The effect of different ratios of nano‐sized hydroxyapatite fillers on the micro‐tensile bond strength of an adhesive resin

Abstract

The purpose of this study was to evaluate the micro‐tensile bond strength (μTBS) of dentin bonding agents containing different ratios of nano‐sized hydroxyapatite fillers (HA). X‐ray diffraction analysis was used for characterization, and scanning electron microscope (SEM) analysis was used to determine the HA particle size after that HA were mixed a bonding agents without filler. Dentin bonding agents were divided into four groups according to addition of different ratios of nano‐sized hydroxyapatite fillers as 2% HA, 5% HA, 7% HA, and no‐filler control group. The teeth (n = 32) were sectioned with a low‐speed diamond blade under water cooling to expose the mid‐coronal dentin. Following the bonding application, restorations were applied incrementally. Each tooth was cut on the x and y axis, and each specimen was fixed to a testing device and stressed until failure occurred. The debonded specimens were examined under 250× magnification without a coating layer at 2.00 kV using a SEM to determine failure patterns. μTBS data were analyzed using a anova and Tukey's post hoc test. The failure mode data were analyzed using the Chi‐Square test. The maximum mean value of μTBS was in the 7% HA group, while the minimum mean value of μTBS was observed in the control group. 7% HA group was statistically significant and higher than other groups while there were no significant differences between the control, 2% HA, and 5% HA groups. According to SEM analysis, fracture analysis revealed that the mixed fracture type was seen more often than the other fracture types. The particle size and amount of HA fillers added to the adhesive resin seem to affect the success of the bond strength to the dentin. Adding different ratio nano‐sized HA fillers to the adhesive resin contributed positively to the immediate μTBS values in the dentin.

Modifying Adhesive Materials to Improve the Longevity of Resinous Restorations

“…Particularly they could serve as nuclei in excess demineralized dentin regions lacking the HA crystal nuclei. Thus, demineralized zones in hybrid layer region could be remineralized [83].…”

“…Bioactive glass (BAG), calcium phosphate (CaP), and HA could potentially be used as a source of CaP and as an adjunct to biomimetic remineralization, allow epitaxial deposition of CaP on their external surfaces [83]. The endogenous MMPs fossilized by the growth of apatite mineral, consequently protecting collagen fibrils [85].…”

“…Hypotheses have been proposed that HA nanorods in adhesives may biomineralize with the collagen network of tooth through hydrogen bonding between COOH, OH, and NH 2 of the collagen network and OH group of the hydroxyapatite particles, achieving remieralization of the dentin at resin-dentin interface [93]. It was demonstrated that adding 7 wt% nano-sized HA fillers to SBMP (3M, St Paul, MN, USA) adhesive resin contributed positively to the immediate micro-tensile bond strength values in the dentin [83].…”

Dentin Bond Integrity of Hydroxyapatite Containing Resin Adhesive Enhanced with Graphene Oxide Nano-Particles—An SEM, EDX, Micro-Raman, and Microtensile Bond Strength Study

“…As the dental adhesives come in direct contact with the tooth dentin, incorporation of HA nano particles in resin adhesives can possibly remineralize the caries affected dentin. In addition, interaction of HA within the hybrid dentin layer forming an organic bond, will contribute positively to its bond strength to tooth [19]. In an earlier study, Leitune et al reported that inclusion of nano-HA particles in the experimental adhesive improved its bond strength to dentin [20].…”

Effects of Zn-Doped Mesoporous Bioactive Glass Nanoparticles in Etch-and-Rinse Adhesive on the Microtensile Bond Strength

“…This mechanism remineralizes the demineralized regions within the hybrid layer to increase the long-term stability of DAs [ 39 ]. Kavrik reported that MBN induces biomimetic remineralization as a source of CaP [ 55 ]. The DA-MBN and DA-MBN-Zn utilized in this study release Ca 2+ and PO 4 3− and may induce biomimetic remineralization ( Figure S3 and Table S2 ).…”