Oral care strategies for the average, healthy individual are well known: brush twice per day, floss once per day, and see the dentist every 6 months for a check-up. However, for medically compromised persons who are hospitalized or residing in nursing homes, these basics are often set aside and oral care becomes much more complex, especially when individuals cannot care for themselves. The question then becomes: What specific strategies can be used to achieve optimum oral health, particularly to avoid an increase in the incidence of aspiration pneumonia? The literature provides a number of references on the use of oral rinses and various methods of oral cleansing.
Literature reviews conducted in 2003 , 2006 , and 2008  reported that improved oral hygiene and frequent professional oral health care reduces the progression or occurrence of respiratory diseases and the overall incidence of aspiration pneumonia by an average of 40% among high-risk elderly adults living in nursing homes in intensive care units (Level 1, grade A recommendation), though interventions included mechanical plaque removal (i.e., tooth brushing, swabbing), topical chemical disinfection, and/or use of antibiotics. Available results from randomized controlled trials linking oral hygiene status to pneumonia and respiratory tract infections in elderly people offer strong evidence that providing mechanical oral hygiene may prevent one in ten cases of death from pneumonia in dependent elderly people, and they indicate a largely similar effect on the prevention of pneumonia . Breaking down the research into those investigating chemical versus mechanical intervention, therefore, seems warranted.
Chemical Means of Intervention
In the mid-1970s, 0.12% chlorhexidine gluconate (CHX) under the brand name of Peridex® was approved by the U.S. Food and Drug Administration and introduced for use by individuals undergoing periodontal treatment and dental implant surgery, as a presurgical and general antiseptic hand scrub [23, 24], umbilical cord cleanser, and for treating burns , cuts, and even acne. CHX is a broad-spectrum antiseptic rinse that reduces both Gram-positive and Gram-negative bacteria. What is uniquely important about chlorhexidine is its substantivity, i.e., its ability to remain chemically active on tissue for up to 6 h . Periodontists and oral surgeons prescribed the antimicrobial mouth rinse to decrease the oral bacterial burden for improved postsurgical healing and for long-term maintenance in some cases, such as dental implants. Additional uses of CHX in the oral cavity have included treatment of aphthous and herpetic ulcers , as an additive in dressings used for third molar extraction sites , as an irrigation for dry socket sites , and to assist in the management of oral conditions related to leukemia  and cancer patients receiving radiation therapy in the head and neck region.
In 1996, DeRiso et al.  conducted a study using 0.12% CHX rinses for pre- and postoperative heart surgery patients. A 0.5-fluid-ounce oropharyngeal rinse was provided to the CHX group two times per day for 30-s rinses (no ingestion). If unable to rinse, the CHX was rigorously applied to the patient’s buccal, pharyngeal, gingival, tongue, and tooth surfaces by a staff member. In the CHX group, results demonstrated a decrease in nosocomial infections by 65% and Gram-negative organisms involved in nosocomial infections by 59%. CHX subjects also demonstrated a decrease in total respiratory tract infections by 69% and Gram-negative organisms associated with respiratory tract infections by 67%. The use of nonprophylactic IV antibiotics decreased by 43% and there was a reduction in the mortality rate as well. There was no change in bacterial antibiotic resistance patterns for either subject group.
In a 2000 study , the European 0.2% chlorhexidine gluconate was applied in gel form to dentate patients in the intensive care unit who were mechanically ventilated. After mouth rinsing and oropharyngeal suctioning, the nurse applied the gel to tooth and gingival surfaces three times a day. The gel was left in place and the patient was instructed not to rinse, eat, or drink. Even without the mechanical elimination of plaque by tooth brushing, plaque scores progressively decreased, indicating a positive result for decreased plaque growth with the use of chlorhexidine gluconate. Because ICU patients are often immunologically compromised, the mechanical action of the toothbrush may place the patient at risk for bacteremia, which is sound reasoning for the use of CHX as the major source of oral decontamination. In this study, there was a decreased rate of ICU-related nosocomial infections as well as a decrease in ventilator-associated pneumonia.
ICU patients on mechanical ventilation were examined in a study  to determine the effect of decreased oropharyngeal colonization on the incidence of ventilator-associated pneumonia (VAP). A study group was treated prophylactically with a topical antimicrobial mixture of 2% gentamycin, 2% colistin, and 2% vancomycin in an Orabase® suspension. Orabase® without antibiotics was applied as a placebo to two control groups. The mixture was applied by gloved finger to the buccal cavities and oropharynx every 6 h beginning within 24 h of intubation. The study continued until extubation or death, and normal oral hygiene procedures were provided to all patients. In the study group, topical application of the Orabase® antibiotic mixture reduced the microbial colonization in the oropharynx by 75% and in the trachea by 52%. Without affecting the gastrointestinal colonization, treatment prevented acquired oropharyngeal colonization by 10%. Incidences of VAP were 10% in the study group, 31% in control group 1, and 23% in control group 2.
A more recent randomized controlled trial  that included 207 mechanically ventilated patients looked at the effectiveness of oral decontamination with 2% chlorhexidine (CHX) solution for the prevention of VAP. Patients in the chlorhexidine group received oral care four times per day that involved brushing the teeth, suctioning any oral secretions, and rubbing the oral mucosa with 15 ml of a 2% chlorhexidine solution. Patients in a normal saline group received the same oral care regimen except that their procedures used normal saline solution instead of chlorhexidine solution. The incidence of VAP was 4.9% in the CHX group and 11.4% in the normal saline group. The mean number of cases of VAP was 7 episodes per 1,000 ventilator days in the CHX group and 21 episodes per 1,000 ventilator days in the normal saline group. In all patients, VAP was caused by Gram-negative bacilli with oropharyngeal colonization which was shown to be lower in the CHX group than in the normal saline group. The overall mortality rate for the patients in the CHX group was 32.3% compared with 35.2% for the normal saline group. Although oral decontamination with CHX reduced the risk of VAP in patients who received mechanical ventilation, no significant differences were noted regarding the duration of mechanical ventilation, length of ICU stay, or mortality rate. Nevertheless, oral decontamination with CHX for the prevention of VAP is considered a cost-effective strategy as the cost of the solution is far less than the cost of antibiotic therapy to treat an episode of VAP.
The effectiveness of a 0.12% chlorhexidine gluconate rinse versus Listerine® rinse was reported in 2007 . In a group treated with CHX, patients undergoing open heart surgery showed a 52% reduction in the rate of nosocomial pneumonia versus the Listerine® group. In patients who were intubated for over 24 h, the rate of nosocomial pneumonia was 72% lower in the CHX group versus the Listerine® group. These results demonstrated a lower rate of nosocomial pneumonia for patients treated with chlorhexidine gluconate versus those treated with Listerine® rinse.
Only one study, to our knowledge, has reported negative findings with CHX . In that study, 0.2% CHX gel was applied three times per day and did not reduce the incidence of VAP. However, inclusion criteria allowed patients with pre-existing infections to be enrolled. Sixty-eight percent of participants entered the study with exacerbated chronic bronchitis in COPD and/or community-acquired pneumonia.
Even though the majority of studies indicate positive results with the use of antimicrobial oral rinses for the reduction of aspiration pneumonia, the question remains as to if, when, how, and for whom a rinsing protocol should be implemented.
Mechanical Means of Intervention
The first mechanical line of defense is usually the toothbrush with the occasional addition of dental floss. Unfortunately, for persons who are ill, debilitated, and/or cognitively impaired, medical needs and other personal care needs outweigh oral care needs and even basic tooth brushing is forgotten or set aside. However, if improved oral care can improve or sustain a person’s medical condition, specifically avoid aspiration pneumonia, it bears investigation.
Dentate and edentate subjects  were assigned to an oral care group or a no oral care group. After each meal, in the oral care group, nurses or caregivers cleaned the patients’ teeth, palatal and mandibular mucosa, and tongue dorsum for 5 min by toothbrush. For patients with dentures or partials, the prostheses were cleaned with a denture brush after each meal and once per week with denture cleanser. For those patients unable to tolerate tooth brushing, the oropharynx was swabbed with 1% povidone iodine. Plaque and calculus removal was performed by dentists/dental hygienists once per week. At follow-up, pneumonia, febrile days, and death from aspiration pneumonia decreased in patients who received oral care. Interestingly, activities of daily living (ADLs) and cognitive functions also seemed to improve with oral care (see Table 3 for data comparisons between the oral care versus no oral care groups in dentate and edentate patients).
Professional oral care (POC) by dental professionals has been shown effective in reducing oral pathogens partly responsible for aspiration pneumonia in medically compromised patients. To further define POC and clarify the optimum frequency with which it should be delivered, Ueda et al.  conducted a study of 105 nursing home patients. Of these patients, 55 were positive for oral Candida, which can be related to a number of possible factors, including poor oral hygiene, systemic malnutrition as opportunistic infection, or a fall in host resistance. POC was provided by dentists or dental hygienists via the use of an interdental brush, an “engine” brush (mechanical), and a scaler for calculus deposits. Sponge brushes were used to cleanse the tongue, palate, lips, and oral mucosa. For dentures and partials, surface debris was removed with a denture brush. Toothpastes and rinses were not used. The patients were divided into five groups and POC was provided at 1-, 2-, 3-, 4-, and 6-week intervals, respectively. Oral hygiene improvement rates decreased as POC intervals increased. Nursing homes generally do not have existing dental services (dentists and/or dental hygienists) to provide examinations or administer care. The researchers divided the results into three categories as follows: (1) short-term care, which consisted of POC provided once per week for 12 consecutive weeks, resulted in an overall improvement in the oral condition and eradication of Candida; (2) medium-term care, which consisted of POC provided once every 2 weeks for 20 weeks, resulted in overall improvement in oral condition and was considered to be the optimum interval for maintenance; (3) long-term care, which consisted of POC provided once every 3–4 weeks and was beneficial only if the patient’s Functional Independence Measure (FIM) was over 3, indicating that the patient could take responsibility for his/her own effective oral care.
Another study  sought to determine whether improved oral care had any effect on the cough reflex and, ultimately, on aspiration pneumonia. Fifty-nine elderly nursing home patients were enrolled: 30 in the intervention group and 29 in the control group. Subjects in the intervention group were provided oral care (mechanical cleaning of teeth and gingiva) by caregivers after each meal for 1 month. The control group subjects performed their own oral care for the same period of time. Citric acid was used to test the cough reflex sensitivity of all subjects for baseline measurements and again at the end of the 30 days. End results for the intervention group showed higher cough reflex sensitivity than at baseline as well as higher sensitivity levels than the control group. This indicates that if aspiration pneumonia and cough are related, then improved oral care can increase cough reflex sensitivity, which in turn may decrease the potential for aspiration pneumonia.
Adachi et al.  conducted a study of elderly patients from two nursing homes. Professional oral hygiene care (POHC) was provided once per week by dental hygienists and included mechanical cleaning with electric toothbrushes with an automatic water supply, an interdental brush, and a sponge brush used on the teeth, buccal mucosa, tongue, and dentures. Nurses took the body temperatures of the subjects daily at 7:00 a.m. and 3:00 p.m. Six-month results indicated that POHC reduced the prevalence of fevers and lowered the prevalence of fatal pneumonia in the test group more so than in the control group. Influenza rate was also reduced, as were the numbers of anaerobic bacteria and the enzymatic activities in saliva, which can inhibit absorption of the cold virus into airway membranes.
The Toothette®, a soft sponge on a swab-like stick, is frequently used by nurses and Certified Nurse Assistants (CNAs) for oral care in hospitals and nursing homes. Unfortunately, the Toothette® does not remove plaque as effectively as tooth brushing, and since tooth brushing skills are generally not taught to nurses and support staff, the proliferation of bacteria can occur. Fields  compared the rates of VAP in patients whose teeth were brushed three times a day (every 8 h) with those of patients who received daily tooth brushing and oral care with Toothette®. Patients in the control group received “usual care,” which could include daily tooth brushing along with the use of the Toothette® as needed. For the intervention group, nurses were instructed on the importance of oral care and told to brush the patient’s teeth, tongue, and hard palate with a toothbrush and toothpaste for at least 1 min at three specified times during the day. They were then to use the Toothette® to swab the patient’s teeth, tongue, and hard palate for at least 1 min. The VAP rate for the intervention group dropped to 0% per 1,000 ventilator days and was sustained for 6 months, demonstrating the efficacy of tooth brushing as a means to remove plaque-harboring bacteria, thus preventing VAP.
One study—conducted in 2009  to determine the effectiveness of adding the use of an electric toothbrush to standard oral care with 0.12% chlorhexidine digluconate for the prevention of VAP—yielded negative results for mechanical intervention. Two groups of comparable patients (n = 147) were studied and the findings demonstrated that the addition of electric tooth brushing to standard oral care with 0.12% chlorhexidine digluconate was not effective for the prevention of VAP in that the groups did not differ significantly in mortality, antibiotic-free days, duration of mechanical ventilation, or hospital ICU length of stay (CI = 0.41–1.73).
Given the overall conclusions of the reviewed literature that supports improved oral care and its relationship to the decreased incidence of respiratory pathogens, the next course of inquiry regarding nursing home patients is to determine who is responsible for daily oral care and how will it be implemented.