Marginal integrity and microleakage of direct and indirect composite inlays: SEM and stereomicroscopic evaluation

Abstract

ABSTRACT:The aim of this study was to evaluate the microleakage of direct and indirect composite inlays by stereomicroscopy and scanning electron microscopy (SEM). Thirty bovine incisors were ground to obtain an incisal platform, simulating the occlusal surface of a human molar. Each tooth received two 8° proximal cavities with cervical finishing line prepared in dentine or enamel. One of the cavities was filled with Filtek Z250/Single Bond, using the direct technique, and the other was filled with with Solidex/Rely X ARC/Single Bond, using the indirect technique. The samples were stored in water at 37°C for 24 hours and placed in a 50% silver nitrate solution for 6 hours in a dark container. Next, the samples were washed under running water, immersed in a developing solution and exposed to fluorescent light for 12 hours. The teeth were then severed and evaluated for dye penetration by stereomicroscopy and SEM. There were no significant differences between the direct and indirect techniques for the cervical finishing line in enamel, but for the finishing line in dentin, the indirect technique allowed less microleakage than the direct technique. SEM analysis showed leakage similar to that observed by stereomicroscopic analysis. The use of stereomicroscopic and SEM evaluations improves microleakage analysis. DESCRIPTORS: Composite resins; Dental restoration failure; Dental leakage; Marginal adaptation (dentistry). RESUMO:O objetivo deste estudo foi avaliar a microinfiltração em restaurações diretas e indiretas em resina composta por meio de estereomicroscopia e microscopia eletrônica de varredura (MEV). Trinta incisivos bovinos foram lixados de forma a produzir uma plataforma incisal, simulando a face oclusal de um molar humano. Cada dente recebeu dois preparos proximais com 8º e término cervical em esmalte ou dentina. Uma cavidade foi restaurada pela técnica direta com Filtek Z250/Single Bond, e a outra pela técnica indireta com Solidex/RelyX ARC/Single Bond. As amostras foram armazenadas em água a 37°C por 24 horas e então imersas em solução de 50% de nitrato de prata por 6 horas em recipiente escuro. As amostras foram lavadas em água corrente, imersas em solução reveladora e expostas à luz fluorescente por 12 horas. Os dentes foram seccionados para avaliação da penetração do marcador em lupa estereoscópica e MEV. Não houve diferença entre as técnicas direta e indireta para o término em esmalte, porém, para o término em dentina, a técnica indireta resultou em menor infiltração. MEV mostrou infiltração similar à da lupa estereoscópica. A análise por meio de lupa estereoscópica e MEV melhora a avaliação da microinfiltração. DESCRITORES: Resinas compostas; Falha de restauração dentária; Infiltração dentária; Adaptação marginal (odontologia). INTRODUCTIONAdequate polymerization of resin composite is considered to be a very important factor for assuring appropriate physical and biological properties. Shrinkage stress, however, is one of the inherent disadvantages that occur when visible light-activated resin composit...

Marginal microleakage of class II composite resin restorations due to restorative techniques

“…If the margins are localized around 1.0 mm coronal to the CEJ a good marginal integrity may result following a conventional enamel acid etching (17). Soares et al (18) evaluated the marginal integrity and microleakage of direct and indirect composite inlays in cavities with cervical finishing line prepared in dentine or enamel. There were no significant differences between the direct and indirect techniques for the cervical finishing line in enamel, but for the finishing line in dentin, the indirect technique allowed less microleakage than the direct technique.…”

“…There were no significant differences between the direct and indirect techniques for the cervical finishing line in enamel, but for the finishing line in dentin, the indirect technique allowed less microleakage than the direct technique. Thus, the authors decided to assemble the end cervical cavities with 1 mm below the CEJ, as are those most likely to microleakage and therefore there is greater need for studies to obtain satisfactory restorations (18). The dimensions of the cavity used in the present study were chosen because they represent the modern cavities that are indicated in the clinical practice.…”

Efectos sobre microdureza y grado de conversión de dos tipos de resinas sometidas a tratamientos de pospolimerización

“…Las restauraciones de resina compuesta indirecta han demostrado menor microfiltración en la interfase diente-restauración, debido a la eliminación del estrés contracción y contracción volumétrica [6]. A pesar de esta disminución, se han encontrado monómeros libres no polimerizados que indican la necesidad de complementar uniones de dupla carbono por medio de procesos alternativos de curado [7].…”

Diametral tensile strength of composite resins submitted to different activation techniques

“…Shrinkage stress, however, is one of the inherent disadvantages that occur when visible lightactivated resin composites are submitted to light polymerization. Direct composites have also been associated with undesirable characteristics such as excessive wear, deficient interproximal contacts, microleakage and postoperative sensitivity 1,7,9,12 . Indirect systems became popular to overcome these limitations of direct restorations 12,13 .…”

“…Direct composites have also been associated with undesirable characteristics such as excessive wear, deficient interproximal contacts, microleakage and postoperative sensitivity 1,7,9,12 . Indirect systems became popular to overcome these limitations of direct restorations 12,13 . Post-curing of light-cure composite material was introduced more than a decade ago 1,[6][7][8]10,13,15 .…”