Temperatureinfluss auf den Haftverbund des calciumsilikatbasierten Wurzelkanalsealers CeraSeal zum Kanalwanddentin

2.1 Background and Objectives There are different methods to perform a root canal treatment in clinical routine. In particular the hot filling methods, such as warm vertical compaction technique, or other endodontic treatments using heat carrier are known for their good clinical results. The heated filling material is able to obturate lateral canals and can be condensed easily. The influence of temperature on adhesion between the root canal sealer and dentine is still to be further investigated. Bond strength depends on the root canal filling paste used, hereinafter referred to as sealer. Up to now little data is available about the new calcium-silicate-based Sealer CeraSeal by Meta Biomed. We aimed to investigate the influence of temperature on the bond strength of CeraSeal to the root canal dentine. Furthermore, the fracture modes of the spreaders were analyzed to determine and evaluate any differences in the type of fracture that has occurred. 2.2 Materials and Methods 60 human extracted teeth were examined radiologically, decoronated, measured and the 8 mm straight root canals were preparated manually and by machine to ISO 60. During the preparation the root canal was irrigated with different rinsing solutions. After randomizing the teeth into 6 groups (n=10), the temperatures for the experimental groups were determined and the radiated spreaders brought to the following temperatures: group 1: 37°C, group 2: 65°C, group 3: 85°C, group 4: 105°C, group 5: 125°C, group 6: 145°C. The root canals were pretreated prior to an obturation with an alternating irrigation of 3% sodium hypochlorite and EDTA. After that, the bioceramic sealer CeraSeal was applied into the root canal and the heated spreaders were inserted into the teeth. The specimens were stored for 4 weeks at 37°C. After storage the spreaders were debonded in a pull-out test to analyse the bond strength depending on the simulated obturation temperature. This was followed by the analysis of the fracture mode of the extracted spreaders. To precisely determine the individual length of the respective sample, an X-ray analysis was carried out in advance. 2.3 Results There was no significant difference between the six experimental groups in either the ANOVA or the corresponding post-hoc tests (p = 0.721). The highest median bond strength values of the bioceramic sealer CeraSeal were achieved at 125°C (3.58 MPa). High adhesion values could also be measured at a temperature of 65°C (3.18 MPa), whereas the lowest adhesion values occurred at 85°C (2.38 MPa). The measured bond strength showed a low variance. When evaluating the fracture modes the cohesive fracture was found to be the most frequent one with 36.67%. 2.4 Conclusions There were no significant differences in the bond strength measured between the groups. Therefore the results of the present study do not indicate that the bond strength of the bioceramic sealer CeraSeal to root canal dentine could be affected by different obturation temperatures as performed in the present study. It can be assumed that the investigated sealer CeraSeal may be suitable for warm obturation techniques using the temperature rage performed in the present study.