Research on the potential contribution of oral care in preventing ventilator-associated pneumonia (VAP) has led to the generally accepted practice of using oral antiseptic agents [1]; however, the value of toothbrushing remains controversial.

Dr Gu and colleagues [2] investigated the effect of oral care with versus without toothbrushing on VAP prevention by meta-analysis, and found toothbrushing not to significantly reduce VAP incidence (risk ratio 0.77, 95% confidence interval 0.50 to 1.21). We feel, however, uncomfortable with the message that '... there is currently a lack of evidence to support toothbrushing in patients receiving mechanical ventilation'. This phrase might instigate healthcare professionals to abstain from brushing patients' teeth while the primary objective of toothbrushing is to maintain oral health, not to prevent VAP. A potential VAP risk reduction should rather be considered as a favorable side effect.

Also, two studies [3, 4] in which VAP diagnosis was exclusively based on a Clinical Pulmonary Infection Score (CPIS) ≥6 were included in the meta-analysis. The CPIS is known to have moderate performance as well as considerable interobserver variability, and has been shown not to differentiate adequately between patients with VAP and systemic inflammatory response syndrome [5]. Our concern is well illustrated by Munro et al. [4] reporting to have unexpectedly found 115/192 patients with CPIS ≥6 at day 1 of data collection. This diagnostic issue may have yielded a vast overestimation of VAP rates and could have been acknowledged. We encourage researchers to use more stringent definitions for VAP diagnosis in future investigations.