Degree of conversion of resin blends in relation to ethanol content and hydrophilicity

Cadenaro, Milena; Breschi, Lorenzo; Antoniolli, Francesca; Navarra, Chiara O.; Mazzoni, Annalisa; Tay, Franklin R.; Di Lenarda, Roberto; Pashley, David H.

doi:10.1016/j.dental.2008.01.012

« Previous Next »Dental Materials
Volume 24, Issue 9 , Pages 1194-1200, September 2008

Degree of conversion of resin blends in relation to ethanol content and hydrophilicity

Milena Cadenaro
- Department of Biomedicine, Unit of Dental Sciences and Biomaterials, University of Trieste, Via Stuparich 1, I-34125 Trieste, Italy
- Corresponding author. Tel.: +39 040 662744; fax: +39 040 662744.
Lorenzo Breschi
- Department of Biomedicine, Unit of Dental Sciences and Biomaterials, University of Trieste, Via Stuparich 1, I-34125 Trieste, Italy
- IGM-CNR, Unit of Bologna c/o IOR, Bologna, Italy
Francesca Antoniolli
- Department of Biomedicine, Unit of Dental Sciences and Biomaterials, University of Trieste, Via Stuparich 1, I-34125 Trieste, Italy
Chiara O. Navarra
- Department of Biomedicine, Unit of Dental Sciences and Biomaterials, University of Trieste, Via Stuparich 1, I-34125 Trieste, Italy
Annalisa Mazzoni
- Department of SAU & FAL, University of Bologna, Bologna, Italy
Franklin R. Tay
- Department of Oral Biology & Maxillofacial Pathology, School of Dentistry, Medical College of Georgia, Augusta, GA 30912-1129, USA
Roberto Di Lenarda
- Department of Biomedicine, Unit of Dental Sciences and Biomaterials, University of Trieste, Via Stuparich 1, I-34125 Trieste, Italy
David H. Pashley
- Department of Oral Biology & Maxillofacial Pathology, School of Dentistry, Medical College of Georgia, Augusta, GA 30912-1129, USA

Received 13 April 2007; received in revised form 23 January 2008; accepted 29 January 2008.

Abstract

Objectives

To evaluate the degree of conversion of five experimental adhesive systems in relation to their hydrophilicity. The resin blends ranged from hydrophobic to hydrophilic and were tested as neat bonding agents, or solvated with increasing percentages of ethanol. The hypothesis tested was that extent of polymerization of resin blends is affected by resin hydrophilicity, solvent concentrations or time of polymerization.

Methods

Five light-curing versions of neat experimental resin blends were submitted to investigation: (1) 70% E-BisADM, 28.75% TEGDMA; (2) 70% BisGMA, 28.7% TEGDMA; (3) 70% BisGMA, 28.7% HEMA; (4) 40% BisGMA, 30% TCDM, and 28.75% TEGDMA; (5) 40% BisGMA, 30% BisMP, and 28.75% HEMA. All blends included 1% EDMAB and 0.25% CQ. Ethanol in different weight percentages (A: 0%, B: 30%, C: 50%, D: 70% and E: 90%) was added to these resin blends simulating different formulation of adhesives. A differential scanning calorimeter was used to measure the degree of conversion of resin blends as a function of resin hydrophilicity, solvent concentration and time of curing. Data were analyzed with three-way ANOVA and Tukey's post hoc test.

Results

Exotherms showed that degree of conversion was influenced by the hydrophilicity of the blends resin (p<.05), percentage of ethanol dilution (p<.05) and time of curing (p<.05). 30% ethanol dilution increased degree of conversion compared to neat compounds irrespective to resin type and curing time, showing the highest degree of conversion values of the study design.