The present audit showed an overall beneficial effect of ozone application with 80% of the patients showing significantly (P < 0.001) improved BPE scores after gaseous ozone application. Additionally, pocket depth analysis revealed that 32% of the deepest pockets improved by more than three millimetres, 64% by one to two millimetres and 4% did not improve or deteriorated. The results support the use of ozone as an adjunct to mechanical treatment in periodontal patients in agreement with other studies [9,10].