COMPARISON OF 3 METHODS OF CRITICAL-EVALUATION OF MICROLEAKAGE ALONG RESTORATIVE INTERFACES

This in vitro study compared microleakage along the dentin-restorative interface by use of a conventional single-surface and two stereoscopi cal protocols. The extent of microleakage in class V cylindric cavitie s that were restored with Scotchbond 2/P-50 was assessed after thermoc ycling and silver staining were performed. Specimens were randomized i nto three groups of 10 teeth for the three different protocols to be i nvestigated. The categories were group 1, a single longitudinal sectio n through the midline of the restoration, group 2, a multiple-surface protocol based on computer reconstruction of digitized images from mul tiple serial abrasions, and group 3, a clearing protocol based on imme rsion of demineralized specimens in methyl salicylate. The severity of microleakage for all groups was recorded on an ordinal scale and base d on linear leakage length. The median leakage score for groups 1 thro ugh 3 was 2, 4, and 4, respectively. When comparisons were performed w ith nonparametric statistical analysis, both the clearing and the mult iple-surface protocols recorded significantly more severe leakage than those detected from a conventional, single longitudinal, midline sect ioning technique, (x(2) = 8.595, p < 0.02). Furthermore microleakage p atterns generated from the two stereoscopical protocols revealed exten sive microleakage that advanced unilaterally or bilaterally through th e dentin-restorative interface along the embrasure regions into the ax ial wall of the restorations. No significant difference was noted betw een the two stereoscopical protocols (Q = 0.260, p > 0.05), which sugg ested that the clearing protocol, which is less labor-intensive than t he multiple-surface protocol, may be recommended for future comparativ e microleakage studies that involve the dentin-restorative interface.