ABSTRACT
Objective To compare the occluding effect of conventional penetrating resin,Single Bond desensitizer,and penetrating resin combined with ethanol wet-bonding on dentin tubules.Methods Sixty isolated premolar teeth were prepared to form dentin discs.The 60 teeth were divided into 3 groups based on a random number table:Group A,conventional penetrating resin;Group B,Single Bond desensitizer,and Group C,penetrating resin combined with ethanol wet-bonding.Each group comprised 20 teeth.Dentin discs were split in half along the longitudinal axis.Half of the disc served as the control;the other half was coated with desensitizer.Microscopic characteristics of the dentin surface and profile were determined by using a field emission scanning electron microscope.Results In group A,70.10％±2.13％ of the dentin tubule openings were covered by the resin.The penetration depth was 50±10.59 μm,and the resin was short and discontinuous.In group B,86.35％±1.73％ of the dentin tubules openings were covered.The penetration depth was 69± 11.98 μm,and the resin was sparse.In group C,95.65％± 1.46％ of dentin tubules openings were covered.The penetration depth was 177±9.17 μm,and the resin was compact and filled.Conclusion Penetrating resin combined with ethanol wet-bonding occludes dentin tubules better than conventional penetrating resin and Single Bond desensitizer.
ABSTRACT
El objetivo de este trabajo "in vitro" fue evaluar la resistencia de unión de dos sistemas adhesivos utilizando el ensayo de microtracción, variando el tipo de substrato dentinario. Fueron utilizados 32 terceros molares humanos recientemente extraídos, los cuales fueron divididos en cuatro grupos de acuerdo con la orientación de los túbulos dentinarios (paralelos o perpendiculares) y con el tipo de sistema adhesivo utilizado (convencional o auto-acondicionante). Además de evaluar la resistencia de unión, todas las muestras fueron examinadas visualmente para determinar el tipo de fractura. Posteriormente, los resultados fueron sometidos a análisis estadística, permitiendo concluir que los adhesivos autoacondicionantes poseen un mejor comportamiento, mostrando mayor resistencia de unión a la dentina cuando los túbulos dentinarios están expuestos paralelamente al largo del eje del elemento dentario. Sin embargo cuando los túbulos dentinarios están perpendiculares al eje del diente, los sistemas adhesivos convencional y autoacondicionantes poseen resistencia adhesiva semejante. En cuanto al tipo de fractura de los cuerpos de prueba, las fallas adhesivas son predominantes, independiente del sistema adhesivo utilizado y del tipo de substrato dental
The aim of this in vitro study was to evaluate the microtensile bond strength, for two adhesive systems, varying the dentin substrate. Thirty-two recently extracted third molars human were used, and divided in four groups according to the dentin tubules orientation (parallels and perpendiculars) and the adhesive systems (total-etching and self-etching). The specimens were examined by optical microscope for determined the fracture type. After, the statistical analysis was evaluated, allowing to conclude that the self-etching adhesive systems showed better behavior and greater bond strength for dental substrate, when the dentin tubules were parallel exposited to dental axis. Nevertheless, when the dentin tubules were perpendiculars, the total-etching and self-etching adhesive systems showed similar statistical bond strength values. For the fracture type of the specimens, adhesive fractures were predominant, independent of the adhesive systems and the type of dental substrate used
Subject(s)
Dental Cements , Dental Materials , In Vitro Techniques , Metal Ceramic AlloysABSTRACT
La unión adhesiva es requisito básico para retener y sellar las restauraciones de resina compuesta. Determinar la influencia de la dirección de los túbulos dentinarios en la resistencia al cizallamiento de 2 sistemas adhesivos y determinar tipo de fractura. 40 terceros molares humanos sanos, fueron divididos a la mitad, montados en acrílico y desgastados con papel de lija, bajo agua para exponer los túbulos dentinarios transversalmente (especímenes #1 al #40) y longitudinalmente (especímenes del #41 al #80). Se separaron en 4 grupos, tratados con: Grupo A (especímenes #1 al #20): adhesivo de dos etapas, One Coat Bond® (Coltene®), Grupo B (especímenes #21 al #40): adhesivo autograbante, Adper® Prompt® (3M® ESPE®), Grupo C (especímenes #41 al #60): One Coat Bond® y Grupo D (especímenes #61 al #80): Adper® Prompt®. Sobre los adhesivos se construyeron cilindros de resina restauradora Filtek® Supreme (3M® ESPE®). Los especímenes fueron sometidos a pruebas de cizallamiento en una máquina de ensayos universal Instrom®. Los datos fueron analizados estadísticamente por medio del test t de Student. Resultados: Grupo A: 16,9 Mpa (± 8,8), Grupo B: 20,2 Mpa (± 9,12), Grupo C: 14,2 Mpa (± 7,4) y Grupo D: 11,9 Mpa (± 6,11). La dirección de los túbulos dentinarios afecta directamente los valores de resistencia al cizallamiento sólo en el adhesivo autograbante (p=0,002). El adhesivo de dos tiempos mostró valores similares en ambas direcciones de los túbulos (p=0,297). Al MEB la fractura mixta fue la observada con mayor frecuencia (60%)
The adhesion is a basic requirement to seal and retain the resin based composite restorations. To determine the influence of the dentin tubules orientations in shear bond strength (SBS) of 2 adhesive systems and to determine the type of fracture. Method: 80 specimens were obtained from 40 healthy human third molars, they were mounted in acrylic molds and polished under tap water - SiC paper 400 grit - to expose the dentin tubules cross section (specimen #1 - #40) and lengthwise of them (#41 - #80). Four groups were formed and treated with: Group A (specimens #1- #20): One Coat Bond® (Coltene®) a two step adhesive; Group B (specimens #21 - #40): Adper® Prompt® (3M® ESPE®) a self-etch adhesive; Group C (specimens #41 - #60): One Coat Bond® and Group D (specimens #61 - #80): Adper® Prompt®. After the adhesive procedures, a composite cylinder, Filtek® Supreme (3M® ESPE®) was built for SBS test, that was carried out in an Instrom® Universal Testing Machine. The Bond Strength data were analyzed with t-test. Group A: 16.9 Mpa (±8,8), Group B: 20.2 Mpa (±9, 12), Group C: 14.2 Mpa (±7, 4) and Group D: 11.9 Mpa (±6, 11). It was concluded that dentin tubules orientation affects the SBS only in the self-etch adhesive (p=0.002). Two step adhesive showed similar SBS in both tubule orientations (p=0.297). Observation by SEM showed the mix fracture was the most frequent (60%)