human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: This study evaluated the effect of 2 % chlorhexidine ( CHX ) pretreatment of dentin on the immediate and aged microtensile bond strength ( μTBS ) of different adhesives to dentin in vivo and in vitro . Class I cavities were prepared in 80 caries-free human third molars of 40 patients in a split-mouth fashion . In each tooth pair , one tooth received 2 % CHX pretreatment after which both teeth were r and omly assigned to one of the following groups with respect to the type of adhesive system applied : Adper Single Bond 2 ( etch- and -rinse ) , Clearfil SE Bond ( two-step self-etch ) , Clearfil S(3 ) Bond ( one-step self-etch ) , and Adper Prompt-L-Pop ( all-in-one self-etch ) . The teeth were restored with resin composite and extracted for μTBS testing either immediately or after six months in function . In vitro specimen pairs were prepared as with the clinical protocol in intact , freshly extracted human molars , and thereafter , subjected to testing immediately or after 5000 × thermocycling . Data were analyzed with four-way analysis of variance ( ANOVA ) . Bonferroni test was utilized for pair-wise comparisons . The immediate bond strength values were significantly higher than " aged " ones for all tested adhesives ( p=0.00 ) . The in vitro immediate bond strength values were statistically higher than in vivo bond strength values ( p<0.05 ) . While the bond strength of in vitro aged , CHX-treated sample s were higher than their in vivo counterparts ( p<0.05 ) , no difference was observed in non-CHX treated groups ( p>0.05 ) . In the absence of CHX pretreatment , all adhesives showed significantly higher immediate bond strength values than CHX-treated groups , while all " aged " , non-pretreated adhesives exhibited significantly lower bond strength values ( both p<0.05 ) . By contrast , chlorhexidine pretreatment result ed in significantly higher aged bond strengths , regardless of the adhesive system and testing condition . Aging-associated decline in dentin bond strength of etch- and rinse and self-etch adhesives can be counteracted by chlorhexidine application The purpose of this study was to investigate the influence of chlorhexidine ( CHX ) concentration on the microtensile bond strength ( muTBS ) of contemporary adhesive systems . Eighty bovine central incisors were used in this study . The facial enamel surface of the crowns was abraded with 600-grit silicon carbide paper to expose flat , mid-coronal dentin surfaces . The tested material s were Scotchbond Multi purpose ( SMP ) , Single-Bond ( SB ) , Clearfil SE Bond ( CSEB ) and Clearfil Tri S Bond ( CTSB ) . All the material s were applied according to manufacturer 's instructions and followed by composite application ( Z250 ) . The teeth were r and omly divided into 16 groups : for the etch- and -rinse adhesives ( SMP and SB ) , 0.12 % or 2 % CHX was applied prior to or after the acid etching procedure . For the self-etch adhesives ( CSEB and CTSB ) 0.12 % or 2 % CHX was applied prior to the primer . Control groups for each one of the adhesive systems were also set up . The specimens were immediately su bmi tted to muTBS testing and the data were analyzed using Analysis of Variance and the Tukey post hoc test ( alpha = .01 ) . The failure patterns of the specimens were observed using scanning electron microscopy . The effects of 2 % CHX were statistically significant ( p < 0.01 ) for the self-etch adhesives but were not significant for the etch- and -rinse adhesive systems . Analysis of the data demonstrated no statistical difference between the etch- and -rinse adhesive systems . CHX-based cavity disinfectants in concentrations higher than 0.12 % should be avoided prior to the self-etch adhesive systems evaluated in this study to diminish the possibilities of reduction in bond strength PURPOSE To evaluate the effect of 2 % chlorhexidine on the microtensile bond strength of composite resin to dentin treated with three dentin bonding systems . MATERIAL S AND METHODS Flat dentinal surfaces were prepared in 24 extracted human third molars . Teeth were r and omly divided into 8 distinct experimental groups according to the adhesive applied ( Prime & Bond NT , Single Bond and Clearfil SE Bond ) , the application ( yes/no ) of chlorhexidine , and the time point at which it was applied ( before or after acid etching the dentin ) . Composite resin blocks were built up over treated surfaces , and teeth were then stored in water at 37 degrees C for 24 h. Sample s were thermocycled , stored under the same conditions , and then vertically sectioned , thus obtaining specimens with 1.0 + /- 0.1 mm2 cross-sectional area . Specimens were stressed in tension at 0.5 mm/min crosshead speed . Bond strength results were evaluated using a one-way ANOVA ( p < 0.05 ) . The modes of failures were verified using optical microscopy . Dentin disks were obtained from 3 additional teeth treated in the same manner for observation under SEM . The most representative sample s of fractured specimens were also observed under SEM . RESULTS No statistically significant differences of bond strength values were found between any groups . Failures occurred mainly within the bond ; exclusively adhesive fractures ( adhesive-dentin ) were not observed . CONCLUSION The 2 % chlorhexidine solution , applied before or after acid etching of the dentin , did not interfere with the microtensile bond strength of composite resin to the dentin treated with Prime & Bond NT , Single Bond , or Clearfil SE Bond bonding systems Incompletely infiltrated collagen fibrils in acid-etched dentin are susceptible to degradation . We hypothesize that degradation can occur in the absence of bacteria . Partially demineralized collagen matrices ( DCMs ) prepared from human dentin were stored in artificial saliva . Control specimens were stored in artificial saliva containing proteolytic enzyme inhibitors , or pure mineral oil . We retrieved them at 24 hrs , 90 and 250 days to examine the extent of degradation of DCM . In the 24-hour experimental and 90- and 250-day control specimens , we observed 5- to 6-μm-thick layers of DCM containing b and ed collagen fibrils . DCMs were almost completely destroyed in the 250-day experimental specimens , but not when incubated with enzyme inhibitors or mineral oil . Functional enzyme analysis of dentin powder revealed low levels of collagenolytic activity that was inhibited by protease inhibitors or 0.2 % chlorhexidine . We hypothesize that collagen degradation occurred over time , via host-derived matrix metalloproteinases that are released slowly over time Dentine rods measuring approx . 0.7 x 0.7 x 5.0 mm were prepared from the crowns of extracted human third molars . The specimens were demineralized in 0.5 M EDTA ( pH 7.0 ) for 3 days and their volume measured with a digital micrometer under a dissecting microscope . The specimens were r and omly assigned to experimental groups and were chemically dehydrated in acetone . Next they were dried using either hexamethyldisilazane , Peldri II , or critical-point drying techniques . The dimensions of the specimens were measured again after each step and the changes in volume were expressed as a percentage of the original demineralized volume . The effects of fixing the specimens in 10 % buffered formalin before dehydration with acetone were also investigated for every drying procedure . Dehydration in acetone caused a small but significant reduction in the volume of demineralized formalin-fixed specimens but unfixed specimens did not change significantly . In general , all three drying procedures caused some shrinkage in demineralized dentine specimens . Unfixed specimens exhibited a volumetric shrinkage of approx . 15 - 20 % after drying with any of the methods . Fixed specimens shrank more than unfixed specimens after drying ( 25 - 35 % ) . Regardless of the drying technique , the specimens shrank a further 10 - 20 % when measured in the vacuum chamber of the scanning electron microscope . Among the three drying techniques employed , hexamethyldisilazane seems to be a very useful alternative to critical-point drying for the preparation of dentine specimens for scanning electron microscopy OBJECTIVES To examine the effect of adjunctive application of chlorhexidine ( CHX ) and ethanol-wet bonding ( EWB ) on bond durability and nanoleakage of hydrophobic adhesive to sound ( SD ) and caries-affected dentine ( CAD ) . METHODS Dentine surfaces of molars were etched after caries removal and r and omly allocated to four groups ( n=12 ) . In Groups 1 and 2 , dentine surfaces were saturated with either 2 ml of 100 % ethanol or 2 ml of ethanol with 2 % CHX for 60s . In Groups 3 and 4 , dentine surfaces were saturated with either 15 μL of distilled water or 15 μL of distilled water with 2 % CHX for 60s . Two coats of primer , followed by neat resin were applied and light-cured for 40s . Resin composite build-ups were placed and bonded specimens were sectioned for bond strength testing after 24 h and 12 months ' storage in artificial saliva . Bond strength data were analyzed using 3-way ANOVA and SNK tests . Interfacial nanoleakage was evaluated after 24 h and 12 months using a field-emission scanning electron microscopy and data were analyzed using Kruskal-Wallis test . RESULTS Significant differences were observed for the three factors : " substrate " ( p<0.001 ) , " rewetting agents " ( p<0.001 ) and " time " ( p<0.001 ) on bond strength . Incorporation of 2 % CHX to EWB preserved bond strength to SD and CAD and reduced interfacial nanoleakage after 12 months . Incorporation of 2 % CHX to WWB also preserved bond strength to SD after ageing . CONCLUSIONS Incorporation of chlorhexidine to ethanol-wet bonding has an interaction effect on preservation of bond durability to sound and caries-affected dentine . CLINICAL SIGNIFICANCE Incorporation of chlorhexidine to ethanol-wet bonding with hydrophobic adhesive enhances the success rate of aesthetic bonded restorations Background The effect of chlorhexidine on bond durability of universal adhesives is not clear . The aim of this study was to evaluate the effect of chlorhexidine on 6-month water storage bond strength of adhesive systems . Material and Methods 72 freshly sound human extracted molars were selected . In each tooth both buccal and lingual sides were prepared by bur to reach superficial dentin and r and omly divided into 6 groups and 12 sub-groups and bonded with Scotchbond Universal ( SBU ) or Scotchbond Multi- purpose ( SBMP ) with/without chlorhexidine ( CHX ) usage . Group 1 : SBU , group2 : SBU+CHX , group3 : Etch+SBU , group4 : Etch+CHX+SBU , group5 : Etch+SBMP , group6 : Etch+CHX+SBMP . After composite curing , water storage and thermocycling was done . Each group was divided into two subgroups . One was tested immediately , and the other was thermocycled for 5000 cycles ( 5 - 55 ° C ) ( it was equivalent to 6 months of storage in distilled water ) . Shear bond strength test was done and failure modes were determined by Stereomicroscope . The data were analyzed by one-way ANOVA , Tukey post-hoc test and Paired Two test with P<0.050 as the level of significance . Results Shear bond strength in late SBU ( Self etch ) was significantly lower than late SBU [ Etch and rinse ( ER ) ] , P value= 0.0001 , also shear bond strength in late SBU [ self-etch ( SE ) ] was significantly lower than immediate SBU ( SE ) , P value= 0.01 . There were no significant differences between other sub-groups and conditions . The most failure mode was adhesive in all the groups . Conclusions Long term bonding durability of SBU(ER ) was better than SBU ( SE ) . CHX usage had prevented bond strength decrease in SBU and SBMP in long term . CHX usage did not have any effect on immediate shear bond strength of SBU and SBMP . Immediate and late shear bond strength of SBMP with/without CHX usage was similar to SBU(SE , ER ) . Key words : Dentin Bonding , Shear Bond Strength , chlorhexidine , 6-month storage STATEMENT OF THE PROBLEM With Institutional Review Board approval , 39 patients who needed restoration of noncarious cervical lesions ( NCCLs ) were enrolled in this study . A total of 125 NCCLs were selected and r and omly assigned to four groups : 1 ) a three-step etch- and -rinse adhesive , Adper Scotchbond Multi- Purpose ( MP , 3 M ESPE , St Paul , MN , USA ) ; 2 ) a two-step etch- and -rinse adhesive , Adper Single Bond Plus ( SB , 3 M ESPE ) ; 3 ) a two-step self-etch adhesive , Adper Scotchbond SE ( SE , 3 M ESPE ) ; and 4 ) a one-step self-etch adhesive , Adper Easy Bond ( EB , 3 M ESPE ) . A nanofilled 
    Output:
    
agent
Conclusions : The application of a 2 % chlorhexidine solution after acid etching increased the microtensile bond strength significantly for follow-up times of 6 months or more .
The adhesive type had no influence
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: This study evaluated the effect of 2 % chlorhexidine ( CHX ) pretreatment of dentin on the immediate and aged microtensile bond strength ( μTBS ) of different adhesives to dentin in vivo and in vitro . Class I cavities were prepared in 80 caries-free human third molars of 40 patients in a split-mouth fashion . In each tooth pair , one tooth received 2 % CHX pretreatment after which both teeth were r and omly assigned to one of the following groups with respect to the type of adhesive system applied : Adper Single Bond 2 ( etch- and -rinse ) , Clearfil SE Bond ( two-step self-etch ) , Clearfil S(3 ) Bond ( one-step self-etch ) , and Adper Prompt-L-Pop ( all-in-one self-etch ) . The teeth were restored with resin composite and extracted for μTBS testing either immediately or after six months in function . In vitro specimen pairs were prepared as with the clinical protocol in intact , freshly extracted human molars , and thereafter , subjected to testing immediately or after 5000 × thermocycling . Data were analyzed with four-way analysis of variance ( ANOVA ) . Bonferroni test was utilized for pair-wise comparisons . The immediate bond strength values were significantly higher than " aged " ones for all tested adhesives ( p=0.00 ) . The in vitro immediate bond strength values were statistically higher than in vivo bond strength values ( p<0.05 ) . While the bond strength of in vitro aged , CHX-treated sample s were higher than their in vivo counterparts ( p<0.05 ) , no difference was observed in non-CHX treated groups ( p>0.05 ) . In the absence of CHX pretreatment , all adhesives showed significantly higher immediate bond strength values than CHX-treated groups , while all " aged " , non-pretreated adhesives exhibited significantly lower bond strength values ( both p<0.05 ) . By contrast , chlorhexidine pretreatment result ed in significantly higher aged bond strengths , regardless of the adhesive system and testing condition . Aging-associated decline in dentin bond strength of etch- and rinse and self-etch adhesives can be counteracted by chlorhexidine application The purpose of this study was to investigate the influence of chlorhexidine ( CHX ) concentration on the microtensile bond strength ( muTBS ) of contemporary adhesive systems . Eighty bovine central incisors were used in this study . The facial enamel surface of the crowns was abraded with 600-grit silicon carbide paper to expose flat , mid-coronal dentin surfaces . The tested material s were Scotchbond Multi purpose ( SMP ) , Single-Bond ( SB ) , Clearfil SE Bond ( CSEB ) and Clearfil Tri S Bond ( CTSB ) . All the material s were applied according to manufacturer 's instructions and followed by composite application ( Z250 ) . The teeth were r and omly divided into 16 groups : for the etch- and -rinse adhesives ( SMP and SB ) , 0.12 % or 2 % CHX was applied prior to or after the acid etching procedure . For the self-etch adhesives ( CSEB and CTSB ) 0.12 % or 2 % CHX was applied prior to the primer . Control groups for each one of the adhesive systems were also set up . The specimens were immediately su bmi tted to muTBS testing and the data were analyzed using Analysis of Variance and the Tukey post hoc test ( alpha = .01 ) . The failure patterns of the specimens were observed using scanning electron microscopy . The effects of 2 % CHX were statistically significant ( p < 0.01 ) for the self-etch adhesives but were not significant for the etch- and -rinse adhesive systems . Analysis of the data demonstrated no statistical difference between the etch- and -rinse adhesive systems . CHX-based cavity disinfectants in concentrations higher than 0.12 % should be avoided prior to the self-etch adhesive systems evaluated in this study to diminish the possibilities of reduction in bond strength PURPOSE To evaluate the effect of 2 % chlorhexidine on the microtensile bond strength of composite resin to dentin treated with three dentin bonding systems . MATERIAL S AND METHODS Flat dentinal surfaces were prepared in 24 extracted human third molars . Teeth were r and omly divided into 8 distinct experimental groups according to the adhesive applied ( Prime & Bond NT , Single Bond and Clearfil SE Bond ) , the application ( yes/no ) of chlorhexidine , and the time point at which it was applied ( before or after acid etching the dentin ) . Composite resin blocks were built up over treated surfaces , and teeth were then stored in water at 37 degrees C for 24 h. Sample s were thermocycled , stored under the same conditions , and then vertically sectioned , thus obtaining specimens with 1.0 + /- 0.1 mm2 cross-sectional area . Specimens were stressed in tension at 0.5 mm/min crosshead speed . Bond strength results were evaluated using a one-way ANOVA ( p < 0.05 ) . The modes of failures were verified using optical microscopy . Dentin disks were obtained from 3 additional teeth treated in the same manner for observation under SEM . The most representative sample s of fractured specimens were also observed under SEM . RESULTS No statistically significant differences of bond strength values were found between any groups . Failures occurred mainly within the bond ; exclusively adhesive fractures ( adhesive-dentin ) were not observed . CONCLUSION The 2 % chlorhexidine solution , applied before or after acid etching of the dentin , did not interfere with the microtensile bond strength of composite resin to the dentin treated with Prime & Bond NT , Single Bond , or Clearfil SE Bond bonding systems Incompletely infiltrated collagen fibrils in acid-etched dentin are susceptible to degradation . We hypothesize that degradation can occur in the absence of bacteria . Partially demineralized collagen matrices ( DCMs ) prepared from human dentin were stored in artificial saliva . Control specimens were stored in artificial saliva containing proteolytic enzyme inhibitors , or pure mineral oil . We retrieved them at 24 hrs , 90 and 250 days to examine the extent of degradation of DCM . In the 24-hour experimental and 90- and 250-day control specimens , we observed 5- to 6-μm-thick layers of DCM containing b and ed collagen fibrils . DCMs were almost completely destroyed in the 250-day experimental specimens , but not when incubated with enzyme inhibitors or mineral oil . Functional enzyme analysis of dentin powder revealed low levels of collagenolytic activity that was inhibited by protease inhibitors or 0.2 % chlorhexidine . We hypothesize that collagen degradation occurred over time , via host-derived matrix metalloproteinases that are released slowly over time Dentine rods measuring approx . 0.7 x 0.7 x 5.0 mm were prepared from the crowns of extracted human third molars . The specimens were demineralized in 0.5 M EDTA ( pH 7.0 ) for 3 days and their volume measured with a digital micrometer under a dissecting microscope . The specimens were r and omly assigned to experimental groups and were chemically dehydrated in acetone . Next they were dried using either hexamethyldisilazane , Peldri II , or critical-point drying techniques . The dimensions of the specimens were measured again after each step and the changes in volume were expressed as a percentage of the original demineralized volume . The effects of fixing the specimens in 10 % buffered formalin before dehydration with acetone were also investigated for every drying procedure . Dehydration in acetone caused a small but significant reduction in the volume of demineralized formalin-fixed specimens but unfixed specimens did not change significantly . In general , all three drying procedures caused some shrinkage in demineralized dentine specimens . Unfixed specimens exhibited a volumetric shrinkage of approx . 15 - 20 % after drying with any of the methods . Fixed specimens shrank more than unfixed specimens after drying ( 25 - 35 % ) . Regardless of the drying technique , the specimens shrank a further 10 - 20 % when measured in the vacuum chamber of the scanning electron microscope . Among the three drying techniques employed , hexamethyldisilazane seems to be a very useful alternative to critical-point drying for the preparation of dentine specimens for scanning electron microscopy OBJECTIVES To examine the effect of adjunctive application of chlorhexidine ( CHX ) and ethanol-wet bonding ( EWB ) on bond durability and nanoleakage of hydrophobic adhesive to sound ( SD ) and caries-affected dentine ( CAD ) . METHODS Dentine surfaces of molars were etched after caries removal and r and omly allocated to four groups ( n=12 ) . In Groups 1 and 2 , dentine surfaces were saturated with either 2 ml of 100 % ethanol or 2 ml of ethanol with 2 % CHX for 60s . In Groups 3 and 4 , dentine surfaces were saturated with either 15 μL of distilled water or 15 μL of distilled water with 2 % CHX for 60s . Two coats of primer , followed by neat resin were applied and light-cured for 40s . Resin composite build-ups were placed and bonded specimens were sectioned for bond strength testing after 24 h and 12 months ' storage in artificial saliva . Bond strength data were analyzed using 3-way ANOVA and SNK tests . Interfacial nanoleakage was evaluated after 24 h and 12 months using a field-emission scanning electron microscopy and data were analyzed using Kruskal-Wallis test . RESULTS Significant differences were observed for the three factors : " substrate " ( p<0.001 ) , " rewetting agents " ( p<0.001 ) and " time " ( p<0.001 ) on bond strength . Incorporation of 2 % CHX to EWB preserved bond strength to SD and CAD and reduced interfacial nanoleakage after 12 months . Incorporation of 2 % CHX to WWB also preserved bond strength to SD after ageing . CONCLUSIONS Incorporation of chlorhexidine to ethanol-wet bonding has an interaction effect on preservation of bond durability to sound and caries-affected dentine . CLINICAL SIGNIFICANCE Incorporation of chlorhexidine to ethanol-wet bonding with hydrophobic adhesive enhances the success rate of aesthetic bonded restorations Background The effect of chlorhexidine on bond durability of universal adhesives is not clear . The aim of this study was to evaluate the effect of chlorhexidine on 6-month water storage bond strength of adhesive systems . Material and Methods 72 freshly sound human extracted molars were selected . In each tooth both buccal and lingual sides were prepared by bur to reach superficial dentin and r and omly divided into 6 groups and 12 sub-groups and bonded with Scotchbond Universal ( SBU ) or Scotchbond Multi- purpose ( SBMP ) with/without chlorhexidine ( CHX ) usage . Group 1 : SBU , group2 : SBU+CHX , group3 : Etch+SBU , group4 : Etch+CHX+SBU , group5 : Etch+SBMP , group6 : Etch+CHX+SBMP . After composite curing , water storage and thermocycling was done . Each group was divided into two subgroups . One was tested immediately , and the other was thermocycled for 5000 cycles ( 5 - 55 ° C ) ( it was equivalent to 6 months of storage in distilled water ) . Shear bond strength test was done and failure modes were determined by Stereomicroscope . The data were analyzed by one-way ANOVA , Tukey post-hoc test and Paired Two test with P<0.050 as the level of significance . Results Shear bond strength in late SBU ( Self etch ) was significantly lower than late SBU [ Etch and rinse ( ER ) ] , P value= 0.0001 , also shear bond strength in late SBU [ self-etch ( SE ) ] was significantly lower than immediate SBU ( SE ) , P value= 0.01 . There were no significant differences between other sub-groups and conditions . The most failure mode was adhesive in all the groups . Conclusions Long term bonding durability of SBU(ER ) was better than SBU ( SE ) . CHX usage had prevented bond strength decrease in SBU and SBMP in long term . CHX usage did not have any effect on immediate shear bond strength of SBU and SBMP . Immediate and late shear bond strength of SBMP with/without CHX usage was similar to SBU(SE , ER ) . Key words : Dentin Bonding , Shear Bond Strength , chlorhexidine , 6-month storage STATEMENT OF THE PROBLEM With Institutional Review Board approval , 39 patients who needed restoration of noncarious cervical lesions ( NCCLs ) were enrolled in this study . A total of 125 NCCLs were selected and r and omly assigned to four groups : 1 ) a three-step etch- and -rinse adhesive , Adper Scotchbond Multi- Purpose ( MP , 3 M ESPE , St Paul , MN , USA ) ; 2 ) a two-step etch- and -rinse adhesive , Adper Single Bond Plus ( SB , 3 M ESPE ) ; 3 ) a two-step self-etch adhesive , Adper Scotchbond SE ( SE , 3 M ESPE ) ; and 4 ) a one-step self-etch adhesive , Adper Easy Bond ( EB , 3 M ESPE ) . A nanofilled 
    Output:
    