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Choosing and Using Permanent Luting Cements - Wayne Flack

Sullivan-Schein Dental is an ADACERP recognized Agents:Agents that bond, seal, or cementparticles or objects together. 1 Background Fifty years ago dentists had arelatively simple time Choosing Permanent lutingcements and indirect restorative materials goldcrowns and zinc phosphate cement ! Howcomplicated things have become in the interveningyears. Dental manufacturers have responded to thedemands of the market by providing more naturallooking, esthetic, and metal-free restorativematerials. Although zinc phosphate Cements , usedin dentistry for well over 100 years,2may have beenadequate for Luting mechanically retentive metal-based restorations, the low strength, poor esthetics,difficult mixing protocol, potential for sensitivity,limited adhesion, and high solubility3makes them apoor choice for many modern clinical situations.

Metal/PFM crowns/bridges Composite crowns/ strengthened-core ceramic pressed ceramic Composite or ... porcelain or all-composite crowns, inlays, onlays, and veneers, must be adhesively ... Choosing and Using Permanent Luting Cements ...

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Transcription of Choosing and Using Permanent Luting Cements - Wayne Flack

1 Sullivan-Schein Dental is an ADACERP recognized Agents:Agents that bond, seal, or cementparticles or objects together. 1 Background Fifty years ago dentists had arelatively simple time Choosing Permanent lutingcements and indirect restorative materials goldcrowns and zinc phosphate cement ! Howcomplicated things have become in the interveningyears. Dental manufacturers have responded to thedemands of the market by providing more naturallooking, esthetic, and metal-free restorativematerials. Although zinc phosphate Cements , usedin dentistry for well over 100 years,2may have beenadequate for Luting mechanically retentive metal-based restorations, the low strength, poor esthetics,difficult mixing protocol, potential for sensitivity,limited adhesion, and high solubility3makes them apoor choice for many modern clinical situations.

2 Toimprove this a succession of new cementtechnologies were developed to satisfy the higherdemands of these newer restorations. As a result,today s clinician faces a myriad of combinations ofrestorative materials, Luting Cements , and clinicalsituations, some of which may be incompatible witheach other. This article hopes to help practicingclinicians choose and use Permanent cementsreliably and Types At the highest level, all permanentcements can be put into one of two broadcategories, Luting Cements and bonding Cements (adhesive Cements ). Luting Cements are those thatachieve retention by filling in gaps between therestoration and the tooth and setting, , turninginto cement . Adhesion, if any, is a surfacephenomenon comprised of wetting and micro-mechanical interlocking. Bonding Cements differfrom Luting Cements in two ways.

3 First, they arestronger so for a given level of gap filling they willoffer greater retention and superior support for weakrestoration types. In the case of exposed margins,the increased strength leads to improved wearresistance, especially important when seating inlaysor , they have much higheradhesion, extending beyond a surface adhesion to tooth structure there may bepenetration into the smear layer, if present, or intodentin tubules. Bonding to the restoration may beachieved by the aid of primers to allow for chemicaladhesion to inorganic filler or metal oxides. Luting Cements , because they are used almostexclusively under metal-based restorations, are self-cured. Bonding Cements may be self-cured, dual-cured, or there are four major classes of Luting cementswith a significant presence in the market zincphosphate, polycarboxylate, conventional glassionomers, and resin-modified glass is only one type of bonding cement ,composite resin Cements (of which there are threesubtypes).

4 The main development trends in newcement products are very clear, stronger, lesssoluble, more adhesive, more esthetic, and easier touse. Table 1 lists the main advantages anddisadvantages of the different types as well as theleading product brands6 in each class. Table 2presents a list of recommended Cements accordingto restoration oldest technologies, zinc phosphate,polycarboxylate, and conventional glass ionomers,share two advantages a long, well-understoodclinical history and low price. When used properlyand where indicated, each can give excellentresults. The list of disadvantages is much longerDistributed 1. Overview of CementsCement TypeLeading Brand NamesPrimary Strengths Primary WeaknessesZinc PhosphateFleck s -Long clinical experience-Occasional postoperative sensitivity-High solubility-Low hardnessPolycarboxylateDurelon -Low fluoride ion release-High solubility-Low postoperative sensitivity-Low adhesion-Low hardnessConventional Glass IonomerKetac Cem-Fluoride ion release-Occasional postoperative sensitivityFuji 1 -Adhesion to tooth and metal-Some moisture sensitivity-Ease of use-Marginal solubility-Good routine cementResin-Modified Glass IonomerRelyX Luting cement -Fluoride ion release-Swelling or linear expansionRelyX Luting Plus cement -Adhesion to tooth and metal-Moisture sensitive powderFuji PLUS -Low or no marginal solubilityFujiCEM -Ease of use-Low postoperative sensitivity-Good routine cementComposite-Resin -Total Etch

5 cement SystemsVariolink II-High strength-Technique sensitiveCalibra -Esthetics-Requires use of separate etchant and/orC&B Metabond -Low solubilityprimer and veneer cement -High adhesion-Potential for postoperative sensitivity-Difficult cleanup-Self-Etching Primer cement SystemsPanavia F-High strength-Difficult cleanup-Low solubility-Separate primer required-High adhesion-No etching required on dentin-Low postoperative sensitivity-Self-Adhesive cement SystemsRelyX Unicem cement -High strength-Limited clinical history-High adhesion-Available only in capsule delivery-Esthetics-Ease of us-Low postoperative sensitivity-Low solubility-Easy clean up-Capsule delivery systemTable 2. Indications Chart cement RecommendationsAll-zirconia or all-aluminaTraditional feldspathic orMetal/PFM crowns/bridgesComposite crowns/strengthened-core ceramic pressed ceramic Composite orinlays/onlaysinlays onlayscrowns/bridgescrowns/inlays/onlays ceramic veneersZinc PhosphateX1 PolycarboxylateX1 ConventionalGlass IonomerX1X2 Resin-Modified Glass IonomerX1X2 Composite-Resin CementX3XX XX41 For nonretentive preps or for Maryland bridges, composite-resin Cements should be used to improve these restorations, esthetic and wear resistance needs must be assessed to determine if the GI-based Cements will be sufficient and complement the not, composite-resin cement should be used.

6 Also, if enough mechanical retention is not available, composite-resin cement should be most composite-resin Cements , with the exception of some self-etching-based systems ( , RelyX Unicem), this is typically more work and effort than is neededfor metal-based restorations that have sufficient built in retention. It also may increase the potential for patient sensitivity and difficulty in only systems are preferred to maximize potential for color stability. Self-cure systems or light-curable base components from dual-cure systems havegreater potential for color change over high solubility, low strength,hand-mixing powders and liquids (althoughsome are available in unit-dose capsules),poor esthetics, and low or no adhesion totooth structure. Their main applicationsare for metal or metal-supportedrestorations with mechanically retentivepreps.

7 Because of their low strength andlow adhesion, they are contraindicated formost ceramic-based and all composite-based restorations. Polycarboxylatecements were state of the art when theywere introduced about 40 years ago, butnow find significant use as long-termprovisional Cements . Reality categorizespolycarboxylate Cements under of these three typescomprise about one-third of applications,and are seeing consistently eroding fourth and most dominant lutingcement type, the resin-modified glassionomers, were commercialized in 1994with the introduction of Vitremer LutingCement from 3M ESPE (renamed RelyX Luting cement in 1999). Other productssoon followed. As the description implies,from a technological perspective thesecements were formulated by addingmethacrylate monomers and cure initiatorsto traditional glass ionomer Cements .

8 Insome cases, the polyacrylic acids aremodified to include curable methacrylategroups. These modifications broughtsignificant improvements to Luting Cements ,including easy cleanup, improvedadhesion to tooth structure to aid inretention, higher strength (also to aidretention), very low solubility to virtuallyeliminate washout from margins, and verylow rates of postoperative sensitivity whilemaintaining high levels of fluoride reports based on clinicalobservations have linked resin-modifiedglass ionomer Luting Cements with post-cementation fracture of all-ceramic , with the exception of oneproduct, since discontinued, this problemmay not be 9 Recentimprovements, focused on improving easeof use and reliability, lead to theintroduction of paste/paste technologies,and these products are seeing thestrongest growth. Although the strength and adhesion isimproved compared to the other lutingcements, from a clinical perspective theseimprovements are not significant andresin-modified glass ionomers do notexpand the indications over other lutingcements.

9 Although some manufacturersindicate them for use with porcelain andcomposite inlays, the conservative clinicianwill limit their use to metal, metal-based,and core-strengthened, glass-freeceramic10restorations with retentive preps. Composite Resin Cements As their namesuggests, these Cements are modifiedcomposite restorative materials and havethe advantages of high strength, highadhesion, low solubility, and allows them to be used with weak,esthetic restoration types such as glass-ceramics and indirect composite or incases where there are concerns aboutretention. Although two-part, paste/paste,dual-cured formulations are most common,they may be self-cured, dual-cured, orlight-cured and hand-mixed, auto-mixed, orcapsule mixed. Like direct-compositerestorative materials, most need to beused with bonding systems. There arethree subtypes total-etch systems, self-etching primer systems, and total-etch systems have three mainsteps.

10 First, an acid etch is applied to thetooth and then rinsed and lightly dried(overdrying can lead to sensitivity). Next,a bonding agent is applied, frequently inseveral coats, and then cured. Thebonding agent may be light-cured or atwo-part, self-cured system. Finally, thecement is mixed (for self-cured and dual-cured), applied to the restoration, seated,cleaned up, and cured. Most total-etchsystems are dual-cured or are only indicated under all-ceramicor composite restorations. In the self-etching primer systems, the acid etchingand bonding steps are replaced with aself-etching primer, typically a two-partsystem that needs mixing. There areenough differences in protocol betweenthe different Cements brands that readingproduct instructions thoroughly is importantas well as Using the adhesive or primerand cement from the same total-etch and self-etching primercements have been technique systems are hydrophobic and lackmoisture tolerance.


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