Opertive assignment 1
- 1. Importance of filler particles in clinical application of composite ? Generally: 1-Increase tensile strength- essentially preventing the restoration from cracking 2-Reduce polymerisation shrinkage 3-Reduce co-efficient of thermal expansion 4-Improved elastic modulus- allowing a greater strength to be applied without the elastic body changing shape 5-Provide radio-opacity 6-Control aesthetics- as mentioned varying types of filler produce different finishes eg small filler particles give a more polished finished 7-improve workability by increasing viscosity 8-reduction in water sorption , softening ,and staining 9-increase radiopacity and diagnostic sensitivity . 10-increase in abrasion resistance . 11-increasedfracture toughness. 12-Enhance physical and mechanical properties to the level of tooth tissue Clinical performance and durability . 13-Increase translucency .. 14-Improves handling properties . References: http://www.slideshare.net/deepthipramachandran/fillers-incomposite-resins important factors with regard to filler that determine the properties and clinical ppliation : amount of filler added : as filler content increases ,the fluidity reduces . high filler continent lower water . size of particles and distribution : to increase filler loading it is necessary to add filler in range of particle sizes . index of refraction for esthetic material ,should have translucency similar to that of tooth .
- 2. radiopacity: one of therreqirements of using a composite as a posterior restorative is that it should be radiopaque. Barium – zinc - boron – zirconium . hardness Composite type Microfill Clinical application -Enamel replacement in class III,IV,V restorations -minimal correction of tooth from and localized discoloration . Properties Polishability –Wear resistance –Water absorption –Radiopacity –Polymerization shrinkage -Posterior resin based composite restoration class V restoration -Dentin build up in class III,IV restoration Microhybrid -Posterior and anterior direct composite restoration -veneer -correction the tooth from discoloration . Packable -Posterior resin based composite restoration. Flowable -Pits and fissure restoration. - Liner in class I,II,IV restoration (dentin ) Radiopacity Polishability Physical properties –Polymerisation shrinkage Hybrid Note :+ positive property : performance acceptable - Negative property : performance unacceptable