Amalgam restorations: postoperative sensitivity as a function of liner treatment and cavity depth

The purpose of this clinical study was to assess the sensitivity reported by patients following the insertion of class 1 or class 2 amalgam restorations in the treatment of primary carious lesions of different depths. Ninety subjects with previously untreated teeth requiring restorations due to caries lesions were selected: 32 teeth had lesions that were clinically and radiographically judged to be located in the outer one-third of dentin, 30 were located in the middle one-third of dentin, and 28 were located in the inner one-third of dentin. Four different lining regimens were employed: Group 1--no linear; Group 2--two coats of Copalite liner; Group 3--a dentin adhesive resin liner (Scotchbond Multi-Purpose); Group 4--a resin-modified glass ionomer (Fuji Bond LC). Patients were contacted on days 2 and 7 postoperatively and questioned regarding the presence or absence of sensitivity, the stimuli that created the sensitivity, if any, the duration of any sensitivity, and the intensity of any sensitivity using a rating from None to Severe. If sensitivity was experienced on day 7, patients were also contacted on days 14, 30, and 90 to assess the sensitivity at those intervals. The chi-square test of independence showed no significance at the 0.05 level between the different dentin treatments and cavity depths. By day 2, 19% of lesions located in the outer one-third, 27% of lesions located in the middle one-third, and 29% of lesions located in the inner one-third of dentin were sensitive. On day 30, four teeth were still sensitive, two located in the middle one-third and two located in the outer one-third of dentin. On day 90 all teeth were without sensitivity.