Effect of Nd:YAG and CO2 Laser Irradiation on Prevention of Enamel Demineralization in Orthodontics: In Vitro Study

The aim of this in vitro study was to evaluate the effect of combined CO2 laser and tin-containing fluoride treatment on the formation and progression of enamel erosive lesions. Ninety-six human enamel samples were obtained, stored in thymol solution and, after surface polishing, randomly divided into 6 different surface treatment groups (n = 16 in each group) as follows: no treatment, control (C); one CO2 laser irradiation (L1); two CO2 laser irradiations (L2); daily application of fluoride solution (F); combined daily fluoride solution + one CO2 laser irradiation (L1F), and combined daily fluoride solution + two CO2 laser irradiations (L2F). Laser irradiation was performed at 0.3 J/cm2 (5 µs/226 Hz/10.6 µm) on day 1 (L1) and day 6 (L2). The fluoride solution contained AmF/NaF (500 ppm F), and SnCl2 (800 ppm Sn) at pH 4.5. After surface treatment the samples were submitted to an erosive cycling over 10 days, including immersion in citric acid (2 min/0.05 M/pH = 2.3) 6 times daily and storage in remineralization solution (≥1 h) between erosive attacks. At the end of each cycling day, the enamel surface loss (micrometers) was measured using a 3D laser profilometer. Data were statistically analyzed by means of a 2-level mixed effects model and linear contrasts (α = 0.05). Group F (-3.3 ± 2.0 µm) showed significantly lower enamel surface loss than groups C (-27.22 ± 4.1 µm), L1 (-18.3 ± 4.4 µm) and L2 (-16.3 ± 5.3 µm) but higher than L1F (-1.0 ± 4.4 µm) and L2F (1.4 ± 3.2 µm, p < 0.05). Under the conditions of this in vitro study, the tin-containing fluoride solution caused 88% reduction of enamel surface loss, while its combination with CO2 laser irradiation at 0.3 J/cm2 hampered erosive loss almost completely.

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Effects of CO2 laser irradiation on matrix-rich biofilm development formation – An in vitro study

10.7287/peerj.preprints.2084 ◽

2016 ◽

Author(s):

Bruna Raquel Zancope ◽

Vanessa B Dainezi ◽

Marinês Nobre-dos-Santos ◽

Sillas Duarte, Jr ◽

Vanessa Pardi ◽

...

Keyword(s):

Contact Angle ◽

Laser Irradiation ◽

Co2 Laser ◽

Biofilm Formation ◽

In Vitro Study ◽

Vitro Study ◽

Enamel Surface ◽

Control Group ◽

Biofilm Development

Background. CO2 laser has been used to morphologically and chemically modify the dental enamel surface as well as to turn it more resistant to demineralization. Despite a variety of experiments demonstrating the inhibitory effect of CO2 laser in reduce enamel demineralization, little is known about the effect of surface irradiated on bacterial growth. Thus, this in vitro study was preformed to evaluate the biofilm formation on enamel previously irradiated with a CO2 laser (λ = 10.6 µM). Methods. For this in vitro study, it was employed 96 specimens of bovine enamel, which were divided into 2 groups (n = 48): 1) Control-non-irradiated surface and 2) Irradiated enamel surface. Biofilms were grown on the enamel specimens by 1, 3 and 5 days under intermittent cariogenic condition in the irradiated and non irradiated surface. In each assessment time, the biofilm were evaluated by dry weigh, counting the number of viable colonies and in fifth day, were evaluated by polysaccharides analysis, quantitative real time PCR as well as by contact angle. In addition, the morphology of biofilms was characterized by fluorescence microscopy and field emission scanning electron microscopy (FESEM). Initially, the assumptions of equal variances and normal distribution of errors were conferred and the results are analyzed statistically by t-test and Mann Whitney test. Results. The mean of log CFU/ml obtained for the 1-day biofilm evaluation showed that there is statistical difference between the experimental groups. When biofilms were exposed to CO2 laser, CFU/mL and CFU/ Dry Weight in 3 day was reduced significantly compared with control group. The difference in the genes expression (gtfB and gbpB) and polysaccharides was not statically significant. Contact angle was increased relative to control when the surface was irradiated with CO2 laser. Similar morphology was also visible with both treatments, however irradiated group revealed evidence of melting and fusion in the specimens. Conclusion. In conclusion CO2 laser irradiation modify the energy surface and disrupt the initial biofilm formation.

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Effects of CO2 Laser Irradiation on Treatment of Hypersensitive Dental Necks: Results of an in Vitro Study

Journal of Clinical Laser Medicine & Surgery ◽

10.1089/clm.1995.13.397 ◽

1995 ◽

Vol 13 (6) ◽

pp. 397-400 ◽

Cited By ~ 8

Author(s):

A. MORITZ ◽

N. GUTKNECHT ◽

U. SCHOOP ◽

J. WERNISCH ◽

F. LAMPERT ◽

...

Keyword(s):

Laser Irradiation ◽

Co2 Laser ◽

In Vitro Study ◽

Vitro Study

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CO2 laser irradiation enhances CaF2 formation and inhibits lesion progression on demineralized dental enamel—in vitro study

Lasers in Medical Science ◽

10.1007/s10103-016-1900-4 ◽

2016 ◽

Vol 31 (3) ◽

pp. 539-547 ◽

Cited By ~ 10

Author(s):

Bruna R. Zancopé ◽

Lívia P. Rodrigues ◽

Thais M. Parisotto ◽

Carolina Steiner-Oliveira ◽

Lidiany K. A. Rodrigues ◽

...

Keyword(s):

Laser Irradiation ◽

Co2 Laser ◽

Dental Enamel ◽

In Vitro Study ◽

Vitro Study

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Effects of CO2 laser irradiation on matrix-rich biofilm development formation – An in vitro study

10.7287/peerj.preprints.2084v1 ◽

2016 ◽

Author(s):

Bruna Raquel Zancope ◽

Vanessa B Dainezi ◽

Marinês Nobre-dos-Santos ◽

Sillas Duarte, Jr ◽

Vanessa Pardi ◽

...

Keyword(s):

Contact Angle ◽

Laser Irradiation ◽

Co2 Laser ◽

Biofilm Formation ◽

In Vitro Study ◽

Vitro Study ◽

Enamel Surface ◽

Control Group ◽

Biofilm Development

Background. CO2 laser has been used to morphologically and chemically modify the dental enamel surface as well as to turn it more resistant to demineralization. Despite a variety of experiments demonstrating the inhibitory effect of CO2 laser in reduce enamel demineralization, little is known about the effect of surface irradiated on bacterial growth. Thus, this in vitro study was preformed to evaluate the biofilm formation on enamel previously irradiated with a CO2 laser (λ = 10.6 µM). Methods. For this in vitro study, it was employed 96 specimens of bovine enamel, which were divided into 2 groups (n = 48): 1) Control-non-irradiated surface and 2) Irradiated enamel surface. Biofilms were grown on the enamel specimens by 1, 3 and 5 days under intermittent cariogenic condition in the irradiated and non irradiated surface. In each assessment time, the biofilm were evaluated by dry weigh, counting the number of viable colonies and in fifth day, were evaluated by polysaccharides analysis, quantitative real time PCR as well as by contact angle. In addition, the morphology of biofilms was characterized by fluorescence microscopy and field emission scanning electron microscopy (FESEM). Initially, the assumptions of equal variances and normal distribution of errors were conferred and the results are analyzed statistically by t-test and Mann Whitney test. Results. The mean of log CFU/ml obtained for the 1-day biofilm evaluation showed that there is statistical difference between the experimental groups. When biofilms were exposed to CO2 laser, CFU/mL and CFU/ Dry Weight in 3 day was reduced significantly compared with control group. The difference in the genes expression (gtfB and gbpB) and polysaccharides was not statically significant. Contact angle was increased relative to control when the surface was irradiated with CO2 laser. Similar morphology was also visible with both treatments, however irradiated group revealed evidence of melting and fusion in the specimens. Conclusion. In conclusion CO2 laser irradiation modify the energy surface and disrupt the initial biofilm formation.

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Intrapulpar temperature during continuous CO2 laser irradiation in human molars: An in vitro study

Journal of Laser Applications ◽

10.2351/1.4745472 ◽

1997 ◽

Vol 9 (6) ◽

pp. 291-294 ◽

Cited By ~ 5

Author(s):

Walter Niccoli‐Filho ◽

José Camilo Furlani ◽

Carlos Schwab ◽

Fernando Vagner Raldi ◽

Carlos de Paula Eduardo

Keyword(s):

Laser Irradiation ◽

Co2 Laser ◽

In Vitro Study ◽

Vitro Study ◽

Continuous Co2 Laser

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Prevention of enamel demineralization during orthodontic treatment: An in vitro study using pit and fissure sealants

American Journal of Orthodontics and Dentofacial Orthopedics ◽

10.1016/s0889-5406(96)70050-1 ◽

1996 ◽

Vol 110 (5) ◽

pp. 459-465 ◽

Cited By ~ 34

Author(s):

Michael C. Frazier ◽

Thomas E. Southard ◽

Philip M. Doster

Keyword(s):

Orthodontic Treatment ◽

In Vitro Study ◽

Vitro Study ◽

Fissure Sealants ◽

Pit And Fissure Sealants ◽

Enamel Demineralization

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Er:YAG laser-induced damage to a dental composite in simulated clinical scenarios for inadvertent irradiation: an in vitro study

Lasers in Medical Science ◽

10.1007/s10103-021-03348-4 ◽

2021 ◽

Author(s):

Katharina Kuhn ◽

Carmen U. Schmid ◽

Ralph G. Luthardt ◽

Heike Rudolph ◽

Rolf Diebolder

Keyword(s):

Laser Irradiation ◽

Laser Fluence ◽

Ablation Threshold ◽

Er:Yag Laser ◽

In Vitro Study ◽

Vitro Study ◽

Crater Diameter ◽

Clinical Scenarios ◽

Laser Induced Damage

AbstractInadvertent Er:YAG laser irradiation occurs in dentistry and may harm restorative materials in teeth. The aim of this in vitro study was to quantify Er:YAG laser-induced damage to a nanohybrid composite in simulated clinical scenarios for inadvertent direct and indirect (reflection) laser irradiation. The simulation was performed by varying the output energy (OE;direct˃indirect) reaching the specimen and the operating distance (OD;direct˂indirect). Composite specimens were irradiated by an Er:YAG laser. The ablation threshold was determined and clinically relevant parameters were applied (n = 6 for each OE/OD combination) for direct (OE: 570 mJ/OD: 10 mm, OE: 190 mJ/OD: 10 mm) and indirect irradiation (OE: 466 mJ/OD: 15 mm, OE: 57 mJ/OD: 15 mm, OE: 155 mJ/OD: 15 mm, OE: 19 mJ/OD: 15 mm). The extent of damage in the form of craters was evaluated using a laser scanning microscope (LSM) and a conventional light microscope (LM). The ablation threshold was determined to be 2.6 J/cm2. The crater diameter showed the highest value (LM: 1075 ± 18 µm/LSM: 1082 ± 17 µm) for indirect irradiation (reflectant:dental mirror) (OE: 466 mJ/OD: 15 mm). The crater depth showed the highest and comparable value for direct (OE: 570 mJ/OD: 10 mm; LSM: 89 ± 2 µm) and indirect irradiation (OE: 466 mJ/OD: 15 mm; LSM: 90 ± 4 µm). For each OD, the crater diameter, depth, and volume increased with higher laser fluence. However, the OD—and thus the laser spot diameter—also had an enlarging effect. Thus, indirect irradiation (reflectant:dental mirror) with only 47% of the laser fluence of direct irradiation led to a larger diameter and a comparable depth. The three-dimensional extent of the crater was large enough to cause roughening, which may lead to plaque accumulation and encourage caries, gingivitis, and periodontitis under clinical conditions. Clinicians should be aware that reflected irradiation can still create such craters.

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