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Cross-linking of QAM-based adhesive resins

Dentin matrix metalloproteinases (MMPs), which contribute to progressive degradation of collagen fibrils in hybrid layer, can be inhibited by quaternary ammonium methacrylates (QAMs). Thus, the addition of QAMs to adhesive resins has been proposed.

Objectives : The aim of this study was to measure the cross-linking density (CLD) of experimental adhesive blends containing QAMs. The hypothesis tested was that CLD of resin blends is not affected by QAMs content.

Methods: Light-curing experimental adhesive blends containing 70wt% resin (R2: 70wt% bisGMA, 28.75wt% TEGDMA; R3: 70wt% BisGMA, 28.75wt% HEMA; R4: 40wt% BisGMA, 30wt% TCDM, 28.75wt% TEGDMA; R5: 40wt% BisGMA, 30wt% BisMP, 28.75wt% HEMA), 20wt% ethanol (ETOH) and 10wt% QAMs in their anhydrous form (ATA or MCMS or METMAC) were prepared. All blends included 1wt% EDMAB+0.25wt% CQ. Resins with no QAMS were used as a control (80wt% R2-R5+20wt% ETOH). Resins were photo-polymerized with a halogen curing light for 40s. The crosslink density was estimated by the softening influence of ethanol: Vickers microhardness (VH) was measured on the irradiated specimen side at five locations, and the mean value was calculated. Specimens were then placed in 100% ethanol for 24 h at 37°C, and the hardness was determined again. Data were analyzed with one-way Anova and T-test (a<0.05).

Results: CLD was reduced by QAMs' addition, especially for R4 and R5 (p<0.05) as shown in Table 1.

Table 1. Means and standard deviations of VH of the tested resin blends.

Resin blend

 VH0

 VHETOH
80wt%R2+20wt%ETOH

 3.0±0.3i,j,k

 2.7±0.2h,i
70wt%R2+20wt%ETOH+10wt%ATA

 3.0±0.2i,j,k

 2.5±0.2h
70wt%R2+20wt%ETOH+10wt%MCMS

 2.7±0.2h,i,j

 2.5±0.3h
70wt%R2+20wt%ETOH+10wt%METMAC

 2.2±0.4g

 2.0±0.3g
80wt%R3+20wt%ETOH

 1.5±0.3e,f

 1.1±0.1d
70wt%R3+20wt%ETOH+10wt%ATA

 1.5±0.4f

 1.5±0.2f
70wt%R3+20wt%ETOH+10wt%MCMS

 1.5±0.2e,f

 1.5±0.1f
70wt%R3+20wt%ETOH+10wt%METMAC

 1.6±0.4f

 1.6±0.2f
80wt%R4+20wt%ETOH

 2.1±0.2g

 1.3±0.1d,e,f
70wt%R4+20wt%ETOH+10wt%ATA

 3.0±0.1j,k

 2.1±0.2g
70wt%R4+20wt%ETOH+10wt%MCMS

 4.0±0.2m

 3.0±0.2i,j,k
70wt%R4+20wt%ETOH+10wt%METMAC

 3.1±0.2l

 3.2±0.1l
80wt%R5+20wt%ETOH

 0.8±0.1c

 0.3±0.1a,b
70wt%R5+20wt%ETOH+10wt%ATA

 0.5±0.1a,b,c

 0.4±0.1a,b
70wt%R5+20wt%ETOH+10wt%MCMS

 0.2±0.1a

 0.2±0.1a
70wt%R5+20wt%ETOH+10wt%METMAC

 1.2±0.2d,e

 0.6±0.1b,c

Same superscript letters indicate no statistical difference (p>0.05).

Conclusions: The tested hypothesis was rejected since QAMs addition affected CLD when QAMs were added, varying in relation to resin and QAM type.

Supported, in part, by grants: FIRB RBAP1095CR and PRIN 2009SAN9K5 and 2009FXT3WL from MIUR, Italy, R01DE015306 to DHP (PI), and #8126472 from the Academy of Finland to AT-M (PI).


Division: IADR/LAR General Session
Meeting: 2012 IADR/LAR General Session (Iguaçu Falls, Brazil)
Location: Iguaçu Falls, Brazil
Year: 2012
Final Presentation ID: 1673
Abstract Category|Abstract Category(s): Dental Materials 1: Adhesion - Bond Strength Testing and Mechanisms
Authors
  • Cadenaro, Milena  ( University of Trieste, Trieste, N/A, Italy )
  • Fontanive, Luca  ( University of Trieste, Trieste, N/A, Italy )
  • Di Lenarda, Roberto  ( University of Trieste, Trieste, N/A, Italy )
  • Tezvergil-mutluay, Arzu  ( University of Turku, Turku, N/A, Finland )
  • Scotti, Nicola  ( University of Turin, Turin, N/A, Italy )
  • Tay, Franklin  ( Georgia Health Sciences University, Augusta, GA, USA )
  • Pashley, David  ( Georgia Health Sciences University, Augusta, GA, USA )
  • Breschi, Lorenzo  ( University of Trieste, Trieste, N/A, Italy )
    • SESSION INFORMATION
    Poster Session
    Adhesion, Bond Strength, and Durability II
    06/22/2012