Table 3 Comparison of pre- and postexposure micronucleus cell count in group 1 (bitewing 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 bitewing X-ray 2.80 0.70 0.16 −3.250 −3.940 <0.001a
Postexposure to bitewing X-ray 6.05 1.10 0.25    
  1. The mean, s.d. and mean difference of pre- and post-micronucleus in group 1.
  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.