The meta- analysis of the data in the included studies demonstrated that only one variable ( marginal adaptation after 12 months ) showed statistically significant outcomes , in which methacrylates-based composites presented significantly better results than resin composites containing modified monomers .
The good level of the scientific evidence as well as the overall low risk of bias of the included studies indicate that composites with silorane , ormocer or bulk-fill type modified monomers have a clinical performance similar to conventional resin composites
Polymerization shrinkage of resin composite can compromise the longevity of restorations .
To minimize this problem , the monomeric composition of composites have been modified .
The objective of this study was to conduct a meta- analysis to assess the clinical behavior of restorations performed with low polymerization shrinkage resin composite  in comparison with traditional methacrylates-based resin composite .
One-year evaluation of two hybrid composites placed in a randomized-controlled clinical trial.
OBJECTIVE The aim of this prospect i ve r and omized-controlled clinical trial is to assess the long-term performance of two direct composite resins in posterior teeth . This study provides a survey of the one-year results . MATERIAL S AND METHODS A total of 1805 restorations were placed by students in stress-bearing Class I/II cavities ( including cuspal-coverage ) in molars and premolars in 456 patients . Clinical evaluation was performed at baseline and after one year using modified USPHS criteria . The restorations in each patient were performed either with Ceram X/Prime&Bond NT or Tetric Ceram/Optibond Solo Plus . RESULTS After one year 528 fillings with Ceram X and 580 with Tetric Ceram were available for evaluation of substance loss , contact point , color match , marginal staining , marginal adaptation , secondary caries and radiographic examination ( if necessary ) . This represents a recall rate of 61.18 % ( 279 patients ) . The failure rate per material was 5.3 % in the Ceram X group and 6.1 % in the Tetric Ceram group . Most of the failures were associated with marginal adaptation/integrity of the filling . A significant influence on the occurrence of a failure was observed for the number of treated teeth per patient , the age of the patient , the mesio-distal extension of the restoration and the tooth position . Gender , material , a previous root canal treatment , the bucco-lingual extension of the filling or cuspal-coverage did not significantly influence the failure rate . Patients attending the first recall were significantly older and had more fillings than patients not attending . CONCLUSIONS In a group of Class I/II restorations ( including cuspal-coverage ) , there was no significant difference in failure rates between ormocer-based and bis-GMA-based restorative systems after one year . A previous root canal treatment had no negative influence on the failure rate . A longer observation period is indicated to get clear evidence of the long-term performance of these composite resin systems
The meta- analysis of the data in the included studies demonstrated that only one variable ( marginal adaptation after 12 months ) showed statistically significant outcomes , in which methacrylates-based composites presented significantly better results than resin composites containing modified monomers .
The good level of the scientific evidence as well as the overall low risk of bias of the included studies indicate that composites with silorane , ormocer or bulk-fill type modified monomers have a clinical performance similar to conventional resin composites
Polymerization shrinkage of resin composite can compromise the longevity of restorations .
To minimize this problem , the monomeric composition of composites have been modified .
The objective of this study was to conduct a meta- analysis to assess the clinical behavior of restorations performed with low polymerization shrinkage resin composite  in comparison with traditional methacrylates-based resin composite .