Resin–Dentin Bonding Interface After Photochemical Surface Treatment

Abstract

Objective: The aim of this study is to elucidate the structure of the resin-dentin interface formed by photochemical dentin treatment using an argon fluoride (ArF) excimer laser. Background data: The ArF excimer laser processes material by photochemical reaction without generating heat, while also providing surface conditioning that enhances material adhesion. In the case of bonding between resin and dentin, we demonstrated in a previous study that laser etching using an ArF excimer laser produced bonding strength comparable to that of the traditional bonding process; however, conditions of the bonding interface have not been fully investigated. Methods: A dentin surface was irradiated in air with an ArF excimer laser followed by bonding treatment. Cross sections were observed under light microscope, transmission electron microscope (TEM), and scanning electron microscope, then analyzed using an energy dispersive X-ray spectroscope (EDS): EDS line profiles of the elements C, O, Si, Cl, P, and Ca at the resin-dentin interface were obtained. Results: The density of C in resin decreased as it approached the interface, reaching its lowest level within the dentin at a depth of 2 lm from the resin-dentin interface on EDS. There was no hybrid layer observed at the interface on TEM. Therefore, it was suggested that the resin monomer infiltrated into the microspaces produced on the dentin surface by laser abrasion. Conclusions: The monomer infiltration without hybrid layer is thought to be the adhesion mechanism after laser etching. Therefore, the photochemical processes at the bonding interface achieved using the ArF excimer laser has great potential to be developed into a new bonding system in dentistry.

How 10-MDP functional phosphate monomer and 2% digluconate chlorhexidine solution interact on sound, artificial carious or eroded dentin substrates

“…The variations observed between the components may be due to different positions of the analysis inside the interface, with prevalence of dentin or resin, which varied trouhgh the observation of Ca levels, for instance, although the size of the evaluation area is approximately the same in all assessments (60µm 2 ). These findings are in accordance with the literature that shows these same elements at the resin-dentin bonding interface, varying their concentrations if they are closer to the dentin or resin, as the carbon decrease when approaching the hybrid layer (TONAMI et al, 2015).…”

Electron microscopic observation of photoreceptor cells in directly inserted anesthetized Drosophila into a high‐pressure freezing unit

“…STEM/TEM and mapping images of chloride (Cl: Figure 4b) and phosphorus (P: Figure 4c) were compared after obtaining spectra of Cl ( Figure 4d) and P (Figure 4f ), the two elements were found to be rarely distributed in the electron lucent areas (Figure 4d). As Cl is known to be contained in epoxy resin (Tonami, Sano, Ichinose, & Araki, 2015), these findings indicate that epoxy resin hardly infiltrated into these pigment-like granules for unknown reasons.…”