Dental Cements, Liners, Sealers (DMSE 2) PDF

DENTAL CEMENTS MDA 11th- Chapters 44-45 DENTAL LINERS AND BASES Liners and Bases Supplementary materials used in restorative and esthetic procedures for the health and well-being of a tooth. Depending on the depth of a tooth prep, the dentist will decide on using 1 or all of the following...

DENTAL CEMENTS MDA 11th- Chapters 44-45 DENTAL LINERS AND BASES Liners and Bases Supplementary materials used in restorative and esthetic procedures for the health and well-being of a tooth. Depending on the depth of a tooth prep, the dentist will decide on using 1 or all of the following 5 materials in an attempt to protect a tooth: ◼Liner ◼Varnish ◼Desensitizer ◼Base ◼Bonding agent  Pulpal Responses If decay has progressed through the enamel and into the dentin, patient may experience more sensitivity and discomfort after the restoration is placed. The dentist will decide if additional materials should be placed to provide medication and protection against pulpal responses Cross section of tooth with decay Bitewing with various stages of caries Cavity Preparation or “Prep” Process of decay removal and tooth design in preparation for restoring a tooth  Pulpal Responses Types of Stimulus Examples of Stimulus Physical Thermal, Electrical Mechanical Handpiece, Occlusion Chemical Acid from dental materials Biologic Bacteria from saliva or caries  Dental (Cavity) Liners Lines the deepest portion of the dental preparation Seals the exposed surfaces of the prepared tooth. sealsdentinal tubules Protects the pulpal tissue from irritation caused by physical, mechanical, chemical and biologic element. Regenerates production of reparative or secondary dentin Liners Are materials that are laid down in a thin layer (less than 0.5 mm) Protect the pulp tissue from irritation from chemical insult These are generally not strong materials and are not intended to be placed in thick amounts or to provide resistance to condensation. Liners are compatible with all types of restorative materials Liners Calcium Hydroxide Calcium Hydroxide Available in both light-cured and self- curing. Uses and characteristics: Pulp protector. Used when pulp exposure expected. Used under any restorative material. Very soluble  Dycal (calcium hydroxide) commonly used dental liner Indications for use: Protects the pulp from chemical irritation by its sealing ability. Stimulates the production of reparative or secondary dentin. Compatible with all types of restorative materials. Liners Advantage: biocompatibility and its ability to stimulate reparative dentin. Disadvantages: has a low compressive strength very soluble Preparation Calcium hydroxide usually comes in a two paste system (base & catalyst) mixed on a paper pad in equal parts (if not using the light cured version) ○ Dispense equal amounts of base and catalyst. ○ Mix quickly in a circular motion using a small spatula or ball applicator until uniform in color. ○ Mixing time is 10 - 15 seconds. ○ Setting time is 2-3 minutes.  Calcium Hydroxide (Dycal) Liner: Application process Placed only on the deepest dentin surface of the preparation Is NOT to be placed on the enamel or in a retentive groove Cavity Varnish Varnish Indications for use* Seal the dentinal tubules. Reduces microleakage around a restoration. Act as a barrier to protect the tooth from highly acidic cements such as zinc phosphate. * This material is contraindicated in its use under composite resins and glass ionomer restorations as it interferes with the bonding and setting reaction. Varnish: Application process Always applied after the liner and/or insulating base exception for zinc phosphate cement Thin coating of the varnish on the walls, floor, and margin of the cavity preparation. Apply a second coat.  A liner that seals the interface between the amalgam and the tooth structure can prevent the discoloration seen in the photo  Cavity varnish is applied with a cotton pellet and sterile cotton pellet forceps or applicator brush Location for placement of cavity varnish DESENSITIZER  Desensitizer aka Primer Indications for use Treat or prevent hypersensitivity. Used instead of a varnish. Seals the dentinal tubules to prevent oral fluids from seeping in between the tooth and restoration, which could eventually cause sensitivity. Ideal for use under all restorations Desensitizer: Application Process May contain hydroxyethyl methacrylate (HEMA) and glutaraldehyde, so use sparingly. Do not allow to contact soft tissues. Apply the dentin sealer with the cotton- tipped applicator. Apply over all areas of the exposed dentin. DENTAL BASES Dental Bases  Dental Bases Dental bases provide pulpal protection: Protective base: Protect the pulp before the restoration is placed. Reduces postoperative sensitivity and damage to the pulp. Insulating base: Placed in deep preparations to protect the tooth from thermal shock. Sedative base: Soothe a pulp that has been damaged by decay or irritated during the process of removing the decay (mechanical means.) DENTAL CEMENTS Classification of Dental Cements Luting Agents Restorative Material (IRM - Intermediate Restorative Material) Liners & Bases  Uses of Dental Cements As permanent, intermediate and temporary restorations As luting cements for indirect restorations and orthodontic bands As thermal insulators under metallic restorations (bases) As pulp capping agents and cavity liners As root canal sealants As perio packs Luting Agent A material that acts as an adhesive to hold together the casting to the tooth structure Luting agents are designed to be either permanent or temporary Luting Agent Consistency For cementation Permanent cements: used for long-term cementation of cast restorations Temporary cements: used when the dentist needs to remove the restoration at a later time The cement should be mixed so that it appears similar to syrup The mix should string up and break about 1” from the slab Cementation Permanent Cement long-term cementation used for inlays, onlays, crowns, bridges, laminate veneers, and orthodontic fixed appliances. Temporary Cement selected for the placement of provisional (temporary) coverage How a crown is made and inserted  Cement Removal Operator preparedness and knowledge Instruments selected for the procedure: ◼ Explorer, mouth mirror, scaler. Use of a fulcrum (finger rest) Use of dental floss in and around the embrasure areas. Base/Temporary Restoration Consistency Thick, putty-like Should be slightly tacky, but able to be rolled into a ball (kind of like 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 Dental Cements Zinc Oxide - Eugenol (ZOE)  Zinc-Oxide Eugenol (ZOE) Contains oil from cloves (eugenol), which has a soothing effect on the pulp Has a pH close to 7.0 (neutral), which makes it less acidic than most other cements Strong smell and can be irritating to oral mucosa (some patients may have allergy to eugenol) Cannot be used under composite resins, glass ionomers or other resin restorations - eugenol will affect the setting process of resin materials  Zinc-Oxide Eugenol (ZOE) ZOE Type I Lacks strength and long-term durability and is used for temporary cementation of provisional coverage. ◼e.g. Tempbond ZOE Type II Has reinforcing agents added and is used for the permanent cementation of cast restorations ZOE Type III Used for short-term restorations, sedative dressing or insulating/sedative base ◼e.g. Intermediate Restorative Material (IRM)  Zinc-Oxide Eugenol Liquid/Powder (e.g. IRM) Mixed on an oil-resistant paper pad. Mixing time ranges from 30 to 60 seconds. Setting time in the mouth ranges from 3 to 5 minutes. Paste (e.g. TempBond) Supplied as a two-paste system as temporary cement. Pastes are dispensed in equal lengths on an oil- resistant paper pad and mixed.  ZOE Type I TempBond: temporary cement with a zinc oxide eugenol base for provisional crown and bridge cementation.  ZOE Type III IRM: short- term restoration primary teeth emergencies caries management base  Intermediate Restorations Reduces sensitivity and discomfort to tooth Maintains function and esthetics to tooth until permanent restoration can be placed Protects margins of a prepared tooth Prevents shifting of adjacent/opposing teeth because of open spaces Can last for 6 months Dental Cements Zinc Phosphate  Zinc Phosphate Zinc oxide and phosphoric acid Phosphoric acid can be irritating to the pulp, so would be necessary to place a cavity liner or desensitizer under the zinc phosphate insulating base Is supplied in powder and liquid form Produces heat when mixed (exothermic)  Zinc Phosphate Type I (fine grain) Used for the permanent cementation of cast restorations such as crowns, inlays, onlays, and bridges. This material creates the very thin film layer that is necessary for accurate seating of castings. Type II (medium grain) Recommended for use as an insulating base for deep cavity preparations  Zinc Phosphate Preparation Cement must be spatulated slowly over a wide area of a cool, dry, thick glass slab to dissipate the heat. Make sure your slab is dry  me mindful of the dew point: the temperature where water or moisture is created Powder is divided into increments that vary in size. It is critical that the powder be added to the liquid in very small increments.  A few drops of the liquid (phosphoric acid) and a small mound of powder (zinc oxide) are placed on the glass slab. Zinc Phosphate Cement Preparation Mixing Start with smallest increment and graduate to largest Mix each segment approximately 15 seconds over a large area to dissipate heat Mix time is 1.5- 2 minutes  Mixing Zinc Phosphate A small increment of the powder is initially mixed into the liquid and spread out over the surface of the glass slab. Additional increments of powder are SLOWLY added  Powder is added until a 1 - 1.5 inch string of cement forms when the spatula is lifted from the mass of cement. The slow mixing over the entire surface of the cool glass slab results in greater working time for the clinician to manipulate the material before it begins to set.  Mixing Zinc Phosphate Precautions - Mix over a LARGE area to dissipate the generated heat as this heat will accelerate setting time. Dental Cements Polycarboxylate  Polycarboxylate Cements Not as strong as zinc Powder is mainly zinc phosphate, but less oxide irritating to pulp Liquid is a viscous Usually supplied as a solution of polyacrylic powder & liquid acid in water Properties viscosity, strength, bonding to enamel, and pH  Use of Polycarboxylate Permanent cement for cast restorations, stainless steel crowns, and orthodontic bands. A non-irritating liner under both composite or amalgam restorations. As an intermediate restoration.  Supply of Polycarboxylate Powder/liquid Liquid may be measured by using either the plastic squeeze bottle or the calibrated syringe-type liquid dispenser. Liquid has a limited shelf life because it thickens as its water evaporates. Mixed on a nonabsorbent paper pad.  Other Cements Glass Ionomer Cement Composite Resin TO BE DISCUSSED IN “RESTORATIVES”  Tips for Dispensing Powders Powders usually need to be condensed or fluffed before dispensing: Condense: tap container against counter to condense powder Fluffed: gently invert container several times Always replace caps immediately after dispensing powder, as humidity in the air will contaminate the powder. Dispense powders first, then liquids.  Tips for Dispensing Liquids Never invert dropper, as liquid will run back into rubber dropper, causing the rubber to deteriorate Never touch bottle to slab before the drop falls, this will result in a drop that is not a correct size Always dispense liquids after powders to prevent evaporation! Immediately place cap on bottle to prevent vaporization or contamination When mixing cements, the powder:liquid ratio depends on the intended use of the cement!  Summary of Cements that can be used as Base Materials Zinc Oxide Eugenol (ZOE)- insulating and sedative base Zinc Phosphate- excellent thermal insulation, but can be irritating to the pulp because of the phosphoric acid. Must be placed over a liner. Polycarboxylate- has protective and insulating qualities. Non-irritating to the pulp, can be placed under all types of direct and indirect restorations. Glass Ionomer- fluoride release, good for deep preparations