Shear bond strengths of ceramic brackets bonded with different light-cured glass ionomer cements: an in vitro study

Abstract

The purpose of this study was to evaluate the shear bond strengths of four light-cured glass ionomer cements used for direct bonding of ceramic brackets, and to compare the results with a two-paste chemically-cured composite resin. Two commercially available polycrystalline ceramic brackets, with either chemically or mechanically retentive bracket bases, were evaluated. The brackets were bonded to 100 freshly extracted bovine incisors, and, after storage in tap water at room temperature for 24 hours, they were subsequently tested in a shear mode using a universal testing machine. The maximum bond strength and the site of bond failure were recorded. With the mechanically retentive base, Fuji Ortho LC produced the highest bond strength (18.50 MPa), which was not significantly different from the values achieved with Concise (14.88 MPa) (P > 0.1) and Photac Bond (13.86 Mpa) (P = 0.1). The lowest bond strength was provided by locomp A20 (5.23 MPa). With the chemically retentive base, the highest bond strength was measured with Concise (29.27 MPa), which was significantly (P < 0.01) higher than the values for Photac Bond (16.27 MPa) and Fuji Ortho LC (13.48 MPa). Again locomp A20 produced the lowest bond strength (3.21 MPa). Three cements (Dyract Ortho, locomp A20 and Fuji Ortho LC) provided higher shear bond strengths with the mechanical retention system, whereas Concise and Photac Bond gave higher strengths with the silane-treated bracket bases. However, the strengths were statistically significantly different only for locomp A20 (P = 0.001) and Concise (P = 0.001). With the mechanically retentive base, Dyract Ortho and locomp A20 failed at the enamel-adhesive interface, whereas Photac Bond and Concise debonded at the bracket-adhesive interface. Fuji Ortho LC failed at both, the bracket-adhesive (40 per cent) and the adhesive-enamel (60 per cent) interface. With the chemically retentive base, all the adhesives failed at the enamel-adhesive interface. Only one bracket fracture occurred in this study, and no enamel damage was detected.

Plasma versus Halogen Light: the Effect of Different Light Sources on the Shear Bond Strength of Brackets*

“…While the composite investigated by Sfondrini et al [49] achieved a significantly higher bond strength after 24 h than a resinreinforced glass ionomer cement, regardless of the light source used, the composites Transbond™ XT and Kurasper ® F in the present study only achieved higher bond strengths than Fuji Ortho™ LC (Figures 3 and 5) at a layer thickness of 1 mm. In a study by Cacciafesta et al [5] of different resin-reinforced glass ionomer cements and the chemically-curing classic composite Concise™ orthodontic bonding system, the highest bond strengths for the mechanically retentive base of the Transcend™ 6000 system were actually achieved with Fuji Ortho™ LC. Knox et al, on the other hand, observed a lower bond strength with Fuji Ortho™ LC, claiming that this was the result of its lower cohesive strength as compared to the composites [29].…”

“…In einer Untersuchung von Cacciafesta et al [5] mit verschiedenen kunststoffverstärk-ten Glasionomerzementen und dem chemisch härtenden klassischen Komposit Concise™ orthodontic bonding kamen die höchsten Verbundfestigkeiten für die mechanisch retentive Basis des Transcend™ 6000-Systems sogar mit Fuji Ortho™ LC zustande. Knox et al [29] fanden hingegen eine geringere Verbundfestigkeit von Fuji Ortho™ LC und begründen dies mit dessen geringerer kohäsiver Festigkeit im Vergleich zu den Kompositen.…”

“…Besides composites, resin-modified glass ionomer cements have stood the test as bracket adhesives [5,30,32,33,51]. These consist of glass ionomer and composite components, and cure as a result of both acid-base reactions and polymerization.…”

“…Als Bracketadhäsive haben sich neben den Kompositen auch kunststoffmodifizierte Glasionomerzemente bewährt [5,30,32,33,51]. Sie bestehen aus Komponenten von Glasionomeren und Kompositen und binden sowohl durch Säu-re-Base-Reaktionen als auch Polymerisation ab.…”

Evaluation of Enamel Loss with Polycrystalline Ceramic Bracket using two different Debonding Techniques

“…[3][4][5][6] During the course of treatment there is a need of bonding the brackets with bonding agent that will have adequate bond strength between the tooth and bracket so that it will resist force applied to the teeth. [7][8] The term debonding refers to removal of orthodontic attachments and residual adhesive from the enamel surfaces that restore as closely as possible to its pre-treatment condition without inducing iatrogenic enamel damage. 3 During debonding it should be ensured that natural structure of the tooth remains intact or minimal tooth enamel loss shall occur.…”