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

59±5a

359±51def

80wt%R3+20wt%ETOH

63±5abc

447±40fg

80wt%R5+20wt%ETOH

60±7ab

326±24cde

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

71±3abc

369±38ef

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

75±7c

399±27ef

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

66±2abc

151±21a

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

67±5abc

183±29ab

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

70±2abc

531±34g

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

75±2bc

237±37abc

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

64±3abc

392±32ef

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

69±7abc

833±61h

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

69±6abc

260±25bcd

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