Zinc oxide-eugenol impression paste For full arch edentulous impression without or minor undercut. wash impression surgical paste Bite registration paste
P roperties @ Very low viscosity @ Low dimensional change 0.1% @ Irreversible chemical change Disinfection : 2% alkaline glutarldehyde solution
Manipulation Equal length of the two paste is extruded shorten by increase Temperature&Humidity Working time 3-5 min Mixing time 45-60 s Mixed with stainless steel spatula in paper pad or glass slab
Materials are classified as: HARD PASTE(TYPE 1) SOFT PASTE(TYPE 2) FINAL SETTING : Type 1: within 10 mins Type 2 : 15 mins
Manipulation
Advantage Accuracy of soft tissue impression (mucostatic) Inexpensive Adhere well to dental compound Good surface detail reproduction Good dimensional stability
Disadvantage May irritating to soft tissue Inadequate working or setting time -excessive humidity and/or temperature Distortion -unstable tray
ZINC OXIDE EUGENOL CEMENT ZOE cement introduced in 1858, is used as a Protective , sedative lining in deep carious cavities, For temporary filling Temporary cementing Pulp capping Root canal filling Periodontal / surgical packing Depending on their use they vary widely in their properties. In general, they are cements of low strength, are least irritating of all dental cements, are known to have an obtundant effect on exposed dentin.
CLASSIFICATION: (ADA SP. NO. 30) 4 TYPES TYPE 1 ZOE- for temporary cementation TYPE II ZOE – permanent cementation TYPE III ZOE – temporary filling, thermal insulation TYPE IV ZOE – cavity liners AVAILABLE AS : Powder, liquid Two paste system
COMMERCIAL NAMES Unmodified Tempac - type III Cavitic - type IV Tempbond - type I EBA alumina modified Opotow Alumina EBA - type II Polymer modifies Fynal - type II IRM - type III Non- eugenol Nogenol - type I Freegenol - type I
COMPOSITION POWDER Zinc oxide – 69.0% - principal ingredient White rosin - 29.3% - To reduce brittleness of set cement Zinc stearate -1.0% - Accelerator , plasticizer Zinc acetate – 0.7% - Is added in some powders, acts with eugenol in a similar manner as zinc oxide LIQUID Eugenol – 85.0 - Reacts with zinc oxide Olive oil - 15.0 - Plasticizer Zinc oxide is also main constituent of gutta-percha points mainly used in endodontic root canal filling, commonly known as GP Points.
Setting reaction First ZnO + water Zn ( OH ) 2 Second Zn ( OH ) 2 +2HE ZnE 2 + H 2 O SETTING TIME : 4 - 10 mins Water accelerates the reaction Zinc eugenolate is easily hydrolyzed by moistures
Factors affecting setting time Complete reaction between zinc oxide and eugenol takes about 12 hrs. this is too slow for clinical convenience. Manufacture : most active ZnO powders are those formed from zinc salts like zinc hydroxide, zinc carbonate by heating at 3000 degree Celsius. Particle size : smaller particles sets faster. Accelerators : Alcohol, glacial acetic acid, water Heat : cooling glass slab, slows reaction Retarders : the set can be treated with glycol , glycerin p/l ratio : higher the ratio, faster the set.
PROPERTIES MECHANICAL PROPERTIES: Compressive strength : are relatively weak cements. Ranges from a low of 3 -4 Mpa upto 50-55 MPa. Tensile strength : 0.32- 5.3 MPa Modulus of elasticity : 0.22 – 5.3 GPa THERMAL PROPERTIES: Thermal conductivity : 3.98[Cal. Sec-1 cm-2]x 10-4 Co-efficient of thermal expansion : 35x10-6/ celsius
Solubility and Disintegration : solubility is highest among cements (0.4 wt %) . Disintegrate in oral fluids. Solubility is reduced by increasing p/l ratio. Film thickness : is 25 um, is higher than other cements. Adhesion : do not adhere well to enamel or dentin Biological properties : PH and effect on pulp: PH is 7 -8 ; pulpal response classified as mild Bacteriostatic and obtundant properties Optical properties : set cement is opaque
Specification requirements Type Setting time [min] Compressive strength [MPa] Solubility [%] Film thickness [ µ m] Type I 4-10 35 maximum 2.5 25 Type II 4-10 35 maximum 1.5 25 Type III 4-10 35 maximum 1.5 -
MANIPULATION P/L SYSTEM : p/l ratio : 4:1- 6:1 by wt Oil of orange is used to clean eugenol cement from instruments. TWO PASTE SYSTEM : equal lts. Of each paste are dispersed and mixed until a uniform color is observed. SETTING TIME :4-10 MINS ZOE cements set quickly in mouth due to moisture and heat.
MANIPULATION Glass slab are recommended for EBA- alumina modified cements. after dispensing , powder is inco . Into liquid in bulk, kneaded for 30 secs, and then stropped for an additional 60 secs with broad strokes of spatula to obtain a creamy consistency. They have long working times. SETTING TIME: 9.5 MINS
Polymer reinforced zoe cement Composition: POWDER : Zinc oxide- 70 % finely divided natural or synthetic resins LIQUID : Eugenol acetic acid – accelerator Thymol - antimicrobial zinc oxide is surface treated SETTING REACTION: Similar to zoe cements. acidic resins, if present, may react with zinc oxide, strengthening the matrix. SETTING TIME : 6-10 MINS FACTORS AFFECTING SETTING TIME: Low p/l ratio inc. setting time Moisture: accelerates setting time.
PROPERTIES Cements have improved mechanical properties. Compressive st :48 MPa Tensile st : 4.1 Mpa Modulus of elasticity : 2.5 GPa Film thickness : 32 um solubility ,disintegration : 0.03 % wt pulp response : similar to unmodified zoe - moderate improved abrasion resistance and toughness. MANIPULATION : PROPER P/L is dispensed on a dry glass slab. Powder is mixed into liquid in small portions with vigorous spatulation. WORKING TIME : Long working time.
USES Luting agent As base As temporary filling material, As cavity liner
SPECIAL ZOE PRODUCTS Some zoe materials contain antibiotics such as tetracycline, steroids as anti- inflammatory agents. Their principal use is in pulp capping and RCT. One product also contains barium sulphate, which is radiopaque. ZINC OXIDE/ ZINC SULPHATE TEMPORARY RESTORATIONS: These are single component temporary filling materials. Supplied as a single component putty like paste in small tubes, syringes or plastic containers. Commercial Names : Cavit (ESPE) , Caviton (GC) , Coltosol (Coltene) Use in short term temporary restorations after caries excavation, RCT etc.
COMPOSITION: zinc oxide; zinc sulphate -1- hydrate ; calcium sulphate – hemihydrates ; dibutyl phthalate (plasticizer) ; diatomaceous earth. SETTING REACTION: sets by chemical reaction, it sets by reacting with water which it absorbs from the mouth or from the cavity. Setting occurs slowly, expands on setting. SETTING TIME : Surface hardens in about 20 to 30 mins. Complete hardening takes place in 2-3 hrs. PROPERTIES : May be white /pink colored. Has good initial sealing. as expands on setting, marginal seal is further improved. Seal gradually dec. with time. strenght is low, its life is short,so material must be used for not more than 1-2 wks. MANIPULATION : material is dispensed, inserted into cavity using a cement carrier . container should be closed immediately, material is condensed into cavity using a plastic filling instrument ; as sets by hydration , cavity should not be fully dried before placing the material.
ZINC OXIDE EUGENOL PASTE I t is probably the most commonly used root canal filling material for primary teeth. Camp in 1984 introduced endodontic pressure syringe to over come the problem of underfilling . Underfilling is frequently clinically acceptable. Overfilling may cause a mild foreign body reaction. Another disadvantage of ZOE paste is difference between its rate of resorption and that of the root tooth.
Properties ZOE Ca(OH) 2 with Iodoform (VITAPEX) KRI Paste Restore at the same rate as the tooth Harmless Overfill resorbs Antiseptic Easily applied Adheres to the wall Easily removed Radiopaque No discoloration Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Comparison of materials used for pulpectomy in primary teeth
CONCLUSION The material has been involved in a wide range of applications in dentistry, including use as an impression material for edentulous mouths, a surgical dressing, bite registration paste, temporary filling material, root canal filling material, cementing medium, temporary relining material for dentures . The physical and mechanical properties and handling characteristics generally are inferior to those of other long –term luting cements. Main advantage of improved ZOE cements is their biocompatibility.