TheraCal LC: Your Most Common Questions Answered

Key Takeaways 

• TheraCal LC is a light-cured, resin-modified calcium silicate liner indicated for direct and indirect pulp capping and as a protective liner under composites, amalgams, cements, and other bases. 
• In lab testing, TheraCal LC released more calcium and was less soluble than calcium hydroxide liners such as Dycal, so it’s built to stay put under a restoration instead of slowly dissolving.* 
• RMGI liners seal well but aren’t meant to sit on the pulp. HEMA and fluoride release have both been linked to pulp cell toxicity in lab studies.^1–6 
• Per gram, TheraCal LC costs more than Dycal, Lime-Lite Enhanced, or Vitrebond Plus. Per use, it’s roughly $3 to $4, and you save time with no mixing, a 20-second cure, and immediate bonding. 

Prefer to watch? Nate Tarantelli answers every question below in our TheraCal LC video. 

▶ Watch the Full TheraCal LC Video 

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If you’re still reaching for Dycal on deep caries, layering an RMGI over it, or keeping one material for indirect caps and another for exposures, you’re not doing anything wrong. You’re doing what dentistry has done for decades: picking the compromise you can live with. 

TheraCal LC is built to remove that compromise. It’s a light-cured, resin-modified calcium silicate liner you can place directly on an exposure or over deep dentin, cure in 20 seconds, and bond over right away. It releases calcium like a calcium hydroxide liner, and because it’s resin-based, it has the low solubility typical of resin materials. 

BISCO has spent 45 years studying how materials behave at the tooth interface, and pulp protection is where that chemistry gets personal: sometimes your margin for error is half a millimeter of dentin. This article is an honest look at TheraCal LC: how it works, how it compares to calcium hydroxide, glass ionomer, and resin-modified glass ionomer (RMGI) liners, what the research does and doesn’t show, and what it really costs per use. 

What Is a Resin-Modified Calcium Silicate Liner? 

Think of it as a hybrid with a division of labor. The tricalcium silicate particles, from the same chemical family as MTA, handle the chemistry: in the presence of moisture, they release calcium and hydroxide ions, creating an alkaline environment. The resin, a hydrophilic monomer matrix, does the practical work: it sets on command under your curing light and gives your adhesive something to grab. 

TheraCal LC is indicated for direct pulp capping, indirect pulp capping, and as a protective liner under composites, amalgams, cements, and other base materials. That’s one syringe for jobs that used to take two or three products. 

How Does a Calcium-Releasing Liner Actually Work? 

Once it’s placed, the calcium silicate starts exchanging ions with moisture from the dentin. Calcium and hydroxide ions are released, and the local environment becomes alkaline. Those two properties, calcium release and alkaline pH, are what clinicians look for in a pulp-capping liner. 

How much calcium comes out matters. In a study by Gandolfi and colleagues, TheraCal released significantly more calcium than both ProRoot MTA and Dycal throughout the test period, and it was less soluble than either one.⁷ Hold onto that second finding. It’s the whole story of the next question. 

Why Not Just Stick with Calcium Hydroxide? 

Calcium hydroxide earned its reputation. It has anchored vital pulp therapy since the 1930s, and it does release calcium. The problem is that it doesn’t stay. Calcium hydroxide liners have high solubility and water sorption, which can soften the material and, under a poorly sealed restoration, let oral fluids partially or completely dissolve it. The literature even has a name for it: “Disappearing Dycal” syndrome.⁸ Calcium hydroxide also doesn’t adhere to dentin or to resin restoratives, which is why current protocols cover it with an RMGI layer.⁸ 

A resin-modified calcium silicate keeps the calcium release and drops the disappearing act. Low solubility means the liner you placed is still there at recall, still sealing.⁷ And because it’s light-cured, you skip the two-paste mix and the wait. 

Can Glass Ionomer or RMGI Liners Do the Same Job? 

They do part of it, and they do that part well. RMGI liners bond chemically to dentin, release fluoride, and provide a reliable seal over moderately deep preps.⁸ Plenty of practices have placed thousands of them with good results. 

But sealing isn’t the same as supporting the pulp. Glass ionomers and RMGIs don’t release calcium, and they aren’t indicated for direct pulp capping. Placed directly on a pulp exposure, they raise two concerns. The first is HEMA, the water-soluble monomer in most RMGIs. It’s the major component released from these materials, and in lab testing it inhibited the growth of human pulp cells.⁹ 

The second is fluoride. In a lab study of eight glass ionomer materials, fluoride release tracked with toxicity to human dental pulp stem cells, and the highest releasers, including Vitrebond, were highly toxic to those cells.² The polyacrylic acid in glass ionomers has also been shown to inhibit apatite formation in lab testing.¹⁰ That’s why the literature advises against RMGIs where remaining dentin thickness is 0.5 mm or less.⁸ 

Animal research points the same direction. In a primate study of bacterially contaminated pulp exposures, TheraCal LC produced dentin bridges with mild inflammation, while the glass ionomer group showed more pulpal necrosis.¹¹ 

Can You Place It Directly on an Exposed Pulp? 

Yes. TheraCal LC is indicated for both direct and indirect pulp capping, including carious, mechanical, and traumatic exposures. Get hemostasis first, then place the material directly on the exposure and extend it at least 1 mm onto the surrounding sound dentin before curing. Because one syringe covers both procedures, you aren’t stocking a separate material for the day a prep goes deeper than you planned. 

How Technique-Sensitive Is a Light-Cured Pulp Capping Liner? 

Every pulp capping material rewards good technique, but this one takes several variables off the table. It’s a single-component flowable delivered from a syringe, so there’s no powder-to-liquid ratio to get wrong and no working-time clock running while you mix. It tolerates a moist field, so you can place it on visibly moist dentin instead of chasing a bone-dry surface. Place it in increments of 1 mm or less and light-cure each one for 20 seconds. For a chairside walkthrough, watch our step-by-step TheraCal LC placement video. 

Is the Resin a Problem for the Pulp? 

It’s a fair question, especially after the HEMA discussion above. But not all resins behave alike. TheraCal LC’s hydrophilic resin matrix was formulated with pulp safety in mind, and when it’s used according to its instructions for use, research supports its safety on vital pulp tissue. We walk through that evidence, including which components the formula leaves out and why, in Is TheraCal LC Toxic to Pulp? Here’s What the Science Actually Shows. 

The short version: the resin lets the material cure on command, seal against microleakage, and accept a bonded restoration. The calcium silicate creates an alkaline pH, which promotes healing and mineralization.^12,13 You get both in one layer. 

What Does the Long-Term Evidence Say? 

TheraCal LC has been in clinical use for well over a decade, and the record has grown with it. In Dental Advisor’s three-year clinical performance report, which covered 378 placements, none of the restorations placed over TheraCal LC debonded or showed marginal discoloration, and the material earned a 98% clinical rating at recall.¹⁴ Those were liners and indirect pulp caps; the report included no direct pulp caps.¹⁴ 

Broader reviews tell a measured story, and it’s worth hearing. A 2022 systematic review and meta-analysis found no difference in clinical success between TheraCal LC and the other pulp capping materials it was compared against, while noting that the certainty of that evidence was low to moderate.¹⁵ In plain terms, it performs on par with the alternatives clinically. Its edge shows up in stability, handling, and how smoothly it fits into your workflow. 

How Many Applications Do You Get From a 1g Syringe? 

About 15 liner applications, or about 20 direct pulp caps. Keep those numbers handy; they change the cost conversation. 

How Much Does a Pulp Capping Liner Cost? 

No point dancing around it: per gram, TheraCal LC is the most expensive material on this list. But you don’t bill per gram. At 12 to 15 liners per syringe, you’re looking at roughly $3.80 to $4.75 per liner, and about $2.85 per direct pulp cap. 

That’s the number to weigh against what cheaper materials cost you in other ways: mixing time, a second RMGI layer over calcium hydroxide, a separate product for the day you hit an exposure, or a liner that may not be there in five years. Value is the price of the material plus everything it asks of you. 

For current pricing, check the TheraCal LC product page. If you order regularly, BISCO Bonding Rewards can help you save on future purchases. 

Is It Worth Switching from Your Current Dental Liner? 

If your current liner does everything you need, keep using it. But if you’re stocking calcium hydroxide for exposures and an RMGI for everything else, waiting on two-paste mixes, or quietly wondering whether that Dycal layer is still there, it’s worth a try. 

Pulp protection shouldn’t force you to choose between durability and speed. Calcium hydroxide and RMGIs each solved part of the problem. TheraCal LC brings the pieces together: sustained calcium release, an alkaline environment that supports healing, low solubility, both direct and indirect pulp capping, and a 20-second cure, all from one syringe.^*,12,13 Instead of adapting your technique to your liner, you get a liner that fits your technique. 

Want to see it all in one place? Watch Nate walk through each answer, start to finish. 

▶ Watch the Full TheraCal LC Video 

Frequently Asked Questions 

Can a Light-Cured Calcium Silicate Liner Be Used for Direct Pulp Capping? 

TheraCal LC can. It’s indicated for direct and indirect pulp capping. Achieve hemostasis, place it on the exposure, extend it at least 1 mm onto sound dentin, and light-cure for 20 seconds. 

Do You Need to Bond Before Placing a Calcium Silicate Liner? 

No. Place TheraCal LC directly on dentin, cure it, then apply your adhesive and restorative immediately. 

How Thick Should a Light-Cured Pulp Capping Liner Be? 

Place TheraCal LC in increments of 1 mm or less, light-curing each increment for 20 seconds. 

Will a Resin-Modified Calcium Silicate Liner Wash Out Like Calcium Hydroxide? 

It’s designed not to. In lab testing, TheraCal LC was less soluble than both Dycal and MTA,7 so it stays in place under the restoration. 

References 

1. Sidhu SK, Nicholson JW. A review of glass-ionomer cements for clinical dentistry. J Funct Biomater. 2016;7(3):16. https://doi.org/10.3390/jfb7030016 
2. Kanjevac T, Milovanovic M, Volarevic V, Lukic ML, Arsenijevic N, Markovic D, et al. Cytotoxic effects of glass ionomer cements on human dental pulp stem cells correlate with fluoride release. Med Chem. 2012;8(1):40-45. https://doi.org/10.2174/157340612799278351 
3. Modena KC, Casas-Apayco LC, Atta MT, Costa CA, Hebling J, Sipert CR, Navarro MF, Santos CF. Cytotoxicity and biocompatibility of direct and indirect pulp capping materials. J Appl Oral Sci. 2009;17(6):544-554. 
4. Stanislawski L, Daniau X, Lauti A, Goldberg M. Factors responsible for pulp cell cytotoxicity induced by resin-modified glass ionomer cements. J Biomed Mater Res. 1999;48(3):277-288. 
5. Selimović-Dragaš M, Huseinbegović A, Kobašlija S, Hatibović-Kofman Š. A comparison of the in vitro cytotoxicity of conventional and resin modified glass ionomer cements. Bosn J Basic Med Sci. 2012;12(4):273-278. 
6. Huang FM, Chang YC. Cytotoxicity of resin-based restorative materials on human pulp cell cultures. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2002;94(3):361-365. 
7. Gandolfi MG, Siboni F, Prati C. Chemical-physical properties of TheraCal, a novel light-curable MTA-like material for pulp capping. Int Endod J. 2012;45(6):571-579. https://doi.org/10.1111/j.1365-2591.2012.02013.x 
8. Arandi NZ. Calcium hydroxide liners: a literature review. Clin Cosmet Investig Dent. 2017;9:67-72. https://doi.org/10.2147/CCIDE.S141381 
9. Chang HH, Guo MK, Kasten FH, et al. Stimulation of glutathione depletion, ROS production and cell cycle arrest of dental pulp cells and gingival epithelial cells by HEMA. Biomaterials. 2005;26(7):745-753. https://dc.etsu.edu/etsu-works/18426 
10. Kamitakahara M, Kawashita M, Kokubo T, Nakamura T. Effect of polyacrylic acid on the apatite formation of a bioactive ceramic in a simulated body fluid: fundamental examination of the possibility of obtaining bioactive glass-ionomer cements for orthopaedic use. Biomaterials. 2001;22(23):3191-3196. https://doi.org/10.1016/S0142-9612(01)00071-0 
11. Cannon M, Gerodias N, Viera A, et al. Primate pulpal healing after exposure and TheraCal application. J Clin Pediatr Dent. 2014;38(4):333-337. https://acervodigital.unesp.br/handle/11449/117677 
12. American Dental Association. Glossary of Dental Clinical Terms: Direct and Indirect Pulp Capping. Available at: www.ada.org/en/publications/cdt/glossary-of-dental-clinical-and-administrative-ter 
13. Okabe T, Sakamoto M, Takeuchi H, Matsushima K. Effects of pH on mineralization ability of human dental pulp cells. J Endod. 2006;32(3):198-201. 
14. The Dental Advisor. TheraCal LC three-year clinical performance report. 2015. https://dentaladvisor.com/evaluations/theracal-lc-3-yr 
15. Argueta-Figueroa L, Jurado CA, Torres-Rosas R, Bautista-Hernández MA, Alhotan A, Nurrohman H. Clinical efficacy of biomimetic bioactive biomaterials for dental pulp capping: a systematic review and meta-analysis. Biomimetics. 2022;7(4):211. https://doi.org/10.3390/biomimetics7040211 

*BISCO has, on file, calcium release and solubility data for TheraCal LC. 

• THERA Calcium Releasing