Abstract: Abstract: Objective Taking traditional layering dental resin as a contrast to compare in vitro microleakage and operation time of the three types of latter teeth filled with chunks of resin. Methods 40 unified in vitro molars were selected, in facies occlusalis of tooth preparation 4mm×4mm×4mm hole of class I, then were randomly divided into A, B, C, D four groups The four groups were filled with SonicFill resin, SureFil SDR flowable resin, Tetric N-Ceram bulk Fill resin, Filtek Z350 resin filling, and each sample filling time of completion was recorded. After the thermal cycle test, the filling samples were put into India ink soak for 24h. After drying the sample was cut along the mesial and distal . Sample dye penetration depth was stereoscopically viewed under a microscope , and then counted and measured and analyzed statistically. Results The operation time difference of four groups : there were no significant differences between group A and B P=0.791（P>0.05）;the rest of the pairwise comparison were significant differences P=0.000（P<0.05）;C group consumed the least ,while traditional layering D group consumed the most. Micro-leakage occurred in four groups, but four groups had no significant differences P=0.727（P>0.05）.Conclusion The three kinds of latter teeth filled with chunks of resin can achieve the same edge of the closed nature compared with conventional layering and its operating time is shorter than the latter, easy to operate.

Key words: Key words: Filling chunks, Resin, Operating time, Microleakage