Influence of human and bovine substrate on the microleakage of two adhesive systems

Abstract

The aim of this study was to evaluate in vitro the marginal sealing of two adhesive systems and to analyze the influence of human and bovine substrates on marginal microleakage in enamel. Rectangular-shaped class V cavities (4 mm wide × 2 mm high × 2 mm deep) were made as follows: 8 cavities were prepared on the buccal and lingual surfaces of the human teeth with margins located on enamel and 16 cavities were prepared on the buccal surfaces of the bovine teeth. The cavities were randomly assigned to 4 groups of 8 cavities according to the adhesive system and substrate: G1 - Prime & Bond 2.1 (Dentsply)/human substrate; G2 - Adhese (Ivoclar/Vivadent)/human substrate; G3 - Prime & Bond 2.1 (Dentsply)/bovine substrate; G4 - Adhese (Ivoclar/Vivadent)/bovine substrate. The cavities were filled with microhybrid composite resin (Fillmagic) and after polishing/finishing procedures, the teeth were subjected to a thermocycling regimen of 500 cycles with 1-min immersions in water at 55° ±2°C and 5° ± 2°C. Next, the teeth were coated with two layers of nail polish to within 1 mm of the margin, submerged in a 50% silver nitrate solution for 2 h, rinsed thoroughly in running tap and immersed in developing solution for 8 h. The restorations were bisected resulting in 16 specimens. Microleakage was observed under a stereomicroscope at x25 and recorded using four-point (0-3) scoring system. The data were analyzed statistically by the Mann Whitney U-test at 5% significance level. Leakage was present in all specimens and there was statistically significant difference between the adhesive systems. Adhese self-etching system showed significantly more leakage in both substrates (human - p= 0.0001 and bovine - p= 0.0031). There was no statistically significant difference between human and bovine substrates for either of the adhesive systems based on different bonding mechanisms (Prime & Bond 2.1 - p= 0.6923 and Adhese - p= 0.6109). Neither of the adhesive systems was capable to completely prevent microleakage and the self-etching system was more susceptible to microleakage.

Long-term protective effect of surface sealants against erosive wear by intrinsic and extrinsic acids

“…Bovine enamel has been used in numerous studies investigating adhesion of dental adhesives [36][37][38] and sealing properties of surface sealants 31,39,40 . A resent study by Almeida et al (2009) showed no significant difference between human and bovine substrates concerning microleakage of adhesively fixed restorations in enamel 41 .…”

Bovine teeth as substitute for human teeth in dental research: a review of literature

“…Three of the seven studies found that microleakage values were higher in bovine compared to human substrates, both in enamel (7) and dentin (78,82). On the other hand, three studies found no significant differences in marginal microleakage between human and bovine teeth, both in enamel (83)(84)(85) and dentin (83,84). Camargo et al (86) showed that the penetration of 38% hydrogen peroxide bleaching agent into pulp chambers was higher in human teeth compared to bovine teeth, regardless of the restorative material used.…”

“…Inconsistent recommendations were proposed regarding the use of bovine substrate as an alternative to human substrate in bonding/adhesive strength studies. Table 4 illustrates seven in vitro studies reviewed in this category (7,78,(82)(83)(84)(85)(86). Three of the seven studies found that microleakage values were higher in bovine compared to human substrates, both in enamel (7) and dentin (78,82).…”

Enamel Wetness Effects on Bond Strength Using Different Adhesive Systems

“…Additionally, no significant differences in enamel microleakage have been observed between human and bovine substrates. 24 In order to standardize the adhesion area, enamel surfaces were mechanically flattened. This procedure, however, could potentially influence the shear bond strength because differing bonding behaviors have been reported 25 in ground and unground surfaces.…”