Background. In this study antimicrobial effect of ethanolic and aqueous extracts of Juglans regia bark in Iran was evaluated on four different oral bacteria, Streptococcus mutans, Streptococcus salivarius, Streptococcus sanguis, and Staphylococcus aureus. Methods. Aqueous and ethanol extracts of Juglans regia bark were prepared by using disk diffusion technique and Minimal Inhibitory Concentration (MIC) methods. Tetracycline 30 μg and Erythromycin 15 μg were used as positive control and water as negative control in disk diffusion and MIC methods. Data were analyzed by ANOVA test. Results. The results showed that S. sanguis and S. mutans were the most sensitive and the most resistant bacteria against ethanolic and aqueous extracts, respectively. Ethanolic extract had significant antibacterial effect against all tested bacteria. Aqueous extract did not show antibacterial effect on S. mutans, in contrast to ethanolic extract. Aqueous extract had significantly antibacterial effect against Staphylococcus aureus, S. salivarius, and S. sanguis compared to control (P < 0.0001), but it did not show effect on S. mutans when compared with Erythromycin. According to the obtained MIC values, ethanol extract of Juglans regia bark had the lowest rate. Conclusion. The results may provide the basis for using natural antimicrobial substance for oral hygiene prophylaxis purposes.

Background. There is no doubt that the success of the dental implants depends on the stability. The aim of this work was to measure the stability of dental implants prior to loading the implants, using a resonance frequency analysis (RFA) by Osstell mentor device. Methods. Ten healthy and nonsmoker patients over 40 years of age with at least six months of complete or partial edentulous mouth received screw-type dental implants by a 1-stage procedure. RFA measurements were obtained at surgery and 1, 2, 3, 4, 5, 7, and 11 weeks after the implant surgery. Results. Among fifteen implants, the lowest mean stability measurement was for the 4th week after surgery in all bone types. At placement, the mean ISQ obtained with the magnetic device was 77.2 with 95% confidence interval (CI) = 2.49, and then it decreased until the 4th week to 72.13 (95% CI = 2.88), and at the last measurement, the mean implant stability significantly (P value <0.05) increased and recorded higher values to 75.6 (95% CI = 1.88), at the 11th week. Conclusions. The results may be indicative of a period of time when loading might be disadvantageous prior to the 4th week following implant placement. These suggestions need to be further assessed through future studies.

BackgroundThe aim of this study is to compare the microleakage of Class II dental composite resin restorations which have been cured by three different LED (light emitting diode) light curing modes compared to control samples cured by QTH (quartz tungsten halogen) light curing units (LCUs), to determine the most effective light curing unit and mode of curing.ResultsIn this experimental study, class II cavities were prepared on 100 sound human premolars which have been extracted for orthodontic treatment. The teeth were randomly divided into four groups; three experimental and one control group of 25 teeth each. Experimental groups were cured by either conventional, pulse-delay, or ramped curing modes of LED. The control group was cured for 20 seconds by QTH. The restorations were thermocycled (1000 times, between 5 and 55°C, for 5 seconds dwell time), dyed, sectioned mesio-distally and viewed under stereo-microscope (40×) magnification. Teeth were then scored on a 0 to 4 scale based on the amount of microleakage. The data were analyzed by Chi-square test.No significant difference was demonstrated between the different LCUs (light curing units), or modes of curing, at the enamel side (p > 0.05). At the dentin side, all modes of LED curing could significantly reduce microleakage (p < 0.05). The results suggest that slow start curing improves marginal integrity and seal. High intense curing endangers those aims.ConclusionsComparison between the three LED mode cured composite resin restorations and QTH curing showed LED curing in all modes is more effective than QTH for reducing microleakage. Both LED and QTH almost completely eliminate the microleakage on the enamel side, however none of them absolutely eliminated microleakage on the dentin side.

Background. Melatonin (MT: N-acetyl-5-methoxytryptamine) is a neuroendocrine hormone secreted mainly by the pineal gland in the brain. MT is produced with a circadian rhythm characterized by elevated blood levels during the night. In healthy individuals, maximal secretion of MT occurs between midnight and 2:00 am, whereas the minimal production occurs during the day. MT can be determined by repeated measurement of plasma or salivary MT or urine sulfatoxy-melatonin. Melatonin has powerful antioxidant effects, has an immunomodulatory role, stimulates the synthesis of type I collagen fibers, and promotes bone formation. Melatonin is also secreted in the saliva, although its role in the mouth is not known well. The purpose of this study was to examine the correlation between salivary melatonin level and periodontal diseases.Methods. Fifty subjects by mean age of40.44±6.38years were equally divided into 5 groups: 10 healthy subjects, 10 subjects with gingivitis, 10 subjects with localized moderate chronic periodontitis, 10 subjects with generalized moderate chronic periodontitis, and 10 subjects with generalized severe chronic periodontitis. Saliva samples were collected from all the subjects and melatonin levels were determined using an enzyme-linked immunosorbent assay. Two-way and one-way ANOVA and Tukey test were used to analyze relationships among variables.Results. Healthy subjects had significantly higher salivary melatonin level (5.29±0.50 pg/mL) compared to patients with gingivitis (4.35±0.30 pg/mL) (P<0.001). The difference between salivary melatonin level in patients with gingivitis and periodontitis was significant (P<0.001). Level of melatonin in patients with generalized severe chronic periodontitis (3.39±0.10 pg/mL) was significantly lower than that in other groups (P<0.01).Conclusions. This study determined that salivary melatonin level in patients with periodontal diseases is lower than that in healthy subjects. Consequently we conclude that there is a negative correlation between melatonin level and the severity of disease, suggesting that melatonin might have a protective role against periodontal diseases, although further research is required to validate this hypothesis.