A new assessment from the Cochrane Oral Health Group reports weak evidence for cleaning above and under the gums (scaling and root planing) in terms of managing gingivitis and periodontal disease. Only 3 studies met the criteria for randomized controlled trials for this hygiene procedure.
But one can quibble with the Cochrane assessment. The studies which Cochrane reviewed involved healthy adults. Scaling healthy adults is not appropriate nor would it be effective. Its akin to managing an infection in a patient who has no infection.
Hygiene and dentistry must establish more clinical evidence from high risk patients. Why? Because insurers, governments and payers are demanding it. Secondly, because conducting any treatment without regard to need/risk, is highly inefficient, wasteful, and leads eventually to empty waiting rooms.
Medicine is struggling to find clinical risk in its caseload of patients, and then struggling even harder to prevent the progress of that risk into disease. Medicine is now strongly incented to do so, under the terms of value driven care or sometimes called incentivized capitation.
Dentistry and hygiene are next in line.