1: This is a rare photograph of the new dentin bridges after removal of the composite, pins and zinc phosphate cement. for use as a liner or base under composite, amalgam, metal and ceramic restorations. (B) Two-paste system (Prisma VLC Dycal). replaces the need for a dentin sealer. Calcium hydroxide is a strong alkali, which can be formed by the reaction of calcium oxide. ANGELA C. ANDERSON MD, in Haddad and Winchester's Clinical Management of Poisoning and Drug Overdose (Fourth Edition), 2007, Calcium hydroxide, or lime, is a common cause of alkali injury in the construction workplace. All of the calcium silicate MTA-like formulations leached large amounts of Ca and OH ions, more than conventional calcium hydroxide resin–containing materials. The base paste of a typical product contains calcium tungstate, tribasic calcium phosphate, and zinc oxide powders suspended in a glycol salicylate liquid. Two pasts, the reaction result in the formation of amorphous calcium disalicylate. Calcium hydroxide (CaOH) has two components: a base and a ‘catalyst’. Dycal was better adapted to the cavity floor than Prisma VLC Dycal. $17.20 $ 17. The opacification of Bowman's membrane observed in mild exposures is secondary to precipitations of calcific material. Calcium hydroxide. HYDROXYLINE and HYDROXYLINE TC - Calcium Hydroxide Cavity Liner Hydroxyline's thin 'varnish' film forms a chemical and physical barrier that seals tubules and protects the pulp from acids in cements and acid etching solutions. NLM Get it as soon as Tue, Jan 12. 1990 Oct;18(5):263-70. doi: 10.1016/0300-5712(90)90026-b. Criteria for assessment of healing include absence of intracanal bleeding or exudates, absence of symptoms, tactile evidence of a barrier and radiographic evidence of bone resolution adjacent to the site of calcific repair (Fig. • Prevents microleakage — Today’s RMGI liner/base materials offer a stronger bond to the dentin than traditional glass ionomers, resulting in less leakage under the composite. Solubility is required for release of calcium hydroxide and sustained activity. In the second group a new light-cured calcium hydroxide product (Prisma VLC Dycal, De Trey Dentsply) was used. 1991 Apr;19(2):71-9. doi: 10.1016/0300-5712(91)90093-e. J Biomater Appl. The catalyst contains barium sulfate and titanium dioxide as radiopacifiers in addition to resin, isobutyl salicylate, and aerosol R 972. RMGI liners are a better choice for general lining of cavities because of their fluoride release, decreased solubility, and superior mechanical properties. 1.8-3.0) approached that of bone-like carbonate apatite more than that of the other calcium hydroxide–based materials. • Composite • Amalgam • Ceramic • Metal CONTRAINDICATIONS Pulp Protection: Vitrebond liner/base is not indicated for direct pulp capping. [18,21] According to one study, TheraCal LC is a calcium … By reaction with CO2 from the air, hydrated lime sets to form calcium carbonate and is therefore not a hydraulic binder. The restorations were completed with an acid-etched, incrementally placed composite resin. Studies have shown that calcium hydroxide “softens” under amalgam and resin-based composite restorations. Fig. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. URL: https://www.sciencedirect.com/science/article/pii/B9780323608268000213, URL: https://www.sciencedirect.com/science/article/pii/B9780444533494002806, URL: https://www.sciencedirect.com/science/article/pii/B9780323478212000081, URL: https://www.sciencedirect.com/science/article/pii/B9780323064897000102, URL: https://www.sciencedirect.com/science/article/pii/B9780702031564000115, URL: https://www.sciencedirect.com/science/article/pii/B9780702031564000127, URL: https://www.sciencedirect.com/science/article/pii/B9780702031564000085, URL: https://www.sciencedirect.com/science/article/pii/B9780702031557000084, URL: https://www.sciencedirect.com/science/article/pii/B9780721606934500207, Cohen's Pathways of the Pulp (Tenth Edition), 2011, Kevin J. Donly, ... Fernando L. Esteban Florez, in, Polymers for a Sustainable Environment and Green Energy, Polymer Science: A Comprehensive Reference, Craig's Restorative Dental Materials (Fourteenth Edition), Obturation of the Cleaned and Shaped Root Canal System, Cohen's Pathways of the Pulp (Tenth Edition), Harty's Endodontics in Clinical Practice (Sixth Edition), Haddad and Winchester's Clinical Management of Poisoning and Drug Overdose (Fourth Edition), The Journal of the American Dental Association. In the first group a chemically cured calcium hydroxide (Dycal, De Trey Dentsply, Konstanz, FRG) was placed as a base. With a primary energy demand of 4.22 MJ kg−1 and a CO2 equivalent of 0.93 kg−1, hydrated lime is, from the ecological point of view, similar or slightly less favorable as compared to Portland cement.203, In Craig's Restorative Dental Materials (Fourteenth Edition), 2019. using calcium hydroxide liners under RMGI is the best w ay . Which supplemental material is contraindicated under composite … However, some advocate resin-modified glass ionomer (RMGI), some are using calcium hydroxide, and others are using some new regenerative materials. Although calcium hydroxide causes eye injuries that tend to be less severe than those of ammonium or sodium hydroxide, it promotes corneal opacification more quickly than other alkalis.7 Mild lime burns typically cause a frosted or ground-glass opacity superficially at the level of Bowman's membrane. A light-cured calcium hydroxide liner consists of calcium hydroxide and barium sulfate dispersed in a urethane dimethacrylate resin, similar to what is used in some dental composites. (A) Visible light–cured system (Dycal). Traditionally, dental schools have taught that caries removal was always followed by the placement of a liner, typically a glass ionomer or calcium hydroxide. Calcium hydroxide cements are supplied in a visible light–cured system (Fig. Commercial products include Sealapex (SybronEndo), a calcium hydroxide-containing polymeric resin, Apexit Plus (Ivoclar Vivadent, Schaan, Liechtenstein) and epoxy-based Acroseal (Septodont, Saint-Maur Cedex, France). The first method of capping exposed pulps, using gold foils, was described by Pfaff in 1756. The latter is preferable because it will allow further dissolution of residual organic debris. The restorations were completed with … For further guidance see Andreasen & Andreasen (1994). Calcium hydroxide is applied as a thick, creamy suspension in sterile water, saline, and a variety of other, viscous or oily vehicles.82,83, N.P. The alkaline pH aids in preventing bacterial invasion. Marginal adaptation of Class V restorations using different restorative techniques. 20. dentin. The important properties of calcium hydroxide cements are mechanical and thermal properties, solubility, and pH. If it is found that a substantial amount of the paste has been resorbed (Fig. Chandler, in Harty's Endodontics in Clinical Practice (Sixth Edition), 2010, Calcium hydroxide-based sealers have been developed on the assumption that they preserve the vitality of the pulp stump and stimulate healing and hard tissue formation at the apical wound. The dentine bridge is not formed by calcium from the material, but instead from the underlying tissues.105,106 With resin-based composite, MTA and hard-setting calcium hydroxide, the bridge forms close to the material; however, with calcium hydroxide powder and water mixes the barrier is formed with an intervening zone of necrosis.99 The dentine bridges formed under calcium hydroxide are often imperfect with numerous tunnel defects;107,108 this is in contrast to MTA where tunnel defects are not seen102 (Figs 5.2 & 5.3). Materials techniques for lining composite resin restorations: a critical approach. This site needs JavaScript to work properly. INTRODUCTION Calcium hydroxide is considered to be the cavity base of choice under composite resin restorations in the UK. Apexit and Apexit Plus (Ivoclar Vivadent, Schaan, Liechtenstein) consist of an activator (disalicylate, bismuth hydroxide/bismuth carbonate, and fillers) and a base (calcium hydroxide, hydrated colophonium, and fillers). Amazon's Choice for calcium hydroxide. The duration of dressing should be balanced against the possible damage incurred on the mechanical properties of dentine. The base is composed of calcium tungstate, tribasic calcium phosphate and zinc oxide. USA.gov. A calcium hydroxide lining material which does not . Bargrizan M, Mirkarimi M, Rezamand M, Eskandarion S. J Dent (Tehran). The pH of commercial products has been measured at between 9.2 and 11.7. HHS Vitrebond Liner/Base is not indicated for direct pulp capping. For renders and mortar-coating applications, quite often Portland cement is combined with hydrated lime due to its plastic properties, to achieve good workability and to reduce the brittleness of the cement mortar. However, as amalgam has been phased out as a restorative material of choice and resin composites have moved in, questions have arisen as to the validity of this practice. If used as a routine antibacterial dressing, then 7 days are sufficient. Therefore, part of the management of these injuries involves the use of disodium edetate (EDTA) to extract the entrapped calcium (see section on Special Management Considerations).12 More severe injuries occur when the pH is 12 or higher and are often associated with stromal opacification and corneal anesthesia.8 Stromal opacification is a result of damage to stromal components and is not responsive to EDTA treatment. As hydrolysis occurs, occlusal forces cause apical displacement of the restoration, leading to discrepancies and breakdown at the restoration margin. Figure 21.1. Both the acid used for etching and the one in GIC(which is also used as a liner). Some speakers and authors are promoting use of flowable resin-based composites as liners under composites. The null hypothesis tested was that the combination of calcium hydroxide, resin-modified glass ionomer, and dentin adhesive used as pulp protection in composite restorations would not result in a greater axial gap than that obtained with hybridization only. A replica was made of each half-tooth. Calcium hydroxide is spun into the canal to facilitate the removal of the tissue in the irregular defect at the next visit. Stimulates the production of reparative dentin C. Functions as a thick base to support extensive restorations D. Consists of a resin in an organic solvent In the first group a chemically cured calcium hydroxide (Dycal, De Trey Dentsply, Konstanz, FRG) was placed as a base. Commercial hydrated lime is a dry powder obtained by treating quicklime (see calcium oxide) with sufficient water to satisfy its chemical affinity for water, thereby converting the oxides to hydroxides. Since calcium hydroxide exists in a particulate form, it is commonly retained in the eye (particularly beneath the upper eyelid) and provides a continuous source of exposure. They usually result in a significant loss of epithelium, but rarely affect the underlying stroma. From: Cohen's Pathways of the Pulp (Tenth Edition), 2011, Kevin J. Donly, ... Fernando L. Esteban Florez, in Pediatric Dentistry (Sixth Edition), 2019. Contain radiopaque fillers. It was a powder liquid material that I used on deep restorations as a thermal insulator under my amalgam restorations. Calcium hydroxide sealers were developed for therapeutic activity. Light cured product Urethane dimethacrylate & calcium hydroxide + low- … A catalyst paste containing calcium hydroxide, zinc oxide, and zinc stearate in ethylene toluene sulfonamide reacts with a base paste containing calcium tungstate, calcium phosphate, and zinc oxide in glycol salicylate to form an amorphous calcium disalicylate. A There are many choices for bases and liners, and it is inter… Calcium hydroxide is a compound with many uses, from making cement to adding crunchiness to pickles. The calcium soaps precipitate and make penetration of the cornea more difficult. Calcium Hydroxide CALCIUM HYDROXIDE or HYDRATED LIME. Material constituents/composition Calcium Hydroxide Generates a relatively high pH environment around area surrounding the cement due to calcium hydroxide leaking out thus making it bactericidal. 8.177) more frequent dressings with stiffer pastes may be required. QI’m perplexed by the changing use of liners and bases under restorations, both direct and indirect. Unfortunately, these actions have not been demonstrated. 1, 2 The results are attributed to hydrolysis of the calcium hydroxide by fluid contamination from dentinal tubules and microleakage. Which is not a unique chracteristic of calcium hydroxide? Calciobiotic root canal sealer (CRCS) is a zinc oxide–eugenol sealer with calcium hydroxide as one ingredient. CALCIUM HYDROXIDE. This is inconsistent with the purpose of a sealer. A preliminary scanning electron microscope (SEM) study was carried out to investigate how the adaptation of two calcium hydroxide bases (one chemically cured, one light cured) was affected by the polymerization contraction of a supervening light-cured composite resin restoration. ... (SBS) of light cure MTA and light cure calcium hydroxide with nanofilled composite. Presentation: Composite pack: Cavity Lining of 10 ml. require mixing, sets rapidly and adheres firmly to dentine. Please enable it to take advantage of the complete set of features! Pure Calcium Hydroxide [Slaked Lime] ⊘ Non-GMO Gluten-Free ☮ Vegan - … In dental school I was introduced to Calcium Hydroxide. The antibacterial action of calcium hydroxide makes these cements useful in indirect pulp-capping procedures involving carious dentin.  |  So when I stopped doing amalgams (the day I graduated dental school) I made the switch to Vitrebond. It has been shown that the frequency of change may enhance the effectiveness in periapical resolution but the benefit may be marginal. WILLIAM T. JOHNSON, JAMES C. KULILD, in Cohen's Pathways of the Pulp (Tenth Edition), 2011. Dycal appeared to be more friable, and occasionally exhibited marked disorganization as a result of these procedures. But is it safe? Get the latest public health information from CDC: https://www.coronavirus.gov, Get the latest research information from NIH: https://www.nih.gov/coronavirus, Find NCBI SARS-CoV-2 literature, sequence, and clinical content: https://www.ncbi.nlm.nih.gov/sars-cov-2/. K Gulabivala, Y-L Ng, in Endodontics (Fourth Edition), 2014. Some solubility of the calcium hydroxide is necessary to achieve its therapeutic properties, although an optimum value is not known. It was thought that these sealers would exhibit antimicrobial activity and have osteogenic–cementogenic potential. In the first instance, the dressing is changed at 2–4 weeks to evaluate the degree of loss or contamination of the calcium hydroxide. Typical dosage of hydrated lime in many dry mortars is 5–30 wt.% on cement. and Thinner of 10 ml. It is a white powdered or granular solid that is used to make plaster, cement, mortar, and whitewash. It is important then to use sufficient water and a small file to negotiate past it. Fig. It also allows a further opportunity to irrigate the canal with sodium hypochlorite and reduce the bacterial and organic contamination. Visible light–cured calcium hydroxide preparations have demonstrated clinical success3 and may be less susceptible to hydrolysis. What is currently the best material to use when bases or liners are necessary? We use cookies to help provide and enhance our service and tailor content and ads. The use of weak acids, such as EDTA or citric acid, significantly enhances its removal leaving a cleaner canal wall as viewed by SEM, if this is considered desirable. Copyright © 2021 Elsevier B.V. or its licensors or contributors. The duration of dressing with calcium hydroxide is dependent upon the objective of dressing. Calcium hydroxide A. Place the Vitrebond liner/base over the calcium hydroxide and surrounding dentin to seal and protect the exposure. Fillers such as calcium tungstate or barium sulfate provide radiopacity. Some clinicians use Dycal as a liner under composite in deep cavities as the acid is likely to irritate the pulp. I will write about that some other day. Use it under both temporary and permanent cementation to protect the pulp.  |  Radiopacity is provided by calcium tungstate, or in some cases by barium sulphate fillers. The specimens were sectioned vertically and debrided. Would you like email updates of new search results? For a group of five commercial products, compressive strengths ranged from 6.5 to 14.3 MPa at 10 minutes to from 9.8 to 26.8 MPa at 24 hours. It also has a function for direct or indirect pulp capping (see Chapter 9), but will only be discussed in this chapter as a dental liner. Free calcium hydroxide in excess of that necessary to form the calcium disalicylate stimulates secondary dentin in proximity to the pulp and shows antibacterial activity. Epub 2011 Dec 20. Calcium hydroxide is a dental liner that stimulates the formation of irregular secondary (tertiary) dentine. 2011 Fall;8(4):178-85. The Ca/P atomic ratio of the coating (range approx. If a pulp exposure occurs, cover the exposure with a calcium hydroxide material. Calcium hydroxide (self-cured) liners have low values of tensile strength, compressive strength, and elastic modulus, compared with high-strength bases. Place the Vitrebond liner/base over the calcium hydroxide and surrounding dentin to seal and protect the exposure. 1,2 The results are attributed to hydrolysis of the calcium hydroxide by fluid contamination from dentinal tubules and microleakage. The catalyst is composed of calcium hydroxide, zinc oxide and zinc stearate. Many studies on calcium hydroxide [Ca(OH)2] as a chemical heat storage material have been conducted. Occlusal cavities were prepared in 40 sound extracted human premolars, divided into two equal groups. By continuing you agree to the use of cookies. Calcium hydroxide cements. The use of calcium hydroxide to induce calcific repair at the periapex requires longer periods of dressing. Ca-Lok Flowable Adhesive Calcium Base/Liner Light cure calcium filled resin with adhesion for all deep cavity preparations ... Calcium Hydroxide Cavity Liner in resin matrix Place under Amalgam and Composite restorations:  |  NIH 21.1A) and a two-paste system (Fig. Studies have shown that calcium hydroxide “softens” under amalgam and resin-based composite restorations. Calcium hydroxide cements are used for lining specific areas of deep cavities or for direct pulp capping. However, Calcium Hydroxide was not ideal under composite restorations. Research has shown that these cements can stimulate the formation of protective secondary dentin bridges when applied to direct pulp exposures. For centuries, hydrated lime has been by far the most important binder in mortars, but today it is largely substituted by hydraulic binders like cement, which set faster and develop much higher strength. The solubility of calcium hydroxide bases has been measured in several solvents for various periods of immersion and has been found to be significant. An ultrasonically activated file is very effective at removing calcium hydroxide dressings. H. Lutz, ... W. Huster, in Polymer Science: A Comprehensive Reference, 2012, Hydrated lime (Ca(OH)2) is produced by burning limestone at high temperatures with subsequent controlled quenching with water. If the oxide is treated with only sufficient water to make it crumble to a fine, white, dry powder slaked lime is produced. Calcium hydroxide may also be used as a long-term dressing or as a short-term root filling if treatment cannot be completed for logistical reasons or if the tooth needs to be left on review to assess the possible outcome of treatment, e.g. The low elastic modulus of calcium hydroxide cavity liners restricts their usage to specific areas not critical to the support of restorations. In the second group a new light-cured calcium hydroxide product (Prisma VLC Dycal, De Trey Dentsply) was used. 1991 Feb;19(1):24-32. doi: 10.1016/0300-5712(91)90032-t. J Dent. Calcium hydroxide liners are mostly used in direct pulp capping and specifically in deep areas of a cavity preparation, but not for general lining of an entire pulpal flow. 2: Multi-Cal can also be used for dentin bridge formation in direct pulp capping, pulpal curettage and vital calcium hydroxide pulpotomy procedures. Indications for Use: As a lining under filling materials. The dressing may then be left in place and healing reassessed at 3–4-monthly intervals. resin. J Dent. HiMedia GRM718-500G Calcium Hydroxide, Purified, 500 g. 4.6 out of 5 stars 37. Calcium hydroxide is relatively easily removed by washing and irrigating with water or sodium hypochlorite. The mechanism of both calcium hydroxide and MTA appears to be the dampening of pulpal inflammation, providing an environment conducive to repair. [18,19,20] The aforementioned light curing pulp capping materials generally contain calcium hydroxide, but nowadays a calcium silicate containing light curing pulp capping agent has been introduced. The effect of flowable resin composite on microleakage in class V cavities. The alkaline pH aids in preventing bacterial invasion. The marginal adaptation at these two interfaces was classified into three categories according to the extent of the gaps that were observed. D. Ørstavik, in Harty's Endodontics in Clinical Practice (Sixth Edition), 2010, Calcium hydroxide has reached a unique position as a dressing in endodontics.79 After its successful clinical application for a variety of indications,18,80 multiple biological functions have been ascribed to calcium hydroxide.81 Its primary function is probably antibacterial in most clinical situations, with the added benefits of cauterizing activity and high pH; also in the consistency of a paste, it physically restricts bacterial colonization of the canal space. 21.1B). A composite material made up of a combination of particles of various sizes is referred to as a _____. Generally, calcium hydroxide undergoes a dehydration reaction (heat storage operation) efficiently at about 400 °C or higher. Fortunately, it penetrates the eye much more slowly than ammonium hydroxide or sodium hydroxide, forming insoluble calcium soaps during saponification of cell membrane fatty acids. Prisma VLC Dycal base was found to be pulled away from the dentine floor of the cavity as a result of an apparent adhesion to the composite resin during polymerization contraction. Microleakage and Micrographic Evaluation of Composite Restorations with Various Bases over ZOE Layer in Pulpotomized Primary Molars. Although setting times vary between 2.5 and 5.5 minutes, strength of these cements continues to increase over a 24-hour period. Cal Hydro is a totally different story all together. perio–endo cases (Fig. Clipboard, Search History, and several other advanced features are temporarily unavailable. Mixed Class V restorations: the potential of a dentine bonding agent. H.F. Duncan, in Harty's Endodontics in Clinical Practice (Sixth Edition), 2010, Calcium hydroxide has been established as the gold standard pulp capping/ partial pulpotomy material over the last 50 years.94–99 Resins have been investigated as alternatives but they have, generally, been dismissed as not matching the performance of calcium hydroxide.100,101 Over the last 10 years, Mineral Trioxide Aggregate (MTA) has emerged as the material of choice for vital pulp therapy.102,103. Calcium hydroxide cavity liners are provided as pastes that set to a hard mass when mixed. Consequently, lime causes many of the superficial complications seen following other strong alkali injuries, but deeper structures, such as the iris and lens, are routinely spared.8. Sometimes, the calcium hydroxide may become very well compacted in a narrow canal giving the impression of a blockage. Thereafter, bioactive molecules are liberated in the dentine which stimulate differentiation of pulpal stem cells and also further control the inflammatory response; this allows the pulp to repair.97,104 Pulpal stem cells have the ability to develop into odontoblast-like cells which allows the pulp to regenerate and form dentine bridges across the deficit. Dressing and irrigation are continued until weeping is stemmed. 2007 May;32(3):198-207. https://doi.org/10.5395/JKACD.2007.32.3.198 The catalyst paste contains calcium hydroxide, zinc oxide, and zinc stearate powders in ethylene toluene sulfonamide liquid. ... On what tooth structure is calcium hydroxide place? 8.179) or orthodontic cases under treatment. J Dent. The interfaces between composite resin/base and base/dentine were viewed and photographed in the SEM. Disorganization of the resin-bonded Prisma VLC Dycal was minimal even after acid etching the enamel, sectioning and ultrasonic debridement. Park NH, et al. RMGI liner/base products seal the tooth and strongly bond to the restoration to reduce the incidence of microleakage between the tooth and the restoration. Clearly the use of acid-etching procedures and varnish in the presence of calcium hydroxide liners must be done with care. A. Enamel B. Cementum C. Dentin ... cavity walls and the margin of the cavity preparation under amalgam restorations? 8.178). We'll go over all the ways that calcium hydroxide … COVID-19 is an emerging, rapidly evolving situation. Sealapex (SybronEndo) is a catalyst/base system. The base contains zinc oxide, calcium hydroxide, butyl benzene, sulfonamide, and zinc stearate. J Korean Acad Conserv Dent. These should be gauged on the basis of the requirement of the case. In this study, we aimed to lower the dehydration reaction temperature and increase the dehydration reaction rate to expand the applicability of calcium hydroxide … There is no definitive guidance on the duration of dressing in case of dental trauma and root resorption. If the objective is to arrest a weeping canal, then it may be necessary to dress with a stiffer paste for a period of at least 14 days. Calcium Hydroxide Cement Used for direct & indirect pulp caping beneath composite restorations. In addition to aiding pulp healing, these resin-based materials serve as an intermediary layer in the cavity walls similar to that of flowable composite. the main ingredient in varnish is. It also has a unique effect of initiating calcification and stimulating the formation of secondary dentine due to an irritation effect of the pulp tissues by the cement. It will prevent thermal and 'pulp' shock. 5 Laboratory research has demonstrated their sealing ability to be similar to zinc oxide-eugenol sealers25 although it remains to be seen whether during long-term exposure to tissue fluids they maintain their integrity, since calcium hydroxide is soluble and may leach out and weaken the remaining cement.24. If a pulp exposure occurs, cover the exposure with a calcium hydroxide material. As hydrolysis occurs, occlusal forces cause apical displacement of the restoration, leading to … FREE Shipping on orders over $25 shipped by Amazon. When calcium hydroxide is used, a less soluble high-strength base material such as glass ionomer may be placed to overlie the calcium hydroxide. The ingredients responsible for setting are calcium hydroxide and a salicylate, which react to form an amorphous calcium disalicylate. National Center for Biotechnology Information, Unable to load your collection due to an error, Unable to load your delegates due to an error. On what tooth structure is calcium hydroxide placed? Studies have shown that calcium hydroxide “softens” under amalgam and resin-based composite restorations.1,2 The results are attributed to hydrolysis of the calcium hydroxide by fluid contamination from dentinal tubules and microleakage. 1987 Jan;1(3):373-81. doi: 10.1177/088532828600100405. It may be concluded that there are positive advantages to the routine dressing of root canals with calcium hydroxide. Incompletely formed apices can take up to 24 months before a complete barrier forms, but most are complete by 9 months. The material was first introduced as a base by Herman (1930), who proposed its beneficial action as a pulp-capping material. Although the material choice may favour the outcome of treatment, healing of pulpal exposures is critically dependent on the capacity of the material or surface restoration to prevent microleakage.25,35 Therefore, regardless of the capping agent used, prevention of microleakage is critical. Cannot be placed under direct composite resins because it will inhibit polymerization B.