Oral biofilms are the primary cause of dental caries and periodontal diseases. This RCT looked at the effect of a multichannel oral irrigator (MCOI) (a new oral hygiene device which injects clean water onto the teeth at an angle of 45°) on periodontal health in 29 healthy participants randomly divided into two groups. Saliva samples were analysed in the MCOI group and the control group and changes in the oral microbiota investigated with a focus on gingival inflammation. It was assumed that water irrigation using this new device may lower the accumulation of oral biofilms. However, the effectiveness of this new device in decreasing dental plaque was not determined because the MCOI group showed accumulation of plaque in the oral cavity and increased levels of opportunistic pathogens called Captocytopaga species involved in periodontal disease. Streptococcus species also showed an increase in the MCOI group and other bacteria were reduced. The authors agree that these conflicting trends imply the need for a longitudinal study over a longer period as three days was too short to assess gingival status change, let alone detect any changes to the periodontal state. Overall the oral microbiome and oral hygiene is important and relevant to health as certain patients with low dexterity such as the elderly and those with disabilities may struggle with thorough plaque removal so assisted devices to clean the oral cavity are needed. Furthermore this can also apply to patients with Alzheimer disease, dementia and autism.