Original Article

Effects of Mechanical, Chemical and Combination Methods on Halitosis: A Systematic Review and Meta-analysis


  • Maryam Alsadat Hashemipour
  • Ehsan Iranmanesh

Received Date: 12.09.2020 Accepted Date: 12.08.2021 Meandros Med Dent J 2022;23(3):282-290


Halitosis or bad breath is one a problem that can have a profound effect on the quality of life associated with health. The purpose of this systematic review and meta-analysis was to investigate the treatments used to treat halitosis.

Materials and Methods:

This study involved a systematic review and meta-analysis. It was used in conjunction with treatment, management, therapy, and therapeutics for the first-call combination of bad breath, bad breath, halitosis, pseudohalitosis, halitophobia. Finally, these articles were removed according to the text and 37 articles remained.


The effect of chemical methods on the treatment of bad breath was significant; halitosis was reduced by 1.19 [95% confidence interval (CI), 1.57 to 0.78]. Additionally, there was heterogeneity between studies (Q=11.32). Mechanically, despite the presence of heterogeneity between studies (Q=5.41), the p-value was not statistically significant (p=0.15), with the effect of the combined methods, bad breath was reduced to 1.18 (with a 95% CI, 1.68 to -0.51). Additionally, there is heterogeneity (Q=12.14).


The results of this study show that chemical and compound methods are effective in reducing bad breath.

Keywords: Halitosis, bad breath, treatment, management


Bad breath, also referred to as halitosis and oral malodor, is one of the grave problems that many people try to avoid. Under normal conditions, the human breath is odorless and has a distinctive odor called ‘human odor’ (1,2). Approximately, a quarter of the world population have halitosis, with the majority exhibiting this condition occasionally (3). Patients usually do not express the primary complaint; instead, the patients’ family members and relatives become aware of the condition (3,4).

Dental practitioners estimate that only 25% of the population has halitosis, and the remaining 75% only has a medical condition or halitophobia (5). Several treatment modalities have been suggested for the treatment of halitosis; however, there is no consensus yet on a standard protocol for this problem.

Although many studies have been undertaken on halitosis, no systematic review or meta analysis has been published on techniques to evaluate the halitosis and the treatment modalities of halitosis. Therefore, the present systematic review and meta-analysis were undertaken to review the treatment modalities of halitosis during the past 20 years.

Materials and Methods

Combinations of the words halitosis, bad breath, oral odor, pseudohalitosis, and halitophobia with the words treatment, management, therapy, and therapeutics were used for the initial search. The search in databases brought up 1175 records, which were transferred to the Mendeley software. Then, a search based on ‘author’, ‘year’, and ‘title’ revealed 441 repeated records. The approval for the this study was approved by ethical committee of Kerman University of Medical Sciences (approval code: IR.KMU.REC.1397.472.).

Statistical Analysis

At the end of this stage, 737 records remained after the elimination of 441 repeated records. Finally, 37 articles (Table 1), were evaluated (Figure 1).


The effect of chemical techniques on halitosis was statistically significant; i.e., halitosis decreased by 1.19% [at 95% confidence interval (CI): -0.78-1.57]. Also, there was a heterogeneity between the studies (Q=11.325) (Table 2).

Despite the heterogeneity between the studies (Q=5.41), the p-value did not indicate statistical significance (p=0.15) (Table 2).

The effects of combined techniques on the elimination of halitosis were significant; i.e., halitosis decreased by 1.18% (at a 95% CI: -0.51 to -1.68). In addition, there was heterogeneity between the studies (Q=12.142) (Table 3).

All work included initial search of the articles, selection of them, record and interpretation of the articles and meta-analysis was done by two authors of the article.


The results showed that the pharmaceutical techniques are useful in this respect; however, mechanical techniques are useful, too. Also, a combination of chemical and pharmaceutical techniques was found to be effective.

Akkaoui and Enhibi (6) and Buunk-Werkhoven et al. (7) reported the results only based on questionnaires, with no tools for measuring the severity of halitosis, including halitometers and volatile sulfur compounds (VSC) analyses; therefore, they were eliminated. These reports are studies that have a very small sample size (1 to 6) with a specific medical condition or specific manifestations of a medical condition (8-10). These studies are suitable for introducing new diseases but cannot be generalized due to their very small sample size. Therefore, they are not included in systematic reviews. For example, Lopes et al. (9) evaluated the effect of photodynamic therapy with the use of methylene on the oral surfaces in five 14-16 year-old subjects.

Another study whose abstract was available was carried out by Yaegaki and Sanada (11) in 1992 on the effect of olive oil and essential oils on decreasing halitosis in comparison with repeated rinsing of the oral cavity. The researchers concluded that the use of these oils could decrease halitosisby 65% (11).

A study by Rassameemasmaung et al. (12) showed that the use of a herbal extract of G. mangostana might be useful as an adjunct in the treatment of halitosis.

An evaluation of the year of publication showed that 18 studies were published from 2015 on, and 19 articles were published from 2015 to 2018. Of all the studies published after 2015, almost half (nine studies, 24.3% of all the studies) were published in 2016, indicating that the discrepancies in the results of studies on the treatment of halitosis have attracted the attention of researches more than ever.

A study by Porter and Scully (13) showed that the use of mechanical techniques, such as cleaning the surface of the tongue, brushing, use of dental floss, and periodontal treatments, could control the dental plaque and decrease halitosis.

In a study by Chen and Jin (14) 251 articles were included. These researchers showed that the mechanical cleaning of the tongue surface (brushing and scrubbing) significantly decreased halitosis (a decrease in VSC and Winkel tongue coating index, and an improvement in the periodontal status) in the case group. However, there was no significant difference between the case and control groups.

Several studies have shown a relationship between halitosis and periodontitis (15-17). At present, the majority of researchers believe that the two factors above affect each other (18).

Several studies have shown that chlorhexidine (CHX), essential oils, triclosan, cetylpyridinium chloride (CPC), chlorine dioxide, zinc salts, benzalkonium chloride, hydrogen peroxide, and sodium bicarbonate mouthwashes are successful when they are combined with mechanical techniques (19,20).

Studies by Thrane et al. (21), and Thaweboon and Thaweboon (22) showed that mouthwashes such as CHX, CPC, triclosan, essential oils, quaternary ammonium compounds, benzalkonium chloride, and hydrogen peroxide mouthwashes are effective in decreasing halitosis.

CHX has been considered the gold standard for the treatment of halitosis. CHX, in combination with CPC, decreased VSC levels to a great extent and decreased the counts of both aerobic and anaerobic bacteria in three hours. However, patients might not be interested in using CHX for a long time, because it has an unpleasant taste and stains the teeth reversibly (23).

These research works have shown that brushing the tongue with toothpaste could reduce the levels of VSCs for at least 1 h, and this was more effective than only brushing the teeth (24,25).


The results of the present study showed that the chemical and combined techniques are effective in decreasing halitosis.


The authors would like to express their gratitude to the Vice Deputy of Research at Kerman University of Medical Sciences for their financial support (Reg. No. 97000888). The Ethic approval Code is IR.KMU.REC.1397.472.


Ethics Committee Approval: The approval for the this study was approved by ethical committee of Kerman University of Medical Sciences (approval code: IR.KMU.REC.1397.472.).

Informed Consent: This study is a systematic review and meta-analysis.

Peer-review: Externally peer-reviewed.

Authorship Contributions

Concept: M.A.H., Design: M.A.H., Data Collection or Processing: E.I., Analysis or Interpretation: E.I., Literature Search: E.I., Writing: M.A.H.

Conflict of Interest: No conflict of interest was declared by the authors.

Financial Disclosure: Vice Deputy of Research at Kerman University of Medical Sciences for their financial support (Reg. No. 97000888).


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