New Antibacterial Monomers’ Effect on a Commercial Dental Adhesive’s Conversion.

Objectives: The aim of this study was to investigate the degree of conversion (DC%) and glass transition temperature (Tg) of resin mixtures obtained blending four new antibacterial quaternary ammonium dimethacrylates (QADMs), synthesized in our laboratory (Italian patent n° 102019000020949 11.12.2019), into a 3-steps Etch&Rinse commercial adhesive (Scotch Bond Multipurpose, 3M ESPE; SBMP). The hypothesis was that the adhesive’s conversion was not affected by the QADMs.
Methods: The four patented experimental antibacterial QADMs were added at 1% w/w to SBMP adhesive. DC% of SBMP+1%QADMs mixtures was obtained by Attenuated Total Reflection Fourier Transform Infrared spectroscopy (ATR-FTIR) measurements (N=10) at baseline and after 40s resin photopolymerization (Valo Grand, Ultradent). Ten disks of each photopolymerized resin mixture (SBMP+1%QADMs) were thermally analyzed through Differential Scanning Calorimetry (DSC) and Tg was calculated. Specimens of neat SBMP were used as a control. Groups were statistically compared with the non-parametric Mann-Whitney and Dunn tests (p=0.05).
Results: DC% and Tg of SBMP adhesive were not significantly affected by 1% QADMs (Table 1). In all specimens tested, DC% values were around 74% and Tg was similar to the SBMP baseline (71°C).
Conclusions: The hypothesis was accepted, as DC% and Tg of SBMP+1%QADMs were not significantly different from the control.