Baking soda dentifrices and oral health

Abstract

This supplement to The Journal of the American Dental Association (JADA) is a compilation of a number of reports based on research of the effects of sodium bicarbonate (baking soda) as a dentifrice ingredient. This supplement provides information of value to dental practitioners on the benefits of baking soda dentifrices on oral health. The authors chosen to develop this supplement of JADA were selected because of their expertise in the topics included in this issue and their involvement in dental research both clinically as well as in the laboratory. As dental professionals, we are aware that the removal and prevention of supragingival bacterial plaque by good oral hygiene is necessary to achieve and maintain oral health from both a caries and periodontal perspective. In addition to prevention of caries and periodontal disease, a dentifrice may serve as a delivery system for agents to reduce tooth sensitivity as well as for esthetic benefits. However, we also realize that although a dentifrice may have a variety of benefits, patient compliance primarily is affected not only by the health benefits but also the taste. The impact of taste on patients’ oral hygiene was demonstrated in a study in which 1 group of college students was given a mixture of baking soda and salt to brush with, another group was given water only to brush with, and a third group was given a well-flavored dentifrice.1Dudding N.J. Dahl L.O. Muhler J.C. Patient reactions to brushing teeth with water, dentifrice, or salt and soda.J Periodontol. 1960; 31: 386-392Crossref Google Scholar In this study, plaque was measured as an indicator of oral hygiene, and the highest plaque scores were recorded in the no dentifrice group. Dropout rates were 20% in the unflavored mixture group, 46% in the water group, and only 5% in the well-flavored dentifrice group. Since taste is important for compliance with brushing, current dentifrices on the market have successfully masked the taste of baking soda by the judicious use of flavoring and sweetening agents. The role of flavoring for patient compliance is discussed in an article by Newbrun2Newbrun E. The use of sodium bicarbonate in oral hygiene products and practice.Compend Contin Educ Dent Suppl. 1997; 18: S2-S7PubMed Google Scholar in which he states that dentifrices containing baking soda (sodium bicarbonate) are widely used and have been shown to motivate patients to improve their oral hygiene. Although modern research methods on dentifrices containing baking soda did not begin until the 1970s, in 1911 an article in a leading dental journal described “the ideal tooth powder” as being “capable of giving a high polishing to the teeth but without the danger of scratching them in the least. It must, in addition, have a stringent stimulant, actively cleansing, antiseptic and alkaline properties, just enough to be helpful to the gums without any danger of irritating them.”3Sarrazin J.J. How to clean the mouth: thread, brushes, powders, washes and paste.Oral Hyg J Dent. 1911; 1: 827-848Google Scholar As you will see from the articles in this supplement, this is almost a perfect description of our modern-day baking soda dentifrices and the advantages that they have to offer. In fact, the author of the 1911 article went on to recommend baking soda as one of the ingredients that should be in this ideal tooth powder.3Sarrazin J.J. How to clean the mouth: thread, brushes, powders, washes and paste.Oral Hyg J Dent. 1911; 1: 827-848Google Scholar In 1974, Colgate introduced a dentifrice containing baking soda and, in the early 1980s, the Church & Dwight Company began the development of a baking soda–containing dentifrice, which, although it contained 94% baking soda, had a taste that was pleasing to the public. It was first sold in 1986 regionally and, in 1988, was sold nationally.4Ciullo P.A. Saleratus. Maradia Press, Naugatuck, CT1994: 182-184Google Scholar Soon other manufacturers introduced new baking soda toothpastes, including Colgate Palmolive, Procter & Gamble, and Unilever. Concentrations of baking soda in the various dentifrices on the market at that time ranged from 5% to 94%. Currently, the major producer of baking soda dentifrices in the United States is the Church & Dwight Company, sponsors of this supplement to JADA. It is noteworthy that most baking soda–based dentifrices contain fluoride, which is compatible with baking soda. The articles selected for inclusion in this supplement were based on the safety and efficacy of baking soda–containing dentifrices for a variety of uses. Safety issues of concern to clinicians include effects on enamel and dentin, the oral microflora, oral soft tissues including gingival health, and remineralization and demineralization. In reviewing the various articles in this issue, I noted that a significant amount of research data have been generated over the years regarding the safety and efficacy of baking soda–containing dentifrices. Some of the highlights of the research findings discussed in this supplement are summarized below. The abrasivity of a dentifrice on the tooth depends on a number of factors, including the inherent hardness of the abrasive ingredient, its particle size and shape, the pH of the dentifrice, the overall formulation, and factors unrelated to the dentifrice per se, such as the frequency of brushing, the hardness of the toothbrush bristles, and the pressure applied.5Newbrun E. Dentifrices.in: Cariology. 3rd ed. Quintessence, Chicago, IL1989: 295-313Google Scholar The intrinsic hardness of baking soda is relatively low, of the same magnitude as dentin itself, and less than that of enamel or of other commonly used dentifrice abrasives, such as calcium carbonate, anhydrous dicalcium phosphate, and calcium pyrophosphate.6Lehne R.K. Winston A.E. Abrasivity of sodium bicarbonate.Clin Prev Dent. 1983; 5: 17-18PubMed Google Scholar Therefore, the use of a baking soda dentifrice provides a measure of safety to enamel and dentin in spite of the “vigor” patients may use while brushing their teeth. The low abrasivity of baking soda dentifrices makes them especially suited for safe daily use in oral hygiene regimens.7Hara A.T. Turssi C.P. Baking soda as abrasive in toothpastes: mechanism of action and safety and effectiveness considerations.JADA. 2017; 148: 27S-33SGoogle Scholar Neutralization of plaque acids by baking soda is anticariogenic by facilitating remineralization of incipient carious lesions. Patients in the fasting state have plaque that is normally supersaturated with respect to the tooth mineral,8Margolis H.C. Moreno E.C. Composition and cariogenic potential of dental plaque fluid.Crit Rev Oral Biol Med. 1994; 5: 1-25Crossref PubMed Scopus (71) Google Scholar which means that mineral tends to precipitate out of the fluid, and the teeth have no tendency to dissolve. At the so-called critical pH of approximately 5.1 to 5.5, the plaque fluid is barely saturated with respect to tooth mineral (that is, teeth do not dissolve, and mineral does not tend to precipitate out). However, if the pH of the plaque falls below the critical pH, the plaque fluid becomes unsaturated, and the teeth begin to dissolve, which initiates dental caries. When the pH returns above the critical pH, an early caries lesion will tend to remineralize, particularly in the presence of fluoride, which is included in most baking soda–containing dentifrices.9Zero D.T. Evidence for biofilm acid neutralization by baking soda.JADA. 2017; 148: 10S-14SGoogle Scholar Baking soda has been shown to be efficacious in reducing the acidity of plaque fluid. Therefore, its impact on oral remineralization and demineralization is significant. Dawes10Dawes C. Effect of a bicarbonate-containing dentifrice on pH changes in a gel stabilized plaque after exposure to sucrose.Compend Contin Educ Dent Suppl. 1996; 17: S8-S10PubMed Google Scholar reported that simulation of the use of a high-bicarbonate dentifrice at a time when plaque pH had fallen to about 4.5 caused a rapid return of the pH toward neutrality, whereas simulation of the use of a low-bicarbonate dentifrice had much less effect. Microbiological studies have shown that baking soda solutions have significant bactericidal activity against oral pathogens.11Sabharwal A. Scannapieco F.A. Baking soda dentifrice and periodontal health: a review of the literature.JADA. 2017; 148: 15S-19SGoogle Scholar Concentrated solutions of baking soda suspensions from periodontal pockets have been shown to rapidly immobilize oral spirochetes and motile rods obtained in mixed pockets and viewed in wet mounts under phase contrast microscopy.12Rams T.E. Keyes P.H. Jenson A.B. Morphological effects of inorganic salts, chloramine-T, and citric acid on subgingival plaque bacteria.Quintessence Int Dent Dig. 1984; 15: 835-844PubMed Google Scholar Subsequent in vitro studies using pure cultures of putative periodontal pathogens established the minimal bactericidal concentration of baking soda13Newbrun E. Hoover C.I. Ryder M.I. Bacteriocidal action of bicarbonate ion on selected periodontal pathogenic microorganisms.J Periodontol. 1984; 55: 658-667Crossref PubMed Scopus (33) Google Scholar and of baking soda–hydrogen peroxide, which exhibited synergistic activity.14Mikyasaki K.T. Genco R.J. Wilson M.E. Antimicrobial properties of hydrogen peroxide and sodium bicarbonate individually and in combination against selected oral, gram-negative, facultative bacteria.J Dent Res. 1986; 65: 1142-1148Crossref PubMed Scopus (51) Google Scholar Periodontal pathogens were more susceptible to baking soda than were organisms representative of soil, skin, and fecal flora. These findings help one to understand the basis for the reduction of plaque and improvement of the health of oral tissues that researchers have reported in clinical studies in which they found plaque reduction and improvement in periodontal health in patients who used a baking soda–containing dentifrice.15Barnes C.M. An evidence based review of sodium bicarbonate as a dentifrice agent.Compend Contin Educ Dent Suppl. 1999; 6: 3-11Google Scholar, 16Myneni S.R. Effect of baking soda in dentifrices on plaque removal.JADA. 2017; 148: 4S-9SGoogle Scholar Researchers in a number of studies have reported that, in spite of its low abrasivity, dentifrices containing baking soda are more effective in stain removal and whitening than some non–baking soda—containing dentifrices with a higher abrasivity.17Li Y. Stain removal and whitening by baking soda dentifrice: a review of literature.JADA. 2017; 148: 20S-26SGoogle Scholar In view of the current interest by patients in tooth whitening, this feature may improve patients' compliance with oral hygiene. Also, for patients whose oral condition benefits from the use of chlorhexidine mouthrinses, the offensive stain caused by chlorhexidine has been shown to be reduced by the use of baking soda–containing dentifrices. In clinical gingivitis studies, researchers evaluate inflammation as measured by bleeding points and gingival health as measured by a gingival index and plaque reduction. The US Food and Drug Administration and the American Dental Association have published helpful guidelines on study design and results interpretation. Beneficial effects of baking soda on gingival health have been found by researchers in 3- to 6-month clinical studies of baking soda–containing dentifrices as compared with placebos.11Sabharwal A. Scannapieco F.A. Baking soda dentifrice and periodontal health: a review of the literature.JADA. 2017; 148: 15S-19SGoogle Scholar, 18Zambon J.J. Mather M.L. Gonzales Y.A. Microbiological and clinical study of the safety and efficacy of baking soda dentifrices.Compen Contin Educ Dent Suppl. 1996; 17: S39-S44PubMed Google Scholar However, clinical data have shown variable results because of variation across studies in baking soda formulations, study duration, and choice of controls. The beneficial effect of baking soda in gingival health is anticipated in view of its antibacterial and biofilm-disruptive activity. Additional clinical studies would be useful to confirm the role of baking soda on gingival health. The safety of dentifrices containing baking soda has been extensively studied.15Barnes C.M. An evidence based review of sodium bicarbonate as a dentifrice agent.Compend Contin Educ Dent Suppl. 1999; 6: 3-11Google Scholar, 18Zambon J.J. Mather M.L. Gonzales Y.A. Microbiological and clinical study of the safety and efficacy of baking soda dentifrices.Compen Contin Educ Dent Suppl. 1996; 17: S39-S44PubMed Google Scholar, 19Kashket S. Yaskell T. Effects of a high bicarbonate dentifrice on intraoral demineralization.Compend Contin Educ Dent Suppl. 1996; 17: S11-S16PubMed Google Scholar Researchers in both clinical and laboratory studies have found these products to be safe, to be low in abrasiveness, to not contribute to root sensitivity, and to be safe for use by patients on low-salt diets. This latter finding is important, given that patients swallow 5% to 7% of a dentifrice with which they brush.20Hall B. Tozer S. Safford B. Coroama M. et al.European consumer exposure to cosmetic products, a framework for conducting population exposure assessments.Food Chem Toxicol. 2007; 45: 2097-2108Crossref PubMed Scopus (118) Google Scholar In reviewing the evidence presented in this supplement of JADA, the following summary statements are in order:⁃The low abrasivity of dentifrices containing baking soda makes them especially suited for safe daily use in oral hygiene regimens.⁃Microbiological studies have shown that baking soda products have significant bactericidal activity against oral pathogens, which explains benefits demonstrated in clinical studies on plaque biofilm and gingivitis reduction.⁃Baking soda dentifrices favor patient compliance because they have stain-reducing and whitening properties, a feature which motivates patients to brush as instructed by their oral care practitioner.⁃Neutralization of plaque acids by baking soda supports caries reduction as well as facilitation of remineralization of incipient carious lesions.