[Clinical accuracy of lpex apex locator for measurement of root canal length of primary molars]

Radiography is the most commonly used technique for root canal length determination; but its application in pedodontics is difficult due to problems namely the radiation hazards, superimposition of permanent teeth buds and uncooperative children. Electronic apex locator [EAL] is used for determination of root canal length. The aim of this study was to assess the accuracy of an Electronic Apex Locator [Ipex] in measuring the root canal length of primary teeth in-vivo. This clinical study was conducted on 50 root canals of primary teeth that had to be extracted. After local anesthesia induction and caries removal, access cavities were prepared and the length of root canals was measured using Ipex Electronic Apex Locator. After the extraction of teeth, the actual length of canals was measured using a #15 K file from a reference point. Data were analyzed using paired t-test and intra-class correlation coefficient. The accuracy of Ipex was 20% for accurate determination of actual root canal length, 66% for estimation within +/- 0.5mm of the apex and 80% for estimation within +/- 1mm of the apex. Paired t-test revealed a significant difference between the actual root canal length and the length displayed by Ipex [P<0.001]. A direct strong correlation existed between the length measured by Ipex and the actual root canal length [r=0.957] Ipex had a tendency to underestimate the actual root canal length. Since the working length is shorter than the actual root canal length, Ipex may be used for endodontic treatment of primary teeth

[Vitamin d alterations in food regimens and synaptic transmission in neuronal circuit]

In nervous system, through specific channels and some ionotropic receptors, calcium ion involves in synaptic transmission vitamin D takes an important role in cellular regulation as well. Calcium ion plays an important role in synaptic transmission through specific channels and some receptors such as NMDA receptors in the nervous system. In the present study we asked if alterations in vitamin D content of food regimens influence electrophysiological phenomena in hippocampal neuronal circuits. Adult rats under normal food regimen [CON], vitamin-D-free regimen [CON-D] or with a supplement of calcitriol [CON+D] were used in this study. Stimulating Schaffer colateral excitatory post synaptic field potentials [EPSP] were recorded in CA1 area of hippocampus. For inducing of long term potentiation [LTP] high frequency stimulation [HFS] was used as a tetanic stimulation. Changes in the amplitude of EPSPs were considered for comparison of the 3 tested groups. Our findings indicated that there was no difference between EPSP amplitude of the CON, CON+D and CON-D rats. On the other hand, LTP was induced only in the CON and CON+D animals. According to the findings, it seems that vitamin D deficiency considerably affect potentiation of the synaptic transmission. The probable mechanism can be vitamin D regulation of intracellular calcium concentration