Authors: Baumgartner JC, Mader CL.
Title: A scanning electron microscopic evaluation of four root canal irrigation regimens.
Journal: J Endod
Date: Apr 1987
Citation: 13(4):147-57
Category: Irrigants and Medicaments
Evidence-based Ranking: 5
Purpose/Objectives: To compare the debridement capabilities of a 0.9% saline solution with a 5.25% solution of NaOCl, a 15% solution of EDTA, and the combination of a 5.25% solution of NaOCl and 15% EDTA used alternately on both the instrumented and uninstrumented surfaces of the root canal walls.

Materials & Methods: Matched pairs of single canal bicuspids extracted for orthodontic purposes were used. 2 Control groups were set up, One non-instrumented, one instrumented. 3 test groups were used to compare the debridement capabilities of the solutions. In the test groups one canal was instrumented, while the other side was not, and each received the irrigant to be tested. The canals of each test specimen were scanned on both the instrumented and uninstrumented halves. Photomicrographs were used from 150x to 4,000x.

Results: High power magnification shows the fibrous nature of the unextirpated pulps, and the collagenous fibers of the pulps seen as masses or bundles of interwoven fibers. In specimens which had their pulps extirpated, the surfaces appeared smooth and clean at low power, but residual fibers and debris could be seen on the canal wall under higher power. The orifices of the tubules beneath the fibers could also be seen. The different ability of the irrigants is recorded and the conclusions relate their actions.

Author’s Conclusion: 1. All of the irrigation regimens used removed superficial debris. 2. During instrumentation and irrigation with saline or NaOCl alone, a typical amorphous smear layer was formed. 3. EDTA used alone demineralized the smear layer formed during instrumentation. 4. Without instrumentation, if saline or EDTA were used, neither pulpal remnants nor predentin was removed from the un-treated halves of the root canal. 5. When NaOCl was used alone, all the pulpal remnants and predentin were removed from the unistrumented halves. 6. When a combination of NaOCl and EDTA were used, the pulpal remnants and the smear layer were completely removed from both the un- and instrumented halves, leaving a smoothly planed surface with patent tubular orifices. 7. When NaOCl and EDTA were used in combination, some surface erosion occurred in the uninstrumented halves.

Reviewer’s Comments: This article justifies the use of NaOCl for the removal of the organic debris within the root canal system, and the use of EDTA for removal of the inorganic components within the root canal system.