Table 4 Comparison of pre- and postexposure micronucleus cell count within group 2 (panoramic radiography)

From: Genotoxic effects of X-rays in buccal mucosal cells in children subjected to dental radiographs

Exposure Mean s.d. s.e. of mean Mean difference Z P-value
Pre-exposure to panoramic X-ray 4.20 0.77 0.17 −3.950 −3.947 <0.001a
Postexposure to panoramic X-ray 8.15 0.81 0.18    
  1. The mean s.d. and mean difference of pre- and post-micronucleus in group 2.
  2. The increase in mean number of cells with micronucleus from pre-exposure to postexposure was found to be statistically significant (P<0.001).
  3. aSignificant difference.