scholarly journals Microhardness, Structure, and Morphology of Primary Enamel after Phosphoric Acid, Self-Etching Adhesive, and Er:YAG Laser Etching

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
María del Carmen Zoila Alcantara-Galeana ◽  
Rosalía Contreras-Bulnes ◽  
Laura Emma Rodríguez-Vilchis ◽  
Manuel Eduardo Espinosa-Pesqueira ◽  
Cecilia Carlota Barrera-Ortega ◽  
...  

Background. Phosphoric acid is the traditional etching agent; self-etching adhesives and Er:YAG laser are alternative methods. Knowledge of deciduous enamel etching is required.Aim. To evaluate primary enamel microhardness, structure, and morphology after phosphoric acid, self-etching, and Er:YAG laser etching.Design. Seventy primary incisors were assigned to five groups (n=14): I (control), II (35% phosphoric acid), III (self-etching adhesive), IV (Er:YAG laser at 15 J/cm2), and V (Er:YAG laser at 19.1 J/cm2). Microhardness was evaluated by Vickers indentation. Chemical composition was analyzed by energy dispersive X-ray spectroscopy and morphological changes by scanning electron microscopy. One-way ANOVA, Kruskal–Wallis, Mann–WhitneyU, and Pearson bivariate correlation were employed (α=0.05).Results. Vickers microhardness showed differences and no correlation with Ca/P ratio. Group II showed differences in carbon, oxygen, and phosphorus atomic percent and group V in Ca/P ratio. Morphological changes included exposed prisms, fractures, craters, and fusion.Conclusions. Enamel treated with phosphoric acid showed different chemical characterization among groups. Self-etching and Er:YAG laser irradiation at 19.1 J/cm2showed similar microhardness and chemical characterization. Er:YAG laser irradiation at 15 J/cm2maintained microhardness as untreated enamel. Er:YAG laser irradiation at 19.1 J/cm2enhanced mineral content. Morphological retentive changes were specific to each type of etching protocol.

1999 ◽  
Vol 17 (1) ◽  
pp. 7-12 ◽  
Author(s):  
HIROAKI TOKONABE ◽  
RYO KOUJI ◽  
HARUJI WATANABE ◽  
YUKIO NAKAMURA ◽  
KOUKICHI MATSUMOTO

2013 ◽  
Vol 83 (6) ◽  
pp. 973-980 ◽  
Author(s):  
Serkan Sağır ◽  
Aslıhan Usumez ◽  
Ebru Ademci ◽  
Serdar Usumez

ABSTRACT Objective: To compare the effect of laser irradiation at two different pulse settings and acid etching on the shear bond strength (SBS) of orthodontic brackets to enamel. Materials and Methods: Thirty-six premolars were allocated to three groups (n  =  12): (1) 37% phosphoric acid etching, (2) erbium-doped yttrium aluminum garnet (Er:YAG) laser etching with medium-short pulse mode (MSP; 100 µs, 120 mj, 10 Hz, 1.2 W), and (3) Er:YAG laser etching with quantum-square pulse mode (QSP; 120 mj, 10 Hz, 1.2 W). Metallic brackets were bonded with Transbond XT. After photopolymerization, the samples were subjected to 5000 thermal cycles and debonded with a universal testing machine, and the SBS values were recorded. Surface morphology was evaluated with profilometric examination, scanning electron microscopy, and atomic force microscopy. The adhesive remnant index (ARI) was evaluated to assess the remaining adhesive. Results: The results of SBS testing were analyzed by one-way analysis of variance and Tukey honestly significant diffference tests. The mean SBS values of QSP and MSP laser groups were 11.80 ± 2.7 MPa and 10.10 ± 4.5 MPa, respectively, and the QSP group demonstrated significantly higher SBS (P < .01) than that of the acid-etched group (6.6 ± 2.4 MPa). No significant difference was observed between the SBS values of the two laser groups (P < .05). The difference between the ARI scores of the laser groups and the acid-etched group was statistically significant (P < .05). Conclusion: Laser etching at MSP and QSP modes present successful alternatives to acid etching; however, long-term clinical studies are required to verify clinical success.


2008 ◽  
Vol 19 (1) ◽  
pp. 57-61 ◽  
Author(s):  
Luis H. Sasaki ◽  
Paulo D. C. Lobo ◽  
Yumi Moriyama ◽  
Ii-Sei Watanabe ◽  
Antonio B. Villaverde ◽  
...  

Er:YAG laser has been studied as a potential tool for restorative dentistry due to its ability to selectively remove oral hard tissue with minimal or no thermal damage to the surrounding tissues. The purpose of this study was to evaluate in vitro the tensile bond strength (TBS) of an adhesive/composite resin system to human enamel surfaces treated with 37% phosphoric acid, Er:YAG laser (lambda=2.94 mum) with a total energy of 16 J (80 mJ/pulse, 2Hz, 200 pulses, 250 ms pulse width), and Er:YAG laser followed by phosphoric acid etching. Analysis of the treated surfaces was performed by scanning electron microscopy (SEM) to assess morphological differences among the groups. TBS means (in MPa) were as follows: Er:YAG laser + acid (11.7 MPa) > acid (8.2 MPa) > Er:YAG laser (6.1 MPa), with the group treated with laser+acid being significantly from the other groups (p=0.0006 and p= 0.00019, respectively). The groups treated with acid alone and laser alone were significantly different from each other (p=0.0003). The SEM analysis revealed morphological changes that corroborate the TBS results, suggesting that the differences in TBS means among the groups are related to the different etching patterns produced by each type of surface treatment. The findings of this study indicate that the association between Er:YAG laser and phosphoric acid can be used as a valuable resource to increase bond strength to laser-prepared enamel.


1999 ◽  
Vol 17 (3) ◽  
pp. 105-109 ◽  
Author(s):  
MOZAMMAL HOSSAIN ◽  
YUKIO NAKAMURA ◽  
YOSHISHIGE YAMADA ◽  
YUICHI KIMURA ◽  
GEN NAKAMURA ◽  
...  

2003 ◽  
Vol 21 (1) ◽  
pp. 7-17 ◽  
Author(s):  
Tomoko Matsuyama ◽  
Akira Aoki ◽  
Shigeru Oda ◽  
Takayuki Yoneyama ◽  
Isao Ishikawa

CIRP Annals ◽  
2011 ◽  
Vol 60 (1) ◽  
pp. 555-558 ◽  
Author(s):  
T. Furumoto ◽  
T. Ueda ◽  
A. Kasai ◽  
A. Hosokawa

Author(s):  
Katharina Kuhn ◽  
Carmen U. Schmid ◽  
Ralph G. Luthardt ◽  
Heike Rudolph ◽  
Rolf Diebolder

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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