elasticity (marginal gap between materials and tooth may be lost if the material undergo creep) Adhesion The materials ideally should have good adhesive bond with the tooth substances, thus preventing the ingress of fluids and bacteria
- Biological properties The filling materials ideally should be harmless to both the operators and patients The specific requirements of the products relate to their effect on the pulp They should not either directly or indirectly cause irritation to the pulp not they should contain substances which are able to leach out and cause irritation