A Randomized Controlled Trial in Class II: 7-year Results

Objective: The aim of the study was to test one ormocer with or without a flow in class II with margins in dentin, using as control a nano-hybrid composite with or without flow, for testing the null hypothesis that there was no difference between different bonding and restorative materials and using or not a liner. Method: A computer-generated random numbers table and the concealment in sealed envelopes were used and 120 patients,50 males and 70 females, aged between 21 and 61, respecting the inclusion-exclusion criteria, were selected with a total of 480 teeth. The materials were Futura bonding + Grandio  (FG), Futura bonding + Flow+Grandio (FFG) (Voco),  Prompt-L-Pop+ Supreme(PS), Prompt-L-Pop+Flow+ Supreme(PFS) (3M-Espe). Any patient received 4 restorations, one for any group. The procedures were done according with manufacturer's instructions with the same clinical protocol by two expert operators. The restorations were evaluated by one independent examiners with an intra- agreement >80%, with a loop (4.5x) according with USPHS modified criteria at baseline, 6,12,24,36,60, 84 months. A statistical analysis with Mann-Whitney non parametric test was performed (p<0.05). Result: After 84 months 70 patients and 180 restorations were assessed: we had 21 failures in premolars and 43 in molars, ratio 1:2. In 7 years FG showed 13 failures, FFG 10, PS 21, PFS 20. There was not a significant difference (p>.05) between FG and FFG, and between PS and PFS; there was a significant difference (p<.05) between Voco and 3M-Espe groups. The failures were concentrated between 5 and 7 years. Conclusion: Within the limits of this RCT, the null hypothesis was partially accepted, because the using a liner does not change the result, but was rejected concerning the different behaviour of bonding and restorative materials.