The purpose of this study was to compare the compositional changes and microhardness of the cavity floor prepared by erbium, chromium:yttrium–scandium–gallium–garnet (Er,Cr:YSGG) laser irradiation ...with those of the conventional bur-prepared cavity. A total of 16 extracted human molar teeth (with no carious lesions or repairs) were selected for this study. On the buccal and lingual (palatal) surfaces of each tooth, cavities (diameter 3 mm, depth 2 mm) were prepared with an Er,Cr:YSGG laser system (Waterlase MD
TM
, USA) and high-speed turbine. The cavities were cross-sectioned and subjected to atomic analysis by scanning electron microscopy–energy dispersive X-ray spectrometry (SEM-EDX) and Vickers hardness test. Statistical analyses were performed with
t
-tests. Surface characteristics of the prepared cavities were also investigated by SEM. No significant differences were found between the calcium/phosphorus (Ca/P) ratio and Vickers hardness of laser- and bur-prepared cavities. The SEM observation revealed that the lased cavity surface was irregular, and there was also an absence of smear layer; the orifices of dentinal tubules were exposed. Microhardness measurement of the cavity floor confirmed that the Er,Cr:YSGG laser produced a clean-cut surface of the cavity.
The aim of this study is to assess the apical microleakage of the composite filled root-end cavities prepared by an Erbium, Chromium: Yttrium-Scandium-Gallium-Garnet laser. Fifty-five maxillary ...incisor teeth were enlarged and filled. Following the apical resection, root-end cavities were prepared using conventional methods: either using a bur (
n
= 30) or an ultrasonic retrotip (
n
= 15). Root-end cavities of the 15 teeth in the bur group were finished with the laser at 3.5 W. All root-end cavities were filled using two-step self-etching primer and composite resin. After 4 months of storage, apical microleakage was measured by a fluid filtration method. Microleakage of composite filled root-end cavities that were prepared by Er, Cr: YSGG was significantly larger than those made by conventional methods (
p
< 0.05). In conclusion, using the Er, Cr: YSGG laser has no advantages over conventional root-end cavity preparation methods when a composite filling material is used to seal root-end cavities.
The purpose of this study was to investigate the tensile bond strength of composite inlays to human dentin with two different cavity preparation tools (bur versus Er, Cr: YSGG laser) and with two ...different bonding procedures (total-etch: Variolink II versus self-etch: Maxcem). The specimens were divided into four groups: bur-cut/Variolink II, bur-cut/Maxcem, laser-ablated/Variolink II, and laser-ablated/Maxcem. The following characteristics were then investigated: morphological change, dentin-resin cement interface, surface roughness, and tensile bond strength. Results demonstrated that the tensile bond strengths of the four groups were 19.11±5.88 MPa, 8.54±2.38 MPa, 13.72±3.43 MPa, and 12.11±3.71 MPa, respectively. We concluded that Variolink II provided higher tensile bond strength to composite inlays than Maxcem. On the other hand, the bond strength of Variolink II with dentin cavity prepared by Er, Cr: YSGG laser was statistically lower than that prepared by bur.
This preliminary study was to investigate in vitro the Er,Cr:YSGG laser ablation capability, both range (enlargement aspects of laser tips corresponded to conventional endodontic files) and quality ...(removing of smear layer and opening of dentinal tubules) to clean and shape the root canal for final obturation step. The crowns of 15 extracted multi-rooted posterior human teeth were resected, and then 15 canals were prepared by an Er,Cr:YSGG laser up to 1.5 W (actual power output) using the step-back technique, while the other 15 canals (control) were enlarged conventionally by K-flex file. The results revealed that posterior root-canal preparation could be achieved by laser beam transmitted to the canal using endodontic tips. At a chosen significance level of
α
= 1%, the results showed no significant statistical difference between the two groups (
P
> 0.01). Considering the results of this current study, laser-based root-canal preparation still shows certain limitations, and further improvements are mandatory for higher achievement and better preparation outcomes.
Purpose: The purpose of this study was to evaluate the effect of the Er,Cr:YSGG laser on the enamel's acid resistance when irradiated alone, prior to or after acidulated phosphate fluoride (APF) ...treatment. Methods: Eighty-five enamel surfaces were prepared from 17 extracted
human premolars and randomly assigned to 5 groups: (1) untreated (control); (2) irradiated with a Er,Cr:YSGG laser; (3) exposed to a 1.23% APF gel; (4) laser-irradiated followed by APF treatment; and (5) APF-treated followed by laser irradiation. The specimens were individually demineralized
in 0.2 M acetate buffer solution for 10 days, and the acid resistance was evaluated by determining the calcium ion using atomic absorption spectrometry. Results: Significant differences were found between group 1 and groups 2 through 5 (P<0.001). There were no significant differences
between groups 2 and 3 (P=1.000). Compared to groups 2 and 3, a lower calcium content was detected in the demineralization solution for groups 4 and 5. The difference between groups 4 and 5, however, was not statistically significant (P=0.289). Conclusions: Combining acidulated phosphate
fluoride with the Er,Cr:YSGG laser decreased the enamel demineralization more than either fluoride treatment or laser treatment alone.
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