Effect of periodontal surgery on the salivary Herpes simplex virus-1 levels-a pilot study.

Background and aim: Herpes simplex viruses (HSV) are one of the most important groups of human pathogenic viruses. The prominent characteristic of this virus is latency and the ability to reactivate. One of the possible factors for reactivation of this virus is dental procedures. The aim of this study was to evaluate the salivary level of Herpes simplex viruses, before and after periodontal (crown lengthening) surgery and its relation with age and sex. Materials and methods: 30 HSV seropositive patients, who needed the crown lengthening surgery and accepted to cooperate in this research, were included as experimental group of this study. Unstimulated Saliva samples of the patients were collected in 1.5 ml micro-tubes, before and 24 h after the surgery, and were analyzed by Premix EX taq probe qpcr, using PCR real-time method. Results: No significant statistical differences were observed in the salivary level of HSV before and after crown lengthening procedure (p = 0.18). However, the level of HSV in saliva after surgery was significantly higher than its level before surgery in women as compared to men (p = 0.003). The differences in virus level did not have any significant relationship with patients' age (p = 0.9). Conclusion: It seems that periodontal (crown lengthening) surgery does not affect the level of HSV in saliva yet, but it could be one of the stimulators of increased HSV level after surgery in women as compared to men; but age does not play an important role in changes of level of virus before and after the surgery.

Phase transition in a network model of social balance with Glauber dynamics.

We study the evolution of a social network with friendly or enmity connections into a balanced state by introducing a dynamical model with an intrinsic randomness, similar to Glauber dynamics in statistical mechanics. We include the possibility of the tension promotion as well as the tension reduction in our model. Such a more realistic situation enables the system to escape from local minima in its energy landscape and thus to exit out of frozen imbalanced states, which are unwanted outcomes observed in previous models. On the other hand, in finite networks the dynamics takes the system into a balanced phase, if the randomness is lower than a critical value. For large networks, we also find a sharp phase transition at the initial positive link density of ρ_{0}^{*}=1/2, where the system transitions from a bipolar state into a paradise. This modifies the gradual phase transition at a nontrivial value of ρ_{0}^{*}≃0.65, observed in recent studies.