Chewing Gum Containing Citric Acid Reduces the Burden of Periodontal Pathogens

Hiroki Nikawa*, 1, Sachiyo Igarashi2, Osamu Takasu2, Hideo Tataka2, Fumiki Harano1, Shigeo Shinohara2, 3, Seicho Makihira1, Toshinobu Takemoto1, Takeshi Murayama1, Takahiro Satoda1, Hideaki Amano1, Hidemi Kurihara4
1 Institute of Oral Science, Hiroshima University, Faculty of Dentistry, 1-2-3 Kasumi, Minami-ku Hiroshima, 734-8553 Japan
2 Otsu Laboratory for Skin Care Science, Rejuvenate Division, Otsuka Pharmaceutical Co., Ltd. 3-31-13 Saigawa, Otsu, Shiga, 520-0002 Japan
3 Department of Experimental Radiology, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga, 520-2192, Japan
4 Department of Periodontology & Endodontology, Division of Frontier Medical Science, Graduate School of Biomedi-cal Sciences, Hiroshima University. 1-2-3 Kasumi, Minami-ku Hiroshima, 734-8553 Japan

© 2008 Nikawa et al.;

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Institute of Oral Science,Hiroshima University, Faculty of Dentistry. 1-2-3 Kasumi, Minami-ku Hiroshima, 734-8553 Japan;



In a preliminary study, we noted that citric acid has the potency to induce human beta defensins (hBD-2) in salivary secretions. As hBDs are thought to ameliorate periodontal disease by suppressing key periodontal pathogens we developed a citric acid-containing chewing gum (CA-gum) to test this hypothesis. Here we report, the effect of CA-gum on three major periodontal pathogens Prevotella intermedia (Pi), Tannerella forsythia (Tf), Treponema denticola (Td) and Fusobacterium species (Fb).


A randomized, double-blind, placebo-controlled trial with 61 individuals, was conducted over 14 days. Each subject was allowed to chew CA-gum (31 subjects) or placebo gum (30 subjects) at irregular intervals, but was instructed to eat at least three pieces of gum a day. None had active caries, symptoms of gingivitis or periodontal disease, smoking history, or concurrent medication. To determine the levels of oral carriage of the putative pathogens, saliva was collected from each subject by paraffin chewing in a standard manner and, the number of total cultivative microorganisms (CFUs) determined. Five key periodontal pathogens, Pg, Pi, Tf, Td and Fb present in saliva were determined quantitatively using real-time polymerase chain reaction (PCR) (BML Inc., Saitama, JAPAN).


Compared with the placebo chewing gum group the CA-gum group had significantly lower levels of Prevotella intermedia, Tannerella forsythia, and Fusobacterium spp. in their saliva. (Wilcoxon t-test; p<0.01). However, chewing of either type of gum did not affect the salivary carriage of total cultivative bacteria (Wilcoxon t-test; p>0.05).


Consumption of citric acid-laced chewing gum reduces significantly the burden of periodontal pathogens in saliva.

Keywords: Saliva, beta defensin, periodontal bacteria, citric acid.