Effect of 4-(N,N-dimethylamino)phenethyl Alcohol on Degree of Conversion and Cytotoxicity of Photo-Polymerized CQ-Based Resin Composites

Abstract

The aim of this study was to evaluate the degree of conversion (DC) and the cytotoxicity of photo-cured experimental resin composites containing 4-(N,N-dimethylamino)phenethyl alcohol (DMPOH) combined to the camphorquinone (CQ) compared with ethylamine benzoate (EDAB). The resin composites were mechanically blended using 35 wt% of an organic matrix and 65 wt% of filler loading. To this matrix was added 0.2 wt% of CQ and 0.2 wt% of one of the reducing agents tested. 5x1 mm samples (n=5) were previously submitted to DC measurement and then pre-immersed in complete culture medium without 10% (v/v) bovine serum for 1 h or 24 h at 37 °C in a humidifier incubator with 5% CO2 and 95% humidity to evaluate the cytotoxic effects of experimental resin composites using the MTT assay on immortalized human keratinocytes cells. As a result of absence of normal distribution, the statistical analysis was performed using the nonparametric Kruskal-Wallis to evaluate the cytotoxicity and one-way analysis of variance to evaluate the DC. For multiple comparisons, cytotoxicity statistical analyses were submitted to Student-Newman-Keuls and DC analysis to Tukey's HSD post-hoc test (=0.05). No significant differences were found between the DC of DMPOH (49.9%) and EDAB (50.7%). 1 h outcomes showed no significant difference of the cell viability between EDAB (99.26%), DMPOH (94.85%) and the control group (100%). After 24 h no significant difference were found between EDAB (48.44%) and DMPOH (38.06%), but significant difference was found compared with the control group (p>0.05). DMPOH presented similar DC and cytotoxicity compared with EDAB when associated with CQ.

Influence of Different Concentration and Ratio of a Photoinitiator System on the Properties of Experimental Resin Composites

“…This mismatch becomes even more pronounced if bleaching is performed in those restored teeth (7). Moreover, due to the tendency for internal discoloration of the resin composite, the amount of the tertiary amine may be a concern, since these amines have double bonds, which are capable of absorbing UV light and react with oxygen or other aromatic groups, causing the yellowing of the material (8). According to Musanje et al (4), higher quantities of CQ promote a rapid generation of large amounts of free radicals, but this may result in a reduced ability to form an adequate polymer network, since polymers with relatively lower molecular weight are formed.…”

Influence of Photoinitiator and Light-Curing Source on Bond Strength of Experimental Resin Cements to Dentin

“…Another major problem is that the α-diketone group derived from CQ, has peak absorption in the visible range (468 nm) (12), resulting in fast photopolymerization under ambient light (fluorescent lamps and dental lamps) and a short operation time (1). It is the reason why researchers have tested different photoinitiators in the organic matrix to substitute or act synergistically with CQ (7)(8)(9)(10).…”

The effect of 4,4'-bis(N,N-diethylamino) benzophenone on the degree of conversion in liquid photopolymer for dental 3D printing

“… 8 Currently, a binary photoinitiating system, such as a camphorquinone (CQ)-amine complex, is the most widely used among commercial light-cured packable dental resins. 13 14 However, CQ is inherently yellow, so the shade may cause esthetic problems in the anterior teeth. 9 14 15 On top of that, its inner shielding effect and poor solubility in water have been noted as other drawbacks of CQ.…”