Einfluss des Feuchtigkeitsgehalts des Wurzelkanaldentins auf die Entstehung und den Nachweis von Mikrorissen - Eine Mikro-Computertomografie-Studie

Aim: This study aimed to evaluate the effect of moisture content of root canal dentin on detection of microcracks using micro-computed tomography. Methods: Ten roots with and without craze lines or cracks (each n = 5) were selected and scanned six times with different moisture conditions of root dentin using a micro-CT scanner at high resolution of 10.5 µm. Scanning conditions were as follows: 1. after 30 d wet storage, 2. after 2 h dry time, 3. after 48 h wet storage, 4. after 24 h dry time, 5. after 48 h wet storage, 6. after 2 h dry time. From each scan, cross-sectional images were obtained at intervals of 1 mm (total n = 708) and evaluated for the presence of dentinal microcracks twice by 5 calibrated blinded observers. Statistical analysis was performed by nonparametric analysis of variance (P < .05). Results: No significant differences between all wet groups as well as between both groups with 2 h dry time were detected (P > .05). Almost no cracks were observed after wet storage with a significant increase of cracks after 2 h dry time (P < .05). Significantly more microcracks were identified after 24 h than after 2 h dry time (P < .05). Conclusions: Moisture content of dentin influences detection of microcracks using micro-CT. Scanning should be performed on dried specimens to allow reliable identification of dentinal defects. Formation of new cracks during dry periods up to 24 h was disproved.