Enamel evaluation by scanning electron microscopy after debonding brackets and removal of adhesive remnants

The bonding of accessories in the dental crown during the orthodontic treatment creates microporosities, thus promoting micromechanical retention of the adhesive to the enamel structure. After debonding brackets, at the end of the active orthodontic treatment, a certain amount of adhesive remnants must be mechanically removed from the enamel. The objective of this study was to compare, by means of scanning electron microscopy, three different methods to remove the adhesive remnants after orthodontic bracket removal. An experimental analytical study was conducted on human premolar specimens, extracted within a year or less. The preparation of the enamel was carried out with the application of 35% phosphoric acid and Transbond XT Light Cure Adhesive Primer® adhesive. Edgwise Standart prescription brackets, slot .022 ?(Morelli Orthodontia) were glued to the enamel using Transbond XT® bonding resin. The brackets were placed on the center of the vestibular face of the clinical crown, and a 300-gram pressure was exerted against the surface of the enamel, measured with an orthodontic dynamometer. The brackets were debonded with adhesive removing pliers, and the samples were divided into groups, according to the protocol used for adhesive remnant removal: high-speed multi-laminated drill bit, low-speed multi-laminated drill bit, and low-speed glass fiber. After removal of the adhesive remnants, the samples went through scanning electron microscopy, obtaining electro micrographs with a magnification range of 150 X, 500 X, and 2,000 X. The tested method showed that the best effectiveness for the removal of the adhesive remnants after bracket debonding was the use of a tungsten carbide multi-laminated high speed, followed by the use of a tungsten carbide multi-laminated, low-rotation drill. The use of fiberglass drill alone has proved to be inefficient for clinical use, given the large amounts of adhesive remnants it leaves on the enamel. All methods evaluated in this study proved to be inefficient for total removal of adhesive remnants from the enamel

Eficácia de três condições de interpretação radiográfica em odontometria

OBJECTIVE: To compare the efficacy of three conditions of image interpretation for radiographic root measurements and calculating the intra-observer reproducibility of the measurements. MATERIAL AND METHODS: Thirty intra-operative periapical radiographs of maxillary central and lateral incisors were measured, in mm, from the tip of the file to the radiographic apex, using a caliper. Three separate measurements were made of the 30 radiographs. The three measurements for each tooth were averaged and the mean used for further calculations. After a 12-day period, the measurements were repeated. The three experimental viewing conditions used: 1) standard viewbox without masking of background light around the radiograph and without magnification (Visual); 2) standard viewbox with use of a magnifying lens of 2.5x and with background light masked (Magnification); and 3) viewer device that restricts room lighting and enlarges the image by a magnifying lens of 1.75x (Viewer). The mean and standard deviation of the measurements were calculated and used for descriptive analysis. Two-way analysis of variance (ANOVA) was used to evaluate intra-observer and inter-method agreement of the measurements. The measurement error was estimated by Dalhberg's formula. RESULTS: The ANOVA showed no significant differences between measurement sessions, viewing methods, or interaction between observation session and method (p>;0.05). The intra-observer measurement error was 0.02 mm for Visual and the Magnification methods and 0.01 mm for the Viewer. CONCLUSION: There does not seem to be any advantage in using viewbox masking or magnification for measuring the distance between the end of the endodontic file and the root apex in maxillary incisors.OBJETIVO: Comparar a eficácia de três condições de interpretação radiográfica em odontometria e avaliar a concordância intra-observador. MATERIAL E MÉTODO: Trinta radiografias periapicais de incisivos central e lateral superiores, de arquivos foram medidas, em mm, da extremidade da lima ao ápice radiográfico, com a utilização de um paquímetro digital. Foram feitas três medidas em cada radiografia e em seguida foi calculada a média. Após um período de 12 dias, as medidas foram repetidas. As três condições experimentais de interpretação radiográfica foram: negatoscópio sem máscara e sem magnificação (Visual); 2) negatoscópio com lente de aumento de 2,5 X e com máscara (Magnificação) e 3) bloqueador de luz e lente de aumento de 1,75 X (Bloqueador). As médias e os desvios-padrão das medidas foram calculados e realizada uma análise descritiva. Foi utilizada a análise de variância a dois critérios (ANOVA) para avaliar a concordância intra-observador e intramétodo. O erro das medidas foi calculado pela fórmula de Dalhberg. RESULTADOS: O teste ANOVA não mostrou diferenças significantes entre as duas sessões de observação, métodos de interpretação ou interação entre as sessões de interpretação e método (p>;0,05). A medida intra-observador foi 0,02 mm para os métodos Visual e Magnificação e 0,01 mm para o Bloqueador. CONCLUSÃO: Parece não haver qualquer vantagem realizar medidas da distância entre o ápice radicular e o extremo da lima endodôntica em dentes incisivos superiores utilizando máscara ou magnificação da imagem

Effect of two formulations of 10% sodium ascorbate on fracture resistance of endodontically treated tooth submitted to dental bleaching with hydrogen peroxide associated titanium dioxide nanoparticles

PURPOSE: This study evaluated the effect of 10% sodium ascorbate (10SA), in gel (10SAg) or aqueous solution (10SAs) formulations, on fracture resistance of endodontically treated tooth submitted to dental bleaching procedures with 15% hydrogen peroxide associated with titanium dioxide (15HP-TiO2) nanoparticles and photoactivated by LED-laser. MATERIAL AND METHODS: Forty maxillary premolars were endodontically-treated and embedded in acrylic resin up to the cement-enamel junction. The specimens were divided into four groups (n=10): G1 (negative control): no bleaching, coronal access restored with composite resin; G2 (positive control): three dental bleaching  sessions using 15HP-TiO2 and LED-laser photoactivation and restored with composite resin (positive control); G3 (10SAg): similar procedures to G2, but applied  10SA, in gel formulation, for 24 hours before restoration; G4 (10SAs): similar procedures to G3, but applied  10SA, in aqueous solution formulation.  The 15HP-TiO2 was applied on buccal and lingual surfaces of the crown tooth and inside the pulp chamber and photoactivated by LED-laser. Between each bleaching session, the teeth were maintained in artificial saliva, at 37oC, for 7 days. In sequence, the teeth were submitted to fracture resistance testing using an eletromechanical machine test. The data was analyzed using Kruskal Wallis test (p = 0.05) RESULTS: There are no differences significant among the groups in relation to fracture resistance of endodontically treated teeth (p>0.05). CONCLUSIONS: The use of 10% sodium ascorbate, in gel or aqueous solution formulations, did not interfered on the fracture resistance teeth after dental bleaching using 15HP-TiO2 and LED-laser photoactivation

Bond strength of adhesive resin cement with different adhesive systems

To assess the immediate bond strength of a dual-cure adhesive resin cement to the hybridized dentin with different bonding systems. Fifty-six healthy human molars were randomly divided into 7 groups (n=8). After 3 longitudinal sections, the central cuts were included in PVC matrix and were submitted to dentin hybridization according to the groups: G1 - etch & rinse system with 3-step (Apder™ Scotchbond™ Multi-Purpose, 3M ESPE), G2 - etch & rinse system with 3-step (Optibond™ FL, Kerr), G3 - etch & rinse system with 3-step (All-Bond 3®, Bisco), G4 - etch & rinse simplified system (Adper™ Single Bond 2, 3M ESPE), G5 - self-etching system with one step (Bond Force, Tokuyama), G6 - universal system in moist dentin (Single Bond Universal, 3M ESPE), G7 - universal system in dry dentin (Single Bond Universal, 3M ESPE). Then all groups received the cementing of a self-adhesive resin cement cylinder (Duo-link, Bisco) made from a polypropylene matrix. In the evaluation of bond strength, the samples were subjected to the microshear test and evaluated according to the fracture pattern by optical microscopy. The Kruskal-Wallis test suggests a statistically significant difference between groups (p=0,039), and Tukey for multiple comparisons, indicating a statistically significant difference between G3 and G4 (p<0.05). It was verified high prevalence of adhesive failures, followed by mixed failure and cohesive in dentin. The technique and the system used to dentin hybridization are able to affect the immediate bond strength of resin cement dual adhesive

Effects of coronal leakage on concentration of hydrogen ions and calcium release of several calcium hydroxide pastes over different periods of time

PURPOSE: To evaluate the effects of coronal leakage on concentration of hydrogen ions (pH) and calcium release of several calcium hydroxide pastes, over different periods of time. MATERIAL AND METHODS:  Fifty extracted human mandibular central incisors (n=10) were instrumented up to the F2 instrument and assigned to the following intracanal dressing: G1- Calen, G2- Calen with 0.4% chlorhexidine (CHX), G3- Calcium hydroxide with camphorated paramonochlorophenol (CPMC) and glycerin, G4- Calen, but temporary filling material maintained during all test (positive control) and G5- Root canal without intracanal dressing (negative control). All groups were immersed in distilled water for 7 days. In sequence, the temporary filling materials were removed, except in controls groups. All specimens were individually mounted on a specific device and only its root again immersed in distilled water. Concentration of hydrogen ions and calcium release by calcium hydroxide pastes in distilled water were evaluated in 24h, 7, 14 and 28 days. The results were submitted to ANOVA test (p = 0.05). After 28 days, root canals from experimental groups were examined in SEM. RESULTS: G1, G2, G3 and G4 presented similar pH values and calcium release and did not differ from each other (p>0.05), up to 7 days. After this time G1, G2 and G3 presented values lower values than G4 (p<0.05). In SEM analysis, calcium hydroxide residues were observed in all experimental groups. CONCLUSIONS: After 7 days, coronal leakage decreased the concentration of hydrogen ions and calcium ion release provided by all calcium hydroxide pastes

Efecto de agentes remineralizantes a base de fosfato de calcio sobre la dentina

Objetivos: Evaluar los efectos de agentes remineralizantes a base de fosfato de calcio en&nbsp;la obliteración de túbulos dentinarios y dispersión de energía en la dentina cervical.&nbsp;Material y métodos: Treinta especímenes de dentina cervical bovina fueron previamente&nbsp;erosionados (ácido clorhídrico al 0,6 %, pH 2,3; 5 min) y divididos aleatoriamente en 3&nbsp;grupos (n = 10): Control – sin tratamiento, NP – Desensibilize Nano P (FGM®) y RD – MI&nbsp;Paste Plus (RecaldentTM). Los tratamientos fueron aplicados en cuatro sesiones con&nbsp;intervalos de 7 días. Los especímenes fueron analizados por microscopia electrónica de&nbsp;barrido (MEB) y espectroscopia de rayos X de energía dispersiva (EDX).&nbsp;Resultados: Los&nbsp;grupos NP e RD mostraron mayor obliteración de túbulos dentinarios que el grupo control (p&nbsp;&lt; 0,05). Las concentraciones de Ca/P fueron similares entre todos los grupos evaluados.&nbsp;Conclusiones: Los agentes remineralizantes a base de fosfato de calcio demostraron ser&nbsp;una alternativa promisoria en la obliteración de túbulos dentinarios

Evaluation of the surface of root canal walls after utilization of endodontic rotary systems: SEM study

The objective of the present study was to determine, by scanning electron microscopy, the aspect of root canal walls after utilization of different rotary instrumentation systems for root canal preparation. Forty-two single-rooted and straight teeth were divided into six groups, whose root canals were prepared using the following rotary systems: groups 1 and 2 - Quantec; groups 3 and 4 - Pow-R; groups 5 and 6 - Profile. Irrigation was performed with 2.5% sodium hypochlorite solution in all groups, while only groups 2, 4 and 6 received a final flush with EDTA. Data were analyzed by non-parametric Kruskal-Wallis and Miller tests. Removal of the smear layer and other debris was more effective in the groups receiving EDTA as final irrigant. The Profile system showed the best cleaning, generating only a minimum smear layer, with a significant difference being observed compared to the Pow-R system (pO objetivo do presente estudo foi avaliar por meio de microscopia eletrônica de varredura, o aspecto superficial de paredes de canais radiculares apos uso de sistemas rotatórios de instrumentação endodôntica. Quarenta e dois dentes unirradiculados e com canais retilíneos foram divididos em seis grupos experimentais. Foram preparados utilizando-se os seguintes sistemas: Grupos 1 e 2 - Sistema Quantec; grupos 3 e 4 - Sistema Pow-R; grupos 5 e 6 - Sistema Profile. A irrigação foi realizada com solução de hipoclorito de sódio a 2.5% em todos os grupos durante a instrumentação. Apenas nos grupos 2, 4 e 6 foi realizada toalete final dos canais com solução de EDTA. O dados foram analisados pelos testes não paramétricos de Kruskal-Wallis e Miller. Foi observada maior remoção de smear layer e outros resíduos nos grupos onde foi realizada a toalete final com solução de EDTA. O sistema Profile mostrou melhor resultado, gerando menor quantidade de resíduos, com diferença significante quando comparado com o sistema Pow-R(

Fibrina rica en plaquetas (FRP): Una alternativa terapéutica en odontología

El objetivo de esta revisión, fue describir de una manera sencilla las principales características de la Fibrina Rica en Plaquetas (FRP), su composición, propiedades y aplicación clínica. La FRP, biomaterial autógeno y concen- trado plaquetario de segunda generación, es una matriz de fibrina que contiene leucocitos, plaquetas y factores de crecimiento, que son necesarios para los procesos de cicatrización, lo que brinda a este biomaterial, una gran utilidad en diversas áreas de la salud, incluyendo la odontología. Con esta revisión concluimos que la FRP es una alternativa real para mejorar la cicatrización de procedimientos quirúrgicos y potenciar otros biomateriales regenerativos en diversas áreas de la odontología, además de su accesibilidad y bajo costo