Role of the acid-etch technique in remineralization of caries-like lesions of enamel: a polarized light and scanning electron microscopic study.

The aim of this in vitro study was to determine the effect of acid-etching on remineralization of caries-like lesions with calcifying fluids (CF). Caries-like lesions were created in two windows of sound enamel on both buccal and lingual surfaces of human molars. A central longitudinal section was taken from each tooth to serve as control lesions (CL). Each tooth was then sectioned into quarters and each quarter assigned to one of four groups: 1) 1mM Ca CF Remineralized (RC1); 2) 1mM Ca CF Remineralized Etch (RE1); 3) 3mM Ca CF Remineralized (RC3); 4) 3mM Ca CF Remineralized Etch (RE3). Lesions in the etch groups were exposed to 30 percent H3PO4 for 30s prior to CF. Etch and non-etch groups were treated with 1mM or 3mM Ca CFs (prepared from HAP [Ca/P ratio = 1.63], pH 7.0, 0.05mM F-) for ten 60-second periods, interspersed with deionized water rinses. Mean lesion depths were determined using a digitized tablet. Following 1mM Ca CF, mean lesion depths were: 179 microns for CL, 157 microns for RC1 and 118 microns for RE1. Following 3mM Ca CF, mean lesion depths were: 188 microns for CL, 171 microns for RC3 and 143 microns for RE3. SEM topographic features of the remineralized etched lesions consisted of adherent surface coatings with finely globular patterns in the 1mM Ca CF group and densely adherent surface coatings which masked the effects of etching in the 3mM Ca CF group.(ABSTRACT TRUNCATED AT 250 WORDS)