C

Acid etching/priming improves bond strength but does not change the intrinsic volumetric contraction of the resin; therefore it cannot “decrease polymerization shrinkage.”  Shrinkage stress actually rises when the ratio of bonded to un-bonded surfaces (C-factor) is high and this contraction can open marginal gaps that allow microleakage, but the amount of shrinkage is unaffected by etching/priming [Suh & Wang, 2001, PMID 11507797; Gallo et al., 2019, PMID 31554599; Segura et al., 1992, PMID 1287715].