Can Wasabi-Derived Hexaraphane Regenerate Dentin in Sensitive Teeth? A Novel TRPA1-Independent Mechanism

The sharp, sudden pain that shoots through a tooth the moment you sip a cold drink or bite into ice cream—many people recognize this sensation even when there is no cavity. Behind these "sensitive teeth" lies the regeneration of dentin, a process that a compound this site has featured many times may help support: hexaraphane (6-MSITC; 6-methylsulfinylhexyl isothiocyanate), derived from Japanese wasabi. ¹

The study featured here was published in 2026 in The Journal of Physiology by Professor Yoshiyuki Shibukawa and colleagues at Tokyo Dental College. It showed that hexaraphane may act on odontoblasts—the cells that build teeth—to support dentin regeneration (the formation of reactionary dentin). Notably, this effect did not depend on TRPA1, the sensor best known for detecting the pungency of wasabi; instead, it worked through a newly identified mechanism. ¹

What You Will Learn

• Why "dentin pain," the sensitivity to cold, occurs
• The unexpected relationship between the wasabi pungency sensor TRPA1 and odontoblasts, the cells that build teeth
• The key points of how hexaraphane (6-MSITC) supported dentin regeneration
• That this effect worked through a novel ion-transport mechanism independent of TRPA1

Background: Why Do Teeth Feel Sensitive? Dentin and Odontoblasts

First, let us clarify what causes this sharp pain. A tooth has a layered structure: the very hard enamel on the outside, the slightly softer dentin※ beneath it, and the dental pulp※ at the center, where nerves and blood vessels gather.

Dentin

The main inner layer of the tooth, beneath the enamel. It is threaded with countless fine channels (dentinal tubules).

Dental pulp

The tissue inside the dentin, where nerves and blood vessels gather.

When acidic foods and drinks or overly vigorous brushing wear away the enamel, the dentin underneath becomes exposed. Dentin is threaded with countless tunnel-like fine channels filled with fluid. When a stimulus such as cold is applied, this fluid moves within the channels. Odontoblasts※, the cells that build dentin, are thought to sense this movement and release signaling substances (ATP and glutamate) that transmit a signal to the nerves, producing the sharp, sensitive pain known as dentin pain. ¹

Odontoblast

A cell that produces dentin. Odontoblasts line the outermost layer of the dental pulp.

Dentin pain

A transient, sharp pain that occurs when a stimulus such as cold reaches exposed dentin.

To address such sensitivity, dentistry has widely used approaches such as filling the worn area with resin or coating the dentin surface with a medicated agent. These treatments, however, physically seal the surface and can sometimes come loose. This has drawn recent interest to a different idea: acting directly on odontoblasts to regenerate the dentin itself. The present study sheds light on a candidate compound for that purpose. ¹

Wasabi-Derived Hexaraphane (6-MSITC) and the TRPA1 Sensor

So why wasabi? This is where a sensor protein called TRPA1 comes in. TRPA1 is known as the sensor that detects the pungency of wasabi. ² Research on these TRP channels, which sense temperature and irritants, contributed to the 2021 Nobel Prize in Physiology or Medicine.

TRPA1 is found not only in the nerves of the skin and the lining of the mouth but also in the tooth's odontoblasts, where it had been found to be involved in dentin formation. The research team therefore reasoned that stimulating this sensor with a wasabi compound might prompt odontoblasts to build dentin. ¹

The lead candidate was hexaraphane (6-MSITC), one of the compounds found in Japanese wasabi. Hexaraphane is a compound this site has featured many times. We have previously introduced how it activates the antioxidant master regulator Nrf2 through a dual pathway and a review outlining its potential for cancer, dementia, and obesity. The present study adds a new facet—"dental and dentin regeneration"—to hexaraphane's many faces. ³

The Research Question

Wasabi-derived compounds (wasabi sulfinyl compounds), including hexaraphane, are known to activate TRPA1. Yet it was unclear whether they truly promote mineralization in odontoblasts (that is, the building of dentin), and—if they do—whether that effect is mediated by TRPA1. ¹

The research team therefore prepared hexaraphane and eight of its derivatives and examined, from multiple angles, their effects on odontoblast mineralization and the underlying mechanism. ¹

What the Study Found

1. Hexaraphane Promoted Mineralization in Odontoblasts

When wasabi sulfinyl compounds were added to cultured odontoblasts, hexaraphane (6-MSITC) and one of its derivatives, 6-MSFITC, most strongly promoted mineralization. Mineralization—the deposition of calcium ions and other minerals to form hard tissue—is an essential process for tooth development and regeneration. ¹

2. The pH of the Culture Medium Rose

At the same time, the pH of the culture medium in which the cells were grown rose significantly. This change reflects the ion exchange described below and is considered a clue to the creation of an environment in which mineralization proceeds more readily. ¹

3. Dentin Regeneration Was Promoted in Rat Teeth (In Vivo)

The effect was not confined to the culture dish. When a hole was drilled in the molar (the mandibular first molar) of rats and hexaraphane was applied, the formation of reactionary dentin※ was promoted directly beneath it. This shows that hexaraphane supported dentin regeneration even within the teeth of living animals. ¹

Reactionary dentin

Dentin newly produced from within by a tooth that has been worn down or stimulated. It is a repair response by which the tooth protects itself.

4. AITC, a Pungent Wasabi Compound, Conversely Suppressed Mineralization

The surprising part comes here. For comparison, the team also tested AITC (allyl isothiocyanate), a representative pungent compound of wasabi that is known to activate TRPA1. Yet, far from promoting mineralization, AITC significantly suppressed it. ¹ From this result, the team concluded that hexaraphane's promotion of mineralization is likely due to a mechanism that does not go through—that is, is independent of—TRPA1 activation. ¹ It should be noted, however, that this is an inference drawn from the fact that a TRPA1 agonist acted in the opposite direction, rather than from directly blocking TRPA1 itself to confirm it. Put another way, this also means that not just any pungent wasabi compound will do.

5. The Underlying Mechanism Was a System That "Carries Calcium Out"

So what was the mechanism? The key lay in the odontoblasts' ability to carry calcium out of the cell. Dentin is built up as calcium sent outside the cell accumulates. In other words, the more active this "carrying out" becomes, the more readily new dentin is formed. ¹

The team found that hexaraphane accelerated this export by linking several "carrier proteins" built into the cell in a relay, like a bucket brigade. When the proteins along this pathway (CA and PMCA) were blocked with drugs, mineralization scarcely progressed even when hexaraphane was added. This series of mechanisms (the CA–SLC4As–NHE–NCX–PMCA axis) is considered to be the true basis for how hexaraphane promotes dentin regeneration. The earlier observation that "the pH of the culture medium rose" is also thought to reflect the ion exchange occurring at the entrance to this relay. ¹

For those who wish to know the detailed flow of how ions are passed along inside the cell, please see the figure below.

The Significance of This Study: From "Drill and Cover" to "Regenerate"

The significance of this study lies in demonstrating, at the molecular level, the potential to broaden the response to sensitive teeth—from the conventional approach of physically sealing the worn surface to an approach that acts on odontoblasts to regenerate the dentin itself. It is also intriguing that the agent responsible was a compound found in familiar Japanese wasabi. ¹ At the end of the paper, the team states that they have already begun a clinical study to use hexaraphane as a dentin regeneration therapy. ¹ However, those results had not been published at the time of the paper, and the evaluation of efficacy and safety in humans awaits future reports.

Limitations and Future Challenges

At the same time, this study has several limitations. It centers on experiments using cultured cells and rats, and whether the same effect can be obtained in humans must await verification by future clinical studies. ¹

Furthermore, hexaraphane's effect has been reported to change direction depending on concentration. Mineralization was promoted in the 40 µM and 100 µM range, whereas at the lower concentrations of 4–20 µM, mineralization conversely decreased. At 10 µM and 50 µM, the number of cultured cells themselves also decreased significantly. The paper describes this as a "bimodal" effect and states that its detailed mechanism is currently unknown. ¹

Even so, the discovery of a clue leading from a familiar food compound toward dental regenerative medicine is a finding that suggests how far future research may extend.

Summary

• "Dentin pain," the sensitivity to cold, is thought to arise when fluid moves within the channels of exposed dentin and a signal is transmitted to the nerves via odontoblasts
• Japanese wasabi–derived hexaraphane (6-MSITC) promoted mineralization in cultured odontoblasts and raised the pH of the culture medium
• In rat teeth, hexaraphane supported the formation of reactionary dentin, showing that it acts on dentin regeneration in vivo as well
• Because AITC, a representative pungent compound of wasabi, conversely suppressed mineralization, hexaraphane's effect is considered independent of TRPA1 and was concluded to arise from a coordinated ion-transport system called the CA–SLC4As–NHE–NCX–PMCA axis
• Hexaraphane's effect changes direction depending on concentration, and at low concentrations mineralization conversely decreased; the paper describes this bimodal mechanism as "unknown"
• At present, however, the work centers on cells and rats, and efficacy and safety in humans await future verification

References

1. Furusawa Y, et al. 6-Methylsulfinylhexyl isothiocyanate activates carbonic anhydrase-dependent HCO₃⁻/H⁺/Na⁺/Ca²⁺ transport via SLC4As–NHE–NCX–PMCA axis in odontoblasts. The Journal of Physiology. 2026. ↩
2. Jordt SE, et al. Mustard oils and cannabinoids excite sensory nerve fibres through the TRP channel ANKTM1. Nature. 2004;427(6971):260-265. ↩
3. Bartkowiak-Wieczorek J, et al. Methylsulfinyl Hexyl Isothiocyanate (6-MSITC) from Wasabi Is a Promising Candidate for the Treatment of Cancer, Alzheimer's Disease, and Obesity. Nutrients. 2024;16(15):2509. ↩