Dental Cements Pdf 1nv2c

DENTAL MATERIAL CEMENTS Dr Sara Sarraj

DENTAL CEMENTS are a classification of dental materials that are continually used in dentistry. The American Dental Association and the International Standards Organization (ISO) have teamed up to classify dental cements according to their properties and their

intended uses in dentistry.

Development of dental cements

1850s ZOE

1992 RMGI

Earl y 1900s ZP

1972

1900s

GI

Zinc carboxylate

CLASSIFICATION OF CEMENTS Type I: Luting agents that include permanent and temporary cements.  Type II: Restorative applications.  Type III: Liner or base applications 

LUTING CEMENTS 

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.

PERMANENT CEMENTS 

For the long-term cementation of cast restorations such as inlays, crowns, bridges, laminate veneers, and orthodontic fixed appliances.

TEMPORARY CEMENTS 

Temporary cements are used when the restoration will have to be removed. Most commonly, temporary cement is selected for the placement of provisional coverage.

TEMPORARY CEMENT Calcium hydroxide (Dycal)  Zinc oxide eugenol (IRM)  Nonzinc oxide eugenol (Cavit,Tempond)  Zinc polycarboxylate (Duralon)  Resins (Neo-Temp®) 

BASES & LINERS Materials used either to protect the pulp or aid pulpal recovery or both.  Pulpal irritants: 

Heat generated during drilling  Some ingredient of various materials  Heat produced by restorative materials  Forces transmitted to dentine through material  Galvanic Shock  Ingress of noxious products and bacteria through microleakage 

SELECTING BASE OR LINER Should be based on anatomical, physiological, and biological response characteristic of the pulp  Also based on the physical and chemical property of the material considered for use. 

PULP RESPONSE Is reversibly proportional to the thickness of remaining dentine.  Cutting odontoblasts extension that have not been exposed to any irritating episodes of caries or tooth wear would lead to death of these cells and their extensionsDead Tracts.(if remaining dentine is 1.5 mm and more.  If the cutting was atraumatic and coolant was used,replacement odontoblasts would not be formed hencefoth no reparative dentine would be produced.therefore base or liners are very important to seal those empty tubules. 

GENERAL RULE It’s desirable to have at least 2mm dimension of bulk between the pulp and metallic restoration, this bulk may include remaining dentine, liner ,or base.  Since composite is thermal insulator and ively inserted, a liner is indicated only if the excavation is judged to be within 0.5 mm of the pulp,Therefor (BW is important) 

BASES AND LINERS materials placed between dentin (sometimes pulp) and the restoration to provide pulpal protection .  1. Chemical protection  2. Electrical protection  3. Thermal protection  4. Mechanical protection  5. Pulpal medication  These functions differs as the depth of the restoration, and the type of restorative material

LINERS Are relatively thin layers of material(≤0.5mm) used primarily as barrier between the restoration and the remaining dentine following cavity preparation.  Liners should not extend to cavosurface unless sandwich technique is indicated. 

LINER FUNCTIONS Protective seal of exposed dentine  Electrical insulation  Thermal insolation ,which depends on remaining dentine.  Pulpal medicament :zinc oxide eugenol ,Ca(OH)2  Pulpal protection against 

Residual reactants diffusing out of restoration(Chemical)  Oral fluid Leakage(bacterial Influx) 

TYPES OF LINERS 

Thin film liners(1-50μm) Solution liners =5μm(Varnish)  Suspension Liners= 25μm,Ca (OH)2 suspension 

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Thick Film Liners (cement Liners)= (0.21)mm Pulpal medication  Thermal protection 

Liners

Thin Film

Solution 5μm

Thick Film

Suspension

Cement liner

25μm

0.2-1mm

SOLUTION 

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natural resin dissolved in non-aqueous volatile solvent, (ether, alcohol and acetone ),after application it evaporate leaving resin on the cavity walls These applied layer filled with pinholes, therefor multiple layers are indicated for an optimum function Do not dissolve in the oral cavity ,therefor can be used under: Amalgam, cast gold ,cohesive gold ceramic restoration Reduces discoloration by corrosion of amalgam , since it acts as dentinal seal. Should not be used under restoration that have organic solvent that reduces it’s value as cavity varnish (commercial BIS-GMA composite ) dry rapidly The solvent has anti microbial and antiviral action Thermal insulating effect

VARNISH  Several

fluoride-containing varnishes available (examples: Duraphat, Colgate Oral ). reduction in caries ranging from 18% to 77%.  When amalgam is first placed, the tooth/amalgam interface is not microscopically sealed. Eventually the varnish dissolves and is replaced with the corrosion products of the amalgam.

Cavity Varnish

CAVITY LINER SUSPENSION 

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These are suspension of calcium hydroxide , zinc oxide, and other material in resinous solution Used under tooth colored restoration Have greater physical integrity Have chemical neutralizing capacity for acids Dissolve in oral fluids causing severe microleakage, therefore they should be applied on dentine only, and do not extend to enamel. Dry slowly Provides thermal protection due to its increased thickness,with metallic restoartion

CALCIUM HYDROXIDE (CH)USES pulp-capping  a protective barrier between the dentin pulp complex and acid-containing cements and restorative materials, cements, and other base materials.  It will not inhibit the polymerization of acrylic and composite restorations  Improved physical properties with higher compressive strength and lower solubility. 

CA(OH) ADAVANTAGES Proven Clinical Efficacy. Shown to protect the pulp and promote the formation of Reparative dentin  Fast Setting  High Early Strength  Low Water Solubility  Available in Dentin or Ivory Shade. - allows for more natural looking esthetic restorations.  Excellent Handling  Easy to place, with ability to flow where needed while it stays in place when necessary 

CA(OH)2 SUPPLY Chemically cured forms Dycal, DENTSPLY Caulk)  light-cured forms :Prisma VLC Dycal, DENTSPLY CaulkChemically 

light-cured

Chemically cured

CLINICAL IMPLICATIONS Serves as an irritant stimulating the formation of reparative dentin; and  Second, the therapeutic affect of CH may be due to its ability to extract growth factors from the dentin matrix. The result is the formation of a dentin bridge, which allows pulpal repair. 

WHICH IS THE BEST LINER? The ability of calcium hydroxide to stimulate the formation of reparative dentine when it is in with pulpal tissue makes the material of choice for very deep excavation.  Liners and bases in very deep excavation should be applied without pressure.  Ca(OH) should be 1mm thickness near potential or actual exposure .  In these instances the base should be used in putty-like consistency ,so that less free acid ,and elimination of the rotary and pressure. 

CAVITY BASES Those cements commonly used in thicker dimensions beneath permanent restorations to provide for mechanical, chemical, thermal protection of the pulp.  Bases can be considered as restorative substitutes for the dentin that was removed by caries and/or the cavity preparation. 

CAVITY BASES Calcium Hydroxide Ca(OH)2  Zinc-Oxide Eugenol ZOE  Zinc Phosphate  Polycarboxylate  Zin-Silico-Phosphate  Glass Ionemer  Mineral trioxide aggregate (MTA) 

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Ca(OH)2+ZOE+MTA =Intermediary Bases

CALCIUM HYDROXIDE Has pH 11-13 therefore it can be used in deep cavity to neutralize the acids produced by bacteria,and as sub-base to neutralize the irritating acidic components of base or restoartive material  It’s supplied in two forms: 

Powder  Paste (Dycal) :chemically set, or light cured 

CA(OH)2 Advantages 

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Can be used virtually under all restorative materials, Pulpal compatibility, Promotes secondary dentin formation Antibacterial Light cured formulations have rapid setting and lower solubility in water Low cost Long history of use Easy manipulation

Disadvantages 

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Low strength, plastic deformation High solubility in water Short term seal against bacteria microleakage (therefore it’s indicating only for use as a pulp capping agent)

ZINC-OXIDE EUGENOL 

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Zinc-Oxide has pharmacological action on pulpal tissue,while Eugenol has topical anesthetic property(obtunding effect) As Intermediate restorative material provide an excellent seal of the cavity preparation ability of ZOE to reduce postoperative sensitivity Has long setting time:The clinician should allow approximately 24 hours to prior to placing amalgam above a ZOE base. Low compressive strength(brittle) Eugenol interfers with polymerization of resin material therefore can,t be used beneath,and substituted with Ca(OH)2.

REINFORCED ZOE chemical composition of ZOE is typically:  Zinc oxide, ~69.0%  White rosin, ~29.3%  Zinc acetate, ~1.0% (improves strength)  Zinc stearate, ~0.7% (acts as accelerator)  Liquid (Eugenol, ~85%, Olive oil ~15%) 

ZINC-PHOSPHATE CEMENT Powder:Zinc-Oxide  Liquid Phosphoric acid  Electrical and thermal insulator  Stay acidic after application ,therefore should be above Ca(OH)2 or ZOE in deep cavity  Has low linear of coefficient of thermal expansion  Compressive strength 100mpa  The material is acidic when placed (pH of approximately 3.5), but rises to a pH of 6.9 after a week. 

CLINICAL CONSIDERATION 

packages of ZP contain 20% more liquid than is necessary to combine with the powder. This is because some of the liquid will evaporate during use. This specification applies to zinc phosphate, zinc polycarboxylate, and GI together since they all are water-based. This is important for the clinician to consider. Since the water can evaporate, these materials can become viscous, leading to difficulty in seating crowns. Furthermore, loss of water will result in a decrease in the pH of the liquid, making the cement less biocompatible

ZINC POLYCARBOXYLATE CEMENT Powder :Zinc Oxide  Liquid:Polyacrylic acid  As electrical and thermal insualtor  Has low linear of coeffecient of thermal expansion  Has adhesive bond to dentine only 

ZPC(DURELON ) Zinc polycarboxylate adheres to the tooth via an interaction between the carboxylic acid and the calcium in the dentin  Polyacrylic acid has a very low pH (1.7), but the pH approaches neutrality upon mixing with the powder  the relatively large size of the polyacrylic acid molecule and/or its ability to combine with protein prevents it from diffusing into dentin tubules 

GLASS IONOMER Powder: ion leachable glasses  Liquid;Copolymer of polyacrylic acids  Has thermal and electrical insulation effect  Compressive strength 120MPa  Has adhesive bond to enamel and dentine 

RESIN MODIFIED GLASS IONOMER,RMGI(VITREBOND) first is their ability to ionically bond to tooth structure (between the carboxylate groups in the GI and the calcium ions in the enamel and dentin)  They release fluoride  Reduction in the consequences of micro leakage  antimicrobial properties  ability to adhere to and seal the dentin 

RMGI GIs should not be used as pulp-capping agents. In a clinical study, GI was found in the pulp chamber, which triggered a persistent inflammatory response and appeared to prevent the formation of dentin bridges.  They are extremely sensitive to moisture 

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when GI comes in with water, there is a decrease in its physical properties. In addition, resin-modified GIs expand after coming in with water.

PRECAUTION….. 

caution is needed because certain materials are not compatible with each other. For example, Yang and Chan demonstrated that varnishes can reduce the surface hardness of glass ionomers.

ZINC-SILICO PHOSPHATE CEMENT Powder: Acid soluble silicate +Zinc+magnisium  Liquid:Phosphoric acids  Translucent and superior to the opaque ZP cement  Has flouride release ,this has caries inhibition effect  Has the same clinical application of ZP  High stength and translucency =cementation of ceramic restoration, but has been replaced by GI and resin cements 

CLINICAL CONSIDERATION Selection Base or Liner depends on:  Thickness of remaining dentine  Adhesive property of both liner and base  Type of restoration placed above  When Dentine >2mm ,no need for pulpal protection ,and varnish is used against microleakage at the intersurface.  When remaining dentine is < 2mm ,Ca(OH), ZOE as liner or base .Eugenol acts as seadtive to the pulp. ZOE contraindicated under resin restoration since it counteracts polymeralization of resin

CLINICAL CONSIDERATION When remaining dentine is 0.5-1mm or near the pulp, use 1mm layer of Ca(OH)2 or MTA to encourage reparative dentine.  Adhesive cement liners are used after removal of extensive carious dentine, GI bonds to Enamel and dentine while polycarboxylate bonds to dentine only 

RESIN CEMENT Bond strength > Zinc phosphate 10 times   Retention  Reinforced ceramic - base Crown  Adhesive system (micromechanical bondtooth)  (chemical bond-porcelain,metal)  Low solubility   leakage 

CHARACTERISTIC OF TEMPORARY CEMENTS

Simple to use  Easy to remove to allow final placements of defenitive restorartion  Do not interfere with setting of defenitive material  Durable enough for few weeks  Biocompatible  Acceptably aesthetic 

ZINC-OXIDE EUGENOL Liquid

Eugenol,  H2O  acetic acid,  calcium chloride. 

Poweder

Zinc Oxide  Magnesium Oxide  Silica 

MODIFIED ZOE Addition of Zinc Acetate to powder  setting time to 5min  Addition of 10% hydrogenated resin to powder  strength (resin-bonded ZOE)  Addition of EBA (Ethoxy benzoic acid) 62% to liquid  strength 

VARIABLES AFFECTING THE CEMENT The thicker the mix the greater the srtength  Heat setting time therefore cooled slab is advisable  Dip the mixing instrument with powder to stop sticking of cement to instrument during placement  When luting, apply cement to restoartion before tooth. 

TYPES OF ZINC-OXIDE EUGENOL Type I 

Lacks strength and long-term durability and is used for temporary cementation of provisional coverage.

Type II 

Has reinforcing agents added and is used for the permanent cementation of cast restorations or appliances.

ZINC-OXIDE EUGENOL TypeIII 

Temporary filling and thermal insulation (base).

TypeIV 

Cavity liners

SUPPLY OF ZINC-OXIDE EUGENOL Liquid/Powder

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

Supplied as a two-paste system as temporary cement.  Pastes are dispensed in equal lengths on a paper pad and mixed. 

Liquid/Powder

Paste

FAST SETTING ZOE

MIXING ZOE 

3scops Powder+4 drops of liquids

VARIABLES AFFECTING CEMENTS Mixing time  Make sure to follow the manufacture’s directions for the mixing time, working time, and delivery time. 

LUTING CEMENTS REQUIREMENTS Long working time  Adhere well to both tooth structure and cast alloys  Non toxic to the pulp  Adequate strength properties  Be compressible into thin layer  Low viscosity  Low solubility  Good working setting characteristics  Excess could be easily removed 

ZINC PHOSPHATE Powder  zinc oxide  Magnesium oxide 

Liquid  phosphoric acid 

CLINICAL CONSIDEARTION ZP release irritants while setting, therefore dentine should be protected with varnish  Cements that are able to bond to dentine should have direct with dentine, therefore varnish should not be used under GI or polycarboxylate cement or composite or ceramic restoration. 

CAVIT suitable means of provisionally sealing prepared cavities  For sealing in medicinal inserts. They serve as dressings for the dentine surface, so protecting the periodontium and pulp against harmful influences.  In the case of root canal treatment, they also prevent infection of the peri-apical tissue caused by saliva. 

CAVIT 

Born 1947■Temporary filling of occlusion-loaded restorations

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Has three types Cavit W: its increased adhesion to the hard tooth substance and reduced final hardness, is specially designed for use in endodontic treatment.  Cavit G:is ideal for inlay preparations, since it is easily and cleanly removed without using rotary instruments.  Cavit LC (Light Cures): is a hybrid composite for temporary restoration of cavities. The newer version of all . 

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Release Fluoride Minimal Shrinkage when polymerizes provides high marginal integrity which prevents ingress of microorganisms into the cavity High mechanical strength Chemical stability in the oral environment Easy handling Easy removal Aesthetics Economy

CAVIT LC CAVIT LC is useful for sealing implant screwholes and as a lining for pre-formed temporary crowns and bridges.  Temporary sealing compound for temporary restoration of cavities. 

CAVIT G, COLTOSOL

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Temporary restoration of cavities for short time periods (1-2 weeks) Contraindicated incases of:   

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Allergy to components Long temporization requirements Temporary filling of cavities which include multiple areas and extend up to or under the gingiva (subgingival)

Advantages: Non eugenol formulation offers non irritating properties Easy to use packs and carves with no stringiness. self-curing (light cure preparations are available) under humidity  Simple to apply with filling instrument  Quick and void-free curing in a moist environment    

MINERAL TRIOXIDE AGGREGATE (MTA) root-end filling,  perforation repair,  vital pulp therapy,  apical barrier formation for teeth with necrotic pulps and open apexes.  Hydroxyapatite crystals form over MTA when it comes in with tissue fluid. This can act as a nidus for the formation of calcified structures after the use of this material in endodontic treatments 

MTA 

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The compressive strength of MTA increased with time in presence of moisture. Radiopacity is given by Bismuth Oxide. 

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MTA is less radiopaque than Super EBA, IRM, amalgam, and conventional gutta-percha, but in the same range as zinc oxide–eugenol-based root canal sealers.

better marginal adaptation to the root end cavity wall than other materials, and thus preventing microleakage. has antibacterial effects against Enterococcus faecalis and Streptococcus sanguis. Biocompatible

DIRECT PULP CAPPING The formation, quality, and thickness of a calcified bridge.  presence of inflammatory cells,  preservation of the pulp are considered evaluation criteria after vital pulp therapy 

CHEMICAL COMPOSITION OF MTA 1.Dicalcium silicate 2.Tricalcium silicate 3.Tricalcium aluminate 4.Gypsum 5.Tetracalcium aluminoferrite 6.Bismuth oxide 7.Manganese 8.Strontium 9.Chromophores (iron oxide) 10.Aluminium 11.Potassium

MTA DRAWBACKS long setting time  High cost  potential of discoloration 

RESIN CEMENTS They are very versatile (generally being of high compressive and tensile strength.  possess low solubility  different viscosities and different shades  When resins are used as a cavity liner, it is important to that it is the dentin bonding agent (examples: Clearfil SE Bond, Kuraray America; Excite, Ivoclar Vivadent) that comes into with the dentin 

CLINICAL CONSIDERATION Can,t be used for direct pulp cap(like GI)since they do not promote the formation of dentinal bridge,however they elicit a persistent mild inflammatory pulpal response  adhesives placed below amalgam restorations reduce microleakage,thus ing the current trend toward this practice of using resin as a liner.  Lining cavities with copal varnish is faster and less technique-sensitive than using adhesive resin, and resins cost more and have a limited shelf life. 

RESIN AS LINER 

It has been observed that some adhesives do not bond well to dentin in deep cavity preparations. This makes them more susceptible to polymerization shrinkage stress that develops in deep cavities.

TO OVERCOME SHRINKAGE ASSOCIATED WITH RESIN RESTOARTION IN DEEP CAVITY 

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Sadwish Technique:in which the lining materials(Vitrebond) are brought to the cavosurface margin under composite restoartion. Advantage:Release F and the released flouride can be externally replaced light-cured GI have been shown to provide a better seal

CONCLUSION 

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In of pulpal health, it is more beneficial to conserve tooth structure when possible than to remove that same tooth structure and replace it with a restorative material, Studies demonstrated that a 0.5-mm thickness of remaining dentin reduces toxicity of a material by 75%, and if that thickness is increased to 1.0 mm, a reduction of 91% is seen. An intact smear layer helps occlude the dentinal tubules and therefore provides a barrier to bacterial invasion,and liner is required to coat this fragile layer to reduce microleakage.

GOOD LUCK