&lt;title&gt;Mechanism of laser-induced solubility reduction of dental enamel&lt;/title&gt;

Featherstone, J.D.B.; Fried, Daniel; Bitten, Eric R.

doi:10.1117/12.273578

Cited by 52 publications

(50 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These desirable changes are likely to be associated with higher bond strengths to restorative materials and increased resistance to acid dissolution [30,35]. Using SR-FTIR, we acquired wellresolved spectra from the rough surfaces of the interior of the ablation craters with a spatial resolution of 10 mm.…”

Section: Discussionmentioning

confidence: 99%

“…We suspect that the added layer of water aids in preventing the formation of fused areas of the non-apatitic phases and results in a more desirable surface morphology. The modified enamel within the crater are lacking the two carbonate bands located near 1400 cm À1 , indicative of the formation of the desired purer phase hydroxyapatite with fewer chemical defects [20,30,35].…”

Section: Sr-ftirmentioning

confidence: 99%

See 1 more Smart Citation

Mechanism of water augmentation during IR laser ablation of dental enamel

et al. 2002

Self Cite

View full text Add to dashboard Cite

Background and Objectives: The mechanism of water augmentation during IR laser ablation of dental hard tissues is controversial and poorly understood. The influence of an optically thick applied water layer on the laser ablation of enamel was investigated at wavelengths in which water is a primary absorber and the magnitude of absorption varies markedly. Study Design/Materials and Methods: Q-switched and free running Er: YSGG (2.79 mm) and Er:YAG (2.94 mm), free running Ho:YAG and 9.6 mm TEA CO 2 laser systems were used to produce linear incisions in dental enamel with and without water. Synchrotron-radiation IR spectromicroscopy with the Advanced Light Source at Lawrence Berkeley National Laboratory was used to determine the chemical changes across the laser ablation profiles with a spatial resolution of 10-mm. Results: The addition of water increased the rate of ablation and produced a more desirable surface morphology during enamel ablation with all the erbium systems. Moreover, ablation was markedly more efficient for Q-switched (0.15 microsecond) versus free-running (150 microsecond) erbium laser pulses with the added water layer. Although the addition of a thick water layer reduced the rate of ablation during CO 2 laser ablation, the addition of the water removed undesirable deposits of non-apatite mineral phases from the crater surface. IR spectromicroscopy indicates that the chemical composition of the crater walls deviates markedly from that of hydroxyapatite after Er:YAG and CO 2 laser irradiation without added water. New mineral phases were resolved that have not been previously observed using conventional IR spectroscopy. There was extensive peripheral damage after irradiation with the Ho:YAG laser with and without added water without effective ablation of enamel. Conclusions: We postulate that condensed mineral phases from the plume are deposited along the crater walls after repetitive laser pulses and such non-apatitic phases interfere with subsequent laser pulses during IR laser irradiation reducing the rate and efficiency of ablation. The ablative recoil associated with the displacement and vaporization of the applied water layer removes such loosely adherent phases maintaining efficient ablation during multiple pulse irradiation.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Sr-ftirmentioning

confidence: 99%

Mechanism of water augmentation during IR laser ablation of dental enamel

et al. 2002

Self Cite

View full text Add to dashboard Cite

show abstract

“…58 Currently, it is believed that the decrease in enamel solubility after laser treatments is due to stringent changes in the infrastructure, such as water and carbonate content reduction, increase in hydroxyl ions, pyrophosphates formation, and protein decomposition. 20,21,24 Another possibility would be to change and possibly destroy the organic material found in the interprismatic space. The laser irradiation can create such microspaces that can act as sites of deposition of ions 50 .…”

Section: De Sant'anna Et Almentioning

confidence: 99%

“…[20][21][22][23] Since the 1960s, it has been consistently demonstrated that high power lasers, under certain conditions, can reduce the rate of subsurface demineralization in the enamel, by altering the crystallinity, acid solubility, and permeability of enamel. [24][25][26] Nevertheless, the real mechanisms of caries inhibition by lasers remain unclear.…”

mentioning

confidence: 99%

Dental Enamel Irradiated with Infrared Diode Laser and Photo-Absorbing Cream: Part 2—EDX Study

Sant'Anna

Santos

Soares

et al. 2009

Photomedicine and Laser Surgery

View full text Add to dashboard Cite

Objective: The effects of laser-induced compositional changes on the enamel were investigated by energydispersive X-ray fluorescence spectrometry (m-EDX). After cariogenic challenge, we administered treatment of low-level infrared diode laser and a photo-absorbing cream (used to intensify the superficial light absorption). Background Data: Dental caries is considered the most prevalent oral disease. A simple and noninvasive caries preventive regimen is treating tooth enamel with a laser, either alone or in combination with fluoride, which reduces enamel solubility and dissolution rates. High power lasers are still not widely used in private practice. Low-power near-infrared lasers may be an alternative approach. Energy-dispersive m-EDX is a versatile and nondestructive spectroscopic technique that allows for a qualitative and quantitative elemental analysis of inorganic enamel components, such as calcium and phosphorus. Materials and Methods: Twenty-four extracted or exfoliated caries-free deciduous molars were divided into six groups: 1) control group (CTR-no treatment); 2) infrared laser treatment (L) (l ¼ 810 nm, 100 mW=cm 2 , 90 sec, 4.47 J=cm 2 , 9 J); 3) infrared laser irradiation and photo-absorbing agent (CL); 4) photo-absorbing agent alone (C); 5) infrared laser irradiation and fluoridated photo-absorbing agent (FCL); and 6) fluoridated photo-absorbing agent alone (FC). Samples were analyzed using m-EDX after two sets of treatments and pH cycling cariogenic challenges. Results: The CL group showed statistically significant increases in calcium and phosphorus (wt%) compared with the CTR group. The Ca=P ratio was similar in the FCL and CTR groups. There was a significant laser-induced reduction compared with the CTR group, and there was a possible modification of the organic balance content in enamel treated with laser and cream. Conclusion: m-EDX may be able to detect compositional changes in mineral phases of lased enamel under cariogenic challenge. Our results suggest that with a combined laser and photo-absorbing agent (CL) treatment, there was a possible disorganization of organic content in the tooth enamel with hydroxyapatite crystal reordering and reorganization.

show abstract

“…[1][2][3][4][5][6][7] Carbon dioxide laser wavelengths of 9.3 and 9.6-μm have the strongest absorption in dental hard tissues and a pulse duration in the microsecond range is well-matched to the thermal relaxation time of the absorbed laser energy near the tooth surface for those wavelengths. Moreover, other studies have indicated that topical fluoride treatments can work synergistically with the laser treatment to further enhance its inhibitory effect [8][9][10][11] .…”

Section: Introductionmentioning

confidence: 99%

Imaging laser irradiated enamel surfaces with polarization sensitive optical coherence tomography

2008

Self Cite

View full text Add to dashboard Cite

Several studies have shown that lasers can be used to modify the surface morphology and chemical composition of tooth enamel to render it less soluble. Other studies have shown that Polarization Sensitive Optical Coherence Tomography (PS-OCT) can be used to non-destructively measure the efficacy of fluoride in inhibiting the development of artificial caries lesions. The purpose of this study was to determine if PS-OCT can be used to measure inhibition of enamel demineralization after CO 2 laser irradiation. Polarized light microscopy and microradiography were used to measure lesion severity on histological thin sections for comparison. PS-OCT was able to measure a significant reduction in the integrated reflectivity due to inhibition by the laser even though the laser modification of the enamel surface caused a slight increase in reflectivity. This study shows that the PS-OCT is well-suited for in vivo measurements of caries inhibition after laser treatments. INTRODUCTIONSeveral studies over the past thirty years have indicated that lasers can be used to thermally modify the chemical composition of dental enamel to render it more resistant to acid dissolution and potentially more resistant to dental caries. [1][2][3][4][5][6][7] Carbon dioxide laser wavelengths of 9.3 and 9.6-μm have the strongest absorption in dental hard tissues and a pulse duration in the microsecond range is well-matched to the thermal relaxation time of the absorbed laser energy near the tooth surface for those wavelengths. Moreover, other studies have indicated that topical fluoride treatments can work synergistically with the laser treatment to further enhance its inhibitory effect [8][9][10][11] . Current methods of evaluating the efficacy of chemical and thermal methods of anti-caries agents requires teeth scheduled for extraction followed by assessment with either microradiography, microhardness or polarized light microscopy. Such methods require thin sectioning of the extracted tooth, hence the need to carry out studies on teeth scheduled for extraction. One major limitation of this approach is that these studies must be limited in duration to a maximum of a few months and that natural caries lesions, particularly in occlusal surfaces, require a more extended time for development. One promising new method for the assessment of early caries lesions "in vivo" is polarization sensitive optical coherence tomography (PS-OCT), which has been * daniel.fried@ucsf.edu, 415-502-6641. Optical coherence tomography (OCT) is a noninvasive technique for creating cross-sectional images of internal biological structure 14,15 . We have demonstrated that polarizationsensitive depth-resolved reflectivity measurements can be used to measure the severity of natural and artificial lesions on extracted teeth in the laboratory [16][17][18][19][20] . The reflectance at the air-enamel interface of the tooth surface is very strong due to the high refractive index of enamel, n=1.63. It poses a particular challenge for OCT because the surface reflectivity ...

show abstract

<title>Mechanism of laser-induced solubility reduction of dental enamel</title>

Cited by 52 publications

References 0 publications

Mechanism of water augmentation during IR laser ablation of dental enamel

Mechanism of water augmentation during IR laser ablation of dental enamel

Dental Enamel Irradiated with Infrared Diode Laser and Photo-Absorbing Cream: Part 2—EDX Study

Imaging laser irradiated enamel surfaces with polarization sensitive optical coherence tomography

Contact Info

Product

Resources

About