Composite Resin 3rd Year Dental Notes PDF

Composite Resin Dr. Khawlah Al-Othman BDS, MSc, ABGD, SBRD  ILOs List the indications and contraindications of composite restoration. List the advantages and disadvantages of composite restoration. Explain the initial clinical procedure prior to composite application. Describe the s...

Composite Resin Dr. Khawlah Al-Othman BDS, MSc, ABGD, SBRD  ILOs List the indications and contraindications of composite restoration. List the advantages and disadvantages of composite restoration. Explain the initial clinical procedure prior to composite application. Describe the steps of manipulation and application of composite. Explain the c-factor and its relation with polymerization shrinkage. History Composite was first Acid-etching introduced to the discovered by Dr. profession in 1955 by Dr. Michael Buonocore Raphael Bowen. almost at the same time. Definition Composite resin (GPT9): a highly cross-liked polymeric material reinforced by a dispersion of amorphous silica, glass, crystalline, or organic resin filler particles and /or short fibers bonded to the matrix by coupling agent. Composition Polymer(organic): Bis-GMA resin matrix. Filler particles (inorganic): Silica, glass, crystalline. At least 75% filler by weight. The smaller the filler size the better the mechanical properties of the composite. Silane coupling agents: Chemically bind fillers to the resin matrix. Photo-initiator: Camphorquinon, TPO. Indications of Composite Resin 1. Class I, II, III, IV, V, and VI restorations. 2. Foundations and core buildups. 3. Sealants and preventive resin restorations (conservative composite restorations). Indications of Composite Resin 4. Esthetic enhancement procedures: Partial veneers Full veneers Tooth contour modifications Diastema closures 5. Temporary or provisional restorations. 6. Periodontal splinting. 7. Luting of indirect esthetic restorations (when used in flowable form, or when heated to increase low). Contraindications of Composite Resin 1. Inability to obtain adequate isolation. 2. Occlusal considerations related to wear and fracture of the composite material. 3. Operator factors. Advantages of Composite Resin 1. Esthetics. 2. Conservative tooth preparation (mechanical retention usually not necessary). 3. Low thermal conductivity. 4. Universal use. 5. Adhesion to the tooth. 6. Repairability. Disadvantages of Composite Resin 1. Poor marginal and internal cavity adaptation, usually occurring on root surfaces as a result of polymerization shrinkage stresses or improper insertion of the composite. 2. Marginal deterioration over time in areas where no marginal enamel is available for bonding. 3. Time consuming to place. 4. More costly (compared with amalgam restorations). 5. More technique sensitive. 6. Occlusal wear in areas of high occlusal stress. Clinical Procedure A complete examination, diagnosis (including caries risk assessment), treatment plan, and informed consent. Clinical Procedure Pre-operative assessment of the occlusion Identify the occlusal contacts of the tooth to be restored and the occlusal contacts on adjacent teeth: To plan the restoration outline form To prevent an area of occlusal contact directly at a cavosurface/restoration interface To establish the proper occlusal contact on the restoration. The contacts are located on adjacent teeth provides guidance in knowing when the restoration contacts are correctly adjusted. Clinical Procedure Local Anesthesia Clinical Procedure Preparation of the Operating Site Clean the operating site with a slurry of pumice to remove plaque biofilm and superficial stains. Calculus removal with appropriate instruments. Clinical Procedure Shade Selection More important for anterior. Should be determined before teeth are subjected to any prolonged drying. Clinical Procedure Isolation of the Operating Site Critical. Rubber dam Isolation device (e.g., Isolite). Cotton rolls. estorative Technique Adhesive application Restorative Technique Acid etch 35-37 % phosphoric acid. 15-30 sec for enamel. Not more than 15 sec for dentin. Microporosity in E & D >> micromechanical retention. Chemical retention >> MDP. estorative Technique Rinse and dry 15 sec Enamel (frosty) Dentin (wet) Restorative Technique Total etch Self-etch estorative Technique Primer Hydrophilic monomer (HEMA). Solvent ( ethanol, acetone). Active application with microbrush 30 sec on D. Reapply >> Glossy. Air-dry 30 sec >> evaporate solvent. estorative Technique Bond Hydrophobic monomer (Bis-GMA, TEGDMA, UDMA). Initiatior (camphorquinon, TPO). Solvent. Active application with microbrush 30 sec on D. Reapply >> Glossy. Air-dry 30 sec >> evaporate solvent and spread the bond. Light cure 20 sec. Restorative Technique Light cure (LC) Light emiting diode (LED). Bluephase Third generation. Dual specrtum. Multi-wave length light cure all photoinitiator 385-515 nm (wave length). Irradiance =G2 up to 1200 mW/cm2. estorative Technique Composite application and LC Plastic Instrument (titanium/gold coated). estorative Technique Composite application and LC Increments of 2 mm, 20-40 sec LC for each increment. Oxygen inhibition layer: The sticky, resin-rich uncured layer that is left on the surface. When composite is light cured, oxygen in the air causes an interference in the polymerization resulting in the formation of an oxygen inhibition layer on the surface of the composite.. estorative Technique Configuration factor (C-factor) The ratio of bonded to unbonded surfaces in a tooth preparation and restoration. estorative Technique Polymerization shrinkage lymerization shrinkage of composite resins occurs mostly due the conversion of monomer into polymer chain in which e van der Waals forces are replaced by covalent bonds at pull the particles closer (Kaisarly and Gezawi., 2016). his leads to interfacial polymerization stresses, causing ap formation at the dentine-bond interface, increasing the risk f recurrent caries and consequently restoration failures Al Sunbul et al., 2016). The higher the C-factor = The higher the polymerization shrinkage stress estorative Technique To decrease Polymerization Shrinkage: 1. Increments application and LC of composite. 2. Soft curing , ramped lights, pulse curing, or simply holding the curing light some distance from the material for the initial exposure. 3. Use composite with high filler content. 4. Place thin layer of RMGI at the base. 5. Place thin layer of flowable composite. 6. Silorane-based composite ( shrinkage