Influence of temperature protocols on smear layer removal and dentin erosion by triton all-in-one irrigation solution

Abstract Effective endodontic irrigation requires smear layer removal while preserving dentin integrity. Although multifunctional irrigants combine disinfection and chelation in a single solution, the effects of thermal activation on their behavior and dentin interaction remain unclear. The aim of this in vitro study was to evaluate the effects of temperature protocols on smear layer removal, dentin erosion, and selected physicochemical properties of Triton All-in-One irrigation solution. Ninety extracted single-rooted mandibular premolars were prepared with a Reciproc R25 file and irrigated exclusively with Triton. Using an in vitro experimental model, apical and external root surface temperatures were monitored with thermocouples. Specimens were assigned to room-temperature irrigation (22 °C), preheated irrigation (60 °C), or intracanal heating for 5, 10, or 15 s. Smear layer removal and dentin erosion were evaluated by scanning electron microscopy using modified Hülsmann criteria. As complementary analyses, the physicochemical properties of the Triton irrigation solution, including pH, available chlorine, and surface tension, were assessed, together with calcium ion release following dentin interaction. Intracanal temperature change (ΔT = Tmax − T0) differed significantly among the experimental groups ( p < 0.001), with progressively greater increases observed as the duration of intracanal heating increased. External root-surface temperature increases remained below 2 °C in all specimens under the present experimental conditions. Temperature elevation enhanced smear layer removal by Triton ( p < 0.001), reduced surface tension, and increased calcium ion release. Preheated irrigation improved smear layer removal compared with room-temperature irrigation while producing lower erosion scores and reduced calcium ion release than prolonged intracanal heating. Thermal activation enhanced the cleaning efficacy of Triton; however, dentin alteration depended on the thermal protocol. Preheated irrigation improved smear layer removal while producing less dentin erosion and calcium ion release than prolonged intracanal heating. The clinical significance of these findings requires further functional validation.