demands for esthetic restorations are increased . for achieving a long - term high performance composite restoration , a good isolation especially near or at the gingival margin is needed . in a situation such as sub - gingival caries , class v cavity preparation , taking impression , cementation of all - ceramic restorations with margins near the gingiva , and chronic gingival inflammation preventing or eliminating gingival bleeding or contamination by crevicular fluid is very critical for the longevity of the restoration . blood has high - protein content ( approximately 6.7% ) and fibrinogen macromolecules , on the other hand , because of protein attraction property of dentin , blood proteins can form a layer , which prevents resin infiltration into the dentin structure and reduces 30 - 70% of bond strength . in the other words , in blood contamination situation , some reactions have occurred between dentin organic layer and the blood proteins that influence resin infiltration . in recent years , use of hemostatic agents for controlling of gingival bleeding and reducing sulcular fluid are indicated . they have presented in various formulations with different mechanism of action , such as aluminum chloride , ferric sulfate compounds , iron solution , aluminum and potassium sulfate and epinephrine 0.1% . recent studies showed that most of them have acidic property ( ph = 0.7 - 3 ) and hydrophilic characteristics that can contaminate each stage of bonding procedure . by hemostatic agents application , smear layer was removed or some change in dentin surface happened that could affect the hybrid layer quality after the self - etch or etch - and - rinse adhesives usage . therefore , the efficacy of self - etch and etch - and - rinse adhesive systems should be considered first and then recommended for clinical uses . this study evaluated the shear bond strength of one etch - and - rinse and two self - etch adhesives to human dentin contaminated with a ferric sulfate hemostatic agent . the null hypothesis of this study was that contamination with ferric sulfate 20% may not have any effect on shear bond strength of etch - and - rinse and self - etch adhesive systems to dentin . in this in vitro experimental study , 60 intact caries - free human third molars were selected and cleaned up of soft tissues . then , they were stored in a 0.5% chloramine - t ( fisher chemical , fair lawn , nj , usa ) solution for 24 h. after they were rinsed , about 1.5 - 2 mm of buccal or lingual tooth structure ( enamel and dentin ) were removed by using a diamond bur ( ss white , great white series , lakewood , nj , usa ) to create flat surfaces of superficial dentin for testing ( each bur was discarded after each five preparation ) . dentin surfaces were ground with 400 and 600 grit sand paper under running water to produce a standardized smear layer . utah , usa ) was applied for 60 s and then it was rinsed for 60 s thoroughly . then dentin surfaces were etched with 37% phosphoric acid ( ivoclar / vivadent , schaan , liechtenstein ) for 10 s , were rinsed for 30 s , were blotted dried and were followed by application of one coat of tetric n - bond ( ivoclar / vivadent , schaan , liechtenstein ) for 10 s , gently air dried and were light cured for 20 s with a quartz - tungsten - halogen unit with 600 mw / cm intensity ( demetron lc , kerr , usa)group 2 : no viscostat application was done prior to etching . etching and bonding were done as in group 1group 3 : after viscostat application as in group 1 and 60 s rinsing and blot drying , primer bottle of adhese ( ivoclar / vivadent , schaan , liechtenstein ) was applied for 30 s , air drying was done and adhesive bottle of adhese was applied for 20 s , gently air dried and light cured for 20 sgroup 4 : no viscostat application was done . adhese bonding system was used same as in group 3group 5 : after viscostat application as in group 1 and 60 s rinsing and blot drying , adhese one f ( ivoclar / vivadent , schaan , liechtenstein ) was applied for 20 s , gently air dried and light cured for 20 sgroup 6 : no viscostat application was done . adhese one fadhese one fa plastic mold ( 2 mm in internal diameter and 4 mm in height ) were used to prepare the composite ( tetric n - ceram , ivoclar / vivadent , schaan , liechtenstein ) cylinders on dentin surfaces . composite were placed in two increments and each increment was light cured for 40 s. all samples were stored in distilled water for 24 h at room temperature , then were thermocycled for 500 cycles between 5c and 55c ( with a 60 s dwell time and a 15 s transfer time ) . group 1 : viscostat hemostatic agent ( ultradent product inc . , utah , usa ) was applied for 60 s and then it was rinsed for 60 s thoroughly . then dentin surfaces were etched with 37% phosphoric acid ( ivoclar / vivadent , schaan , liechtenstein ) for 10 s , were rinsed for 30 s , were blotted dried and were followed by application of one coat of tetric n - bond ( ivoclar / vivadent , schaan , liechtenstein ) for 10 s , gently air dried and were light cured for 20 s with a quartz - tungsten - halogen unit with 600 mw / cm intensity ( demetron lc , kerr , usa ) group 2 : no viscostat application was done prior to etching . etching and bonding were done as in group 1 group 3 : after viscostat application as in group 1 and 60 s rinsing and blot drying , primer bottle of adhese ( ivoclar / vivadent , schaan , liechtenstein ) was applied for 30 s , air drying was done and adhesive bottle of adhese was applied for 20 s , gently air dried and light cured for 20 s group 4 : no viscostat application was done . adhese bonding system was used same as in group 3 group 5 : after viscostat application as in group 1 and 60 s rinsing and blot drying , adhese one f ( ivoclar / vivadent , schaan , liechtenstein ) was applied for 20 s , gently air dried and light cured for 20 s group 6 : no viscostat application was done . the shear bond test was done using a universal testing machine ( m350 - 10ct testometric , lancashire , united kingdom ) at a cross head speed of 0.5 mm / min . two examiners evaluated the debonded surfaces at  40 magnifications by using a stereomicroscope ( olympus , dp 12 , germany ) to identify the mode of bond failure whether adhesive , cohesive or mixed . statistical analysis was done using one - way anova and unpaired t - test with p < 0.05 as the level of significance . mean and standard deviation values of shear bond strength test are shown in table 1 . shear bond strength data in mega pascal ( meansd ) for each tested group in comparison with case and control groups , only there was statistically significant reduction in the shear bond strength value in adhese groups ( p < 0.0001 ) . in tetric n - bond and adhese one f there was no significant reduction in shear bond strength . in comparison with viscostat applied groups , tetric n - bond had the highest ( p < 0.0001 ) and adhese one f had the lowest ( p < 0.0001 ) shear bond strength value . ferric sulfate as a hemostatic agent can coagulate collagen or plasma proteins in dentinal fluids ; changes dentinal surface structure due to its acidity and may reduce the shear bond strength . the null hypothesis was confirmed for tetric n - bond and adhese one f adhesives , which ferric sulfate 20% contamination had no effect on shear bond strength of these adhesives to dentin , significantly . phosphoric acid 37% because of its strong acidity ( ph = 0.5 ) accompany with demineralization , can eliminate surface viscostat contamination . furthermore , according to fischer 's study , phosphoric acid can decompose and destroy ferric sulfate . study showed that rinsing contaminated dentin surfaces with viscostat and viscostat plus after blood contamination did not alter shear bond strength of optibond solo plus ( kerr , orange , ca , usa ) to dentin . has shown that there were no differences in dentinal content between aluminum chloride ( a hemostatic agent ) contaminated dentin and non - contaminated one after acid etching . in adhese groups , results showed that rinsing viscostat , alone , can not eliminate surfaces contamination and thus the remnant ferric sulfate interfered with diffusion of adhese in dentinal tubules and reduce shear bond strength significantly . in a scanning electron microscope - energy dispersive x - ray spectroscopy ( sem - edx ) study by ayo - yusuf , contaminated dentinal surfaces with different hemostatic agents were studied . it was mentioned that hemostatic agents because of their acidic property ( ph = 0.7 - 3 ) , can dissolve smear layer and also obturated dentinal tubules orifices . they form an amorphous layer or a granular precipitation on the surfaces . because of the weak acidity of the primer of self - etch adhesives in comparison with phosphoric acid , it was predictable that they could not dissolve viscostat contamination so that their penetration to deeper areas of dentin was impossible . several studies emphasize that hemostatic agent can cause derangement in bonding procedure because of dentinal tubules obturation and dentinal surface was demineralized in different values . study showed that rinsing ferric sulfate and aluminum chloride hemostatic agents with water before using self - etch adhesives causes higher bond strength than non - rinsing ones . adhese one f had moderate acidity strength ( ph = 1.5 ) with 0.05  penetration depth in dentin . on the other hand , it seems that demineralized property of viscostat could be increased adhese one f dentinal diffusion depth and may be viscostat dissolved smear layer and smear plugs , which helps to better diffusion of adhese one f ( or not interfered with adhese one f diffusion ) . furthermore , in one study , it seems that despite control group that had a thick smear layer , in group with aluminum chloride hemostatic agent contamination , the smear layer was partially removed . in our study , there were significant differences between contaminated groups . according to manufacturer 's claim , viscostat is a water soluble gel and rinsing with water before bonding procedure is necessary . in etch - and - rinse adhesives because of lower ph of phosphoric acid and its capability for removing contaminants that lead to better diffusion of adhesive , the shear bond strength was higher than the others , where the demineralization effect on contaminated dentin was inhibited also , there were significant differences among control groups where tetric n - bond had the highest and adhese one f had the lowest bond strength value . phosphoric acid could cause much more microporosities in dentin than achieving better contact between adhesives and dentin substrate . removing more smear layer resulted in more mechanical retention and bond strength , which can explain the higher bond strength in tetric n - bond in comparison with adhese and adhese one f. hybrid layer in self - etch adhesives were uniform cylindrical resin tags but in etch - and - rinse adhesives were thicker with funnel - shaped resin tags . methacrylates in most of the self - etch adhesives ( such as adhese ) in acidic solutions are not stable , because of hydrolysis of ester groups that causes weaker cross - linking , an inadequate polymerization , lower bond strength and lower bonding durability . the presence of hema in adhese composition , prevents phase separation and collagen collapse in adhesive bottle and helps better adhesive diffusion unlike it can maintain water in adhesive layer and weakened mechanical strength in long - term hence to prevent this problem ,  hema free  adhesives were introduced ( such as adhese one f ) . in  hema free  adhesives , higher concentration of solvents was necessary but after solvent evaporation , homogeneity of one - step self - etch adhesives was disturbed and phase separation and water blister formation happened . these water blisters promoted to reduce hydrolytic stability of adhesive even after polymerization and bond strength reduction happened . hybrid layer in one - step and two - step self - etch adhesives were semi permeable that water can transfer through the tooth - composite interface even after polymerization . the differences in depth of penetration in dentin ( adhese : 1.2 - 2.2  , adhese one f : 0.05  ) could explain the differences of their bond strength , which resulted from this study . the presence of hydrophobic monomers and hydrophilic acids in one bottle in one - step self - etch adhesives could compromise polymerization steps and also waters in dentinal tubules , caused incomplete polymerization at the interface . all these problems can explain lower bond strength in adhese one f group in comparison with adhese and these findings were in agreement with grgoire et al . and knobloch et al . studies . in filled adhesives such as adhese and adhese one f , polymerization shrinkage reduced but because of lesser diffusion in dentin , bond strength reduced as well . according to mousavinasab and kavian study , one - bottle adhesive ( such as adhese one f ) had a very thin hybrid layer where polymerization may be damaged because of the oxygen inhibiting layer formation . some self - etch adhesives could not diffuse through smear layer because of their weak acidity in which they buffered with smear layer , enamel and dentin . buffered primer or adhesive had lower penetration . tooth demineralization with self - etch adhesives has contrary with tooth buffering capacity and these adhesives could show different behavior . adhese one f was one of the new presented products , which had an unknown behavior in adhesion . according to proena et al . study in 2009 , lower degree of conversion of self - etch adhesive and water trees builds up ( pertain to water diffusion from underlying dentin to hybrid layer ) was the main reason of lower bond strength of self - etch adhesive in comparison with etch - and - rinse adhesives . if bond strength to dentin or enamel was more than 20 mpa , mode of failure dominantly happened cohesively in tooth structure or composite . in this study , cohesive failure was seen in etch - and - rinse groups more than self - etch groups . within the limitations of this study , it can be concluded that dentin contamination with viscostat hemostatic agent had an adverse effect on the shear bond strength of two - step self - etch adhesive , adhese , and reduced it .
aim : this study investigated the effect of one hemostatic agent on the shear bond strength of self - etch and etch - and - rinse adhesive systems.materials and methods : sixty extracted third molars were selected . after preparing a flat surface of superficial dentin 
 , they were randomly divided into six groups . 
 adhesives were tetric n - bond , adhese , and adhese one f. before applying adhesives , surfaces were contaminated with viscostat for 60 s in three groups and rinsed . then composite were attached to surfaces and light cured . 
 after thermocycling , the bond strength was calculated and failure modes were determined by stereomicroscope . 
 the data were analyzed by t - test and one - way anova with p < 0.05 as the level of significance.results:viscostat had significantly decreased the shear bond strength of adhese ( p < 0.0001 ) to dentin . 
 modes of failures in all groups were mainly adhesive.conclusion:contamination had an adverse effect on the shear bond strength of adhese and reduced it .