The Impact of Thermocycling Process on the Dislodgement Force of Different Endodontic Cements

Abstract

To evaluate the effects of thermocycling (500 cycles, 5°C/55°C) on the push-out bond strength of calcium silicate based cements including WMTA, Nano-WMTA, and Bioaggregate to root dentin. Forty-eight dentin slices were prepared and divided into 3 groups (n = 16) and filled with Angelus WMTA, Nano-WMTA, or Bioaggregate. After incubation, half of the samples were thermocycled while the other half remained untreated. Push-out bond strength was calculated, and the modes of the bond failures were determined by SEM. The highest bond strength was seen in nonthermocycled Nano-WMTA samples and the lowest in thermocycled Bioaggregate samples. The significant differences between nonthermocycled and thermocycled samples were only noticed in WMTA and Nano-WMTA groups (P < 0.001). The mode of failure for thermocycled samples of all three cements was mostly cohesive. Thermocycling process can drastically affect the push-out bond strength of calcium silicate based cements. The intrastructural damages occurred due to the thermal stresses, causing cohesive failures in set materials. Sealing property of endodontic cements which have experienced the thermal stresses can be jeopardized due to occlusal forces happening in furcation cites.

Effect of Thermocycling on Nickel Release from Orthodontic Arch Wires: an In Vitro Study

“…Corrosion, the graded degradation of materials by electrochemical attack, is of concern particularly when orthodontic appliances are placed in the hostile electrolytic environment provided by the human mouth [36]. Investigators have shown that thermocycling regimen comprising a minimum of 500 cycles in water between 5 and 55°C is an appropriate artificial aging test [26,35]. The results of the current study revealed that thermocycling has a significant effect on the release of Ni from orthodontic appliances.…”

“…Atomic adsorption spectrometer analysis is an effective, dependable, and feasible method to evaluate the amount of ion released from orthodontic wires in aqueous solutions [27,33]. It has been reported that temperature changes influence the physical and chemical properties of dental materials and most orthodontic appliances [22,24,26]. Thus, the current study aimed to evaluate the effect of pH changes and thermocycling, as the two main factors that change many times during the day after each meal and drink, on the amount of Ni released from orthodontic appliances.…”

“…Artificial saliva was prepared by following the formula used by Saghiri et al [26]. The pH was adjusted at 4.5 by adding increments of ascorbic acid.…”

“…All the Pyrex tubes were immersed in distilled water for 48 h at 37°C. The tubes in groups 1 and 3 did not receive any treatment, while groups 2 and 4 were subjected to thermocycling using a device the same as that used by Saghiri et al [26]. Thermocycling process was performed in water with the temperature ranging between 5 and 55°C for 500 cycles.…”

Radiopacifier Particle Size Impacts the Physical Properties of Tricalcium Silicate–based Cements

“…Nano WMTA showed significant improvements in the physiochemical properties of CSCs such as setting time, microhardness (17), push-out bond strength (18, 19), compressive strength (20), osseous reaction (21), and resistance in acidic environments (22). …”