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

By Tanzilli JP, Raphael D, Moodnik RM

Date: 08/1990
Journal: Oral Surg Oral Med Oral Patho


Purpose: to examine the adaptability of retrograde amalgam, heat-sealed guttapercha, and cold-burnished gutta-percha to the dentin- retrograde material interface of the root canal

N= 40 extracted central incisors


•Cleaning and shaping up to size #60 file, the canals were filled with laterally condensed gutta percha

•The apicoectomy was performed by beveling the apical 2 mm of the roots •Group I: retrograde amalgam: a Class I preparation with a bur to 2 mm depth; amalgam was placed

•Group II: heat-sealed GP: a warm plastic instrument used over the GP to seal the apex

•Group III: cold burnished GP: a ball burnisher was used to compress the GP back into the canal space

•Group IV: the control group in which the apex was left untouched after beveling

•The specimens were examined by SEM

Most highlighted Results:

•The retrograde amalgam produced defects averaging 22 μm, unsupported ledges of amalgam

•Heat sealed gutta-percha produced defects averaging 6.5 μm,  and shows blisters and pull-away of GP

•The cold-burnishing gave the smoothest appearance and consistently good adaptation with an average defect of 1.8 μm

•Control group showed an average defect of 28 μm with blistering

Clinical significance: the amalgam well create a defect between the dentine surface and the amalgam, and this is one of the