Development of a radiopaque dental glass for endodontic laser applications

The aim of this study was to develop a laser-sinterable and radiopaque glass powder as a potential sealer in endodontic therapy. The hypothesis was that it is possible to dope a SiO2-Na2O-CaO-P2O5–based glass with barium (Ba) and tantalum (Ta) in such a way that the prepared glass powder can be sintered using a dental Er:YAG laser, with different parameters at different intensities. A reference glass (G1), a barium-doped glass (G2), and a tantalum-doped glass (G3) were investigated. Their chemistry, particle size distribution, structure, radiopacity, and sintering behavior were investigated using X-ray fluorescence (XRF), laser granulometry, X-ray diffractometry (XRD), X-ray imaging, and laser scanning microscopy (LSM). Sintering behavior was statistically analyzed using the Kruskall–Wallis and post-hoc test (α = 0.05). XRF analysis revealed that all of the glasses produced were within the calculated chemistry. The laser granulometry results confirmed that all glass powders had a similar grain size distribution before sintering, and the XRD investigation showed that all glasses had a characteristic amorphous structure without noticeable devitrification. G3 exhibited the best radiopacity result in compliance with ISO 6876, with a mean value of 4.06 ± 0.10 mm aluminum equivalent. G3 also showed the best sintering behavior among all of the laser parameters tested, without any statistical differences from the reference glass G1 (P > 0.05). Particularly in view of its bonding behavior to dental hard tissues, further research on the use of G3 as an endodontic laser-sinterable sealing material can therefore be strongly recommended.