Composite Resin Material Part 1 Dr. Nesrien Ateyah

History  Ideal esthetic material for conservative restorations has resulted in improvements in materials and techniques.  To improve the physical characteristics of the esthetic materials, they develop a polymeric dental restorative material reinforced with silica particles (1962) generally termed composites.

 Composites are presently the most popular tooth-colored materials and with acid etch technique (1952) represent major advances.

Composition Inorganic filler Organic resin matrix Filled (composite) resin restorative materials are all basically two-phase systems. Dispersed phase of Continuous phase high strength of polymeric ceramic particles matrix Inorganic filler Organic resin matrix Silane coupling agent

Inorganic Filler Lithium aluminum silicate Barium aluminum silicate Quartz, borosilicate glass Lithium aluminum silicate Inorganic Filler Barium aluminum silicate Strontium or zinc glass

Reduce the polymerization shrinkage. Inorganic Filler Reduce the polymerization shrinkage. Reduce the coefficient of thermal expansion. Provide higher strength , stiffness , FX. resistance  thermal dimension change.

Translucency matching tooth structure. Chemical inert ness Opaque to x-ray to help making a post operative diagnosis (radiopacity). Most material contain 70-80 percent filler by weight.

Organic Resin Matrix Mixing chemically reactive polymeric materials. After insertion  continuous ductile phase to bind dispersed filler particles together. This ductile resin act as a medium to transfer the stress b/w the particles (prevent distortion of the material). The resin systems are highly cross-linked , aromatic dimethacrylates. (BisGMA) diluted with less viscous co monomers , Initiator.

Silane Coupling Agent  wear resistance For a composite to have a good mechanical and physical properties, a strong bond must exist b/w Organic resin Inorganic filler matrix Silane coupling agent   strength of composite   solubility   water absorption Silane Coupling Agent  wear resistance

Inorganic Filler Types of Composite Divided into 3 types based primarily on Size Amount Composition Inorganic Filler

Types of Composites (cont’n) Early composite contained Large Large Micro fine Fine spherical irregular particles particles particles [0.04-0.2  m] [0.5-3  m] [20-30m] Blends (hybrid)

Types of Composites (cont’n) 1. Conventional 2. Micro fill Composites 3. Hybrid

Conventional Composites  Contain 75 to 80 % inorganic filler by weight ( 50 - 65 vol.)  Particle size range from 1 to 10 m, with the average of 3 m. Uses: Class IV and II

 extreme hardness of inorganic filler. Disadvantages:  Because of the :  large size and  extreme hardness of inorganic filler. It exhibits a rough surface texture then  surface discoloration  higher initial wear But  they have good physical and mechanical properties.

Micro fill Composites:  Designed to replace the rough surface characteristic of conventional composites with :  smooth  lustrous surface Colloidal silica particles 0.02 - 0.4m instead of large filler particles. Results in  smooth, polished surface   respective to plaque or staining.

( low modulus of elasticity ) Microfill Composites: (cont’n)  They have 35 to 60% inorganic filler by wt., so it cannot be heavily filled, because of greater surface area per unit volume of this microfine particles (20 - 50 vol.). Result in:  inferior physical and  mechanical properties Higher wear resistant clinically Uses: ( Anterior rest class III , V ) ( low modulus of elasticity )

Hybrid Composites:  Developed to combine the good physical and mechanical characteristics of conventional composites with the smooth surface of micro fill composites.  These materials have 70 to 80 % by wt., inorganic filler content (50 – 65 vol.).

Conventional Micro fill particles Hybrid Composites: (cont’n) The filler is a mixture Conventional Micro fill particles that have a smaller average particle size than conventional composites [0.5 - 3  m] and bigger than micro fill .

Hybrid Composites: (cont’ n) Due to the presence of sub-micron sized particles inter spread among the larger particles allows a smooth surface texture to be attained in the finished restoration.  They have good physical and mechanical characteristics. Uses: ( Anterior, posterior, IV )

Advantages of Composites: The physical properties of the composite resins are improved over those of certain other esthetic materials. 1) Solubility is not observed. 2) Water sorption is lower 3) Fluid exchange within the polymer decreased, this will promote Chemically Color Stability

1) It has greater capacity to resist masticatory stress. Advantages: (cont’n)  Mechanical properties of the filled resin also enhanced. 1) It has greater capacity to resist masticatory stress. 2) Surface hardness is higher (resistance to indentation)

3) Stiffness is improved (resistance to distortion) 4) Dimensional stability is improved. 5)Initial shrinkage on polymerization is reduced to 1/4 (less leakage)

 dimensional change during thermal cycling minimized Advantages: (cont’n) 6) Thermal coefficient of expansions is decreased by 60% (3x tooth structure) clinically  better adaptation to cavity walls and margins.  dimensional change during thermal cycling minimized resulting to  less marginal leakage

7) Thermal conductivity is quite low Advantages: (cont’n) 7) Thermal conductivity is quite low  resin has capability to insulate from thermal change.

2 - Conserve tooth structure Advantages of Composites Over Amalgam 1- Esthetic 2 - Conserve tooth structure 3 - Strengthening remaining tooth structure 4 -No corrosion 5 –No galvanic reaction

1- Less wear resistance in stress area. Disadvantages Over Amalgam 1- Less wear resistance in stress area. 2- Technique sensitivity 3- Higher coefficient of thermal expansion 4- Low modulus of elasticity

Indications: Indications: 1) Anterior restoration ( III , IV, V, VI ) 2) Posterior restoration ( I , II ) 3) Diastema closure 4) Preventive Resin Restoration 5) Veneering 6) FX. Of Anterior teeth Indications: Indications: 5) 4) FX. Of anterior teeth 7) Inlay and Onlay

Contraindications 1 - ISOLATION 2 - OCCLOUSION 3 – ROOT CARIES

 Restorative material manipulation  Moisture control  Cavity preparation  Restorative material manipulation  Moisture control The successful placement of a composite restoration requires meticulous attention to detail regarding

NK A TH U Y O

Indications: Indications: 1) Anterior restoration ( III , IV, V, VI ) Indications: Indications: 5) 4) FX. Of anterior teeth