According to this review , the 3-step adhesive systems were the best performing and still are the gold st and ard for the cementing of indirect restorations .
In addition , it can be concluded that self-etched adhesive systems reduce the time spent in clinical practice , however at the interface level they behave as permeable membranes more susceptible to degradation
New technologies are changing the therapeutical options to do indirect restorations and new adhesive systems are continuously introduced to be used by clinicians .
Different interactions between restorations , adhesive systems components , enamel and dentin require having criteria based on the selection of the adhesive system , ensuring the longevity of the restorations and the preservation of the biological remnant .
The adhesion force to the dental tissue is one of the indicatives of the behavior of the adhesive systems and influences the behavior of the treatments with direct and indirect restorations .
The objective of this search was to find the adhesive systems with the best results in terms of the adhesion strength of indirect restorations  on the dental tissues .
Four-year clinical evaluation of a self-adhesive luting agent for ceramic inlays
Objectives The aim of this r and omized controlled clinical trial was to evaluate the 4-year clinical performance of a self-adhesive resin cement , RelyX Unicem ( 3 M ESPE ) , used for cementation of ceramic inlays . In addition , the influence of selectively acid-etching enamel prior to luting on the clinical performance of the restorations was assessed . Methods Sixty-two IPS Empress 2 inlays/onlays were placed in 31 patients by two experienced clinicians . The restorations were luted with RelyX Unicem with ( = experimental group : E ) or without ( = control group : NE ) prior enamel etching with phosphoric acid . At baseline , 6 months , and 1 , 2 , and 4 years after placement , the restorations were assessed by two calibrated investigators using modified USPHS criteria . Ten selected sample s of each group were investigated under SEM regarding morphological changes at the cement – inlay interface . Results The recall rate at 4 years was 97 % . Two restorations ( 1 E , 1 NE ) were lost , and one ( E ) had to be replaced due to inlay and tooth fracture result ing in a survival rate of 95 % . No significant differences between the experimental and control group were noticed regarding all criteria ( McNemar , p < 0.05 ) . An obvious deterioration in marginal integrity was observed after 4 years as only 5 % ( E = 7 % ; NE = 3 % ) of the restorations exhibited an excellent marginal adaptation . In 90 % of the restorations small , still clinical ly acceptable marginal deficiencies were observed . SEM of the luting gap showed an increased wear of the RelyX Unicem cement over the 4-year period . Conclusions The self-adhesive luting cement RelyX Unicem can be recommended for bonding of ceramic inlays/onlays . Additional selective enamel etching does not improve the clinical performance of the restorations within the 4-year period . Clinical relevance The self-adhesive resin composite RelyX Unicem showed acceptable clinical performance after 4 years of clinical service
According to this review , the 3-step adhesive systems were the best performing and still are the gold st and ard for the cementing of indirect restorations .
In addition , it can be concluded that self-etched adhesive systems reduce the time spent in clinical practice , however at the interface level they behave as permeable membranes more susceptible to degradation
New technologies are changing the therapeutical options to do indirect restorations and new adhesive systems are continuously introduced to be used by clinicians .
Different interactions between restorations , adhesive systems components , enamel and dentin require having criteria based on the selection of the adhesive system , ensuring the longevity of the restorations and the preservation of the biological remnant .
The adhesion force to the dental tissue is one of the indicatives of the behavior of the adhesive systems and influences the behavior of the treatments with direct and indirect restorations .
The objective of this search was to find the adhesive systems with the best results in terms of the adhesion strength of indirect restorations  on the dental tissues .