Effect of cavity disinfection on postoperative sensitivity associated with amalgam restorations

This clinical study assessed the postoperative cold sensitivity reported by patients following the Class I and Class II amalgam restoration of primary carious lesions after different cavity treatments. One hundred and twenty patients, each with a previously untreated tooth requiring an amalgam restoration due to the presence of a carious lesion, were included. Sixty teeth had lesions that were radiographically judged to be located in the middle third of dentin, and another 60 were located in the inner third of dentin. Six different cavity treatment regimens were used: Group 1--no treatment; Group 2--calcium hydroxide liner (Life); Group 3--cavity varnish (Copalite); Group 4--resin modified glass ionomer liner (Vitrebond); Group 5--dentin adhesive resin liner (Single Bond); Group 6--chlorhexidine disinfectant (Consepsis). Patients were telephoned on days 2 and 7 postoperatively and asked whether they experienced sensitivity to cold, and if so, its duration and intensity. If sensitivity remained up to day 7, patients were also contacted on days 30 and 90. The Kruskal-Wallis test showed postoperative sensitivity to be significantly different among cavity treatments at days 2, 7 and 30 (p = 0.026, 0.044, 0.015, respectively). Lesion depth also affected postoperative sensitivity at day 2, with 27% of teeth with middle-third lesions producing pain, and 58% of those with lesions extending to the inner third producing pain (p = 0.000). This difference showed up at 7 and 30 days (p = 0.001, 0.015, respectively). Of the 51 teeth with sensitivity at day 2, 17 had mild pain, 26 were moderately painful and 8 had severe pain; each category reduced in degree of sensitivity and number with time. It would seem that medium-term (beyond 30 days) postoperative sensitivity is affected neither by the method of cavity treatment nor the depth of lesion, although, in the shorter-term, these factors do influence the postoperative sensitivity reported.