Bond strength of resin modified glass ionomer cement to primary dentin after cutting with different bur types and dentin conditioning

Abstract

he aim of this in vitro study was to evaluate the effect of different bur types and acid etching protocols on the shear bond strength (SBS) of a resin modified glass ionomer cement (RM-GIC) to primary dentin. Forty-eight clinically sound human primary molars were selected and randomly assigned to four groups (n=12). In G1, the lingual surface of the teeth was cut with a carbide bur until a 2.0-mm-diameter dentin area was exposed, followed by the application of RM-GIC (Vitremer -3M/ESPE) prepared according to the manufacturer's instructions. The specimens of G2, received the same treatment of G1, however the dentin was conditioned with phosphoric acid. In groups G3 and G4 the same procedures of G1 and G2 were conducted respectively, nevertheless dentin cutting was made with a diamond bur. The specimens were stored in distilled water at 37 o C for 24h, and then tested in a universal testing machine. SBS. data were submitted to 2-way ANOVA (= 5%) and indicated that SBS values of RM-GIC bonded to primary dentin cut with different burs were not statistically different, but the specimens that were conditioned with phosphoric acid presented SBS values significantly higher that those without conditioning. To observe micromorphologic characteristics of the effects of dentin surface cut by diamond or carbide rotary instruments and conditioners treatment, some specimens were examined by scanning electron microscopy. Smear layer was present in all specimens regardless of the type of rotary instrument used for dentin cutting, and specimens etched with phosphoric acid presented more effective removal of smear layer. It was concluded that SBS of a RM-GIC to primary dentin was affected by the acid conditioning but the bur type had no influence.

Antibacterial and Mechanical Assays of Resin Modified Glass Ionomer Containing Propolis Extract

“…The mean shear bond strength of 0% EEP, 10%, 25% and 50% mixture in this study was 8.25, 7.82, 6.87, and 3.85 MPa, respectively. This agrees with the study of Carrara et al (67) and Di Nicoló et al (68) who found that the shear bond strength of 0% EEP recorded 9.02 and 8.33 MPa, respectively; however, El-Kalla and Garcia-Godoy (69) reported 16.9 MPa.…”

Effect of Prewarming and/or Delayed Light Activation on Resin-Modified Glass Ionomer Bond Strength to Tooth Structures

“…Application of phosphoric acid has previously been reported to be effective in increasing the bond strength of light-cured glass ionomers to enamel. 27,28 It is probable that if a stronger acidic conditioner, such as phosphoric acid, is used for the enamel surfaces, a higher initial bond strength will be achieved when the material is light cured immediately after insertion, based on manufacturer's recommendations. In such a situation, it seems that it is better for the handling of the material to be similar to that with the composite resin, and delaying the light-activation procedure should be avoided so that acid-base reactions will not have an opportunity to proceed immediately; however, further studies are necessary in this regard.…”

The Effect of Various Bur Types and Two Bonding Agents on Shear Bond Strength of Composite Resin to Dentin

“…(11,12) In addition to that the hybrid layer formed by self etch adhesive systems thinner than that formed by total etch adhesive systems (13,14) In the self-etch adhesive groups the shear bond strength obtained after dentin preparation with carbide fissure bur higher than that obtained when diamond fissure bur were used. This due to that dentin prepared with diamond burs present a more irregular dentin surface with a visible thicker smear layer when compared to carbide burs treated groups (2,7) . The presence of smear layer on dentin surface restrains the effective contact between restorative material and dentinal tissue impairing satisfactory adhesion.…”

“…The surface cut with diamond burs examined by scanning electron microscope present more irregularities and thicker smear layer when compared to the dentin surface cut with carbide burs. (1,2) Dentin bonding systems have been improved in order to promote durability and reliability of adhesive restorations (3) . The mechanisms of adhesion of currently used adhesive, depending on clinical approach to the smear layer: it can be removed by acids (the fourth generation and the fifth generation) or dissolved by self etching primers(the sixth generation and seventh generation).…”