Real‐time chemical analysis of root filling materials with heating: guidelines for safe temperature levels

Abstract

Atmeh AR, Hadis M, Camilleri J. Real-time chemical analysis of root filling materials with heating: guidelines for safe temperature levels. International Endodontic Journal, 53, -708, 2020. Aim To investigate the chemical changes affecting different types of gutta-percha and endodontic sealers during heating, and correlate changes with the heating capacity of different heat carriers. Methodology The heating capacity of three endodontic heat carriers was evaluated using thermocouples to produce heat profiles. The devices were activated at different temperature set-ups, in continuous or cut-out modes. Chemical changes of six brands of gutta-percha and four types of sealers were assessed in real time during heating using micro-Raman spectroscopy equipped with a heating stage. Raman spectra of each tested material were averaged and compared at different temperature levels. The sealers were further assessed by Fourier transform infrared (FT-IR) spectroscopy. Results None of the tested heat carriers achieved the temperature levels that were set by the devices and recommended by the manufacturer. The use of continuous heating mode resulted in higher rises in temperature than the 4 s cut-out mode that reached 110°C. The various brands of gutta-percha exhibited different chemical changes in response to heat. Some changes even occurred below temperature levels generated by the heating devices. All sealers revealed changes in their chemical composition upon heating. Changes in epoxy resin-and zinc oxide-eugenol-based sealers were detectable at 100°C, with structural alterations beyond that temperature and irreversible changes after cooling. Water loss was irreversible in BioRoot, but its chemical structure was stable as well as for the TotalFill. Conclusions The heating capacity of endodontic heat carriers needs to be standardized, so that the temperatures delivered by the tips are the same as that set on the dial. Practitioners should be aware of the actual temperatures generated by these devices, and the suitability of sealers to be used at the temperature levels achieved. 698

Physico-Chemical Investigation of Endodontic Sealers Exposed to Simulated Intracanal Heat Application: Hydraulic Calcium Silicate-Based Sealers

“…To address the outcome of clinical orientated thermal processing, a range of temperature was chosen [10]. In addition, the long-term effect of thermal processing on the setting reaction was addressed, as studies so far only assessed the effect of heat within the moment of thermal treatment [12] or after the primary setting reaction [11,13]. As prolonged hydration and structure maturation of calcium silicate-based materials have been reported [16], the effect of thermal treatment on the final constitution of the sealers has remained unknown so far.…”

“…While the physical properties of TFHF were not negatively affected by heat, BR and TFBC were reported for increased viscosity [11]. Chemical changes were found in TFBC during the thermal treatment, but reported to remiss after the cooling process while BR was reported as having persisting chemical changes [12]. Shortly after setting, no alterations were reported for TFHF, TFBC, and BioRoot RCS after initial thermal treatment [11].…”

“…Other calcium silicate-based sealers like Total Fill BC Sealer (TFBC; FKG Dentaire) or BioRoot RCS (BR; Septodont, St. Maur-des-Fossés, France) have recently been investigated regarding their behavior when exposed to heat application. Physical and chemical properties were investigated, during or shortly after the application of heat [11][12][13][14][15]. While the physical properties of TFHF were not negatively affected by heat, BR and TFBC were reported for increased viscosity [11].…”

Heating stability, physical and chemical analysis of calcium silicate‐based endodontic sealers

“…2016, Atmeh et al . 2020). In powder/liquid sealers, the hydration is initiated prior to their insertion into the root canal.…”

Effects of heating on the physical properties of premixed calcium silicate-based root canal sealers

“…Adaptation of gutta-percha to the root canal wall may be better with the warm vertical compaction technique than with the lateral condensation and single-cone techniques, as it allows for a homogeneous and dense root canal filling that adapts to the irregularities of root canals [4][5][6][7]. However, heat has been reported to alter the physical properties of some root canal sealers and the composition of the set products [8][9][10][11][12][13][14]. In particular, data for the epoxy resin root canal sealer AH Plus (DeTrey Dentsply, Konstanz, Germany) indicate shortened setting time and increased film thickness [9][10][11]14], as well as chemical changes such as loss of the amino group and changes in the structure of the resin [8,9,[11][12][13].…”