Interfacial morphology of self-etching adhesive systems in dentin.
ABSTRACT To portray and assess the interfacial morphology achieved with self-etching systems in dentin under observation by scanning electron microscopy.
Ten caries-free extracted erupted human third molars were used in this study. The occlusal enamel was removed, and 10 dentin disks with a thickness of 800 +/- 200 Microm were obtained by slow-speed sectioning with a diamond saw parallel to the occlusal surface. A standard smear layer was created on the occlusal surface by wet sanding with 600-grit sandpaper for 60 seconds. The dentin disks were randomly assigned to one of the systems: AdheSE (Ivoclar Vivadent), Optibond Solo Plus-Self-Etch (Kerr), Tyrian SPE (Bisco) as self-etching primers, and Adper Prompt Self-Etch (3M Espe) and One-Up Bond F (Tokuyama) as self-etching adhesives. All systems were applied according to the manufacturers' instructions. After application of the adhesive systems, a 1.0-mm-thick layer of a flowable composite resin (Filtek Flow; 3M Espe) was applied to the treated dentin surface and light cured for 40 seconds. The specimens were then processed for observation by scanning electron microscopy.
All self-etching systems achieved the formation of sealed interfaces and hybridized areas with variable extents except for the self-etching adhesive One-Up Bond F, which showed some gap formation and poor hybridization. Optibond Solo Plus-Self-Etch presented a more consistent adhesive interface with thicker hybrid layers, numerous resin tags, and lateral branches.
Regarding the micromorphology aspect, Optibond Solo Plus-Self-Etch showed the finest result, while One-Up Bond F was not able to produce a satisfactory ultrastructural morphology.
- [show abstract] [hide abstract]
ABSTRACT: Problems that may arise in resin composite Class 2 restorations include microleakage and postoperative sensitivity. However, limited in-vivo research is conducted to evaluate these processes. The aim of this study was to assess postoperative sensitivity, microleakage and the pooling of adhesives in relation to Class 2 box-type composite restorations placed in vivo using various adhesive systems and application techniques. One hundred and forty-four Class 2 box restorations were placed in the mesial and distal surfaces of 72 premolar teeth in-vivo using one of three combinations of adhesive systems and three filling techniques. After 6 weeks of clinical service postoperative sensitivity was recorded. The teeth were then extracted, immersed in a dye solution and sectioned. Microleakage and pooling of the adhesive was recorded. Statistical analysis involved logistic regression and chi2 tests to identify differences between groups at p < 0.05. Of the 144 restorations, 65 showed minimal cervical leakage in enamel, 5 suffered leakage into dentin and 74 were free of microleakage. No statistically significant differences were found in cervical microleakage between the adhesive systems or between filling procedures. Occlusal microleakage in the enamel was present in 16 of the 160 restorations. Liner Bond 2 restorations leaked significantly more at the occlusal surface (p < 0.05). Pooling of the adhesive was significantly less when PhotoBond was used. No spontaneous postoperative sensitivity was reported. Twenty-eight restorations were sensitive to loading. Postoperative sensitivity was significantly less in patients with Liner Bond 2 restorations. The adhesive systems used in this study showed minimal leakage into dentin in vivo. Using Liner Bond 2, restorations exhibited more occlusal leakage but were significantly less sensitive to loading.Journal of Dentistry 10/1998; 26(7):555-62. · 3.20 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: The effectiveness of 4-methacryloxyethyl trimellitate anhydride (4-META) on the adhesion of an acrylic rod with etched dentine and enamel was studied. Etching of tooth substrates with a 10% citric acid-3% ferric chloride solution prior to the adhesion proved effective. Monomers with both hydrophobic and hydrophilic groups like 4-META promoted the infiltration of monomers into the hard tissue. The infiltrated monomers polymerized in situ and good adhesion with the tooth substrates took place. The tensile adhesive strength was 18 MPa on the etched dentine. Scanning electron microscopic studies suggested that the monomers possess affinity with the hard tissue. The good adhesion was not provided by the interlocking at the tubules as had been considered previously.Journal of Biomedical Materials Research 04/1982; 16(3):265 - 273.
Article: Bonding to intact dentin.[show abstract] [hide abstract]
ABSTRACT: It has been reported that the presence of a smear layer on dentinal substrates can compromise bonding. Typically, smear layers are removed by acidic agents that selectively extract calcium salts from dentin surfaces to leave a collagen-rich substrate. Acid-conditioned dentin (i.e., demineralized) is then primed and an adhesive agent applied. In the present study, we removed smear layers by "polishing" dentin specimens with a hydroxyapatite paste and ultrasonication. Bonding procedures were carried out by means of an aqueous solution of 20% 2-methacryloyloxyethyl phenyl phosphoric acid (phenyl-P) and 30% 2-hydroxyethyl methacrylate, referred to as 2OP-30H, a "self-etching primer". The 20P-30H solution was applied to "intact" dentin (i.e., non-demineralized) for either 30 or 60 s. Control samples received no application (O s) of the self-etching primer. Mean tensile bond strengths (10 MPa) were similar in both the 30-second- and 60-second-primed groups. The widths of formed hybrid layers varied from 0.3 +/- 0.2 micron at O s application (control) to 2.1 +/- 0.3 micron for the 30-second group and 4.1 +/- 0.2 micron for the 60-second group. SEM and TEM observations revealed that the 20P-30H self-etching primer created diffusion channels into "intact" calcium-rich dentin which permitted monomer to infiltrate dentin substrates. Hybrid layers identified under microscopic examination demonstrated resistance to both HCI and NaOCI treatments, suggesting that the hybrid layer was not defective, and that bonding was stable.Journal of Dental Research 10/1996; 75(9):1706-15. · 3.83 Impact Factor