Patients will be recruited for the study based on the Inclusion and Exclusion criteria.

•Patients will receive information about the etiology of periodontal disease and need for probiotic therapy and informed written consent will be taken.

•Patients will be recalled for saliva sample collection for assessment of IL-6 and plaque sample collection for assessment of Porphyromonas gingivalis, Bacillus coagulans & Streptococcus salivarius and phase I therapy.

TREATMENT PROTOCOL

•Following collection of saliva sample and subgingival plaque sample, clinical parameters like plaque index, gingival index, probing pocket depth and clinical attachment level will be measured and recorded in a proforma.

•After recording of baseline parameters, patients will be randomly allocated to test and control group using a randomization table.

•To maintain full blinding of results the randomization code will be held by the guide remotely from all assessments and will not be broken until all data has been collected and all analysis has been performed.

•The randomization will be concealed by using sequentially numbered identical appearing containers of probiotics and placebo group

•All the patients will receive single visit full mouth debridement using ultrasonic scaler and Gracey curettes.

•Instructions for maintaining adequate plaque control and oral hygiene instructions will be given. Also, the patients will be instructed not to use any other mechanical or chemical plaque agent during the study period.

•Then the patients will be supplied with Bacillus coagulans probiotic,  Streptococcus salivarius probiotic and placebo tablets to be taken once daily 1 hour after dinner for 1 month.

•Patients will be instructed to chew the tablet for 1 minute, swish it around the mouth and then swallow.

•Clinical parameters will be recorded again at 1 month and 3 months recall visits.

•The assessment of clinical parameter at baseline, 1month, and 3months will be carried out by an independent examiner who is blinded about the treatment groups.

IMMUNOLOGICAL ASSESSMENT:

•Salivary IL-6 will be estimated using commercially available ELISA kit.

•5ml of unstimulated saliva samples will be collected from each patient. Saliva will be collected between 9-11 am in all the patients to avoid diurnal variation prior to subgingival plaque collection and clinical parameter recording to avoid contamination of the samples with blood.

•All patients will be asked to avoid food consumption for at least 1 hour before saliva collection. Patient will be seated on a dental chair and saliva will be collected over 5 min period with instructions to pool saliva in the floor of the mouth and passively drool it into a sterile container.

•Collected sample will be centrifuged at 5000 rpm for 10 minutes.

•Supernatant will be immediately transferred to a sterile plastic vial and stored at -80°C and later will be send to laboratory for further processing.

MICROBIOLOGICAL ASSESSMENT:

•A site with deepest probing pocket depth will be selected for microbial sampling from every participant at baseline, 1month and 3months.

•Subgingival plaque samples will be collected using sterilized curette and then suspended in 1ml normal saline solution and will be subjected to evaluation using Real Time Polymerase chain reaction for P gingivalis, B. coagulans & Streptococcus salivarius