23 Questions
Why do we need an intermediary restorative material?
To protect the pulp against various irritations
What is the best barrier between any restorative material and the pulp?
Dentin
What is the purpose of sealing dentinal tubules?
To prevent penetration through dentinal tubules
When is a base necessary according to the text?
When there is less than 2.0 mm thickness of dentin over the pulp
What are liners and bases used for in dentistry?
To protect the pulp beneath restorative materials
What do liners and bases aim to protect the pulp against?
Protecting it against thermal, galvanic, and chemical irritations
Which protective material is biologically compatible and non-irritating?
Glass Ionomer
What is the purpose of using a cavity sealer like varnish?
To seal dentinal tubules
Why can't varnish be used with bonded restorations of any type?
It interferes with the bonding of restorative materials
What is the ideal protective material that bonds to the tooth structure and is bondable to composite and amalgam?
Glass Ionomer
Which material provides adequate workability while being fast setting as a protective material?
Polycarboxylate
What is the main function of an intermediate liner material?
To provide a barrier to bacteria and oral fluids
Why is blocking out undercuts important for inlay or onlay preparations?
To reduce the bulk of the definitive restorative material
Which cement is contraindicated with resin restorations due to containing Eugenol?
IRM (Intermediary Restorative Material)
What property makes Glass Ionomer Cements unsuitable for direct pulp exposures or near exposures?
Low compressive strength
Why is a varnish required with Zinc Phosphate Cement?
To seal the dentinal tubules
What makes Polycarboxylate Cement different from Zinc Phosphate Cement?
It is less irritating to the pulp
Which cement has an acidic nature that can be irritating to the pulp?
Zinc Phosphate Cement
What is the additional benefit of B-Resin sealers compared to varnishes?
Bonding the restorative material to tooth structure
Which liner type is associated with an antibacterial effect and stimulation of reparative dentin?
Glass Ionomer Cements
What is the pH level of Calcium Hydroxide?
Alkaline
When is Calcium Hydroxide indicated for use?
In shallow preparations
Which base type is defined as a dentin replacement material?
MTA
Study Notes
Intermediary Base Materials
- Sound dentin is the best barrier between any restorative material and the pulp.
- Minimum dentin thickness of 2.0 mm over the pulp is recommended to prevent pulp reaction.
Need for Intermediary Restorative Materials
- To protect the pulp from thermal, galvanic, and chemical irritation.
- To seal dentinal tubules and prevent penetration through them.
- To block out undercuts for inlay or onlay preparations.
- To provide a flat floor to improve resistance form.
- To possess adequate strength to support the restoration.
Liners and Bases
- Intermediary materials placed beneath definitive restorative materials to protect the pulp.
- Functions: prevent penetration, protect pulp, block out undercuts, provide flat floor, and possess adequate strength.
Types of Liners and Bases
- Zinc phosphate (1870): high compressive strength, but irritating to the pulp.
- Zinc polycarboxylate (1963): non-irritating, but lower compressive strength.
- Glass Ionomer Cements (1972): close to ideal liner or base, releases fluoride, adhesive bond to dentin, and universal use.
- Reinforced Zinc oxide & Eugenol (IRM): sedative, palliative to the pulp, low compressive strength, and does not bond to tooth structure.
- B-Resin Sealers: serves the same functions as varnishes, but with additional bonding benefits.
Liners with Therapeutic Effect
- Glass Ionomer Cements: fluoride release, antibacterial effect, and stimulation of reparative dentin.
- Calcium Hydroxide: alkaline, neutralizes acidic effect, accelerates formation of reparative dentin, and chemically cured.
Indications and Contraindications of Calcium Hydroxide
- Indications: thin layer near the pulp, shallow preparations, and dentin thickness less than 0.5-1.0 mm.
- Contraindications: dentin thickness greater than 1.0 mm, and direct pulp capping.
Ideal Pulp Protective Material
- Biologically compatible, non-irritating, and anticariogenic.
- Stimulates dentin bridge formation, has sufficient strength, is acid insoluble, and has adequate workability.
- Bonds to composite, amalgam, and tooth structure, and is radiopaque.
Test your knowledge on the concepts of intermediary restorative materials, including why they are needed, sources of irritation, differences between sealers, liners, and bases, ideal indications and uses, and recent materials used. Explore the importance of sound dentin as a barrier between restorative materials and the pulp.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
