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Questions and Answers
What is the primary purpose of acid etching on enamel?
What is the primary purpose of acid etching on enamel?
What concentration of phosphoric acid is preferred for etching enamel?
What concentration of phosphoric acid is preferred for etching enamel?
What is the recommended etching time for enamel?
What is the recommended etching time for enamel?
After etching, how should the enamel surface be rinsed?
After etching, how should the enamel surface be rinsed?
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What form of acid etchants is preferred and why?
What form of acid etchants is preferred and why?
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What is the bond strength range of composite resins to etched enamel?
What is the bond strength range of composite resins to etched enamel?
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Which component is least prevalent in dentin compared to enamel?
Which component is least prevalent in dentin compared to enamel?
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What is the primary organic component of dentin?
What is the primary organic component of dentin?
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What is the primary purpose of adhesion in restorative dentistry?
What is the primary purpose of adhesion in restorative dentistry?
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Which bonding mechanism involves the penetration of resin and the formation of resin tags?
Which bonding mechanism involves the penetration of resin and the formation of resin tags?
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What is meant by 'adherend' in the context of dental adhesion?
What is meant by 'adherend' in the context of dental adhesion?
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Which of the following is NOT a requirement for good adhesion?
Which of the following is NOT a requirement for good adhesion?
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What role does surface energy play in dental adhesion?
What role does surface energy play in dental adhesion?
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What does a low contact angle of an adhesive indicate?
What does a low contact angle of an adhesive indicate?
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Which component of tooth structure is primarily involved in the chemical bonding during the adhesive process?
Which component of tooth structure is primarily involved in the chemical bonding during the adhesive process?
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Why is the term 'one block concept' relevant to adhesive dentistry?
Why is the term 'one block concept' relevant to adhesive dentistry?
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Study Notes
Adhesion in Dentistry
- Adhesion is crucial for successful dental restorations.
- The development of bonding tooth-colored restorations eliminates the need for the "extension for prevention concept".
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Benefits of bonded restorations:
- Initial seal: minimizes microleakage, post-operative sensitivity & secondary caries.
- Strengthening: remaining tooth structure, promotes "one block concept".
- Conservation: preserves sound tooth structure.
- Retention and Resistance: minimizes need for additional mechanical retentive means.
Bonding Terminology
- Adhesion/Bonding: two surfaces held together by interfacial forces.
- Adhesive: bonding agent joining surfaces, resists separation, transmits loads.
- Adherend: surface or substrate adhered to.
- Adhesive Joint/Bonded Interface: the area where the adhesive and adherend meet.
Mechanisms of Bonding in Dentistry
- Micro-Mechanical: resin penetration and formation of resin tags within the tooth surface.
- Adsorption: chemical bonding to inorganic components (hydroxyapatite) or organic components (mainly type I collagen) of the tooth stucture.
- Combination of Mechanisms: both micro-mechanical and adsorption bonding.
Requirements of Good Adhesion
- Clean and Wettable Surface: The tooth substrate should be clean and have high surface energy to enable proper wetting by the adhesive.
- Low Surface Tension Adhesive: The adhesive should have low surface tension, characterized by a low contact angle and good spreading on the surface.
- Intimate Adaption: Close contact between the adhesive and the adherend.
- Proper Curing/Polymerization: Adequate curing is essential for strong bonds.
- Strong Bond Strength: The adhesive-adherend bond should resist debonding.
Enamel Bonding
- Acid etching transforms smooth enamel into an irregular surface (micro-pores), increasing surface free energy.
- Acid Etching Technique: Introduced by Buonocore in 1955 for sealing pits and fissures.
- Acid Concentration: 37% phosphoric acid is preferred.
- Etching Time: 15 seconds.
- Rinsing Time: Double the etching time, followed by proper drying resulting in a frosted, white surface.
- Optimum Etching: Results in mono-calcium phosphate monohydrate precipitate that can be easily rinsed off.
- Forms of Acid Etchants: Liquid or gel, with gel preferred for better control.
- Application Method: Gel etchants are applied with a syringe for ease and precision.
Bonding Agents
- Function: Flow into the microporosities of the etched enamel surface and form resin tags when polymerized by light activation.
- Bond Strength: 20-50 MPa, providing retention and preventing leakage around restorations.
Dentin Adhesion
- Hybrid Layer: adhesive monomers penetrate collagen fibers exposed by acid etching.
- Resin Tags: form within the dentinal tubules.
Challenges with Dentin Adhesion
- Chemical Composition: Dentin has a lower mineral content than enamel, making it more difficult to bond to.
- Dentin contains a significant proportion of water and organic material, compared to enamel's primarily mineral composition.
- Type I Collagen: is the principle organic component of dentin.
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Description
Test your knowledge on adhesion and bonding in dentistry with this quiz. Explore the benefits of bonded restorations, key terminologies, and mechanisms involved in dental adhesion. Understanding these concepts is essential for optimizing dental treatments and ensuring patient satisfaction.
