To make sure that the observed therapeutic effect was that of ozone patients were also instructed not to use any of the available antimicrobials after the treatment with ozone. It is known that agents like chlorhexidine are being used as part of the chemo-mechanical treatment approach of chronic periodontitis and can significantly reduce the depth of deep and medium-deep pockets [22]. Patients were given oral hygiene instructions and were asked to keep their oral hygiene daily diary.