The aim of the present investigation was to analyse the effect of
subgingival scaling and
root planing in subjects who prior to treatment exercised meticulous supragingival plaque control. 300 subjects were examined at baseline and after 1 and 2 years without treatment. After the year 2 examination, 62 subjects were randomly selected for
therapy. They were given detailed instruction in proper self-performed toothcleaning measures and were carefully monitored during the subsequent 2 years. Following the year-4 examination, 2 quadrants, 1 maxillary and 1 mandibular in each subject, were randomly selected for additional
therapy. The teeth in the selected quadrants were exposed to
subgingival scaling and
root planing. The subgingival
therapy was repeated until a site no longer bled on gentle probing. This basic
therapy was completed within a 2-month period. All subjects were re-examined after another 12-month interval. The examinations at year 4 and 5 included assessment of plaque,
gingivitis, probing pocket depth and analysis of samples obtained from the subgingival microbiota at 134 selected sites. The findings from the present study demonstrated: (i) that
subgingival scaling and
root planing were effective in eliminating subgingival plaque and
gingivitis; (ii) that professional
therapy resulted in a pronounced reduction of probing depth at sites which at year 4 had a probing depth > 3 mm; (iii) that in non-scaled quadrants, the extension of self-performed plaque control resulted in a continued improvement of the periodontal conditions at sites which at year 4 were < 5 mm deep.