82 Influence of QAMs on conversion and E-modulus of adhesive resins

Thursday, March 22, 2012: 8 a.m. - 9:30 a.m.
Presentation Type: Oral Session
M. CADENARO1, L. FONTANIVE1, G. MARCHESI1, R. DI LENARDA1, A. TEZVERGIL-MUTLUAY2, F. RUEGGEBERG3, F.R. TAY4, D. PASHLEY4, and L. BRESCHI1, 1Department of Medical Sciences, University of Trieste, Trieste, Italy, 2University of Turku, Turku, Finland, 3Oral Rehabilitation, Georgia Health Sciences University, Augusta, GA, 4Dept. Oral Biology, Georgia Health Sciences University, Augusta, GA

Quaternary ammonium methacrylates (QAMs) are able to inhibit dentin matrix metalloproteinases (MMPs), which contribute to progressive degradation of collagen fibrils in hybrid layers. Thus, the addition of QAMs to adhesive resins has been proposed.

Objectives : The aim of this study was to measure the degree of conversion (DC) and elastic modulus (E) of experimental adhesive blends containing QAMs. The hypothesis tested was that DC and E 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. DC of resin blends was measured by FTIR, while E was measured using a biaxal flexure test. Data were analyzed with a two-way ANOVA and Tukey's post hoc test.

Results: DC was not affected by QAMs' addition (Table 1). A correlation between DC and E could not be found because E varied depending on the type of resin or QAM contained in the blends.

Table 1. Means and standard deviations of DC and E of the tested resin blends.
Resin blend

DC

E

80wt%R2+20wt%ETOH

595a

35951def

80wt%R3+20wt%ETOH

635abc

44740fg

80wt%R5+20wt%ETOH

607ab

32624cde

70wt%R2+20wt%ETOH+10wt%ATA

713abc

36938ef

70wt%R3+20wt%ETOH+10wt%ATA

757c

39927ef

70wt%R5+20wt%ETOH+10wt%ATA

662abc

15121a

70wt%R2+20wt%ETOH+10wt%MCMS

675abc

18329ab

70wt%R3+20wt%ETOH+10wt%MCMS

702abc

53134g

70wt%R5+20wt%ETOH+10wt%MCMS

752bc

23737abc

70wt%R2+20wt%ETOH+10wt%METMAC

643abc

39232ef

70wt%R3+20wt%ETOH+10wt%METMAC

697abc

83361h

70wt%R5+20wt%ETOH+10wt%METMAC

696abc

26025bcd

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

Conclusions: The tested hypothesis was partially accepted since QAMs addition did not affect DC when QAMs were added, while E varied 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).

This abstract is based on research that was funded entirely or partially by an outside source: 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)

Keywords: Adhesion, Polymerization and Polymers