Adriana Bona Matos

University of São Paulo, San Paulo, São Paulo, Brazil

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Publications (31)21.99 Total impact

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    ABSTRACT: Objective: This in vitro study aimed to microscopically evaluate the use of different conditioning parameters of a new Er: YAG laser. This device introduces a new technology that enable the control of the pulse duration, promoting pulse durations much smaller than previous ones, called ssp (super short pulse), in which the effective irradiation time can be decreased to 50 µs, providing twice the time of rest and generating cold ablation. Method: The Er:YAG laser (Fidelis III, Fotona, Slovenia) with 50 µs pulse duration (SSP) was used in this study. Eight dentin disks were divided into four groups (n = 2): G1- 80 mJ/2 Hz; G2- 70 mJ/10 Hz; G3- 60 mJ/10 Hz and G4- 50 mJ/10 Hz. After irradiation, specimens were processed for analysis by scanning electron microscopy (SEM). Result: Group G1 (80 mJ/2 Hz) showed an irregular irradiated dentin, the vast majority of open dentin tubules with increased diameter, peritubular dentin easily detectable. Groups G2 and G3 (70 mJ/10 Hz and 60 mJ/10 Hz) showed an smooth irregular irradiated dentin, the vast majority of open dentin tubules with increased diameter, peritubular dentin easily detectable. Group G4 (50 mJ/10 Hz) showed dentin surface irradiated quite irregular, presence of opened and closed dentinal tubules with smaller diameter, peritubular dentin easily detectable. Conclusion: All laser experimental groups were able to condition the dentin surface, however showed distinct characteristics that should be investigated further with relation to the effect of bond strenght to composite resin with this new laser technology.
    IADR General Session and Exhibition 2014; 06/2014
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    ABSTRACT: Aim: This study evaluated and improved a protocol for obtaining standard caries-affected dentin (CAD) by Streptococcus mutans bioflm demineralization process. Materials and methods: Forty-eight human molars were divided in six experimental groups, according to: period of cariogenic challenge (7, 14 or 21 days) and type of dentin (erupted or unerupted teeth). After complete cariogenic challenge sound and CAD dentin were evaluated by: visual inspection (VI), digital radiography (DR), optical coherence tomography (OCT) and laser fuorescence (LF). Results: Visual inspection confrmed the formation of CAD based on tissue yellowing and loss of surface gloss. Digital radio- graphy detected the presence of radiolucent images, suggesting caries. Three calibrated examiners viewed all images obtained by VI and DR and were able to distinguish healthy from CAD. Fisher's exact statistical test (p < 0.05) confrmed no difference between groups by VI (G1/G4: p = 0.6; G2/G5: p = 1; G3/G6: p = 1) or DR (G1/G4: p = 1; G2/G5: p = 1; G3/G6: p = 1). Both LF values and demineralization depth, as determined by OCT, were subjected to ANOVA (p < 0.05). For LF, a statistically signifcant difference was observed for the type of substrate (p = 0.001). For OCT, no statistically signifcant differences in the type of substrate (p = 0.163), length of cariogenic challenge (p = 0.512) or interaction between factors (p = 0.148) were observed. Scanning electron micrographs confrmed the presence of CAD; a more uniform demineralization surface was observed in the dentin of unerupted teeth. Conclusion: This protocol suggests that standard CAD can be obtained in 7 days of cariogenic challenge using unerupted teeth. Clinical signifcance: With the new perspective on the clinical treatment of caries lesions, bonding is increasingly performed to demineralize CAD, which is susceptible to remineralization. A useful protocol to standardize the production of CAD, by microbiological cariogenic challenge, would be an important contribution to laboratorial test in the feld of operative dentistry. Keywords: Dental caries, Diagnosis, Caries-affected dentin, Laboratory research. How to cite this article: Azevedo CS, Garbui BU, Silva CM, Simionato MRL, Freitas AZ, Matos AB. Obtaining Artifcially Caries-affected Dentin for in vitro Studies. J Contemp Dent Pract 2014;15(1):12-19. Source of support: Grants Fapesp/2010/10126-3 and 2010/ 12910-3. Confict of interest: None.
    The journal of contemporary dental practice 01/2014; 15(1):12-19.
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    ABSTRACT: Abstract Objective: The purpose of this study was to evaluate the bond strength (BS) of different surface treatments, including laser irradiation, between conventional glass ionomer cement (GIC) and dentine. Methods: Eighty-five human third molars were divided into five groups with one of the following treatments: G1- control group, had no treatment; G2, G3, and G4 were treated with Er,Cr:YSGG laser irradiation at 0.5 W, 20 Hz, 25 mJ, 9 J/cm(2) (G2); 1.0 W, 20 Hz, 50 mJ, 18 J/cm(2)(G3); and 1.5 W, 20 Hz, 75 mJ, 27 J/cm(2) (G4); and G5 was treated with GIC liquid, which contains polyacrylic acid. Scanning electron microscopy (SEM) evaluation (n=2) and micro-shear bond strength test (n=15) using the GIC bonded to dentine were performed after 24 h of water immersion. The data were analyzed by one way analysis of variance (ANOVA), according to irradiation protocol (p<0.001). Results: G2 specimens presented the highest BS results (in MPa) (10.50±0.84), followed by G1 (4.77±0.59) and G5 (4.26±1.02), which were statistically similar. G3 (3.32±0.39) and G4 (2.94±0.50) demonstrated the lowest BS values, and the difference between these groups was not statistically significant (p>0.001). SEM analysis of G1 revealed that the smear layer covered the entire dentine surface, whereas in G2, G3, and G4, irregular dentine was detected with open dentinal tubules and protruded peritubular dentine. Laser pulses could easily be distinguished in G2 but not in G3 and G4. G5 revealed a thin smear layer with dentinal tubule apertures clearly detectable. Conclusions: Dentine treatment with an Er,Cr:YSGG laser irradiation at a power of 0.5 W increased the BS of conventional GIC.
    Photomedicine and laser surgery 09/2013; 31(9):453-60. · 1.76 Impact Factor
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    ABSTRACT: Aim: To evaluate the leakage on Er,Cr:YSGG laser-and bur-prepared Class V cavities restored with a silorane-based composite resin using different insertion techniques Methods: 40 cavities were outlined according to: the type of instrument [Er,Cr:YSGG laser (3.0 W power, energy per pulse of 150 mJ, fluence of 53.57J/cm 2 , pulse duration of 140-200 µs, 20 Hz repetition rate and 55/65% air/water spray) or diamond bur]; and the type of filling technique (bulk increment or incremental). Four experimental groups were obtained (n=10): G1-diamond bur (DB) and incremental (I); G2-DB and bulk increment (BI); G3-Er,Cr:YSGG and I; and G4-Er,Cr:YSGG and BI. Specimens were restored with a silorane-based composite resin (Filtek P90, 3M/ESPE), subjected to 500 thermal cycles, sealed, infiltrated with 2% (w/v) methylene blue and sectioned in halves. Specimen analysis was scored based on a scale. Statistical analyses were done using the Kruskal-Wallis and Student Newman-Keuls tests (α=0.05). Results: Statistically significant differences were observed between G2 and G4 (p=0.003) and between G1 and G2 (p=0.028). The filling technique did not influence the pattern of dye leakage in the cavity walls (p=0.151). Conclusions: Less leakage was observed when Er,Cr:YSGG cavities were restored with silorane-based composite resin, using the bulk increment technique. Nevertheless, cavities done using diamond bur have less leakage only when incrementally restored.
    Brazilian Journal of Oral Sciences 06/2013; 12:119-124.
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    ABSTRACT: Objective: The aim of this in vitro study was to obtain standard caries affected-dentine by dentin demineralization process induced by Streptoccocus mutans biofilm (microbiological approach). Method: The method validation was performed by optical coherence tomography (OCT), visual inspection, laser fluorescence (DIAGNOdent) and digital intra-oral radiography (DIOR). As all methods did not destruct samples, all tests were performed in the same specimens. Human molars were grounded in the occlusal surface to remove enamel and obtain a flat dentin surface. Specimens were protected with nail varnish in half of the occlusal surface (control), before microbiological challenge (n=28/group) for 3 different period of immersion in the artificial caries solution: 7 (group 1), 14 (group 2) e 21 (group 3) days. At first, artificially induced caries were visually inspected and photographed, digital radiographs were taken and diagnodent values were recorded. OCT images were obtained and also lesion depth was recorded. Result: For OCT (p=0.524) and DIAGNOdent (p=0.166), data were subjected to ANOVA test at a 5% of significance, statistical analysis revealed no significant difference between G1, G2 and G3. Qualitative results (visual inspection and DIOR) indicated that sound dentin could always be distinguished from caries-affected dentin after 7 days of demineralization challenge. Conclusion: In conclusion, a seven-day demineralization period can be considered sufficient to obtain artificially induced caries-affected dentin for laboratory experimental purpose.
    IADR General Session 2012; 06/2012
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    Contemporary Approach to Dental Caries, 03/2012; , ISBN: 978-953-51-0305-9
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    ABSTRACT: This study aimed to evaluate the chemical interaction of collagen with some substances usually applied in dental treatments to increase the durability of adhesive restorations to dentin. Initially, the similarity between human dentin collagen and type I collagen obtained from commercial bovine membranes of Achilles deep tendon was compared by the Attenuated Total Reflectance technique of Fourier Transform Infrared (ATR-FTIR) spectroscopy. Finally, the effects of application of 35% phosphoric acid, 0.1M ethylenediaminetetraacetic acid (EDTA), 2% chlorhexidine, and 6.5% proanthocyanidin solution on microstructure of collagen and in the integrity of its triple helix were also evaluated by ATR-FTIR. It was observed that the commercial type I collagen can be used as an efficient substitute for demineralized human dentin in studies that use spectroscopy analysis. The 35% phosphoric acid significantly altered the organic content of amides, proline and hydroxyproline of type I collagen. The surface treatment with 0.1M EDTA, 2% chlorhexidine, or 6.5% proanthocyanidin did not promote deleterious structural changes to the collagen triple helix. The application of 6.5% proanthocyanidin on collagen promoted hydrogen bond formation.
    Journal of Biomedical Materials Research Part B Applied Biomaterials 01/2012; 100(4):1009-16. · 2.31 Impact Factor
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    ABSTRACT: This study was undertaken to examine the effect of root canal (RT) sealers content and the cleaning procedure of RT walls on bond strength (BS) of a fiber reinforced composite (FRC) post cemented with resin-based or zinc phosphate cement. Forty bovine roots were divided into 2 groups (n = 20) and obturated with gutta-percha points plus Sealer 26 sealer or gutta-percha points plus N-Rickert sealer. In each group, half (n = 10) of intracanal walls was cleaned with ethanol and the other half with sulfuric ether. In each of these subgroups, half of intracanal posts (n = 5) were cemented with Bistite resin-based cement and half with zinc phosphate cement. Specimens were submitted to pull-out test and tensile force until post dislodgement. The maximum forces required for post removal was expressed in MPa, means were submitted to statistical analysis (Analysis of Variance Test, a = 0.05). Fiber reinforced composite cemented with zinc phosphate were significantly more retentive than those cemented with Bistite (p < 0.05). Regarding the influence of eugenol-based sealer on post retention, there was a statistically significant difference (p < 0.05) only between groups cemented with Bistite, in which canals filled with N-Rickert + gutta-percha showed lower BS than canals filled with Sealer 26 + gutta-percha. Despite endodontic cement used, higher pull-out bond strength were obtained when posts were cemented with zinc phosphate. Clinical significance: The importance of ethanol or sulphuric ether application to properly replace water from intraradicular dentine still requires further investigations, especially to clarify if this technique may reduce the effect of aging and improve the stability of the bond, when used to cement fiber posts into the root canal.
    The journal of contemporary dental practice 01/2012; 13(3):275-9.
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    ABSTRACT: Aim: The aim of this study was to analyze and compare the influence of short-term NaOCl-storage and long-term water storage on the microtensile bond strength (µTBS) of etch-andrinse adhesive system to human dentin. Materials and methods: Thirty-six third human molars were randomly divided into 6 groups (n = 6) according to the aging protocol: G1 (water, 24 hours); G2 (water, 6 months); G3 (water, 12 months); G4 (10% sodium hypochlorite - NaOCl, 1 hour); G5 (10% NaOCl, 3 hours) and G6 (10% NaOCl, 5 hours). A two-step etch-and-rinse adhesive (Adper Single Bond 2) was applied according to the manufacturers' instructions. A composite (Filtek Z250) was applied in four horizontal increments and was individually cured. Specimens were cut following the microtensile test technique, submitted to the different aging protocols, and tested in tension. The fracture pattern was observed in a stereomicroscope (40* magnification) and in a scanning electron microscope. The µTBS data were analyzed by ANOVA and Tukey's test (α = 0.05). Results: The effect of storage in 10% NaOCl for 1 or 3 hours was not significantly different from that of aging in distilled water (DW) for 6 or 12 months (p > 0.05). Beams immersed in DW for 24 hours and in 10% NaOCl for 5 hours showed the highest and lowest µTBS values respectively. Conclusion: The aging protocols negatively influenced dentin bond strength. Aging specimens in 10% NaOCl for 1 or 3 hours can be an alternative method for long-term water storage (6 or 12 months) bond strength studies. Clinical significance: This aging protocol allows a quick achievement of longitudinal bond strength data, so that results are available to the professionals in this area while the materials are yet present at the dental market. Keywords: Laboratory research, Dental adhesive, Adhesion, Collagen, Dentin, Degradation, Durability, Microtensile bond test, Sodium hypochlorite. How to cite this article: Garbui BU, Botta SB, Reis AF, Matos AB. Comparison of Chemical Aging and Water Immersion Time on Durability of Resin-Dentin Interface produced by an Etchand- Rinse Adhesive. J Contemp Dent Pract 2012;13(4):464-471. Source of support: Nil Conflict of interest: None declared.
    The journal of contemporary dental practice 01/2012; 13(4):464-471.
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    ABSTRACT: The purpose of this study was to evaluate the degree of demineralization of artificially induced caries-affected human dentin by an in vitro microbiological method. The occlusal surfaces of 6 human molar teeth were abraded until a flat surface was obtained, and the enamel was removed to expose the occlusal dentin surface. These teeth were sectioned in 12 halves in the vestibular-lingual direction and divided into 3 groups according to the period length of the microbiological essay (n = 4): G1, 7 days; G2, 14 days; and G3, 21 days. The surfaces of all specimens were protected by an acid-resistant nail varnish, except for a window where the caries lesion was induced by a Streptoccocus mutans biofilm in a batch-culture model supplemented with 5% sucrose. The specimens were then analyzed by optical coherence tomography (OCT) with a super-luminescent light diode (Λ = 930 nm) with 6.0-µm lateral and longitudinal resolution (in the air). Qualitative and quantitative results (images and average dentin demineralization, respectively) were obtained. The mean demineralization depths were (µm) 235 ± 31.4, 279 ± 14, and 271 ± 8.3 in groups 1, 2, and 3, respectively. In addition, no significant change was observed in the lesion mean depth from 7 days of cariogenic challenge on. In conclusion, OCT was shown to be an efficient and non-invasive method to detect the depths of lesions caused by demineralization. Further, a seven-day demineralization time was considered sufficient for caries-affected dentin to be obtained.
    Brazilian oral research 10/2011; 25(5):407-13.
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    ABSTRACT: Objectives: Investigate the influence of proximal contact on the stress distribution in three-unit metal-ceramic and all-ceramic fixed partial dentures (FPD) models and anatomical structures by means of static loading in mathematical two-dimensional models using the finite element method (FEM). Methods: A sagittal image of a mandible was used to preprocess vectored images in MSC / PATRAN simulating a load of 100N divided among 17 points on the occlusal areas of a three-unit FPD, extending from the mandibular second premolar to the second molar. The creation of a proximal contact between the first premolar and the FPD was considered. In the pre-processing stage 5883 nodes were created with 11369 triangular elements. Four two-dimensional finite element models were created with the same boundary conditions: Models A (metal-ceramic) and B (all-ceramic) with proximal contact on the first premolar, and models C (metal-ceramic) and D (all-ceramic) without proximal contact. Results: In the two models without proximal contacts (C and D), the stress results (6.25 MPa) in the lower-middle portion of the mesial connector were around 50% lower than those found in the same region of models with proximal contacts. Increased stresses in the apical portion of the post, dentin and periodontal ligament showed the largest displacement of FPDs with the lack of proximal contact on the first premolar. Conclusion: The establishment of proximal contacts in mathematical models is a fundamental condition for true and reliable results, and the all-ceramic system presented a satisfactory mechanical behavior when compared with the metal-ceramic system.
    IADR General Session 2011; 03/2011
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    ABSTRACT: The aim of this study was to assess by atomic force microscopy (AFM) the effect of Er,Cr:YSGG laser application on the surface microtopography of radicular dentin. Lasers have been used for various purposes in dentistry, where they are clinically effective when used in an appropriate manner. The Er,Cr:YSGG laser can be used for caries prevention when settings are below the ablation threshold. Four specimens of bovine dentin were irradiated using an Er,Cr:YSGG laser (λ = 2.78 μm), at a repetition rate of 20 Hz, with a 750-μm-diameter sapphire tip and energy density of 2.8 J/cm(2) (12.5 mJ/pulse). After irradiation, surface topography was analyzed by AFM using a Si probe in tapping mode. Quantitative and qualitative information concerning the arithmetic average roughness (Ra) and power spectral density analyses were obtained from central, intermediate, and peripheral areas of laser pulses and compared with data from nonirradiated samples. Dentin Ra for different areas were as follows: central, 261.26 (±21.65) nm; intermediate, 83.48 (±6.34) nm; peripheral, 45.8 (±13.47) nm; and nonirradiated, 35.18 (±2.9) nm. The central region of laser pulses presented higher ablation of intertubular dentin, with about 340-760 nm height, while intermediate, peripheral, and nonirradiated regions presented no difference in height of peritubular and interperitubular dentin. According to these results, we can assume that even when used at a low-energy density parameter, Er,Cr:YSGG laser can significantly alter the microtopography of radicular dentin, which is an important characteristic to be considered when laser is used for clinical applications.
    Photomedicine and laser surgery 01/2011; 29(4):261-9. · 1.76 Impact Factor
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    ABSTRACT: The aim of this study was to detect the influence of (1) storage period of heparinized blood, (2) type of blood and presence of contaminant, (3) application mode of cleansing agents, and (4) efficacy of cleansing agents on contaminated enamel and dentin during the adhesion process of a one-step adhesive system. One hundred four human molars were sectioned into halves along the long axis for enamel and dentin tests. Heparinized and fresh blood were obtained from the same donor, applied and dried to maintain a layer of dry blood on the top of samples. The cleansing agents used were hydrogen peroxide, anionic detergent, and antiseptic solution. A one-step adhesive system (Clearfil S3 Bond) was applied on the dental surface, and composite resin cylinders were built up using Tygon tubing molds. After 24 h, the μSBS test (1 mm/min) and fracture analysis were performed. There was no statistically significant difference in bond strength values regarding the storage period of heparinized blood and the types of blood. Groups without contamination presented higher bond strengths than contaminated groups. The application mode of the cleansing agents had no influence on bond strength results. There was no statistically significant difference among cleansing agents and they were as effective as a water stream in counteracting the effect of blood contamination. Heparinized blood can be used as a contaminant for up to one week, and it is a reliable procedure to standardize the contaminant. The cleansing agents can be used without friction. A water stream is sufficient to remove blood contamination from dental tissues, before the application of a one-step adhesive system.
    The journal of adhesive dentistry 10/2010; 13(4):349-58. · 0.91 Impact Factor
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    ABSTRACT: Objective: The aim of this study was to evaluate the effect of different doses of gamma radiation (Gγ), produced from 60-Cobalt, on the mechanical properties of bovine enamel and dentin using the superficial microhardness test. Method: One hundred bovine teeth were randomly divided in 5 groups (n=20) to be sterilized with different doses of gamma radiation: G1 not sterilized; G2, G3, G4 and G5: sterilized using 18.4 kGy, 23.4 kGy, 25.0 kGy and 31.2 kGy, respectively. For analysis, all groups were divided in 2 subgroups (n=10) after irradiation: enamel (E) or dentin (D). The specimens were included in epoxy resin and polished (SiC gridding papers up to 600 grits). The Knoop surface microhardness was measured using 50.0g load for enamel and 15.0g load for dentin. For both substrates, indentation time was 5 seconds and were performed on buccal face at five locations in each specimen. Microhardness data were analyzed by ANOVA and Tukey test (α=5%). Results: The averages of microhardness values (kg/mm2) and standard deviations were: G1E (314.5435.57), G2E (300.7025.65), G3E (266.6220.02), G4E (265.3616.12), G5E (252.8823.84), G1D (60.3411.42), G2D (53.476.38), G3D (51.767.67), G4D (43.288.59) and G5D (39.905.78). Enamel microhardness significantly decreased when doses higher than 23.4 kGy were used (p<0.05), whereas doses higher than 25 kGy were necessary to change the dentin microhardness (p<0.01). Conclusion: Sterilization of teeth by gamma radiation can change enamel and dentin microhardness. Depending on the dose, sterilization of teeth with gamma radiation may alter the mineral phase of enamel and dentin, which should be considered before using sterilized teeth in research.
    IADR General Session 2010; 07/2010
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    ABSTRACT: To detect the influence of blood contamination (BC) on the bond strength (BS) of a self-etching bonding system (SES) to enamel and dentine. 25 human molars were longitudinally sectioned on the mesio-distal axis in order to obtain 50 specimens, which were embedded in acrylic resin. At first, the specimens were ground to expose a flat surface of enamel, and a bond strength test was performed. Afterwards, the samples were ground again in order to obtain a flat surface of dentine. Ten groups (total: n=100) were assigned according to substrate (enamel and dentine), step in the bonding sequence when contamination occurred (before the acidic primer and after the bonding resin), and contamination treatment (dry or rinse and dry procedure). Fresh human blood was introduced either before or after SES application (Clearfil SE Bond) and treated with air drying, or by rinsing and drying following application. Composite resin (Filtek Z-250,3M ESPE) was applied as inverted, truncated cured cones that were debonded in tension. The mean tensile BS values (MPa) for enamel/dentine were 19.4/23.0 and 17.1/10.0 for rinse-and-dry treatment (contamination before and after SES, respectively); while the measurements for the dry treatment, 16.2/23.3 and 0.0/0.0 contamination before and after SES, respectively. It was determined that blood contamination impaired adhesion to enamel and dentine when it occurred after bond light curing. Among the tested contamination treatments, the rinse-and-dry treatment produced the highest bond strength with BC after SES application, but it was not sufficient to recover the BS in the contamination-free group.
    European journal of dentistry. 07/2010; 4(3):280-6.
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    ABSTRACT: The purpose of this in vitro study was to test a new methodology to evaluate the effects of 35% hydrogen peroxide agent on the microtopography of sound enamel using an atomic force microscope (AFM). The buccal sound surfaces of three extracted human lower incisors were used, without polishing the surfaces to maintain them with natural morphology. These unpolished surfaces were subjected to bleaching procedure with 35% hydrogen peroxide that consisted of 4 applications of the bleaching agent on enamel surfaces for 10 min each application. Surface images were obtained in a 15 μm × 15 μm area using an AFM. The roughness (Ra and RMS) and the power spectral density (PSD) were obtained before and after the bleaching treatment. As results we could inquire that the PSD analyses were very suitable to identifying the morphological changes on the surfaces, while the Ra and RMS parameters were insufficient to represent the morphological alterations promoted by bleaching procedure on enamel. The morphological wavelength in the range of visible light spectrum (380–750 nm) was analyzed, showing a considerable increase of the PSD with the bleaching treatment.
    Applied Surface Science. 01/2010;
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    ABSTRACT: The objective of this in vitro study was to compare the degree of microleakage of composite restorations performed by lasers and conventional drills associated with two adhesive systems. Sixty bovine teeth were divided into 6 groups (n = 10). The preparations were performed in groups 1 and 2 with a high-speed drill (HD), in groups 3 and 5 with Er:YAG laser, and in groups 4 and 6 with Er,Cr:YSGG laser. The specimens were restored with resin composite associated with an etch-and-rinse two-step adhesive system (Single Bond 2 [SB]) (groups 1, 3, 4) and a self-etching adhesive (One-Up Bond F [OB]) (groups 2, 5, 6). After storage, the specimens were polished, thermocycled, immersed in 50% silver nitrate tracer solution, and then sectioned longitudinally. The specimens were placed under a stereomicroscope (25X) and digital images were obtained. These were evaluated by three blinded evaluators who assigned a microleakage score (0 to 3). The original data were submitted to Kruskal-Wallis and Mann-Whitney statistical tests. The occlusal/enamel margins demonstrated no differences in microleakage for all treatments (p > 0.05). The gingival/dentin margins presented similar microleakage in cavities prepared with Er:YAG, Er,Cr:YSGG, and HD using the etch-and-rinse two-step adhesive system (SB) (p > 0.05); otherwise, both Er:YAG and Er,Cr:YSGG lasers demonstrated lower microleakage scores with OB than SB adhesive (p < 0.05). The microleakage score at gingival margins is dependent on the interaction of the hard tissue removal tool and the adhesive system used. The self-etching adhesive system had a lower microleakage score at dentin margins for cavities prepared with Er:YAG and Er,Cr:YSGG than the etch-and-rinse two-step adhesive system.
    The journal of adhesive dentistry 06/2009; 11(3):221-9. · 0.91 Impact Factor
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    ABSTRACT: Objectives: The aim of this in vitro study was to evaluate the influence of saliva contamination during adhesion procedures. Methods: Forty-two (SEM-LV) and seventy (-TBS) human molars were used to perform this study. Experimental groups for enamel and dentin were divided as follows: no contamination (control G1and G8); contamination before primer (CBP) followed by rinse+dry (G2 and G9); CBP+ dry (G3 and G10); contamination after primer application (CAP)+dry (G4 and G11); CAP+ primer re-application (G5 and G12); contamination after photocuring of bonding resin (CABR) followed by rinsing and dry (G6 and G13); CABR + dry (G7 and G14). Self-etching adhesive system (Clearfil SE Bond) and composite resin (Clearfil AP-X) were used. Half of the specimens were tested after 24 hours of beam storage, while the other half was tested after 6 months. Separate statistical analyses were performed for enamel and dentin data (p<0.05). Results: Data obtained in 24 hours and after 6 months storage were, respectively: G1 (46.033.36 / 46.533.13); G2 (32.155.20 / 32.884.61); G3 (29.732.15 / 30.223.49); G4(30.402.47 / 30.511.78); G5(28.545.05 / 26.632.15); G6 (35.923.04 / 34.704.80); G7 (39.514.17 / 35.843.73); G8 (54.834.74 / 50.876.67); G9 (29.367.03 and 32.1212.20); G10 (35.415.39 / 33.2011.02); G11 (38.413.57 / 36.802.02); G12 (37.423.68 / 36.375.82); G13 (43.212.25 / 43.447.37); G14 (432.13 / 39.912.48). For both tested substrates, statistically significant differences were observed when control groups (no contamination) were compared to contaminated groups. All other tested variables were not statistically significant. Conclusions: Enamel and dentin SEM-LV evaluation detected the presence of the contaminant and/or its sub-product reaction only when saliva contamination occurred after primer and bonding resin application; saliva contamination is deleterious to adhesion; all efforts tested in order to counteract saliva contamination effects were not able to recover adhesion; and longitudinal evaluation did not show differences in adhesion after 6 months of storage.
    IADR General Session 2009; 04/2009
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    ABSTRACT: OBJECTIVE: This study investigated the surface micromorphology of healthy dentine before and after Er,Cr:YSGG laser application when irradiated with preventive purposes, using atomic force microscopy (AFM). METHODS: Five discs of bovine dentin were irradiated using an Er,Cr:YSGG laser (λ=2.78m), using a 750m diameter sapphire tip, at energy density of 2.8J/cm2 (12.5 mJ/pulse) and repetition rate of 20Hz. Before and after irradiation, surface topography was analyzed by AFM using a Si probe in tapping mode with a scan size of 80x80m2 in fixed resolution of 512x512 points at 1Hz. Quantitative and qualitative information concerning the power spectral density (PSD), roughness (Ra) and cross-section analysis were obtained from areas of the center and periphery of laser pulses and the non-irradiated regions of the same specimen. RESULTS: The dentinal roughness parameter (Ra) of center and periphery of laser pulses and of the non-irradiated regions was, respectively, 83.48(6.34)nm, 45.8(13.47)nm and 35.18(2.9)nm. The central region of laser pulses presented nodules between 30-45nm height and 0.8-2.2m width, the peripheral region presented nodules of 10-30nm height and 0.8-2.2m width, and the non-irradiated region presented no nodules. The PSD analysis of dentin demonstrated a contribution in the wavelengths between 0.8-2.2m of 2 times (p<0.05) compared to non-irradiated region and of 1.6 times (p<0.05) compared to pulse periphery region. The central region of laser pulses presented higher ablation of intertubular region, about 340-760nm height, while peripheral and non-irradiated regions presented no difference in height of inter-peritubular dentin. CONCLUSION: Even when used at sub-ablative parameter, Er,Cr:YSGG laser is able to promote a significant increase of dentin roughness, mainly at the pulse center, which is due to the ablation of intertubular region. Besides that, AFM technique is able to provide qualitative and quantitative information of the extension of the structural changes caused by laser irradiation on dentin. Supported by CAPES.
    IADR General Session 2009; 04/2009
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    ABSTRACT: OBJECTIVE: The purpose of this in vitro study was to test a new methodology to evaluate the effects of 35% hydrogen peroxide (Pola Office, SDI- Australia) agent on the micromorphology and surface roughness of sound enamel using an Atomic Force Microscope (AFM). METHODS: Enamel blocks (4 x 3 x 2 mm) were cut from the coronal part of human embedded third molar. No polishing was made on enamel surfaces to maintain them with natural roughness. The enamel blocks were treated with 35% hydrogen peroxide (HP). The bleaching procedure consisted of 4 applications of the agent on enamel surfaces for 10 minutes each. Surfaces images were obtained in 10X10m2 areas using an AFM to observe the topography and to determine the average roughness (Ra), root mean square (Rms) and power spectral density (PSD). The blocks were submitted to the same analyses before and after the bleaching procedure. The initial records were used as a control of each block. RESULTS: The PSD analysis allowed to identify the morphological changes on the surfaces and the Ra and RMS parameters were less representative for these analysis. CONCLUSION: The methodology allowed to determine the effect of the bleaching procedure and to estimate quantitatively the gloss parameter.
    IADR General Session 2009; 04/2009