Evaluation of Cell Responses Towards DMSO- solvated Adhesives

Objectives:
To evaluate transdentinal cytotoxicity and eluates cytotoxicity of hydrophobic and hydrophilic methacrylate-based resins containing various concentrations of dimethyl sulfoxide (DMSO).
Methods:
Hydrophobic resin (R2: 70% BisGMA, 28,75% TEGDMA, 0,25% CQ, 1% EDMAB), and hydrophilic (R5: 40% BisGMA, 28,75% HEMA, 30% 2MP, 0,25% CQ) were incorporated into DMSO (0, 0.01, 0.1, 1, 5, 10 w/w %).
In vitro dentin barrier test was performed using 3-D cultures of odontoblast-like cells (SV40 transfected pulp derived cells) with dentin slices of 400 µm thickness (n=8/experimental group). After 24 h incubation at 37°C, dentin surfaces were acid-etched with phosphoric acid, then DMSO- modified resins were applied into the cavity part of the device for 10 s and light cured for 10 sec. Cell viability after exposure to the bonding agents was assessed by MTT test, and spectrometrically analyzed.
Moreover, resin discs (n=10/group) (0.5mm thick, 6mm diameter) were prepared from each DMSO-solvated R2 or R5 and light-cured (Elipar, 3M ESPE, Seefeld, Germany) for 20 s. After standardization and calibration, human gingival fibroblasts (HGF-1) were exposed to eluates for 24 hrs. Cell viability was assessed by MTT test, and spectrometrically analyzed. Data of both tests were statistically analyzed by ANOVA and Tukey test (α=0.05).

Results: In dentin barrier test, incorporation of DMSO into R2 did not significantly decrease the percentage (%) of cell viability (p>0.05). Incorporation of 1-10 w/w % DMSO into R5 significantly reduced the % of cell viability (p<0.05). Results of resin eluates showed significant reduction in the % of cell viability among all DMSO- R2 or R5, compared to negative control (p<0.05). Also, DMSO-R5 showed significant reduction in the % of cell viability, compared to DMSO-R2.
Conclusions: Incorporation of DMSO into hydrophilic methacrylate resins may increse the transdentinal cytotoxicity and eluates cytotoxicity. The biocmpatibility is not influenced by the addition of DMSO into hydrophobic methacrylate resin.