Effect of various polymerization protocols on the cytotoxicity of conventional and self-adhesive resin-based luting cements

Abstract

OBJECTIVES This study evaluated the cytotoxicity of resin-based luting cements on fibroblast cells using different polymerization protocols. MATERIALS AND METHODS Two conventional dual-polymerized (RelyX ARC, VariolinkN) and two self-adhesive resin cements (RelyX Unicem, Multilink Speed) specimens were polymerized using four different polymerization protocols: (a) photopolymerization with direct light application, (b) photo-polymerization over ceramic and (c) resin nanoceramic discs and (d) auto-polymerization. The specimens were then assigned to four groups to test cytotoxicity at 0, 1, 2 and 7 preincubation days (n = 5). MTT test was performed using NIH/3T3 fibroblast cells. Data were analysed using three-and one-way ANOVA. Multiple comparisons were made using Bonferroni post hoc test (p < 0.05). RESULTS The highest cytotoxic values were recorded at day 2 for conventional resin cements and at day 0 for self-adhesive resin cements. Self-adhesive resin cements showed the most cytotoxic effect at the second day, while conventional resin cements presented immediate cytotoxicity. Auto-polymerized resin specimens and especially Multilink Speed demonstrated the most cytotoxic effect regardless of the preincubation time. Cytotoxicity of cements tested reached the lowest level at day 7. Interposition of ceramic or nano-ceramic restorative material did not significantly affect the cytotoxicity of tested luting cements (p > 0.05). CONCLUSIONS Cytotoxicity of dual-polymerized resin cements was material-dependent and decreased gradually up to 7 days. Photo-polymerization plays an important role in reducing the cytotoxic effects. CLINICAL RELEVANCE When luting ceramic or resin nano-ceramic restorations of which thickness does not exceed 2 mm, the level of cytotoxicity with the tested materials is not significant. Luting of restorative materials that do not allow for light transmission such as metal-fused porcelain, clinicians should be cautious in the use of dual-polymerized conventional resin cements as only auto-polymerization of resin cements takes place under such materials.

Influence of the degree of conversion and Bis-GMA residues of bulk fill resins on tissue toxicity in an subcutaneous model in rats

“…26 Adequate light curing dramatically attenuates cell damage induced by monomers. 30 Therefore, despite the BF resins allowing application in a single increment, 20 there is a gradual decrease in DC in the deeper layers of the material, 31 thus we suggest caution in the use of BF resin with a large concentration of bis-GMA in very deep cavities (>2 mm). UDMA and TEGDMA are also cytotoxic, 22,24 however, light curing of the composite with higher UDMA content (Tetric N-Ceram, Filtek Z-350, Tetric N-Ceram Bulk Fill, Filtek Bulk Fill One) led to fewer monomer residues and toxicity.…”

In vitro cytotoxicity of different dental resin-cements on human cell lines

“…Adhesive luting cements are increasingly used in modern dentistry, as they are the means of choice for cementing ceramic restorations, have good mechanical properties, and are very easy to handle using automix application systems [30]. Nevertheless, various studies have investigated the cytotoxicity of resin-based dental materials on different (human) cell lines [31][32][33][34][35][36][37]. In addition, also cytotoxic effects of different resin luting cements on dental pulp and odontoblastic cells have been elucidated [38,39].…”

Biocompatibility assessment of resin-based cements on vascularized dentin/pulp tissue-engineered analogues

“…Research has shown that an inflammatory effect, combined with disorganization of the odontoblastic layer is evident a week after the application of resin cements, and this effect may persist even for two months later in vivo [13]. Likewise, it has been shown in a 2D in vitro experiment, that the cytotoxic effect is exerted as soon as the material comes in contact with the cells and gradually weakens off by the seventh day [14]. This implies that there is a discrepancy between the in vitro and in vivo results.…”