Cytotoxic effects of different concentrations of a carbamide peroxide bleaching gel on odontoblast‐like cells MDPC‐23

Abstract

This study evaluated the cytotoxic effects of a carbamide peroxide (CP) bleaching gel at different concentrations on odontoblast-like cells. Immortalized cells of the MDPC-23 cell line (30,000 cells/cm(2)) were incubated for 48 h. The bleaching gel was diluted in DMEM culture medium originating extracts with different CP concentrations. The amount (microg/mL) of hydrogen peroxide (H(2)O(2)) released from each extract was measured by the leukocrystal violet/horseradish peroxidase enzyme assay. Five groups (n = 10) were formed according to the CP concentration in the extracts: G1-DMEM (control); G2-0.0001% CP (0.025 microg/mL H(2)O(2)); G3-0.001% CP (0.43 microg/mL H(2)O(2)); G4-0.01% CP (2.21 microg/mL H(2)O(2)); and G5-0.1% CP (29.74 microg/mL H(2)O(2)). MDPC-23 cells were exposed to the bleaching gel extracts for 60 min and cell metabolism was evaluated by the MTT assay. Data were analyzed statistically by one-way ANOVA and Tukey's test (alpha = 0.05). Cell morphology was examined by scanning electron microscopy. The percentages of viable cells were as follows: G1, 100%; G2, 89.41%; G3, 82.4%; G4, 61.5%; and G5, 23.0%. G2 and G3 did not differ significantly (p > 0.05) from G1. The most severe cytotoxic effects were observed in G3 and G4. In conclusion, even at low concentrations, the CP gel extracts presented cytotoxic effects. This cytotoxicity was dose-dependent, and the 0.1% CP concentration caused the most intense cytopathic effects to the MDPC-23 cells.

Effect of low-level laser therapy on odontoblast-like cells exposed to bleaching agent

“…Cell culture, bleaching exposure, and LLL irradiation Immortalized cells of the MDPC-23 cell line [21,22] [6,8]. This concentration of bleaching agent was chosen based on previous studies, and represents the amount of hydrogen peroxide that diffuses through enamel and dentin and reaches the pulp chamber after the bleaching procedures [23].…”

“…In each group, ten wells were used to analyze cell metabolism by the cytochemical demonstration of succinic dehydrogenase production, measuring the mitochondrial respiration of the cells by the methyl tetrazolium (MTT) assay, as described in several studies [6,7,[14][15][16]25].…”

“…Due to the deleterious effects caused by components of bleaching agents, which have been demonstrated in both in vitro [6][7][8][9][10] and in vivo studies [3,5,11], the evaluation of other bleaching techniques that can prevent or reduce pulp damage is needed. Thus, laser is promising coadjutant treatment that can be used in the photodynamic therapy [12,13], stimulate cell differentiation, reduction of inflammation, and tissue repair [14][15][16][17].…”

“…The bio-stimulatory effects of LLLT on pulp cells such as odontoblasts are important, since these cells are responsible for dentin matrix deposition and its mineralization. In addition, odontoblasts are the first pulp cells to be reached by products released from dental materials capable of diffusing through enamel/dentin [6,7]. In this way, it may be suggested that the low-level laser irradiation of odontoblasts, prior to or immediately after toothbleaching therapies, may prevent pulp damage or improve the pulpal healing caused by ROS or other sub-products released from bleaching agents.…”

Effects of 405 nm Diode Laser on Titanium Oxide Bleaching Activation

“…Most current office bleaching products employ high concentration H 2 O 2 to produce higher amounts of free radicals. 11 However, a number of safety issues have been raised regarding the effects of bleaching on the tooth structure, 12,13 pulp tissues, [14][15][16][17] and the mucosal tissues of the mouth, as well as systemic ingestion. 1 High concentration H 2 O 2 irritates soft tissue; therefore, these products require strict isolation of the teeth.…”