Biocompatibility of five synthesized dental monomers

Objectives: To study the cytotoxicity of five novel, synthesized dental monomers.  

Methods: Five functional dental monomers have been synthesized: self-etching acid monomer (M-1), chelating dimethacrylate monomer (M-2), antibacterial monomer (M-3), fluoride-exchange monomer (M-4), and antibacterial fluoride-exchange monomer (M-5). BisGMA was included as control.  Human gingival fibroblasts were obtained from extracted molars from patients with healthy gingiva following informed consent as prescribed in an approved IRB protocol.  Gingival fibroblasts were maintained in MEMα containing 10% fetal calf serum (FCS) and 200 units/ml penicillin and 200 μg/ml streptomycin.  Cells were grown in 48-well plates for 24 hours prior to exposure to the monomers.  The growth media containing 0.1%DMSO were supplemented with 10^-4M, 10^-5M, 10^-6M, and 10^-7M of five synthesized monomers were added to cells for 24hrs.  BisGMA served as a positive control for cytotoxicity.  Cell survival was visualized using a fluorescent esterase substrate (Calcein-AM) and a Nikon TE2000 inverted fluorescent microscope.  Cell survival was quantified using a BioTek Synergy 2 fluorescent multi-well plate reader.  The data were analyzed using ANOVA and Tukey post hoc tests.

Results:

Monomers M-1, M-2 and M-4 show little to no detectable cytotoxicity, with cell retaining their normal, elongated morphology.  M-5 has a cytotoxicity similar to BisGMA (p>0.05).  M-3 was slightly cytotoxic, but significantly less than BisGMA (p<0.05).  

Survival rate of fibroblast cells under different monomers (%) (Mean ±SD)

	Monomers
Concentration	M-1	M-2	M-3	M-4	M-5	BisGMA
0% (Control)	100±17	100±5	100±12	100±7	100±8	100±9
0.5% DMSO	87±17	108±12	92±17	99±16	102±11	103±13
10-7	78±19	105±18	107±17	103±5	107±11	104±10
10-6	74±21	98±16	105±20	103±11	99±14	102±9
10-5	97±9	99±10	99±9	98±11	96±4	96±10
10-4	99±13	93±9	37±14	76±7	11±1	13±2

Conclusions:  All of the synthesized monomers are acceptable for dental applications.  In general, those monomers designed to be antibacterial displayed greater cytotoxicity.  Supported by NIH/NIDCR grant 5R01DE019203-3.