Final Endodontic Irrigation with 2% Peracetic Acid: Antimicrobial Activity and Cytotoxicity

Abstract

Objective The aim of present study was to assess the cytotoxicity and antimicrobial efficacy of 2% peracetic acid (PAA) compared with 5.25% sodium hypochlorite (NaOCl) and 2% chlorhexidine (CHX). Material and Methods For the cytotoxicity test, 100 µl of the tested solutions were added in 12 wells with ECV 304 endothelial cells in each group: NaOCl, CHX and PAA, in addition to the control group. Each solution was evaluated after 24 hours of contact in four dilutions: 0.2, 0.1, 0.05 and 0.025 through mitochondrial function using MTT colorimetric assay. In the antimicrobial evaluation, 40 dentin blocks 5 mm in length and 0.2 g in weight were incubated with 400 µl of Enterococcus faecalis suspension for 21 days at 37°C. The contaminated samples were divided into three experimental groups within 5 minutes of contact: NaOCl group, CHX group, PAA group, as well as the positive control group. The specimens received treatment and were transferred to a tube with saline for serial dilution of the solution and seeding for isolation and colony forming unit (CFU) count. Statistical Analysis The results obtained were expressed as mean (A570 nm) ± standard deviation (SD) and in a multiple linear regression model and multiple comparisons conducted. Results The antimicrobial evaluation revealed that the NaOCl and CHX groups showed a statistically significant difference compared with the control group (p < 0.001), while the PAA reduced only the CFU growth. It can be concluded that, among the agents tested, PAA expressed greater cell viability, followed by CHX and NaOCl. However, it did not show greater antimicrobial activity in vitro in the mature biofilm of Enterococcus faecalis.

Research methods assessing sodium hypochlorite cytotoxicity: A scoping review

“…The text results are shown in Table 1 . The methyl-thiazol-tetrazolium (MTT) assay, a tetrazolium salt-based colorimetric test, was the test most commonly used to assess cytotoxicity (55.1 % of the papers) [ [15] , [16] , [17] , 23 ], [ [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] ], [ [41] , [42] , [43] , [44] , [45] , [46] , [47] , [48] , [49] , [50] , [51] , [52] , [53] , [54] , [55] , [56] , [57] , [58] , [59] , [60] , [61] , [62] , [63] , [64] , [65] , [66] , [67] , [68] ]. This assay measures cell viability based on the reduction of tetrazolium salt to water-insoluble formazan crystals by dehydrogenases of mitochondria of living cells [ 69 ].…”

“…Cytotoxicity tests are conducted using primary cell cultures [ 22 , 24 , 38 , 43 , 44 , 47 , 49 , 54 , 60 , 65 , 67 , [71] , [72] , [73] , 75 , [77] , [78] , [79] , [81] , [82] , [83] , 86 , 100 , 105 , 106 , 108 ], permanent cell lines [ 15 , 17 ], [ 23 , [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] ], [ [39] , [40] , [41] ], [ 45 , 46 , 48 ], [ [51] , [52] , [53] ], [ [55] , [56] , [57] , [58] , [59] ], [ [61] , [62] , [63] , [64] ], [ 68 , 70 , 74 , 85 , 88 , 89 ], [ [93] , …”

“…This is because the cells in culture are more sensitive to the toxicity of a drug than the variety of elements in the periapical tissues, which contain phagocytic cells, and both lymphatic and blood channels that help dilute and transport the drug [ 118 ]. ISO 10993–5:2009 standard recommends diluting the solutions in a culture medium [ 7 ], as reported by the vast majority of papers (60.7 %) [ 22 , 24 ], [ [26] , [27] , [28] ], [ 30 , [32] , [33] , [34] ], [ [37] , [38] , [39] , [40] , [41] ], [ 43 , 44 , [46] , [47] , [48] ], [ 50 , 53 , [55] , [56] , [57] ], [ 59 , 60 , 62 , 65 , 66 ], [ [70] , [71] , [72] , [73] , [74] ], [ 77 , 78 ], [ [82] , [83] , [84] ], [ 86 , [88] , [89] , [90] , [91] ], [ [94] , [95] , [96] , [97] , [98] , [99] , [100] , [101] , [102] , 115 ], as seen in Table 3 . However, the use of a culture medium or even phosphate-buffered saline (PBS), both of which contain buffering substances, may modify the pH of irrigants, e.g., the pH of NaOCl (>11.0) is reduced to 7.5–8.0 [ 15 ...…”

“…Another aspect to be considered is the effect of fetal bovine serum (FBS) on the cytotoxicity of certain materials. Although the cytotoxicity of dental materials is assessed in the presence of FBS [ [22] , [23] , [24] , 27 , 28 , [32] , [33] , [34] , 41 , 50 , 57 , 59 , 60 , 65 , 71 , 73 , 77 , 83 , 86 , 89 , 94 , 95 , 99 , 100 , 115 ], as observed in 25.8 % of the papers ( Table 3 ), this reagent could alter the results. It has been shown that the presence of FBS in the culture medium decreases the cytotoxicity of chlorhexidine, hydrogen peroxide and NaOCl.…”

Effect of Different Treatment Regimen and Types of Endodontic Sealers on Pain and Periapical Radiographic Changes

“…Pain can be provoked by mechanical, chemical, or microbiological injuries to periodontal tissues [2]. The presence of post-operative pain has been shown to be associated with a number of treatment parameter, the number of visits [3], [4], the choice of root canal sealer [5], the choice of instrumentation [6], [7], [8], [9], [10], including working length (WL) estimation [11], [12], [13].…”