High contrast optical imaging methods for image guided laser ablation of dental caries lesions

LaMantia, Nicole R.; Tom, Henry; Chan, Kenneth H.; Simon, Jacob C.; Darling, Cynthia L.; Fried, Daniel

doi:10.1117/12.2045683

Cited by 15 publications

(17 citation statements)

References 17 publications

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“…[18] Surface roughening can scatter light which may increase the reflectivity and confound image guided ablation, moreover it also can be aesthetically displeasing. [18] Therefore, it is important to choose laser scanning parameters that minimize surface roughening. The influence of varying the fluence and the spatial overlap of the laser pulses was also investigated.…”

Section: Resultsmentioning

confidence: 99%

A new sealed RF-excited CO₂laser for enamel ablation operating at 9.4μm with pulse duration of 26 μs

2016

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Several studies over the past 20 years have shown that carbon dioxide lasers operating at wavelengths between 9.3 and 9.6-μm with pulse durations near 20-μs are ideal for hard tissue ablation. Those wavelengths are coincident with the peak absorption of the mineral phase. The pulse duration is close to the thermal relaxation time of the deposited energy of a few microseconds which is short enough to minimize peripheral thermal damage and long enough to minimize plasma shielding effects to allow efficient ablation at practical rates. The desired pulse duration near 20-μs has been difficult to achieve since it is too long for transverse excited atmospheric pressure (TEA) lasers and too short for radio-frequency (RF) excited lasers for efficient operation. Recently, Coherent Inc. (Santa Clara, CA) developed the Diamond J5-V laser for microvia drilling which can produce laser pulses greater than 100-mJ in energy at 9.4-μm with a pulse duration of 26-μs and it can achieve pulse repetition rates of 3 KHz. We report the first results using this laser to ablate dental enamel. Efficient ablation of dental enamel is possible at rates exceeding 50-μm per pulse. This laser is ideally suited for the selective ablation of carious lesions.

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Section: Resultsmentioning

confidence: 99%

A new sealed RF-excited CO₂laser for enamel ablation operating at 9.4μm with pulse duration of 26 μs

2016

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“…Thus, an image-guided computer-controlled laser is ideal for selectively removing caries lesions. Previous work demonstrated that the CO 2 laser irradiated enamel does not interfere with the ability to image the tooth surface nor significantly distort the contrast between sound and carious dental hard tissues [7]. Furthermore, in past near-IR image-guided laser experiments, InGaAs cameras were successful in detecting lesion presence and guiding a CO 2 laser for lesion removal [8].…”

Section: Introductionmentioning

confidence: 99%

Selective ablation of carious lesions using an integrated multispectral near-IR imaging system and a novel 9.3-µm CO2 laser

Chan

Fried

2018

Lasers in Dentistry XXIV

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Previous studies have shown that reflectance imaging at wavelengths greater than 1200-nm can be used to image demineralization on tooth occlusal surfaces with high contrast and without the interference of stains. In addition, these near-IR imaging systems can be integrated with laser ablation systems for the selective removal of carious lesions. Higher wavelengths, such as 1950-nm, yield higher lesion contrast due to higher water absorption and lower scattering. In this study, a point-to-point scanning system employing diode and fiber lasers operating at 1450, 1860, 1880, and 1950-nm was used to acquire reflected light images of the tooth surface. Artificial lesions were imaged at these wavelengths to determine the highest lesion contrast. Near-IR images at 1880-nm were used to demarcate lesion areas for subsequent selective carious lesion removal using a new compact air-cooled CO2 laser prototype operating at 9.3-µm. The highest lesion contrast was at 1950-nm and the dual NIR/CO2 laser system selectively removed the simulated lesions with a mean loss of only 12-µm of sound enamel.

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“…CO 2 lasers (λ = 9.3–9.6-µm) have been shown to be well suited for caries removal and CO 2 laser pulses can be used to render dental enamel to be more resistant to further decay [7]. Previous work was done to show that the laser irradiated enamel does not interfere with the ability to image the tooth surface at near-IR wavelengths nor significantly distort the contrast between sound and demineralized dental hard tissues [8]. Typical dental lasers are operated by hand, which nullifies their capacity for high precision and selectivity.…”

Section: Introductionmentioning

confidence: 99%

Image-guided removal of interproximal lesions with a CO2 laser

Ngo

Chan

Lê

et al. 2018

Lasers in Dentistry XXIV

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Recent studies have shown that near-IR (NIR) imaging methods such as NIR reflectance can be used to image lesions on proximal surfaces, and optical coherence tomography (OCT) can be used to measure the depth of those lesions below the tooth surface. These imaging modalities can be used to acquire high contrast images of demineralized tooth surfaces, and 2-D and 3-D images can be extracted from this data. At NIR wavelengths longer than 1200-nm, there is no interference from stains and the contrast is only due to the increased light scattering of the demineralization. Previous studies have shown that image-guided laser ablation can be used to remove occlusal lesions, but its use for the removal of subsurface lesions on proximal surfaces has not been investigated. The objective of this study is to demonstrate that simultaneously scanned NIR and CO 2 lasers can be used to selectively remove natural and artificial interproximal caries lesions with minimal damage to sound tooth structure. In this study, images of simulated and natural interproximal lesions on extracted teeth were imaged using a digital microscope, a scanned 1460-nm superluminescent laser diode with an InGaAs detector and a cross polarization OCT system operating at 1300-nm. The lesions were subsequently removed with a CO 2 laser operating at 9.3-µm and the dental handpiece and the volume of sound tissue removed was compared.

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High contrast optical imaging methods for image guided laser ablation of dental caries lesions

Cited by 15 publications

References 17 publications

A new sealed RF-excited CO₂laser for enamel ablation operating at 9.4μm with pulse duration of 26 μs

A new sealed RF-excited CO₂laser for enamel ablation operating at 9.4μm with pulse duration of 26 μs

Selective ablation of carious lesions using an integrated multispectral near-IR imaging system and a novel 9.3-µm CO2 laser

Image-guided removal of interproximal lesions with a CO2 laser

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High contrast optical imaging methods for image guided laser ablation of dental caries lesions

Cited by 15 publications

References 17 publications

A new sealed RF-excited CO2laser for enamel ablation operating at 9.4μm with pulse duration of 26 μs

A new sealed RF-excited CO2laser for enamel ablation operating at 9.4μm with pulse duration of 26 μs

Selective ablation of carious lesions using an integrated multispectral near-IR imaging system and a novel 9.3-µm CO2 laser

Image-guided removal of interproximal lesions with a CO2 laser

Contact Info

Product

Resources

About

A new sealed RF-excited CO₂laser for enamel ablation operating at 9.4μm with pulse duration of 26 μs

A new sealed RF-excited CO₂laser for enamel ablation operating at 9.4μm with pulse duration of 26 μs