Learn about the oral-systemic link and your role in preventive care.

MANY CONSIDER ORAL CARE an element of grooming, not an infection control measure. However, an association exists between poor oral care and systemic disease. For example, aspiration of oropharyngeal pathogens into the lungs can lead to pneumonia. Immobile or confined patients rely on oral care performed by nurses and other caregivers to prevent hospital-acquired pneumonia (HAP), which, according to Kim and colleagues, remains the leading cause of mortality in older adults. Understanding the connection between proper oral care and HAP prevention can help nurses protect patients.

HAP explained

HAP occurs in a patient’s lung parenchyma 48 to 72 hours after initial hospitalization. It’s diagnosed via auscultation, decreased oxygen saturation, shortness of breath, change in cognition, chest x-ray, sputum specimen, laboratory analysis, or bronchoscopy. According to Rope and colleagues, of the older adults who survive HAP, many experience decreased exercise capability, cardiovascular disease, cognitive decline, and reduced quality of life for months or years after recovery. (See Long-term effects.)

Giuliano and colleagues report that HAP, the second most common hospital-acquired infection, costs the U.S. healthcare system >$3 billion annually. According to McNally and colleagues and the Veterans Administration, the average hospital stay for a patient with HAP ranges from 7 to 10 days, with a mean treatment cost of $58,000 per patient. Haque and colleagues note that HAP accounts for 10% to 15% of infections among 1.7 million patients annually with a 25% to 50% mortality rate. According to Aydemir and colleagues, individuals 65 years of age and older who acquire HAP have an in-hospital mortality prevalence of 32.3% and 30-day mortality of 38.2%.

According to the Joint Commission, one out of every 100 hospitalized individuals (an estimated 21,000 patients) experiences nonventilator-associated HAP (NV-HAP). Of those, approximately 21 million (40%) are older adults, many of whom have cardiovascular issues with multiple chronic comorbidities such as hypertension, arthritis, and pulmonary or kidney disease, which makes them vulnerable to opportunistic infections, including those that originate in the oral cavity.

The HAP and oral care connection

According to the Centers for Disease Control and Prevention, one in five older adults has untreated dental decay and 35.6 million (68%) have periodontal disease. In addition, 14 million (26%) are edentulous or wear dentures, which can affect mastication, nutrition, communication, and quality of life. The oral pathogenic microbiome associated with tooth decay and periodontal disease can migrate to the lungs, leading to HAP.

As described by Rodrigues and colleagues, routine oral care decreases the number of virulent oral organisms, reduces HAP incidence, and, as a result, lowers hospital costs. Research, by Deo and Deshmukh and others, indicates that everyone has approximately 700 oral bacteria, spirochetes, fungi, viruses, protozoa, and phylotypes that replicate every 2 to 3 hours. Colonized and aspirated oropharyngeal pathogens descend into the bronchi, leading to lung infection.

Other contributing risk factors associated with disease-causing oral microbiome include diminished or dysfunctional salivary flow, ineffective cough reflex, dysphagia, and the inability to perform or lack of oral care. Gram-positive bacteria colonize in healthy individuals; however, gram-negative bacteria thrive in the mouths of many hospitalized patients, creating oral dysbiosis. (See What is oral dysbiosis?)

A growing body of research (including from Jablonski and colleagues, Hajishengallis, and Marchesan and colleagues) indicates a link between poor oral care and systemic disease. Contributing risk factors associated with NV-HAP related to oral care include immunosenescence, the patient’s oral condition (dentate status, periodontal disease, xerostomia), functional impairments (dysphagia, neurologic conditions), and cognitive impairment or delirium (which can lead to care resistance). Other factors include COVID-19, smoking, and the use of oral chlorhexidine.

Immunosenescence

Immune systems decline with aging (immunosenescence). During the cell replication cycle, telomeres on DNA strands shorten. Over time, these shortened strands render all cells incapable of replication. One result is a diminished immune system.

As described by Ongrádi and Kovesdi, contributing factors of immunosenescence include smoking, stress, lack of sleep, alcohol use disorder, poor nutrition, and the natural reduction of thymosin, which stimulates the development of white blood cells. Many individuals, as they age, acquire autoimmune diseases such as Type 1 diabetes, rheumatoid arthritis, and lupus.

Liu and colleagues describe the association of immunosenescence with decreased immune cell function, infection, osteoporosis, neurodegenerative disease, and aging. According to Oh and colleagues, T-cells, responsible for systemic protection, decrease due to exhaustion or inflammation. Marchesan and colleagues describe removal of dental plaque via brushing and flossing as playing a key role in supporting the body’s natural defenses.

Dentate status

Brushing and flossing education, preventive services, advances in dental techniques, and fluoride-fortified water and toothpaste have led more older adults to retain their dentition. Monteiro and colleagues found that the presence and location of biological teeth significantly influence the types of individual oral bacteria found in the mouth.

According to Iinuma and colleagues, individuals who wear dentures tend to accumulate more food debris and plaque than dentate individuals. Denture wearers also experience decreased saliva production. Saliva acts as a defense system via pellicle formation, antimicrobial agents, pH balance, and physical cleansing. Wearing dentures overnight doubles the microbial burden, increasing the risk of pneumonia.

Periodontal disease

According to Dental Quality Alliance, gingiva (gum tissue) serves as a barrier to keep bacteria out of the circulatory system. However, approximately 47.2% of adults 30 years and older have periodontal disease, and 70.1% of adults 65 years and older have the condition. Periodontitis (severe periodontal disease) destroys the periodontal ligament, connective tissue, and alveolar bone surrounding the teeth. This damage leads to the formation of periodontal pockets between the tooth and substructures, creating a portal of entry for the pathogenic microbiome to invade the circulatory system.

Once in the bloodstream, these pathogenic biofilms colonize and infect heart valves, form thrombi, create brain abscesses, and cause septicemia. Hajishengallis described the association between oral microbiota and Alzheimer’s disease, diabetes, cancer, stroke, and neurodegenerative diseases. In addition, according to Hajishengallis, patients with periodontal disease have a three times higher prevalence of HAP as a result of aspirated oral bacteria.

Polypharmacy and xerostomia

Saliva serves as an essential component of ecological equilibrium. It moistens food into a bolus for ease in mastication and swallowing, increases commensal bacteria, aids communication and digestion, buffers oral pH, and lubricates and remineralizes teeth.

According to Young and colleagues, 36% of Americans age 65 years or older take five or more medications daily. Over 500 drugs (including antidepressants, diuretics, antihypertensives, statins, antihistamines, cardiovascular medications, oral hypoglycemics, iron supplements, antibiotics, analgesics, and antipsychotics) cause xerostomia, which contributes to the accumulation of plaque.

Without saliva, bacterial plaque becomes tacky and adheres to tooth surfaces, making removal difficult. Ultimately, the irritation caused by plaque can lead to bleeding, which serves as a gateway to the circulatory system. According to Murry and colleagues, the existence of oral pathogenic bacteria in the circulatory system can result in endocarditis, cardiovascular disease, complications during pregnancy and birth, diabetes, osteoporosis, and Alzheimer’s disease. Patients who aspirate this biofilm into their lungs can develop HAP.

Dysphagia

Lyons and Kollef describe the association between dysphagia (difficulty swallowing) with reduced levels of consciousness, risk of stroke, and an increase in the incidence of HAP. Lack of saliva (which increases with age) can lead to and worsen dysphagia. Poulsen and colleagues found that 144 (43.1%) of 334 patients had dysphagia, experienced higher mortality rates, and faced longer lengths of hospital stay. These researchers also found a correlation between dysphagia and pneumonia, chronic obstructive pulmonary disease exacerbation, and malnutrition. Individuals with oropharyngeal dysphagia (when food doesn’t properly move from the mouth to the throat) have more severe outcomes, contributing to poorer health.

Neurologic conditions

Stroke, neurologic conditions, muscular disorders, and tube feeding can impede oral care. They can affect the swallowing reflex and inhibit the cough impulse, preventing respiratory clearance and creating the sensation of suffocation. According to Jensen, facial paresis, poor tongue control, and decreased oral sensations also contribute to choking. Lyons and Kollef noted that patients confined to bed or receiving tube feedings are at a higher risk for aspiration pneumonia. In general, according to Lyons and Kollef, stroke victims receive poor-quality oral care, and mouth care is delegated to the least-qualified staff members.

Cognition and oral care

As individuals age, they may require oral care assistance due to physical disability or cognitive impairment. As described by Jablonski and colleagues, mental decline can reduce the patient’s ability to understand the need to clean their mouths properly, resulting in more visible food debris and plaque. This accumulation increases the risk of gingivitis and periodontal disease due to the proliferation of the oral pathogenic microbiome. Decreasing the risk of infection and preserving the patient’s quality of life requires food and plaque removal.

As cognition declines or hospitalized delirium intensifies, a patient may become agitated and combative. Resistant behaviors include clenching the lips or teeth, turning the head, screaming, grabbing, pushing, hitting, or kicking. When faced with resistance, caregivers may avoid providing oral care assistance, which ultimately leads to increased plaque accumulation and an increased risk of aspiration pneumonia.

COVID-19

According to Kamel and colleagues, an association exists between the severity and prolonged recovery time (≥6 weeks) of COVID-19 infection and poor oral health. Wölfel and colleagues found SARS-CoV-2 replicating in the oropharynx of patients, and Marchesan and colleagues found significant amounts of the virus in the sloughing of oral mucosa.

Smoking

According to Stattin and colleagues, smoking can increase the risk of pneumonia. It induces airway inflammation, impairs the body’s immune response, and weakens mucociliary clearance. Smoking also can exacerbate comorbidity conditions and increase the risk of severe health complications. Smoking cessation and diligent oral care decrease the threat of pneumonia.

Oral chlorhexidine

Oral chlorhexidine (0.12% solution), an antiseptic mouth rinse, reduces gram-positive and gram-negative bacteria, yeast, and fungi. Ogbac found that chlorhexidine reduces the risk of HAP in critically ill patients from 12.5% to 6.25% and is associated with a 1-day shorter stay. A meta-analysis by Pineda and colleagues noted that 78% of gram-negative bacteria are found in HAP, and Pseudomonas aeruginosa is the most common aerobic bacillus associated with HAP. In a study by Tran and Butcher, the intervention group using chlorhexidine for 7 days showed a significant reduction (P<0.001) in oral pathogens from baseline.

However, prolonged use of chlorhexidine may cause adverse effects, including ulcerations, white/yellow lesions, and bleeding mucosa. According to Klompas and colleagues, although oral chlorhexidine is widely used, it’s not currently recommended because of its strong bactericidal and virucidal properties. Klompas and colleagues also noted that oral chlorhexidine creates a dysbiotic environment, killing commensal as well as virulent organisms, and that it is associated with increased mortality. In 16 randomized controlled trials, Dale and colleagues found a trajectory toward increased mortality with oral chlorhexidine rinse.

Because of these studies, medical professionals have begun to question the safety and effectiveness of oral chlorhexidine. In addition, when aspirated into the lungs, chlorhexidine can cause cell injury and acute respiratory distress syndrome. According to Tran and Butcher, no formal guidelines currently exist for chlorhexidine use due to uncertainty of its risk–benefit ratio.

Nursing implications

Nursing practice requires consistent and evidence-based, twice-daily oral care, documented in patients’ electronic health records. To reduce the prevalence of HAP, nurses need only an inexpensive toothbrush, a pea-sized amount of fluoridated toothpaste, and 2 minutes of brushing time twice a day.

However, a meta-analysis by Hoben and colleagues of 15 cross-sectional studies, 13 qualitative studies, seven mixed-methods studies, three one-group pre-post studies, and three randomized controlled trials found that 45% of nurses refused to provide oral care because of patient resistance. Nurses also cited lack of knowledge, education, or training (24%); challenges when providing oral care (26%); lack of time (31%); an aversion to oral hygiene tasks (19%); and insufficient staffing (22%). Other nurses described oral care as unpleasant, said that they avoided it as much as possible, or reported that they rushed through the task.

According to Coker and colleagues, although some nurses note a lack of knowledge as a barrier to providing oral care, a correlation may not exist. Many nurses describe oral hygiene as optional, spontaneous, or variable; that it’s at the nurse’s discretion. Coker and colleagues noted the need for nurses to adhere to minimal oral care standards. They also cited a correlation between nurses’ attitudes and poor patient care; 68% felt the task was unpleasant and 29% believed they had insufficient mouth care training.

According to Jablonski, many fundamental nursing textbooks omit oral care, require updates, or recommend improper practices. For example, several nursing textbooks recommend using foam sponge swabs. However, Canada and some European countries have banned them due to choking and aspiration concerns.

Care plans and guidelines

According to a study by Coker and colleagues, hospital staff rarely check nursing care plans. In addition, most care plans address only oral prosthetics or types of oral assistance needed. Oral care protocols, guidelines, and policies exist on hospital units; however, nurses must be aware of their content.

The American Association of Critical-Care Nurses guidelines state that patients should brush their teeth twice daily with fluoridated toothpaste and use assistive devices (such as a power toothbrush) if they have compromised manual dexterity. The guidelines also state that nurses and other professional caregivers should provide oral care if a patient can’t do so independently. A small head toothbrush enhances ease of caregiver use and reduces trauma for the patient. To address dryness as a result of dehydration, the guidelines recommend moisturizing the patient’s lips and oral mucosa every 2 to 4 hours.

Accurate documentation, foundational to the nursing process, describes and communicates care, guarantees continuity of care, provides legal and ethical accountability, and contributes to research and education. Nurses should document oral care in the patient’s electronic health record to reduce the incidence of HAP and ensure continuity of oral care.

Hospitalized individuals have the fundamental right to be supported or assisted in oral care. However, a study by Gallione and colleagues found oral care the most frequently missed care. According to Wårdh and colleagues, because many nurses view oral hygiene as a low priority for nurses, this care doesn’t occur or isn’t offered. In 2020, the CDC discovered that oral care wasn’t a part of routine night care. Wårdh and colleagues note that adults who don’t receive nightly oral care have a 20% to 35% increased mortality risk. Whereas oral hygiene decreases the incidence of HAP by 40% to 60%.
In a study by Tuuliainen and colleagues, older adults with functional impairments or disabilities who received mouth hygiene assistance experienced improved comfort, increased self-esteem, and enhanced emotional well-being.

Prevention

According to Meehan and McKenna, in addition to toothbrushing every 12 hours with a soft-bristle toothbrush to sweep away pathogenic biofilm, evidence-based practice includes using a sodium bicarbonate (alkaline) toothpaste to help maintain a balanced pH. Normal pH for salvia ranges between 6.2 and 7.6. Age affects the quality and quantity of saliva. For example, dehydration can result in increased acidity.

To reduce the risk of xerostomia and resulting proliferation of gram-negative bacteria, avoid mouthwashes with alcohol. In addition, advise patients to avoid beverages and foods that lower pH, such as soft drinks, white wine, citric fruit juices, American cheese, and cherries.

Standard of care

To prevent HAP, the standard of nursing care must include providing evidence-based oral hygiene to hospitalized patients. Omitting it places these patients at risk for severe, potentially life-threatening illness.

To support nurses in providing oral care for their hospitalized patients, nursing school curriculum and accompanying textbooks must emphasize the oral-systemic link as well as its role in preventing hospital-acquired infections. Nurses who understand how bacteria affects overall health may better appreciate the importance of assisting patients with oral care. Villacorta-Siegal and colleagues recommend working with dental prevention specialists, such as registered dental hygienists, to train nurses in oral assessments as well as proper brushing and flossing techniques and the use of assistive devices.

In addition to cleaning teeth, oral care also helps to remove the thick, white bacterial coating that develops on the tongue as a result of dehydration. This coating inhibits the sense of taste. Brushing and tongue care may help encourage patients to request hydration and food, which ultimately aids recovery and shortens hospital length of stay. Reminding nurses of these benefits may encourage them to provide this oral care.

Omitting oral care is unethical and places patients at risk for HAP, from which they may never recover. The standard of nursing care must include evidence-based, value-based oral hygiene for hospitalized patients to improve safety and care quality.

Susie Keepper is the Impact Evaluation Committee Lead at CareQuest in Oklahoma City, Oklahoma.

American Nurse Journal. 2026; 21(1). Doi: 10.51256/ANJ012606

References

Alja’afreh MA, Mosleh SM, Habashneh SS. Nurses’ perception and attitudes towards oral care practices for mechanically ventilated patients. Saudi Med J. 2018;39(4):379-85. doi:10.15537/smj.2018.4.21749

Aydemir S, Hoşgün D. Evaluation of the factors affecting long-term mortality in geriatric patients followed up in intensive care unit due to hospital-acquired pneumonia. Medicine. 2022;101(38):e30645. doi:10.1097/MD.0000000000030645

Centers for Disease Control and Prevention. Oral health in healthcare setting to prevent pneumonia toolkit. 2024. cdc.gov/hai/prevent/Oral-Health-Toolkit.html

Coker E, Ploeg J, Kaasalainen S, Carter N. Nurses’ oral hygiene care practices with hospitalised older adults in postacute settings. Int J Older People Nurs. 2017;12(1):e12124. doi:10.1111/opn.12124

Dale CM, Rose L, Carbone S, et al. Effect of oral chlorhexidine de-adoption and implementation of an oral care bundle on mortality for mechanically ventilated patients in the intensive care unit (Choral): A multi-center stepped wedge cluster-randomized controlled trial. Intensive Care Med. 2021;47(11):1295-1302. doi:10.1007/s00134-021-06475-2

Dental Quality Alliance. Measuring Oral Healthcare Quality for Older Adults. 2021. ada.org/-/media/project/ada-organization/ada/ada-org/files/resources/research/dqa/educationalresources/measuring_oral_healthcare_quality_in_older_adults_report.pdf

Deo P, Deshmukh R. Oral microbiome: Unveiling the fundamentals. J Oral Maxillofac Pathol. 2019;23(1):122. doi:10.4103/jomfp.JOMFP_304_18

Gallione C, Bassi E, Basso I, et al. Missing fundamental nursing care: What’s the extent of missed oral care? A cross-sectional study. Nurs Rep. 2024;14(4):4193-4206. doi:10.3390/nursrep14040305

Giuliano KK, Baker D, Thakkar-Samtani M, et al. Incidence, mortality, and cost trends in nonventilator hospital-acquired pneumonia in medicaid beneficiaries, 2015-2019. Am J Infect Control. 2023;51(2):227-30. doi:10.1016/j.ajic.2022.06.016

Hajishengallis G. Interconnection of periodontal disease and comorbidities: Evidence, mechanisms, and implications. Periodontol 2000. 2022;89(1):9-18. doi:10.1111/prd.12430

Haque M, Sartelli M, McKimm J, Bakar MA. Health care-associated infections—An overview. Infect Drug Resist. 2018;11:2321-33. doi:10.2147/IDR.S177247

Hoben M, Clarke A, Huynh KT, et al. Barriers and facilitators in providing oral care to nursing home residents, from the perspective of care aides: A systematic review and meta-analysis. Int J Nurs Stud. 2017;73:34-51. doi:10.1016/j.ijnurstu.2017.05.003

Iinuma T, Arai Y, Abe Y, et al. Denture wearing during sleep doubles the risk of pneumonia in the very elderly. J Dent Res. 2015;94(3 Suppl):28S-36S. doi:10.1177/0022034514552493

Jablonski RA. Oral health and hygiene content in nursing fundamentals textbooks. Nurs Res Pract. 2012;2012:1-7. doi:10.1155/2012/372617

Jablonski RA, Kolanowski AM, Azuero A, Winstead V, Jones‐Townsend C, Geisinger ML. Randomised clinical trial: Efficacy of strategies to provide oral hygiene activities to nursing home residents with dementia who resist mouth care. Gerodontology. 2018;35(4):365-75. doi:10.1111/ger.12357

Jablonski RA, Kolanowski A, Therrien B, Mahoney EK, Kassab C, Leslie DL. Reducing care-resistant behaviors during oral hygiene in persons with dementia. BMC Oral Health. 2011;11(1):30. doi:10.1186/1472-6831-11-30

Jensen M. Chronic obstructive pulmonary disease: Pathophysiology, diagnosis, and advances in management. Public Health Spectrum. 2024;1(1):e21217. docentra.com/copd

Joint Commission. Preventing non-ventilator hospital-acquired pneumonia. Quick Safety, 61. digitalassets.jointcommission.org/api/public/content/711cd7f92bc3430e9072110c7eab433c?v=5aa31e57

Kamel AHM, Basuoni A, Salem ZA, AbuBakr N. The impact of oral health status on COVID-19 severity, recovery period and C-reactive protein values. Br Dent J. 2021;24:1-7. doi:10.1038/s41415-021-2656-1

Kim G, Baek S, Park HW, Kang EK, Lee G. Effect of nasogastric tube on aspiration risk: results from 147 patients with dysphagia and literature review. Dysphagia. 2018;33(6):731-8. doi:10.1007/s00455-018-9894-7

Klompas M, Branson R, Cawcutt K, et al. Strategies to prevent ventilator-associated pneumonia, ventilator-associated events, and nonventilator hospital-acquired pneumonia in acute-care hospitals: 2022 Update. Infect Control Hosp Epidemiol. 2022;43(6):687-713. doi:10.1017/ice.2022.88

Liu Z, Liang Q, Ren Y, et al. Immunosenescence: Molecular mechanisms and diseases. Signal Transduct Target Ther. 2023;8(1):200. doi:10.1038/s41392-023-01451-2

Lyons PG, Kollef MH. Prevention of hospital-acquired pneumonia. Curr Opin Crit Care. 2018;24(5):370-8. doi:10.1097/MCC.0000000000000523

Lyons M, Smith C, Boaden E, et al. Oral care after stroke: Where are we now? Eur Stroke J. 2018;3(4):347-54. doi:10.1177/2396987318775206

Marchesan JT, Byrd KM, Moss K, et al. Flossing is associated with improved oral health in older adults. J Dent Res. 2020; 99(9):1047-53. doi:10.1177/0022034520916151

McNally E, Krisciunas GP, Langmore SE, Crimlisk JT, Pisegna JM, Massaro J. Oral care clinical trial to reduce non–intensive care unit, hospital-acquired pneumonia: Lessons for future research. J Healthc Qual. 2019;41(1):1-9. doi:10.1097/JHQ.0000000000000131

Meehan C, McKenna C. Preventing hospital-acquired pneumonia. Am Nurse J. 2020. myamericannurse.com/preventing-hospital-acquired-pneumonia/

Monteiro DR, De Souza Batista VE, Caldeirão ACM, Jacinto RDC, Pessan JP. Oral prosthetic microbiology: aspects related to the oral microbiome, surface properties, and strategies for controlling biofilms. Biofouling. 2021;37(4):353-71. doi:10.1080/08927014.2021.1912741

Murakami S, Mealey BL, Mariotti A, Chapple ILC. Dental plaque–induced gingival conditions. J Clinic Periodontology. 2018;45(S20). doi:10.1111/jcpe.12937

Murry PE, Coffman JA, Garcia-Godoy F. Oral pathogens’ substantial burden on cancer, cardiovascular disease, Alzheimer’s, diabetes, and other systemic diseases: A public health crisis—A comprehensive review. Pathogens. 2024;13(12):1084. doi:10.3390/pathogens13121084

National Heart, Lung, and Blood Institute. Pneumonia recovery. March 24, 2022. nhlbi.nih.gov/health/pneumonia/recovery

Ogbac MK, Arquiza J. Effect of oral chlorhexidine in preventing hospital-acquired pneumonia among non-intubated patients in the Philippines. Eur Respir J. 2018;52(suppl 62):PA2641. doi:10.1183/13993003.congress-2018.PA2641

Oh SJ, Lee JK, Shin OS. Aging and the immune system: the impact of immunosenescence on viral infection, immunity and vaccine immunogenicity. Immune Netw. 2019;19(6):e37. doi:10.4110/in.2019.19.e37

Ongrádi J, Kövesdi V. Factors that may impact on immunosenescence: An appraisal. Immun Ageing. 2010;14(7):7. doi:10.1186/1742-4933-7-7

Pineda LA, Saliba RG, El Solh AA. Effect of oral decontamination with chlorhexidine on the incidence of nosocomial pneumonia: A meta-analysis. Crit Care. 2006;10(1):R35. doi:10.1186/cc4837

Poulsen SH, Rosenvinge PM, Modlinski RM, Olesen MD, Rasmussen HH, Holst M. Signs of dysphagia and associated outcomes regarding mortality, length of hospital stay and readmissions in acute geriatric patients: Observational prospective study. Clin Nutr ESPEN. 2021;45:412-419. doi:10.1016/j.clnesp.2021.07.009

Rodrigues DS, De Souza PTDR, Orsi JSR, Souza PHC, Azevedo-Alanis LR. Oral care to reduce costs and increase clinical effectiveness in preventing nosocomial pneumonia: A systematic review. J Evid Based Dent Pract. 2023;23(2):101834. doi:10.1016/j.jebdp.2023.101834

Rope K, Gatta F, Gopal A. What are the complications of pneumonia? WebMD. May 14, 2024. webmd.com/lung/complications-pneumonia

Stattin K, Eriksson M, Frithiof R, et al. Smoking is associated with a higher risk of contracting bacterial infection and pneumonia, intensive care unit admission and death. PLoS One. 2024;19(5):e0302505. doi:10.1371/journal.pone.0302505

Tran K, Butcher R. Chlorhexidine for oral care: A review of clinical effectiveness and guidelines. Canadian Agency for Drugs and Technologies in Health. 2019. https://www.ncbi.nlm.nih.gov/books/NBK541430/

Tuuliainen E, Autonen-Honkonen K, Nihtilä A, et al. Oral health and hygiene and association of functional ability: A cross-sectional study among old home care clients. Oral Health Prev Dent. 2020;18(2):253-62. doi:10.3290/j.ohpd.a43353

Villacorta-Siegal N, Joseph K, Gardner S, et al. Integration of a dental hygienist into the interdisciplinary long-term care team. Gerodontology. 2024;41(1):125-40. doi: 10.1111/ger.12734

Wårdh I, Hallberg LR, Berggren U, Andersson L, Sörensen S. Oral health care—A low priority in nursing. In-depth interviews with nursing staff. Scand J Caring Sci. 2000;14(2):137-42. doi:10.1111/j.1471-6712.2000.tb00574.x

Wölfel R, Corman VM, Guggemos W, et al. Virological assessment of hospitalized patients with COVID-2019. Nature. 2020;581(7809):465-9. doi:10.1038/s41586-020-2196-x

Young EH, Pan S, Yap AG, Reveles KR, Bhakta K. Polypharmacy prevalence in older adults seen in United States physician offices from 2009 to 2016. PLoS ONE. 2021;16(8):e0255642. doi:10.1371/journal.pone.0255642

Zhu Z, Yang Z, Qi X, Mao W, Pei Y, Wu B. Association between oral hygiene behaviors and cognitive decline in adults: A systematic review and meta-analysis. J Adv Nurs. 2025;81(5):2277-89. doi:10.1111/jan.16525

Key words: hospital-acquired pneumonia, aspiration, older adults, oral biofilm, oral care