RESUMO
A combination of atomic absorption spectroscopy (AAS), Fourier transform infrared spectroscopy (FTIR), scanning electronic microscopy (SEM), and gas adsorption techniques was used to characterize the effect of 30 % hydrogen peroxide (HP) on enamel surface. To perform the analyses of AAS, 1 ml of 30 % HP was added to 30 mg of a bovine enamel powder sample (150-200 µm fractions) for times of 5, 20, 60, 90, and 120 min; then 5 ml of the solution was withdrawn after each time period to measure [Ca(2+)] ions. The remaining powder was recovered and analyzed by FTIR. For SEM and gas adsorption tests, 4 × 4 mm(2) enamel sectioned samples were polished and 30 % HP was applied on the surface for the same time periods. AAS data show that 30 % HP treatment mobilized calcium from the enamel at all times studied. FTIR spectra showed that the total amount of phosphate and carbonate mineral contents such as amide I decreased significantly. SEM revealed that randomly distributed areas throughout the smooth enamel surface treatment became rougher and more irregular. These alterations indicate that surface damage increases with increasing durations of HP treatment. Gas adsorption analysis proved that bleached enamel is a typically non-porous material with a small specific surface area which decreases slightly with the 30 % HP treatment. In sum, 30 % HP induced a significant alteration of the organic and mineral part of the enamel, leading to the release of calcium and a rougher, more irregular enamel surface on randomly distributed areas.
Assuntos
Esmalte Dentário/química , Esmalte Dentário/efeitos dos fármacos , Peróxido de Hidrogênio/química , Adsorção , Animais , Bovinos , Gases/química , Microscopia Eletrônica de Varredura , Espectrofotometria Atômica , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de SuperfícieRESUMO
PURPOSE: To compare the percentage of collagen exposed in dentin root thirds after two irrigation protocols with manual or rotary instrumentation using two methacrylate resin-based sealers. MATERIALS AND METHODS: Forty-eight single-root human teeth were prepared with manual (n = 24) or nickeltitanium ProFile rotary (n = 24) instrumentation, using 5% NaOCl between instruments and 5 ml 17% EDTA as final irrigant or 20% citric acid + 2% chlorhexidine (CHX) between instruments and as the final irrigant. RealSeal or EndoREZ were used as filling materials. One 1-mm slice per third was abraded and stained with Masson's trichrome method. Mean exposed collagen values were obtained in four areas from each section (at 60X magnification) and a complete factorial ANOVA was used to analyze the influence of the study variables. Non-parametric Mann-Whitney's test was used to compare groups. Differences with p < 0.05 were considered significant. RESULTS: A significantly higher percentage of collagen was exposed in all thirds with the use of the 20% citric acid + 2% CHX protocol with rotary vs manual instrumentation, but percent collagen exposed did not differ as a function of the filling material. After the 5% NaOCl + 17% EDTA protocol, the percentage of collagen exposed did not differ between rotary and manual instrumentation but was higher with the use of RealSeal. CONCLUSION: The highest percentage exposure of collagen was with 20% citric acid + 2% CHX using rotary instrumentation, regardless of the filling material.
Assuntos
Colágeno/ultraestrutura , Cavidade Pulpar/ultraestrutura , Dentina/ultraestrutura , Materiais Restauradores do Canal Radicular/uso terapêutico , Irrigantes do Canal Radicular/uso terapêutico , Preparo de Canal Radicular/instrumentação , Condicionamento Ácido do Dente , Compostos Azo , Clorexidina/uso terapêutico , Ácido Cítrico/uso terapêutico , Corantes , Resinas Compostas/uso terapêutico , Ligas Dentárias/química , Ácido Edético/uso terapêutico , Amarelo de Eosina-(YS) , Humanos , Cura Luminosa de Adesivos Dentários , Metacrilatos/uso terapêutico , Verde de Metila , Níquel/química , Hipoclorito de Sódio/uso terapêutico , Titânio/química , Ápice Dentário/ultraestruturaRESUMO
PURPOSE: To investigate regional shear bond strength to lateral walls of ceramic inlays in occlusal and occlusoproximal cavities using etch-and-rinse and self-adhesive resin cements and a glass-ionomer luting agent. MATERIALS AND METHODS: IPS e.max Press ceramic inlays were made in 50 Class I and 50 Class II standardized cavities in intact extracted human molars and divided into 5 luting agent subgroups (n = 10): Variolink II (VL); Multilink Sprint (MLS); Multilink Automix (MLA); RelyX Unicem (RLX), and Ketac Cem Aplicap (KC). Inlays were pre-etched with IPS Ceramic etching gel for 60s. After 48 h, two disks of ca 1.0 mm thickness, one of superficial and the other of deep dentin, were push-out tested in a universal testing machine at a crosshead speed of 1.0 mm/min. The mode of failure was determined under a stereomicroscope at 20X. Data were analyzed with one way ANOVA, and Scheffé's test was used for post-hoc comparisons (α = 0.05). RESULTS: There were no significant differences in shear bond strength between Class I and Class II cavities for the dual-curing system in light-curing mode (VL=MLS=RLX), except that RLX demonstrated greater bond strength to deep dentin in Class II cavities. Bond strength values were significantly higher on deep than on superficial dentin. KC showed the worst result. Failures were mixed (adhesive/cohesive) for the resin luting cements and solely adhesive (cement/ceramic) for the glass-ionomer luting agent. CONCLUSION: Dual-curing etch-and-rinse or self-etching self-adhesive resin luting cements achieved greater bond strength when light curing was applied, with no differences between Class I and Class II cavities but higher values for deep vs superficial dentin. The weakest adhesion was obtained with glass-ionomer luting agent in both cavity types.
Assuntos
Cimentação/métodos , Colagem Dentária , Preparo da Cavidade Dentária/classificação , Porcelana Dentária/química , Cimentos de Ionômeros de Vidro/química , Restaurações Intracoronárias , Cimentos de Resina/química , Condicionamento Ácido do Dente/métodos , Adesividade , Preparo da Cavidade Dentária/instrumentação , Esmalte Dentário/ultraestrutura , Análise do Estresse Dentário/instrumentação , Dentina/ultraestrutura , Humanos , Ácido Fluorídrico/química , Cura Luminosa de Adesivos Dentários , Óxido de Magnésio/química , Teste de Materiais , Cimento de Policarboxilato/química , Autocura de Resinas Dentárias , Resistência ao Cisalhamento , Estresse Mecânico , Propriedades de Superfície , Fatores de Tempo , Óxido de Zinco/químicaRESUMO
PURPOSE: To measure the demineralization capacity of 37% phosphoric acid on surface and subsurface bovine enamel after bleaching with hydrogen peroxide (H2O2). MATERIALS AND METHODS: Three equally-sized sections with 16 mm2 of exposed enamel surface were obtained from the enamel of 10 bovine incisors. One specimen sample from each crown was assigned to one of three groups (n = 10): group I, no bleaching agent; group II, bleached with 38% H202 for 20 min; or group III, 30% H202 for 60 min. After 24 h, the thickness of specimens was measured and they were immersed in 37% phosphoric acid solution, of which 5-ml aliquots were collected at 30 s and 60 s. Specimens were then ground to a depth of 25 µm and again immersed in 37% phosphoric acid solution. This procedure was repeated for enamel depths of 50 and 100 µm. Ca2+ concentrations in the phosphoric acid aliquots were measured by atomic absorption spectroscopy. RESULTS: No significant differences were found in the total amounts of extracted Ca2+ between bleached and unbleached specimens (F = 0.142; p = 0.869). The amount of Ca2+ extracted was similar among the four depth levels in the unbleached and in the 30% H202 bleached specimens. A significantly larger amount of Ca2+ was obtained at 25 µm depth (subsurface) from specimens treated with 38% H202. CONCLUSIONS: Pre-bleaching with 38% H202 significantly increased the decalcifying effect of phosphoric acid on subsurface enamel at a depth of 25 µm compared to 100 µm, whereas pre-bleaching with 30% H202 did not modify this effect at any level.
Assuntos
Condicionamento Ácido do Dente/métodos , Esmalte Dentário/efeitos dos fármacos , Ácidos Fosfóricos/farmacologia , Clareamento Dental/métodos , Desmineralização do Dente/induzido quimicamente , Animais , Cálcio/análise , Bovinos , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Peróxido de Hidrogênio/administração & dosagem , Espectrofotometria Atômica , Propriedades de Superfície , Clareadores Dentários/administração & dosagemRESUMO
OBJECTIVES: To determine the influence of different etching times (5, 15 or 30 s) on the morphology and micro-tensile bond strength (muTBS) of primary dentin. METHODS: For muTBS study, nine primary molars were randomly distributed in three experimental groups. Three Class I cavities per tooth were drilled and etched (37% orthophosphoric acid gel for 5, 15 or 30 s). Excite adhesive was applied and cavities restored with a resin composite (Tetric Ceram). Composite/dentin bars (ca. 1 mm2 section) were obtained from teeth and tested in tension until debonding. Means of muTBS results were compared with ANOVA and Student-Neuman-Keuls post hoc tests. Morphology: Three occlusal cavities were prepared in five primary molars. Each cavity was etched and restored as described for previous groups and teeth were sectioned mesio-distally. One half of each tooth was prepared for using under optical microscopy using Masson's trichromic dye technique and the other half was examined by SEM. RESULTS: muTBS mean (S.D.) results (in MPa) were 5 s etch: 6.20 (2.81), 15 s: 13.43 (5.91), 30 s: 13.04 (5.67). muTBS groups were Excite 5 s < Excite 15 s = Excite 30 s. Masson's trichromic technique stained the demineralized dentin layer red in all specimens. The mean (S.D.) thickness of the demineralized layers (in mu) were 5 s: 3.28 (1.23), 15 s: 3.83 (1.26), 30 s: 4.44 (1.70). There is a statistically significant linear relationship between time of application of etching and mean depth of demineralized layer. This relationship was established as depth (in mu) = 3.08 + 0.05 time (in s). SIGNIFICANCE: The minimum adequate etching time for primary dentin is 15s.
Assuntos
Condicionamento Ácido do Dente/métodos , Adesivos Dentinários , Dentina/fisiologia , Cimentos de Resina , Dente Decíduo/fisiologia , Análise de Variância , Resinas Compostas , Colagem Dentária , Análise do Estresse Dentário , Dentina/ultraestrutura , Permeabilidade da Dentina , Humanos , Metacrilatos , Dente Molar , Ácidos Fosfóricos , Resistência à Tração , Fatores de TempoRESUMO
This study tested the null hypothesis that the opacity of RealSeal SE (RSSE) sealer makes light-curing inefficient, while the degree of conversion (DC) is similar regardless of curing method. Fourteen uniradicular teeth were sectioned at 15 mm from the apex. Root canals were instrumented using the Reciproc file system, bulk-filled with RSSE, and divided randomly into two groups (dual-cure or self-cure). DC was determined by micro-Raman spectroscopy at 24 h, 48 h, and 1 week after filling, at 6, 9, and 12 mm from the coronal end. Contrast ratio (Yb/Yw) was used to determine the opacity of the material. Descriptive statistics and nonparametric tests were used, and significance was defined as a P value of less than 0.05. Opacity was almost total by the first section, at 6 mm. In dual-cure mode, DC values at 24 h were lower in the apical section (63.8%) than in the more coronal sections and were lower than in self-cured specimens (87.4%). Light-curing of the coronal end did not improve DC. These differences remained at 48 h and 1 week. Only a small (2%) but significant increase in DC was observed in evaluations at 24 h and 1 week. (J Oral Sci 58, 333-338, 2016).
Assuntos
Adesivos , Materiais Restauradores do Canal Radicular , Análise Espectral RamanRESUMO
This article presents the long-term follow-up of a female patient who suffered pulp exposure during removal of a large caries lesion from the mandibular right first molar. The clinical decision to perform direct pulp capping was made. The tooth was treated with 5% chlorhexidine, etched with 37% phosphoric acid, and then restored with Heliomolar composite after application of Gluma dentin adhesive. The patient was followed for more than 8 years.
Assuntos
Capeamento da Polpa Dentária/métodos , Adesivos Dentinários/uso terapêutico , Resinas Acrílicas , Adulto , Resinas Compostas , Cárie Dentária/terapia , Exposição da Polpa Dentária/etiologia , Exposição da Polpa Dentária/terapia , Restauração Dentária Permanente/métodos , Dentina Secundária/diagnóstico por imagem , Feminino , Seguimentos , Glutaral/uso terapêutico , Humanos , Dente Molar , Ácidos Polimetacrílicos/uso terapêutico , Poliuretanos , RadiografiaRESUMO
The aim of the study is to determine the influence of the type of bracket, on bond strength, microhardness and conversion degree (CD) of four resin orthodontic cements. Micro-tensile bond strength (µTBS) test between the bracket base and the cement was carried out on glass-hour-shaped specimens (n=20). Vickers Hardness Number (VHN) and micro-Raman spectra were recorded in situ under the bracket base. Weibull distribution, ANOVA and non-parametric test were applied for data analysis (p<0.05). The highest values of ή as well as the ß Weibull parameter were obtained for metallic brackets with Transbond™ plastic brackets with the self-curing cement showing the worst performance. The CD was from 80% to 62.5%.
Assuntos
Cimentos Dentários/química , Braquetes Ortodônticos , Resinas Sintéticas/química , Falha de Equipamento , Teste de Materiais , Microscopia Eletrônica de Varredura , Análise Espectral Raman/métodos , Estresse Mecânico , Propriedades de Superfície , Resistência à TraçãoRESUMO
This study analyses how both ambulatory care groups (ACGs) and physician characteristics explain the variability in health-service use among primary care patients in Spain. During the period 1996-1997, data derived from 52,152 patients and their 38 respective primary care physicians were collected. The response variables were as follows: number of visits; diagnostic tests requested; and referrals to a specialist. ACGs are an important variable that should be taken into account in order to explain health-service utilization. As for professionals, age and the post they hold are essential factors. Most of the unexplained variability is caused by patient characteristics.
Assuntos
Assistência Ambulatorial/classificação , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Padrões de Prática Médica/estatística & dados numéricos , Atenção Primária à Saúde/estatística & dados numéricos , Assistência Ambulatorial/estatística & dados numéricos , Coleta de Dados , Feminino , Pesquisa sobre Serviços de Saúde , Humanos , Masculino , Medicina , Modelos Organizacionais , Visita a Consultório Médico/estatística & dados numéricos , Encaminhamento e Consulta , Espanha , EspecializaçãoRESUMO
OBJECTIVES: To investigate the bond strength and seal ability produced by AH Plus/gutta-percha, EndoREZ and RealSeal systems to root canal dentin. MATERIAL AND METHODS: Sixty extracted single-root human teeth, instrumented manually to size 40, were divided into three groups (n=20) according to the sealer used; G1: AH Plus, G2: EndoREZ, and G3: RealSeal sealers. After filling using the lateral condensation technique, each sealer group was randomly divided into two subgroups according to the tests applied (n=10 for µPush-out test and n=10 for fluid filtration test). A fluid filtration method was used for quantitative evaluation of apical leakage. Four 1-mm-thick slices (cervical and medium level) were obtained from each root sample and a µPush-out test was performed. Failure modes were examined under microscopy at 40x, and a one-way ANOVA was applied to analyze the permeability. Non-parametrical statistics for related (Friedman's and Wilcoxon's rank tests) or unrelated samples (Kruskal-Wallis' and Mann-Whitney's tests) allowed for comparisons of µPush-out strength values among materials at the different levels. Statistical significance was accepted for p values <.05. RESULTS: There are no significant differences among fluid filtration of the three sealers. The sealer/core material does not significantly influence the µPush-out bond strength values (F=2.49; p=0.10), although statistically significant differences were detected with regard to root level (Chi2=23.93; p<0.001). AH Plus and RealSeal obtained higher bond strength to intraradicular dentin in the medium root slices. CONCLUSIONS: There are no significant differences between the permeability and global µPush-out bond strength to root canal dentin achieved by AH Plus/gutta-percha, EndoREZ and RealSeal systems.
Assuntos
Colagem Dentária/métodos , Infiltração Dentária , Cavidade Pulpar/efeitos dos fármacos , Dentina/efeitos dos fármacos , Materiais Restauradores do Canal Radicular/química , Resistência à Tração , Resinas Compostas/química , Força Compressiva , Resinas Epóxi/química , Guta-Percha/química , Humanos , Teste de Materiais , Reprodutibilidade dos Testes , Preparo de Canal Radicular/métodos , Estatísticas não Paramétricas , Propriedades de SuperfícieRESUMO
The aim of the study was to determine the interfacial morphology and bond strength of three current self-etching adhesives (SEAs) to primary dentin and to evaluate the effect of introducing an additional step of phosphoric acid etching. Three human primary molars were assigned to each adhesive group for testing microtensile bond strength (microTBS) and three for studying interface morphology. Groups were: group 1, Excite, a total-etch adhesive (control); group 2, Adhese (ASE); group 3, Adper-Prompt-L-Pop (APLP), and group 4: Xeno III (XE) SEAs; groups 5-7 received application of 37% phosphoric acid for 15 s before applying ASE, APLP, and XE, respectively. A class I cavity was performed in each molar to study the interface morphology. Two halves of each tooth were used for examination either by optical microscopy, using Masson's trichromic dye technique, or by scanning electron microscopy. For microTBS determination, composite/dentin bars (1 mm(2) section) were obtained from each tooth, and tested in tension until debonding. The microTBS was significantly lower in the APLP than in the rest of the groups. The performance of SEAs on primary dentin depends on the product. Inclusion of dentin pre-etching step did not significantly modify microTBS results. All SAEs achieved greater decalcification depth on etched versus nonetched dentin.
Assuntos
Ácidos/química , Dentina/química , Adesividade , Corrosão Dentária , Dentina/ultraestrutura , Humanos , Microscopia Eletrônica de Varredura , Estresse MecânicoRESUMO
OBJECTIVES: To investigate the bond strength and seal ability produced by AH Plus/gutta-percha, EndoREZ and RealSeal systems to root canal dentin. MATERIAL AND METHODS: Sixty extracted single-root human teeth, instrumented manually to size 40, were divided into three groups (n=20) according to the sealer used; G1: AH Plus, G2: EndoREZ, and G3: RealSeal sealers. After filling using the lateral condensation technique, each sealer group was randomly divided into two subgroups according to the tests applied (n=10 for µPush-out test and n=10 for fluid filtration test). A fluid filtration method was used for quantitative evaluation of apical leakage. Four 1-mm-thick slices (cervical and medium level) were obtained from each root sample and a µPush-out test was performed. Failure modes were examined under microscopy at 40x, and a one-way ANOVA was applied to analyze the permeability. Non-parametrical statistics for related (Friedman's and Wilcoxon's rank tests) or unrelated samples (Kruskal-Wallis' and Mann-Whitney's tests) allowed for comparisons of µPush-out strength values among materials at the different levels. Statistical significance was accepted for p values <.05. RESULTS: There are no significant differences among fluid filtration of the three sealers. The sealer/core material does not significantly influence the µPush-out bond strength values (F=2.49; p=0.10), although statistically significant differences were detected with regard to root level (Chi2=23.93; p<0.001). AH Plus and RealSeal obtained higher bond strength to intraradicular dentin in the ...