In vitro evaluation of adhesive characteristics of 4-META/MMA-TBB resin with organic filler

Abstract

Dentin Self etching a b s t r a c tObjectives. A commercial restorative material, BondfillSB (BF), is a modification of 4-META/MMA-TBB resin cement. BF uses a self-etching primer and added pre-polymerized organic fillers. We compared BF with another self-etching system, EasyBond (EB), in shear bond strength, bonded interface characteristics to human dentin and contraction gap when used in bulk-filling.Methods. Shear bond strength of BF and EB + Z100 (Z), bonded by different experience-level operators, was evaluated. Bonded interfaces were characterized by SEM, AFM, and AFM based nano-indentation. Contraction gaps (CG) at 0 h and 24 h after polymerization were evaluated for BF or EB bulk filled class I cavities. To meet the clinical recommendation, BF's powder was replaced by experimental radioopaque powder (BFO) for the CG study. EB was used with Z (EBZ) or with a resin marketed for bulk-fill base (SureFil-SDR-flow (EBSF)).Results. Shear bond strengths (Mean ± Standard Deviation (S.D.)) of BF (37.4 ± 2.6 MPa; n = 36) were higher and less variable than EBZ (18.2 ± 7.6 MPa; n = 36) (p < 0.0001, One-way ANOVA).Weibull characteristic strength (Á) differed significantly between materials (p < 0.0001) but not between operators (p = 0.90). EBZ often had non-uniform interfaces and a wider band of reduced elastic modulus (E) of greater than 20 m across the interface. BF had uniform interfaces and a smaller width of affected dentin under the interface (∼1 m). There was a difference in dentin-E between EBZ and BF up to 9 m from the interface (mixed-effects model; P = 0.03). A stratified linear regression model used for CG. EBSF and BFO showed significantly smaller CG than EBZ at time 0. None of three combinations showed any significant change between 0h-CG and 24h-CG.Significance. BF possessed bonding characteristics required to serve as a restorative.

Long‐term marginal adaptation and nanoleakage of class V cavity restored with organic filler filled 4‐META/MMA‐TBB resin

“…At dentin bonding interface, Z100 applied with self‐etching adhesive showed larger variation in elastic modulus from the bonded interface to the restoration material. While in BF, the transitional zone was consistent and closed to the elastic modulus of the restorative material . As a result, these materials might lead to differential stress concentrations at different bonding interfaces.…”

“…Therefore, marginal adaptation and nanoleakage expression at the interface between the restoration and tooth hard tissue could be considered essential characteristics affecting the long‐term behavior of restorative material. It is reported that Bondfill SB had a high shear bond strength (37.4 ± 2.6 MPa) to dentin . But there is no report about the interface performance after aging.…”

“…Compared to conventional CRs containing brittle heavy inorganic fillers ( E modulus is about 10–13 GP), Bondfill SB filled with organic fillers is characterized with reduced viscosity and behaves more resiliently ( E modulus is about 2.0 GP). In addition, Bondfill SB using a brush‐on additive technique may be less technique sensitive than conventional CRs using an incremental filling technique, as the later require a careful application to reduce contraction force, such as incremental placement, to avoid undesired clinical outcomes …”

Effect of time and dental substrate on the bond strength of a universal adhesive system: in vitro study

“…The polymerization shrinkage comes from converting the monomers present in the resins into polymers, which can result in gaps at the interface between the restoration and the dental substrate 8,9 . What occurs if the shrinkage stress lives more significant than the bond strength of the adhesive to the substrate, and there is a buildup of tension that can lead to microcracks or detachment at the adhesive interface 10 .…”

Chemical interaction of 4-META with enamel in resin-enamel bonds

“…Numerous studies have provided structural evidence of resin-tooth bonds using optical microscopy and scanning microscopy analyses [1][2][3][4][5] . Microscopy analyses have clarified the structural information concerning the hybrid layer, micro resin tag structure, nanoleakage pattern, and water tree or bubble formation [6][7][8] .…”