Effect of composite surface treatment and aging on the bond strength between a core build-up composite and a luting agent

Abstract

Objective The purpose of this study was to assess the influence of conditioning methods and thermocycling on the bond strength between composite core and resin cement.Material and Methods Eighty blocks (8×8×4 mm) were prepared with core build-up composite. The cementation surface was roughened with 120-grit carbide paper and the blocks were thermocycled (5,000 cycles, between 5°C and 55°C, with a 30 s dwell time in each bath). A layer of temporary luting agent was applied. After 24 h, the layer was removed, and the blocks were divided into five groups, according to surface treatment: (NT) No treatment (control); (SP) Grinding with 120-grit carbide paper; (AC) Etching with 37% phosphoric acid; (SC) Sandblasting with 30 mm SiO2 particles, silane application; (AO) Sandblasting with 50 mm Al2O3 particles, silane application. Two composite blocks were cemented to each other (n=8) and sectioned into sticks. Half of the specimens from each block were immediately tested for microtensile bond strength (µTBS), while the other half was subjected to storage for 6 months, thermocycling (12,000 cycles, between 5°C and 55°C, with a dwell time of 30 s in each bath) and µTBS test in a mechanical testing machine. Bond strength data were analyzed by repeated measures two-way ANOVA and Tukey test (α=0.05).Results The µTBS was significantly affected by surface treatment (p=0.007) and thermocycling (p=0.000). Before aging, the SP group presented higher bond strength when compared to NT and AC groups, whereas all the other groups were statistically similar. After aging, all the groups were statistically similar. SP submitted to thermocycling showed lower bond strength than SP without thermocycling.Conclusion Core composites should be roughened with a diamond bur before the luting process. Thermocycling tends to reduce the bond strength between composite and resin cement.

Grinding of composite cores using diamond burs with different grit sizes

“…Bonstein et al 39 suggested that surface treatment with only a diamond bur on aged composites is simple, efficient, and does not require additional dental materials or instrumentation. Other methods of surface roughening were tested, including sandpapers 7,24,40 , abrasive stone 11 , and pumice 41 , but for these studies the increased bonding is associated with surface grinding, followed by the application of a primer/adhesive. We chose to test burs for their finishing abilities (i.e., surface treatments) because the method is simple, has low cost and is available in the dental office.…”

“…Thus, some studies have proposed that the surface treatment of aged resins could increase their adhesions to fresh resins. Some of these techniques include: grinding with a diamond bur [14][15][16] or with a diamond bur followed by acid etch/adhesive 11,17,18 , lasers irradiation [19][20][21][22][23] , air abrasion with aluminum oxide particles and silanization 15,16,18,24 , air abrasion with silica-coated alumina particles and silanization 14,15,24,25 , and treatment with hydrofluoric acid 18,[26][27][28] . However, some of these techniques (e.g., air-abrasion and laser) require extra armamentarium in the clinical setting.…”

“…However, some of these techniques (e.g., air-abrasion and laser) require extra armamentarium in the clinical setting. As a result, the cost of the treatment increases 29 , a rubber dam is required to avoid damage to the patient's periodontium and inhalation of particles 24 , and materials that are potentially unsafe (e.g., silica particles and hydrofluoric acid can be corrosive and toxic) are used intra-orally.…”

Effect of different surface treatments and retainer designs on the retention of posterior Pd-Ag porcelain-fused-to-metal resin-bonded fixed partial dentures

“…The retainers that debonded from each RBFPD during the peak RR force were recorded and counted. The methods employed in all parts of the present study were designed according to the results of previous studies ( 5 , 29 – 32 ).…”

Deproteinization stabilises dentin bonding of self-adhesive resin cements after thermocycling

“…The resin blocks were light activated for 80 s (40 s per side) with LED dental curing unit (DB -685; Dabi Atlante Ribeirão Preto/SP, Brazil). The restoration surface in contact with the dentin was roughened with a diamond point 30 mm (FG 3098F, KG Sorensen, Cotia, SP, Brazil) [22,23], and then submitted to an ultrasonic bath in distilled water for 10 min. Before the cementation, the internal surface was silanized (Prosil, FGM, Joinville, SC, Brazil) following manufacturer´s instructions.…”