SIGNIFICANCE This study did not identify clear advantages of using the first generation of ormocer-based fillings rather than conventional composites .
OBJECTIVES In-vitro experiments on  ormocers ( ORganically MOdified CERamics )  have provided controversial results .
Consequently , the objectives of this meta- analysis were to ( 1 ) compare clinical performances of first generation ormocers versus conventional composite restorations  , ( 2 ) explore the influence of various clinical factors and the impact of the quality of studies on published results .
Randomized 3-year clinical evaluation of Class I and II posterior resin restorations placed with a bulk-fill resin composite and a one-step self-etching adhesive.
PURPOSE To evaluate the 3-year clinical durability of the flowable bulk-fill resin composite SDR in Class I and Class II restorations . MATERIAL S AND METHODS Thirty-eight pairs of Class I and 62 pairs of Class II restorations were placed in 44 male and 42 female patients ( mean age 52.4 years ) . Each patient received at least two extended Class I or Class II restorations that were as similar as possible . In all cavities , a one-step self-etching adhesive ( XenoV+ ) was applied . One of the cavities of each pair was r and omly assigned to receive the flowable bulk-fill resin composite SDR in increments up to 4 mm as needed to fill the cavity 2 mm short of the occlusal cavosurface . The occlusal part was completed with an ormocer-based nanohybrid resin composite ( Ceram X mono+ ) . In the other cavity , only the resin composite CeramX mono+ was placed in 2 mm increments . The restorations were evaluated using slightly modified USPHS criteria at baseline and then annually for 3 years . Caries risk and bruxing habits of the participants were estimated . RESULTS No post-operative sensitivity was reported . At the 3-year follow-up , 196 restorations - 74 Class I and 122 Class II - were evaluated . Seven restorations failed ( 3.6 % ) , 4 SDR-CeramX mono+ and 3 CeramX mono+ only restorations , all of which were Class II . The main reason for failure was tooth fracture , followed by resin composite fracture . The annual failure rate ( AFR ) for all restorations ( Class I and II ) was 1.2 % for the bulkfilled restorations and 1.0 % for the resin composite-only restorations ( p > 0.05 ) . For the Class II restorations , the AFR was 2.2 % and 1.6 % , respectively . CONCLUSION The 4-mm bulk-fill technique showed good clinical effectiveness during the 3-year follow-up
SIGNIFICANCE This study did not identify clear advantages of using the first generation of ormocer-based fillings rather than conventional composites .
OBJECTIVES In-vitro experiments on  ormocers ( ORganically MOdified CERamics )  have provided controversial results .
Consequently , the objectives of this meta- analysis were to ( 1 ) compare clinical performances of first generation ormocers versus conventional composite restorations  , ( 2 ) explore the influence of various clinical factors and the impact of the quality of studies on published results .