[Effect of low - level helium - neon laser irradiation on proliferation rate of cultured human fibroblasts in high glucose medium]

This study aimed to evaluate the effects of low level laser on human fibroblasts which were cultured in high glucose cultures. The human skin fibroblasts were maintained in Dulbecco's Modified Eagle's Medium [DMEM] in a humidified air-5% CO[2] atmosphere. The cells were cultured. Irradiation was carried out with Helium-Neon [He-Ne] laser unit with power output of 1.5 mW and the diameter of irradiating beam of 1.7 cm on the case groups. In the next step the cells were cultured in high glucose culture medium [15mM/L] for one week before laser irradiation. The irradiation was carried out with the same laser unit with power output of 1.5 mW and the diameter of irradiating beam of 1.7 cm on the case groups. Control cells did not receive laser. The cells were irradiated with three doses of 0.5, 1 and 2 J/cm[2] on three consecutive days. Cell proliferation was evaluated by dimethylthiazol-diphenyltetrazolium bromide [MTT] assay. Data were analyzed by student t test or Mann-Whitney-U test. Laser treatments of 0.5 [p-value=0.002] and 1 [p-value=0.046] had a stimulatory effect and three irradiations of 2 J/cm[2] had a negative effect [p-value=0.011] on proliferation rate of fibroblasts which were cultured in normal culture medium compared to non irradiated cells. All three doses of 0.5 [p-value=0.042], 1 [p-value=0.00] and 2 J/cm[2] [p-value=0.00] had a stimulatory effect on proliferation rate of fibroblasts which were cultured in culture medium with high glucose concentration [15mM/L] in comparison with hyper glycemic non irradiated cells. Low level laser irradiation with helium-neon unit on cultured human fibroblasts in normal and high glucose mediums increased their growth and proliferation

[ survey of the microleakage of mineral trioxide aggregate, root mineral trioxide aggregate and portland cement in repairing lateral perforations of the root canals]

Perforation is one of the most important problems which may occur during root canal therapy. To repair the perforation and to cut the relation of the root with the tissue of its peripheral environment, materials with adequate sealing ability and suitable price are needed. The aim of this study was to survey the microleakage of the three materials in the restoration of lateral perforations in the roots of the teeth. In this experimental study, 54 intact molar teeth were selected and assigned randomly to three groups. Canals were prepared with stepback technique and perforations were made at the apical third of the roots. The cavities were restored with MTA, Root MTA and Portland Cements type ?. The positive control group was subjected to perforation but no perforations were made in the negative control group. The teeth were covered with two layers of nail varnish restoring in 2% fushin solution for 24 hours after incubation. The teeth were sectioned and their leakage was measured by stereomicroscope. The records were analyzed by one- way ANOVA and LSD [Least Square Differences] test. In the positive group dye was completely entered in all perforation areas while no leakage was observed in the negative group. The statistical test showed no significant difference between MTA and Root MTA groups in terms of leakage [p>0.05]. But MTA and Root MTA had significant differences with Portland cement [p<0.0001]. Considering the results of this study, Root MTA may be considered as a substitute for Pro Root MTA in root canal treatment; however, using Portland type I cement needs more investigations

[ comparison on microleakage between a new experimental materials called cold ceramic and glass ionomer]

Aim and Background: the most important characteristic of a root end filling material is to provide an acceptable seal. Various materials have been already used as root end fillings in endonontic surgeries, none of them possess all desirable properties

Methods and Materials: in the present study, the sealing ability of a new experimental material known as cold ceramic was compared with glass ionomer. Cold ceramic contains calcium hydroxide as its chemical base, however, opposite Ca[OH],, it is capable of being set. Forty extracted human teeth were used in this experiment. The roots were cut at the cervical region from the crowns. After cleaning and shaping, 3mm at the apical region, of each tooth, was cut and a class I cavity of 2mm depth was prepared. The external surface, of each tooth, was covered by two layers of nailpolish. Then, the teeth were randomly divided into two groups; each was filled with one of the experimental materials, followed by embedding in normal saline solution for 10 days. The microleakage of all samples were then investigated electrochemically

Results: the results of this study showed statistically significant difference in the microleakage between two materials implying the minimum microleakage for the cold ceramic group

Conclusion: it can be concluded that the sealing ability of cold ceramic is more than glass ionomer