Review question
How effective are home-use interdental cleaning devices, plus toothbrushing, compared with toothbrushing only or use of another device, for preventing and controlling periodontal (gum) diseases (gingivitis and periodontitis), tooth decay (dental caries) and plaque?
Background
Tooth decay and gum diseases affect most people. They can cause pain, difficulties with eating and speaking, low self-esteem, and, in extreme cases, may lead to tooth loss and the need for surgery. The cost to health services of treating these diseases is very high.
As dental plaque (a layer of bacteria in an organic matrix that forms on the teeth) is the root cause, it is important to remove plaque from teeth on a regular basis. While many people routinely brush their teeth to remove plaque up to the gum line, it is difficult for toothbrushes to reach into areas between teeth ('interdental'), so interdental cleaning is often recommended as an extra step in personal oral hygiene routines. Different tools can be used to clean interdentally, such as dental floss, interdental brushes, tooth cleaning sticks, and water pressure devices known as oral irrigators.
Study characteristics
Review authors working with Cochrane Oral Health searched for studies up to 16 January 2019. We identified 35 studies (3929 adult participants). Participants knew that they were in an experiment, which might have affected their teeth cleaning or eating behaviour. Some studies had other problems that might make their findings less reliable, such as people dropping out of the study or not using the assigned device.
Studies evaluated the following devices plus toothbrushing compared to toothbrushing only: floss (15 studies), interdental brushes (2 studies), wooden cleaning sticks (2 studies), rubber/elastomeric cleaning sticks (2 studies) and oral irrigators (5 studies). Four devices were compared with floss: interdental brushes (9 studies), wooden cleaning sticks (3 studies), rubber/elastomeric cleaning sticks (9 studies), oral irrigators (2 studies). Three studies compared rubber/elastomeric cleaning sticks with interdental brushes.
No studies evaluated decay, and few evaluated severe gum disease. Outcomes were measured at short (one month to six weeks) and medium term (three and six months).
Key results
We found that using floss, in addition to toothbrushing, may reduce gingivitis in the short and medium term. It is unclear if it reduces plaque.
Using an interdental brush, in addition to a toothbrush, may reduce gingivitis and plaque in the short term.
Using wooden tooth cleaning sticks may be better than toothbrushing only for reducing gingivitis (measured by bleeding sites) but not plaque in the medium term (only 24 participants).
Using a tooth cleaning stick made of rubber or an elastomer may be better than toothbrushing only for reducing plaque but not gingivitis in the short term (only 30 participants).
Toothbrushing plus oral irrigation (water pressure) may reduce gingivitis in the short term, but there was no evidence for this in the medium term. There was no evidence of a difference in plaque.
Interdental brushes may be better than flossing for gingivitis at one and three months. The evidence for plaque is inconsistent. There was no evidence of a difference between the devices for periodontitis measured by probing pocket depth.
There is some evidence that oral irrigation may be better than flossing for reducing gingivitis (but not plaque) in the short term.
The available evidence for interdental cleaning sticks did not show them to be better or worse than floss or interdental brushes for controlling gingivitis or plaque.
The studies that measured 'adverse events' found no serious effects and no evidence of differences between study groups in minor effects such as gum irritation.
Certainty of the evidence
The evidence is low to very low-certainty. The effects observed may not be clinically important. Studies measured outcomes mostly in the short term and many participants had a low level of gum disease at the beginning of the studies.
Future research
Future studies should use the new periodontal diseases classification to describe the gum health of participants, and they should last long enough to measure periodontitis and tooth decay.
Using floss or interdental brushes in addition to toothbrushing may reduce gingivitis or plaque, or both, more than toothbrushing alone. Interdental brushes may be more effective than floss. Available evidence for tooth cleaning sticks and oral irrigators is limited and inconsistent. Outcomes were mostly measured in the short term and participants in most studies had a low level of baseline gingival inflammation. Overall, the evidence was low to very low-certainty, and the effect sizes observed may not be clinically important. Future trials should report participant periodontal status according to the new periodontal diseases classification, and last long enough to measure interproximal caries and periodontitis.
Dental caries (tooth decay) and periodontal diseases (gingivitis and periodontitis) affect the majority of people worldwide, and treatment costs place a significant burden on health services. Decay and gum disease can cause pain, eating and speaking difficulties, low self-esteem, and even tooth loss and the need for surgery. As dental plaque is the primary cause, self-administered daily mechanical disruption and removal of plaque is important for oral health. Toothbrushing can remove supragingival plaque on the facial and lingual/palatal surfaces, but special devices (such as floss, brushes, sticks, and irrigators) are often recommended to reach into the interdental area.
To evaluate the effectiveness of interdental cleaning devices used at home, in addition to toothbrushing, compared with toothbrushing alone, for preventing and controlling periodontal diseases, caries, and plaque. A secondary objective was to compare different interdental cleaning devices with each other.
Cochrane Oral Health’s Information Specialist searched: Cochrane Oral Health’s Trials Register (to 16 January 2019), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2018, Issue 12), MEDLINE Ovid (1946 to 16 January 2019), Embase Ovid (1980 to 16 January 2019) and CINAHL EBSCO (1937 to 16 January 2019). The US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication.
Randomised controlled trials (RCTs) that compared toothbrushing and a home-use interdental cleaning device versus toothbrushing alone or with another device (minimum duration four weeks).
At least two review authors independently screened searches, selected studies, extracted data, assessed studies' risk of bias, and assessed evidence certainty as high, moderate, low or very low, according to GRADE. We extracted indices measured on interproximal surfaces, where possible. We conducted random-effects meta-analyses, using mean differences (MDs) or standardised mean differences (SMDs).
We included 35 RCTs (3929 randomised adult participants). Studies were at high risk of performance bias as blinding of participants was not possible. Only two studies were otherwise at low risk of bias. Many participants had a low level of baseline gingival inflammation.
Studies evaluated the following devices plus toothbrushing versus toothbrushing: floss (15 trials), interdental brushes (2 trials), wooden cleaning sticks (2 trials), rubber/elastomeric cleaning sticks (2 trials), oral irrigators (5 trials). Four devices were compared with floss: interdental brushes (9 trials), wooden cleaning sticks (3 trials), rubber/elastomeric cleaning sticks (9 trials) and oral irrigators (2 trials). Another comparison was rubber/elastomeric cleaning sticks versus interdental brushes (3 trials).
No trials assessed interproximal caries, and most did not assess periodontitis. Gingivitis was measured by indices (most commonly, Löe-Silness, 0 to 3 scale) and by proportion of bleeding sites. Plaque was measured by indices, most often Quigley-Hein (0 to 5).
Primary objective: comparisons against toothbrushing alone
Low-certainty evidence suggested that flossing, in addition to toothbrushing, may reduce gingivitis (measured by gingival index (GI)) at one month (SMD -0.58, 95% confidence interval (CI) -1.12 to -0.04; 8 trials, 585 participants), three months or six months. The results for proportion of bleeding sites and plaque were inconsistent (very low-certainty evidence).
Very low-certainty evidence suggested that using an interdental brush, plus toothbrushing, may reduce gingivitis (measured by GI) at one month (MD -0.53, 95% CI -0.83 to -0.23; 1 trial, 62 participants), though there was no clear difference in bleeding sites (MD -0.05, 95% CI -0.13 to 0.03; 1 trial, 31 participants). Low-certainty evidence suggested interdental brushes may reduce plaque more than toothbrushing alone (SMD -1.07, 95% CI -1.51 to -0.63; 2 trials, 93 participants).
Very low-certainty evidence suggested that using wooden cleaning sticks, plus toothbrushing, may reduce bleeding sites at three months (MD -0.25, 95% CI -0.37 to -0.13; 1 trial, 24 participants), but not plaque (MD -0.03, 95% CI -0.13 to 0.07).
Very low-certainty evidence suggested that using rubber/elastomeric interdental cleaning sticks, plus toothbrushing, may reduce plaque at one month (MD -0.22, 95% CI -0.41 to -0.03), but this was not found for gingivitis (GI MD -0.01, 95% CI -0.19 to 0.21; 1 trial, 12 participants; bleeding MD 0.07, 95% CI -0.15 to 0.01; 1 trial, 30 participants).
Very-low certainty evidence suggested oral irrigators may reduce gingivitis measured by GI at one month (SMD -0.48, 95% CI -0.89 to -0.06; 4 trials, 380 participants), but not at three or six months. Low-certainty evidence suggested that oral irrigators did not reduce bleeding sites at one month (MD -0.00, 95% CI -0.07 to 0.06; 2 trials, 126 participants) or three months, or plaque at one month (SMD -0.16, 95% CI -0.41 to 0.10; 3 trials, 235 participants), three months or six months, more than toothbrushing alone.
Secondary objective: comparisons between devices
Low-certainty evidence suggested interdental brushes may reduce gingivitis more than floss at one and three months, but did not show a difference for periodontitis measured by probing pocket depth. Evidence for plaque was inconsistent.
Low- to very low-certainty evidence suggested oral irrigation may reduce gingivitis at one month compared to flossing, but very low-certainty evidence did not suggest a difference between devices for plaque.
Very low-certainty evidence for interdental brushes or flossing versus interdental cleaning sticks did not demonstrate superiority of either intervention.
Adverse events
Studies that measured adverse events found no severe events caused by devices, and no evidence of differences between study groups in minor effects such as gingival irritation.