Atomic analysis and knoop hardness measurement of the cavity floor prepared by Er,Cr:YSGG laser irradiation in vitro

The aims of this in vitro study were both to determine the time necessary for removal of carious dentin (efficiency) and the Knoop Hardness Number (KHN) of the remaining dentin (effectiveness), using a chemomechanical method (Carisolv) or hand excavation. Thirty human molars were bisected through occlusal carious lesions into two equal halves. Each half was randomly excavated by hand in circular movements with a spoon excavator or using Carisolv gel according to the manufacturer's instructions. The duration of carious dentin removal was recorded. Tooth sections were resin-embedded, ground flat and polished. Dentin KHN was determined at distances of 100, 200, 300, 400 and 500 mum from the cavity floor. Data were analyzed by Wilcoxon's test (alpha=0.01), ANOVA and Student's t test (alpha= 0.05). The median of the time necessary for chemomechanical excavation was significantly greater than for hand excavation. KHN means (± SD) at 100, 200, 300, 400, 500 µm for chemomechanical method were, respectively: 15.6 (±4.96), 18.0 (±6.22), 21.3 (±9.30), 24.3 (±9.25), 28.5 (±11.80); and for hand excavation were: 21.2 (±10.26), 23.4 (±9.49), 28.2 (±11.62), 31.0 (±12.17), 34.3 (±11.95). It may be concluded that hand excavation presented higher efficiency and effectiveness than chemomechanical excavation.

Download Full-text

Carbon dioxide laser irradiation of bacterial targets in vitro

Journal of Hospital Infection ◽

10.1016/0195-6701(87)90123-x ◽

1987 ◽

Vol 9 (3) ◽

pp. 265-273 ◽

Cited By ~ 29

Author(s):

P.O. Byrne ◽

P.R. Sisson ◽

P.D. Oliver ◽

H.R. Ingham

Keyword(s):

Carbon Dioxide ◽

Laser Irradiation ◽

Carbon Dioxide Laser

Download Full-text

In vitro effects of low level yellow laser irradiation on human red blood cells

2016 IEEE 6th International Conference on Photonics (ICP) ◽

10.1109/icp.2016.7510024 ◽

2016 ◽

Author(s):

Mustafa S. Al Musawi ◽

M.S. Jaafar ◽

B.T. Al-Gailani ◽

Naser M. Ahmed ◽

Fatanah M. Suhaimi

Keyword(s):

Red Blood Cells ◽

Laser Irradiation ◽

Blood Cells ◽

Low Level ◽

Human Red Blood Cells ◽

Yellow Laser ◽

In Vitro Effects

Download Full-text

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.

Download Full-text

Profiling of Cytokines Secreted by Conventional Aqueous Outflow Pathway Endothelial Cells Activated In Vitro and Ex Vivo With Laser Irradiation

Investigative Opthalmology & Visual Science ◽

10.1167/iovs.15-17660 ◽

2015 ◽

Vol 56 (12) ◽

pp. 7100 ◽

Cited By ~ 3

Author(s):

Jorge A. Alvarado ◽

Phuonglan Chau ◽

Jianfeng Wu ◽

Richard Juster ◽

Amde Selassie Shifera ◽

...

Keyword(s):

Endothelial Cells ◽

Laser Irradiation ◽

Ex Vivo ◽

Outflow Pathway ◽

Aqueous Outflow

Download Full-text

Impact of refrigeration on the surface hardness of hybrid and microfilled composite resins

Brazilian Dental Journal ◽

10.1590/s0103-64402009000100007 ◽

2009 ◽

Vol 20 (1) ◽

pp. 42-47 ◽

Cited By ~ 4

Author(s):

Fernando Henrique Ruppel Osternack ◽

Danilo Biazzetto de Menezes Caldas ◽

Rodrigo Nunes Rached ◽

Sérgio Vieira ◽

Jeffrey A. Platt ◽

...

Keyword(s):

Room Temperature ◽

Surface Hardness ◽

In Vitro Study ◽

Knoop Hardness ◽

Composite Resins ◽

Bottom Surface ◽

Steel Mold ◽

Polymerization Condition ◽

Post Hoc

This in vitro study evaluated the Knoop hardness of the composite resins Charisma® (C) and Durafill VS® (D) polymerized in 3 different conditions: at room temperature (A) (23 ± 1°C); refrigerated at 4 ± 1°C and immediately photo-activated after removal from the refrigerator (0); and, refrigerated at 4 ± 1°C and photo-activated after a bench time of 15 min at room temperature (15). One hundred and twenty specimens (4 mm diameter and 2 mm depth) were made using a stainless steel mold and following manufacturer's instructions. All specimens were tested immediately after polymerization (I) and after 7 days of water storage in the dark at room temperature (7d). The data were subjected to ANOVA and post-hoc Tukey's test (a=0.05). On the top surface, CAI was statistically similar to C15I and DAI to D15I (p>0.05). On the bottom surface, CAI presented higher hardness values when compared to COI and C15I (p<0.05). The D groups showed no significant differences (p>0.05) on the bottom surfaces for any tested polymerization condition. After 7 days of storage, the Knoop hardness decreased significantly (p<0.05) for groups C7d and D7d except for C07d, which was not different from COI at either surface (p>0.05). D07d showed higher Knoop hardness (p<0.05) values on the top surface when compared to the other groups.

Download Full-text

Formation of pressure waves during in vitro excimer laser irradiation in whole blood and the effect of dilution with contrast media and saline

Lasers in Surgery and Medicine ◽

10.1002/lsm.1900140104 ◽

1994 ◽

Vol 14 (1) ◽

pp. 3-6 ◽

Cited By ~ 16

Author(s):

Andreas Baumbach ◽

Karl K. Haase ◽

Carsten Rose ◽

Martin Oberhoff ◽

Hartmut Hanke ◽

...

Keyword(s):

Contrast Media ◽

Laser Irradiation ◽

Excimer Laser ◽

Whole Blood ◽

Pressure Waves ◽

Excimer Laser Irradiation

Download Full-text

Bactericidal Effects of Diode Laser Irradiation on Enterococcus faecalis Using Periapical Lesion Defect Model

ISRN Dentistry ◽

10.5402/2011/870364 ◽

2011 ◽

Vol 2011 ◽

pp. 1-6 ◽

Cited By ~ 11

Author(s):

Masato Nagayoshi ◽

Tatsuji Nishihara ◽

Keisuke Nakashima ◽

Shigetsugu Iwaki ◽

Ker-Kong Chen ◽

...

Keyword(s):

Laser Irradiation ◽

Diode Laser ◽

Enterococcus Faecalis ◽

Periapical Lesion ◽

Lesion Area ◽

Defect Model ◽

Cytotoxic Effects ◽

Periapical Lesions ◽

Bactericidal Effects

Objective. Photodynamic therapy has been expanded for use in endodontic treatment. The aim of this study was to investigate the antimicrobial effects of diode laser irradiation on endodontic pathogens in periapical lesions using an in vitro apical lesion model. Study Design. Enterococcus faecalis in 0.5% semisolid agar with a photosensitizer was injected into apical lesion area of in vitro apical lesion model. The direct effects of irradiation with a diode laser as well as heat produced by irradiation on the viability of microorganisms in the lesions were analyzed. Results. The viability of E. faecalis was significantly reduced by the combination of a photosensitizer and laser irradiation. The temperature caused by irradiation rose, however, there were no cytotoxic effects of heat on the viability of E. faecalis. Conclusion. Our results suggest that utilization of a diode laser in combination with a photosensitizer may be useful for clinical treatment of periapical lesions.

Download Full-text