Untitled Quiz

Dental Cements

• Dental cements are supplementary materials used in restorative and esthetic procedures to maintain tooth health.
• Different types of cements are used based on the depth of the tooth preparation.
• Common types include liners, varnishes, desensitizers, bases, and bonding agents.

Pulpal Responses

• If decay reaches the dentin, patients may experience sensitivity and discomfort after restoration.
• The dentist might decide to add additional materials to address pulpal responses, providing medication and protection.

Tooth Cross-Section with Decay

• Displays tooth structure with decay, highlighting smooth surface cavity, pit and fissure cavity, and root cavity.

Bitewing X-Ray

• Shows various stages of dental caries (decay) in a bitewing X-ray.

Cavity Preparation (Prep)

• Cavity preparation involves removing decaying parts and shaping the tooth for restoring it.

Pulpal Responses - Stimuli

• Types of Stimuli: Physical, Mechanical, Chemical, Biological
• Examples of Stimuli: Thermal, Electrical, Handpiece, Occlusion, Acid from dental materials, Bacteria from saliva or caries

Dental (Cavity) Liners

• Liners are applied to the deepest part of the dental preparation.
• They seal the exposed surfaces and dentinal tubules of the tooth to prevent irritation
• Protect the pulpal tissues from physical, mechanical, chemical, and biological elements.
• Regenerate reparative or secondary dentin production.

Liners

• Thin-layered materials (less than 0.5 mm).
• Protect the pulp from chemical irritation.
• Not strong enough to resist condensation when placed in thick layers.
• Compatible with all restorative materials.

Calcium Hydroxide

• Available in light-cured and self-curing forms.
• Used as a pulp protector when pulp exposure is anticipated.
• Placed beneath any restorative material.
• Considered as a very soluble material.

Indications for Use - Liners

• Protect the pulp from chemical irritation.
• Stimulate production of reparative or secondary dentin.
• Are compatible with all types of restorative materials.

Liners - Advantages and Disadvantages

• Advantage: Biocompatibility and ability to stimulate reparative dentin.
• Disadvantages: Low compressive strength and very soluble.

Calcium Hydroxide (Dycal) - Preparation

• Usually comes in a two-paste system (base and catalyst).
• Equal amounts of base and catalyst are dispensed.
• Mixed in a circular motion until uniform in color.
• Mixing time: 10-15 seconds.
• Setting time: 2-3 minutes.

Liner - Application Process

• Placed only on the deepest dentin surfaces of the preparation.
• Not placed on enamel or in retentive grooves.

Cavity Varnish

• Used to seal dentinal tubules.
• Reduces microleakage around restorations.
• Protects the tooth from acidic cements like zinc phosphate (not to be used under composite resins or glass ionomer restorations).

Cavity Varnish - Application Process

• Applied after the liner and/or insulating base (except for zinc phosphate).
• Thin coating is applied to walls, floor, and margins of the cavity preparation.
• Usually a second coat is applied.

Desensitizer (aka Primer)

• Used to treat or prevent hypersensitivity.
• Alternative to varnish.
• Seals dentinal tubules to prevent oral fluids from entering and causing sensitivity.
• Can be used under all types of restorations.

Desensitizer (Primer) - Application Process

• May contain HEMA and glutaraldehyde (use sparingly).
• Avoid contact with soft tissues.
• Apply with a cotton-tipped applicator.
• Apply over all exposed dentin areas.

Dental Bases

• Provide pulpal protection during restorative procedures.
• Included in specific applications: protective, insulating, or sedative.

Dental Base Types

• Protective base: Protects pulp before restoration, reduces post-operative sensitivity, and minimizes pulp damage.
• Insulating base: Placed in deep preparations to safeguard the tooth from thermal shock.
• Sedative base: Used on pulps affected by decay or during mechanical decay removal to soothe them.

Dental Cements - Classification

• Luting Agents: Adhering material for restorations (temporary/permanent).
• Restorative Material (IRM): Intermediate restoration material.
• Liners & Bases: Materials to protect the pulp.

Dental Cements - Uses

• Permanent, intermediate, and temporary restorations.
• Luting agents for indirect restorations and orthodontic bands.
• Thermal insulators under metallic restorations (bases).
• Pulp capping agents and cavity liners.
• Root canal sealants.
• Periodontal packs.

Luting Agent

• Adhesive to hold castings to tooth structure.
• Intended for temporary or permanent cementation.

Luting Agent Consistency

• Permanent cements: Long-term cementation of cast restorations, similar to syrup consistency.
• Temporary cements: Used when removal is anticipated, similar to syrup consistency.
• Luting mix should string up then break approximately 1 inch from the slab.

Cementation

• Permanent cement: Long-term cementation of inlays, onlays, crowns, bridges, laminate veneers, and orthodontic appliances.
• Temporary cement: Used for provisional coverage.

Cement Removal

• Requires proper operator preparedness and knowledge of selected instruments (explorer, mouth mirror, scaler).
• Uses a fulcrum (finger rest).
• Floss used in embrasure areas.

Base/Temporary Restoration Consistency

• Should be thick and putty-like, with a slightly tacky texture that can be rolled into a ball, similar to playdough.

Variables Affecting Cementation

• Mixing time
• Humidity
• Powder-to-liquid ratio
• Temperature

Types of Cements

• Zinc-oxide eugenol (ZOE)
• Zinc phosphate
• Polycarboxylate
• Glass ionomer
• Composite resin

Zinc-oxide Eugenol (ZOE)

• Contains eugenol (soothing effect on the pulp).
• Neutral pH (less acidic than other cements).
• Strong smell, potentially irritating to oral mucosa (eugenol allergy possible).
• Not used under composite resins, glass ionomers, or other resin restorations (eugenol affects resin setting).
• ZOE Type I: Temporary cementation.
• ZOE Type II: Permanent cementation of cast restorations.
• ZOE Type III: Used for short-term restorations, or as a sedative dressing/insulating/sedative base.

Zinc-Oxide Eugenol (ZOE) - Mixing

• Liquid/Powder (e.g., IRM): Mixed on oil-resistant paper pad; mixing time 30-60 seconds, setting time 3-5 minutes in the mouth.
• Paste (e.g., TempBond): Two-paste system as a temporary cement; pastes are dispensed on an oil-resistant paper pad and mixed.

ZOE Type I (TempBond)

• Temporary cement.
• Zinc oxide eugenol base for provisional crown and bridge cementation.

ZOE Type III (IRM)

• Short-term restoration, primarily for primary teeth emergencies or caries management.

Intermediate Restorations

• Reduce sensitivity and discomfort in teeth.
• Preserve tooth function and esthetics until permanent restoration is placed.
• Protect preparation margins and prevent shifting of adjacent/ opposing teeth due to open spaces.
• Durable for up to 6 months.

Zinc Phosphate

• Zinc oxide and phosphoric acid.
• Phosphoric acid can irritate the pulp. A liner or desensitizer is needed beneath.
• Supplied in powder and liquid form.

Zinc Phosphate- Preparation

• Cement is slowly mixed over a large, cool, dry, thick glass slab to dissipate the heat.
• Ensure the slab is dry.
• The powder is added in small increments.
• Mixing is done until a 1-1.5 inch string forms when the spatula is lifted from the mix.
• Mixing time is 1.5-2 minutes.

Zinc Phosphate- Types

• Type I: (Fine grain) - Used in permanent cementation of casts.
• Type II: (Medium grain) - Recommended for insulating base in deep cavity preparations.

Polycarboxylate

• Not as strong as zinc phosphate but less irritating to pulp.
• Commonly found in powder and liquid form.
• Zinc oxide (powder) and polyacrylic acid (liquid).

Polycarboxylate - Use

• Permanent cement for cast restorations (stainless steel crowns & orthodontic bands).
• Nonirritating liner for composite or amalgam restorations.
• Intermediate restorative restoration

Polycarboxylate - Supplies

• Liquid can be measured using a squeeze bottle or calibrated syringe.
• Shelf life is limited due to liquid thickening through water evaporation.
• Mixed on a non-absorbent paper pad.

Other Cements

• Glass ionomer cement
• Composite resin

Dispensing Powders

• Condense powders before dispensing by tapping containers.
• For fluffed powders, gently invert the container several times.
• Immediately replace container caps after dispensing.
• Always dispense powders before liquids.

Dispensing Liquids

• Do not invert droppers.
• Avoid touching bottles to the slab before drop is dispensed.
• Immediately place bottle caps on bottles after dispensing.
• Dispense liquids after powders to prevent evaporation.

Summary of Base Materials

• Zinc Oxide Eugenol (ZOE): Insulating and sedative base.
• Zinc Phosphate: Excellent thermal insulation but can irritate pulp. Place over a liner.
• Polycarboxylate: Protective and insulating, nonirritating to pulp. Usable beneath direct and indirect restorations.
• Glass Ionomer: Fluoride release, good for deep preparations.