Objective: The purpose of this clinical study was to assess the sensitivity experienced and reported by patients following treatment of primary carious lesions with Class I or Class II amalgam restorations. Method and materials: Only previously untreated teeth were selected. The cavity preparations were treated according to one of four regimens: group 1 = no liner; group 2 = two coats of a copal varnish; group 3 = a dentin adhesive resin li ner; group 4 = a resin-modified glass-ionomer liner. Patients were contacted on days 2 and 7 postoperatively and questioned regarding the presence or absen ce of sensitivity. If sensitivity was experienced, they were asked which stimuli created the sensitivity, the length of time it lasted, and its intensity on a subjective scale. If sensitivity was experienced on day 7, patients were also contacted on days 14, 30, and 90 to assess the degree of sensitivity. Nineteen teeth were included in each of the four groups. Results: By days 2 and 7, no significant difference existed among groups; by day 14, 22% of restorations in group 2 and 17% of those in group 3 were sensitive, while teeth in groups 1 and 4 exhibited no sensitivity reactions. Conclusion: Use of a resin-modified glass-ionomer liner or no dentin treatment resulted in short-term sensitivity in fewer than one third of the teeth. Almost one third of the teeth restored with a dentin adhesive resin liner or copal varnish exhibited initial sensitivity, which lasted up to 30 days in a few teeth.