RESULTS No statistical significant difference in bond strength between both categories was observed in caries-affected dentin at immediate evaluation and in sound dentin after ageing .
Etch- and -rinse adhesives , however , performed better in sound enamel and dentin substrates considering immediate bond strength .
None study assessed the long-term adhesive effectiveness to sound or demineralized enamel .
Although the articles included in this meta- analysis showed high heterogeneity and high risk of bias , the in vitro literature suggests superior performance of etch- and -rinse adhesives in primary teeth in comparison with self-etch systems
AIM To systematic ally review the literature for in vitro studies that evaluated the immediate or after ageing bond strength of  etch- and -rinse and self-etch adhesive systems to enamel and dentin of primary teeth .
Primary dentin etching time, bond strength and ultra-structure characterization of dentin surfaces.
OBJECTIVES To evaluate the effect of shortening the etching time on roughness , microhardness and bond strength of three adhesive systems to primary tooth dentin . METHODS Flat dentin surfaces from primary molars were r and omly assigned to six experimental groups . Three different adhesive systems were used : an etch- and -rinse adhesive ( Single Bond ) , a two-step self-etching ( Clearfil SE Bond ) , and a one-step self-etching ( One-Up Bond F ) adhesive . In half of the specimens , the recommended etching time was used , in the other half the etching time was 50 % reduced . After applying the adhesive , resin composite build-ups were constructed and stored in a humid environment for 24h at 37 degrees C. Specimens were sectioned into 1mm(2 ) beams and tested for microtensile bond strength ( MTBS ) . Debonded surfaces were analyzed by scanning electron microscopy ( SEM ) . Additional surfaces were conditioned for microhardness measurements ( KHN ) and for atomic force microscopy ( AFM ) analysis . Intertubular and total surface roughness ( Ra ) were recorded . Results were analyzed with ANOVA and Student-Newman-Keuls tests ( P<0.05 ) . RESULTS Single Bond and Clearfil SE Bond showed higher MTBS than One-Up Bond F. Bond strength and intertubular roughness increased when Single Bond and One-Up Bond F were used with a reduced etching time . For Clearfil SE Bond no differences in MTBS were detected when reducing the etching time . The application of phosphoric acid , Clearfil SE Bond primer and One-Up Bond F decreases dentin microhardness . CONCLUSIONS Shortening One-Up Bond F application time and reducing the etching time of phosphoric acid to one-half of the manufacturer 's recommended etching time when using Single Bond are recommended when bonding to primary dentin
RESULTS No statistical significant difference in bond strength between both categories was observed in caries-affected dentin at immediate evaluation and in sound dentin after ageing .
Etch- and -rinse adhesives , however , performed better in sound enamel and dentin substrates considering immediate bond strength .
None study assessed the long-term adhesive effectiveness to sound or demineralized enamel .
Although the articles included in this meta- analysis showed high heterogeneity and high risk of bias , the in vitro literature suggests superior performance of etch- and -rinse adhesives in primary teeth in comparison with self-etch systems
AIM To systematic ally review the literature for in vitro studies that evaluated the immediate or after ageing bond strength of  etch- and -rinse and self-etch adhesive systems to enamel and dentin of primary teeth .