In previous studies on H pylori positivity in dental plaque, we found no information about the objective criteria, such as periodontal index and plaque index
, that would quantify the periodontal hygiene.
They scored colour reaction on the basis of a colour chart, and those scores were compared with scores from traditional clinical evaluation methods, such as plaque index
, gingival index, attachment levels and bleeding on probing.
In addition, the analyses for 3- and 5-year-olds were also adjusted for parents' level of education (high = university, intermediate = high school, low = upper secondary school), snacks between principal meals (0-3 or [greater than or equal to] 4 per day) and plaque index
(low = 0-4%, intermediate = 4.
After examination and being matched for disease status, plaque index
, age and gender, participants were assigned to either a control or test group.
OH was assessed using the plaque index
(PI) of Silness and Loe  on the six Ramfjord teeth (16,12,24,36,32,44-proximal, buccal, lingual) with the use of a disclosing agent (score 0=no dental plaque in the gingiva area, score 1= a film of dental plaque adhering to the free gingival margin (only upon probing), score 2=moderate accumulation of dental plaque at the gingival margin (seen by naked eye), score 3=abundant dental plaque in the gingival margin).