It’s the epicenter of new products and scientific discussions that elevate—and sometimes change—the way we practice. RDH Under One Roof is a true gathering of the minds, offering discussions amongst our contemporaries about innovations in dental hygiene. This year was no exception.

From new devices and home care products to compelling modern research, RDH Under One Roof provided comprehensive education about innovative modalities hitting the market through the New Product Presentation, and perhaps one of the most talked-about ingredients was zinc.

What we know about zinc

It turns out, zinc is actually a fantastic ingredient in the influence of root-cause dentistry. From a chemistry, microbiology and oral ecology standpoint, zinc stands at the intersection between scientific benefits and patient outcomes.

Most notably, zinc is a critical ingredient entering the scene in discussing true halitosis management. While oral malodor management has previously focused on masking the problem via mints and gums, dentistry has attempted to explore targeting the root cause of halitosis via mouth rinsing.

However, it has since been discovered that mouth rinsing to remove all bacteria only temporarily addresses halitosis symptoms. To fully understand why everyone is talking about zinc, we need to better understand the new data around oral malodor.

The data around oral malodor

Current data indicates that halitosis affects nearly 1 in 3 adults,¹ and more concerningly, a significant portion of these patients are embarrassed to share this issue with their dental hygienist. What’s more: an estimated 80%-90%² of halitosis originates from the mouth whereas 10%-20% of halitosis is a result of systemic complications.

Despite brushing, flossing and mouth rinsing, many patients report persistent halitosis. This suggests that mechanical disruption and antiseptic suppression alone may not fully address the oral conditions that allow halitosis to persist.

The odors associated with halitosis are caused by volatile sulfur compounds (VSCs): a name given to a group of odorous gasses released by bacteria. It is worth noting that these VSCs not only drive odor; they also break down oral epithelium, enabling bacteria to enter periodontal tissues.

A critical concern, particularly for periodontal patients, is the ability of pathogenic bacteria to break through the epithelium and enter the underlying connective tissue, thus causing the clinical signs of inflammation.

Put simply: while oral malodor is a cosmetic concern for a significant portion of our patients, it also indicates the presence of gasses capable of enhancing the display of periodontal conditions.

Not all odors are created equal

There are three key VSCs that are commonly identified and tested, and the type of gas often indicates the origin of disease.

Hydrogen sulfide (H₂S): Often associated with tongue dorsum biofilm, hydrogen sulfide is produced by bacteria like P. gingivalis and Prevotella. H₂S is linked to early-stage halitosis and gingival inflammation and is responsible for the odor of “rotten eggs.”

Methyl mercaptan (CH₃SH): Correlating with deep periodontal pockets, methyl mercaptan is pathogenic in nature. It is associated with tissue permeability and collagen degradation and is responsible for a “horse” or “barnyard” odor.

Dimethyl sulfide (CH₃)₂S: Linked to extraoral halitosis and systemic sources, the presence of dimethyl sulfide can indicate a bloodborne halitosis, as observed in hepatic and GI disturbances. It is responsible for fishy-cabbage odor.

Halitosis is a byproduct issue

Understanding the role of VSCs in halitosis now means that management of these odors needs to go beyond simply reducing bacteria and focus on reducing the byproducts of these bacteria. Halitosis is a microbiome and chemistry issue, and therefore, products designed to solve bacterial imbalance, and the metabolic byproducts of these bacteria are shifting oral malodor management from “masking” to “neutralizing.”

How zinc entered the conversation

For this, we need to hop in the proverbial “magic school bus” back to chemistry class. I promise, I’ll be brief. Do you remember when your high school chemistry teacher taught you about how certain ions have a binding affinity based on positive and negative charges?

Essentially, zinc ions are positively charged little magnets, and sulfur loves binding to zinc—like the head cheerleader and the captain of the football team on prom night, these two love being together.

Once zinc binds to sulfur, the gas becomes more stable, less volatile and much less odorous.³ This chemistry means that zinc acts as an odor sponge, and serves as a terrific neutralizer for VSCs. In fact, zinc has been used in other industries for odor control, including wastewater treatment and personal care deodorants.

OK, we are done with the chemistry. Class dismissed.

Zinc and its broader oral health relevance

Zinc has been included in various oral health-care products; in mouth washes, it is most commonly combined with cetylpyridinium chloride, chlorhexidine, or essential oils. It is also delivered on the tongue as a component of zinc lactate gel, and effectively loosens and neutralizes biofilm and debris on the tongue dorsum. Finally, formulations of zinc are noted in toothpastes such as zinc citrate, zinc chloride, or zinc oxide.

While these formulations have successfully encouraged VSC neutralization, they also contribute to the destruction of health-producing bacteria capable of stabilizing an optimal oral microbiome.

The oral microbiome with zinc

As research continues to emerge around the successes of zinc and its influence on VSCs, the focus now turns to the role an optimal oral microbiome of health-producing bacteria can play on preserving the oral cavity. New to the market are oral probiotics specifically formulated with zinc. While probiotic bacteria such as L. reuteri⁴ have independently demonstrated a beneficial effect on oral malodor, now combined with zinc, these probiotics provide a terrific solution for patients presenting with halitosis driven by pathogenic bacteria.

Offering root cause solutions

While bopping from session to session at RDH Under One Roof, I marveled at the critical discussions our peers are having around the role of clinical hygienists in addressing the root cause of disease. Root cause dentistry allows us to move from “teeth cleaners” to comprehensive oral health-care practitioners, positioning dental hygienists as a critical member of the health-care team. This fresh take on our role is trending, reminding us that halitosis isn’t just a smell; it’s key microbiology that you can detect. 

Additional reading: Tongue hygiene: Are you missing this critical third step?

Editor's note: This article appeared in the July 2026 print edition of RDH magazine. Dental hygienists in North America are eligible for a complimentary print subscription. Sign up here.

References

1. Silva MF, Leite FRM, Ferreira LB, et al. Estimated prevalence of halitosis: a systematic review and meta-regression analysis. Clin Oral Investig. 2018;22(1):47-55. doi:10.1007/s00784-017-2164-5
2. Rösing CK, Loesche W. Halitosis: an overview of epidemiology, etiology and clinical management. Braz Oral Res. 2011;25(5):466-71. doi: 10.1590/s1806-83242011000500015
3. Young A, Jonski G, Rölla G. Combined effect of zinc ions and cationic antibacterial agents on intraoral volatile sulphur compounds (VSC). Int Dent J. 2003;53(4):237-242.
   doi:10.1111/j.1875-595x.2003.tb00751.x
4. Keller MK, Bardow A, Jensdottir T, Lykkeaa J, Twetman S. Effect of chewing gums containing the probiotic bacterium Lactobacillus reuteri on oral malodour. Acta Odontol Scand. 2012;70(3):246-250. doi: 10.3109/00016357.2011.640281