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1.
J Appl Oral Sci ; 28: e20190499, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348441

RESUMO

Enzymatic degradation of the hybrid layer can be accelerated by the activation of dentin metalloproteinases (MMP) during the bonding procedure. MMP inhibitors may be used to contain this process. Objective To evaluate the degree of conversion (DC%), dentin bond strength (µTBS) (immediate and after 1 year of storage in water), and nanoleakage of an experimental (EXP) and a commercial (SB) adhesive system, containing different concentrations of the MMP inhibitor GM1489: 0, 1 µM, 5 µM and 10 µM. Methodology DC% was evaluated by FT-IR spectroscopy. Dentin bond strength was evaluated by µTBS test. Half of beams were submitted to the µTBS test after 24 h and the other half, after storage for 1 year. From each tooth and storage time, 2 beams were reserved for nanoleakage testing. Data were analyzed using ANOVA and Tukey's test to compare means (α=0.05). Results All adhesive systems maintained the µTBS after 1 year of storage. Groups with higher concentrations of inhibitor (5 µM and 10 µM) showed higher µTBS values than groups without inhibitor or with 1 µM. The nanoleakage values of all groups showed no increase after 1 year of storage and values were similar for SB and EXP groups, in both storage periods. The inhibitor did not affect the DC% of the EXP groups, but the SB5 and SB10 groups showed higher DC% values than those of SB0 and SB1. Conclusions The incorporation of GM1489 in the adhesive systems had no detrimental effect on DC%. The concentrations of 5 µM GM1489 for SB and 5 µM or 10 µM for EXP provided higher µTBS than groups without GM1489, in the evaluation after 1 year of storage; whereas the concentration of inhibitor did not affect adhesive systems nanoleakage.


Assuntos
Cimentos Dentários/química , Dentina/química , Inibidores de Metaloproteinases de Matriz/química , Metacrilatos/química , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Análise de Variância , Colagem Dentária/métodos , Corrosão Dentária/métodos , Infiltração Dentária , Dentina/efeitos dos fármacos , Humanos , Teste de Materiais , Valores de Referência , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier , Estatísticas não Paramétricas , Propriedades de Superfície , Resistência à Tração , Fatores de Tempo
2.
Artigo em Inglês | LILACS-Express | LILACS, BBO - Odontologia | ID: biblio-1091638

RESUMO

Abstract Objective: To evaluate the topography and microhardness of composite resin restorations submitted to different finishing and polishing systems before and after erosive challenge. Material and Methods: Thirty standardized cavities prepared in enamel-dentin blocks of bovine incisors were restored with Z350 composite resin, and randomly distributed into three groups (n=10) according to the finishing and polishing systems: G1 = Soflex 4 steps, G2 = Soflex Spiral 2 steps and G3 = PoGo (single step). The specimens were half protected with nail varnish and submitted to five immersions in Pepsi Twist®, for 10 minutes each, five times/day during six consecutive days. The initial and final challenge surface microhardness (SMHinitial and SMHfinal) of the composite resin was evaluated and the percentage of SMH loss (%SMHL) was calculated. After protection removal, the topographic change linear (Ra) and volumetric (Sa) roughness was evaluated in initial and final areas by using 3D non-contact optical profilometry and scanning electron microscopy (SEM). Data were analyzed by paired Student's t-test, Kruskal-Wallis test, and by ANOVA and Tukey's test. Results: There was significant intra-group %SMHL in composite resin (p<0.05). Differences among groups in %SMHL, Ra/Sa in resin composite were not observed (p>0.05). SEM images revealed structural changes between the initial and final surfaces for all groups. Conclusion: The three types of finishing and polishing systems had a similar influence on %SMHL, Ra and Sa in the nanofilled composite resin.


Assuntos
Animais , Bovinos , Erosão Dentária/etiologia , Resinas Compostas , Esmalte Dentário , Dentina , Incisivo , Microscopia Eletrônica de Varredura , Análise de Variância , Estatísticas não Paramétricas , Imersão
3.
Artigo em Inglês | LILACS-Express | BBO - Odontologia, LILACS | ID: biblio-1056874

RESUMO

Abstract Objective: To evaluate the topography and microhardness of composite resin restorations submitted to different finishing and polishing systems before and after erosive challenge. Material and Methods: Thirty standardized cavities prepared in enamel-dentin blocks of bovine incisors were restored with Z350 composite resin, and randomly distributed into three groups (n=10) according to the finishing and polishing systems: G1 = Soflex 4 steps, G2 = Soflex Spiral 2 steps and G3 = PoGo (single step). The specimens were half protected with nail varnish and submitted to five immersions in Pepsi Twist®, for 10 minutes each, five times/day during six consecutive days. The initial and final challenge surface microhardness (SMHinitial and SMHfinal) of the composite resin was evaluated and the percentage of SMH loss (%SMHL) was calculated. After protection removal, the topographic change linear (Ra) and volumetric (Sa) roughness was evaluated in initial and final areas by using 3D non-contact optical profilometry and scanning electron microscopy (SEM). Data were analyzed by paired Student's t-test, Kruskal-Wallis test, and by ANOVA and Tukey's test. Results: There was significant intra-group %SMHL in composite resin (p<0.05). Differences among groups in %SMHL, Ra/Sa in resin composite were not observed (p>0.05). SEM images revealed structural changes between the initial and final surfaces for all groups. Conclusion: The three types of finishing and polishing systems had a similar influence on %SMHL, Ra and Sa in the nanofilled composite resin.

4.
J. appl. oral sci ; 28: e20190499, 2020. tab, graf
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1101251

RESUMO

Abstract Enzymatic degradation of the hybrid layer can be accelerated by the activation of dentin metalloproteinases (MMP) during the bonding procedure. MMP inhibitors may be used to contain this process. Objective To evaluate the degree of conversion (DC%), dentin bond strength (µTBS) (immediate and after 1 year of storage in water), and nanoleakage of an experimental (EXP) and a commercial (SB) adhesive system, containing different concentrations of the MMP inhibitor GM1489: 0, 1 µM, 5 µM and 10 µM. Methodology DC% was evaluated by FT-IR spectroscopy. Dentin bond strength was evaluated by µTBS test. Half of beams were submitted to the µTBS test after 24 h and the other half, after storage for 1 year. From each tooth and storage time, 2 beams were reserved for nanoleakage testing. Data were analyzed using ANOVA and Tukey's test to compare means (α=0.05). Results All adhesive systems maintained the µTBS after 1 year of storage. Groups with higher concentrations of inhibitor (5 µM and 10 µM) showed higher µTBS values than groups without inhibitor or with 1 µM. The nanoleakage values of all groups showed no increase after 1 year of storage and values were similar for SB and EXP groups, in both storage periods. The inhibitor did not affect the DC% of the EXP groups, but the SB5 and SB10 groups showed higher DC% values than those of SB0 and SB1. Conclusions The incorporation of GM1489 in the adhesive systems had no detrimental effect on DC%. The concentrations of 5 µM GM1489 for SB and 5 µM or 10 µM for EXP provided higher μTBS than groups without GM1489, in the evaluation after 1 year of storage; whereas the concentration of inhibitor did not affect adhesive systems nanoleakage.


Assuntos
Humanos , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Cimentos Dentários/química , Dentina/química , Inibidores de Metaloproteinases de Matriz/química , Metacrilatos/química , Valores de Referência , Propriedades de Superfície , Resistência à Tração , Fatores de Tempo , Teste de Materiais , Reprodutibilidade dos Testes , Análise de Variância , Colagem Dentária/métodos , Espectroscopia de Infravermelho com Transformada de Fourier , Estatísticas não Paramétricas , Infiltração Dentária , Dentina/efeitos dos fármacos , Corrosão Dentária/métodos
5.
J Adhes Dent ; 20(4): 335-340, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30206576

RESUMO

PURPOSE: To analyze the effect of a warm-air stream for solvent evaporation on the temperature rise in the pulp chamber during dentin hybridization. MATERIALS AND METHODS: Dentin disks with thicknesses of 0.5, 1.0 and 1.5 mm were obtained from extracted human molars. A model tooth was set up with the dentin disks between a molar with an exposed pulp chamber and a crown with an occlusal preparation. A K-type thermocouple connected to a digital thermometer was placed in the molar root until it entered the pulp chamber and made contact with the dentin disks. After 10 s of adhesive application, solvent evaporation was performed for 10, 20, 30, and 40 s and the increase in temperature was monitored for 200 s after the warm-air stream began. RESULTS: The temperature increase was significantly influenced by the thickness of the dentin disks (0.5 mm = 1.0 mm > 1.5 mm). With respect to the duration of the warm-air stream, the temperature increase was as follows: 10 s < 20 s < 30 s < 40 s (p < 0.05). The highest temperature was found after 40 s with dentin disks that were 0.5 mm (16.6°C) and 1.0 mm (15.8°C) thick, whereas the lowest temperature increase occurred after 10 s with a dentin disk that was 1.5 mm thick (4.1°C) (p < 0.05). CONCLUSION: The temperature in the pulp chamber was strongly influenced by the dentin thickness and the duration of the warm-air stream. Thinner dentin and a longer duration of the warm-air stream both lead to a greater temperature increase in the pulp chamber.


Assuntos
Adesivos Dentinários , Dentina , Cavidade Pulpar , Humanos , Solventes , Temperatura
6.
J Appl Oral Sci ; 26: e20170270, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29742262

RESUMO

Although resin composites are widely used in the clinical practice, the development of recurrent caries at composite-tooth interface still remains as one of the principal shortcomings to be overcome in this field. Objectives To evaluate the activity against S. mutans biofilm of model resin composites incorporating different concentrations of ZnO-nanoparticles (ZnO-NP) and characterize their physicochemical properties. Materials and Methods Different concentrations of ZnO-NP (wt.%): E1=0, E2=0.5, E3=1, E4=2, E5=5 and E6=10 were incorporated into a model resin composite consisting of Bis-GMA-TEGDMA and barium borosilicate particles. The activity against S. mutans biofilm was evaluated by metabolic activity and lactic acid production. The following physicochemical properties were characterized: degree of conversion (DC%), flexural strength (FS), elastic modulus (EM), hardness (KHN), water sorption (Wsp), water solubility (Wsl) and translucency (TP). Results E3, E4, E5 and E6 decreased the biofilm metabolic activity and E5 and E6 decreased the lactic acid production (p<0.05). E6 presented the lowest DC% (p<0.05). No significant difference in FS and EM was found for all resin composites (p>0.05). E5 and E6 presented the lowest values of KHN (p<0.05). E6 presented a higher Wsp than E1 (p<0.05) and the highest Wsl (p<0.05). The translucency significantly decreased as the ZnO- NP concentration increased (p<0.05). Conclusions The incorporation of 2 - 5 wt.% of ZnO-NP could endow antibacterial activity to resin composites, without jeopardizing their physicochemical properties.


Assuntos
Resinas Compostas/química , Resinas Compostas/farmacologia , Nanopartículas/química , Streptococcus mutans/efeitos dos fármacos , Óxido de Zinco/química , Óxido de Zinco/farmacologia , Análise de Variância , Compostos de Bário/química , Compostos de Bário/farmacologia , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Bis-Fenol A-Glicidil Metacrilato/química , Bis-Fenol A-Glicidil Metacrilato/farmacologia , Módulo de Elasticidade , Testes de Dureza , Modelos Lineares , Teste de Materiais , Microscopia Eletrônica de Varredura , Maleabilidade , Polietilenoglicóis/química , Polietilenoglicóis/farmacologia , Ácidos Polimetacrílicos/química , Ácidos Polimetacrílicos/farmacologia , Valores de Referência , Reprodutibilidade dos Testes , Silicatos/química , Silicatos/farmacologia , Solubilidade , Streptococcus mutans/crescimento & desenvolvimento , Propriedades de Superfície , Água/química
7.
J Appl Oral Sci ; 26: e20160460, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-29412362

RESUMO

Besides the effects on the health of individuals, cigarette smoking can also interfere with the appearance of their teeth. To evaluate the effect of cigarette smoking-toothbrushing-cycling (CSTC) with whitening toothpastes on the roughness and optical behavior of bovine enamel for eight weeks. Thirty bovine dentin/enamel discs, 8.0 mm in diameter and 2.0 mm thick, were randomly divided into three groups according to the toothpastes: whitening (Colgate Luminous White - CW and Oral B 3D White - OW), and a non-whitening (Colgate - C). The roughness, color (CIE L*a*b* system), translucency and gloss were measured before and after the specimens were submitted to CSTC. The topography of the specimens was analyzed by scanning electron microscopy. During the first week, the specimens were daily subjected to the consumption of 20 cigarettes and brushed (40 strokes/100 g) with the toothpastes' slurries. Thereafter, the CSTC was weekly applied in an accumulated model (140 cigarettes/280 strokes) for seven weeks. The data were submitted to two-way ANOVA, Tukey's HSD test, and paired-t test (α=0.05). The three toothpastes produced significant changes in roughness, color, translucency and gloss (p<0.05). After eight weeks, the roughness and the gloss produced by the three toothpastes were similar (p>0.05), while OW produced the lowest color change and the translucency of C was lower than that of CW (p<0.05). The three toothpastes produced a significant decrease in L* values and a significant increase in a* values after eight weeks (p<0.05). No significant difference in the b* coordinate was found for OW (p=0.13) There were topographic changes in the enamel surfaces. The whitening toothpastes increased the roughness, changed the topography and were not able to maintain the optical stability of enamel exposed over eight weeks.


Assuntos
Esmalte Dentário/química , Esmalte Dentário/efeitos dos fármacos , Dentifrícios/química , Fumar/efeitos adversos , Clareadores Dentários/química , Clareamento Dental/métodos , Cremes Dentais/química , Animais , Bovinos , Cor , Teste de Materiais , Microscopia Eletrônica de Varredura , Distribuição Aleatória , Reprodutibilidade dos Testes , Propriedades de Superfície/efeitos dos fármacos , Fatores de Tempo , Escovação Dentária/métodos
8.
J Adhes Dent ; 20(1): 57-64, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29457156

RESUMO

PURPOSE: To investigate the effect of Ca(OH)2 concentration on pH neutralization, degree of conversion (DC%), and bonding performance of experimental self-etch adhesives (SEAs). MATERIALS AND METHODS: Four different concentrations of Ca(OH)2 (0 wt%, 1 wt%, 2 wt%, and 4 wt%) were added to the bond of an experimental two-step SEA consisting of primer (10-MDP [30 wt%], TEG-DMA [30 wt%], ethanol [35 wt%], water [5 wt%], camphorquinone [0.5 wt%], and tertiary amine [0.5 wt%]) and bond (bis-GMA [50 wt%], TEG-DMA [30 wt%], HEMA [20 wt%], camphorquinone [0.5 wt%], and tertiary amine [0.5 wt%]) to form four groups: E0, E1, E2 and E4. pH neutralization was evaluated until it reached equilibrium, and DC% within the hybrid layer was analyzed by micro-Raman spectroscopy. Human molars were wet ground until the occlusal dentin was exposed, SEAs were applied, and composite buildups were constructed. After storage in distilled water at 37°C for 24 h, the teeth were cut into composite-dentin beams. Microtensile bond strength (µTBS) was evaluated after 24 h of water storage at 37°C. Nanoleakage was evaluated by SEM. Data were analyzed using ANOVA and Tukey's HSD test (a = 0.05). RESULTS: All the SEAs reached pH equilibrium after thirteen days, with E1 and E4 presenting the highest pH (p < 0.05). E0 and E1 presented lower DC% than did E2 and E4 (p < 0.05). All the SEAs showed statistically similar mTBS and nanoleakage (p > 0.05). CONCLUSION: The incorporation of Ca(OH)2 endowed the SEAs with pH-neutralization ability and improved their DC%, without interfering with the bond strength to dentin or nanoleakage extent.


Assuntos
Colagem Dentária , Adesivos Dentinários , Hidróxido de Cálcio , Resinas Compostas , Cimentos Dentários , Dentina , Humanos , Teste de Materiais , Metacrilatos , Cimentos de Resina , Resistência à Tração , Água
9.
J. appl. oral sci ; 26: e20170270, 2018. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-893712

RESUMO

Abstract Although resin composites are widely used in the clinical practice, the development of recurrent caries at composite-tooth interface still remains as one of the principal shortcomings to be overcome in this field. Objectives To evaluate the activity against S. mutans biofilm of model resin composites incorporating different concentrations of ZnO-nanoparticles (ZnO-NP) and characterize their physicochemical properties. Materials and Methods Different concentrations of ZnO-NP (wt.%): E1=0, E2=0.5, E3=1, E4=2, E5=5 and E6=10 were incorporated into a model resin composite consisting of Bis-GMA-TEGDMA and barium borosilicate particles. The activity against S. mutans biofilm was evaluated by metabolic activity and lactic acid production. The following physicochemical properties were characterized: degree of conversion (DC%), flexural strength (FS), elastic modulus (EM), hardness (KHN), water sorption (Wsp), water solubility (Wsl) and translucency (TP). Results E3, E4, E5 and E6 decreased the biofilm metabolic activity and E5 and E6 decreased the lactic acid production (p<0.05). E6 presented the lowest DC% (p<0.05). No significant difference in FS and EM was found for all resin composites (p>0.05). E5 and E6 presented the lowest values of KHN (p<0.05). E6 presented a higher Wsp than E1 (p<0.05) and the highest Wsl (p<0.05). The translucency significantly decreased as the ZnO- NP concentration increased (p<0.05). Conclusions The incorporation of 2 - 5 wt.% of ZnO-NP could endow antibacterial activity to resin composites, without jeopardizing their physicochemical properties.

10.
J. appl. oral sci ; 26: e20160460, 2018. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-893725

RESUMO

Abstract Besides the effects on the health of individuals, cigarette smoking can also interfere with the appearance of their teeth. Objective: To evaluate the effect of cigarette smoking-toothbrushing-cycling (CSTC) with whitening toothpastes on the roughness and optical behavior of bovine enamel for eight weeks. Material and Methods: Thirty bovine dentin/enamel discs, 8.0 mm in diameter and 2.0 mm thick, were randomly divided into three groups according to the toothpastes: whitening (Colgate Luminous White - CW and Oral B 3D White - OW), and a non-whitening (Colgate - C). The roughness, color (CIE L*a*b* system), translucency and gloss were measured before and after the specimens were submitted to CSTC. The topography of the specimens was analyzed by scanning electron microscopy. During the first week, the specimens were daily subjected to the consumption of 20 cigarettes and brushed (40 strokes/100 g) with the toothpastes' slurries. Thereafter, the CSTC was weekly applied in an accumulated model (140 cigarettes/280 strokes) for seven weeks. The data were submitted to two-way ANOVA, Tukey's HSD test, and paired-t test (α=0.05). Results: The three toothpastes produced significant changes in roughness, color, translucency and gloss (p<0.05). After eight weeks, the roughness and the gloss produced by the three toothpastes were similar (p>0.05), while OW produced the lowest color change and the translucency of C was lower than that of CW (p<0.05). The three toothpastes produced a significant decrease in L* values and a significant increase in a* values after eight weeks (p<0.05). No significant difference in the b* coordinate was found for OW (p=0.13) There were topographic changes in the enamel surfaces. Conclusions: The whitening toothpastes increased the roughness, changed the topography and were not able to maintain the optical stability of enamel exposed over eight weeks.

11.
Braz Oral Res ; 31: e68, 2017 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-28832715

RESUMO

The objective of this study was to compare coating dimensions and surface characteristics of two different esthetic covered nickel-titanium orthodontic rectangular archwires, as-received from the manufacturer and after oral exposure. The study was designed for comparative purposes. Both archwires, as-received from the manufacturer, were observed using a stereomicroscope to measure coating thickness and inner metallic dimensions. The wires were also exposed to oral environment in 11 orthodontic active patients for 21 days. After removing the samples, stereomicroscopy images were captured, coating loss was measured and its percentage was calculated. Three segments of each wire (one as-received and two after oral exposure) were observed using scanning electron microscopy for a qualitative analysis of the labial surface of the wires. The Lilliefors test and independent t-test were applied to verify normality of data and statistical differences between wires, respectively. The significance level adopted was 0.05. The results showed that the differences between the wires while comparing inner height and thickness were statistically significant (p < 0.0001). In average, the most recently launched wire presented a coating thickness twice that of the control wire, which was also a statistically significant difference. The coating loss percentage was also statistically different (p = 0.0346) when the latest launched wire (13.27%) was compared to the control (29.63%). In conclusion, the coating of the most recent wire was thicker and more uniform, whereas the control had a thinner coating on the edges. After oral exposure, both tested wires presented coating loss, but the most recently launched wire exhibited better results.


Assuntos
Materiais Revestidos Biocompatíveis/química , Níquel/química , Desenho de Aparelho Ortodôntico , Fios Ortodônticos , Titânio/química , Estética Dentária , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Boca/química , Braquetes Ortodônticos , Valores de Referência , Propriedades de Superfície , Fatores de Tempo
12.
Oral Health Prev Dent ; 15(3): 269-277, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28530007

RESUMO

PURPOSE: To evaluate the effect of CPP-ACPF paste and fluoride toothpastes on enamel subjected to erosion and erosion plus abrasion in vitro. MATERIALS AND METHODS: A total of 220 human enamel blocks were divided into eleven groups (n = 20): CPP-ACPF paste (MPP), potassium nitrate/sodium fluoride toothpaste (PE), sodium fluoride toothpaste (FD), fluoride-free toothpaste (SO) and control (erosion only with no paste or toothpastes; CO) according to the experimental design: erosion or erosion plus abrasion immediately after erosion (ERO+I-ABR) or 30 min after erosion (ERO+30min-ABR). For 5 days, the specimens were subjected to: (1) erosive challenge (EC) (cola drink, 4 x 5 min/day), topical application of the undiluted paste or diluted toothpastes (1:2 w/w) (4 x 1 min/ day) plus 1 h in artificial saliva (AS) between cycles and overnight; or (2) EC plus abrasion (4 x /60 s/day) performed with the diluted toothpastes (no MMP) plus 1 h in AS between cycles and overnight. Erosion depth was quantified through a 3D profilometer. Data were analysed using Kruskal-Wallis, Mann-Whitney and Wilcoxon tests (p = 0.05). RESULTS: CPP-ACPF paste and NaF toothpaste showed lowest enamel wear among groups and reduced tissue loss by 89% in erosion challenge. Abrasion led to higher enamel wear than erosion only (p = 0.030). ERO+30min-ABR had no protective effect when compared to ERO+I-ABR (p > 0.05). CONCLUSION: A high frequency of CPP-ACPF paste application (4x daily) is effective in reducing the effects of erosion. A waiting period before performing toothbrushing does not protect enamel against erosion regardless the composition of the toothpastes.


Assuntos
Caseínas/farmacologia , Esmalte Dentário/efeitos dos fármacos , Fluoretos/farmacologia , Abrasão Dentária/prevenção & controle , Cremes Dentais/farmacologia , Esmalte Dentário/ultraestrutura , Humanos , Imageamento Tridimensional , Técnicas In Vitro , Pomadas
13.
Braz Dent J ; 28(1): 97-104, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28301026

RESUMO

This study evaluated the effect of air-abrasion on t®m phase transformation, roughness, topography and the elemental composition of three Y-TZP (Yttria-stabilized tetragonal zirconia polycrystal) dental ceramics: two conventional (Lava Frame and IPS ZirCad) and one with high-translucency (Lava Plus). Plates obtained from sintered blocks of each ceramic were divided into four groups: AS (as-sintered); 30 (air-abrasion with 30 mm Si-coated Al2O3 particles); 50 (air-abrasion with 50 mm Al2O3 particles) and 150 (air-abrasion with 150 mm Al2O3 particles). After the treatments, the plates were submitted to X-ray diffractometry; 3-D profilometry and SEM/EDS. The AS surfaces were composed of Zr and t phases. All treatments produced t®m phase transformation in the ceramics. The diameter of air-abrasion particles influenced the roughness (150>50>30>AS) and the topography. SEM analysis showed that the three treatments produced groove-shaped microretentions on the ceramic surfaces, which increased with the diameter of air-abrasion particles. EDS showed a decrease in Zr content along with the emergence of O and Al elements after air-abrasion. Presence of Si was also detected on the plates air-abraded with 30 mm Si-coated Al2O3 particles. It was concluded that irrespective of the type and diameter of the particles, air-abrasion produced t®m phase transformation, increased the roughness and changed the elemental composition of the three Y-TZP dental ceramics. Lava Plus also behaved similarly to the conventional Y-TZP ceramics, indicating that this high translucency ceramic could be more suitable to build monolithic ceramic restorations in the aesthetic restorative dentistry field.


Assuntos
Cerâmica , Materiais Dentários , Ar , Teste de Materiais , Microscopia Eletrônica de Varredura , Espectrometria por Raios X , Difração de Raios X
14.
Braz. dent. j ; 28(1): 97-104, Jan.-Feb. 2017. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-839119

RESUMO

Abstract This study evaluated the effect of air-abrasion on t®m phase transformation, roughness, topography and the elemental composition of three Y-TZP (Yttria-stabilized tetragonal zirconia polycrystal) dental ceramics: two conventional (Lava Frame and IPS ZirCad) and one with high-translucency (Lava Plus). Plates obtained from sintered blocks of each ceramic were divided into four groups: AS (as-sintered); 30 (air-abrasion with 30 mm Si-coated Al2O3 particles); 50 (air-abrasion with 50 mm Al2O3 particles) and 150 (air-abrasion with 150 mm Al2O3 particles). After the treatments, the plates were submitted to X-ray diffractometry; 3-D profilometry and SEM/EDS. The AS surfaces were composed of Zr and t phases. All treatments produced t®m phase transformation in the ceramics. The diameter of air-abrasion particles influenced the roughness (150>50>30>AS) and the topography. SEM analysis showed that the three treatments produced groove-shaped microretentions on the ceramic surfaces, which increased with the diameter of air-abrasion particles. EDS showed a decrease in Zr content along with the emergence of O and Al elements after air-abrasion. Presence of Si was also detected on the plates air-abraded with 30 mm Si-coated Al2O3 particles. It was concluded that irrespective of the type and diameter of the particles, air-abrasion produced t®m phase transformation, increased the roughness and changed the elemental composition of the three Y-TZP dental ceramics. Lava Plus also behaved similarly to the conventional Y-TZP ceramics, indicating that this high translucency ceramic could be more suitable to build monolithic ceramic restorations in the aesthetic restorative dentistry field.


Resumo Este estudo avaliou o efeito da abrasão a ar na transformação de fase t®m, na rugosidade, topografia e composição elementar de três cerâmicas Y-TZP (Zircônia tetragonal policristalina estabilizada por ítrio): duas convencionais (Lava Frame e ZirCad) e uma de alta translucidez (Lava Plus). Placas obtidas de blocos sinterizados de cada cerâmica foram divididos em quatro grupos: AS (pré-sinterizado); 30 (jateamento com partículas de Al2O3 de 30 mm cobertas com Si); 50 (jateamento com partículas de Al2O3 de 50 mm) e 150 (jateamento com partículas de Al2O3 de 150 mm). Após os tratamentos, as placas foram submetidas à difratometria de Rx, perfilometria 3-D e microscopia eletrônica de varredura com espectroscopia de energia dispersiva de Rx (SEM/EDS). As superfícies pré-sinterizadas apresentaram predominantemente Zr e fase tetragonal. Todos os tratamentos superficiais produziram transformação t®m nas cerâmicas avaliadas. A topografia e a rugosidade foram influenciadas pelo diâmetro das partículas abrasivas (150>50>30>AS). A análise através de SEM mostrou que os três tratamentos produziram fendas retentivas nas superfícies das cerâmicas, por influência do tamanho das partículas. A análise através de EDS mostrou uma diminuição da concentração de Zr, paralela ao surgimento de O e Al, após o jateamento. No grupo tratado com partículas de Al2O3 de 30 mm cobertas com Si foi também observado um aumento de Si após o jateamento. Concluiu-se que, independente do tipo e do diâmetro das partículas, o jateamento produziu transformação t®m, aumentou a rugosidade e alterou a composição elementar das cerâmicas avaliadas. A Lava Plus apresentou comportamento semelhante às cerâmicas convencionais, indicando que esta cerâmica de alta translucidez pode ser mais adequada à confecção de restaurações monolíticas no campo da odontologia estética restauradora.


Assuntos
Ar
15.
Braz. oral res. (Online) ; 31: e68, 2017. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-952108

RESUMO

Abstract The objective of this study was to compare coating dimensions and surface characteristics of two different esthetic covered nickel-titanium orthodontic rectangular archwires, as-received from the manufacturer and after oral exposure. The study was designed for comparative purposes. Both archwires, as-received from the manufacturer, were observed using a stereomicroscope to measure coating thickness and inner metallic dimensions. The wires were also exposed to oral environment in 11 orthodontic active patients for 21 days. After removing the samples, stereomicroscopy images were captured, coating loss was measured and its percentage was calculated. Three segments of each wire (one as-received and two after oral exposure) were observed using scanning electron microscopy for a qualitative analysis of the labial surface of the wires. The Lilliefors test and independent t-test were applied to verify normality of data and statistical differences between wires, respectively. The significance level adopted was 0.05. The results showed that the differences between the wires while comparing inner height and thickness were statistically significant (p < 0.0001). In average, the most recently launched wire presented a coating thickness twice that of the control wire, which was also a statistically significant difference. The coating loss percentage was also statistically different (p = 0.0346) when the latest launched wire (13.27%) was compared to the control (29.63%). In conclusion, the coating of the most recent wire was thicker and more uniform, whereas the control had a thinner coating on the edges. After oral exposure, both tested wires presented coating loss, but the most recently launched wire exhibited better results.

16.
Braz Dent J ; 27(4): 446-51, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27652709

RESUMO

Studies have been showing a decrease of bond strength in dentin treated with sodium hypochlorite (NaOCl). The aim of this study was to evaluate the effect of non-thermal argon plasma on the bond strength of a self-etch adhesive system to dentin exposed to NaOCl. Thirty-two flat dentin surfaces of bovine incisors were immersed in 2.5% NaOCl for 30 min to simulate the irrigation step during endodontic treatment. The specimens were divided into four groups (n=8), according to the surface treatment: Control (without plasma treatment), AR15 (argon plasma for 15 s), AR30 (argon plasma for 30 s) and AR45 (argon plasma for 45 s). For microtensile bond strength test, 5 specimens were used per group. In each group, the specimens were hybridized with a self-etch adhesive system (Clearfil SE Bond) and resin composite buildups were constructed. After 48 h of water storage, specimens were sectioned into sticks (5 per tooth, 25 per group) and subjected to microtensile bond strength test (µTBS) until failure, evaluating failure mode. Three specimens per group were analyzed under FTIR spectroscopy to verify the chemical modifications produced in dentin. µTBS data were analyzed using ANOVA and Tamhane tests (p<0.05). AR30 showed the highest µTBS (20.86±9.0). AR15 (13.81±6.4) and AR45 (11.51±6.8) were statistically similar to control (13.67±8.1). FTIR spectroscopy showed that argon plasma treatment produced chemical modifications in dentin. In conclusion, non-thermal argon plasma treatment for 30 s produced chemical changes in dentin and improved the µTBs of Clearfil SE Bond to NaOCl-treated dentin.


Assuntos
Condicionamento Ácido do Dente/métodos , Argônio/química , Dentina/química , Gases em Plasma , Hipoclorito de Sódio/química , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier
17.
Braz. dent. j ; 27(4): 446-451, July-Aug. 2016. tab, graf
Artigo em Inglês | LILACS | ID: lil-794607

RESUMO

Abstract Studies have been showing a decrease of bond strength in dentin treated with sodium hypochlorite (NaOCl). The aim of this study was to evaluate the effect of non-thermal argon plasma on the bond strength of a self-etch adhesive system to dentin exposed to NaOCl. Thirty-two flat dentin surfaces of bovine incisors were immersed in 2.5% NaOCl for 30 min to simulate the irrigation step during endodontic treatment. The specimens were divided into four groups (n=8), according to the surface treatment: Control (without plasma treatment), AR15 (argon plasma for 15 s), AR30 (argon plasma for 30 s) and AR45 (argon plasma for 45 s). For microtensile bond strength test, 5 specimens were used per group. In each group, the specimens were hybridized with a self-etch adhesive system (Clearfil SE Bond) and resin composite buildups were constructed. After 48 h of water storage, specimens were sectioned into sticks (5 per tooth, 25 per group) and subjected to microtensile bond strength test (μTBS) until failure, evaluating failure mode. Three specimens per group were analyzed under FTIR spectroscopy to verify the chemical modifications produced in dentin. μTBS data were analyzed using ANOVA and Tamhane tests (p<0.05). AR30 showed the highest μTBS (20.86±9.0). AR15 (13.81±6.4) and AR45 (11.51±6.8) were statistically similar to control (13.67±8.1). FTIR spectroscopy showed that argon plasma treatment produced chemical modifications in dentin. In conclusion, non-thermal argon plasma treatment for 30 s produced chemical changes in dentin and improved the μTBs of Clearfil SE Bond to NaOCl-treated dentin.


Resumo Estudos vêm demonstrando uma diminuição na resistência adesiva em dentina tratada com hipoclorito de sódio (NaOCl). O objetivo desse estudo foi avaliar o efeito do plasma de argônio não-térmico na resistência de união de um sistema adesivo autocondicionante à dentina exposta ao NaOCl. Trinta e duas superfícies dentinárias lisas de incisivos bovinos foram imersas em NaOCl a 2,5% por 30 min para simular o passo de irrigação durante o tratamento endodôntico. Os espécimes foram divididos em 4 grupos (n=8), de acordo com o tratamento de superfície: Controle (sem tratamento de plasma), AR15 (plasma de argônio por 15 s), AR30 (plasma de argônio por 30 s) e AR45 (plasma de argônio por 45 s). Para teste de resistência de união por microtração, cinco espécimes foram utilizadas por grupo. Em cada grupo, os espécimes foram hibridizados com um sistema adesivo autocondicionante (Clearfil SE Bond, Kuraray) e blocos de resina composta foram construídos. Após 48 h de armazenamento em água, os espécimes foram seccionados em palitos (5 por dente - 25 por grupo) e submetidos ao teste de resistência de união por microtração (μTBS) até a fratura, avaliando o padrão de fratura. Três amostras por grupo foram analisadas sob espectroscopia por FTIR para verificar as modificações químicas produzidas pelos tratamentos na dentina. Os dados de microtração foram avaliados estatisticamente utilizando os testes de ANOVA e Tamhane (p<0,05). AR30 apresentou o maior μTBS (20,86±9,0). AR15 (13,81±6,4) e AR45 (11,51±6,8) foram estatisticamente semelhantes ao controle (13,67±8,1). A espectroscopia por FTIR mostrou que o tratamento de plasma produziu modificações químicas na dentina. Como conclusão, o tratamento de plasma de argônio não-térmico por 30 s produziu alterações químicas na dentina e melhorou o μTBS do Clearfil SE Bond à dentina tratada com NaOCl.


Assuntos
Condicionamento Ácido do Dente/métodos , Argônio/química , Dentina/química , Gases em Plasma , Hipoclorito de Sódio/química , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier
18.
Dent Mater J ; 35(2): 159-65, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27041003

RESUMO

This study evaluated the potential of a tri-functional monomer (trimethylolpropane trimethacrylate -TMPTMA) for inclusion in a dental composite organic matrix. Initially, four ternary matrixes with different concentrations (wt%) of bi-functional monomers [BisGMA (G), Bis-EMA (E) and TEGDMA (T)] were analyzed: GET523, GET532, EGT523 and EGT532 (the numbers (n) represent n×10 wt% of each monomer). The following properties were evaluated: degree of conversion, flexural strength, elastic modulus, hardness, absorption, solubility, diffusion coefficient of water and crosslink density. Based on the best overall results obtained for EGT532, all properties were re-evaluated in a matrix where TEGDMA (T) was replaced by a tri-functional monomer, TMPTMA (A)-EGA532. EGA532 presented the best results for flexural strength, hardness, absorption and crosslink density. EGT523, EGT532 and EGA532 presented the lowest diffusion coefficients of water. The overall results indicated that TMPTMA could be useful in formulating organic matrixes suitable for dental restorative composites.


Assuntos
Resinas Compostas , Módulo de Elasticidade , Dureza , Metacrilatos , Solubilidade
19.
Rev. odontol. UNESP (Online) ; 45(2): 121-126, mar.-abr. 2016. tab, graf
Artigo em Português | LILACS-Express | LILACS | ID: lil-780072

RESUMO

Resumo Introdução Os pinos de fibra de vidro são uma alternativa aos núcleos metálicos e apresentam vantagens, tais como: estética, módulo de elasticidade semelhante à dentina e cimentação imediata após o término do tratamento endodôntico. Ainda, apresentam a capacidade de aderir ao cimento resinoso e este, à dentina, por meio de técnicas adesivas. Objetivo Comparar a adesão de um cimento resinoso convencional e um autoadesivo a pinos de fibra de vidro, e os efeitos de diferentes tratamentos de superfície na resistência adesiva dos pinos. Material e método Trinta pinos foram divididos em três grupos: Controle: sem tratamento na superfície; Jateamento: jateamento com óxido de alumínio por 30 segundos, e Peróxido: imersão em peróxido de hidrogênio 24% por um minuto. Em seguida, corpos de prova foram obtidos a partir de cilindros de cimento resinoso contendo o pino de fibra posicionado no centro de seu longo eixo. Em cada grupo, cinco pinos foram associados ao adesivo Âmbar + cimento convencional AllCem Core e os outros cinco pinos, ao cimento autoadesivo RelyX U200. O conjunto pino/cimento foi segmentado e avaliado em relação à resistência de união (RU) por push-out. Os dados foram analisados estatisticamente pelos testes de ANOVA e Tukey (p<0,05). Resultado Os cimentos avaliados exibiram valores de RU semelhantes. Em relação aos tratamentos de superfície, os maiores valores de RU foram encontrados no grupo Jateamento. Conclusão O cimento convencional, AllCem Core, e o cimento autoadesivo, RelyX U200, mostraram valores de resistência de união semelhantes. Ainda, o jateamento com óxido de alumínio favoreceu a adesão dos pinos aos cimentos.


Abstract Introduction The fiberglass posts are an alternative to the metal cast, presenting some advantages, such as aesthetics, tensile modulus similar to dentin and can be placed in a single session, immediately after the endodontic treatment. It also has the ability to adhere to the resin cement and the last to dentin by means of bonding techniques. Objective To compare the adhesion of a conventional resin cement with a self-adhesive to fiberglass posts, and the effects of different surface treatments on adhesion of posts. Material and method Thirty fiber posts were divided into 3 groups: control: untreated surface; Blasting: blasting with aluminum oxide for 30 seconds and peroxide: immersion in 24% hydrogen peroxide for 1 minute. Then, the samples were obtained from resin cement cylinders containing the fiber post positioned in the center of its long axis. In each group 5 posts were associated with the adhesive Ambar+conventional cement Allcem Core and the other 5 posts with the self-adhesive cement RelyX U200. The post/cement sample was segment in discs and evaluated for bond strength (BS) by push-out test. Data were analyzed statistically by ANOVA and Tukey tests (p<0.05). Result The cements evaluated exhibited similar BS values. Regarding surface treatments, the highest BS values were found in blasting group. Conclusion Conventional cement, Allcem Core, and self-adhesive, RelyX U200, showed similar bond strength values. Also, blasting with aluminum oxide favored the adhesion of posts to cements.

20.
Braz Dent J ; 26(5): 497-502, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26647935

RESUMO

The aim of this study was to evaluate the microtensile bond strength of self-etch adhesive systems to dentin after storage in acids from oral biofilm. Three adhesive systems were used in the study: a two-step self-etch adhesive for use with a silorane-based resin composite (Filtek P90 adhesive system - P90), a two-step self-etch adhesive (Clearfil SE Bond - CSE) and a one-step self-etch adhesive (Adper Easy One - AEO). The bond strength of these products was evaluated by bonding resin composite (Filtek Z350 for CSE and AEO; and Filtek P90 for P90) to 90 bovine dentin tooth fragments, according to the manufacturer's instructions. After 24 h of water storage at 37 °C, the specimens were sectioned into beams (1 mm2) divided and stored in distilled water, lactic acid and propionic acid, for 7 and 30 days. After storage, the specimens were tested for microtensile bond strength. Data were analyzed by three-way ANOVA and Tukey´s test (α=0.05). CSE presented the highest microtensile bond strength after storage in distilled water for 7 and 30 days. The microtensile bond strength of all adhesive systems was lower after storage in lactic acid and propionic acid than after water storage. Significant difference was not found between storage times.


Assuntos
Ácidos/química , Biofilmes , Cimentos Dentários , Dentina , Condicionamento Ácido do Dente , Animais , Bovinos , Resistência à Tração
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