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1.
J Appl Oral Sci ; 28: e20190771, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32609187

RESUMO

OBJECTIVE: Titanium dioxide nanotubes are nanostructures that can accelerate the oxidation reaction of bleaching procedures and promote a more effective whitening effect. This study evaluated physicochemical properties of bleaching agents incorporated with titanium dioxide (TiO2) nanotubes, and the effects on tooth color change at different periods. METHODOLOGY: 40 premolars were treated according to the following groups (n=10): CP - 10% carbamide peroxide (1 hour daily/21 days); CPN - CP incorporated into TiO2; HP - 40% hydrogen peroxide (three 40-minute sessions/7 days apart); HPN - HP incorporated into TiO2. Color shade was evaluated at five different periods (baseline, after 7, 14 and 21 days of bleaching, and 7 days after end of treatment) according to Vita Classical, CIELab and CIEDE2000 scales. Mean particle size (P), polydispersity (PO) and zeta potential (ZP) were evaluated using dynamic light scattering. Data on the different variables were analyzed by mixed model tests for measures repeated in time (ZP e L*), generalized linear models for measures repeated in time (P, PO, Vita Classical and b*), and Friedman and Mann-Whitney tests (a* and color change/ΔE and ΔE00). RESULTS: CP and CPN presented higher P, higher PO and lower ZP than HP and HPN (p≤0.05). All groups showed a significant decrease in Vita Classical color scores after 7 days of bleaching (p<0.05), and HPN presented a greater significant reduction than the other groups. L* increased in TiO2 presence, in all groups, without any differences (p>0.05) in bleaching time. A significant reduction occurred in the a* and b* values for all the groups, and HPN presented lower a* and b* values (p<0.05) than CPN. ΔE was clinically noticeable after 7 days, in all groups, and all groups resulted in a perceptible color change according to ΔE00. CONCLUSION: TiO2 did not influence physicochemical properties of the bleaching agents. HPN presented more effective tooth bleaching than CPN.

2.
J Adhes Dent ; 22(3): 285-296, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32435769

RESUMO

PURPOSE: To investigate the long-term effect of 0.05% or 0.1% caffeic acid phenethyl ester (CAPE) on dentin matrix stability and hybrid layer stability, using an etch-and-rinse (Adper Scotchbond Multipurpose/ASB) or a self-etch adhesive (Clearfil SE Bond/CSE). MATERIALS AND METHODS: Dentin matrix specimens were assigned to five groups: 0.05% or 0.1% CAPE, green tea (GT), and the controls distilled water (DW) and dimethyl sulfoxide (DMSO). Following immersion of specimens for 1 h, modulus of elasticity (ME) and dentin mass change (MG) were determined at 3 post-treatment time points: immediately afterwards and at 3 and 6 months. Collagen solubilization (CS) was estimated by hydroxyproline (HYP) quantification. Resin-dentin interfaces with both adhesives were assessed with in situ zymography tests to evaluate gelatinolytic activity (GA). The dentin pretreatments were actively applied for 60 s. The sealing ability of aged resin-bonded slices was assessed by nanoleakage tests. RESULTS: GT increased immediate ME, which decreased significantly after 3 months (p < 0.0001). The CAPE groups did not differ from the control groups. GT provided a significant increase in dentin matrix mass after treatment (p < 0.0001). No significant differences regarding MG were observed for CAPE 0.1%, CAPE 0.05%, DW, and DMSO groups after 3 and 6 months. Cumulative HYP release revealed that CAPE groups and GT were statistically similar to DW and DMSO; the GT group exhibited statistically significantly less HYP release than did CAPE groups (p = 0.0073). Treatment with 0.05% or 0.1% CAPE presented lower GA when applied to ASB before acid conditioning (p < 0.05), but no differences were detected when the CAPE groups were applied to CSE. CAPE at 0.1% significantly reduced nanoleakage for CSE, and 0.05% CAPE with CSE presented levels of nanoleakage similar to those of the CSE control group. CONCLUSION: CAPE at 0.05% or 0.01% did not influence ME, MG, or CS, but reduced GA when applied to ASB before acid conditioning. CAPE at 0.1% with CSE promoted adhesive layer integrity.


Assuntos
Colagem Dentária , Adesivos Dentinários , Ácidos Cafeicos , Cimentos Dentários , Dentina , Teste de Materiais , Álcool Feniletílico/análogos & derivados , Resistência à Tração
3.
Dent Mater ; 36(3): e85-e92, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32019690

RESUMO

OBJECTIVES: The aim of this study was to determine the physico-mechanical properties of a high viscosity glass ionomer cement (GIC) reinforced with TiO2 nanotubes (TiO2-nt). METHODS: TiO2-nt was incorporated into the GIC powder components (Ketac Molar EasyMix™) in concentrations of 0% (control group), 3%, 5%, 7% by weight. Compressive strength (n = 10/group), three point bending for flexural strength (n = 18/group), microshear bond strength to dentin and failure mode (n = 20/group), and surface roughness and weight loss before and after brushing simulation (30,000 cycles) (n = 8/group) were evaluated. Data were submitted to Shapiro-Wilk, ANOVA, Tukey and Chi-square tests (α ≤ 0.05). RESULTS: Addition of 5% of TiO2-nt into GIC presented the highest values for compressive strength and differed from the control, 3% and 7% groups (p = 0.023). There were no significant differences in flexural strength (p = 0.107) and surface roughness before and after the dental brushing (p = 0.287) among the groups. GIC added with 5% TiO2-nt showed the lowest weight loss values (p = 0.01), whereas the control, 3% or 5% TiO2-nt groups presented similar microshear bond strength values (p ≥ 0.05). The 5% TiO2-nt group featured higher microshear bond strength than the 7% TiO2-nt group (p = 0.034). Cohesive in material was the most representative failure mode for all groups. SIGNIFICANCE: The incorporation of TiO2-nt did not affect GIC's adhesiveness to dentin, but improved its compressive strength at 5%. Furthermore, TiO2-nt decreased the percentage of weight loss after GIC's surface wear.


Assuntos
Colagem Dentária , Nanotubos , Cimentos de Ionômeros de Vidro , Teste de Materiais , Propriedades de Superfície , Titânio
4.
RGO (Porto Alegre) ; 68: e20200004, 2020. tab, graf
Artigo em Inglês | LILACS-Express | ID: biblio-1091883

RESUMO

ABSTRACT Objective The aim of this study was to evaluate the in situ hardness, compressive strength and resilience of soft lining materials used in total removable prostheses in different time intervals Methods total of 48 rectangular test specimens (10 x 3 x 2 mm) were fabricated of each of the polyvinylsiloxane-based soft liner (Mucopren Soft) and acrylic resin-based material (Trusoft), which were placed on total removable prostheses bases of 12 volunteers (n = 12). The hardness (Shore A), compressive strength (in MPa) and resilience (in Kgf/cm2) were evaluated in different time intervals: 0, 7, 30 and 60 days, at three different locations of the specimens surface. Results The two-way ANOVA and Tukey test showed that the polyvinylsiloxane-based soft liner presented higher hardness values (p = 0.0113) and higher compressive strength (p=0.0252) than the acrylic resin-based material at immediate and 7 days evaluations. The polyvinylsiloxane-based soft liner presented higher resilience values than the acrylic resin-based material at all times (p = 0.0133). Hardness and compressive strength were similar for both materials at 30 and 60 days evaluations. Conclusions For both materials,there was a tendency for an increase of hardness, compressive strength and resilience over time, influenced by the composition of the tissue conditioner. The polyvinylsiloxane-based soft liner presented higher hardness, compressive strength and resilience than the acrylic resin-based material, specially considering a long-term evaluation up to 60 days.


RESUMO Objetivo O objetivo deste estudo foi avaliar in situ a dureza, resistência à compressão e resiliência de materiais para reembasamento utilizadas em próteses totais removíveis em diferentes intervalos de tempo. Métodos Um total de 48 corpos de prova retangulares (10 x 3 x 2 mm) foram confeccionados de cada uma dos reembasadores a base de polivinilsiloxano (Mucopren Soft, Kettenbach GmbH & Co) e resina acrílica (Trusoft, Bosworth), os quais foram posicionados na base de próteses totais removíveis de 12 voluntários (n = 12). A dureza (Shore A), resistência à compressão (em MPa) e resiliência (em Kgf/cm2) foram avaliadas em diferentes intervalos de tempo: 0, 7, 30 e 60 dias, em três diferentes localizações da superfície do corpo de prova. Resultados A ANOVA a dois critérios e o teste de Tukey mostraram que o reembasador a base de polivinilsiloxano apresentou maiores valores de dureza (p = 0,0113) e maior resistência à compressão (p=0,0252) do que o a base de resina acrílica nas avaliações nos tempos imediato e 7 dias. O reembasador a base de polivinilsiloxano apresentou maior resiliência que o a base de resina acrílica em todos os tempos (p = 0,0133). Dureza e resistência à compressão foram semelhantes para ambos os materiais nos tempos 30 e 60 dias de avaliação. Conclusões Para ambos os materiais, houve tendência de aumento da dureza, resistência à compressão e resiliência com o passar do tempo, influenciado pela composição dos materiais de rembasamento tecidual. O reembasador a base de polivinilsiloxano apresentou maior dureza, resistência à compressão e resiliência que o a base de resina acrílica, considerando-se especialmente o tempo de avaliação de 60 dias.

5.
Oral Health Prev Dent ; 17(6): 579-584, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31508600

RESUMO

PURPOSE: This study investigated the role of desensitising-only and desensitising/whitening versions of arginine and calcium carbonate-containing (ACC) and calcium sodium phosphosilicate-containing (CSPS) toothpastes on surface loss and permeability of root dentine. MATERIALS AND METHODS: Slabs of human root dentine were embedded and exposed to citric acid solution to create a lesion resembling hypersensitive dentine. Sixty specimens were divided into six groups and exposed to slurries made with ACC (Colgate Sensitive Pro-Relief) and CSPS (Sensodyne Repair & Protect) toothpastes, in their desensitising or desensitising/whitening versions, an ordinary toothpaste (Crest Cavity Protection) or distilled water (DI). The other 60 specimens were brushed with either slurries or DI and assessed for surface loss. All specimens were analysed for dentine permeability. Data were subjected to analysis of variance (ANOVA) and Fisher's least statistically significant difference tests. RESULTS: ANOVA (p = 0.018) showed that in the group brushed with DI surface loss was lower than in the groups brushed with toothpastes, but there was no statistically significant difference among the ordinary, desensitising-only and desensitising/whitening toothpastes. Dentine permeability was not influenced by brushing (p = 0.125). Toothpastes affected dentine permeability (p = 0.004), with the groups submitted to desensitising-only and desensitising/whitening toothpastes presenting significantly lower permeability than those submitted to DI, but no difference existed between the group treated with the ordinary toothpaste and DI. CONCLUSION: In comparison to desensitising-only, desensitising/whitening toothpastes neither accounted for increased surface loss nor impaired tubule occlusion of root dentine.


Assuntos
Dessensibilizantes Dentinários , Sensibilidade da Dentina , Dentina , Humanos , Permeabilidade , Cremes Dentais
6.
Dental Press J Orthod ; 24(3): 71-78, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31390453

RESUMO

OBJECTIVE: The objective of the present study was to perform a histological evaluation of a titanium mini-implant for orthodontic anchorage. Shear strength and fracture patterns that occurred immediately, 30 and 60 days after insertion with or without N-2-butyl-cyanoacrylate adhesive were evaluated. METHODS: Ninety-six mini-implants (Arrow, Peclab, Brazil) were placed in the tibia of 9 male rabbits, with or without an adhesive (Vetbond™, 3M, USA). Histological evaluation was done by optical light microscope. Shear strength testing was performed, followed by fracture analysis with visual inspection. RESULTS: Close contact between the newly formed bone and the device was evidenced in the group without adhesive, whereas gaps in the group with adhesive were found. Tukey test showed similar values in both groups at the immediate time point (20.70 N without adhesive and 24.69 N with adhesive), and higher values for the non-adhesive group, after 30 and 60 days (43.98 N and 78.55 N, respectively). The values for the adhesive group were similar for the immediate time point (24.69 N), 30 days (18.23 N) and 60 days (31.98 N). The fractures were adhesive for both groups at the immediate time point. The fractures were cohesive in bone for the non-adhesive group after 30 and 60 days. CONCLUSIONS: The mini-implants showed close bone contact and required higher shear strength for removal at 30 and 60 days for the non-adhesive group. Further studies are needed to assess the proper way to remove the orthodontic anchorage without cohesive fractures in bone.


Assuntos
Implantes Dentários , Procedimentos de Ancoragem Ortodôntica , Animais , Brasil , Cianoacrilatos , Cimentos Dentários , Masculino , Teste de Materiais , Coelhos , Estresse Mecânico , Titânio
7.
Dent Mater ; 35(10): 1471-1478, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31405618

RESUMO

OBJECTIVE: This study investigated the effects of dentin pretreatment with 2.5% titanium tetrafluoride (TiF4) on nanomechanical properties, and the in situ gelatinolytic activity of the dentin-resin interface, for up to 6 months. METHODS: Twenty-four human teeth were prepared by exposing occlusal flat dentin surfaces, and were randomly assigned to experimental groups, according to application or non-application of a TiF4 pretreatment, and to the adhesive systems (Clearfil SE Bond or Scotchbond Universal). Resin composite (Filtek Supreme Ultra) was built up incrementally on the teeth in all the groups. Then, the specimens were sectioned and randomly selected for evaluation at 24h, 3 months and 6 months of storage time. The reduced modulus of elasticity (Er) and the nanohardness of the underlying dentin, as well as the hybrid layer and the adhesive layer were measured using a nanoindenter. Gelatinolytic activity at the dentin-resin interfaces was assessed by in situ zymography using quenched fluorescein-conjugated gelatin at 24h and 6 months. Statistical analyses were performed with ANOVA and Tukey's tests. RESULTS: There were no differences in Er and nanohardness values between adhesives systems and pretreatment (p=0.1250). In situ zymography showed significantly higher gelatinolytic activity after 6 months for all the experimental groups (p=0.0004), but no differences between the adhesive systems (p=0.7708) and the surface pretreatment (p=0.4877). SIGNIFICANCE: Dentin pretreatment with 2.5% TiF4 followed by self-etching adhesive systems did not influence nanomechanical properties or gelatinolytic activity of the adhesive-dentin interface layers, over time.


Assuntos
Colagem Dentária , Adesivos Dentinários , Resinas Compostas , Cimentos Dentários , Dentina , Fluoretos , Humanos , Teste de Materiais , Cimentos de Resina , Propriedades de Superfície , Resistência à Tração , Titânio
8.
Am J Dent ; 32(3): 124-132, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31295393

RESUMO

PURPOSE: To conduct a clinical evaluation of dental bleaching techniques using hydrogen peroxide (HP), regarding tooth sensitivity, gingival irritation, subject's perception of color change, and calcium (Ca) and phosphorous (P) concentrations in enamel. METHODS: 75 volunteers were distributed according to the bleaching technique (n=25): (a) at-home: 10%HP (Opalescence GO) for 15 days of continuous use (1 hour per day); (b) in-office: 40%HP (Opalescence Boost) in three clinical sessions (40 minutes each session); (c) combined: one initial session with 40%HP, and the rest with 10%HP for 15 days of continuous use. Clinical evaluations and Ca and P concentration collections were obtained before, during bleaching treatment, and 15 days after conclusion of treatment. The generalized linear models were used to evaluate the data for VITA Classical scale, CIELAB, tooth sensitivity, degree of acceptability of the technique, Ca and P concentrations and to determine the ΔE variables and color change perception. Gingival irritation was analyzed by Fisher's Exact test. The total frequencies for each time interval (regardless of bleaching technique) were compared at 50% by the chi-square test. RESULTS: The in-office technique presented the lowest tooth sensitivity, but all techniques caused an increase in sensitivity over time (P< 0.0001). All techniques resulted in lower Ca and P concentrations in enamel at each time point, compared with the baseline concentrations. Calcium concentrations did not differ significantly among the treatments (P= 0.9360). Phosphorus concentration at the 8th day was higher for the in-office technique group (P< 0.05). All the bleaching techniques were effective in altering color, with ΔE values higher than 3.3, without any significant differences (P= 0.3255). Higher occurrence of gingival irritation was observed for at-home and combined techniques. The combined technique seemed to promote a color change faster than the other techniques. CLINICAL SIGNIFICANCE: All the dental bleaching techniques proved equally effective in promoting tooth color change. These techniques may reduce calcium and phosphorous content in enamel. The at-home and the combined techniques may cause greater dental sensitivity than the in-office technique, and led to a higher prevalence of gingival irritation.


Assuntos
Peróxido de Hidrogênio , Clareadores Dentários , Clareamento Dental , Descoloração de Dente , Esmalte Dentário , Humanos , Peróxido de Hidrogênio/uso terapêutico , Minerais , Clareamento Dental/métodos , Clareadores Dentários/uso terapêutico , Descoloração de Dente/tratamento farmacológico , Resultado do Tratamento
9.
Dental press j. orthod. (Impr.) ; 24(3): 71-78, May-June 2019. tab, graf
Artigo em Inglês | LILACS-Express | ID: biblio-1011972

RESUMO

ABSTRACT Objective: The objective of the present study was to perform a histological evaluation of a titanium mini-implant for orthodontic anchorage. Shear strength and fracture patterns that occurred immediately, 30 and 60 days after insertion with or without N-2-butyl-cyanoacrylate adhesive were evaluated. Methods: Ninety-six mini-implants (Arrow, Peclab, Brazil) were placed in the tibia of 9 male rabbits, with or without an adhesive (Vetbond™, 3M, USA). Histological evaluation was done by optical light microscope. Shear strength testing was performed, followed by fracture analysis with visual inspection. Results: Close contact between the newly formed bone and the device was evidenced in the group without adhesive, whereas gaps in the group with adhesive were found. Tukey test showed similar values in both groups at the immediate time point (20.70 N without adhesive and 24.69 N with adhesive), and higher values for the non-adhesive group, after 30 and 60 days (43.98 N and 78.55 N, respectively). The values for the adhesive group were similar for the immediate time point (24.69 N), 30 days (18.23 N) and 60 days (31.98 N). The fractures were adhesive for both groups at the immediate time point. The fractures were cohesive in bone for the non-adhesive group after 30 and 60 days. Conclusions: The mini-implants showed close bone contact and required higher shear strength for removal at 30 and 60 days for the non-adhesive group. Further studies are needed to assess the proper way to remove the orthodontic anchorage without cohesive fractures in bone.


RESUMO Objetivos: este estudo teve como objetivo realizar uma avaliação histológica de um mini-implante para ancoragem em Ortodontia. Avaliou-se, também, a carga de cisalhamento e o padrão de fratura imediatamente e após 30 e 60 dias da sua inserção, com ou sem o uso do adesivo N-butil-2-cianoacrilato. Métodos: noventa e seis mini-implantes (Arrow, Peclab, Brasil) foram instalados na tíbia de nove coelhos machos, com ou sem adesivo (Vetbond™, 3M, EUA). A avaliação histológica foi realizada com uso de microscópico de luz óptica. Realizou-se o teste de resistência ao cisalhamento, seguido pela análise da fratura, por meio de inspeção visual. Resultados: um contato íntimo entre o novo osso formado e o dispositivo foi evidenciado no grupo sem adesivo, enquanto espaços foram encontrados no grupo com adesivo. O teste de Tukey mostrou valores semelhantes em ambos os grupos no tempo imediato (20,70 N sem adesivo e 24,69 N com adesivo), e valores maiores para o grupo sem adesivo após 30 e 60 dias (43,98 N e 78,55 N, respectivamente). Os valores para o grupo com adesivo foram semelhantes para os tempos imediato (24,69 N), 30 dias (18,23 N) e 60 dias (31,98 N). As fraturas foram adesivas para ambos os grupos, no tempo imediato. As fraturas foram coesivas no osso para os grupos sem adesivo, após 30 e 60 dias. Conclusões: os mini-implantes mostraram um contato íntimo com o osso e requereram alta carga de cisalhamento para sua remoção após 30 e 60 dias nos grupos sem adesivo. Estudos adicionais são necessários para avaliar um método para remoção do dispositivo ortodôntico sem fratura coesiva no osso.

10.
Dental Press J Orthod ; 24(2): 66-72, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-31116289

RESUMO

OBJECTIVE: This study investigated the effect of the condition of lubrication on the friction between brackets and NiTi archwires of different rounded cross-sections. METHODS: Brackets (Roth, GAC) were affixed to a device connected to a universal testing machine into which segments of archwire were placed (NiTi, Nitinol, GAC) with cross-sections of 0.012-in, 0.016-in and 0.020-in. Once the wire was in the bracket slot, the following lubricants were applied: human saliva (HS: positive control), distilled water (DI), mucin-based (MUC) or carboxymethylcellulose-based (CMC) artificial saliva. In the negative control group, no lubricant was used. The combination between the wire cross-sections and the lubrication condition generated 15 groups with 15 samples each. Data were submitted to two-way analysis of variance and Tukey's test. RESULTS: There was no significant interaction between the wire cross-section and the condition of lubrication (p= 0.901). Irrespective of whether lubricants were used or not, there was a significant increase in friction with an increase in the cross-section of the wire (p< 0.001). For any wire, the group tested in the presence of MUC was not different from that in which HS was applied. On the other hand, when the application of lubricants was suppressed, significantly higher friction values were observed. The CMC group and the DI group demonstrated intermediate behavior. CONCLUSIONS: Friction increased with the increase of the cross-section of the NiTi archwire, but regardless of the archwire, friction with MUC artificial saliva was similar to that of HS and lower than in dry conditions.


Assuntos
Braquetes Ortodônticos , Ligas Dentárias , Fricção , Humanos , Teste de Materiais , Desenho de Aparelho Ortodôntico , Fios Ortodônticos , Aço Inoxidável , Propriedades de Superfície , Titânio
11.
Am J Dent ; 32(2): 99-104, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31094145

RESUMO

PURPOSE: To evaluate the influence of the infrastructure design and type of ceramic coverage on residual stresses after occlusal loading of crowns with yttria-stabilized zirconium oxide (Y-TZP) infrastructure, analyzed by means of the finite element method. METHODS: 3D models of a mandibular first molar total crown were constructed with two different types of infrastructures: a coping with a uniform thickness of 0.3 mm, and an anatomic coping with a thickness ranging from 0.3 mm to 1.5 mm, depending on the external anatomy of the crown, and three types of ceramic coverages: feldspathic, leucite- and lithium disilicate-reinforced types. Fusion 360 software ( Autodesk) was used to simulate occlusal loading of 300 N in an area of 1 mm² on the internal slopes of the mesial vestibular cusps. RESULTS: Higher tensile stress values ( σ1 positive) were observed for the ceramics with anatomic copings (800.3 MPa for feldspathic; 800.1 MPa for leucite, and 799.0 MPa for lithium disilicate), in comparison with the groups of uniform coping (482.0 MPa for feldspathic, 480.0 MPa for leucite, and 479.4 MPa for lithium disilicate). Stress distribution in all the groups followed the same type of pattern, with stresses developing in the load application region and following in the direction of the facial-lingual regions of the coverage crowns. The main maximum peaks of tensile strength were located below the points of load application and on the internal surface of the crown in the distolingual direction. The magnitudes of tensile stress on the anatomic coping ceramics were higher than on the uniform coping ceramics; the different coverage ceramics used did not influence the stress distribution pattern. CLINICAL SIGNIFICANCE: Ceramics on copings with a uniform shape resulted in lower values of internal stress development, in comparison with the anatomic-shaped copings, irrespective of the coverage ceramic used.


Assuntos
Coroas , Porcelana Dentária , Cerâmica , Análise do Estresse Dentário , Estresse Mecânico , Resistência à Tração
12.
Braz Oral Res ; 33: e044, 2019 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31141037

RESUMO

The aim of this study was to evaluate soluble and insoluble fluoride concentrations in commercial varnishes, and their remineralization effect on artificial caries enamel lesions using surface and cross-sectional microhardness evaluations. Forty bovine enamel blocks were separated into four groups (n=10): control (no treatment), Enamelast (Ultradent Products), Duraphat (Colgate-Palmolive) and Clinpro White Varnish (3M ESPE). Surface enamel microhardness evaluations were obtained, artificial enamel caries lesions were developed by dynamic pH-cycling, and the varnishes were then applied every 6 days, after which the enamel blocks were submitted to dynamic remineralization by pH cycles. After removal of the varnishes, the enamel surfaces were reassessed for microhardness. The blocks were sectioned longitudinally, and cross-sectional microhardness measurements were performed at different surface depths (up to 300 µm depth). Polarized light microscopy images (PLMI) were made to analyze subsurface caries lesions. The fluoride concentration in whole (soluble and insoluble fluoride) and centrifuged (soluble fluoride) varnishes was determined using an extraction method with acetone. The data were analyzed to evaluate the surface microhardness, making adjustments for generalized linear models. There was a significant decrease in enamel surface microhardness after performing all the treatments (p<0.0001). Enamelast and Duraphat showed significantly higher enamel microhardness values than the control and the Clinpro groups (p = 0.0002). Microhardness loss percentage was significantly lower for Enamelast (p = 0.071; One-way ANOVA). PLMI showed that subsurface caries lesions were not remineralized with the varnish treatments. No significant differences in the in-depth microhardness levels (p = 0.7536; ANOVA) were observed among the treatments. Enamelast presented higher soluble and insoluble fluoride concentrations than the other varnishes (p < 0.0001; Kruskal-Wallis and Dunn tests). Enamelast and Duraphat varnishes promoted enamel surface remineralization, but no varnish remineralized the subsurface lesion body. Although insoluble and soluble fluoride concentration values did not correspond to those declared by the manufacturer, Enamelast presented higher fluoride concentration than the others.


Assuntos
Cariostáticos/química , Cárie Dentária/tratamento farmacológico , Esmalte Dentário/efeitos dos fármacos , Fluoretos Tópicos/química , Remineralização Dentária/métodos , Análise de Variância , Animais , Bovinos , Testes de Dureza , Teste de Materiais , Microscopia de Polarização , Valores de Referência , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Propriedades de Superfície/efeitos dos fármacos , Fatores de Tempo
13.
Dental press j. orthod. (Impr.) ; 24(2): 66-72, Mar.-Apr. 2019. tab, graf
Artigo em Inglês | LILACS-Express | ID: biblio-1001855

RESUMO

Abstract Objective: This study investigated the effect of the condition of lubrication on the friction between brackets and NiTi archwires of different rounded cross-sections. Methods: Brackets (Roth, GAC) were affixed to a device connected to a universal testing machine into which segments of archwire were placed (NiTi, Nitinol, GAC) with cross-sections of 0.012-in, 0.016-in and 0.020-in. Once the wire was in the bracket slot, the following lubricants were applied: human saliva (HS: positive control), distilled water (DI), mucin-based (MUC) or carboxymethylcellulose-based (CMC) artificial saliva. In the negative control group, no lubricant was used. The combination between the wire cross-sections and the lubrication condition generated 15 groups with 15 samples each. Data were submitted to two-way analysis of variance and Tukey's test. Results: There was no significant interaction between the wire cross-section and the condition of lubrication (p= 0.901). Irrespective of whether lubricants were used or not, there was a significant increase in friction with an increase in the cross-section of the wire (p< 0.001). For any wire, the group tested in the presence of MUC was not different from that in which HS was applied. On the other hand, when the application of lubricants was suppressed, significantly higher friction values were observed. The CMC group and the DI group demonstrated intermediate behavior. Conclusions: Friction increased with the increase of the cross-section of the NiTi archwire, but regardless of the archwire, friction with MUC artificial saliva was similar to that of HS and lower than in dry conditions.


Resumo Objetivo: este estudo investigou o efeito das condições de lubrificação no atrito entre braquetes e fios de NiTi de diferentes secções transversais. Métodos: os braquetes (Roth, GAC) foram fixados a um dispositivo conectado a uma máquina de ensaio universal, que recebeu segmentos de fio de NiTi (Nitinol, GAC) com secções de 0,012"; 0,016" ou 0,020". Após o fio ter sido instalado no slot do braquete, aplicou-se um dos seguintes lubrificantes: saliva humana (SH: controle positivo), água destilada (AD) ou saliva artificial à base de mucina (MUC) ou de carboximetilcelulose (CMC). No grupo controle negativo, nenhum lubrificante foi utilizado. As combinações entre as secções dos fios e as condições de lubrificação geraram 15 grupos, com 15 amostras cada. Os dados foram submetidos à análise de variância a dois critérios e ao teste de Tukey. Resultados: não houve interação significativa entre a secção do fio e a condição de lubrificação (p = 0,901). Independentemente de ter sido utilizado ou não lubrificante, observou-se elevação significativa do atrito com o aumento da secção transversal do fio (p < 0,001). Para qualquer um dos fios, o grupo testado na presença de MUC não diferiu daquele em que se aplicou SH. Por outro lado, quando suprimiu-se os lubrificantes, constatou-se atrito significativamente mais elevado. Os grupos CMC e AD demonstraram comportamento intermediário. Conclusões: o atrito se elevou com o aumento da secção transversal dos fios de NiTi, mas a despeito do fio, o atrito com a saliva à base de MUC foi similar àquele com a SH e menor do que sob condição a seco.

14.
Oral Health Prev Dent ; 17(1): 57-67, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30793123

RESUMO

PURPOSE: To apply titanium tetrafluoride (TiF4) in an aqueous solution or incorporated into the primer of a self-etching adhesive (Clearfil SE Bond) as dentin pre-treatment and evaluate its antimicrobial effect, determine the minimum bactericidal concentraion (MBC) against Streptococcus mutans and Lactobacillus casei and analyse its potential to inhibit the development of carious lesions at the restoration interface. MATERIALS AND METHODS: For MBC, an aqueous solution or primer with different concentrations (in %) of TiF4 were used (from 0.0 to 4.0). Also, 50 cavities were prepared at the enamel/dentin junction of third molars and received the following dentin pre-treatments (n = 10): Clearfil SE Bond (CL); aqueous solution of 2.5% TiF4 + CL (T2.5%); aqueous solution of 4% TiF4 + CL (T4%); 2.5% TiF4 incorporated into the primer (P2.5%); 4% TiF4 incorporated into the primer (P4%). Cavities were restored and submitted to pH cycling to create artificial caries lesions. Microhardness tests were performed after sectioning the restorations to assess the demineralisation at margins. RESULTS: ANOVA and Tukey's tests showed that TiF4 in aqueous solution presented MBC against S. mutans and L. casei of over 2.0%. TiF4 in the primer of a self-etching adhesive presented MBC of over 1% for L. casei. For enamel, CL showed no significant differences in microhardness between the depths. CONCLUSIONS: The aqueous solution had an antimicrobial effect against Streptococcus mutans and Lactobacillus casei of over 2.0%. Pretreatment with the aqueous solution or primer did not inhibit demineralisation at enamel or dentin restoration interfaces.


Assuntos
Anti-Infecciosos , Colagem Dentária , Resinas Compostas , Esmalte Dentário , Dentina , Adesivos Dentinários , Fluoretos , Teste de Materiais , Titânio
15.
J Mech Behav Biomed Mater ; 91: 398-405, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30669058

RESUMO

Hydrolytic and enzymatic degradation by matrix metalloproteinases (MMPs) reduces the durability of composite resin restorations on caries-affected dentin (CAD). The use of MMP inhibitors such as epigallocatechin-3-gallate (EGCG) could increase the longevity of the bond to dentin. This study aimed to evaluate the use of EGCG at different aqueous concentrations on the resin-dentin microtensile bond strength (µTBS), fracture pattern and nanoleakage (NL) in immediate (IM) time interval and after 12-months of water storage (1Y) when using a two-step etch-and-rinse adhesive system on CAD. Dentin surfaces of 40 human molars were submitted to a microbiological caries induction protocol and randomized into 5 groups (n = 8) (0.02% EGCG; 0.2% EGCG; 0.5% EGCG; 2% Chlorhexidine [CHX] and no treatment as Control Group - [NT]). After acid etching, the solutions were applied for 60 s followed by application of dental adhesive (Adper Single Bond 2, 3 M ESPE) to CAD surfaces. Subsequently, a resin composite (4 mm) block was built on the dentin. After 24 h, the teeth were sectioned into beam-shaped specimens (cross-sectional area of 1 mm2 and 8-mm high). Half of the specimens were tested in IM and the other half after 1Y. Two samples per tooth were submitted to SEM for NL evaluation. Data were statistically analyzed by two-way ANOVA and Tukey tests (α = 0.05). The results showed that use of EGCG and CHX did not affect µTBS in IM (p > 0.05). After 1Y, there was a reduction in µTBS for all experimental groups (p < 0.05). Adhesive fractures predominated in IM in all groups, except for 0.05% EGCG and NT. After 1Y, there was an increase in these adhesive fractures in all groups. For NL, all agents applied reduced NL in comparison with CT (p < 0.001). CHX showed lower NL (p < 0.001), followed by 0.02% and 0.5% EGCG. NT showed highest NL for both time intervals (p < 0.001). Thus, although the use of EGCG at different concentrations and CHX reduced the NL, they were unable to reduce degradation of µTBS to CAD over time.

16.
J Prosthodont ; 28(1): e59-e67, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28872728

RESUMO

PURPOSE: To evaluate shade stability, surface roughness, microhardness, and compressive strength of a glazed feldspathic ceramic subjected to bleaching and simulated brushing. MATERIALS AND METHODS: Eighty-eight glazed feldspathic ceramic specimens were made from microparticulate leucite and divided into eight groups (n = 10). The whitening products used were: Opalescence Trèswhite Supreme (Ultradent), Opalescence®\ PF 15% (Ultradent), and Oral-B 3D White Whitestrips. All substances for whitening were used for 4 hours/day for a period of 14 days; the control group was not bleached. Next, half of the specimens were individually brushed. Microhardness and surface roughness data were subjected to three-way ANOVA and Tukey test. The diametrical tensile strength data were subjected to two-way ANOVA. The shade change data were analyzed using Kruskal-Wallis, Mann-Whitney, and the Student-Newman-Keuls test. The significance level was set at 5%. RESULTS: Glazed feldspathic ceramic surface microhardness was significantly affected by bleaching agents (p = 0.007). Initially, glazed ceramic microhardness was significantly higher than that observed after contact with the bleaching agents, whether or not brushing was performed. The specimens submitted to bleaching in preloaded trays presented lower surface roughness values after brushing (p = 0.037). The surface roughness was significantly lower in the brushed specimens (p = 0.044). The diametrical tensile strength was not significantly affected by the application of bleaching agents (p = 0.563) or by brushing (p = 0.477). When the specimens were brushed, however, shade change was significantly influenced by the bleaching agent used (p = 0.041). CONCLUSIONS: Bleaching agents associated with brushing cycles can alter surface properties and shade stability of glazed feldspathic ceramics, though such findings may not reflect the performance of unglazed feldspathic ceramics.


Assuntos
Cerâmica , Materiais Dentários , Pigmentação em Prótese , Clareadores Dentários , Cerâmica/química , Força Compressiva , Materiais Dentários/química , Dureza , Propriedades de Superfície , Resistência à Tração , Clareamento Dental/efeitos adversos , Clareadores Dentários/farmacologia , Escovação Dentária/efeitos adversos
17.
J Prosthodont ; 28(2): 209-215, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28234412

RESUMO

PURPOSE: To evaluate the influence of different core-veneer thickness (CVT) ratios on fracture loads and failure modes of zirconia crowns with or without thermomechanical cycling (TC). MATERIALS AND METHODS: Forty yttrium-stabilized tetragonal zirconia polycrystalline (Y-TZP) cores were veneered with a pressable ceramic and divided into four groups (n = 10): group 1 - 1:3 CVT ratio (0.5-mm core, 1.5-mm veneer); group 2 - 1:1 CVT ratio (1.0-mm core, 1.0-mm veneer); groups 3 and 4 - identical to groups 1 and 2, respectively, except that they underwent TC (1,000,000 cycles with an 84-N load applied at a 4-Hz frequency, temperature cycling at 4°C, 37°C, and 55°C - 30 seconds each). Loads were applied axially to the central fossa of the crowns with a 1 mm/min crosshead speed at 200 N until failure. RESULTS: Two-way ANOVA showed that the crowns with a 1:3 CVT ratio had a lower mean fracture load than crowns with a 1:1 CVT ratio (group 1 = 1666.4 ± 466.4 N; group 2 = 2156.6 ± 472.3 N). TC had no effect on the fracture load for crowns with the same CVT ratio. The failures observed for the crowns in groups 1, 3, and 4 were fractures within the veneering ceramic, which exposed the core. The failure severity of fractures for group 2 was less extensive, characterized by chipping within the ceramic veneer. CONCLUSION: Crowns with a 1:1 CVT ratio had higher fracture load values and more conservative failures. TC had no effect on the fracture load of the ceramic crowns.


Assuntos
Coroas , Planejamento de Prótese Dentária , Falha de Restauração Dentária , Facetas Dentárias , Zircônio/química , Cerâmica/química , Materiais Dentários/química , Análise do Estresse Dentário , Teste de Materiais , Estresse Mecânico , Propriedades de Superfície , Ítrio/química
18.
Braz. oral res. (Online) ; 33: e044, 2019. tab, graf
Artigo em Inglês | LILACS-Express | ID: biblio-1001614

RESUMO

Abstract: The aim of this study was to evaluate soluble and insoluble fluoride concentrations in commercial varnishes, and their remineralization effect on artificial caries enamel lesions using surface and cross-sectional microhardness evaluations. Forty bovine enamel blocks were separated into four groups (n=10): control (no treatment), Enamelast (Ultradent Products), Duraphat (Colgate-Palmolive) and Clinpro White Varnish (3M ESPE). Surface enamel microhardness evaluations were obtained, artificial enamel caries lesions were developed by dynamic pH-cycling, and the varnishes were then applied every 6 days, after which the enamel blocks were submitted to dynamic remineralization by pH cycles. After removal of the varnishes, the enamel surfaces were reassessed for microhardness. The blocks were sectioned longitudinally, and cross-sectional microhardness measurements were performed at different surface depths (up to 300 μm depth). Polarized light microscopy images (PLMI) were made to analyze subsurface caries lesions. The fluoride concentration in whole (soluble and insoluble fluoride) and centrifuged (soluble fluoride) varnishes was determined using an extraction method with acetone. The data were analyzed to evaluate the surface microhardness, making adjustments for generalized linear models. There was a significant decrease in enamel surface microhardness after performing all the treatments (p<0.0001). Enamelast and Duraphat showed significantly higher enamel microhardness values than the control and the Clinpro groups (p = 0.0002). Microhardness loss percentage was significantly lower for Enamelast (p = 0.071; One-way ANOVA). PLMI showed that subsurface caries lesions were not remineralized with the varnish treatments. No significant differences in the in-depth microhardness levels (p = 0.7536; ANOVA) were observed among the treatments. Enamelast presented higher soluble and insoluble fluoride concentrations than the other varnishes (p < 0.0001; Kruskal-Wallis and Dunn tests). Enamelast and Duraphat varnishes promoted enamel surface remineralization, but no varnish remineralized the subsurface lesion body. Although insoluble and soluble fluoride concentration values did not correspond to those declared by the manufacturer, Enamelast presented higher fluoride concentration than the others.

19.
Arch Oral Biol ; 94: 16-26, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29929070

RESUMO

OBJECTIVE: Investigate the long-term effect of dentin pretreatment with 0.05 or 0.1% caffeic acid phenethyl ester (CAPE) on (1) bond strength of resin composite to dentin by a three-step etch-and-rinse (Adper Scotchbond Multipurpose/ ASB) or a two-step self-etch adhesive system (Clearfil SE Bond/ CSE), (2) their fracture mode, (3) the micromorphological features of the hybrid layer formed; and (4) the level of MMP-2 in dentin (after application, using a correlative immunoexpression/quantification approach). DESIGN: Composite resin blocks were fabricated on 48 third molars (n = 6), according to the type of adhesive and treatment (control, CAPE 0.05% and CAPE 0.1%). Slices were obtained for scanning electron microscopy (SEM) evaluation, and sticks were fabricated for microtensile tests (24 h and 1 year). Aliquots of dentin powder were distributed (n = 12) according to the treatment and the MMP-2 concentration was determined by ELISA. RESULTS: Tukey test showed that ASB groups presented higher BS in 24 h than CSE groups. ASB presented a reduction in BS values after 1-year. ASB and CSE presented no significant differences in BS after 1-year. CAPE had no effect on BS for both adhesive systems. The predominant failure mode for the ASB groups were adhesive; when 0.1% CAPE was applied there was a predominance of mixed fractures. Regarding the CSE group, 0.05% CAPE led to more adhesive failures, and the 0.1% concentration resulted in a higher number of cohesive failures in dentin. Higher MMP-2 concentrations were detected for the groups that did not undergo demineralization treatment, and the lowest values for the ASB groups treated with CAPE. SEM analysis showed no influence of pretreatment with CAPE. CONCLUSIONS: CAPE did not influence the BS of the adhesives tested, or the micromorphology of the hybrid layer, irrespective of concentration or storage time. CAPE affected the fracture pattern at 24 h, depending on the concentration and the adhesive system used. Immunoassay analysis showed that CAPE 0.1% reduced the MMP-2 concentration in the ASB adhesive without affecting bond strength to dentin.


Assuntos
Condicionamento Ácido do Dente/métodos , Ácidos Cafeicos/farmacologia , Colagem Dentária , Adesivos Dentinários/química , Dentina/efeitos dos fármacos , Metaloproteinase 2 da Matriz/efeitos dos fármacos , Álcool Feniletílico/análogos & derivados , Resistência à Tração , Análise de Variância , Resinas Compostas/química , Cimentos Dentários , Falha de Restauração Dentária , Dentina/ultraestrutura , Cimentos de Ionômeros de Vidro/química , Humanos , Técnicas In Vitro , Teste de Materiais , Microscopia Eletrônica de Varredura , Dente Serotino , Álcool Feniletílico/farmacologia , Cimentos de Resina , Estresse Mecânico , Propriedades de Superfície
20.
Pesqui. bras. odontopediatria clín. integr ; 18(1): 3866, 15/01/2018. ilus, graf, tab
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-965740

RESUMO

Objective: This randomized controlled crossover clinical trial monitored the kinetics of salivary pH over time following the consumption of sour gummy candy. Material and Methods: Twenty participants underwent saliva assessment for flow, pH and buffer capacity. Following a two-arm crossover layout, the participants chewed a piece of a sour and a piece of an ordinary (control) gummy candy for 20 seconds. Participants expectorated saliva at 18 time points: immediately after ingesting the candies; then after every 15 second interval, for up to 1 minute; 30 seconds up to 4 minutes; 60 seconds up to 10 minutes; and at 15 minutes. The pH of the collected samples was measured with a pH microelectrode. The data concerning the pH measurements of the whole saliva samples collected over time following chewing of sour and ordinary gummy candies underwent repeated-measures three-way analysis of variance (ANOVA) using a significance level of 5%. Results: Repeated-measures three-way analysis of variance demonstrated a significant interaction between the type of candy and time (p<0.001). Tukey's test revealed that with the consumption of sour gummy candy, the salivary pH showed an initial marked exponential drop and remained lower than that observed with the consumption of the ordinary version for up to 120 seconds. Conclusion: The consumption of sour gummy candy induces a major, transient fall in salivary pH, which may represent a risk factor for dental erosion.


Assuntos
Humanos , Saliva/metabolismo , Desgaste dos Dentes , Concentração de Íons de Hidrogênio , Brasil , Análise de Variância
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