A comparison of the marginal adaptation of retrograde techniques: a scanning electron microscopic study

An investigation of the most popular retrograde technique for their marginal adaptation to dentin was attempted. Forty extracted maxillary central incisors were instrumented and obturated, and various apical procedures were performed. The scanning electron microscope was used to record the results. Retrograde amalgam, heat-sealed gutta-percha, and the apicoectomy control showed average marginal defects from 22 micron to 104 micron, while cold-burnished gutta-percha exhibited an average defect of only 1.8 micron. The marginal defect produced by cold-burnished gutta-percha is less than one tenth as large as the best of the other techniques.