periodontal disease and caries are the most prevalent infectious oral diseases in human , where both are associated with dental plaque.[13 ] the removal of plaque is the main key of prevention and the first step in treatment of periodontal disease . there are physical and chemical approaches for controlling the plaque where the former is more common and cost - effective but because of its dependence to individuals hand skill it can not be reliable all the time , so the use of chemical methods as a complementary way has been demonstrated to meet the adequate plaque control . numerous chemical agents have been developed so far , chlorhexidine ( chx ) as a gold standard appears to be the most effective antimicrobial agent for reduction of both plaque and gingivitis.[49 ] its effectiveness can be attributed to it bactericidal and bacteriostatic effects and its substantivity within the oral cavity ( 8 h after rinsing).[1013 ] however , the adverse - effects of chx limit the long - term use of this antiseptic agent and include taste alteration , excess formation of supragingival calculus , soft - tissue lesions in young patients , allergic responses , and staining of teeth and soft tissues . this kind of discoloration especially in the interproximal areas , and tongue are often caused by a precipitation reaction between tooth - bound chlorhexidine and chromogens from food or beverages . in a clinical - trial study conducted by grgan et al . in 2006 , the change in color of the labial and buccal mucosa , particularly of the gingiva , after day 3 of rinsing was reported as the most commonly side effect of 0.2% alcohol - free chlorhexidine mouthrinse . a number of chlorhexidine mouthrinse products are available worldwide at concentrations between 0.1% to 0.2% ; it has been shown that plaque inhibition by chlorhexidine is dose dependant ; lower concentrations were found to lack plaque inhibitory properties . although there are evidences that chx is an effective antimicrobial agent in both concentrations , comparison of the two existing formulations is still necessary to detect the most efficient concentration that has the least side - effects . the aim of this study was to compare the efficacy of two concentrations of chlorhexidine solutions ( 0.12% and 0.20% ) on gingival indices and the level of dental staining during 14 days . in this double - blind controlled clinical trial study 60 patients aged 1756 years were randomly selected from whom referred to periodontology department of dental clinic of mashad university . to be included in the study patients should have gingivitis and bleeding on probing but no attachment loss or bone loss . patients with previous or present history of periodontitis , those who were under medicine which could induce gingival overgrowth in the 60 days previous to the experiment , pregnant women , drug addicted , or any systemic condition that could negatively influence oral health have been excluded from the study . in the beginning of experimental period all participants have signed the written informed consents and then were taken under an oral examination which in through the following clinical parameters was recorded : 
 plaque index ( silness and le)gingival index ( le and silness)bleeding index ( ainamo and bay)stain index ( lobene ) 
  plaque index ( silness and le ) gingival index ( le and silness ) bleeding index ( ainamo and bay ) after that a coded bottle of mouthwash was given to each patient by a nurse who was not informed about the meaning of each code either . these bottles could contain 0.12% chx , 0.2% chx or placebo ( 20 bottles of each ) . patients were asked to rinse their mouthwash twice daily after brushing for 2 weeks . in the day 14 all the mentioned clinical parameters were re - assessed by one trained experienced examiner under standard dental office and light source conditions . the data were entered into a computer using the statistical package for social science ( spss 15.5 ) software and analyzed by  mann - whitney  test and p value was 0.05 . table 1 shows the results concerning clinical parameters . the mean difference of plaque index before and after the examination period for both groups rinsed chx ( 0.2% or 0.12% ) was statistically higher than the placebo group ( p < 0.0001 for both chx groups ) . similar effects were found for gingival index , however , no statistically significant differences were observed between both chlorhexidine concentration regimes ( p = 0.552 ) ( mann  whitney test ) . mean differences of pi , gi , gbl of two chx concentration and the placebo group for gingival bleeding index , the mean difference of the group that rinsed 0.2% chx was 24.157 that is significantly higher than 0.12% chx group ( 13.672 ) and placebo group ( 0.020 ) ( p < 0.0001 ) . the amount of gingival bleeding reduction in group used 0.12% chx was also significantly more than the control group ( p < 0.0001 ) . results showed that after 14 days taking chx the dental staining area and intensity increased significantly in comparison with the placebo group ) ( p < 0.0001 ) . significance difference was seen between 2 chx concentration so that the 0.2% chx caused much more staining on the teeth than 0.12% chx ( p = 0.001 ) [ figures 1 and 2 ] . after 14 days ( mann - whitney test , p = 0.00 < 0.05 ,  = 30.28 ) mean difference of stain  intensity  after 14 days ( mann - whitney test , p = 0.00 < 0.05 ,  = 32.67 ) this study evaluated clinically two chlorhexidine concentration regimes as adjuncts to mechanical plaque control . a randomized , cross - over , double blind design was chosen in order to generate the best possible evidence . in this study , there were found no significant differences between 0.2% and 0.12% chx mouth rinses in term of pi and gi that is similar to the results of previous studies . franco et al . reported no remarked differences between both concentrations in relation to plaque and gingival bleeding . quirynen et al . demonstrated that the chx 0.12% and the chx 0.12% + cpc 0.05% formulations were as efficient as the chx 0.2% mouthrinse in retarding de novo plaque formation . however , in a more different study stoeken et al . did not see 0.12% chx as effective as 0.2% , most likely it 's due to forms of chx they used in their experiments as 0.2% chx was applied in form of mouthrinse and 0.12% chx as a spray . lang et al . showed that gingivitis can be controlled successfully on a longitudinal basis using 0.1% or 0 . 2% mouthrinses of chx as an adjunct to daily toothbrushing . in our study , gbi found to be decreased significantly more by chx 0.2% than 0.12% chx that is not totally supported by the results of franco et al . the difference in terms of gingival bleeding from these studies and the present may be due to the different design of the studies . as in franco 's study participants were submitted to professional mechanical tooth cleaning and received oral hygiene instruction at the beginning of the experiment , while in our study all participants had gingivitis at the baseline . in term of dental staining index , clinical studies of the influence of chlorhexidine concentration on staining are few , not well controlled and contradictory . . obtained similar results to our study so that the lower concentrations of chx induce significantly less dental staining . reported the 0.12% chlorhexidine + fluoride products have less propensity to induce dietary staining although it appeared to cause some loss of efficacy . on observed that the optical density readings for specimens treated with saliva and the 0.12% chlorhexidine formulation were at most passages slightly higher than with the 0.2% formulation . the results of this study may contribute to the clinical practice in this way that the lower concentrations of chx should be prescribed , decreasing side effects , since higher concentrations do not seem to be more effective in controlling dental plaque and gingivitis . based on the results of this study , we can conclude that the lower concentrations of chx should be prescribed , decreasing side effects , since higher concentrations do not seem to be more effective in controlling dental plaque and gingivitis .
background : chlorhexidine ( chx ) as a gold standard chemical agent appears to be the most effective antimicrobial agent for reduction of both plaque and gingivitis . 
 the aim of this study was to compare the efficacy of two concentrations of digluconate chlorhexidine ( chx ) solutions ( 0.12% and 0.20% ) on gingival indices and the level of dental staining during 14 days.materials and methods : in this double - blind controlled clinical trial study 60 patients with moderate to severe gingivitis aged 1756 years were randomly selected and divided to three groups : group i ( placebo ) group ii ( 0.12% chx ) , and group iii ( 0.2% chx ) . 
 patients rinsed their mouthwashes twice a day after brushing . before the examination and after 14 days plaque index , gingival index , bleeding index , and stain index were evaluated . 
 the data were analyzed by 
 mann 
 whitney 
 test and p value was 0.05.results:the results showed that plaque index and gingival index significantly reduced in groups ii and iii in comparison with the placebo group ( p < 0.0001 ) . 
 however , the two concentrations did not differ significantly from each other ( p = 0.552 ) . 
 same results were observed in term of gingival bleeding index with this different that 0.2% chx was significantly more efficient than 0.12% chx ( p < 0.0001 ) . 
 chx mouthrinse , both concentrations , significantly increased the dental staining level ( intensity and area ) in comparison with the placebo group . 
 remarkable difference also was seen between 2 chx concentrations so that the 0.2% chx caused much more staining on the teeth than 0.12% chx.conclusion:based on the results of this study we can conclude that the lower concentrations of chx should be prescribed , decreasing side effects , since higher concentrations do not seem to be more effective in controlling dental plaque and gingivitis .