Characterization of Dentine to Assess Bond Strength of Dental Composites

Abstract

This study was performed to develop alternating dentine adhesion models that could help in the evaluation of a self-bonding dental composite. For this purpose dentine from human and ivory was characterized chemically and microscopically before and after acid etching using Raman and SEM. Mechanical properties of dentine were determined using 3 point bend test. Composite bonding to dentine, with and without use of acid pre-treatment and/or the adhesive, were assessed using a shear bond test. Furthermore, micro gap formation after restoration of 3 mm diameter cavities in dentine was assessed by SEM. Initial hydroxyapatite level in ivory was half that in human dentine. Surface hydroxyapatites decreased by approximately half with every 23 s of acid etch. The human dentine strength (56 MPa) was approximately double that of ivory, while the modulus was almost comparable to that of ivory. With adhesive use, average shear bond strengths were 30 and 26 MPa with and without acid etching. With no adhesive, average bond strength was 6 MPa for conventional composites. This, however, increased to 14 MPa with a commercial flowable “self–bonding” composite or upon addition of low levels of an acidic monomer to the experimental composite. The acidic monomer additionally reduced micro-gap formation with the experimental composite. Improved bonding and mechanical properties should reduce composite failures due to recurrent caries or fracture respectively.

Characterization of Polylysine Enriched Self-Adhesive Resin Cements

“…This result was confirmed by Khan [16], Liaqat [30], Lygidakis [38], Panpisut et al [39], and Katsimpali [40].…”

“…HEMA, when uncured, absorbs water; this can lead to monomer dilution and thereby halt the polymerization process. Following polymerization, poly-HEMA also attracts water and produces hydrogels, reducing the polymer's mechanical strength [30]. According to the study's findings, PLS addition had no discernible effect on either cement's compressive strength, except resin cement, which included 5% PLS.…”

Methacrylate peak determination and selection recommendations using ATR-FTIR to investigate polymerisation of dental methacrylate mixtures

“…However, as O-H bending vibrations absorb in the same region, and spectral contributions of carbonyl groups may affect the 1640 cm -1 peak, alternative peak selections are recommended [15]. The 1320 cm -1 [v(C-O)] has been successfully employed for the study of polymerisation in dental composites and has been preferred over the 1640 cm -1 peak in a number of cases [9,11,16]. Despite having some studies acknowledge the variability regarding peak selection, the 1320 cm -1 peak is still underappreciated [17].…”

Varying 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) level improves polymerisation kinetics and flexural strength in self-adhesive, remineralising composites

“…Previously, 4-META was included in the UDMA/PPGDMA to further improve adhesion promotion in dentine. It was also proposed it might provide a bond between the monomer and these hydrophilic particles [32,43]. The increase in strength seen above with 4-META addition provides evidence that this interface bonding might be occurring.…”