Direct Composite Restorations - Midterms (Resto 2) PDF

LESSON 1: DIRECT COMPOSITE RESTORATIONS RESTO 2 1ST SEMESTER| 2024-2025 |DR. FILOTEO Shade Selection Insertion and Light curing – Done...

LESSON 1: DIRECT COMPOSITE RESTORATIONS RESTO 2 1ST SEMESTER| 2024-2025 |DR. FILOTEO Shade Selection Insertion and Light curing – Done before drying the tooth To place and light cure the composite incrementally to ensure maximum polymerization and to reduce Variation of Tooth Color polymerization shrinkage Translucency The higher the C factor, the higher the polymerization Thickness shrinkage stress Age, Fluorosis, Stains C factor Shades Bonded Tooth Surfaces Enamel shade - A1-5 Unbonded Tooth Surface Bleach shade - B1-3 Dentin shade - D1, D2, or A30 Class III, IV and V An enamel bevel is used on the facial cavosurface margin to provide Good lighting is necessary gradual color transition from the restoration to surrounding tooth Natural light is preferred structure for esthetics Selection should be made as rapidly as Lingual possible Facial enamel is conserved The entire shade guide should be near Shade matching is less critical the patient’s teeth Discoloration or deterioration of the restoration is less visible Initial Clinical Procedures Labial Local Anesthesia Carious lesion involves – Profound anesthesia contributes to a more comfortable and facial surface if teeth uninterrupted may result in reduction in salivation are irregularly aligned Preparation of the Operating Site – Clean the operating site w/ a slurry of pumice to remove Isolation of Operating Field plaque biofilm and superficial stains. Goals – Remove calculus if there is any – Prophy paste containing flavoring agents, fluoride acts as Moisture control contaminants and must not be used to compromise the Retraction adhesive procedure Patient safety Shade selection Different Methods of Isolation Rubber dam – Not important on posterior when compared to anterior Cotton roll – The shade of the tooth should be determined before teeth Mirror and saliva ejectors are subjected to any prolonged drying Throat shields Isolation of Operating Site High volume excavator Retraction cord – Isolation of tooth colored restoration is critical and can be accomplished w/ a rubber dam, an isolation device (e.g. isolite) Indirect Composite Restoration or cotton rolls/dry angles. Indirect Composite Restoration or Laboratory Other preoperative considerations: Processed Composite Preop Assessment of Occlusion Polymer glasses – Remember the location of the occlusal contacts of the tooth Filled polymers to be restored and the adjacent teeth Ceramic-optimized resins (ceromers) Extraoral curing by heat, pressure or light seems to improve their physical and mechanical Cavity Preparation Indications of Indirect Composites 1. Create access to faulty structure 1. Maximum wear resistance is desired 2. Removal of faulty structure 2. Achievement of proper contacts and contours would 3. Create convenience form for the restoration otherwise be difficult 3. Ceramic restorations are contraindicated because of cost or concerns with wear of opposing dentition MIDTERMS LESSON 1 TRINIDAD 1  LESSON 1: DIRECT COMPOSITE RESTORATIONS RESTO 2 1ST SEMESTER| 2024-2025 |DR. FILOTEO Contraindications of Indirect Composites Major turning points and events in dental bonding technologies: 1. Heavy occlusal forces 1960 2. Inability to maintain a dry field ○ Non bonded composites 3. Deep subgingival preparations ○ Buonocore reports acid-etching of enamel ○ RL Bowen introduces NPG-GMA as the 1st generation Advantages: dentin bonding agent Esthetic appearance 1970 Repairable, easy to maintain and refurbish ○ Acid-etching and enamel bonding Low cost compared to porcelain and gold alloys Reduce 1980 polymerization shrinkage ○ Dentin-bonded composites Bonding to dental tissue compared to gold ○ Fusayama introduces Total-Etch of dentin and enamel Minimal wear to occluding enamel compared to porcelain ○ Nakabayashi describes resin infiltration of dentin Early polishable outside or inside mouth collagen to form a “hybrid” layer Similar mechanical properties to dentin compared to 1990 ceramic ○ Kanka introduces dentin wet bonding techniques 1990 to 2000 Disadvantages: ○ 3 part, 2 part, 1 part Dentin bonding systems Inferior longevity compared to ceramics and amalgams 2000 to 2010 to current time Technique sensitive ○ Self-etching and self-adhesive bonding systems Color is changing during time developed Microleakage Secondary caries Basic Concepts of Adhesion More time and skill demanding 4 Mechanism of Adhesion Features of Tooth Preparation for Indirect Mechanical Adhesion Composite Restoration Interlocking of the adhesive w/ irregularities in the surface 1-5 to 2mm pulpal floor depth of the substrate, or adherend 1.5 to 2mm cusp reduction Isthmus width is atleast 1.5 to 2mm Adsorption Adhesion: Axial wall reduction is 1 to 2mm Chemical bonding between the adhesive The forces involved may be primary or secondary valence Cusp-Capping Partial Onlay forces Chemical bonding to the inorganic component (HA) or organic components (mainly type I collagen) of tooth Partial onlay is used when a cast metal structure restoration covers and restores atleast one but not Diffusion Adhesion: all of the cusp tips of a posterior tooth Interlocking between mobile molecules, such as the adhesion of 2 polymers through diffusion of polymer chain ends across an interface Precipitation of substances on the tooth surfaces to which resin monomers can bond mechanically or chemically Fundamental Concepts of Enamel and Dentin Adhesion Electrostatic Adhesion: Basic Concepts of Adhesion An electrical double layer at the interface of a metal w/ a Latin word adhaerere (to stick to) polymer that is part of the total bonding mechanism American Society for Testing and Materials - state in which Combination of the previous mechanism 2 surfaces are held together by interfacial forces which may consist of valence forces or interlocking forces or both TRENDS IN RESTORATIVE DENTISTRY Frequently viscous fluid that joins 2 substrate together by Classic Approach to Cavity Preparation solidifying and transferring a load from 1 surface to the Enamel bonding other Increasing demand for restorative and non restorative History esthetic treatments – Historical evolution of bonding agents is an ongoing process Fluoride which dates back to late 50s in a continuous efft=ort to improve the bonding of the restoration to the tooth and simplify the clinical steps MIDTERMS LESSON 1 TRINIDAD 2  LESSON 1: DIRECT COMPOSITE RESTORATIONS RESTO 2 1ST SEMESTER| 2024-2025 |DR. FILOTEO Adhesive Restorative Techniques Dentin Adhesion Restore Class I, II, III, IV, V, and VI carious lesion of traumatic Adhesion remains difficult defects Adhesive material can interact mechanically, chemically or both Change the shape and the color of anterior teeth (with full and Relies primarily on the penetration of adhesive monomers into partial resin veneers) the network of collagen (Type 1) fibrils left exposed by acid Improve the retention for porcelain-fused to metal or metallic etching crowns Bond all ceramic restorations GIC Seal pits and fissures PHOSPHATE-BASED SELF ETCH Bond orthodontic brackets ADHESIVE MATERIAL Bond splints for tooth luxations and Chemical bonding between periodontally involved anterior teeth and polycarboxylic or phosphate conservative tooth replacement prostheses monomers and hydroxyapatite Repair existing restorations Provide foundations for crowns Desensitize noncarious cervical lesions and Challenges in Dentin Bonding exposed root surfaces Mineralization (Dentin less mineralized compared to enamel) Impregnate enamel and dentin making Contain substantial proportion of water and organic material them less susceptible to caries (Type I Collagen) Bond fragments of anterior teeth Contain a dense network of tubules that connect the pulp w/ the Bong prefabricated fiber, metal and casts posts DEJ Reinforce fragile endodontically treated roots internally Bond strength are generally less in deep dentin than superficial Seal root canals during endodontic therapy dentin (1-step, self-etch adhesives) Seal surgically resected root apices Smear layer fills the orifices of dentin tubules, forming smear plugs and decreases permeability by nearly 90% Removal of smear layer allows diffusion of dentinal fluids. This can interfere with adhesion because hydrophobic resins do not adhere to hydrophilic substrates Additional Factors Enamel Adhesion Use of vasoconstrictors in LA, decrease pulpal pressure and fluid – The formation of resin microtags within the enamel surface flow in the tubules Inspired by the industrial use of 85% phosphoric acid to Radius and Length of the tubules facilitate adhesion of paints and Viscosity of the dentin fluid resins to metallic surfaces Pressure gradient Phosphoric acid gels Molecular size of the substances dissolved in the tubular fluid concentrations Rate of removal of substances by the blood vessels in the pulp ○ 30 to 40, with 37% being the most common ○ Etching time, 15 to 60 Development of Adhesive System seconds depends on the manufacturer’s instructions Acid Etching – Transforms the smooth enamel into an irregular surface and increases to surface free-energy 3 Morphologic Changes: Type I pattern: Involves the dissolution of prism caries without dissolution of prism Type II pattern: Peripheral enamel is dissolved, but the caries are left intact Type III pattern: Less distinct than the other 2 patterns When a fluid resin-based material is applied to the irregular etched surface, the resin penetrates into the surface, aided by capillary action Monomers in the material polymerize, and the material becomes interlocked with the enamel surface MIDTERMS LESSON 1 TRINIDAD 3  LESSON 1: DIRECT COMPOSITE RESTORATIONS RESTO 2 1ST SEMESTER| 2024-2025 |DR. FILOTEO Beginning (1950’s) Resin containing glycerophosphoric acid dimethacrylate (GPDM) could bond to a HCl acid etch dentin surface First Generation NPG-GMA by Cervident Low dentin bond strength In vivo results were discouraging when used to restore NCCL’s without mechanical retention Second Generation Clearfil Bond System (Japan) Phosphate-ester material (Phenyl-P and Hexydrohexyl methacrylate (HEMA)) Scotchbond (3M) Bondlite (Kerr) Prisma Universal Bond (Dentsply) Devoid of hydrophilic groups and had large contact angles on moist surfaces Third Generation INSERTION AND CURING The concept of phosphoric acid etching of dentin before application of a phosphate ester-type bonding agent was introduced by Fusayama et al. in 1979 Clearfil New Bond 1984 (HEMA and a 10 MDP Treatment of the smear layer w/ acidic primers was proposed using an aqueous solution of 2.5% maleic acid, 55% HEMa, and a trace of methacrylic acid (Scotchbond 2m 3M Dental Products) Scotchbond 2 wax the First dentin bonding system to receive “provisional” and “full acceptance” from the American Dental Association (ADA) Resin-Dentin Bonding Three-step: Etch-and-Rinse Adhesives Two-step: Etch-and-Rinse Adhesives FINISHING AND POLISHING Two-step: Self-etch adhesives Check the occlusion One-step: Self-etch adhesives Occlusal surface is shaped w/ a round or oval carbide bur Universal adhesives Polishing is accomplished w/ polishing cups MIDTERMS LESSON 1 TRINIDAD 4