Effects of treatment for manipulation of teeth and Er:YAG laser irradiation on dentin: a Raman spectroscopy analysis.

Biomedic Vibrational Spectroscopy Laboratory, Research and Development Institute, Universidade do Vale do Paraíba (UNIVAP), São José dos Campos, Brazil.
Photomedicine and Laser Surgery (Impact Factor: 1.58). 03/2007; 25(1):50-7. DOI: 10.1089/pho.2006.1020
Source: PubMed

ABSTRACT The main purpose of this study was to evaluate the utility of Raman spectroscopy analysis as a research tool to study the effects of Er:YAG laser etching on dentin mineral and organic components. A secondary aim was to study the effects of the decontamination process and the storage procedure on dentin components.
There are no spectroscopy reports relating the effects of Er:YAG laser irradiation as an alternative to acid etching and the manipulation process on the dentin structure.
Twelve non-carious human third molars were divided in two main groups: stored in thymol solution (group A, n = 6) or autoclaved (group B, n = 6). The specimens were either etched with 37% phosphoric acid (control subgroup) or irradiated with Er:YAG laser. Irradiated samples were divided into the following subgroups: I, II, and III (80 mJ, 3 Hz, 30 sec; 120 mJ, 3 Hz, 30 sec; and 180 mJ, 3 Hz, 30 sec, respectively). Samples were analyzed by Raman spectroscopy.
The mineral and organic dentin contents were more affected in autoclaved teeth than in the specimens stored in thymol. Peak area reduction in group A specimens treated with phosphoric acid and pulse energy of 80 mJ were the most conservative surface treatments regarding changes in the peak area of organic and inorganic dentin components.
The autoclaving process and pulse energies of 120 and 180 mJ produced greater reduction of organic and inorganic contents in dentin, associated with greater reduction in the areas of 968, 1077, 1460, and 1670 cm(1) Raman peaks.

  • [Show abstract] [Hide abstract]
    ABSTRACT: This study evaluated the effect of combining laser irradiation with fluoride on an enamel microstructure and demineralization by FT-Raman spectroscopy (FTRS). Eighty human enamel slabs were divided into eight groups: (G1) untreated; (G2) acidulated phosphate fluoride application (APF—1.23% F− for 4 min); (G3) Nd:YAG irradiation (84.9 J cm−2, 60 mJ/pulse); (G4) Nd:YAG + APF; (G5) APF + Nd:YAG; (G6) Er,Cr:YSGG irradiation (2.8 J cm−2, 12.5 mJ/pulse); (G7) Er,Cr:YSGG + APF; and (G8) APF + Er,Cr:YSGG. After treatment, the samples were submitted to a ten-day pH-cycling model. Chemical changes were determined on the slabs before and after treatment, and also after pH-cycling, by FTRS in the range 400−4000 cm−1. The inorganic bands at 440, 590, 870, 960, 1100 cm−1, and the organic bands at 1270, 1450, 1670, 2945 cm−1 were considered. Demineralization promoted reduction in organic contents; Nd:YAG laser irradiation promoted loss of carbonate and organic content, while Er,Cr:YSGG did not produce significant changes in the relative band intensities of organic and inorganic contents of the enamel. In lased samples, no effects caused by pH-cycling on enamel were observed. In conclusion, laser treatment and its association with fluoride can somehow interfere with the demineralization dynamics, reducing its effects over the enamel.
    Laser Physics 02/2014; 24(3):035603. DOI:10.1088/1054-660X/24/3/035603 · 1.03 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective: The aim of this study was to evaluate the influence of cavity preparation and restorative materials containing fluorides in the prevention of secondary caries lesion development in situ. Methods: A total of 120 blocks obtained from human teeth were divided into two groups and standardized cavities were prepared using diamond burs (DB) or Er,Cr:YSGG-laser [20 Hz, 4.0W, 55% water, 65% air (LA)]. They were divided into three subgroups according to the restorative material (n=20): glass-ionomer cement (GI), resin modified glass-ionomer (RM) or composite resin (CR). Blocks were fixed in palatal intra-oral appliances worn in situ by 20 human volunteers, who dropped 20% sucrose solution eight times daily. After 21 days, blocks were removed and restorations were cross-sectioned to evaluate microhardness [Knoop hardness number (KHN)] underneath enamel surface from 30 to 200 μm. Factors "cavity preparation," "restorative materials," and "depth" were evaluated by three way ANOVA, followed by Tukey test (p<0.05). Results: The results showed lower microhardness in cavities prepared with DB than in cavities prepared with LA. At 30 μm, there were no statistical significant differences with regard to "cavity preparation" or "restorative materials" factors. In depth evaluation, the enamel microhardness progressively increased as a function of depth for the GI groups. In the groups prepared with LA at 60 μm/90 μm, there were no significant differences between GI and RM materials, whose microhardnesses were significantly higher than that of CR. Conclusions: Cavity preparation using Er,Cr:YSGG laser increases caries resistance of enamel walls, and reduce caries lesion depth development regardless of fluoride presence in the restorative material. CR showed higher caries lesion development than GI, and RM showed intermediate results.
    Photomedicine and Laser Surgery 02/2015; 33(2). DOI:10.1089/pho.2014.3815 · 1.58 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Dental students use extracted human teeth to learn practical and technical skills before they enter the clinical environment. In the present research, knowledge, performance, and attitudes toward sterilization/disinfection methods of extracted human teeth were evaluated in a selected group of Iranian dental students. In this descriptive cross-sectional study the subjects consisted of fourth-, fifth- and sixth-year dental students. Data were collected by questionnaires and analyzed by Fisher's exact test and Chi-squared test using SPSS 11.5. In this study, 100 dental students participated. The average knowledge score was 15.9 ± 4.8. Based on the opinion of 81 students sodium hypochlorite was selected as suitable material for sterilization and 78 students believed that oven sterilization is a good way for the purpose. The average performance score was 4.1 ± 0.8, with 3.9 ± 1.7 and 4.3 ± 1.1 for males and females, respectively, with no significant differences between the two sexes. The maximum and minimum attitude scores were 60 and 25, with an average score of 53.1 ± 5.2. The results of this study indicated that knowledge, performance and attitude of dental students in relation to sterilization/disinfection methods of extracted human teeth were good. However, weaknesses were observed in relation to teaching and materials suitable for sterilization.
    Dental research journal 03/2013; 10(4):482-488.

Full-text (2 Sources)

Available from
Jun 4, 2014