SCANNING ELECTRON-MICROSCOPIC EVALUATION OF 2 COMPACTION TECHNIQUES USING A COMPOSITE RESIN AS A ROOT-CANAL FILLING MATERIAL

The canals of 20 human dental roots were instrumented using a step-bac k technique. The smear layer was removed, and the canals were obturate d with composite resin. Two different techniques of compaction were us ed: either vertical or lateral motions were used to condense composite resin inside the root canal that was then photopolymerized layer by l ayer using the argon laser (488 nm). The beam was delivered into the r oot canal by means of an optical fiber 320 mu m in diameter. Longitudi nal and cross-sections of the samples and resin replicas of the root c anals were examined using a light and scanning electron microscope. Sc anning electron microscopic examination revealed that laterally compac ted resin fillings showed fewer voids than those obtained by vertical compaction. In both experimental groups, adhesion of the resin to the dentin walls, pulled-out resin tags, microfailure, and resin fracture, leaving a layer of resin associated with the wall surface were observ ed.