The William's blister test for adhesion was used to determine the strength of epithelial and fibroblast cell attachments to cementum, dentin and enamel. Differences of air pressure required (cm H2O) to debond the samples from a cell monolayer were measured and recorded on a strip chart recorder (Fletcher et al. 1977). Gingival and skin‐muscle cells detached at similar pressures from cementum, dentin and enamel. Higher pressures (of debond) were required with cells grown on a polystyrene surface.