Do Different Tooth Bleaching-Remineralizing Regimens Affect the Bleaching Effectiveness and Enamel Microhardness In Vitro?

Objective: Tooth bleaching may negatively affect the enamel surface properties, such as reduction in hardness values, and remineralizing agents can reverse these effects. This study evaluated the effect of remineralizing agents before, during, and after the bleaching process on enamel's whitening effectiveness and microhardness. Methods and Materials: The initial color of 104 bovine incisors after immersion in tea solution was recorded, and then, the teeth were randomly divided into eight groups (n = 13). Group 1 (NC) was considered the control with no treatment, and Group 2 (B) was bleached with 40% hydrogen peroxide gel. The 3% fluorohydroxyapatite (FHA) and 2% sodium fluoride (NaF) were applied before (FHA/B, NaF/B), during (FHA + B, NaF + B) and after (B/FHA, B/NaF) the bleaching process in other groups. The final color and microhardness in three depths of 20-30, 50-60, and 100-120 µm were measured. Data were analyzed using Shapiro-Wilk, one-way ANOVA, Tukey, Games Howell, repeated measurement, and LSD tests. Results: The FHA + B presented the lowest ΔE, significantly lower than other groups, except B/FHA. The ΔE in B/FHA was significantly lower than B/NaF. The bleaching significantly reduced the enamel hardness in three depths. The highest microhardness values were reported for B/NaF and NaF + B, which have no noticeable difference with NC, while FHA/B showed the lowest hardness in three depths, which was significantly lower than NC. Conclusion: The application of NaF before, during, and after the bleaching improved the microhardness of bleached enamel as the unbleached one with no adverse effect on whitening effectiveness.

In Vitro Study of the Leishmanicidal Activity of Perovskia Abrotanoides Terpenoid-Rich Fractions Against Leishmania Major (MRHO/IR/75/ER).

Background: Cutaneous leishmaniasis (CL) is an ulcerative skin disease caused by some species of the genus Leishmania. Evidence shows that Perovskia abrotanoides is an important herbal medicine against Leishmania. This study was conducted to investigate the killing effect of terpenoid-rich fractions on promastigotes of L. major (MRHO/IR/75/ER). Material and Method: The eluates of reverse phased medium pressure liquid chromatography (RP-MPLC) of the extract were subjected to thin-layer chromatography (TLC) and categorized into six final fractions. Primary proton nuclear magnetic resonance (H-NMR) spectroscopy confirmed fractions' nature. Fractions 4, 5, and 6 (F4, F5, F6) were identified as terpenoid-rich content. Two concentrations of 50 and 100 µg/ml were prepared to test leishmanicidal activity. Followed by treating promastigotes of L. major by the fractions in incubation times of 12, 24, and 48 hours, their viability was determined using a cell proliferation MTS ((3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. Result: F4, F5, and F6 showed significant killing activity on promastigotes of L. major in a concentration-dependent manner. The viability of promastigotes was significantly reduced at a concentration of 100 µg/ml compared to 50 µg/ml (P-value <0.05). Also, over time a significant decreasing trend in the viability of promastigotes confirmed the time-dependent manner of the fractions (P-value <0.01). Furthermore, F5 had the highest leishmanicidal activity at the first incubation time compared with other fractions. Conclusion: Terpenoid-rich fractions of the P. abrotanoides have a leishmanicidal activity that depends on time and concentration. Among them, F5 has the highest potency that may contain potent terpenoid constituents.

In Vitro and In Vivo Anti-Toxoplasma Activities of Dracocephalum kotschyi Extract in Experimental Models of Acute Toxoplasmosis.

BACKGROUND: The problem of resistance to antiparasitic drugs, associated with their side effects, suggest exploring other alternatives, including medicinal plants. Dracocephalum kotschyi (D. kotschyi), for example, from Lamiaceae family, is a plant widely used in Iran and in many countries, and to which interesting pharmacological properties have been attributed. This study aimed to investigate in vitro and in vivo anti-Toxoplasma activities of D. kotschyi extract in experimental models of acute toxoplasmosis. METHODS: Anti-Toxoplasma activity of the extracts in vitro was performed on Vero Cell, using the MTT test. Vero cell were infected with (3 × 105 tachyzoites/well) following treatment with Dichloromethane (F1), dichloromethane: methanol (F2), methanol (F3), methanol: water (F4), and deionized water (F5) extracts of D. kotschyi, and pyrimethamine and sulfadiazine (positive control). MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) was used to measure cell viability. Effects of extracts on tachyzoites viability were evaluated by trypan blue exclusion method, followed by light microscopy. For in vivo test, 18 groups of 8-10-week-old Inbred Balb/c mice weighing 18-20 g, were intraperitoneally infected with 2 × 103 tachyzoites and then treated with sterile PBS (negative control), pyrimethamine (25 mg/kg) and sulfadiazine (500 mg/kg) as positive controls, and F1 to F5 extracts (at doses 50, 100 and 200 mg/kg). RESULTS: The 50% Inhibitory Concentration of F1 extract, F2 extract, Sulfadiazine (Positive control) and Pyrimethamine (Positive control) were 8.77 µg, 7.1 µg 391.18 µg, and 84.20 µg, respectively, while the selectivity indices were 15.667, 30.197, 1.552 and 4.064, respectively. In vivo anti-Toxoplasma activity test showed that Methanol: water (F-4) 50 extract was more active than the positive control. CONCLUSIONS: Indeed, the extract allowed a survival rate of 10% of the mice, compared to 0% for all the other groups. D. kotschyi has the potential to be valorized in the management of toxoplasmosis.

Effect of transgenic Leishmania major expressing mLLO-Bax-Smac fusion gene in the apoptosis of the infected macrophages.

Objectives: Leishmaniasis is a complex infection against which no confirmed vaccine has been reported so far. Transgenic expression of proteins involved in macrophage apoptosis-like BAX through the parasite itself accelerates infected macrophage apoptosis and prevents Leishmania differentiation. So, in the present research, the impact of the transgenic Leishmania major including mLLO-BAX-SMAC proapoptotic proteins was assayed in macrophage apoptosis acceleration. Materials and Methods: The coding sequence mLLO-Bax-Smac was designed and integrated into the pLexyNeo2 plasmid. The designed sequence was inserted under the 18srRNA locus into the L. major genome using homologous recombination. Then, mLLO-BAX-SMAC expression was studied using the Western blot, and the transgenic parasite pathogenesis was investigated compared with wild-type L. major in vitro and also in vivo. Results: Western blot and PCR results approved mLLO-BAX-SMAC expression and proper integration of the mLLO-Bax-Smac fragment under the 18srRNA locus of L. major, respectively. The flow cytometry results revealed faster apoptosis of transgenic Leishmania-infected macrophages compared with wild-type parasite-infected macrophages. Also, the mild lesion with the less parasitic burden of the spleen was observed only in transgenic Leishmania-infected mice. The delayed progression of leishmaniasis was obtained in transgenic strain-injected mice after challenging with wild-type Leishmania. Conclusion: This study recommended transgenic L. major including mLLO-BAX-SMAC construct as a pilot model for providing a protective vaccine against leishmaniasis.

Evaluation of the Anti-Leishmanial Effect of Recombinant Clostridium α-Toxin.

BACKGROUND: Leishmaniasis is an infectious disease common in tropical and subtropical regions caused by the genus Leishmania, which is transmitted by the bite of female sandflies. In this study, we evaluate the anti-leishmanial effect of recombinant Clostridium α-toxin protein alone and the combination with glucantime through in vitro and in vivo. MATERIALS AND METHODS: Production, expression, and purification of recombinant α-toxin were evaluated by SDS-PAGE and Western blotting techniques. The antileishmanial activities of the purified α-toxin plus and without glucantime were examined in vitro and in vivo. RESULTS: The results indicated successful expression of α-toxin as a 48 kDa band on SDS-PAGE and Western blot methods. Also, evaluation of α-toxin IC50 showed the strong fatal effect of it, and glucantime on medium proliferated Leishmania promastigotes at lower concentrations compared with glucantime or α-toxin alone. Moreover, in vivo surveys showed that at the end of treatment courses, the mean of lesion size diminished in glucantime plus α-toxin treated mice versus negative control groups (p < 0.001). Also, there was a significant difference in the parasite burden of the spleen and liver of the control versus the test groups (p < 0.001). CONCLUSION: The results showed recombinant α-toxin has synergistic effects with glucantime in destroying Leishmania parasites.

Color properties of artificial white spot lesions treated by experimental resin infiltrants containing bioactive glass and nano-fluorohydroxyapatite.

AIM: This study was conducted to assess the masking effects of some experimental resin infiltrants containing bioactive glass (BAG) and nano-fluorohydroxyapatite (n-FHAP) on enamel white spot lesions (WSLs). MATERIALS AND METHODS: Fifty enamel specimens were embedded in an acrylic resin and divided into five groups (n = 10). After creating artificial enamel lesions, the specimens were infiltrated by the following resins: 1) Group 1 (T/control group): TEG-DMA; 2) Group 2 (T2H): TEG-DMA + 2 wt% n-FHAP; 3) Group 3 (T5H): TEG-DMA + 5 wt% n-FHAP; Group 4 (T2B): TEG-DMA + 2 wt% BAG; Group 5 (T5B): TEG-DMA + 5 wt% BAG. Next, the specimens were subjected to demineralization-remineralization cycles for 2 weeks. Color assessments were performed by a spectrophotometer in four distinct stages: baseline, after the production of artificial caries, after resin infiltration, and 2 weeks after resin infiltration. L*, a*, b*, and ΔE values were calculated at each stage. Color parameters were analyzed statistically using the Kruskal-Wallis and Mann-Whitney U tests. The significance level was set at 5%. RESULTS: All treatments led to a decrease in the L3* compared with the L2* value. The resin infiltrant containing 5% fluorohydroxyapatite (FHAP) exerted the highest L* reduction effect among all the groups. The T group was the only resin infiltrant group with a lower mean of a4* than those compared at baseline. Regarding the ΔE13* and ΔE14* values, only the resin infiltrants of groups 1 (T), 2 (T2H), and 3 (T5H) were able to mask artificial caries. CONCLUSION: Experimental resin infiltrants containing n-FHAP were able to mask WSLs after 14 days.

Study of therapeutic effect of different concentrations of imatinib on Balb/c model of cutaneous leishmaniasis.

Leishmaniasis, as a tropical and subtropical disease, is endemic in more than 90 countries around the world. Today, cutaneous leishmaniasis (CL) that affects more than 1.5 million people per year lacks a definitive treatment approach. Imatinib is an anticancer drug that inhibits the abnormal function of Bcr-Abl due to its tyrosine kinase inhibitor, and that was the reason why the drug was tested for CL treatment because protein kinases are essential enzymes in the Leishmania genus. In this study, the L. major CL model of Balb/c mice was produced by injection of the cultured metacyclic form of parasite at the base of the tail. The possible recovery of CL ulcers and determination of the optimum dose of imatinib against Leishmania amastigotes were evaluated. A significant decrease was observed in mice treated with amphotericin B (positive control group) as well as imatinib 50 mg/kg compared to the unreceived drug, negative control group (P<0.05). This study could be promising in gaining insight into the potential of imatinib as an effective treatment approach against CL.

Frequency and Molecular Identification of Cryptosporidium Species among Immunocompromised Patients Referred to Hospitals, Central Iran, 2015-16.

BACKGROUND: The purpose of this study was to determine the prevalence and genotype of Cryptosporidium spp. in different groups of immunocompromised patients admitted to the referral hospitals in center of Iran during 2015-2016. METHODS: This cross-sectional study was conducted on 346 immunocompromised patients (HIV+/AIDS, Lymphoma, Leukemia and organ transplants) in referred hospitals from central parts of Iran including Isfahan, Markazi, Yazd and Chaharmahale Bakhtiari provinces. Stool samples were analyzed for Cryptosporidium species, modified Ziehl-Neelsen staining techniques followed by the semi-nested PCR and DNA sequencing methods. RESULTS: The total rate of Cryptosporidium spp. was 3.46% (12/346) in the patients, however, the prevalence of the parasite, was 4.6% (4/87) in HIV+/AIDS patients, 3.6% (6/168) in patients with blood malignancy and 2.1% (2/91) in organ transplant recipients. The SSU rRNA gene of Cryptosporidium spp. in all microscopic-positive samples was effectively amplified by the semi-nested PCR and DNA sequences, exposed the existence of two Cryptosporidium species, including C. hominis 91.6% (11/12) and C. parvum 8.3% (1/12). CONCLUSION: The predominance of C. hominis in the present study may be certifies the importance of anthroponotic transmission of cryptosporidiosis in center of Iran.

Evaluation of Different Concentrations of Imatinib on the Viability of Leishmania major: An In Vitro Study.

BACKGROUND: Leishmaniasis is an infectious disease caused by an intracellular parasite of Leishmania and is transmitted through the female sandflies bite and may lead to severe skin lesions. Although drugs such as antimony compounds are available, their side effects such as toxicity, low efficacy, and emergence of resistance have raised the importance of effective replacement. Imatinib, as an inhibitor of tyrosine kinase (TK) of Leishmania, stops abnormal function of TK such as Bcr-Abl through assembling into transmembrane pores in a sterol-dependent manner. Hence, the evaluation of killing effects of different concentrations of imatinib against Leishmania major amastigotes and promastigotes in vitro were the objectives of the present study. MATERIALS AND METHODS: The killing effects of different concentrations of imatinib (25, 50, and 100 µg) and 25 µg amphotericin B (as positive control) were evaluated against RPMI 1640-cultured promastigotes and the amastigote/macrophage model by MTS cell proliferation assay kit (ab197010) and Giemsa staining method during 24, 48, and 72 h. RESULTS: The results showed anti-Leishmania effect of imatinib in concentration and time-dependent manner. The lowest number of live promastigotes and amastigotes were obtained due to treat with 100 µg/ml imatinib at 72 h. Furthermore, 100 µg concentration of imatinib had the same effect as 25 µg amphotericin B on both L. major promastigotes and amastigotes (P < 0.001). CONCLUSION: The anti-Leishmania effect of imatinib was confirmed by MTS and direct microscopy. Further study is recommended for evaluating possible therapeutic effects of imatinib on leishmaniasis in vivo.

Effect of CO2 Laser on the Prevention of White Spot Lesions During Fixed Orthodontic Treatment: A Randomized Clinical Trial.

OBJECTIVE: This study aimed to assess the effect of carbon dioxide (CO2) laser on prevention of white spot lesions (WSLs) associated with fixed orthodontic treatment. METHODS: In this parallel controlled trial, 554 maxillary anterior teeth in 95 patients with age range of 12-30 years were included. The samples were randomly divided in two groups: 1) CO2 laser (n=278) and 2) control (n=276) groups. Following bracket attachment, the teeth in the laser group were exposed to CO2 laser (0.4 mw, 10.6 µm, 5 Hz) for 20 s, and the control group received placebo light. Incidence, severity, and extent of the lesions were assessed in four surface regions (gingival, incisal, mesial, and distal) at baseline and 6 months post-irradiation. The inter-group comparison was performed by the Mann-Whitney U test and McNemar analysis. RESULTS: A significant difference regarding WSLs incidence in all teeth was observed between the two study groups (p<0.001). The two study groups illustrated a significant difference in lesion extent and incidence in incisal, mesial, and distal regions (p<0.05). The WSLs were significantly different in terms of severity in the incisal and mesial sites (p<0.05). CONCLUSION: The CO2 laser irradiation seemed to effectively prevent incidence of WSLs. In addition, its effectiveness varied depending on the surface region.

A Novel Strategy for Enhance Potentiation of Meglumine antimoniate against Leishmania major In Vitro.

BACKGROUND: We aimed to design a different method of drug delivery for increased transfer of the choice drug (meglumine antimoniate) within the host cells. Therefore, listeriolysin O (LLO), a bacterial product which is a member of pore-forming peptides was used as an enhancer factor with meglumine antimoniate in order to facilitate the transition of the drug across macrophage membrane. METHODS: LLO was produced in Isfahan University of Medical Sciences in 2016, by expressing the hlyA gene in Escherichia coli and purified using affinity chromatography. Cytotoxicity of the purified protein was investigated in an in vitro model of macrophage Leishmania infection. RESULTS: LLO was cytotoxic against murine macrophage cells (J774-A1) and amastigote forms of L. major (MRHO/IR/75/ER). It was less toxic to macrophages (CC50=2.56 µg ml-1 ±0.09) than to the parasites (IC50=1.72 µg ml-1 ±0.07). Moreover, noncytotoxic concentration of LLO (0.006 ug ml-1) potentiated the cytotoxicity induced by low dose concentration of meglumine antimoniate. Very little dose of meglumine antimoniate was needed when combined with the LLO (IC50=12.63 µg ml-1 ±0.13) in comparison with the cytotoxicity induced when the drug is used alone (IC50=46.17 µg ml-1 ±0.28). CONCLUSION: The combination of pore-forming proteins with anti-leishmanial agents could increase the advantage of anti-leishmanial drugs. Since lower concentrations of anti-leishmanial drugs can reduce undesirable side effects of chemotherapy trials carried out in animal models and then in humans with this system.

The Rate of Demineralization in the Teeth Prepared by Bur and Er:YAG Laser.

Introduction: The present in vitro study evaluated the recurrence rate of caries following cavity preparations with bur (conventional technique) and irradiation by Erbium:Yttrium- Aluminum-Garnet (Er:YAG) laser through micro hardness test. Methods: A total of 72 human extracted molars were randomly divided into 3 groups and class 5 cavities were prepared on them with 3 different methods: G1) conventional bur, G2) Er:YAG laser irradiation alone and G3) laser irradiation + laser treatment. The specimens were immersed in the artificial caries solution with pH of 2.0 and 5.0 (12 days) and then immersed in re-mineralizing solution with pH of 7.0 (25 days). The specimens were longitudinally sectioned and their Vickers micro hardness was determined. Data were statistically analyzed by means of three-way analysis of variance (ANOVA) and Tukey multiple comparisons tests. Results: The micro hardness of the samples was affected by substrate type (enamel and dentin) and low values were achieved in dentin (P<0.001). Moreover, no significant difference was observed between preparation methods by bar and laser irradiation alone (P ≤0.499). Although laser irradiation + laser treatment decreased micro hardness of enamel compared to other methods. In dentin samples, different methods of preparation showed no significant effect on micro hardness (P ≤0.874). Conclusion: Due to the similar values of micro hardness following G1 and G2, it seems that Er:YAG laser alone is as much effective as the conventional bur to prevent recurrence caries. However, because of the high prices of laser instruments, bur preparations can be done commonly.

SEROPREVALENCE OF TOXOPLASMA GONDII INFECTION AMONG PATIENTS ADMITTED TO AL-ZAHRA HOSPITAL, ISFAHAN, IRAN.

BACKGROUND: Toxoplasma gondii (T. gondii) infection is one of the most common parasitic infections among humans and other warm-blooded animals worldwide. The aim of this study was to evaluate toxoplasmosis status in patients admitted to Al-Zahra hospital, Isfahan, Iran. METHODS: This cross-sectional study was conducted from October 2012 to January 2015. During this period, 716 patients referred to AI-Zahra hospital in Isfahan city, Iran, were studied to investigate the IgG and IgM antibodies against T. gondii using ELISA kit. The data were analysed by Chi-square and Fisher's exact tests. In addition, the relation of data with age and sex were also examined. RESULTS: Among 716 patients, 21 patients (2.9%) had positive IgM and 288 patients (40.2%) had positive IgG titer against T. gondii. Data analysis by Chi-square and Fisher's exact tests revealed that there was no significant relationship between IgG titer and age (p > 0.05). Additionally, there was no relationship between IgM titer and age (p > 0.05). The data showed that there was no relationship between IgG and IgM antibody titer and sex (p > 0.05). CONCLUSION: The prevalence of toxoplasmosis in Isfahan inhabitants seems fairly high but it can be concluded that the rate of seropositive patient is moderate comparing to other regions of country. Accordingly, the authors propose that all sensitive patients have to be tested for T. gondii antibody in order to prevent the consequences of disease.

Shear bond strength of the repair composite resin to zirconia ceramic by different surface treatment.

INTRODUCTION: The purpose of this study is the evaluation of the amount of surface roughness (Ra) of Zirconia Ceramic following different surface treatments as well as the assessment of its shear bond strength to composite resin. METHODS: 40 sintered zirconia ceramic block samples were randomly divided in 4 groups of 10 and underwent the following surface treatments: a) Control group without treatment b) Air abrasion with Al2O3 particles (50um) c) Er:YAG laser with 2W power for 10s d) Nd:YAG laser with 1.5W power for 2min Then the mean surface roughness (Ra) was evaluated by profilometer. In the next step, Alloy primer was used on a section of 9mm(2) on the samples following the manufacturer's instructions. After that Clearfil AP-X composite resin in cylinder shape with an internal diameter and height of 3mm were cured on the sections mentioned. At the end, all samples were tested to assess the shear bond strength by the Universal Testing Machine at a speed of 0.5mm/min until fracture occurred. The mean shear bond strengths were calculated and statistically analyzed by One Way ANOVA. RESULTS: ANOVA analysis showed that roughness (Ra) was significantly different between the groups (P≤0.05). Ra was higher in the Nd:YAG group compared to the other groups (P≤0.05). The lower Ra was related to the control group. Air abrasion group showed highest amounts of shear bond strength and Nd:YAG laser group demonstrated lower amounts of shear bond strength (P≤0.05). CONCLUSION: Various surface treatments are differently effective on bond strength. Air abrasion is the most effective method to condition zirconia ceramic surfaces.