Properties Of Resin-modified Glass-ionomer Restorative Materials And .
Dental ResearchProperties of resin-modified glass-ionomer restorative materialsand two polyacid-modifíed resin composite materialsThomas Attin*/Michael Vataschki*/Eltnar Hellwig**Abstract The objective of the study was to evaluate the physical properties of fourresin-modified glass-ionomer cements (Fuji ¡I LC, ¡onosit Fil, Vitremer,Photac-Fil) and nvo polyacid-modified resin composite materials (Dyract andVariglass VLC)). They were compared with a hybrid resin composite (blend-a-liix)and a chemically cured glass-ionomer cement (ChemFil Superior). The eompressive strength, flexura! strength, modulus of elasticity, and surface microhardness of the resin-modified giass-ionoiner materials and the poiyac id-modifiedresin-composite materials were inferior to those of the hybrid resin compositeand similar to those of the conventional glass-ionomer cement. The hybridresin composite exhibited the lowest resistance to wear caused by brushing. Some ofthe materials showed a marked decrease in hardness at depths exceeding 2.0 mm.Generally, the strength properties of the tested resin-modified glass-ionomermaterials and the polyacid-modified resin composite materials were inferior tothose of the hybrid resin composite. (Quintessence Int 1996:27:203-209.)Clinical relevanceTo achieve a sufficient depth of polymerization, thetested resin-modified glass-ionomer materials andthe polyacid-modified resin composite materialshould not he applied in increments exceeding 2 mm.In occlusal loaded areas, the use of the materialsshotild be restricted to small cavities without preparation of bevel-shaped cavosurface margins.IntroductionGlass-ionomer cements are becoming increasinglypopular in restorative dentistry. They are used especially in pédiatrie dentistry and for the restoration oferoded tooth areas,'' However, some shortcomings in* Assistant Professor, University Clinic of Dtntistry, Albert LudwigsUniversity, Freiburg, Germany.*" Professor and Chaiiman, University Clinie of Deniistiy, AlbertLudwigs University, Freiburg, Germany,Reprint requests: Dr Thomas Attin, Assistant Professor, UniversityClinic of Dentistry, Albert Ludwigs University, Hugstetter Strasse 55,D-79106, Germany,umber 3/1996physical properties and sensitive handling characteristics limit their routine use as a restorative material inpermanent teeth.-' A new generation of resin-modified(visible light-cured) glass-ionomer materials was introduced as liners and base materials to overcome theshortcomings of conventional glass-ionomer cements,''Recently, new types of resin-modified glassionomer materials and a polyacid-modified resincomposite material (PMRC) have been introduced.These new materials were developed as restorativematerials for Class I, Class III, or Class V cavities. Theresin-modified glass-ionomer cements have to bemixed before apphcation.The disadvantages of conventional glass-ionomercements include the brittleness and poor fracturetoughness of the materials,' Moreover, the hardenedsurface of glass-ionomer cement has low wear resistance against occlusal forces, Glass-ionomer cements,which are frequently used as a restorative material forClass V cavities, are additionally subject to abrasionfrom toothbrushing.Little is known about the fracture toughness,brittleness, and brushing abrasion of the newly developed resin-modified restorative materials. Compres203
Attin et alTable ¡Restorative materials tac-RIChemFil Superiorlonosit FilVi tremerVariGlass VLCDeTrey DentsplyBlendaxESPEDeTrey DentsplyDMG3M DentalDeTrey DentsplyPMRCL hybridRM GICGICRM GICRM GICPMRCFuji 11 LCGCRM GICBatch No.ColorMixingKL 15-72-293230002007X 031921214307067199304169202265 (powder)930617 (liquid)070523 (powder)281021 (liquid)A3U/A3A3LYA3A3UCapsule (no mixing)Capsule (no mixing)Predosed capsulePredosed capsulePredosed capsuleManualManualA3ManualPMRC - pol acid-inodified resin composite materialRM GIC resin-modified glass-ionomer cement;L hybrid - light-eured hybrid resin composite GIC - glass-Lonomer cement.sive strength, fiexural strength, and modulus of elasticity are physical parameters for fracture tougliness andbrittleness of a material. - Moreover, light-curingmaterials must be inserted in cavities in increments toprevent the occurrence of unpolymerized material indeeper layers.' Deeper layers may not be polymerizedeven if polymerization of the superficial layer iscomplete; deep unpoiymerized material may weakenthe restoration against occlusal loads. Therefore thedepth of cure of visible light-cured materials is ofinterest for the practical handling ofthe materials.The purpose ofthe present study was to evaluate thedepth of cure, surface microhardness, compressivestrength, fiexural strength, modulus of elasticity, andbrushing abrasion of four resin-modified glassionomer restorative materials and two PMRCs. Theproperties ofthe materials were compared to those of ahybrid resin composite and a conventional glassionomer cement.Method and materialsThe restorative materials tested in the study arepresented in Table 1. All materials were preparedaccording to the manufacturer's instructions. Thelight-cured materials were photocured (Optilux 400,Demetron Research) as described in the followingtestitig sections and removed from the molds. Thespecimens prepared for determination of compressive204strength and fiexural strength were additionally transferred to a light-curing oven (PLC Schütz Dental) toachieve complete polymerization of the specimens.This procedure was necessary because the size of thesespecimens did not allow homogeneous polymerizationwith the light-curing unit (Optilux 400). After theywere light-cured, the specimens were stored in distilledwater for 24 hours at 37 C. The chemically curedglass-ionomer cement specimens were varnished andstored in 100% humidity for 24 hours prior to beingtested.Hardness testingFive cylindrical specimens (2.0 mm in height and 10.0mm in diameter) of each material were fabricated in asteel mold. The light-cured materials were photocuredfor 60 seconds from both sides and removed from themolds. The top surfaces ofthe cylinders were groundfiat, polished (1,200 grit), and exposed to the lightcuring device again for 60 seconds. The specimenswere stored in distilled water for 24 hours at 37 C andsubsequently fixed on glass plates with a thermoplasticmaterial, aligned so that the pohshed surfaces ofthespecimens were parallel to the plates.Microhardness measurements were obtained with aVickers Hardness Tester (Type 3212, Zwick) at 100 gof force for 15 seconds. The use of Vickers hardnessmeasurements to determine microhardness of restora-Quintessence InternationalVolume 27, Number 3/1996
Atlin et altive materials is in accordance with recent studies.*''According to Willems et al. Vickers hardness measurements covered the requirements of the standard testmethod of materials as defined by the AmericanSociety for Testing and Materials.A pilot study had proved that measurement at 100 gof force for 15 seconds initiated no cracks on thesurface of the materials, thereby providing a size ofindentation that allowed measurement of the surfacehardness of all tested materials. The indentations weremeasured immediately after removal of the indenter.Five microhardness indentations were made on thepolished surface of each specimen. From these, anaverage Vickers Hardness Number (VHN) was determined.Compressive strength testingThe compressive strength of each material was measured in each of five cylindrical specimens. 6.0 mm inheight and 4.0 mm in diameter. The cylinders werephotocured for 60 seconds, transferred to the lightcuring oven, and subsequently stored in distilled waterfor 24 hours at 37 C,Compressive strength was determined in a universaltesting machine (UPM 81565. Frank) used at acrosshead speed of 0.7 mm/min. The forces requiredto produce fracture of the specimens were recorded.flextiral strength and modulus of elasticity testingRexural strength of the materials was measured bythree-point bending of rectangular beams, 2.0 x 2.0mm in cross section and 25.0 mm long. Five beams ofeach material were fabricated. The light-cured materials were photocured for 60 seconds from all sides,transferred to a light-curing oven and subsequentlystored in distilled water for 24 hours at 37 C.Afterward the specimens were placed in a special jigwith a distance of 20.0 mm between the lower supporting points. The jig was mounted in a universaltesting machine and the beam was centrally loadedwith a crosshead speed of 1.0 mm/min. The forcemeasured at fracture of the specimen and the deformation of the beam at fracture were recorded. Flexuralstrength {a ) and modulus of elasticity ( ) werecalculated with the following formulas:3xfx/2 Xf X P4 X Vf X h ' X'-rnnP p* '-natif-in-ilWnliTnnW .Nnmhpr 3/1996where F - force required to produce fracture; / distance between the supporting points; ii' width ofthe beam; /? height of Ihe beam; and d deformationof the beam at fracture.Abrasion resistance testingSix cylinders (2.2 mm in height and 10.0 mm indiameter) of each material were prepared and photocured from both sides for 60 seconds. Following waterstorage for 6 weeks at 37 C, the cylinders werepohshed (600 grit) until they were reduced 0.2 mm inheight. Tlie height and the diameter of the specimenswere controlled with a micrometer to an accuracy of5.0 \im and recorded. For determination of density ofthe materials, the specimens were weighed ( 1574 MP8,Sariorius), and the densities were calculated as amathematical function of volume and weight. Thedensities of the six specimens were averaged for eachmaterial.The specimens were mounted in a toothbrushingmachine by means of impression material (Extrudemedium consistency, Kerr/Sybron). A pilot study hadproved thai no remnants of impression material couldbe detected on the surface of the specimens under alight microscope (x 40 magnification). The toothbrushing machine consisted of a motor, which imparted a reciprocating motion of one toothbrush head(blend-a-med medical, Blendax). The specimens werealigned so that the brushing head moved parallel to ihesurface of the specimens. For each specimen, a newbrushing head was used. A frequency of 40,000brushing strokes (120 strokes/min) was carried out ata load of 2.2 N in an abrasive slurry (33.4% dicaiciumphosphate in distilled water, glycerine, and formalin).After they were brushed, the specimens were weighedagain. Substance loss (in microns) of the specimenswas calculated as a mathematical flinciion of volumetric loss and density.Depth of cure testingThree specimens each of the iight-curcd materials wereprepared for determining initial depth of cure. Thematerials were inserted in cylindrical steel molds(6.0 mm in height and 4.0 mm in diameter). Glassplates were placed forcefully on top of the molds tocreate a planar surface. The restorative materials werepolymerized by application of the visible light source,at a distance of 1.0 cm, perpendicular to the top of thecylinder. The light was activated for 40 seconds. Afterthe light activation was completed, the specimens were205
Attin et alTable 2 Mean (SD) surface microhardness(Vickers hardness number)MaterialMicrohardnessblend-a-luxChemFil SuperiorDyracIIonosit FilVitremerVariGlass VLCPhotac-FilFuji II LC97.8 (2.9)59.8 (2.1)54.9 (0.6)41.7(1.7)41,4(3.0)38.3(1.7)37.4(1.7)36.2 (0.9)Values connected by a vertical line are not signiticaijtly different (level ofsignificance» i ' , 0 5 ) .Table 3Mean (SD) compressive strength (N/mm )MaterialCompressive strengthblend-a-luxDyractVitremerVariGlass VLCIonosit FilChemFii SuperiorFuji II LCPhotac-Fil381.3 (29.1)255.6(18,8)176.1 { 8,4)167.0 ( 8.3)161.8(11,7)161.1 (12.5)159.7 ( 7.6)128.2(15.3)Vatues connected by a vertical line aie not significanlly difièrent (level afsignificance - P . 0 5 ) .Table 4 Mean (SD) flexural strength and tnodulusof elasticity (N/mm )Materialblend-a-luxDyractVitremerFuji II LCIonosit FilVariGlass VLCPhotac-FüChemFil SuperiorFlexural strength Modulus of elasticity130,6(3,8)123.9(2,4)55,9(2.5)54,6 (2,7)3S.8 5)7596(792)6249 (526)6751 (581)4749(315)4326 (938)11850(448)1Values connected by a /enicai line are not significantly different (level ofsignificance 206taken out of the molds, and the soft, uncured matertaiat the bottom of the cylinders was removed with aplastic sealer. The cylinders were bisected along theirlength whh a diamond saw, and the sectioned surfaceswere polished (1,200 grit).The two halves were fixed on glass plates asdescribed for hardness testing, and, 10 minutes afterpolymerization, the Vickers hardness was measuredperpendicular to the long axis of illumination at bothhalves. The microhardness ( 100-g load for 15 seconds)was determined at steps of 0,5 mm each from thesurface of the cylinders that had been photocured. Thesites were located exactly in the middle axis of thesectioned surfaces.Statistical analysisStatistical analysis of the mean values among thematerials was achieved by analysis of variance andScheífé's test. Differences between hardness at 0,5and 2,0-mm depths for each material were subjected toan unpaired t test followed by Bonferroni Correction,The level of significance was set at P .05 in all tests.ResultsMicrahardnessTable 2 presents the mean values obtained from thedetermination of surface microhardness. All glassionomer materials had statisticaUy significantlylower microhardness than did the hybrid resin composite. The conventional glass-ionomer cement andthe PMRC, Dyract, demonstrated statistically highersurface hardness than did the remaining glass-ionomercements,Compressive strengthThe average compressive strengths of the materials areshown in Table 3. The hybrid resin composite yieldedthe highest compressive strength. No statisticallysignificant difference was observed between the hybridresin composhe and Dyract. Except for Fuji II LC andPhotac-Fil, all resin-modified glass-ionomer materialsexhibited higher compressive strengths than did theconventional glass-ionomer material and lower strengthsthan did the hybrid resin composite,Flexural strength and modulus of elasticityTable 4 presents the average flexural strengths andmodulus of elasticity of the tested materials. The hybridQuintessence InternationaiVoiume 27. Number 3/1996
resin composite revealed the highest flexural strength,and the conventional glass-ionomer cement showedIhe lowest strength. The moduli of elasticity of thehybrid resin composite and of the chemically curedglass-ionomer cement were higher than those of theresin-modified glass-ionomer materials and thePMRCs.Abrasion resistanceThe average abrasion caused by brushing of thematerials is shown in Table 5. The hybrid resincomposite and one PMRC exhibited statisticallysignificantly higher abrasion than did the glassionomer matcriais. Except for Photac-Fil. all rcsinmodified glass-ionomer materials showed higher abrasion resistance than did the conventional cement. Thedifferences between the conventional cement and theresin-modified glass-ionomer materials were not statistically significant.Depth of cureTo simplify the illustration, the means of the microhardness values at various depths of the materials arepresented in two separate figures (Figs la and Ib).Uncured material at the bottom of the cylindricalspecimens did not allow for determining microhardness of Ionosit Fil, VariGlass VLC, and Photac-Fil atdepths exceeding 3.0, 3.0, and 4.0 mm, respectively.VariGlass VLC, Dyract, Ionosit Fil, and blend-a-luxexhibited a continuous decrease in microhardnessfrom 0,5 mm depth to the bottom of the cylinders. Themicrohardness profiles of Fuji II LC and Vitremerstayed nearly constant. Photac-Fil showed a loss inmicrohardness at a depth exceeding 3.5 mm.In Table 6, the difference in hardness between 0.5and 2.0 mm in depth is expressed in relation to thehardness at 0.5 mm in depth. The relative decrease inhardness from 0,5 to 2.0 mm in depth was highest forDyract and the hybrid resin composite (blend-a-lux).Dyract and Photac-Fil revealed statistically significantdifferences in hardness between 0,5 and 2.0 mm indepth. The resin-modiñed glass-ionomer materials,Ionosit Fil, Vitremer, and Fuji II LC, showed merely aslight loss in hardness at 2,0 mm in depth.DiscussionThe results of the study demonstrated marked differences in physical properties among the tested mate,.Number 3/1996Table 5 Mean (SD) abrasion of the tested materialscaused by brushingMaterialblend-a-luxDyractPhotac-FilChemFil SuperiorIonosit FilFuji II LCVi tremerVariGlass VLCAbrasion65.2 {3,7)53.6 (9.8)35,0(3,3)34.4(3.6)30.4(1.5)30.2(2.3)28.8 (2.6)21.4(1.2)Values connected by a vertical line are not significantly different (level a(significance »rials. The rankings of the glass-ionomer restorativematerials varied among the different tests, Fxcept forthe depth of cure, all glass-ionomer materials exhibitedphysical properiies that were different from those ofthe hybrid resin composite, Dyract revealed propertiessimilar to those of the hybrid resin composite in alltests. Similar results had been described in previousinvestigations, which have described its properties asresembling those of a resin composite rather thanthose of a glass-ionomer material.'"'' The average surface microhardnesses of the glassionomer restorative materials and the PMRCs werelower than those of the control materials. The wearresulting from abrasion, unexpectedly, did not correlate with the Vickers hardness value of the materials.It was expected that the coefficient of wear woulddecrease as the hardness of the material increased. ' This was not true for the present results. In the presentstudy, the hybrid resin composite yielded the lowestwear resistance and the highest surface hardness.This finding can partly be explained with anobservarion made by Lugassy and Greener.''' Theyshowed that the abrasion of an unfilled resin is lowerthan that of a filled resin and that the pattern of weardiffers. It is assumed that glass-ionomer cements reactlike unfilled materials. With unfilled materials, the wearis more uniform than is wear exhibited by conventionalresin-based, filled resin composites, in which fiUer"pluck-out" predoniinates.'* A slurry containing 33.4%dicalcium phosphate with low abrasivity was used,'*207
Attin et al100Figs la and Ib Mean Vickers microhardtiess values (VHN) at variousdepths.[VHN]b1end-a-lux «Dyract âlonositFJI80604020Fig la40[VHN]302010-»Fuji II LC -*-Vitretner - Photac-Fil23Depth [tnm]Fig IbTable 6 Average loss of microhardness from 0,5 to2,0 mm in depth {%)MaterialDyract*blend-a-luxPhotac-Fil*"VariGlass VLClonosit FilVitremerFuji II LCLoss of hardness31.6(3.2)22.6 (7.0)13.4(1.4)12.2(5.4)6.8 (2.9)4.5 (1.6)- 0.6(2.6)* Statistically significant loss of hardness from 0,5 to 2,0 ram in depth.Values connected by a vertical line are not significantly different (level ofsiEnifieance - /' ,05¡,208The detached particles of the hybrid resin compositeact as an additional abrasive agent themselves andenlarge the abrasion property of the slurry.The finding observed in this study may be extrapolated to the in vivo situation, because it correspondswith the findings of Krejci et al.' They also found thatthe in vivo wear of a hybrid resin composite is higherthan the wear of the PMRC Dyract. However, clinicalinvestigations are necessary to determine the longterm wear performance of these new materials,Mexural strengths of the glass-ionomer materialsand the PMRC:s were lower than that of the hybridresin composite. Except for the conventional glassionomer cement, the flexural strength of all materialsQuintessence InternationalVolume 27, Nutnber 3/1996
Attin et alcorrelated with their modulus of elasticity; ie, thehigher the recorded fiexural strength, the higher themodulus of elasticity. The conventional glass-ionomercement revealed a high modulus of elasticity and alow fiexural strength. This finding underlines thesusceptibility to brittle fracture of conventional glassionomer cements. Except for one PMRC. the resinmodified glass-ionomer materials showed significantlylower fiexural strengths than did the hybrid resincomposite. It is conceivable that the low fiexuralstrengths of these materials exerted an infiuence on thefracture toughness of these materials.The compressive strengths of the resin-modifiedglass-ionomer materiais were significantly lower thanthat of the hybrid resin composite but comparable tothe compressive strength ofthe conventional cement.The compressive strength of Dyract was not significantly different from that ofthe hybrid resin composite. The compressive strength of a restoration contributes to its fracture resistance against loading.** Thereduced compressive strengths and the concomitantlow fiexural strength of the resin-modified giassionomer restorative materials may limit the use of thesematerials to smali cavities with little occlusal stress.Depth of cure was determined in a way similar tothat described by Baharav et al." Most ofthe testedmaterials exhibhed a decrease in hardness from thesurface to the depth ofthe specimens. For statisticalanalysis, the loss of hardness between 0.5 and 2.0 tnmin depth was calculated in relation to the hardness in0.5 mm in depth. The hardness at 2.0 mm in depth wasselected as a reference because the manufacturersrecommend use of layers of approximately 2.0 mmwhen the materials are applied in an incrementaltechnique. In this study, the initial depth of cure wasdetermined 10 minutes after polymerization ofthelight-cured materiais. Resin-modified glass-ionomermaterials undergo ¡iirther chemical reactions afterphotocuring, thereby increasing depth of cure.'** However, the present results indicated that, for most ofthetested materials, the thickness of increments in a cavityshould not exceed 2.0 mm to achieve maximal initialhardness ofthe restoration.higher resistance to wear caused by brushing than did ahybrid resin composite. To achieve higher initialhardness, the thickness of increments of the testedmaterials in a cavity should not exceed 2.0 mm.References1. Muuni CJ. Restorations of eroded199û-,l2Û:31-33.J Am Dent Assoc2. Lcinfelder KP. Glass ionomers; Currenl clinical developments. JAmDentAssoc 1993:124:62-64.3. Croll TP. Glass ionomers for infants, children, and adolescents. JAm Dent Assoc 1990:120:65-68.4. Maihis RS. Ferracane JL. Properties of a glass ¡o nomer/resincomposite hybrid material. Dent Mater 1989iS:355-358,5. McKinney JE. Antonucci JM. Rjpp NW. Wear and microhardnessof glass-ionomer cemenls. J Dem Res I987;66:1134-1139.6. Tam LE. Pulver E, McComb D, Smith DC. Physical properties ofcalcium hydroxide and glass-ionomer base and lining materials.DenI Mater 19S9:5 145-1497. Fusayama T. Indications for self-ejred and light-cured adhesivecomposite resins. J Prosthet Dent 1992:67:46-51.8. Forss H. Seppa L, Lappalainen R. In vitro abrasion resistance andhardness of glass ionomer cements. Dent Mater l990;7:3É-39.9. Willems G, Lambrechts P. Braem M. Celis JP. Vanheric G. Aclassification of dental composiles according to their morphoiogicaland mechanical characteristics. Dent Maler Í992:8:31O-319.10. Attin T. Buchalla W. Kielbassa AM. Hellwig E. Curing shrinkageand volumetric changes of resin-modified glass lonumer restorativemateriais. Dent Mater 1995:11:360-36311. Käse R. Zusammenstellung der yerfügharen Daten zu Dyract.Constance. Germany DeTrey Dentsply, 1993.12. Krejci I. Gebauer L. Häusler T, Lutz F. Kompo mere—Amalgamersatz für Milchzahnltavitâten? Schweiz Monatsbthr Zahnmed1994:104:724-730.13. Horta M. Hinikawa H. Abrasion resistance of restorative glassionomer cements wiüi a hght-cured surface coating. Oper Dent1994; 19:42-46.14. Lugassy AA, Greener EH. An abrasion resistance study of somedental resins. J Dent Res 1972;5h967-972.15. Abell AK. Leinfdder KF. Turner DT. Mieroscopic obsen-atiuns ofthe wear of a tooth restorative composite in vivo. J Biomed MaterRes 1983:17:501-507.16. HefTereii JJ. Kingman A. Stookey GK. Lehnlioff R. Müller T. Aninlcrnational collaborative study of laboratory methods for assessingabrasivity to dentin. J Dent Res 1984:63:1176-1179.Summary17. Baharav H. Abraham D, Cardash S, Helfl M. Effect of exposure timeon the depth of polymenzation of a visible light-cured eompositeresin. J Oral Rehabil 1988:15:167-172.The tested resin-tnodified glass-ionomer materials andthe PMRCs showed inferior strength properties but18. Burke FM, Hamlm PD, Lynch EJ. Depth of cure of light-cured glassionomer cements. Quintessence lnt 1990;21;977-981.D209
PMRC - pol acid-inodified resin composite material RM GIC resin-modified glass-ionomer cement; L hybrid - light-eured hybrid resin composite GIC - glass-Lonomer cement. sive strength, fiexural strength, and modulus of elasti-city are physical parameters for fracture tougliness and brittleness of a material. - Moreover, light-curing
3/16" hs glass 3/16" hs glass 0.090" sentryglas.65" min. typ. glass bite glass type "b" 3 6 7 5 3/16" hs glass 3/16" hs glass 0.075" saflex storm glass.65" min. typ. glass bite exterior glass type "a" 2 3 6 7 5 2 dowcorning 899 structural silicon note: glass capacities are based on astm e1300-12 (3 sec. gusts) by dupont interlayer by old castle .
_ 3535 RelyX Luting Plus Automix Resin Modified Glass Ionomer Cement Syringe Value Pack 273.93 _ _ 3535TK RelyX Luting Plus Automix Resin Modified Glass Ionomer Cement Syringe Trial Kit 104.60 _ _ 3525TK RelyX Luting Plus Resin Modif
What's Smart Glass? Switchable glass is called smart glass,privacy glass is a new building decoration material that combines the smart film with glass. This laminated smart glass is an innovative opto-electrical laminated glass that composed of two layers of toughened glass on the outer side ,PDLC film in the
Preventive Dentistry The preventive resin (composite resin/sealant) restoration: Nine-year resnlts Milton Houpt* / Anna Fuks** / Eliezer Eidelman*** Thi.i study vfflj performed to examine the 9-year .success of the composite resin/seaUmt res-toration, which uses "sealing for prevention
Pipe, valves and fittings shall be made from HP resin produced by one supplier. The resin shall meet or exceed the requirements outlined for a Type II suspension grade homopolymer resin in ASTM D-3222. Resin is approved for contact with foodstuff as per the FDA CFR, Title 21 (2001) 177.1520. Pipe shall be made of Solef 1010/0001 HP resin.
D2332 Resin-based composite - three surfaces, anterior 13 D2335 Resin-based composite - four or more surfaces or involving incisal angle, anterior. 15 D2390 Resin-based composite crown, anterior. 30 D2391 Resin-based composite - one surface, posterior . 6 D2392 Resin-based composite - two surfaces, posterior . 8
HERE ARE OUR 2018 FORMULAS FOR PANTONE COLORS: Visit our blog post for more variations on these pantone colors: 2018 Pantone Color Formulas using Nunn Design 2-Part Resin and Opaque Pigments SHOP NUNN DESIGN SUPPLIES: Nunn Design 2-Part Resin Kit Resin Mixing Cups Resin Stir Stick Narrow Resin Stir Stick Wide Castin' Crafts Opaque Pigments
Level 4 IS Business Analyst Minimum Standards and Grading Criteria This paper defines the minimum requirements for the knowledge, skills and behaviours defined in the standard, which are required for a pass. It also defines the criteria to be used for awarding the grade for merit or distinction. This paper should be read in conjunction with the Standard and Assessment Plan for the Level 4 IS .
