A numerical model for temperature distribution and thermal damage calculations in teeth exposed to a CO2 laser

Sagi, A. M.; Segal, Tuvia; Dagan, Jacob

doi:10.1016/0025-5564(84)90002-6

Cited by 14 publications

(6 citation statements)

References 11 publications

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“…Subsurface thermocouple measurements, simulations of heat conduction, and histological examinations during laser irradiation show that the extent of pulpal heating is determined by the rate of deposition of the laser energy in the tooth, the distance from the laser spot to the pulp, and the rate of energy loss from the tooth. [34][35][36][37] By using the shorter laser pulse we are modifying a 1 mm spot size on the enamel surface with a total absorbed energy delivered of only 20-100 mJ for 5-25 laser pulses ͑0.5 J/cm 2 ) versus 100-2500 mJ in our previous studies utilizing 100 s 9.6 m laser pulses ͑2.5 J/cm 2 ͒. Note that other groups report the use of continuous wave CO 2 and argon ion lasers for caries prevention and they utilize absorbed fluences in the 100-200 J/cm 2 range, factors of 200-400 times higher than what we report in this study.…”

Section: Infrared Spectroscopy and Caries Prevention Studiesmentioning

confidence: 99%

Dental hard tissue modification and removal using sealed transverse excited atmospheric-pressure lasers operating at λ=9.6 and 10.6 μm

et al. 2001

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Pulsed CO(2) lasers have been shown to be effective for both removal and modification of dental hard tissue for the treatment of dental caries. In this study, sealed transverse excited atmospheric pressure (TEA) laser systems optimally tuned to the highly absorbed 9.6 microm wavelength were investigated for application on dental hard tissue. Conventional TEA lasers produce an initial high energy spike at the beginning of the laser pulse of submicrosecond duration followed by a long tail of about 1-4 micros. The pulse duration is well matched to the 1-2 micros thermal relaxation time of the deposited laser energy at 9.6 microm and effectively heats the enamel to the temperatures required for surface modification at absorbed fluences of less than 0.5 J/cm(2). Thus, the heat deposition in the tooth and the corresponding risk of pulpal necrosis from excessive heat accumulation is minimized. At higher fluences, the high peak power of the laser pulse rapidly initiates a plasma that markedly reduces the ablation rate and efficiency, severely limiting applicability for hard tissue ablation. By lengthening the laser pulse to reduce the energy distributed in the initial high energy spike, the plasma threshold can be raised sufficiently to increase the ablation rate by an order of magnitude. This results in a practical and efficient CO(2) laser system for caries ablation and surface modification.

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Section: Infrared Spectroscopy and Caries Prevention Studiesmentioning

confidence: 99%

Dental hard tissue modification and removal using sealed transverse excited atmospheric-pressure lasers operating at λ=9.6 and 10.6 μm

et al. 2001

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“…Pulp tissue has been reported to be sensitive and also vulnerable to temperature (Sagi et al . , Jafarzadeh et al . , Lin et al .…”

Section: Introductionmentioning

confidence: 99%

“…The human tooth is subjected to daily thermal loading due to consumption of hot liquids and foods (Boehm 1972, Jacobs et al 1973) that may cause thermally induced damage (Brown et al 1972). Pulp tissue has been reported to be sensitive and also vulnerable to temperature (Sagi et al 1984, Jafarzadeh et al 2008, Lin et al 2010. Zach & Cohen (1965) reported that a monkey's tooth thermally loaded from the outer surface of the enamel resulted in a temperature increase of 5.5°C as diagnosed by bead-type thermistors that caused irreversible pulp damage.…”

Section: Introductionmentioning

confidence: 99%

“…However, the distribution of the temperature through the intact tooth has not been fully studied. Sagi et al (1984) developed a preliminary model to evaluate the temporal and spatial temperature distribution and examine its consequent damage to teeth exposed to a CO 2 laser beam. Due to the complexity of the geometry of the tooth tissues and their different properties, the precise prediction of the distribution of temperature through them requires numerical methods (Ana et al 2008).…”

Section: Introductionmentioning

confidence: 99%

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Thermal analysis of the intact mandibular premolar: a finite element analysis

et al. 2013

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“…Fresh dentin (human -0.49% ± 0.27) contracted on heating under dry condition. Sagi et al [10] considering a homogeneous cube for the tooth and calculated the temperature distribution of the tooth under laser beams. Malmstrom et al [11] inspected experimentally the effects of repetition rate of CO 2 laser pulses on the temperature of pulp chamber.…”

Section: Introductionmentioning

confidence: 99%

Stress behaviour across human tooth by temperature gradient resulting of laser irradiation

Falahatkar

Nouri-Borujerdi

Najafi

2020

JMES

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The authors report the simulation of temperature distribution and thermally induced stress in the premolar tooth under ND-YAG pulsed laser beam. The Three-Phase-Lag (TPL) non-Fourier model is proposed to describe the heat conduction in the human tooth with nonhomogeneous inner structures. A premolar tooth comprising enamel, dentin, and pulp with real shapes and thicknesses are considered and a numerical method of finite difference was adopted to solve the time-dependent TPL bio-heat transfer, strain and stress equations. The surface heating scheme is applied for simulation of laser therapy. The aim of this laser therapy is that the temperature of pulp reaches to 47oC. The results are achieved as a function of laser heat flux showed when laser beam is irradiated downward (from the top of the tooth), the temperature and thermally induced stress increase as a function of time. The temperature increment is high on the top layers of tooth that is a result of strong absorption of beams by enamel. The thermal stress and strain in the enamel and dentin layers are more than the pulp layer that is a result of weak thermal expansion of them proportional to the pulp layer.

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A numerical model for temperature distribution and thermal damage calculations in teeth exposed to a CO2 laser

Cited by 14 publications

References 11 publications

Dental hard tissue modification and removal using sealed transverse excited atmospheric-pressure lasers operating at λ=9.6 and 10.6 μm

Dental hard tissue modification and removal using sealed transverse excited atmospheric-pressure lasers operating at λ=9.6 and 10.6 μm

Thermal analysis of the intact mandibular premolar: a finite element analysis

Stress behaviour across human tooth by temperature gradient resulting of laser irradiation

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