Recuperación

A number of studies have investigated the relationship between respiratory tract infection and dental factors such as plaque, caries, and periodontitis. Unfortunately, it is difficult to synthesise the results from these studies into a coherent picture to explain the relationships between these variables because of inconsistent results and varying endpoints. Dentate persons appear to have higher rates of respiratory infection [44, 86], and AP appears to be associated with increased tooth number in dentate patients [29]. One study found similar rates of pneumonia in dentate versus edentulous (no remaining dentition) patients, though rates in the latter were lower [152]. However, other studies either found no relationship with tooth number [152], or have not reported the relationship between HAP and number of teeth [30, 42], inferring that no relationship was found. Edentulous patients were more likely to be colonised with S. pneumoniae, MRSA or C. albicans in one study[152], but samples were taken from buccal mucosa in edentulous patients and form dental plaque in dentate patients, which may explain this finding. AP has been associated both with number of decayed teeth [29, 30], and salivary S. sobrinus [29] in dentate patients. Nosocomial infections in ICU patients have also been associated with caries [42]. In contrast, presence of respiratory pathogens was not associated with number of teeth [37, 147] or caries [37] in other studies.

Respiratory tract infections have been associated with heavier dental plaque deposits [44, 45] and with presence of respiratory commensal pathogens in dental plaque [147]. However, no relationship was found between presence of respiratory commensal pathogens in dental plaque and heavier dental plaque [42, 153]. Aspiration pneumonia has also been shown to be associated with P. gingivalis in dental plaque, and diabetes mellitus in dentate persons [29], but was not associated with increased gingival bleeding index. Presence of respiratory commensal pathogens in community dwelling older Japanese

persons was associated with positive occult salivary blood [37]. In persons with learning difficulties, pneumonia was associated with an increased Oral

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Assessment Guide (OAG) score, with individual components of “tongue” and “swallow” being significantly higher, and “gingiva” trending towards

significance in those with pneumonia [152]. However, few studies have included measures of gingival health, and it is difficult to draw conclusions because of this.

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Table 7. Observational studies linking pneumonia or presence of respiratory pathogens in oral cavity with dental factors

Setting Sample

size Findings Clinic, ward and

institution, US [29]

357 AP in dentate patients associated with: Number of teeth, number of decayed units, S. sobrinus in saliva, P. gingivalis in dental plaque, diabetes mellitus, periodontal disease.

Clinic, ward and nursing home patients, US [30]

189 AP associated with number of decayed teeth and multiple medical diagnoses in dentate patients. No link with xerostomia.

Patients with learning difficulties

63 Pneumonia associated with microorganisms ( S. pneumoniae, MRSA, P. melaninogenica, C. albicans by PCR) at baseline, worse OAG score, increased age and enteral feeding. Only OAG score

associated in multivariate analysis (OR 1.6). No patient had caries.

Nursing home,

Switzerland [44] 302 Respiratory tract infection associated with being dentate or needing to visit the dentist in emergency.

Dentate patients with RTI had significantly higher plaque scores.

ICU patients,

France [42] 57 Dental plaque increased (non-significantly) over time in ICU. High caries score (but not plaque score)

associated with nosocomial infection.

No correlation between plaque score and caries score.

No correlation between plaque colonisation and plaque score.

Dental plaque colonisation with AGNB but not S. aureus associated with subsequent infection. Plaque colonisation at day 5 associated with subsequent nosocomial infection (RR 9.6) ICU patients, US

[153] 34 Colonisation with respiratory pathogens (MRSA, P. aeruginosa, AGNB) in 22/34 patients was associated with antibiotic therapy but not with increased dental plaque score or illness severity. Independent

living patients, Japan [37]

265 Opportunistic respiratory pathogens (P. aeruginosa, S. marcescens, K. pneumoniae,C. albicans) detected by culture of single tongue sample more common if occult blood in saliva and increased age.

No association with salivary flow (stimulated or unstimulated), caries, denture wearing or salivary pH.

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Setting Sample

size Findings Nursing home,

US [147]

28 Colonisation with S. aureus, E. cloacae, P.

aeruginosa, K. pneumoniae or E. coli in 7/28, >1% of aerobic flora in 4/28.

Cultures of dental and denture plaque, and buccal mucosa samples.

Presence of respiratory organisms commoner if high plaque score or COPD, no difference in number of teeth or if dentures present. Institutionalised

and long term hospitalised patients, Japan [154]

343 HAP associated with Clusters C and D

(Prevotella, Treponema, Veillonella) compared with cluster A (Streptococcus) detected by Terminal Restriction Fragment length polymorphism Nursing home residents, health older and younger adults, Japan [151]

54,21,22 Higher Staphylococcal species but lower P.

aeruginosa seen in those with poorer oral hygiene. Professional oral hygiene only reduced C.

albicans significantly. Nursing home

residents, Japan [155]

71 Pneumonia commoner in those with higher tongue plaque.

Higher salivary bacterial counts seen in those with higher tongue plaque.

Hospitalised patients awaiting cardiac

revascularisation [150]

30 P. aeruginosa commoner in patients with <14 teeth Co-colonisation of P. aeruginosa and Acinetobacter spp. observed

RTI= respiratory tract infection, ICU=Intensive Care Unit, AGNB=Aerobic gram negative bacilli, RR=relative risk, COPD= Chronic obstructive pulmonary disease, OAG= Oral assessment guide

Despite the contradictory and incomplete nature of the above findings, it does appear that there is a relationship between respiratory tract infection and oral health, but the relationship may be indirect and complex. These findings have led some authors to hypothesise that dental plaque may be a stable reservoir of respiratory commensal pathogens, and that removal of plaque [47, 156-161] or disinfection of the oral surfaces might reduce the risk of respiratory infection. A number of oral hygiene intervention studies have been undertaken in ventilated and non-ventilated persons, and are described below.

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