This article explores the role of oral hygiene in infection prevention, highlights key findings from recent research, and provides recommendations for hospital policies.
By Ayesha Khan, MD, MBA
Recent studies have shown that routine toothbrushing can significantly reduce the incidence of hospital-acquired infections such as pneumonia. Hospital-acquired pneumonia (HAP) is a prevalent and severe infection affecting roughly 300,000 people in the U.S. annually, with exceptionally high incidence rates in intensive care units (ICUs). In these settings, between 12-29% of patients contract HAP, with ventilator-associated pneumonia (VAP) accounting for about 90% of these cases. The all-cause mortality rate for VAP is alarmingly high, ranging from 20-50%. However, this figure may underestimate the actual impact, as an additional 60% of affected patients are often transitioned to long-term care or hospice facilities.
Preventive measures, especially effective oral hygiene practices, are essential in reducing the incidence of these life-threatening infections and improving patient outcomes in critical care environments.
Preventing Infections in Hospital Patients
Good oral hygiene is crucial for maintaining overall health, particularly in hospitalized patients with compromised immune systems. The oral cavity is home to a diverse microbiome, which, under normal circumstances, is kept in balance. However, this balance can be disrupted in hospitalized patients, especially those in ICUs, due to antibiotic use, dry mouth, and reduced saliva production. Furthermore, critically ill patients, particularly those on ventilators, cannot maintain oral hygiene, leading to bacterial overgrowth. Impaired swallowing from ventilators increases the likelihood of inhaling bacteria-laden saliva.
Recent studies reveal that consistent toothbrushing is crucial in disrupting oral biofilms and significantly lowering bacterial load, reducing the incidence of HAP.
Insights from JAMA

A systematic review and meta-analysis published in JAMA Internal Medicine in December 2023 examined the association between daily toothbrushing and HAP. A comprehensive pooled analysis involving 2,786 ICU patients, many with oral or nasal intubation, examined the impact of toothbrushing on HAP and VAP. Chlorhexidine mouthwash, a common antiseptic used for oral care in mechanically ventilated patients, was employed in both the toothbrushing and control groups in eleven of the fifteen studies. The remaining studies used alternatives such as plaque-removing toothpaste, saline, povidone-iodine, or purified water.
Chlorhexidine (CHG) has been shown to reduce the risk of VAP from 26% to 18%, highlighting its effectiveness in decreasing infection rates. However, despite its benefits in reducing VAP incidence, there is no conclusive evidence that CHG impacts mortality rates, the duration of mechanical ventilation, or the length of stay in the intensive care unit. The effectiveness of CHG can vary depending on its concentration, which also influences patient outcomes. Higher concentrations of oral CHG have presented mixed results, with some studies indicating potential adverse effects on the oral mucosa, such as lesions, ulcerations, and bleeding. These findings underscore the need to carefully consider CHG concentration in clinical settings to balance its infection control benefits with the risk of oral complications.
Key Findings:
This metanalysis reinforces that consistent oral care is essential for preventing infections and enhancing patient recovery, illustrating the far-reaching benefits of brushing and flossing for everyone. Key findings of the study are:
- Reduced Incidence of HAP: This analysis revealed that patients receiving toothbrushing interventions exhibited a significant 33% lower risk of HAP, primarily driven by a reduction in VAP rates. The mechanical action of toothbrushing is more effective at disrupting dental plaque than antiseptic rinses alone. This relative 32% reduction in VAP incidence translates to one fewer VAP case for every 12 patients treated with toothbrushing, potentially reducing VAP mortality from 20% to 13.6% and preventing approximately 17,000 deaths annually. Although non-ventilator HAP also showed a trend favoring toothbrushing, it did not reach statistical significance, with only five cases reported across both study groups in two of the studies.
- Lower ICU Mortality: The mortality rate in ICUs was 19% lower among patients who practiced daily toothbrushing compared to those who did not.
- Shorter Mechanical Ventilation Duration: Daily toothbrushing was associated with a shorter duration of mechanical ventilation, indicating quicker recovery times.
- Reduced ICU Length of Stay: Patients who engaged in daily toothbrushing spent less time in the ICU (1.78 days) compared to the control group, suggesting better overall health outcomes.
Additional Research
Other studies have corroborated these findings. For example, a randomized trial published in the Journal of Hospital Infection found that patients who received regular oral care, including toothbrushing, had a 41% reduction in the relative risk of death compared to those who did not. Another study published in the American Journal of Critical Care highlighted the benefits of combining toothbrushing with other oral care practices, such as chlorhexidine mouthwash, to reduce infection rates.
Growing evidence also suggests a strong link between oral health and other chronic diseases such as cardiovascular disease and Alzheimer's disease (AD). While HAP and VAP might not alarm most people, poor oral hygiene can lead to chronic periodontal disease, which affects 46% of adults in the United States and is the most common chronic infection. Periodontal disease significantly increases the risk of atherosclerotic cardiovascular disease (ASCVD) by 3.5 times and Alzheimer's disease by 1.7 times. This connection may be due to shared inflammatory pathways, but gram-negative bacteria from periodontitis can also invade the vascular endothelium, causing endothelial dysfunction. These harmful bacteria have been discovered in distant sites within the body, including aortic plaques and the brains of some Alzheimer's patients, suggesting that dental diseases could exacerbate the progression of other chronic conditions.
Impact on Patient Outcomes
To mitigate serious risks, especially in critical patients, they must maintain a routine of brushing their teeth twice daily and flossing regularly. These accessible preventative measures can significantly reduce the build-up of harmful bacterial plaques and tartar, underscoring the importance of prioritizing oral health to support overall wellness.
- Cost Savings: Reducing the incidence of HAP through improved oral hygiene can lead to substantial cost savings for hospitals. Treating pneumonia is expensive, often requiring prolonged antibiotic use, extended ICU stays, and additional medical interventions. By preventing these infections, hospitals can allocate resources more efficiently and reduce the financial burden of healthcare-acquired infections.
- Improved Quality of Life: The benefits for patients are evident. Reduced infection rates mean fewer days spent in the hospital and a quicker return to normal activities. This can improve the quality of life for patients and their families, reducing the emotional and physical toll of extended hospital stays and severe illnesses.
Recommendations for Hospital Policies
Given the compelling evidence supporting the benefits of daily toothbrushing in reducing HAP and mortality, hospitals should consider implementing comprehensive oral hygiene programs. Here are some recommendations:
- Standardize Oral Care Protocols: Hospitals should develop standardized oral care protocols that include daily toothbrushing for all patients, particularly those in ICUs or with compromised immune systems. These protocols should be integrated into routine nursing care and monitored for compliance.
- Training and Education: Healthcare providers, including nurses and dental professionals, should receive training on the importance of oral hygiene and the proper techniques for performing oral care on hospitalized patients. Education programs can help staff understand the link between oral hygiene and infection prevention.
- Patient and Family Engagement: It is essential to engage patients and their families in oral care practices. Educating patients on the importance of oral hygiene and offering tools and resources for maintaining oral health can empower patients to take an active role in their care.
- Regular Audits and Feedback: Hospitals should conduct regular audits to assess compliance with oral care protocols and provide feedback to staff to help identify areas for improvement and ensure that oral hygiene practices are consistently applied.
In Conclusion
The evidence shows that daily toothbrushing in hospitals is a cost-effective intervention significantly reducing hospital-acquired pneumonia and related deaths. By prioritizing oral hygiene, hospitals can improve patient outcomes, reduce healthcare costs, and enhance the quality of care. As research continues to highlight the critical role of oral hygiene in infection prevention, healthcare facilities must embrace these practices and promote awareness.
Author: Ayesha Khan, MD, MBA, is a registered physician, former research fellow, and enthusiastic blogger. With a wide range of articles published in renowned newspapers and scientific journals, she covers topics such as nutrition, wellness, supplements, medical research, and alternative medicine. As Vice President of Social Communications and Strategy at Renaissance, Ayesha brings her expertise and strategic mindset to drive impactful initiatives. Follow her blog for insightful content on healthcare advancements and empower yourself with knowledge.