text: A review of the research literature on the question concluded "he research evidence is not of sufficient quality to reach any conclusions regarding the beneficial and adverse effects of routine scaling and polishing for periodontal health and regarding the effects of providing this intervention at different time intervals" This conclusion was reaffirmed when the 2005 review was updated in 2007. Thus, any general recommendation for a frequency of routine cleaning (e.g. every six months, every year) has no empirical basis.