Bridging the mechanical cleaning gap

This article examines why mechanical cleaning is not always sufficient to achieve and maintain a satisfactory level of oral health, and what kind of adjunct may help such patients to accomplish better outcomes.

The most recent Adult Dental Health Survey (2009) reports that 66% of participants had visible plaque, despite 75% of dentate adults surveyed claiming to brush their teeth at least twice a day and 25% of those reporting they also floss daily.1

This suggests that there is a gap in at-home oral health care, but why might that be? After all, we know that twice-daily brushing and interdental cleaning are essential in achieving and maintaining oral hygiene,2 as they displace and dislodge plaque bacteria from the tooth surface.3

However, for a number of reasons, brushing and interdental cleaning are insufficient for the majority of the population to control plaque bioflim.2 Illustrating this shortfall, Barnett (2006) wrote: ‘[…] a study of the effectiveness of a powered toothbrush […] revealed plaque reductions of only 20 and 31 percent after one and three minutes of brushing, respectively. In addition, surveys conducted in developed countries reveal the percentage of people who claim to use dental floss or some other interdental cleaning device daily to be between 11 and 51 percent, providing additional evidence for a lack of adequate plaque control.’3

Going on to reflect upon what might help to bridge this gap, Barnett considered the rationale for incorporating an effective antimicrobial mouthrinse in order to help to control plaque biofilm, writing: ‘There is a twofold rationale for daily use of antimicrobial mouthrinses: first, given the inadequacy of mechanical plaque control by the majority of people, as a component added to oral hygiene regimens for the control and prevention of periodontal diseases; second, as a method of delivering antimicrobial agents to mucosal sites throughout the mouth that harbor pathogenic bacteria capable of recolonizing supragingival and subgingival tooth surfaces, thereby providing a complementary mechanism of plaque control.’3

The evidence base

In subsequent years, this topic has been revisited a number of times. In 2014, for instance, Charles and colleagues examined gingival health in the short-term using an essential oil-containing mouthwash on a daily basis.4

They were able to conclude: ‘Significantly more healthy gingival sites and vir­tually plaque free tooth surfaces can be achieved as early as 4 weeks with use of an essential oil antimicrobial mouthrinse compared to mechanical oral hygiene alone. This finding continues through 6 months twice daily use as part of oral care practices compared to mechanical oral hy­giene alone.’4

Also in 2014, following a quantitative assessment of data exploring mouthwash use and the risk of common oral conditions, Boyle and colleagues reported that the evidence supports the use of mouthwash in reducing plaque.5

Going on to explore the differences between various mouthwash formulations, they found that when a mouthwash is used for fewer than three months, those containing chlorhexidine are the most effective of the preparations they considered.5 When used for six months or longer, however, essential oil mouthwashes were shown to equal or exceed the effect of chlorhexidine in controlling plaque as an adjunct to standard care.5 It was also found that mouthwashes containing cetylpyridiniummay be effective, but less so than chlorhexidine and essential oil formulations.5

The authors of the study went on to state: ‘[…] while regular (at least daily) toothbrushing can reduce plaque […], the effect of adjunct flossing appears to be slight if at all. An adjunctive method of plaque control is the use of antiseptics, of which chlorhexidine is the most effective [in studies of less than three months] although its tendency to stain teeth and impair taste makes it generally unacceptable for long-term use.’5

Building on this, in 2015 Chapple and colleagues reported back from Working Group 2 of the 11th European Workshop in Periodontology. The Group reached the conclusion that, ‘[…] where improvements in plaque control are required, adjunctive use of antiplaque chemical agents may be considered. In this scenario, mouth rinses may offer greater efficacy but require an additional action to the mechanical oral hygiene regime.’6

That same year, Araujo and colleagues (2015) published the, ‘[…] first meta-analysis to demonstrate the clinically significant, site-specific benefit of adjunctive EO treatment in people within a 6-month period (that is, between dental visits).’7

They concluded: ‘Addition of daily rinsing with an EO [essential oil] mouthwash to mechanical oral hygiene provided statistically significantly greater odds of having a cleaner […] mouth, which may lead to prevention of disease progression.’7

Just last year, Haas and colleagues (2016) explored the high heterogeneity found in earlier meta-analyses using meta-regression commands, alongside a systematic review to assess randomised clinical trials, testing the efficacy of essential oils as an adjunct to mechanical cleaning in comparison with a placebo or cetylpyridium chloride.8

From this, they were able to conclude: ‘Mouthwashes containing essential oils should be considered the first choice for daily use as adjuvants to self-performed mechanical plaque control.’8

They continued: ‘Expected benefits may be clinically relevant and may also reach the interproximal area.’8

Adjunctive at-home care

All of these findings support the concept that there is a place for using an antimicrobial mouthwash as an adjunct to mechanical cleaning in certain circumstances, offering a considerable advantage, as it, ‘[….] can reach virtually all residual plaque […]’.5

It would seem, therefore, for patients falling short even after brushing and interdental cleaning, certain mouthwash formulations – most notably essential oils and chlorhexidine5 – have the potential to offer an adjunctive benefit.



  1. Adult Dental Health Survey 2009. The Health and Social Care Information Centre 2011
  2. Sharma N et al. Adjunctive benefit of essential oil-containing mouthrinse in reducing plaque and gingivitis in patients who brush and floss regularly: a six-month study. J Am Dent Assoc. 2004; 135: 496-504
  3. Barnett ML. The rationale for the daily use of an antimicrobial mouthrinse. JADA 2006; 137: 16S-21S
  4. Charles CA et al. Early benefits with daily rinsing on gingival health improvements with an essential oil mouthrinse – post–hoc analysis of 5 clinical trials. Journal of Dental Hygiene 2014; 88(Supp): 40-50
  5. Boyle et al. Mouthwash use and the prevention of plaque, gingivitis and caries. Head & Neck Oral Diseases 2014; 20(1): 1-76
  6. Chapple ILC et al. Primary prevention of periodontitis: managing gingivitis. Clin Periodontol 2015; 42 (Suppl. 16): S71-S76
  7. Araujo MWB et al. Meta-analysis of the effect of an essential oil–containing mouthrinse on gingivitis and plaque. JADA 2015; 146(8): 610-622
  8. Haas AN. Essential oils-containing mouthwashes for gingivitis and plaque: Meta-analyses and meta-regression. Journal of Dentistry 2016; 55: 7-15