Dental Materials for Temporary Dressings, Cements, and Lining
- Temporary dressings:
- Zinc oxide eugenol is a common temporary dressing material that is bactericidal and easy to remove.
- Eugenol, derived from oil of cloves, has an obtundant effect on the tooth and decreases toothache.
- It is contraindicated if the final restorative material is composite.
- Kalzinol and Sedanol are examples of brands of zinc oxide eugenol.
- Temporary dressings are used to protect the pulp canal system during root canal therapy.
- Cements:
- Dental cements are used to bond indirect restorations like crowns to the natural tooth surface.
- Examples of dental cements include zinc oxide cement, zinc phosphate cement, and glass ionomer cement.
- Zinc oxide cement is self-setting and hardens when in contact with saliva.
- Zinc polycarboxylate cement adheres to enamel and dentin.
- Resin-based cement and copper-based cement are also used in dental restorations.
- Impression materials:
- Dental impressions are negative imprints of teeth and oral soft tissues used in various dental procedures.
- Impression materials vary in rigidity to obtain accurate impressions.
- Sodium alginate, polyether, and silicones are common dental impression materials.
- Plaster of Paris, zinc oxide eugenol, and agar were historically used as impression materials.
- Dental impressions are used in prosthodontics, orthodontics, restorative dentistry, dental implantology, and oral and maxillofacial surgery.
- Lining materials:
- Dental lining materials are placed between the remaining tooth structure and the restoration material.
- They protect the dentinal tubules and sensitive pulp, reducing post-operative hypersensitivity.
- Lining materials also act as an insulating layer, protecting the pulp from temperature changes.
- They prevent corrosion by galvanic cell when dissimilar metals are placed next to each other.
- Some examples of lining materials include calcium hydroxide, calcium silicate-based liners, and polycarboxylate cement.
- Types of lining materials:
- Calcium hydroxide is a lining material that stimulates the formation of secondary dentine.
- It has a low compressive strength and is often used in combination with other materials.
- Calcium silicate-based liners are preferred for their bioactive and sealing properties.
- Polycarboxylate cement forms a strong bond with dentin and enamel, releasing fluoride.
- Glass ionomer has the strongest compressive and tensile strength among lining materials.

Types of Dental Restorative Materials
- Amalgam: metallic filling material composed of a mixture of mercury and a powdered alloy
- Composite resin: mixture of nanoparticles or powdered glass and plastic resin
- Glass ionomer cement: restorative material with fluoride release and acid-base content
- Zinc oxide eugenol: lining material with low compressive and tensile strength
- Radiopaque materials: added to dental materials for visibility and detection

Physical Properties of Dental Restorative Materials
- Low thermal conductivity and expansion
- Resistance to forces and wear such as attrition and abrasion
- Resistance to chemical erosion
- Good bonding strength to the tooth
- Withstand everyday masticatory forces and conditions without fatigue

Biocompatibility and Aesthetics of Dental Restorative Materials
- Biocompatibility: coexistence with biological equilibrium of the tooth and body systems
- Common problems include chemical leakage, pulpal irritation, and allergic reactions
- Aesthetics: matching surrounding tooth structure in shade, translucency, and texture
- Tooth-colored fillings for cosmetic purposes
- Consideration of aesthetics in material selection

Application, Failure, and Evaluation of Dental Restorative Materials
- Application: direct restorations placed directly into a cavity on a tooth
- Factors affecting the longevity of fillings
- Failure of dental restorations: composites showing a higher failure rate than amalgam over five to seven years
- Evaluation and regulation of dental materials: conducted by organizations like the Nordic Institute of Dental Materials (NIOM) and regulatory bodies like the FDA
- Ongoing research and advancements in dental materials contribute to the improvement of dental treatments.