In this study,tabriz dental students who are volunteer to cooperate in the above project are participared.sixteen participants will be studied.first of all,two mouth washes labeled A,B are given to them.they will be asked to use them five days,twice a day after eating. Respectively,they will be asked to gargle A mouth wash(chlorhexidine)and after a minute B mouth wash(listerine) during one minute.in this time,participants should not use mechanical means of plaque control such as tooth brush and floss.at the end of the period,participants will be checked-up from the point of the plaque index and bleeding during probing.after measuring the above indicators,participants will be brushing and they recommended to visit after four days and to be checked up from the point of the absence of plaque and will be ready for the second stage.In the second stage,first B mouth wash(listerine) is used and after a minute,A mouth wash(chlorhexidine)is used for a minute twice a day.after 5 days,again plaque index and bleeding on the probing is recorded and members will be ready for the third stage.
In the third stage,B mouth wash(listerine) is only used and after wash out period,they will be prepared for the fourth period. Similarly,the fourth stage will be done with difference of using only A mouth wash(chlorhexidine)in this stage.