Third year bds paedodontics composite restoration

Third year bds

1. BY K. C ATHIRA COMPOSITES

2. INTRODUCTION COMPOSITION CLASSIFICATION OF COMPOSITES PROPERTIES OF COMPOSITES INDICATIONS CONTRAINDICATIONS ADVANTAGE DISADVANTAGE TYPES OF COMPOSITES INDEX CONCLUSION

3. INTRODUCTION In material science, a composite is a mixture produced from at least two of the different classes of materials, i.e., metals, ceramics, and polymers. Definition : "Dental composites are complex, tooth-colored filling materials composed of synthetic polymers, particulate ceramic reinforcing fillers, molecules which promote or modify the polymerization reaction that produces the cross-linked polymer matrix from the dimethacrylate resin monomers, and silane-coupling agents which bond the reinforcing fillers to the polymer matrix" Developed in 1962 by combining dimethacrylates (epoxy resin and meth- acrylic acid) with silinized quartz powder by Bowen (1963). 01

4. COMPOSITION 02 Major constituents Minor constituents Resin matrix Color modifiers Filler particle Inhibitors Coupling agent Activator - initiator accelerator system

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6. 04 I . Based on the resin matrix used A. Bis-GMA based B. UDMA based C. Silorane based II . Based on the type of cure A. Chemical cure B. UV light cured C. Visible light cured (VLC) D. Dual cure E. Tri cure F. Heat and pressure cured IV. Based on the filler particle size (Lutz and Phillip, 1983) (Most commonly used classifi cation) A. Conventional B. Microfilled C. Small particle D. Hybrid III. Based on the mode of curing A. Instant cure B. Soft cure 1. Ramped cure 2. Stepped cure 3. Oscillating cure 4. Delayed cure V. Based on the filler particle size Another more recent classification based on the size of the filler particles is as follows: A. Megafill —contains large individual particles B. Macrofill —contains macrofillers in the range of 10–100 mm C. Midifill —contains fillers in the range of 1–10 mm D. Minifill —contains minifillers in the range of 0.1–1 mm E. Microfill —contains microfillers within 0.01–0.1 mm F. Nanofill —contains nanofillers in the range of 0.001–0.01 mm CLASSIFICATION OF COMPOSITES

7. 1. Linear coefficient of thermal expansion (LCTE ) : It is the rate of dimensional change of a material per unit change in temperature. The closer the LCTE of the material is to the LCTE of enamel, the less chance there is for creating voids or openings at the junction of the material 2. Water absorption : When a restorative material absorbs water, its properties change, and therefore, its effectiveness as a restorative material is usually diminished. Materials with higher filler contents exhibit lower water absorption values. PROPERTIES OF COMPOSITES 05

8. 06 3. Wear resistance : It refers to a material's ability to resist surface loss as a result of abrasive contact with opposing tooth structure, restorative material, food boli , and such items as toothbrush bristles and toothpicks. Wear resistance of composite materials is generally good. 4. Surface texture : It is the smoothness of the surface of the restorative material. Microfill composites offer the smoothest restorative surface; hybrid composites also provide surface textures that are both esthetic and compatible with soft tissues. 5. Radiopacity : Esthetic restorative materials must be sufficiently radiopaque, so that the radiolucent image of recurrent caries around or under a restoration can be more easily seen in a radiography.

9. 07 6. Modulus of elasticity : It is the stiffness of a material. A material having a higher modulus is more rigid; conversely, a material with a lower modulus is more flexible. A microfill composite material with greater flexibility may perform better in certain Class V restorations than a more rigid hybrid composite. 7. Solubility : It is the loss in weight per unit surface area or volume due to dissolution or disintegration of a material in oral fluids, over time, at a given temperature. 8. Polymerization : Full polymerization of the material is determined by the degree of conversion of monomers into polymers, indicating the number of methacrylate groups that have reacted with each other during the conversion process.

10. 08 IndIcatIon Classes I, II, III, IV, V, and VI restorations. Preventive resin restorations Foundations or core build- ups Sealants. Cements (for indirect restoration) Esthetic enhancement procedures - Partial veneers - Full veneers Tooth contour modifications Diastema closure Periodontal splinting Temporary restorations

11. 09 CONTRAINDICATIONS If the operating site cannot be isolated from contamination by oral fluids. If all of the occlusal load will be on the restorative material. Restorations that extend onto the root surface may result in less than ideal marginal integrity.

12. 10 ADVANTAGES Esthetic Conservative of tooth structure removal Have low thermal conductivity Used almost universally Tooth preparation is simple Bonded to tooth structure Repairable

13. 11 DISADVANTAGES May have a gap formation Time-consuming Costly Establishing proximal contacts, axial contours, embrasures may be more difficult Technique sensitive Exhibit greater occlusal wear in areas of high occlusal stress Marginal leakage can occur

14. 12 1. HYBRID COMPOSITE RESINS: These composites are so called, because they are made up of polymer groups (organic phase) reinforced by an inorganic phase, comprising 60% or more of the total content. It is composed of glasses of different compositions and sizes. Properties: Available in wide range of colors Ability to mimic the dental structure, Less curing shrinkage, Low water absorption, Excellent polishing and texturing properties, Abrasion and wear very similar to that of tooth structures, Similar thermal expansion coefficient to that of teeth TYPE OF COMPOSITE

15. 13 2. FLOWABLE COMPOSITES: These are low-viscosity composite resins, making them more fluid than conventional composite resins. The percentage of inorganic filler is lower. Advantages : High wettability of the tooth surface, Ensuring penetration into every irregularity; Ability to form layers of minimum thickness, so improving or eliminating air inclusion or entrapment Radiopaqueness Availability in different colors. Drawbacks High curing shrinkage, Due to lower filler load, and weaker mechanical properties. Indication Class V restorations, cervical wear processes and minimal occlusal restorations or as liner materials in Class I or II cavities or areas of cavitated enamel.

16. 14 3. CONDENSABLE COMPOSITES: Condensable composites are composite resins with a high percentage of filler. Advantages Condensability (like silver amalgam), Greater ease in achieving a good contact point, Better reproduction of occlusal anatomy. Disadvantages Difficulties in adaptation between one composite layer and another, Difficult handling and poor esthetics in anterior teeth. Indication is Class II cavity restoration in order to achieve a better contact point.

17. 15 4. ORMOCERS A word originally derived from organically modified ceramic, were originally developed for science and technology. The organic polymers influence the polarity Ability to cross link, hardness, and optical behavior. The glass and ceramic components (inorganic constituents) are responsible for thermal expansion and chemical stability The polysiloxanes influence the elasticity, interface properties, and processing. Ormocers have a reduced polymerization shrinkage compared to hybrid composites.

18. 16 5. COMPOMER: The word "Compomer" comes from composite and glass ionomer. The material itself is a polyacrylic or polycarboxylic acid-modified composite. Compomer are composed of composite and glass ionomer components in an attempt to take advantage of the desirable qualities of both materials The fluoride release and ease of use of the glass ionomers and the superior material qualities and esthetics of the composites Compomer is most suitable for restorations in the deciduous dentition due to their low abrasion resistance

19. 17 6. SILORANE The name of this material class refers to its chemical composition from silox-anes and oxirans. This product class aims to have lower shrinkage, longer resistance to fading, and less marginal discoloration. The adhesion of streptococci observed on the surface of silorane restorations was low, may be because of its hydrophobic properties

20. 18 7. NANOCOMPOSITE Nanotechnology may provide composite resins with a dramatically smaller filler particle size that can be dissolved in higher concentrations and polymerized into the resin system. The molecules in these materials can be designed to be compatible when coupled with a polymer and provide unique characteristics (i.e. physical, mechanical, optical). Nanotechnology can, however, improve this continuity between the tooth structure and the nano-sized filler particle and provide a more stable and natural interface between the mineralized hard tissues of the tooth and these advanced restorative biomaterials.

21. 19 8. ANTIMICROBIAL COMPOSITE: Silver and titanium particles were introduced into dental composites, respectively, to introduce antimicrobial properties and enhance the biocompatibility of the composites.

22. 20 9. STIMULI RESPONSIVE COMPOSITE: Stimuli-responsive materials possess properties that may be considerably changed in a controlled fashion by external stimuli such as changes of temperature, mechanical stress, pH, moisture or electric or magnetic fields.

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27. Dental composites are complex materials composed of various components, offering a range of properties and advantages. Different types of composites, such as hybrid, flowable, condensable, ormocers , compomers, siloranes , nanocomposites, antimicrobial, and stimuli-responsive composites, cater to specific needs and applications. Understanding the characteristics, indications, and limitations of each type is crucial for effective use in dental restorations. By selecting the appropriate composite material, dentists can achieve optimal results, combining esthetics, durability, and patient comfort. As research and technology continue to evolve, dental composites will likely become even more sophisticated, offering improved performance and benefits for patients. CONCLUSION 25

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