Podcast
Questions and Answers
What is the primary composition of the smear layer formed on dentin?
What is the primary composition of the smear layer formed on dentin?
- Salivary glycoproteins, chips, and enamel
- Chips, hydroxyapatite crystals, collagen, saliva, and blood (correct)
- Hydroxyapatite crystals, glycoproteins, and enamel
- Enamel, collagen, and blood
Why might the smear layer be retained after dentin cutting?
Why might the smear layer be retained after dentin cutting?
- To prevent micromechanical bonding with resin
- To enhance bacterial penetration
- To lower dentin permeability and minimize post-operative hypersensitivity (correct)
- To increase dentin permeability significantly
What is the result of removing the smear layer from dentin?
What is the result of removing the smear layer from dentin?
- Reduction in micromechanical bonding with restorative resin
- Decrease in permeability of dentin
- Formation of a strong bond between dentin and restorative material (correct)
- Incorporation of microorganisms into the dentin
What is a characteristic of the smear layer formed on enamel?
What is a characteristic of the smear layer formed on enamel?
What role does 'conditioning' play in the selective acid demineralizing and etching process?
What role does 'conditioning' play in the selective acid demineralizing and etching process?
What does 'etching' typically involve in the context of adhesive dentistry?
What does 'etching' typically involve in the context of adhesive dentistry?
Which of the following is NOT a benefit of keeping the smear layer?
Which of the following is NOT a benefit of keeping the smear layer?
Which factor is associated with the increased permeability of dentin when the smear layer is removed?
Which factor is associated with the increased permeability of dentin when the smear layer is removed?
Which requirement is essential for successful wetting of an adhesive on tooth tissues?
Which requirement is essential for successful wetting of an adhesive on tooth tissues?
What should the surface tension of an adhesive be for sufficient wetting?
What should the surface tension of an adhesive be for sufficient wetting?
Which of the following is NOT a requirement for successful wetting of adhesive?
Which of the following is NOT a requirement for successful wetting of adhesive?
Which classification involves the use of primers and adhesives combined into one bottle?
Which classification involves the use of primers and adhesives combined into one bottle?
What characteristics should a successful adhesive joint possess?
What characteristics should a successful adhesive joint possess?
What type of adhesives are glass ionomer adhesives considered as?
What type of adhesives are glass ionomer adhesives considered as?
Which of the following is essential for a bonding process?
Which of the following is essential for a bonding process?
What is the process of increasing energy per unit area of a surface called?
What is the process of increasing energy per unit area of a surface called?
What is a characteristic difference between two-step and all-in-one self-etch adhesives?
What is a characteristic difference between two-step and all-in-one self-etch adhesives?
Which self-etch adhesive classification has a pH greater than 2.4?
Which self-etch adhesive classification has a pH greater than 2.4?
What makes bonding to dentin more difficult compared to bonding to enamel?
What makes bonding to dentin more difficult compared to bonding to enamel?
What contributes to the inherent intrinsic wetness of dentin?
What contributes to the inherent intrinsic wetness of dentin?
What is a challenge presented by the complex histological structure of dentin?
What is a challenge presented by the complex histological structure of dentin?
What is the pH range for mild self-etch adhesives?
What is the pH range for mild self-etch adhesives?
Why does deep dentin present more difficulty in bonding compared to superficial dentin?
Why does deep dentin present more difficulty in bonding compared to superficial dentin?
What is the estimated intrapulpal fluid pressure in dentin?
What is the estimated intrapulpal fluid pressure in dentin?
What type of adhesion involves electrostatic interactions?
What type of adhesion involves electrostatic interactions?
Which type of adhesion is primarily used in dental applications?
Which type of adhesion is primarily used in dental applications?
What type of adhesion occurs when there is bonding at the atomic or molecular level?
What type of adhesion occurs when there is bonding at the atomic or molecular level?
What is the term for the degree of spreading of one drop of liquid on a solid surface?
What is the term for the degree of spreading of one drop of liquid on a solid surface?
What is essential for an adhesive to produce good bonding?
What is essential for an adhesive to produce good bonding?
A contact angle of less than 90 degrees indicates what degree of adhesion?
A contact angle of less than 90 degrees indicates what degree of adhesion?
What describes the mechanical retention used in dental applications?
What describes the mechanical retention used in dental applications?
What happens at a contact angle of 0 or 180 degrees?
What happens at a contact angle of 0 or 180 degrees?
What is considered the Gold standard for adhesives?
What is considered the Gold standard for adhesives?
Which type of etch-and-rinse adhesive has low technique sensitivity?
Which type of etch-and-rinse adhesive has low technique sensitivity?
What is a disadvantage of etch-and-rinse adhesives related to the smear layer?
What is a disadvantage of etch-and-rinse adhesives related to the smear layer?
What is the main advantage of a particle-filled adhesive in etch-and-rinse systems?
What is the main advantage of a particle-filled adhesive in etch-and-rinse systems?
What happens if dentin is over-dried during the use of etch-and-rinse adhesives?
What happens if dentin is over-dried during the use of etch-and-rinse adhesives?
Which step is NOT required in self-etch adhesives?
Which step is NOT required in self-etch adhesives?
What is a primary disadvantage of multi-step etch-and-rinse adhesives?
What is a primary disadvantage of multi-step etch-and-rinse adhesives?
What is the risk associated with aggressive etching using phosphoric acid in etch-and-rinse adhesives?
What is the risk associated with aggressive etching using phosphoric acid in etch-and-rinse adhesives?
What primary nature does the hybrid layer possess?
What primary nature does the hybrid layer possess?
What happens to the dentin surface's bond strength if it is made too dry?
What happens to the dentin surface's bond strength if it is made too dry?
In the two-step etch & rinse adhesives, what components are combined into one solution?
In the two-step etch & rinse adhesives, what components are combined into one solution?
Which technique involves applying a water-based primer capable of re-expanding the collapsed collagen network?
Which technique involves applying a water-based primer capable of re-expanding the collapsed collagen network?
What is a characteristic of the hybrid layer related to its mechanical properties compared to dentin?
What is a characteristic of the hybrid layer related to its mechanical properties compared to dentin?
What scenario leads to a reduction in bond strength due to water droplets diluting the resin primer?
What scenario leads to a reduction in bond strength due to water droplets diluting the resin primer?
Why is a solvent-containing primer used in the wet bonding technique?
Why is a solvent-containing primer used in the wet bonding technique?
What does too much moisture on the dentin surface prevent?
What does too much moisture on the dentin surface prevent?
Which process is simplified by using self-etch adhesives?
Which process is simplified by using self-etch adhesives?
What occurs simultaneously with self-etch adhesives?
What occurs simultaneously with self-etch adhesives?
What is a disadvantage of one-step self-etch adhesives?
What is a disadvantage of one-step self-etch adhesives?
Why might mild self-etch adhesives require additional pre-etching on enamel?
Why might mild self-etch adhesives require additional pre-etching on enamel?
What is an advantage of polyacrylic acid conditioning?
What is an advantage of polyacrylic acid conditioning?
How long should polyacrylic acid be used to condition enamel and dentin?
How long should polyacrylic acid be used to condition enamel and dentin?
What is a characteristic of self-etch adhesives?
What is a characteristic of self-etch adhesives?
What is the main difference between mild and strong self-etch adhesives?
What is the main difference between mild and strong self-etch adhesives?
What do two-step self-etch adhesives consist of?
What do two-step self-etch adhesives consist of?
How do one-step self-etch adhesives differ from two-step self-etch adhesives?
How do one-step self-etch adhesives differ from two-step self-etch adhesives?
What enables mild self-etch adhesives to still achieve satisfactory bond strength despite shallow hybridization?
What enables mild self-etch adhesives to still achieve satisfactory bond strength despite shallow hybridization?
Which self-etch adhesive type creates the thickest hybrid layer?
Which self-etch adhesive type creates the thickest hybrid layer?
What is the primary difference between adhesion and cohesion?
What is the primary difference between adhesion and cohesion?
Which property is significant for reducing microleakage in dental restorations?
Which property is significant for reducing microleakage in dental restorations?
In an adhesive joint, what is the role of the adhesive?
In an adhesive joint, what is the role of the adhesive?
Which material has intrinsic self-adhesive capacity in dental applications?
Which material has intrinsic self-adhesive capacity in dental applications?
What is considered an adherent in the context of dental adhesion?
What is considered an adherent in the context of dental adhesion?
Which advantage is NOT associated with adhesion in dental restorations?
Which advantage is NOT associated with adhesion in dental restorations?
Which term refers to the forces between atoms or molecules at an interface that hold two phases together?
Which term refers to the forces between atoms or molecules at an interface that hold two phases together?
What is considered an adherend in resin composite bonding to tooth structure?
What is considered an adherend in resin composite bonding to tooth structure?
Study Notes
Dentin Bonding
Self-Etch Adhesives
- Do not use a separate etching step
- Two options:
- Two-step: acidic primer and adhesive are applied individually
- All-in-one adhesive: primer and adhesive agent are combined in one bottle
Classification of Self-Etch Adhesives
- Classified according to their aggressiveness or acidity:
- Ultramild (pH > 2.4)
- Mild (pH ≥ 2)
- Intermediate (pH = 1.5)
- Strong (pH ≤ 1)
Bonding to Enamel vs. Dentin
- Bonding to enamel is easier than bonding to dentin
Problems in Bonding to Dentin
- Heterogenous composition:
- High water and organic content (collagen)
- Only 70% inorganic hydroxyapatite
- Uneven distribution of constituents in intertubular and peritubular dentin
- Complex histological structure:
- Dentin composed of numerous dentinal tubules
- Each tubule surrounded by a collar of hypermineralized peritubular dentin
- Intertubular dentin less mineralized and contains more organic collagen
- Dentinal tubules diverge from the dentino-enamel junction to the pulp
- Inherent intrinsic wetness:
- Dentinal tubules filled with dentinal fluid
- Dentin under constant wetness
- Deep dentin has more intrinsic wetness than superficial dentin
- Dynamic tissue:
- Dentin subject to continuous physiologic and pathologic changes
- Presence of more than one type of dentin presents challenges in dentin bonding
- Presence of smear layer:
- A layer of cutting debris formed on the surface of dentin after cutting
Advantages of Etch-and-rinse Adhesives
- Proven effective bonding with enamel and dentin
- Three-step water/ethanol based adhesives are considered the Gold standard for adhesives
- Low technique sensitivity
- Possibility for particle-filled adhesive
Disadvantages of Etch-and-rinse Adhesives
- Time consuming due to multi-steps required
- Separate post-etching rinsing step is required
- Risk of over-etching dentin
- Total removal of smear layer can cause post-operative sensitivity
- Sensitive to over-wet or over-dry dentin condition
Properties of Hybrid Layer
- Primarily organic in nature
- Resistant to acids and proteolysis
- Lower modulus of elasticity than dentin
- Acts as an elastic buffering layer
- More tough and less hard than dentin
Wet versus Dry Bonding
- Conventionally, acid etched enamel was dried with short intermittent blasts of air
- However, this causes collapse of dentinal unsupported collagen network
- Two approaches to overcome this problem:
- Dry bonding technique:
- Air drying of enamel and dentin
- Applying a water-based primer
- Wet bonding technique:
- Leaving dentin moist
- Using a solvent-containing primer with water-chasing capacity
- Dry bonding technique:
If the Dentin Surface is Made Too Dry
- Collapse of the collagen fibers and demineralized dentin occurs
- Results in low bond strength
If the Dentin Surface is Too Wet
- Cannot check for the "frosted" etch appearance of the enamel
- Reduction in bond strength due to dilution of resin primer
The Smear Layer
- Formed on the surface of dentin after cutting
- Composed of chips, hydroxyapatite crystals, collagen, saliva, and blood
- Incorporates microorganisms
- Becomes packed inside the dentinal tubule forming a smear plug
To Remove or Keep the Smear Layer?
- Retain the smear layer because:
- Lowers dentin permeability
- Provides barrier to bacterial penetration
- Provides a drier surface for adhesion
- Minimizes post-operative hypersensitivity
- Prevents the ingress of irritants
- Remove the smear layer because:
- Incorporates microorganisms
- Loosely attached to the underlying dentin
- Exposed collagen enhances micromechanical bonding to resin
Steps of Bonding to Enamel & Dentin
- Etch & rinse adhesives:
- Selective acid demineralizing & etching
- Conditioning
- Etching
- Intimate molecular contact between adhesive and tooth tissues
Requirements for Successful Wetting of Adhesive
- Intimate molecular contact between adhesive and tooth tissues
- Cleanliness of the tooth tissues
- High surface energy of the tooth tissues
- Low-surface tension of the adhesive material
- Low viscosity of the adhesive
- Ability to displace air and moisture during the bonding process
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Description
Learn about self-etch adhesives in dentin bonding, their classification, and bonding to enamel vs. dentin. Understand the differences in acidity and application processes.
