Purpose: to evaluate & compare the time-dependent chemical and ultramorphologic effects of (EDTA) and (NaOCl) in young and old dentin
N= 64 extracted teeth
•Teeth were collected from young (<30 years) and old (>60 years) patients. •In 48 teeth, the dentin was reduced to a powder state and treated with EDTA or EDTA + NaOCl for 1 and 10 minutes, respectively.
•X-ray diffraction analysis was used to determine the changes in the composition of dentin through dissolution of hydroxyapatite (HAp).
•In the remaining teeth (n = 16), the root canals were prepared, bisected, and subjected to the same time-dependent treatment regimens.
•The changes in the number and area of dentinal tubules were calculated by image analysis.
Most highlighted Results:
In young root dentin – 10-minute treatment with EDTA + NaOCl does not significantly alter the chemical & ultramorphologic structure and thus appears to be unnecessary.
In old dentin – extended treatment time with EDTA + NaOCl should be avoided owing to excessive demineralization and erosion.
In both types of dentin, EDTA was not effective in complete removal of the smear layer