Fs‐laser ablation of teeth is temperature limited and provides information about the ablated components

Abstract

The goal of this work is to investigate the thermal effects of femtosecond laser (fs-laser) ablation for the removal of carious dental tissue. Additional studies identify different tooth tissues through femtosecond laser induced breakdown spectroscopy (fsLIBS) for the development of a feedback loop that could be utilized during ablation in a clinical setting. Scanning Election Microscope (SEM) images reveal that minimal morphological damages are incurred at repetition rates below the carbonization threshold of each tooth tissue. Thermal studies measure the temperature distribution and temperature decay during laser ablation and after laser cessation, and demonstrate that repetition rates at or below 10kHz with a laser fluence of 40 J/cm would inflict minimal thermal damage on the surrounding nerve tissues and provide acceptable clinical removal rates. Spectral analysis of the different tooth tissues is also conducted and differences between the visible wavelength fsLIBS spectra are evident, though more robust classification studies are needed for clinical translation. These results have initiated a set of precautionary recommendations that would enable the clinician to utilize femtosecond laser ablation for the removal of carious lesions while ensuring that the solidity and utility of the tooth remain intact.

Feasibility Study on Discrimination of Neo-plastic and Non-Neoplastic Gastric Tissues Using Spark Discharge Assisted Laser Induced Breakdown Spectroscopy

“…Emissions of excited atoms, ions, and molecules in this plasma are recorded as a spectrum and analyzed for atomic identification of the sample. In recent years, this technique is mostly used for analysis of different tissues, including hard tissues such as hair, 11 nails [12][13][14][15][16][17][18] and teeth [19][20][21][22] and soft tissues such as blood, 23 cervical, 24 liver 25 and colorectal tissues. 26 What sets this method apart from other conventional methods is the convenience of sample preparation, higher speed of performance and no direct connection with samples especially contaminant materials.…”

Influence of environmental conditions in bovine bone ablation by ultrafast laser

“…Over the past two decades, a number of studies have looked into replacing mechanical surgical tools by lasers when cutting/drilling bone and/or cartilage . Advantages of using laser ablation over mechanical cutting include more precise cuts, minimal mechanical stress and thermal collateral damage, the ability to work without physical contact and integration with real‐time optical feedback . Many studies have been carried out to characterize bone ablation using infrared (IR) lasers with long pulse duration (nanoseconds to microseconds), for example, CO 2 ( λ = 9.6 μm), Er:YAG ( λ = 2.94 μm), Ho:YAG ( λ = 2.1 μm) and Nd:YAG ( λ = 1.06 μm) .…”

“…Advantages of using laser ablation over mechanical cutting include more precise cuts, minimal mechanical stress and thermal collateral damage, the ability to work without physical contact and integration with real‐time optical feedback . Many studies have been carried out to characterize bone ablation using infrared (IR) lasers with long pulse duration (nanoseconds to microseconds), for example, CO 2 ( λ = 9.6 μm), Er:YAG ( λ = 2.94 μm), Ho:YAG ( λ = 2.1 μm) and Nd:YAG ( λ = 1.06 μm) . It was shown that long‐pulse IR laser ablation may cause melting, carbonizing, cracking and fissuring of hard tissue .…”

Ultrafast dynamics of hard tissue ablation using femtosecond‐lasers

“…One advantage of the ultrashort pulse durations is that intensity levels can be achieved which enable non‐linear absorption leading to ablation of virtually all types of hard tissue, thus the wavelength of the laser source may not be selected according to the optical properties of the tissue . The main advantage of ultrashort pulse laser application is however that the treated tissue shows no significant thermal side effects, such as melting or cracking, as demonstrated for the ablation of, for example, bone , dental tissue , or urinary calculi . Ultrafast laser reduce thermal side effects, because the thermal penetration depth is in the order of the ablation depth, which means that most of the heated material is ablated.…”