Noninvasive Temperature Measurement in Dental Materials Using Nd³⁺, Yb³⁺ Doped Nanoparticles Emitting in the Near Infrared Region

Abstract

In this work, the application of near infrared (NIR)‐emitting NaYbF4:1%Tm3+@NaLuF4:30%Nd3+ core–shell nanoparticles is reported for noninvasive probing and monitoring the temperature during photopolymerization of dental materials. When excited at 808 nm, the synthesized nanoparticles emit NIR photoluminescence (PL) with two distinctive peaks at 865 and 980 nm which correspond to radiative transitions from the doped Nd3+ and Yb3+ ions, respectively. Luminescence intensity ratio between these two bands is found to vary with temperature due to temperature‐dependent electronic excitation energy transfer between Nd3+ and Yb3+ ions at the core/shell interface. This finding allows luminescence ratiometric evaluation of the in situ temperature during photopolymerization of resin cement (doped with nanoparticles) in a veneer placement procedure. In addition, the NIR emission also enables PL imaging of the distribution of the adhesive under the veneer. The results highlight that rare‐earth ions–doped nanoparticles with both excitation and emission in the NIR spectral range are advantageous for both PL‐based nanothermometry and imaging due to the reduced attenuation of NIR light by dental ceramics.

KLaP4O12:Tb3+ Nanocrystals for Luminescent Thermometry in a Single-Band-Ratiometric Approach

“…Novel nanomaterials and methods of optical noncontact temperature readout in demanding or harsh conditions (such as biologically relevant media and variable pH or viscosity) are being increasingly developed. − A significant advantage of some of the proposed luminescent thermometers is their nanometric size because it enables application in the most challenging fields such as bioimaging, medical diagnostics, and microelectronics. Innovative application possibilities are investigated, and increasingly advanced results are presented in these fields. − However, in order to maintain the growth rate of luminescent thermometry popularity, not only material research but also methods to verify the theory of thermal phenomena occurring in nanothermometers should be developed. Understanding the thermally activated processes occurring in the investigated systems would enable a knowledgeable and purposeful design of appropriate materials doped with an optimal concentration of selected optically active ions for specific applications.…”

In Situ Ultraviolet Polymerization Using Upconversion Nanoparticles: Nanocomposite Structures Patterned by Near Infrared Light

“…It is worth also noting that the blue emission of Tm 3+ -doped UCNPs (peaked at ~450 and ~475 nm) are overlapping with the absorbance of common commercial photoinitiators used in dental adhesive systems. At the same time, light at 980 nm penetrates deeper through dental ceramics compared to blue light, allowing for the use of blue emission from Tm 3+ synthetized by Yb 3+ ions under 980 nm to cure UCNP-doped resins in dental applications [ 41 , 42 ].…”

Exploiting Nanomaterials for Optical Coherence Tomography and Photoacoustic Imaging in Nanodentistry

“…Another way where nanomaterials are important in nanodentistry is in dental materials. This requires new developments, which include rare-earth-doped nanomaterials, which can be simultaneously used for imaging, temperature measurements and curing, using, for instance, photodynamic therapy [92]. Antibacterial nanotherapy is also an interesting field of research.…”