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Hajizadeh H, Nemati-Karimooy A, Babaee-Rishkhori P. Effect of Erbium:Yttrium-Aluminum-Garnet Laser Combined with Mineralizing Agents on Microhardness of Demineralized Dentin. Eur J Dent 2019; 13:11-16. [PMID: 31170757 PMCID: PMC6635968 DOI: 10.1055/s-0039-1688730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Objective
The aim of this study was to assess the combined effect of erbium:yttrium-aluminum-garnet (Er:YAG) laser and mineralizing agents including casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and fluoride in improving the resistance of demineralized dentin at new demineralization process.
Materials and Methods
One hundred and twenty healthy dentin surfaces were prepared and demineralized using acidic solutions. Primary microhardness was measured (h1), and samples were randomly divided into six groups. Each group received a different protocol as follows: Group A (control group): no additional treatment, Group B: applying a fluoridated gel, Group C: applying a CPP-ACP-containing cream, Group D: irradiation of Er:YAG laser, Group E: irradiation of Er:YAG laser combined with the application of a fluoridated agent, and Group F: irradiation of Er:YAG laser combined with the application of CPP-ACP-containing cream. Microhardness values were measured afterward (h2). Then, all the groups were re-exposed to acidic solution, and microhardness was measured for the third time (h3). The microhardness data were analyzed using analysis of variance and Scheffe's post hoc test.
Results
Although application of mineralizing agents increased the microhardness of demineralized dentin in comparison with the control group, no significant difference was observed using two agents. Comparison of laser groups showed an increase in microhardness only after the irradiation of Er:YAG laser combined with the application of a fluoridated agent. Demineralizing process reduced the microhardness values in all the groups, but the application of a CPP-ACP agent caused the least reduction among the laser irradiated groups. Comparison of hardness changes at the beginning and end of the experiment did not show any significant differences between the groups.
Conclusion
Comparison of treatment modalities used in this study exhibited that fluoride had the greatest impact on dentin resistance. Laser irradiation on demineralized dentin did not increase the hardness or resistance to acidic attacks.
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Affiliation(s)
- Hila Hajizadeh
- Department of Restorative and Cosmetic Dentistry, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.,Dental Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Atefeh Nemati-Karimooy
- Department of Restorative and Cosmetic Dentistry, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.,Dental Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
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Rechmann P, Rechmann BMT, Groves WH, Le CQ, Rapozo-Hilo ML, Kinsel R, Featherstone JDB. Caries inhibition with a CO2 9.3 μm laser: An in vitro study. Lasers Surg Med 2016; 48:546-54. [PMID: 27075245 DOI: 10.1002/lsm.22497] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2016] [Indexed: 11/09/2022]
Abstract
BACKGROUND AND OBJECTIVES The caries preventive effects of different laser wavelengths have been studied in the laboratory as well as in pilot clinical trials. The objective of this in vitro study was to evaluate whether irradiation with a new 9.3 μm microsecond short-pulsed CO2 -laser could enhance enamel caries resistance with and without additional fluoride applications. STUDY DESIGN/MATERIALS AND METHODS One hundred and one human tooth enamel samples were divided into seven groups. Each group was treated with different laser parameters (CO2 -laser, wavelength 9.3 μm, 43 Hz pulse-repetition rate, pulse duration between 3 µs at 1.5 mJ/pulse to 7 µs at 2.9 mJ/pulse). A laboratory pH-cycling model followed by cross-sectional microhardness testing determined the mean relative mineral loss delta Z (ΔZ) for each group to assess caries inhibition in tooth enamel by the CO2 9.3 µm short-pulsed laser irradiation. The pH-cycling was performed with or without additional fluoride. RESULTS The non-laser control groups with additional fluoride had a relative mineral loss (ΔZ, vol% × µm) that ranged between 646 ± 215 and 773 ± 223 (mean ± SD). The laser irradiated and fluoride treated samples had a mean ΔZ ranging between 209 ± 133 and 403 ± 245 for an average 55% ± 9% reduction in mineral loss (ANOVA test, P < 0.0001). Increased mean mineral loss (ΔZ between 1166 ± 571 and 1339 ± 347) was found for the non-laser treated controls without additional fluoride. In contrast, the laser treated groups without additional fluoride showed a ΔZ between 470 ± 240 and 669 ± 209 (ANOVA test, P < 0.0001) representing an average 53% ± 11% reduction in mineral loss. Scanning electron microscopical assessment revealed that 3 µs pulses did not markedly change the enamel surface, while 7 µs pulses caused some enamel ablation. CONCLUSION The CO2 9.3 µm short-pulsed laser energy renders enamel caries resistant with and without additional fluoride use. The observed enhanced acid resistance occurred with the laser irradiation parameters used without obvious melting of the enamel surface as well as after irradiation with energies causing cutting of the enamel. Lasers Surg. Med. 48:546-554, 2016. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.
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Affiliation(s)
- Peter Rechmann
- Department of Preventive and Restorative Dental Sciences, University of California at San Francisco, School of Dentistry, 707 Parnassus Avenue, San Francisco, California, 94143
| | - Beate M T Rechmann
- Department of Preventive and Restorative Dental Sciences, University of California at San Francisco, School of Dentistry, 707 Parnassus Avenue, San Francisco, California, 94143
| | - William H Groves
- Convergent Dental, Inc., 2 Vision Drive, Natick, Massachusetts, 01760
| | - Charles Q Le
- Department of Preventive and Restorative Dental Sciences, University of California at San Francisco, School of Dentistry, 707 Parnassus Avenue, San Francisco, California, 94143
| | - Marcia L Rapozo-Hilo
- Department of Preventive and Restorative Dental Sciences, University of California at San Francisco, School of Dentistry, 707 Parnassus Avenue, San Francisco, California, 94143
| | - Richard Kinsel
- Department of Preventive and Restorative Dental Sciences, University of California at San Francisco, School of Dentistry, 707 Parnassus Avenue, San Francisco, California, 94143
| | - John D B Featherstone
- Department of Preventive and Restorative Dental Sciences, University of California at San Francisco, School of Dentistry, 707 Parnassus Avenue, San Francisco, California, 94143
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Rechmann P, Charland DA, Rechmann BMT, Le CQ, Featherstone JDB. In-vivo occlusal caries prevention by pulsed CO2 -laser and fluoride varnish treatment--a clinical pilot study. Lasers Surg Med 2013; 45:302-10. [PMID: 23737079 DOI: 10.1002/lsm.22141] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2013] [Indexed: 11/08/2022]
Abstract
BACKGROUND AND OBJECTIVES High caries prevalence in occlusal pits and fissures warrants novel prevention methods. An 86% reduction in dental enamel smooth surface demineralization in-vivo following short-pulsed 9.6 µm-CO(2) -laser irradiation was recently reported. The objective of this study was to conduct a blinded 12-month-pilot clinical trial of occlusal pit and fissure caries inhibition using the same CO(2) -laser irradiation conditions. STUDY DESIGN/MATERIALS AND METHODS Twenty subjects, average age 14 years, were recruited. At baseline, second molars were randomized into test and control groups, assessed by International Caries Detection & Assessment System (ICDAS-II), SOPROLIFE light-induced fluorescence evaluator in daylight and blue-fluorescence mode and DIAGNOdent. An independent investigator irradiated test molars with a CO(2) -laser, wavelength 9.6 µm, pulse-duration 20 µs, pulse-repetition-rate 20 Hz, beam diameter 800 µm, average fluence 4.5 ± 0.5 J/cm(2), 20 laser pulses per spot. At 3-, 6- and 12-month recall teeth were assessed by ICDAS, SOPROLIFE and DIAGNOdent. All subjects received fluoride varnish applications at baseline and 6-month recall. RESULTS All subjects completed the 3-month, 19 the 6-month and 16 the 12-month recall. At all recalls average ICDAS scores had decreased for the test and increased for the control fissures (laser vs. control, 3-month: -0.10 ± 0.14, 0.30 ± 0.18, P > 0.05; 6-month: -0.26 ± 0.13, 0.47 ± 0.16, P = 0.001; 12-month: -0.31 ± 0.15, 0.75 ± 0.17, P < 0.0001; mean ± SE, unpaired t-test) being statistically significantly different at 6- and 12-month recalls. SOPROLIFE daylight evaluation revealed at 6- and 12-months statistically significant differences in changes between baseline and recall for test and control molars, respectively (laser vs. control, 6-month: 0.22 ± 0.13, 0.17 ± 0.09, P = 0.02; 12-month: 0.28 ± 0.19, 0.25 ± 0.17, P = 0.03). For SOPROLIFE blue-fluorescence evaluation mean changes in comparison to baseline for the control and the laser treated teeth were also statistically significant for the 6- and 12-month recall. CONCLUSION Specific microsecond short-pulsed 9.6 µm CO(2) -laser irradiation markedly inhibits caries progression in pits and fissures in comparison to fluoride varnish alone over 12 months.
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Affiliation(s)
- Peter Rechmann
- Department of Preventive and Restorative Dental Sciences, School of Dentistry, University of California at San Francisco, San Francisco, CA 94143, USA.
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Fornaini C, Merigo E, Vescovi P, Lagori G, Rocca J. Use of laser in orthodontics: applications and perspectives. Laser Ther 2013; 22:115-24. [PMID: 24155556 DOI: 10.3136/islsm.22.115] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 06/04/2013] [Indexed: 11/03/2022]
Abstract
Laser technology got in these years a more and more important role in modern dentistry and, recently, also in orthodontics was proposed the utilization of laser devices. The aim of this work is to describe the utilization of this technology both in soft and hard oral tissues to improve orthodontic treatment. Several cases, with different wavelengths (532, 810, 980, 1064, 2940 and 10600 nm) and in different times of the treatment (before, during and after) are presented. All the cases reported showed, according to the literature, that the use of the laser related to orthodontic treatment offers several advantages when compared with conventional methods. In the soft tissues surgery it allows to reduce or eliminate the use of anesthetic injection, to avoid use of sutures and to bond bracket in dry enamel; associated with orthophosphoric acid, it gives a stronger adhesion of the brackets to the enamel and, in the case of porcelain brackets, it detaches them without damages; at low power (LLLT) it permits to control the pain of the first period after bonding and, by increasing the speed of teeth movement in the bone, reduces the time of the treatment.
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Affiliation(s)
- C Fornaini
- Oral Medicine and Laser-Assisted Surgery Unit, Faculty of Medicine, University of Parma, Viale Antonio Gramsci, 14, 43126 Parma, Italy ; Faculty of Odontology, University Hospital "St. Roch", University of Nice-Sophia Antipolis, 5, rue Pierre Devoluy, 06006 Nice, France
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Fornaini C, Merigo E, Vescovi P, Lagori G, Rocca J. Use of laser in orthodontics: applications and perspectives. Laser Ther 2013. [PMID: 24155556 DOI: 10.5978/islsm.13-or-10] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Laser technology got in these years a more and more important role in modern dentistry and, recently, also in orthodontics was proposed the utilization of laser devices. The aim of this work is to describe the utilization of this technology both in soft and hard oral tissues to improve orthodontic treatment. Several cases, with different wavelengths (532, 810, 980, 1064, 2940 and 10600 nm) and in different times of the treatment (before, during and after) are presented. All the cases reported showed, according to the literature, that the use of the laser related to orthodontic treatment offers several advantages when compared with conventional methods. In the soft tissues surgery it allows to reduce or eliminate the use of anesthetic injection, to avoid use of sutures and to bond bracket in dry enamel; associated with orthophosphoric acid, it gives a stronger adhesion of the brackets to the enamel and, in the case of porcelain brackets, it detaches them without damages; at low power (LLLT) it permits to control the pain of the first period after bonding and, by increasing the speed of teeth movement in the bone, reduces the time of the treatment.
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Affiliation(s)
- C Fornaini
- Oral Medicine and Laser-Assisted Surgery Unit, Faculty of Medicine, University of Parma, Viale Antonio Gramsci, 14, 43126 Parma, Italy ; Faculty of Odontology, University Hospital "St. Roch", University of Nice-Sophia Antipolis, 5, rue Pierre Devoluy, 06006 Nice, France
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Lorenzo MC, Portillo M, Moreno P, Montero J, Castillo-Oyagüe R, García A, Albaladejo A. In vitro analysis of femtosecond laser as an alternative to acid etching for achieving suitable bond strength of brackets to human enamel. Lasers Med Sci 2013; 29:897-905. [DOI: 10.1007/s10103-013-1278-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 01/28/2013] [Indexed: 05/27/2023]
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Rechmann P, Fried D, Le CQ, Nelson G, Rapozo-Hilo M, Rechmann BMT, Featherstone JDB. Caries inhibition in vital teeth using 9.6-μm CO2-laser irradiation. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:071405. [PMID: 21806251 PMCID: PMC3144970 DOI: 10.1117/1.3564908] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 11/26/2010] [Accepted: 12/03/2010] [Indexed: 05/31/2023]
Abstract
The aim of this study was to test the hypothesis that in a short-term clinical pilot trial short-pulsed 9.6 μm CO(2)-laser irradiation significantly inhibits demineralization in vivo. Twenty-four subjects scheduled for extraction of bicuspids for orthodontic reasons (age 14.9 ± 2.2 years) were recruited. Orthodontic brackets were placed on bicuspids (Transbond XT, 3M). An area next to the bracket was irradiated with a CO(2)-laser (Pulse System Inc, Los Alamos, New Mexico), wavelength 9.6 μm, pulse duration 20 μs, pulse repetition rate 20 Hz, beam diameter 1100 μm, average fluence 4.1 ± 0.3J∕cm(2), 20 laser pulses per spot. An adjacent nonirradiated area served as control. Bicuspids were extracted after four and twelve weeks, respectively, for a quantitative assessment of demineralization by cross-sectional microhardness testing. For the 4-week arm the mean relative mineral loss ΔZ (vol% × μm) for the laser treated enamel was 402 ± 85 (mean ± SE), while the control showed significantly higher mineral loss (ΔZ 738 ± 131; P = 0.04, t-test). The difference was even larger after twelve weeks (laser arm ΔZ 135 ± 98; control 1067 ± 254; P = 0.002). The laser treatment produced 46% demineralization inhibition for the 4-week and a marked 87% inhibition for the 12-week arm. This study shows, for the first time in vivo, that the short-pulsed 9.6 μm CO(2)-laser irradiation successfully inhibits demineralization of tooth enamel in humans.
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Affiliation(s)
- Peter Rechmann
- University of California at San Francisco, Department of Preventive and Restorative Dental Sciences, School of Dentistry, 707 Parnassus Avenue, San Francisco, California 94143, USA.
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Guimarães GS, Morais LSD, Elias CN, Pérez CADC, Bolognese AM. Análise química e morfológica do esmalte dentário humano tratado com laser argônio durante a colagem ortodôntica. Dental Press J Orthod 2011. [DOI: 10.1590/s2176-94512011000200013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
INTRODUÇÃO: as principais utilizações do laser argônio na Ortodontia são a redução do tempo de polimerização durante a colagem ortodôntica e o aumento da resistência à cárie do esmalte dentário. OBJETIVO: o objetivo deste trabalho foi avaliar as alterações químicas e morfológicas do esmalte dentário humano tratado com laser argônio nos parâmetros da colagem ortodôntica. MÉTODOS: quinze primeiros pré-molares hígidos, extraídos por indicação ortodôntica, foram selecionados e seccionados no sentido do longo eixo em dois segmentos iguais. Uma metade de cada elemento dentário foi tratada e a outra permaneceu sem tratamento. Um total de 30 amostras foi analisado, criando o grupo laser (n = 15) e o grupo controle (n = 15). O tratamento foi feito com laser argônio com 250mW de potência por 5 segundos, com densidade de energia de 8J/cm². RESULTADOS: a análise de difração de raios X demonstrou duas fases em ambos os grupos, as fases apatita e monetita. A redução da fase monetita foi significativa após o tratamento com laser, sugerindo maior cristalinidade. A análise de Espectroscopia de Energia Dispersiva (EDS) indicou aumento na razão cálcio-fósforo no grupo laser, compatível com a diminuição da fase monetita. A morfologia superficial do esmalte dentário apresentou-se mais lisa após o tratamento com laser argônio. CONCLUSÕES: o aumento de cristalinidade e a lisura superficial do esmalte no grupo laser são fatores sugestivos de aumento de resistência à cárie no esmalte dentário.
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Vlacic J, Meyers IA, Walsh LJ. Laser-activated fluoride treatment of enamel as prevention against erosion. Aust Dent J 2007; 52:175-80. [PMID: 17969284 DOI: 10.1111/j.1834-7819.2007.tb00485.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Erosion is the loss of dental hard tissues from an acidic challenge, often resulting in exposure of dentinal tubules and hypersensitivity to environmental stimuli. Laser-activated fluoride (LAF) therapy with 488nm laser energy has been shown previously to increase the resistance of human enamel and dentine to acid dissolution. The aims of this study were to investigate the action spectrum of LAF in protecting tooth enamel from softening in response to an erosive challenge, and to examine for any temperature change with the treatment. MATERIALS AND METHODS Buccal and lingual surfaces of extracted sound molar and premolar teeth were used to prepare matched pairs of enamel slabs (N = 10 per group). After application of 1.23% neutral sodium fluoride gel (12 300ppm F ion), slab surfaces were lased with 488, 514.5, 532, 633, 670, 830 or 1064nm wavelength (energy density 15J/cm(-2); spot size 5mm), then exposed to an erosive challenge (1.0M HCI for five minutes). The Vicker's hardness number (VHN) was recorded before fluoride gel application and again following the acid challenge. Negative controls did not receive laser exposure. RESULTS All wavelengths of laser light examined provided a protective LAF effect against softening, compared with the negative control surfaces. CONCLUSION From these findings, we conclude that the action spectrum of the LAF effect extends across the visible spectrum, providing protection to dental enamel from an erosive challenge.
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Affiliation(s)
- J Vlacic
- School of Dentistry, The University of Queensland, Brisbane.
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Vlacic J, Meyers IA, Kim J, Walsh LJ. Laser-activated fluoride treatment of enamel against an artificial caries challenge: comparison of five wavelengths. Aust Dent J 2007; 52:101-5. [PMID: 17687954 DOI: 10.1111/j.1834-7819.2007.tb00472.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Laser-activated fluoride (LAF) therapy with 488 nm laser energy has been shown previously to increase the resistance of human enamel and dentine to acid dissolution in laboratory models of dental caries. The aims of this study were to examine whether LAF therapy, conducted using a range of wavelengths in the visible and near infrared regions, can protect human dental enamel from an artificial cariogenic challenge. MATERIALS AND METHODS Buccal and lingual surfaces of extracted sound, molar and premolar teeth were used to prepare matched pairs of enamel slabs (N=10 per group). After application of neutral sodium fluoride gel (12300 ppm F ion), slab surfaces were lased (energy density 15 J/cm2; spot size 5mm, wavelength 532, 633, 670, 830 or 1064nm), then exposed to an artificial cariogenic challenge for a period of seven days. The Vicker's hardness number (VHN) was recorded before and after laser treatment and again following the cariogenic challenge. Negative controls did not receive laser exposure. RESULTS All wavelengths of laser light examined provided an effective LAF effect, compared with the unlased negative control surfaces. CONCLUSION Using this in vitro model, we conclude that the action spectrum of the LAF effect extends across the visible and near-infrared regions of the spectrum.
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Affiliation(s)
- J Vlacic
- School of Dentistry, The University of Queensland, Brisbane
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Abstract
Although the individual cariostatic effects of laser and fluoride have been shown, the combined effect of CO(2) laser and fluoride on root demineralization remains uncertain and was the main aim of this study. By using a pH-cycling system and Polarized Light Microscopy, we demonstrated the synergistic effect of fluoride combined with CO(2) laser treatment on reducing root demineralization. The mean lesion depths (in microm) for each group were 160 +/- 14 (Control), 113 +/- 8 (Laser treatment alone), 111 +/- 6 (Fluoride treatment alone), and 25 +/- 7 (Fluoride followed by laser treatment). A significant laser-enhanced fluoride uptake, characterized by the ToF-SIMS analysis, was revealed by the 37% and 400% increments in loosely and firmly bound fluorides (both p < 0.002) in laser-irradiated areas, compared with the non-irradiated controls. In conclusion, there is a significant synergistic effect of combined CO(2) laser and fluoride treatment on the inhibition of root demineralization, possibly due to laser-enhanced fluoride uptake in the root.
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Affiliation(s)
- X-L Gao
- Department of Preventive Dentistry, Faculty of Dentistry, National University of Singapore, 5 Lower Kent Ridge Road, Republic of Singapore 119074
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Steiner-Oliveira C, Rodrigues LKA, Soares LES, Martin AA, Zezell DM, Nobre-dos-Santos M. Chemical, Morphological and Thermal Effects of 10.6-.MU.m CO2 Laser on the Inhibition of Enamel Demineralization. Dent Mater J 2006; 25:455-62. [PMID: 17076314 DOI: 10.4012/dmj.25.455] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Studies have shown that enamel can be modified by pulsed CO2 laser to form a more acid-resistant substrate. This study evaluated the effects of a 10.6-microm CO2 laser on enamel surface morphology and chemical composition as well as monitored intrapulpal temperature changes during irradiation. Human teeth were irradiated with fluences of 1.5-11.5 J/cm2, and pulpal thermal as well as chemical and morphological modifications on enamel were assessed. The teeth were submitted to a pH-cycling model, and the mineral loss was determined by means of cross-sectional microhardness. For all irradiated groups, intrapulpal temperature changes were below 3 degrees C. FT-Raman spectroscopy and scanning electron microscopy indicated that fluences as low as 6.0 J/cm2 were sufficient to induce chemical and morphological changes in enamel. Then, for fluences reaching or exceeding 10.0 J/cm2, laser-induced inhibitory effects on demineralization were observed. It was thus concluded that laser energy density in the range of 10.0 and 11.5 J/cm2 could be applied to dental enamel in order to produce chemical and morphological changes and reduce the acid reactivity of enamel without compromising the pulp vitality.
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Affiliation(s)
- Carolina Steiner-Oliveira
- Department of Pediatric Dentistry, Faculty of Dentistry of Piracicaba, State University of Campinas, São Paulo, Brazil
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Rodrigues LKA, Nobre dos Santos M, Pereira D, Assaf AV, Pardi V. Carbon dioxide laser in dental caries prevention. J Dent 2004; 32:531-40. [PMID: 15304298 DOI: 10.1016/j.jdent.2004.04.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2003] [Revised: 03/25/2004] [Accepted: 04/06/2004] [Indexed: 10/26/2022] Open
Abstract
OBJECTIVES To describe CO2 laser characteristics and to review the literature regarding its effects on caries inhibition in enamel and dentin. Another aim of this review is to discuss the effects of CO2 laser in combination with fluoride. DATA AND SOURCES The literature was searched for review and original research papers relating CO2 laser characteristics, CO2 laser effects on enamel and dentin, use of CO2 laser in dental caries prevention and the effects of CO2 laser in combination with fluoride. The articles have been selected using Medline and manual tracing of references cited in key papers otherwise not elicited. STUDY SELECTION Dental studies pertinent to key aspects of review, and those that focus on CO2 laser. CONCLUSIONS Irradiation of dental enamel by specific wavelengths and fluencies of CO2 laser alters the hydroxyapatite crystals reducing the acid reactivity of the mineral; CO2 laser irradiation in combination with fluoride treatment is more effective in inhibiting caries-like lesions than CO2 laser irradiation or fluoride alone; When laser and fluoride are combined, it is possible to reduce laser energy density and fluoride levels; If this laser technology becomes available at a reasonable cost and the results can be applied in clinical practice, there will be a promising future for this laser in caries prevention.
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Westerman GH, Flaitz CM, Powell GL, Hicks MJ. Enamel caries initiation and progression after argon laser irradiation: in vitro argon laser systems comparison. JOURNAL OF CLINICAL LASER MEDICINE & SURGERY 2002; 20:257-62. [PMID: 12470455 DOI: 10.1089/10445470260420768] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE The purpose of this in vitro laboratory study was to determine the effect of low-fluence argon laser (AL) irradiation delivered from two different argon laser systems on enamel caries-like lesion initiation and progression. BACKGROUND DATA Previous in vitro investigations and a recent in vivo pilot study have shown that AL irradiation of enamel provided a protective effect against in vitro and in vivo cariogenic challenges. MATERIALS AND METHODS Twenty extracted human molars were selected, and 10 teeth were assigned to the HGM argon laser group and 10 were assigned to the LaserMed argon laser group. The exposed buccal windows of sound enamel were exposed to low-fluence irradiation, while the lingual windows of enamel were not exposed to laser irradiation and served as the no-treatment (control) group. Enamel caries-like lesions were created using an acidified gel. Two longitudinal sections were taken per sample (n = 20 lesions per group) and evaluated by polarized light microscopy for body of the lesion depths after lesion initiation (8 weeks) and progression (12 weeks) periods. RESULTS After lesion initiation and progression, the body of lesion depths were similar for both argon-irradiated groups (p > 0.05). With the no-treatment (control) group, there were significant increases in lesion depth with a 61-78% increase for the lesion initiation period and a 50-69% increase for the lesion progression period when compared with the argon laser-treated groups. CONCLUSION Argon laser irradiation provides a certain degree of protection against in vitro enamel caries initiation and progression. Resistance to a continuous caries challenge was similar with either argon laser delivery systems (HGM and LaserMed). Argon laser irradiation may prove to be beneficial in reducing the caries susceptibility of sound enamel and white spot lesions in the clinical environment.
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Affiliation(s)
- Gary H Westerman
- Department of Community and Preventive Dentistry, Creighton University, School of Dentistry, Omaha, Nebraska, USA.
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Abstract
This article summarizes the effectiveness of restorative materials used to restore root surfaces, the mechanisms by which these materials reduce caries, and placement techniques for restoring root-surface lesions. Patients may be classified into low, medium, and high caries risk groups for root caries, and specific dental restorative material recommendations are made for each category. Effective plaque control, xylitol-containing chewing gums, antimicrobial agents, fluoride-releasing restorative materials, topically applied fluoride, and fluoride-containing toothpastes provide maximum protection for the high caries risk patient.
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Affiliation(s)
- John O Burgess
- Operative Dentistry and Biomaterials, 1100 Florida Avenue, New Orleans, LA 70179, USA.
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Hossain MMI, Hossain M, Kimura Y, Kinoshita JI, Yamada Y, Matsumoto K. Acquired acid resistance of enamel and dentin by CO2 laser irradiation with sodium fluoride solution. JOURNAL OF CLINICAL LASER MEDICINE & SURGERY 2002; 20:77-82. [PMID: 12017431 DOI: 10.1089/104454702753768052] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The purpose of this study was to investigate the caries-preventive effect of CO2 laser irradiation with or without sodium fluoride (NaF) solution at human dental enamel and dentin in vitro. BACKGROUND DATA The capability of caries prevention with CO2 laser irradiation has been reported in many previous studies, but few studies have been performed with regard to the combined effect of fluoride and laser. MATERIALS AND METHODS Forty extracted human incisor teeth were used for the enamel study, and 40 molar teeth were used for the dentin study. Samples were then divided into four categories: control (no treatment); CO2 laser irradiation only; NaF treatment only; and NaF treatment followed by CO2 laser irradiation. Each sample was immersed in 2 mL of lactic acid (0.1 M, pH 4.8) solution for 24 h at 37 degrees C in 100% humidity. The parts per million (ppm) of calcium ion (Ca2+) dissolved in each solution was determined by atomic absorption spectrophotometry. The samples were also observed by stereoscopy and scanning electron microscopy (SEM). RESULTS The lowest mean Ca2+ ppm was recorded at the enamel or dentin samples treated with NaF and laser. Statistical analysis of the data was considered significant (p < 0.01). SEM observation showed that surfaces were changed to melted, smooth, and mirror-like appearances when CO2 laser irradiation was applied with NaF solution. CONCLUSION It can be concluded that CO2 laser irradiation with NaF solution has more caries-preventive effect than CO2 laser irradiation only at the enamel and dentin surfaces.
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Affiliation(s)
- M M Iqbal Hossain
- Department of Endodontics, Showa University School of Dentistry, Tokyo, Japan
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17
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Matsumoto K, Hossain M, Hossain MMI, Kawano H, Kimura Y. Clinical assessment of Er,Cr:YSGG laser application for cavity preparation. JOURNAL OF CLINICAL LASER MEDICINE & SURGERY 2002; 20:17-21. [PMID: 11905432 DOI: 10.1089/104454702753474968] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In this study, an erbium,chromium:YSGG (Er,Cr:YSGG) laser emitting at a wavelength of 2.78 microm was clinically applied to remove caries and prepare cavities, and the clinical outcome was evaluated. Effective clinical application of Er,Cr:YSGG laser had been expected from previous studies. This study included 44 patients (26 females, 18 males; aged 23-58) with a total of 50 cavity preparations by the Er,Cr:YSGG laser irradiation at 3-6 W with water spray. Patient acceptance and prognosis were evaluated. Most cases (94%) were prepared without anesthesia, and no pain was felt in 34 cases (68%). No adverse reaction was observed in any of the cases, and patient acceptance for this system was favorable. All cases had a good prognosis. In 45 cases (90%), overall clinical evaluation was satisfactory. From the present study, it can be concluded that the Er,Cr:YSGG laser system is an efficient, effective, and safe device for caries removal and cavity preparation.
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Affiliation(s)
- Koukichi Matsumoto
- Department of Endodontics, Showa University School of Dentistry, Tokyo, Japan.
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18
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Yamada Y, Hossain M, Nakamura Y, Suzuki N, Matsumoto K. Comparison between the removal effect of mechanical, Nd:YAG, and Er:YAG laser systems in carious dentin. JOURNAL OF CLINICAL LASER MEDICINE & SURGERY 2001; 19:239-43. [PMID: 11710618 DOI: 10.1089/10445470152611964] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The purpose of this study was to compare the effectiveness of carious dentin removal by using an Er:YAG laser irradiation and Nd:YAG laser under a continuous water spray with that of the conventional mechanical treatment in vitro. BACKGROUND DATA Lasers are being considered as a potential replacement of conventional mechanical systems to remove diseased and healthy dental hard tissues. METHODS First, one half of the 10 carious lesions were treated with the round steel bur and then removed. The other half were treated with the Er:YAG laser at 200-mJ pulse energy at 2 Hz. After that, one half of another set of 10 teeth was subjected to the round steel bur in which the other half was removed using the Nd:YAG laser at 6-W output power, 20 pps, and under a continuous water spray (120 mL/min). Thermal change during each treatment and the time required for carious dentin removal was determined, and the surface characteristic was observed using the scanning electron microscopic (SEM). RESULTS The Er:YAG or Nd:YAG laser irradiation time was almost two or three times longer than the bur treatment, respectively. From the SEM study, it was found that the lased cavity surface revealed various patterns of microirregularity, and there was also no smear layer. CONCLUSIONS It can be suggested that under adequate water spray and with a careful irradiation technique, cavities without sign of thermal damage to the surrounding tissues as well as dental pulp could be produced with the Er:YAG and Nd:YAG laser.
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Affiliation(s)
- Y Yamada
- Department of Endodontics, Showa University School of Dentistry, Tokyo, Japan
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19
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Hossain M, Kimura Y, Nakamura Y, Yamada Y, Kinoshita JI, Matsumoto K. A study on acquired acid resistance of enamel and dentin irradiated by Er,Cr:YSGG laser. JOURNAL OF CLINICAL LASER MEDICINE & SURGERY 2001; 19:159-63. [PMID: 11469308 DOI: 10.1089/10445470152927991] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE This investigation was performed to evaluate the acid resistance of lased enamel and dentin by Er,Cr:YSGG laser to artificial caries-like lesions by spectrophotometry, and the ultrastructure of lased areas was investigated by scanning electron microscopy (SEM) in vitro. BACKGROUND DATA In recent years, many studies have been performed to evaluate the effects of Er,Cr:YSGG laser on dental hard tissues. However, there have been only a few studies to determine if this laser is suitable for caries preventive treatments. METHODS An Er,Cr:YSGG laser was used to irradiate the enamel or dentin samples from 30 extracted human molars at 6 W (67.9 J/cm2) or 5 W (56.6 J/cm2) pulse energy, respectively, with or without water mist. Samples were subjected to 2 microl of 0.1 M lactic acid solution (pH 4.8) for 24 h at 36 degrees C. The parts per million (ppm) of calcium ion (Ca2+) dissolved in each solution was determined by atomic absorption spectrophotometery, and the morphological changes were investigated by SEM. RESULTS The lowest mean Ca2+ ppm was recorded in the lased samples. SEM observation showed that the lased areas were melted and seemed to be thermally degenerated. After acid demineralization, the thermally degenerated enamel or dentin surfaces were almost unchanged. CONCLUSIONS The results of this study suggested that Er,Cr:YSGG laser irradiation with and without water mist appears to be effective for increasing acid resistance.
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Affiliation(s)
- M Hossain
- Department of Endodontics, Showa University School of Dentistry, Tokyo, Japan
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20
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Yamada Y, Hossain M, Suzuki N, Kinoshita JI, Nakamura Y, Matsumoto K. Removal of carious dentin by Er:YAG laser irradiation with and without carisolv. JOURNAL OF CLINICAL LASER MEDICINE & SURGERY 2001; 19:127-31. [PMID: 11469304 DOI: 10.1089/10445470152927955] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE The purpose of this study was to investigate the effectiveness of caries removal by using an Er:YAG laser irradiation with and without Carisolv, in vitro. BACKGROUND DATA Effective ablation of dental hard tissues using Er:YAG laser has been reported and its application to caries removal has been expected. METHODS Five extracted human teeth were selected for Carisolv and burr treatment. One-half of the lesion was treated with the Carisolv and then removed. The other half was removed using burr treatment. Fifty teeth were subjected to Er:YAG laser treatment with and without Carisolv. First, Carisolv was applied on one-half of each carious lesions for 1 min and followed by the Er:YAG laser irradiation at 60-140 mJ, 2 Hz for another 1 min; the other half was treated with Er:YAG laser only. The cavity was carefully assessed by DIAGNOdent. Each lesion was photographed before and after treatment, and the treated cavity was observed by microscopy and with scanning electron microscope (SEM). RESULTS Our results revealed that application of Carisolv followed by Er:YAG laser irradiation at 100-140 mJ pulse energy effectively removed dentin caries. From the SEM study, it was found that the cavity surface treated with the laser revealed various patterns of microirregularity, often accompanied by microfissure propagation. There was also no smear layer. CONCLUSIONS It was revealed that Er:YAG laser and Carisolv could provide an alternative technique for caries removal for conventional mechanical drilling and cutting.
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Affiliation(s)
- Y Yamada
- Department of Endodontics, Showa University School of Dentistry, Tokyo, Japan
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21
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Hossain M, Nakamura Y, Kimura Y, Yamada Y, Kawanaka T, Matsumoto K. Effect of pulsed Nd:YAG laser irradiation on acid demineralization of enamel and dentin. JOURNAL OF CLINICAL LASER MEDICINE & SURGERY 2001; 19:105-8. [PMID: 11443789 DOI: 10.1089/104454701750285421] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE The purpose of this study was to investigate the effect of Nd:YAG laser irradiation on the acid demineralization of enamel and dentin by spectrophotometry. A mechanism of acquired acid resistance is also proposed. SUMMARY BACKGROUND DATA The ability of Nd:YAG laser irradiation to the enhanced resistance to artificial caries formation is still controversial. METHODS A pulsed Nd:YAG laser at 1.064-micron wavelength was used to irradiate the human enamel and dentin samples from 20 extracted human molars at the parameters of 1, 2, and 3 W and 20 pps for a total of 9 sec after painting with black ink. Samples were then subjected to 2 microliters of 0.1 M lactic acid solution (pH 4.8) for 24 h at 36 degrees C. The parts per million (ppm) of calcium ion (Ca2+) dissolved in each solution was determined by atomic absorption spectrophotometry and the morphological changes were also investigated by scanning electron microscopy (SEM). RESULTS The lowest mean Ca2+ ppm was recorded in the samples irradiated at 3 W, in those by irradiated at 2 W and 1 W. The unlased samples showed the highest Ca2+ ppm. SEM observation showed that in the lased areas, the smear layer was partially melted and the underlying primary enamel or dentin seemed to be thermally degenerated. CONCLUSIONS The results of this study suggested that melted smear layer and underlying enamel or dentin degenerated thermally by the heat treatment of Nd:YAG laser might play a major role to enhance resistance to artificial caries-like formation.
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Affiliation(s)
- M Hossain
- Department of Endodontics, Showa University School of Dentistry, Tokyo, Japan
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22
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Yamada Y, Hossain M, Kawanaka T, Kinoshita J, Matsumoto K. Removal effects of the Nd:YAG laser and Carisolv on carious dentin. JOURNAL OF CLINICAL LASER MEDICINE & SURGERY 2000; 18:241-5. [PMID: 11572238 DOI: 10.1089/clm.2000.18.241] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
OBJECTIVE The purpose of this study was to investigate the removal effect of the Nd:YAG laser irradiation and Carisolv on carious dentin. BACKGROUND DATA Many previous studies have reported several simple and alternative techniques, such as lasers and chemicals, for caries removal. METHODS Carisolv was applied on the surface of 20 extracted human anterior and molar teeth for 1 min and then the Nd:YAG laser was irradiated with a continuous water spray for another 1 min. The energy densities were varied from 2 to 6W with a repetition rate of 20 pps. As caries removal progressed, the cavity was carefully assessed by DIAGNOdent. Each lesion was photographed before and after treatment, and the treated cavity was observed microscopically using a stereoscope and with scanning electron microscope (SEM). Thermal change at the time of laser irradiation was measured by thermovision. RESULTS Our results revealed that application of Carisolv followed by Nd:YAG laser irradiation at 4-6W pulse energy effectively removed dentin caries. The total procedure was usually repeated once or twice for complete caries removal. From the SEM study, it was found that the cavity surface treated with the laser revealed various patterns of microirregularity, often accompanied by microfissure propagation. There was also no smear layer. CONCLUSIONS It was revealed that Nd:YAG laser and Carisolv could provide an alternative technique for caries removal instead of the conventional mechanical drilling and cutting.
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Affiliation(s)
- Y Yamada
- Department of Endodontics, Showa University School of Dentistry, Tokyo, Japan
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23
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Hossain M, Nakamura Y, Kimura Y, Yamada Y, Ito M, Matsumoto K. Caries-preventive effect of Er:YAG laser irradiation with or without water mist. JOURNAL OF CLINICAL LASER MEDICINE & SURGERY 2000; 18:61-5. [PMID: 11800104 DOI: 10.1089/clm.2000.18.61] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE This investigation was performed to evaluate the effect of Er:YAG laser irradiation on the acquired acid resistance of sound dental hard tissues to artificial caries formation by spectrophotometry, and the ultrastructure of lased areas was investigated by scanning electron microscopy (SEM) in vitro. BACKGROUND DATA Although an Er:YAG laser has shown the most promise for hard tissue ablation, there have not been any dissolution studies to determine if this laser is suitable for caries preventive treatments. METHODS An Er:YAG laser was used to irradiate the enamel and dentin samples from 20 extracted human molars at 400 mJ pulse energy with or without water mist. Samples were subjected to 2 microL of 0.1 M lactic acid solution (pH 4.8) for 24 hours at 36 degrees C. The parts per million (ppm) of calcium ion (Ca2+) dissolved in each solution was determined by atomic absorption spectrophotometry and the morphological changes were investigated by SEM. RESULTS The lowest mean Ca2+ ppm was recorded in the samples irradiated without water mist, in those by irradiated with water mist, and in the unlased samples. SEM observation showed that the lased areas had melted and seemed to be thermally degenerated when irradiated without water mist. After acid demineralization, the thermally degenerated enamel or dentin surfaces were almost unchanged. CONCLUSIONS The results of this study suggest that Er:YAG laser irradition with and without water mist appears to be more effective for caries prevention.
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Affiliation(s)
- M Hossain
- Department of Endodontics, Showa University School of Dentistry, Tokyo, Japan
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Blankenau RJ, Powell G, Ellis RW, Westerman GH. In vivo caries-like lesion prevention with argon laser: pilot study. JOURNAL OF CLINICAL LASER MEDICINE & SURGERY 1999; 17:241-3. [PMID: 11800094 DOI: 10.1089/clm.1999.17.241] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE This clinical pilot study was conducted to investigate the effectiveness of argon laser irradiation to reduce demineralization or loss of tooth structure in vivo. SUMMARY BACKGROUND DATA In vitro research previously demonstrated the ability of argon laser irradiation to reduce demineralization or loss of tooth structure. METHODS Using the Ogaard model of producing demineralization, the experimental teeth were irradiated with argon laser of 250 mW (producing approximately 12 J/cm2) prior to banding. Polarized light evaluation of the sectioned, extracted teeth was used to determine the amount of demineralization. RESULTS Results showed a 29.1% reduction in demineralization in the experimental teeth as compared to the bilateral control teeth. CONCLUSION Low-power argon laser irradiation significantly reduced demineralization clinically.
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25
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Lin S, Caputo AA, Eversole LR, Rizoiu I. Topographical characteristics and shear bond strength of tooth surfaces cut with a laser-powered hydrokinetic system. J Prosthet Dent 1999; 82:451-5. [PMID: 10512965 DOI: 10.1016/s0022-3913(99)70033-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
STATEMENT OF PROBLEM Erbium lasers, specifically Er;YAG and Er, Cr;YSGG that emit in the near red wavelengths, cut both enamel and dentine. Bonding to these cut surfaces with composites has not been assessed for all laser systems. PURPOSE This investigation assessed the shear bond strength of composite bonded to tooth structure treated with an Er,Cr;YSGG-powered hydrokinetic system (HKS, Millennium system) and then was compared with surfaces treated with a carbide bur. MATERIAL AND METHODS Extracted human molars were cut into enamel and dentin with both systems. Nonetched and acid-etched subgroups were evaluated. Shear bond strength was measured with an Instron test machine with a knife-edge loading head. In addition, SEMs were evaluated. RESULTS There were no significant differences in shear bond strength between etched bur cut (23.3 +/- 2.5 MPa), etched laser-cut enamel (23.7 +/- 4.5 MPa), and nonetched laser-cut enamel (20.5 +/- 2.8 MPa). For nonetched enamel, bond strength values for laser-cut surfaces were significantly higher than the bur-cut surfaces (8.7 +/- 4.3 MPa). Bond strength differences for dentin between bur (14.3 +/- 1.7 MPa) and laser cuts (11.5 +/- 4.3 MPa) were not significant (P =.03). SEM revealed that laser cutting of enamel did not cause formation of a smear layer. CONCLUSION There were no significant differences in shear bond strength between etched bur-cut, etched laser-cut, and nonetched laser-cut enamel. With nonetched enamel, bond strength values for nonetched laser-cut surfaces were significantly higher than for the bur-cut surfaces. No bond strength differences between bur and laser cutting existed for dentin. Similar topography was observed for bur and laser prepared surfaces of etched enamel and nonetched dentin.
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Affiliation(s)
- S Lin
- Department of Biomaterials Science, University of the Pacific School of Dentistry, San Francisco, CA 94115, USA
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26
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Hossain M, Nakamura Y, Kimura Y, Ito M, Yamada Y, Matsumoto K. Acquired acid resistance of dental hard tissues by CO2 laser irradiation. JOURNAL OF CLINICAL LASER MEDICINE & SURGERY 1999; 17:223-6. [PMID: 11199827 DOI: 10.1089/clm.1999.17.223] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE This investigation was performed to evaluate the effect of CO2 laser irradiation on the acquired acid resistance of dental hard tissues to artificial caries-like formation and the ultrastructure of lased areas was morphologically investigated in vitro. SUMMARY BACKGROUND DATA In recent years, many studies have been carried out to evaluate the effect of the CO2 laser on the enhanced resistance to artificial caries formation of enamel. However, a limited number of papers concerning its effect on dentin have been published. METHODS A CO2 laser of 10.6 microns wavelength was used to irradiate human enamel and dentin samples from 20 extracted human molar teeth, and samples were subjected to 2 microliters of 0.1 M lactic acid solution (pH 4.8) for 24 h at 36 degrees C. The parts per million (ppm) of calcium ion (Ca2+) dissolved in each solution was determined by atomic absorption spectrophotometry and the morphological changes were investigated by scanning electron microscopy (SEM). RESULTS The lowest mean Ca2+ ppm was recorded in the samples irradiated at 3 W, followed by 2 W, 1 W, and unlased samples. SEM observation showed that the lased areas were melting with solidification of the smear layer. Even after acid demineralization, the lased surfaces were almost unchanged. CONCLUSIONS The results of this study suggested that CO2 laser irradiation could sufficiently melt and solidify the enamel and dentin surfaces and thus enhance resistance to artificial caries-like formation.
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Affiliation(s)
- M Hossain
- Department of Endodontics, Showa University School of Dentistry, Tokyo, Japan
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27
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Westerman GH, Hicks MJ, Flaitz CM, Blankenau RJ, Powell GL. Combined effects of acidulated phosphate fluoride and argon laser on sound root surface morphology: an in vitro scanning electron microscopy study. JOURNAL OF CLINICAL LASER MEDICINE & SURGERY 1999; 17:63-8. [PMID: 11189977 DOI: 10.1089/clm.1999.17.63] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE The purpose of this in vitro scanning electron microscopy (SEM) study was to evaluate the effects of combining low fluence argon laser (AL) irradiation and acidulated phosphate fluoride (APF) treatment on the surface morphology of sound human root surfaces. SUMMARY BACKGROUND DATA Previous in vitro investigations have shown that combined APF and AL irradiation of root surfaces provided a protective effect against cariogenic challenges. MATERIALS AND METHODS Twelve extracted human molars were sectioned into quarters, and each quarter assigned to 1 of 4 treatment groups: (1) no treatment/control; (2) low fluence (11.5 J/cm2) AL irradiation; (3) 1.23% APF for 4 minutes; (4) APF treatment followed by low fluence AL irradiation. Surface morphology alterations were compared among groups using SEM techniques. RESULTS AL irradiation alone produced irregular textured surfaces with adherent globular material and fine microporsities in the background. APF treatment, alternatively, only created relatively smooth surface coatings that masked the original underlying root surface. Combining APF treatment followed by AL irradiation resulted in a surface coating composed of relatively small (2 to 3 microns) spherical to avoid precipitates, morphologically resembling calcium fluoride. CONCLUSION Combining APF with AL irradiation may create a more reactive surface that possesses fluoride-rich mineral deposits and protects the underlying root surface from cariogenic challenges.
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Affiliation(s)
- G H Westerman
- Department of Community and Preventive Dentistry, Creighton University, School of Dentistry, Omaha, Nebraska, USA.
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28
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Featherstone JD, Barrett-Vespone NA, Fried D, Kantorowitz Z, Seka W. CO2 laser inhibitor of artificial caries-like lesion progression in dental enamel. J Dent Res 1998; 77:1397-403. [PMID: 9649168 DOI: 10.1177/00220345980770060401] [Citation(s) in RCA: 125] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Several studies during the last 30 years have demonstrated the potential of laser pre-treatment of enamel or tooth roots to inhibit subsequent acid-induced dissolution or artificial caries-like challenge in the laboratory. The overall objective of ongoing studies in our laboratories is to determine, systematically, the optimum sets of parameters for carbon dioxide laser irradiation that will potentially effectively inhibit dental caries in enamel and tooth roots. The aim of the present study was to examine the roles of wavelength and fluence in the prevention of caries progression in vitro in enamel by means of a pH-cycling model. The hypothesis to be tested was that the highly absorbed 9.3- and 9.6-microm wavelengths would be efficiently converted to heat, creating a temperature sufficiently high to reduce the acid-reactivity of the mineral and inhibit caries-like lesion progression in dental enamel. One hundred and sixty caries-free tooth crowns were cleaned and varnished with acid-resistant varnish, leaving one exposed window of enamel. Twelve groups of 10 enamel samples were irradiated in their individual windows by one of the four wavelengths (9.3, 9.6, 10.3, or 10.6 microm) of a tunable CO2 laser. Energy per pulse was 25, 50, 100, 200, or 250 mJ (25 pulses). Repetition rate was 10 Hz, and beam diameter was 1.6 mm. Fluence conditions of 1 to 12.5 J/cm2 per pulse were produced. All teeth, including 40 non-irradiated controls, were subjected to pH-cycling to produce artificial caries-like lesions. Results were assessed by cross-sectional microhardness testing. Inhibition of caries progression of from 40% to 85% was achieved over the range of laser conditions tested. At 9.3 and 9.6 microm, 25 pulses at absorbed fluences of 1 to 3 J/cm2 produced inhibition on the order of 70% with minimal subsurface temperature elevation (< 1 degree C at 2 mm depth), comparable with inhibition produced in this model with daily fluoride dentifrice treatments. Safety and efficacy studies will be required in animals and humans before these promising laboratory results can be applied in clinical practice.
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Affiliation(s)
- J D Featherstone
- Department of Restorative Dentistry, University of California at San Francisco, 94143-0758, USA
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29
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Anić I, Tachibana H, Masumoto K, Qi P. Permeability, morphologic and temperature changes of canal dentine walls induced by Nd: YAG, CO2 and argon lasers. Int Endod J 1996; 29:13-22. [PMID: 9206407 DOI: 10.1111/j.1365-2591.1996.tb01354.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The permeability, temperature and morphologic changes of the wall of the root canal induced by Nd:YAG, CO2 and argon lasers were studied. The changes were evaluated according to the presence or absence of a smear layer. Root canals of 140 human single-rooted teeth were enlarged using a step-back technique. Permeability was evaluated by the extent of methylene blue dye penetration into the tubules. Temperature changes were measured using a thermovision system, and morphological changes were evaluated by scanning electron microscopy. Laser energy was delivered into the canal by means of a flexible optical fibre or metal tip. There were statistically significant differences in permeability between lased groups with and without a smear layer in the cervical third of the root canal following lasing. In the middle third of the root canal, all three laser types induced permeability increases in groups with a smear layer. In the apical third, statistically significantly decreases in permeability were observed among CO2 laser and Nd:YAG compared with control group (P < 0.01). Rises in temperature ranged from a minimum of +10.1 degrees C (CO2 laser) to a maximum of +54.8 degrees C (argon laser). All three laser devices appeared capable of producing a glazed-like surface and craters.
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Affiliation(s)
- I Anić
- Department of Dental Pathology, School of Dentistry, University of Zagreb, Croatia
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