Cervical Microleakage in MOD Restorations: In Vitro Comparison of Indirect and Direct Composite

Abstract

Clinical RelevanceOne of the advantages reported for indirect composite restorations is the reduction of polymerization shrinkage, which could produce better marginal sealing. Although sealing of cervical enamel margins was slightly better for the indirect systems used, no difference between indirect and direct restorations was found for cervical margins in cementum/dentin. SUMMARYThis study compared microleakage between indirect composite inlays and direct composite restorations. Forty-eight standard inlay MOD cavities, with cervical margins located either in enamel or dentin, were prepared in extracted human third molars. The specimens were randomly divided into 3 groups (n=16). In the control group, the cavities were restored with the composite Filtek Z250 (3M ESPE). For the experimental groups, indirect restorations were made with the Artglass (Heraeus-Kulzer) or Belleglass HP (Kerr Laboratories) systems and cemented with the dual curing cement RelyX ARC (3M ESPE). The adhesive system Single Bond (3M ESPE) was applied on all groups. The specimens were submitted to thermolcycling, coated with nail varnish, then immersed in 2% basic fuchsine aqueous solution for 24 hours. The teeth were then sectioned and leakage scores were evaluated (40x), based on a standard ranking. Data were submitted to statistical analysis (Mann-Whitney and Kruskal-Wallis tests) with a 95% confidence level. No statistical difference was found between substrates (p=0.595), and the materials performed similarly in dentin (p=0.482). Direct restorations showed higher leakage than indirect restorations at the enamel margins (p=0.004). Within the limitations of this experimental design, overall leakage was similar between both substrates, while the indirect systems provided a better sealing than direct composites only in enamel.

Fracture Resistance and Gap Formation of MOD Restorations: Influence of Restorative Technique, Bevel Preparation and Water Storage

“…5 SEM examination of gap formation at the cervical wall showed good marginal adaptation for all groups tested after 24 hours. It has been reported that initial bonding resistance 29 and initial marginal adaptation 25 are adequate with new adhesive systems, especially when the margins are located in enamel. 30 In fact, the interlocking formed by penetration of the adhesive system inside the microgaps originated by acid etching in highly mineralized enamel has been reported to be a more secure, stable bonding than adhesion obtained with dentin.…”

“…In a recent study, better marginal sealing was observed for indirect composite restorations in enamel when compared to direct composite restorations. 25 The bevel was also applied in order to produce a long lasting adhesive interface and, based on observations from this study, beveled restorations generally exhibited better fracture resistance and less gap formation initially and after six months.…”

“…Since polymerization shrinkage has been associated with deleterious effects at the adhesive interface, [24][25] different restorative techniques have been advocated to minimize the harmful effects on restoration longevity. The indirect technique proposed in this study was employed to restrict polymerization shrinkage to resin cement and, as a consequence, reduce the adverse effects generally observed with long-term storage.…”

Polymerization Shrinkage of Different Types of Composite Resins and Microleakage With and Without Liner in Class II Cavities

“…Microleakage may result from many factors, including adaptation of resin material to the tooth surface, the adhesive system used, and polymerization shrinkage of materials used. 20,21 Dye penetration is one of the most frequently used methods to evaluate microleakage. 21,22 In the current study, a dye penetration test was used because it is simple and relatively cheap and provides quantitative and comparable results.…”

“…20,21 Dye penetration is one of the most frequently used methods to evaluate microleakage. 21,22 In the current study, a dye penetration test was used because it is simple and relatively cheap and provides quantitative and comparable results. This method does have some limitations, however, such as subjectivity of reading and high diffusability of dyes due to their low molecular weight.…”