Comparison of antibacterial effects of orthodontic composites containing different nanoparticles on Streptococcus mutans at different times

ABSTRACT Introduction: Plaque accumulation can cause white spot lesions. Adding nanoparticles to composites can be effective in reducing the number and function of microorganisms. Objective: The aim of this study was to evaluate the antibacterial effects of orthodontic composites containing different nanoparticles on Streptococcus mutans at different times. Methods: Hydroxyapatite, titanium oxides, zinc oxide, copper oxide and silver oxide nanoparticles were prepared at 0.5% and 1% weight concentrations. Accordingly, ten study groups and one control group were obtained. Then, 26 composite discs were prepared from each group. Strain of Streptococcus mutans was cultured, and colonies of Streptococcus mutans were counted. Further bacterial culture was swapped onto enriched Mueller-Hinton agar. The composites were placed on the culture medium, and after incubation the diameter of growth inhibition was measured. To investigate the long-term effect of nanoparticles, the colonies were counted at days 3, 15 and 30. Results: The results showed that 1% copper oxide and 1% silver oxide significantly reduced the number of bacteria (p< 0.05), but there was no significant difference between the other groups and control group (p> 0.05). At day three, there was a significant difference between control group and 0.5% silver oxide, 1% silver oxide and 1% copper oxide groups (p< 0.05). However, colonies had grown in all groups at day 30 but showed no significant difference with control group (p> 0.05). Conclusion: Addition of 1% copper oxide and 1% silver oxide has short-term antibacterial effects, so the clinical use of these nanoparticles cannot be justified.

RESUMO Introdução: O acúmulo de placa bacteriana pode causar lesões de mancha branca. A adição de nanopartículas nas resinas ortodônticas pode ser eficaz para reduzir o número e a função dos microrganismos. Objetivo: O objetivo do presente estudo foi avaliar os efeitos antibacterianos contra o Streptococcus mutans, em diferentes intervalos de tempo, de resinas ortodônticas contendo diferentes tipos de nanopartículas. Métodos: Foram criados dez grupos experimentais e um grupo controle contendo nanopartículas de hidroxiapatita, óxido de titânio, óxido de zinco, óxido de cobre e óxido de prata em concentrações de 0,5% e 1%. Em seguida, foram preparados 26 discos de resina para cada grupo. Colônias de Streptococcus mutans foram cultivadas e contadas. Posteriormente, as culturas bacterianas foram colocadas em solução de ágar Mueller-Hinton. Os discos de resina foram colocados no meio de cultura e, depois da incubação, mediu-se o diâmetro de inibição do crescimento. Para avaliar os efeitos em longo prazo das nanopartículas, as colônias foram analisadas após 3, 15 e 30 dias. Resultados: Os resultados mostraram que o óxido de cobre a 1% e o óxido de prata a 1% reduziram significativamente o número de bactérias (p< 0,05), mas não houve diferença estatisticamente significativa entre os outros grupos e o grupo controle (p> 0,05). Após 3 dias, houve uma diferença significativa entre o grupo controle e os grupos óxido de prata a 0,5%, óxido de prata a 1% e óxido de cobre a 1% (p< 0,05). Porém, após 30 dias, as colônias haviam crescido em todos os grupos, sem diferença com o grupo controle (p> 0,05). Conclusão: A adição de óxido de cobre a 1% e óxido de prata a 1% apresenta efeitos antibacterianos apenas no curto prazo; portanto, o uso clínico dessas nanopartículas não se justifica.

Electrocardiographic and angiographic corelation of positive T-wave in V1 and coronary stenosis in patients with stable angina

During myocardial infarction ECG could determine the anatomic territory of necrotic myocardium. In stable angina the anatomic territory of ischemic myocardium is less correlated to ECG changes. In this study the correlation between positive T-Wave in lead V1 and the anatomic position of coronary arteries and the severity of stenotic lesion are investigated in patients with stable angina Method: this is a cross sectional analytical prospective study. The study was done in chamran hospital of Isfahan. Two hundred patients were involved in these study. 100 patients with negative T-wave in V1 as control group and hundred patients with positive T-wave in V1 as cases. All patient were angiographied. The cine films were interpreted by two cardiologists. Of patient who had positive T-wave in V1 84%, had a significant lesion on one or more of their coronary arteries. Patients with negative T-wave on V1 Only 54% had significant coronary lesion [P < 0.005]. Patients who had a positive T-Wave in V1 in 85% of cases, LAD, in 76.1% of cases, RCA and in 57.1% of cases the LCX had significant stenosis [P < 0.005]. Positive T wave on V1 predict more significant stenotic lesion of coronary arteries. But its correlation with anatomic location is more controversial

Asymptomatic shedding of genital herpes simplex virus [HSV-2] during pregnancy and neonatal outcome

The objectives of this study were detection of the asymptomatic shedding of genital herpes simplex virus type 2 [HSV-2] in the cervical secretion among the pregnant women late in pregnancy, through viral isolation by tissue culture [TC] and correlating it to the other methods of diagnosis or HSV-2, and also correlating it to the neonatal outcome. This study was conducted on 90 pregnant women, during the 3rd trimester who were coming for antenatal care, with no history, and no clinical findings of genital herpes. Asymptomatic HSV-2 shedding was determined by TC and polymerase chain reaction [PCR] of the cervical secretion, and the serologic status was determined by detecting HSV-2 IgM antibody. All of them were followed till delivery. An oropharyngeal swab of the neonates was taken for viral isolation by TC, and cord blood sample for HSV-IgM antibody. We found that: the percent of positivity of HSV-2 isolation by TC increased by increasing age, parity and number of previous abortions. [2] Asymptomatic shedding was detected by TC in 44/90 [48.9%] of the cervical swabs, HSV-2 DNA was detected in 43/44 [97.7%] of the +ve cervical swab, while serum HSV-2 IgM antibody was detected in 16/89 [18%] serum samples, and these represented 16/44 [36.4%] and 16/43 [37.2%] of the women with HSV-2 +ve TC and HSV-2 DNA detected by PCR respectively. [3] Only 3/90 [3.3%] oropharyngeal swabs showed HSV-2 +ve TC, their mothers were also HSV-2 +ve TC, while HSV-2 DNA, and HSV-2 IgM antibody could not be detected. [4] There was a significant correlation between HSV-2 isolation by TC and the perinatal outcome e.g. intrauterine fetal death [IUFD] still birth [SB], Apgar score, neonatal weight and number of neonates transferred to the neonatal intensive care unit [NICU], [5] There was a highly significant correlation between HSV-2 isolation by TC and HSV-2 DNA detection by PCR; while measurement of HSV-2 IgM antibody is of limited value in relation to both of them. HSV-2 isolation by TC is accurate, sensitive technique of low cost but of long turnaround time for diagnosis of asymptomatic shedding of HSV-2 during pregnancy. HSV-2 DNA detection by PCR can replace TC as it is more rapid but more expensive, and the cost benefit should be evaluated. So, TC is recommended to be used for screening HSV-2 infection, while PCR used for rapid diagnosis when subsequent intervention is essential e.g. antiviral treatment We could not conclusively relate these neonatal outcome to the asymptomatically shedded HSV-2