Fernanda Otaviano Martins

Evaluation of the cytotoxicity of latex and non‐latex orthodontic separating elastics

OBJECTIVE To test the hypothesis that a difference in cytotoxicity exists between latex and non-latex orthodontic separating elastics. MATERIAL AND METHODS Five intra-oral separating elastics from different manufactures (four latex and one non-latex) were divided into five groups of 15 elastics each: Group MA (non-latex elastics, Masel), Group MO (natural latex, Morelli), Group DE (natural latex, Dentaurum), Group TP (natural latex, TP Orthodontics) and Group UN (natural latex, Unitek). The cytotoxicity assay was performed using cell cultures (epithelial HEp-2 cells originating from human laryngeal carcinoma) that were submitted to the cell viability test with neutral red (dye-uptake) at 24, 48, 72 and 168 h. Analysis of variance (anova) with multiple comparisons and Tukeys test were employed (p < 0.05). RESULTS The results showed no statistically significant differences between groups MA, DE, TP and UN in relation to Group CC (cell control) for experimental times of 24, 48 and 168 h (p > 0.05). Morelli, Dentaurum, TP Orthodontics and Unitek elastics induced a great amount of cell lyses at 72 h. CONCLUSION One can demonstrate that the Masel elastic induced less cell lysis compared with other elastics, but all trademarks were found to be clinically biocompatible. CLINICAL RELEVANCE Separating orthodontic elastics are used in the interdental subgingival region with the aim to separate the teeth for placement of orthodontic bands. However, latex has been known to cause allergy. As these materials are widely used in clinical orthodontics, care regarding the cytotoxicity of orthodontic elastics should be taken. Thus, clinically proven biocompatible materials should be acquired whenever possible.

Evaluation of cytotoxicity and degree of conversion of glass ionomer cements reinforced with resin

The objective of the present study was to evaluate the cytotoxicity and degree of monomer conversion of resin-reinforced glass ionomer cements (RGIC) over different time periods. Four RGICs: Fuji Ortho LC (FOLC), Fuji Ortho Band (FOB), Orthoglass (OGL), and Multicure Glass Ionomer (MCI) were evaluated for cytotoxicity in fibroblastic L929 cells and for their degree of monomer conversion over different time periods. Three control groups were also analysed: positive control (C+), consisting of Tween 80 cell detergent; negative control (C-), consisting of phosphate-buffered saline; and cell control (CC), consisting of cells exposed to any material. To evaluate the cytotoxicity, the dye-uptake technique was used and the degree of conversion was evaluated using infrared spectroscopy. The data obtained were analysed by analysis of variance and the Tukeys test. The results showed cytotoxicity of the RGICs at 1 and 24 hours; the viability values of these materials were statistically different from the C- and CC groups (P < 0.05). After 48 hours, the FOLC group was statistically similar to the CC and C- groups but different from the others. At 1 hour, there was no difference in the degree of conversion between the FOLC and OGL groups (P > 0.05) or between the FOB and MCI (P < 0.05) groups. However, at 48 hours, the FOLC group had greater conversion values than the other groups (P < 0.05). There is a direct relationship between the degree of conversion and RGIC cytotoxicity. Following initial polymerization, cytotoxicity decreases and, consequently, the degree of conversion of the material increases.

Antiviral activity of the green marine alga Ulva fasciata on the replication of human metapneumovirus

We evaluated the antiviral activity of the marine alga, Ulva fasciata, collected from Rasa beach and Forno beach, Búzios, Rio de Janeiro, Brazil on the replication of human metapneumovirus (HMPV). The algae extracts were prepared using three different methodologies to compare the activity of different groups of chemical composites obtained through these different methodologies. Four out of the six extracts inhibited nearly 100% of viral replication. The results demonstrated that the majority of the extracts (five out of six) possess virucidal activity and therefore have the ability to interact with the extracellular viral particles and prevent the infection. On the other hand, only two extracts (from Forno beach, obtained by maceration and maceration of the decoction) were able to interact with cell receptors, hindering the viral entry. Finally, only the extract of algae collected at Forno beach, obtained by maceration presented intracellular activity. To our knowledge, this is a pioneer study on antiviral activity of marine algae against HMPV. It is also the first on antiviral activity against HMPV ever done in Brazil. The study also shows the effect of different environment factors and different chemical procedures used to obtain the extract on its biological properties.

Impact of low-intensity laser on the suppression of infections caused by Herpes simplex viruses 1 and 2: in vitro study

The use of low-level laser to suppress infections caused by Herpes simplex viruses 1 and 2 was evaluated after one to five applications. A gradual reduction in replication of Herpes simplex viruses 1 and 2 was observed, with 68.4% and 57.3% inhibition, respectively, after five applications, thus favoring its clinical use.

Citotoxicidade de soldas elétricas a ponto: estudo in vitro

Objective: The welding process involves metal ions capable of causing cell lysis. In view of this fact, the aim of this study was to test the hypothesis that cytotoxicity is present in different types of alloys (CrNi, TMA, NiTi) commonly used in orthodontic practice when these alloys are subjected to electric spot welding. Methods: Three types of alloys were evaluated in this study. Thirty-six test specimens were fabricated, 6 for each wire combination, and divided into 6 groups: Group SS (stainless steel), Group ST (steel with TMA), Group SN (steel with NiTi), Group TT (TMA with TMA), Group TN group (TMA with NiTi) and Group NN (NiTi with NiTi). All groups were subjected to spot welding and assessed in terms of their potential cytotoxicity to oral tissues. The specimens were first cleaned with isopropyl alcohol and sterilized with ultraviolet light (UV). A cytotoxicity assay was performed using cultured cells (strain L929, mouse fibroblast cells), which were tested for viable cells in neutral red dye-uptake over 24 hours. Analysis of variance and multiple comparison (ANOVA), as well as Tukey test were employed (p 0.05). Cell viability was higher in the TT group, followed by groups ST, TN, SS, NS and NN. Conclusions: It became evident that the welding of NiTi alloy wires caused a greater amount of cell lysis. Electric spot welding was found to cause little cell lysis.

Cytotoxicity of orthodontic elastic chain bands after sterilization by different methods

Abstract Introduction The aim was to verify the hypothesis that orthodontic elastics in chain form become more cytotoxic after the sterilization process. Materials and methods Orthodontic elastic in chain form with six links each was divided into eight groups according to the sterilization method to be performed. The following groups were formed: Control, alcohol 70, autoclave, glutaraldehyde, microwave, ultraviolet, ethylene oxide and gamma rays. Three additional groups were used, cell control, positive control consisting of cellular detergent Tween 80, and negative control consisting of phosphate buffer solution (PBS). After this, the elastics were immersed in culture media for 24 h to release possible toxic substances. After this period elapsed, the medium was placed in contact with L929 cells for 24 h. Next, the cells were stained and analyzed in a spectrophotometer with regard to their cell viability. The data obtained were analyzed by the analysis of variance (ANOVA) and the Tukeys test. Results The groups of elastic sterilized by chemical means (alcohol 70 and glutaraldehyde) and thermal means (autoclave and microwave) led to an increase in cytotoxicity of the studied elastics, presenting statistically significant differences from the groups sterilized with ethylene, ultraviolet and gamma rays (p < 0.05). Conclusion The hypothesis was partly confirmed, since some of the sterilization methods increased the cytotoxicity of the elastics and others did not.

Atividade antiviral de Musa acuminata Colla, Musaceae

O presente trabalho avalia a atividade antiviral de extratos e fracoes de Musa acuminata Colla, Musaceae, coletada em duas regioes do Estado do Rio de Janeiro (Petropolis e Santo Antonio de Padua). As inflorescencias de M. acuminata apresentaram excelente atividade para os dois virus avaliados: herpesvirus simples humano tipo 1 e herpesvirus simples humano tipo 2, ambos resistentes ao Aciclovir. Os resultados indicam que os extratos de M. acuminata testados podem constituir alvo potencial para uso em terapias antivirais.

Cytotoxicity of alginate for orthodontic use

Three different brands of alginate were divided into three groups, namely, Group JCO (Jeltrate Chromatic Ortho), OP (Orthoprint) and CO (Cavex Orthotrace). Three control groups were also included: Group C+ (positive control), consist-ing of detergent Tween 80; Group C- (negative control), consisting of PBS, and Group CC (cell control), consisting of cells not exposed to any material. After manipulating the materials according to the respective manufacturer instruc-tions, samples were made with the use of silicon rings. Then the samples were immersed in Eagle’s minimum essential medium (MEM) for 2 minutes. The supernatants were then removed and brought into direct contact with L929 fibro-blasts. After exposure to the medium, the cells were incubated for 24 hours. Then 100 l of 0.01% neutral red dye were μadded. The cells were incubated again for 3 hours so that the dye could be absorbed. After this 3-hour period, the cells were fixed to perform the viable cell count, using a spectrophotometer (BioTek, Winooski, Vermont, USA) at a wave-length of 492 nm.

Cytotoxicity of carbamide peroxide bleaching gel on L929 cells

Purpose: To test the hypothesis that the higher the concentration of carbamide peroxide, the greater is its cytotoxicity to fibroblast cells. Methods: Three concentrations of carbamide peroxide (10%, 16%, and 22%) used in home bleaching techniques were evaluated regarding their cytotoxic effect on gingival tissues. The materials were divided into three groups as follows: Group C10 (White Gold Home 10%, Dentsply), Group C16 (White Gold Home 16%, Dentsply, and Group C22 (Nite White 22%, ACP Discus Dental). The cytotoxicity essay was carried out using cell cultures (mouse fibroblast L929 cell line) in which the viable cells were determined by means of the dye-uptake method performed at 2, 4, and 8 hours. Data were analyzed by analysis of variance (ANOVA) with multiple comparisons and Tukey’s test (P < 0.05). Results: The results showed statistically significant differences between Groups C10, C16, C22, and the cell control at 2, 4, and 8 hours (P < 0.05). The amount of cell lysis increased proportionally to the exposure time to the materials studied. Conclusion: The 22% carbamide peroxide group was more toxic than the other two groups (16% and 10% concentration) regardless of the exposure time.

Cytotoxicity of Dental Alginates

Purpose: To evaluate the cytotoxicity of dental alginate (irreversible hydrocolloid), which is widely used as an impression material in Dentistry. Methods: Four dental products were assessed: J (Jeltrate Traditional), ALG (Alga Gel), PG (Printer Gel), and AVG (Ava Gel). Three control groups were used: positive (C+) cell detergent Tween 80, negative (C–) PBS, and control of cells (CC – no exposure of cells to any substance). Disk-shaped specimens were immersed in Eagle minimum essential. The supernatants were collected after 24, 48, 72, and 168 hours (7 days) for analysis of the toxicity to L929 fibroblast cells after 24-h incubation. Viable cells stained with 0.01% neutral red dye were counted using a spectrophotometer. Data were analyzed by ANOVA and Tukey’s test (α=0.05). Results: Significant differences in number of viable cells were found between the alginate groups and C– or CC (P < 0.05). The group J showed the highest cytotoxicity level followed by PG, ALG, and AVG. Conclusion: All dental alginates tested showed some cytotoxic response from fibroblasts.