in every field of dentistry , awareness regarding the importance of preserving tooth tissue is becoming evident . the current odontologic era is characterized by an increasing move toward less invasive treatment and preventive dentistry . the search for a more gentle , comfortable , and conservative caries excavation has led to the development of methods which aim at providing minimal thermal changes , less vibration and pain , and removal of infected dentine only . laser , chemomechanical excavation , and air abrasion are successful in overcoming these problems . the chemomechanical caries removal ( cmcr ) technique stands out among other alternative methods as it is a nonaggresive excavation method which uses a chemical gel that is said to remove only the infected dentine where collagen is degraded , maintaining the demineralized portion that is capable of being remineralized and repaired . this approach is based on principle of minimal invasive dentistry that involves application of substances such as caridex , carisolv , papacarie , and carie - care for the removal of carious dentin . the use of carisolv introduced in the mid 90 's as a chemical agent to remove caries is broadly discussed in the dental literature . although carisolv was quite a success in the field of dentistry , certain drawbacks have also been reported which includes requirement of customized instruments , more time and its high cost - making it available for just a privileged few . in 2003 , a research project in brazil developed a papain - based gel to universalize the use of chemomechanical method , and the new formula was commercially known as papacarie . the union of these three components confers antibiotic , bacteriostatic , and anti - inflammatory properties to this agent . papain is an endoprotein from the proteolytic cysteine family that acts only upon damaged tissue , since plasma antiprotease is not present in the infected tissue , preventing papain 's proteolytic action in tissues considered normal . chloramine is a compound containing chlorine and ammonia with antibiotic and disinfecting properties , used for the irrigation of root canals . papacarie was found to be easy to manipulate , simple and cheap , as well as effective in removing infected tissues . carie - care is a more recent , minimally invasive method for chemo - mechanical dentine caries removal , developed by uni - biotech pharmaceuticals private limited , chennai , india in collaboration with vittal mallya scientific research foundation . even this is a gel - based formulation containing a purified enzyme , derived from the plant carica papaya along with the benefits of clove oil . cys-25 then performs a nucleophilic attack on carbonyl carbon which frees the amino terminal of the peptide , the enzyme is then deacylated by a water molecule and releases the carboxy terminal portion of the peptide . studies have been done using various cmcr agents namely 5% sodium hypochlorite , gk101 , caridex , carisolv and papacarie . however , there is a need to evaluate the efficacy of a more recent material like carie - care. the extent of carious dentine excavation , the time taken by each technique and even the microbiological aspect needs to be evaluated as it plays an important role in the progression of dentinal caries . hence , the present study was designed to evaluate and compare the efficacy of newer enzymatic approaches , papacarie and carie - care as cmcr agents . this in vitro study was aimed to evaluate the efficacy and effectiveness of caries removal by two cmcr agents papacarie and carie - care. the study was carried out in the department of pedodontics and preventive dentistry in association with department of oral and maxillofacial pathology , st . the response or dependent variables were time required to remove dentine measured in seconds ( efficiency ) and the detection of bacteria after carious removal and dentinal tubule destruction ( efficacy ) . materials used in the study a sample size of 30 was determined by statistician by  resource equation method  . , in which caries distribution is done according to site and stage of progression of the lesion . this concept of sites / stages ( si / sta ) replaced the classification of black and promoted a medical model of conservative dentistry in clinical practice . the extracted teeth having site 2 ( carious lesions at contact area of interproximal surfaces of the crown ) and stage 3 ( large dentin lesion with extended and frank cavitation ) carious lesion were included in the study . the exclusion criteria were deep carious lesion with pulp exposure or potential for pulp exposure [ figure 2 ] . extracted primary molars each tooth was sectioned mesiodistally in the center of the carious lesion using diamond discs mounted in a straight handpiece so that the two halves ( buccal and lingual or palatal ) had equal sized carious lesions . the two specimens obtained from each tooth were alternatively grouped into two allotting thirty specimens each to papacarie and carie - care for caries excavation so as to avoid selection bias . the caries excavation was done according to the manufacturer 's instructions . for both groups , the carious lesion was covered with gel and left undisturbed for 30 s. when the gel was cloudy , it was removed by scraping gently with the spoon excavator without application of any vertical pressure , after which some more gel was applied on the carious lesion and scraped as the gel turned cloudy and the process was continued until the gel was no longer cloudy . the gel was then rinsed and the cavity was then wiped with a moistened cotton pellet . the time taken for procedures was measured from start of caries removal till the cavity was confirmed to be free of caries with the help of a stop watch and was recorded . after caries removal , the tooth samples were decalcified in 10% formic acid at normal room temperature . [ figure 3 ] the decalcified samples were then washed in water , then the teeth were dehydrated in ascending degrees of ethanol ( 70 - 100% ) , they were then cleared in xylene and later embedded in paraffin [ figure 4 ] . during the experiment , the teeth were sectioned into 5 m thickness sections serially and were stained with eosin and hematoxylin to check for the presence of bacterial deposits microscopically and dentinal tubule destruction using conventional light microscope by a single operator to reduce bias [ figures 5 and 6 ] . decalcification of specimens specimens embedded in paraffin visible bacteria in the histological section of carie - care sample no bacteria evident in the histological section of papacarie sample the independent variable investigated in this experiment was the method of carious dentine removal . the response or dependent variables were time required to remove dentine measured in seconds ( efficiency ) and the detection of bacteria after carious removal and dentinal tubule destruction ( efficacy ) . a sample size of 30 was determined by statistician by  resource equation method  . , in which caries distribution is done according to site and stage of progression of the lesion . this concept of sites / stages ( si / sta ) replaced the classification of black and promoted a medical model of conservative dentistry in clinical practice . the extracted teeth having site 2 ( carious lesions at contact area of interproximal surfaces of the crown ) and stage 3 ( large dentin lesion with extended and frank cavitation ) carious lesion were included in the study . the exclusion criteria were deep carious lesion with pulp exposure or potential for pulp exposure [ figure 2 ] . each tooth was sectioned mesiodistally in the center of the carious lesion using diamond discs mounted in a straight handpiece so that the two halves ( buccal and lingual or palatal ) had equal sized carious lesions . the two specimens obtained from each tooth were alternatively grouped into two allotting thirty specimens each to papacarie and carie - care for caries excavation so as to avoid selection bias . the caries excavation was done according to the manufacturer 's instructions . for both groups , the carious lesion was covered with gel and left undisturbed for 30 s. when the gel was cloudy , it was removed by scraping gently with the spoon excavator without application of any vertical pressure , after which some more gel was applied on the carious lesion and scraped as the gel turned cloudy and the process was continued until the gel was no longer cloudy . the gel was then rinsed and the cavity was then wiped with a moistened cotton pellet . the time taken for procedures was measured from start of caries removal till the cavity was confirmed to be free of caries with the help of a stop watch and was recorded . after caries removal , the tooth samples were decalcified in 10% formic acid at normal room temperature . [ figure 3 ] the decalcified samples were then washed in water , then the teeth were dehydrated in ascending degrees of ethanol ( 70 - 100% ) , they were then cleared in xylene and later embedded in paraffin [ figure 4 ] . during the experiment , the teeth were sectioned into 5 m thickness sections serially and were stained with eosin and hematoxylin to check for the presence of bacterial deposits microscopically and dentinal tubule destruction using conventional light microscope by a single operator to reduce bias [ figures 5 and 6 ] . decalcification of specimens specimens embedded in paraffin visible bacteria in the histological section of carie - care sample no bacteria evident in the histological section of papacarie sample the mean time taken for complete caries removal was 385.8 s for papacarie and 427.13 s for carie - care , which is slightly more . paired t - test showed significant difference between the mean time taken for caries removal for both the groups [ table 1 ] . comparison of time taken in seconds between inter - comparative groups there is no significant dentinal tubule destruction between papacarie and carie - care groups , thus indicating both are conservative [ table 2 ] . comparison of both groups with respect to dentinal tubule destruction carie - care group showed more amount of bacterial emanents when compared with papacarie . fischer 's exact test showed significant results with carie - care group containing more amount of bacterial remnants following caries excavation [ table 3 ] . although the use of burs in both high speed and low - speed handpieces for caries removal conventionally allows faster treatment , they may remove sound tooth structure as well , which may weaken the remaining tooth structure , as well as cause pulpal trauma . philosophies of dental treatment change with time and now there is more than ample evidence provided by research for a reappraisal of the traditional approaches to caries treatment . the chemo - mechanical caries removal technique has generated great interest among dental researchers due to its concept of saving unaffected tooth structure while guaranteeing the removal of the denatured collagen stage of carious dentine . although the two layers of infected and affected dentine can be differentiated by fuschin staining , the removal of infected dentin is operator and technique sensitive method . similarly , the caries detector dyes can not specify correctly dentine removal in the cavity preparations on the pulpal surface of deep cavities and at the amelo - dentinal junction . further , in this present era of esthetic and adhesive dentistry , any remaining color or stain is unacceptable . thus , the best alternative is preserving remineralizable tissue and prevention of overexcavation of the cavity . there is also a need to evaluate and compare the antimicrobial efficacy and efficiency in caries removal of these newer enzymatic approaches available commercially such as papacarie and carie - care. the present in vitro study was conducted with the objective to evaluate the efficacy ( bacterial remnants and dentinal tubule destruction ) and efficiency ( time taken ) of caries removal using papacarie and carie - care. the extracted teeth were selected based on the modified classification of mount and hume , which help determine the type of treatment ( prevention , healing , re - mineralisation , or invasive intervention ) , and assist clinicians in selecting appropriate restorative materials . carious teeth with site 2 and stage 3 lesion were included as cmcr agents can dissolve only dentinal caries structure . the selection bias was avoided by excavating the corresponding cavity halves as this minimizes differences in the excavation results due to variations in the extension , depth , localization , and structure of the caries lesion . as microflora is one of the main etiological factors in caries occurrence , it is essential to reduce the microbial counts in caries lesions . apart from this , the efficacy in caries removal is also of interest . papain , the main ingredient of papacarie , is an enzyme similar to human pepsin and has got bactericidal and bacteriostatic properities . elindt demonstrated that papain acts only on infected tissues since infected tissues lack plasmatic anti - protease called a1 antitrypsin , this is present only in sound tissues which inhibit protein digestion . the infected dentin does not contain a1 antitrypsin enzyme , so this allows partially degraded molecules to be broken by papain . carie - care , a more recent and also economical than papacarie , is a gel based formulation . clove oil is a natural analgesic and is also known to have anesthetic properties . in the present investigation , evaluations for bacterial remnants and dentinal tubule destruction were done histologically by hematoxylin and eosin staining of the sectioned samples which were decalcified in 10% formic acid . formic acid was used as it gives good results with minimal soft tissue shrinkage and minimal loss of tissue when compared with nitric acid which shows crumbling of tissue . bacteria are the most common cause of dental caries and , for this reason , it is important to eliminate the largest possible numbers of bacteria during the removal of carious tissue . in the present study , the manufacturer 's instructions were adopted , and caries removal ceased when the gel attained a clear ( nonturbid ) appearance . papacarie excavation resulted in a highly significant reduction for all tested viable bacteria when compared to carie - care. as found in this in vitro investigation , among the two agents , the time taken for caries removal by carie - care was found to be more which is 427.13 s when compared to papacarie ( 385.8 s ) . papacarie exerts an inhibitory action on cariogenic bacteria and the time taken for removal of caries was about 6 min which is in accordance with the study conducted by motta et al . in addition to papain , both papacarie and carie - care contain chloramines that are used to chemically soften the carious dentin . the chlorination affects the secondary or quarternary structure of collagen , by disrupting hydrogen bonding and thus facilitating caries removal . papacarie was found to have no ability to affect the sound collagen fibers in the inner affected and normal dentin , as papain can digest only dead cells . , who concluded that papacarie is significantly more efficient in reducing the residual cariogenic bacteria in the dentin of primary teeth when compared to carisolv . have shown clinical efficacy of caries removal is best with airotor and the microbiological efficacy ( residual cariogenic bacteria ) of caries removal was almost comparable with airotor and chemo - mechanical methods of caries removal . however , both papacarie and carie - care exhibited no dentinal tubule destruction after caries excavation which shows their minimal invasive method in preserving the underlying affected dentin for remineralization . the drawbacks of this study are this is an in vitro study , so the features such as pain during caries removal and patient 's comfort levels could not be monitored . further large - scale , well - designed randomized controlled trials are needed to substiantiate the clinical outcome of the present study . the following conclusions were drawn from the study : 
 the mean time taken for caries removal was found to be more for carie - care when compared to papacariemore amount of bacterial remnants was present after excavation with carie - careboth papacarie and carie - care were found to be conservative as no dentinal tubule destruction was evident . 
  the mean time taken for caries removal was found to be more for carie - care when compared to papacarie more amount of bacterial remnants was present after excavation with carie - care both papacarie and carie - care were found to be conservative as no dentinal tubule destruction was evident . since this is an in vitro study , the clinical significance of these findings can only be determined with further studies assessing the clinical outcome of these chemo - mechanical methods in caries excavation . within the limitations of the present study , we find the chemo - mechanical caries removal to be an adequate alternative to the conventional rotary instruments . however , the greater time requirement represents a substantial barrier to its wider use by clinicians .
aims and objectives : the chemomechanical caries removal system is made presently available containing a natural proteolytic enzyme for ease in the excavation of infected dentin . 
 the aim of the study was to evaluate the efficacy and efficiency of caries removal using papacarie and carie-care.materials and methods : a total of 30 extracted deciduous molars with proximal caries were collected , and each tooth was sectioned mesiodistally in the center of the carious lesion so that the two halves ( buccal and lingual or palatal ) have similar carious lesions , thus 30 teeth yielded 60 specimens . 
 the specimens from each tooth were divided alternatively into two groups for caries excavation either using papacarie or carie - care so as to avoid selection bias . 
 paired t - test was used to compare mean time taken for caries removal and fischer 's exact test was done for comparing bacterial remnants after caries excavation.results:mean time taken for caries removal was significantly higher for carie - care ( 427.13 s ) when compared to papacarie ( 385.8 s ) . 
 papacarie was found to be significantly more efficient in caries removal with marked reduction in the bacterial remnants following excavation . 
 however , both gels were found to be conservative as dentinal tubule destruction was not evident in either of them.conclusion:both papacarie and carie - care were found to be conservative in caries removal . 
 papacarie was more efficient in removing bacteria in lesser time from the infected carious lesion .