Mouth care for preventing pneumonia in nursing homes

What is nursing home-acquired pneumonia?

Nursing home-acquired pneumonia (NHAP) is a bacterial infection of the lung occurring in residents of long-term care facilities and nursing homes.

What measures can be taken to prevent nursing home-acquired pneumonia?

People with poor oral hygiene may be more likely to contract an infection. Professional oral care is a combination of brushing teeth and gums, cleaning false teeth, using mouthrinse, and attending check-up visits with a dentist. Usual oral care is self-administered or provided by nursing home staff without special training in oral hygiene.

What did we want to find out?

We wanted to find out whether oral care reduces NHAP. We also wanted to find out whether oral care reduces the number of deaths (from pneumonia and from any cause) among residents of care homes or other long-term care facilities.

What did we do?

We searched scientific databases and trials registers for randomised controlled trials on oral care in residents of care homes. Randomised controlled trials are considered to provide the most reliable scientific evidence because participants are randomly assigned to their treatment groups. We compared and summarised the results of the studies and rated our confidence in the evidence, based on factors such as study methods and sizes.

What did we find?

We found six relevant studies, with a total of 6244 participants, who were randomly assigned to professional or usual oral care. Three studies were carried out in Japan, two in the USA, and one in France. Participants were nursing home residents who did not have pneumonia at the beginning of the studies. Some participants had dementia or systemic diseases such as chronic lung diseases, stroke, or heart failure. Usual care varied but was simple, self-administered care with no help from a dental professional or nursing home staff member trained in oral care. No studies compared oral care to no oral care.

From the limited evidence, we could not determine whether professional mouth care was better or worse than usual oral care for preventing pneumonia, death from pneumonia, or death from any cause. However, two studies suggested that professional mouth care may reduce the number of deaths caused by pneumonia after 24 months of observation.

Only one study measured negative side effects of professional oral care, and reported no serious events. The most common non-serious events were damage to the mouth and tooth staining.

What are the limitations of the evidence?

We found only a small number of studies that used varying methods (e.g. how and when results were measured and the type of professional oral care provided). Therefore, we are not confident about our findings, and further research is required.

How up to date is this evidence?

This evidence is up to date to 30 June 2022.

Authors' conclusions: 

Although low-certainty evidence suggests that professional oral care may reduce mortality compared to usual care when measured at 24 months, the effect of professional oral care on preventing NHAP remains largely unclear. Low-certainty evidence was inconclusive about the effects of this intervention on incidence and number of first episodes of NHAP. Due to differences in study design, effect measures, follow-up duration, and composition of the interventions, we cannot determine the optimal oral care protocol from current evidence. 

Future trials will require larger samples, robust methods that ensure low risk of bias, and more practicable interventions for nursing home residents.

Read the full abstract...

Pneumonia in residents of nursing homes can be termed nursing home-acquired pneumonia (NHAP). NHAP is one of the most common infections identified in nursing home residents and has the highest mortality of any infection in this population. NHAP is associated with poor oral hygiene and may be caused by aspiration of oropharyngeal flora into the lung. Oral care measures to remove or disrupt oral plaque might reduce the risk of NHAP. This is the first update of a review published in 2018.


To assess effects of oral care measures for preventing nursing home-acquired pneumonia in residents of nursing homes and other long-term care facilities.

Search strategy: 

An information specialist searched CENTRAL, MEDLINE, Embase, one other database and three trials registers up to 12 May 2022. We also used additional search methods to identify published, unpublished and ongoing studies.

Selection criteria: 

We included randomised controlled trials (RCTs) that evaluated the effects of oral care measures (brushing, swabbing, denture cleaning mouthrinse, or combination) in residents of any age in nursing homes and other long-term care facilities.

Data collection and analysis: 

At least two review authors independently assessed search results, extracted data, and assessed risk of bias in the included studies. We contacted study authors for additional information. We pooled data from studies with similar interventions and outcomes. We reported risk ratios (RRs) for dichotomous outcomes, mean differences (MDs) for continuous outcomes, and hazard ratios (HRs) or incidence rate ratio (IRR) for time-to-event outcomes, using random-effects models.

Main results: 

We included six RCTs (6244 participants), all of which were at high risk of bias. Three studies were carried out in Japan, two in the USA, and one in France. The studies evaluated one comparison: professional oral care versus usual oral care. We did not include the results from one study (834 participants) because it had been stopped at interim analysis. 

Consistent results from five studies, with 5018 participants, provided insufficient evidence of a difference between professional oral care and usual (simple, self-administered) oral care in the incidence of pneumonia. Three studies reported HRs, one reported IRRs, and one reported RRs. Due to the variation in study design and follow-up duration, we decided not to pool the data. We downgraded the certainty of the evidence for this outcome by two levels to low: one level for study limitations (high risk of performance bias), and one level for imprecision.

There was low-certainty evidence from meta-analysis of two individually randomised studies that professional oral care may reduce the risk of pneumonia-associated mortality compared with usual oral care at 24 months' follow-up (RR 0.43, 95% CI 0.25 to 0.76, 454 participants). Another study (2513 participants) reported insufficient evidence of a difference for this outcome at 18 months' follow-up.

Three studies measured all-cause mortality and identified insufficient evidence of a difference between professional and usual oral care at 12 to 30 months' follow-up.

Only one study (834 participants) measured the adverse effects of the interventions. The study identified no serious events and 64 non-serious events, the most common of which were oral cavity disturbances (not defined) and dental staining.

No studies evaluated oral care versus no oral care.