RESUMEN
OBJECTIVES: To evaluate the effect of preheating glass-ionomer cement (GIC) restorative materials on stabilization time (ST) of their metal carboxylate bonds and on microhardness. METHODS AND MATERIALS: Two conventional high-viscosity GICs, Ketac Universal (3M ESPE) and Equia Forte (GC), were evaluated. The thermographic camera was used to measure the temperature inside the glass-ionomer cement capsules before and after heating. The preheating of capsules was performed at 54°C for 30 seconds in a commercial device. Characterization of ST in the GICs was determined by Fourier Transform Infrared (FTIR) spectroscopy. For this, 10 samples of each material were prepared, five in the non-preheated group (control) and five with preheating. FTIR spectra were obtained 10 minutes after mixing (control group) or after heating and then every 10 minutes for 120 minutes. For the microhardness test, 20 cylindrical specimens (3 mm height x 6 mm diameter) were prepared for each material (10 preheated, 10 control). The microhardness was determined at three time intervals: 10 minutes after mixing, after the ST as detected through the FTIR part of the study, and after one week. Knoop microhardness was assessed using a diamond indenter with a 25 g load and 15 seconds dwell time. RESULTS: Ketac Universal showed an increase in temperatures of 15.7°C for powder and 3.6°C for liquid, while Equia Forte showed 16.4°C for powder and 8.5°C for liquid. FTIR spectra indicated that preheating reduced the ST for Equia Forte but increased it for Ketac Universal. Preheating increased the initial microhardness (T1) of Equia Forte. With maturation over one week, it was observed that preheating significantly improved the microhardness of both materials compared with the control specimens. CONCLUSION: Preheating influenced the ST and the microhardness of Ketac Universal and Equia Forte. The ST and microhardness of Ketac Universal increased after seven days, whereas Equia Forte showed a reduced ST and increased microhardness from the outset.
Asunto(s)
Cementos de Ionómero Vítreo , Ensayo de Materiales , TemperaturaRESUMEN
OBJECTIVES: This study evaluated effects of Bioglass 45S5 (BG) and Biosilicate (BS) remineralization on the chemical composition and bond strength of control dentin (CD) and bleached dentin (BD) surfaces. METHODS AND MATERIALS: Dentin bleaching treatment was performed using the walking bleaching technique with 0.01 g of sodium perborate and 0.5 mL of 3% hydrogen peroxide for 14 days. Remineralization treatment was carried out by rubbing a remineralization solution (0.015 g of BG or BS diluted in 1.35 mL of distilled water) on the etched dentin surface for 30 seconds. Micro-Raman spectroscopy (MRS) was used to quantitatively analyze the mineral matrix ratios of CD and BD (n=5) after remineralization treatment with BG and BS over 15 days of incubation in artificial saliva. The CD and BD discs (n=10) with and without remineralization treatment with BG and BS were restored using a two-step etch-and-rinse adhesive system (Optibond S, Kerr) and five layers of 1-mm-thick composite resin (Filtek Z250, 3M ESPE). The restored dentin discs were sectioned into nine bonded beams with cross-sectional areas of approximately 0.9 mm2 and tested for microtensile bond strength (µTBS). The dentin surface of one fractured beam per tooth was submitted to MRS to characterize the physicochemical composition (n=10) at the interface. The data were analyzed using one-way analysis of variance and the Tukey-Kramer post hoc test (p<0.005). RESULTS: MRS bioactive analyses revealed that both BG and BS promoted increased mineral matrix ratios in the CD and BD. Significantly higher µTBS values were found after CD treatment with BG (CD: 57 MPa±11; CD-BG: 78 MPa±15) and when BG and BS were applied to the BD (BD: 42 MPa±5; BD-BG: 71 MPa±14; BD-BS: 64 MPa±11) (p<0.005). The MRS analysis of the fractured dentin beam showed that the remineralization treatment significantly increased the dentin relative mineral concentration and promoted the appearance of new interface peaks, indicating a chemical interaction (p<0.005). CONCLUSION: Remineralization of BD is an effective therapy to restore damage caused by dentin bleaching and acid conditioning. This approach not only increases dentin mineral compounds but also improves dentin's ability to interact chemically with the adhesive system.
Asunto(s)
Recubrimiento Dental Adhesivo , Resinas Compuestas , Cementos Dentales , Dentina , Recubrimientos Dentinarios , Cinética , Ensayo de Materiales , Cementos de Resina , Resistencia a la TracciónRESUMEN
Tooth wear is a multifactorial condition of growing concern. In clinical practice, it is often a challenge for prevention and treatment since many etiological factors may be involved. This case report describes an esthetic rehabilitation of a young patient presenting tooth wear due to erosion. The etiological factor of this case was the patient sucking on lemons, an acidic fruit. The main complaint of the patient was the appearance of short maxillary incisors. The treatment involved orthodontic and restorative dentistry techniques. First of all, an orthodontic device was used to increase the vertical dimension of occlusion and create an adequate space for the direct restorations. The posterior teeth were restored with two direct composite resin techniques; the anterior teeth were then restored using a balanced occlusion. The seven-year follow-up of the case is presented. Replicas of the restorations were made and visualized under scanning electron microscopy up to the 12-month evaluation. In the clinical follow-up at seven years, maintenance of the results and restorations can be clearly seen.
Asunto(s)
Rehabilitación Bucal/métodos , Erosión de los Dientes/terapia , Citrus , Resinas Compuestas , Restauración Dental Permanente/métodos , Estética Dental , Humanos , Masculino , Microscopía Electrónica de Rastreo , Erosión de los Dientes/inducido químicamente , Dimensión Vertical , Adulto JovenRESUMEN
OBJECTIVES: To characterize the chemical interactions and analyze the interface of adhesive systems containing 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) and N-methacryloyl glycine (methacrylamide) functional monomers with the dentin in noncarious cervical lesions (NCCLs) compared with artificial defects (ADs). METHODS AND MATERIALS: Twenty human teeth with natural NCCLs on the buccal surface were used. Class V cavities, similar to NCCLs, were created on the lingual surface to serve as controls. Teeth were randomly allocated to two groups according to the functional monomer in the adhesive (N=10): G1, 10-MDP; and G2, methacrylamide. NCCLs and ADs were characterized by their mineral composition (MC) and degree of demineralization (DD) using micro-Raman spectroscopy, adhesive/dentin chemical interactions (CIs) were assessed with infrared photoacoustic spectroscopy, and interface morphology was evaluated with scanning electron and light microscopy. MC, CI, and DD data were submitted to Shapiro-Wilk and Student t-tests ( p<0.05). RESULTS: Compared with ADs, dentin in NCCLs was hypermineralized ( p<0.05). In G1, CI, and DD in the first 2 µm, and adhesive projections in NCCLs and ADs interfaces were similar. Additionally, a thin layer of dentin collagen was observed in ADs, while it was hardly present in NCCLs. In G2, although CI could not be identified, changes in the mineral components were observed. The DD in the ADs and NCCLs were statistically similar, while SEM showed a lack of adhesion at NCCLs interface. DD and collagen exposure in the ADs and NCCLs were more pronounced than in G1. CONCLUSIONS: Results suggest that the G1 adhesive could be applied directly on the superficial sclerotic layer in NCCLs. In contrast, previous cavity preparation should be conducted to improve the micromechanical interaction of G2 with the dentin.
Asunto(s)
Acrilamidas/uso terapéutico , Grabado Dental/métodos , Recubrimientos Dentinarios/uso terapéutico , Dentina/cirugía , Metacrilatos/uso terapéutico , Cuello del Diente/cirugía , Restauración Dental Permanente/métodos , Dentina/efectos de los fármacos , Dentina/metabolismo , Humanos , Técnicas In VitroRESUMEN
The purpose of this study was to evaluate the chemical bonds of a self-etch 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) adhesive to natural noncarious cervical lesions (NCCLs) and compare them with those occurring in sclerotic dentin in artificially prepared defects (APDs). Four human teeth with natural NCCLs on the buccal surface were selected. Artificial defects matching the natural lesions were prepared on the lingual surface of the same teeth serving as control. Micro-Raman (MR) spectroscopy was used to quantify mineral content in natural NCCLs and in APDs. Fourier transform infrared-photoacoustic spectroscopy (FTIR-PAS) readouts were taken before and after adhesive application to analyze the protein matrix/mineral (M:M) ratio and chemical interactions between 10-MDP adhesive and dentin. The MR and FTIR-PAS spectra collected from natural NCCLs demonstrated a larger area of the band (961 cm-1, PO4) and lower M:M ratio, respectively, characterizing a hypermineralized dentin, compared with APDs. FTIR-PAS demonstrated emergence of a peak (1179 cm-1, P=O) in spectra after adhesive treatment, demonstrating a more intense chemical interaction in natural NCCLs. The results demonstrated that chemical bonding of 10-MDP adhesive to natural NCCLs is more intense, due to the hypermineralized surface, and suggest that it is unnecessary to remove the hypermineralized layer with burs, as this may decrease the chemical bonding potential of 10-MDP.
Asunto(s)
Cementos Dentales/química , Dentina/química , Metacrilatos/química , Desgaste de los Dientes/terapia , Recubrimiento Dental Adhesivo , Humanos , Técnicas In Vitro , Espectroscopía de Resonancia Magnética , Ensayo de Materiales , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría Raman , Propiedades de SuperficieRESUMEN
This study's aim was to evaluate the degradation rate of hydrogen peroxide (H2O2) and to quantify its penetration in tooth structure, considering the residence time of bleaching products on the dental enamel. For this study, bovine teeth were randomly divided according to the bleaching product received: Opalescence Xtra Boost 38%, White Gold Office 35%, Whiteness HP Blue 35%, Whiteness HP Maxx 35%, and Lase Peroxide Sensy 35%. To analyze the degradation of H2O2, the titration of bleaching agents with potassium permanganate was used, while the penetration of H2O2 was measured via spectrophotometric analysis of the acetate buffer solution, collected from the artificial pulp chamber. The analyses were performed immediately as well as 15 minutes, 30 minutes, and 45 minutes after product application. The data of degradation rate of H2O2 were submitted to analysis of variance (ANOVA) and Tukey tests, while ANOVA and Fisher tests were used for the quantification of H2O2, at the 5% level. The results showed that all products significantly reduced the concentration of H2O2 activates at the end of 45 minutes. It was also verified that the penetration of H2O2 was enhanced by increasing the residence time of the product on the tooth surface. It was concluded that the bleaching gels retained substantial concentrations of H2O2 after 45 minutes of application, and penetration of H2O2 in the dental structure is time-dependent.
Asunto(s)
Esmalte Dental/metabolismo , Peróxido de Hidrógeno/farmacocinética , Blanqueadores Dentales/farmacocinética , Animales , Bovinos , Pulpa Dental/metabolismo , Combinación de Medicamentos , Peróxido de Hidrógeno/administración & dosificación , Peróxidos/farmacocinética , Polivinilos/farmacocinética , Espectrofotometría , Blanqueamiento de Dientes/métodos , Blanqueadores Dentales/administración & dosificación , Urea/análogos & derivados , Urea/farmacocinéticaRESUMEN
The aim of this study was to investigate the diffusion dynamics of 25% hydrogen peroxide (H2O2) through enamel-dentin layers and to correlate it with dentin's structural alterations. Micro-Raman Spectroscopy (MRS) and Fourier Transform Infrared Photoacoustic Spectroscopy (FTIR-PAS) were used to measure the spectra of specimens before and during the bleaching procedure. H2O2 was applied to the outer surface of human enamel specimens for 60 minutes. MRS measurements were performed on the inner surface of enamel or on the subsurface dentin. In addition, H2O2 diffusion dynamics from outer enamel to dentin, passing through the dentin-enamel junction (DEJ) was obtained with Raman transverse scans. FTIR-PAS spectra were collected on the outer dentin. MRS findings revealed that H2O2 (O-O stretching µ-Raman band) crossed enamel, had a more marked concentration at DEJ, and accumulated in dentin. FTIR-PAS analysis showed that H2O2 modified dentin's organic compounds, observed by the decrease in amides I, II, and III absorption band intensities. In conclusion, H2O2 penetration was demonstrated to be not merely a physical passage through enamel interprismatic spaces into the dentinal tubules. H2O2 diffusion dynamics presented a concentration gradient determined by the chemical affinity of the H2O2 with each specific dental tissue.
Asunto(s)
Esmalte Dental/metabolismo , Dentina/metabolismo , Peróxido de Hidrógeno/farmacocinética , Blanqueadores Dentales/farmacocinética , Adolescente , Adulto , Amidas/análisis , Fenómenos Bioquímicos , Carbono/química , Niño , Color , Esmalte Dental/efectos de los fármacos , Dentina/efectos de los fármacos , Dentina/ultraestructura , Difusión , Humanos , Hidrógeno/química , Peróxido de Hidrógeno/farmacología , Microespectrofotometría , Oxígeno/química , Técnicas Fotoacústicas , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría Raman , Factores de Tiempo , Blanqueadores Dentales/farmacología , Adulto JovenRESUMEN
PURPOSE: To evaluate the effectiveness of different brands of nail varnish alone or associated with petroleum jelly as surface protectors for glass ionomer cements by determining dye uptake spectrophotometrically. MATERIALS AND METHODS: Three hundred thirty six specimens, 3.0 mm in diameter and 1.0 mm thick, were made with Chelon-Fil (CF) and ChemFil II (CII) and divided into 14 groups for each material. Positive control (A) and negative control (B) specimens were not protected, while experimental specimens were protected with six brands of nail varnish used with and without petroleum jelly. The specimens were immersed in 0.05% methylene blue solution 10 minutes after mixing except for negative control specimens that were immersed in deionized water. RESULTS: Dye uptake (microgram dye/restoration) for CF was: A = 11.3 +/- 3.1; B = 0.0 +/- 0.0 with varnish groups ranging from 0.6 to 2.5 and for CII: A = 12.4 +/- 2.5; B = 0.0 +/- 0.0 with varnish groups ranging from 0.4 to 2.4. The data were analyzed by ANOVA. The dye uptake among the groups was not significantly different (P < 0.01), except for the control group (unprotected cements).
Asunto(s)
Silicatos de Aluminio/farmacología , Cosméticos/farmacología , Cementos de Ionómero Vítreo/farmacología , Pintura , Vaselina/farmacología , Análisis de Varianza , Restauración Dental Permanente , Interacciones Farmacológicas , Técnica de Dilución de Colorante/estadística & datos numéricos , Humanos , Modelos Lineales , Ensayo de Materiales/métodos , Ensayo de Materiales/estadística & datos numéricos , Uñas , Propiedades de SuperficieRESUMEN
Aiming to evaluate placement and replacement of dental restorations, a questionnaire has been elaborated and distributed in Clinics of the Operative Dentistry Department, Bauru Dental Scholl--USP, for the students to point out some information about the operatory procedures performed. The analysis of the results made possible the observation that of the 241 restorations achieved, 45.64% were made due to primary caries and 54.36% were replacement of deficient restorations. The reasons for replacement as well as the possible factors responsible for failure of tooth-colored and amalgam restorations are analyzed and discussed.
Asunto(s)
Caries Dental/etiología , Restauración Dental Permanente/efectos adversos , Resinas Compuestas , Amalgama Dental , Caries Dental/terapia , Filtración Dental , Cementos de Ionómero Vítreo , Humanos , Recurrencia , Reoperación , Cemento de SilicatoRESUMEN
Aiming to evaluate the position variations of the upper canines in individuals with congenital cleft of the lip and palate which interfere in the final result of a prosthesis, we have done an analysis and a measurement of this alterations in casts of 208 patients with complete unilateral cleft before the prosthetic treatment. We have verified in the vertical direction, the infra-version and in the horizontal direction, the mesiodistal deviation of its relation of normal occlusion and the distance in relation to the mid line. The results obtained have become evident a frequent anterolateral openbite in the cleft side, besides a common deviation of the upper mid line, due to the general position of the upper canines on the side side of the cleft to the mesial.