Impedance between the electrode inserted in a root canal of a human tooth and the outer electrode placed on the oral mucosa serves as a measure of the root canal length, a vital parameter necessary for efficient endodontic procedure in dentistry. For better understanding of current conduction through the tooth, the impedance has been measured on extracted teeth (in vitro) and further used to develop corresponding electrical lumped element models. For modeling the metal/solution interface and complex structure of the tooth, Fricke's constant phase elements are employed. More detailed insight into current conduction is given by numerical simulation. Numerical simulation demonstrates the influence on the impedance of several important parameters, such as dentin conductance, canal preparation, and solution conductance.

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OBJECTIVE.  The study investigated the influence of exposure to anti-asthmatic medications and of various factors on the caries prevalence in children in Slovenia. METHODS.  The study population consisted of children aged 2 to 17 years (n = 220) under treatment for asthma, who had used anti-asthmatic medications for at least 1 year; 220 controls were matched for age. Caries status was determined by the number of decayed, missing, and filled surfaces through clinical examination by two calibrated dentists using the International Caries Detection and Assessment System-II scoring criteria. Questionnaires completed by parents and data from the patients' medical records provided information on various confounding factors. RESULTS.  Asthmatic children had significantly higher (P ≤ 0.01) prevalence of caries on primary and permanent teeth in all age groups, and the proportion of caries-free children was significantly smaller (P ≤ 0.05). In multivariate regression analysis, asthma diagnosis, child's age, daily use of inhaled glucocorticoids, length and frequency of medicine application, spacer use, mouth rinsing with water after medicine application, parents' education, frequent food and drink consumption, and frequency of toothbrushing were associated with caries experience of asthmatic children. CONCLUSION.  Children with asthma who had used anti-asthmatic medications had higher caries experience in primary and permanent teeth.

BackgroundMolar-root incisor malformation (MRIM) is a novel dental phenotype likely related to a patient’s past medical history. This case aimed to confirm MRIM by histological and scanning electron microscopy (SEM) examination for the first time in a patient diagnosed with autoimmune lymphoproliferative syndrome (ALPS) and to propose a possible link between ALPS and MRIM that could be attributable to abnormally proliferated bone marrow.Case presentationA 12.5-year-old boy with an extensive medical history, including diagnosis of ALPS, was examined clinically and radiologically to elucidate the reason for pain primarily originating from the area of the lower left permanent first molar tooth (PFM; tooth 36). Dental examination and radiographic survey revealed abnormal pulp cavity morphology of all four PFMs, and these were extracted, resolving the dental pain in the patient. The extracted PFMs were subjected to light microscopy, SEM evaluation and mineral density and elemental composition analyses. Histology of two PFMs revealed the presence of dentin-, bone- and cartilage-like tissues with abundant blood vessels occupying the majority of the pulp chamber. The root canals were obliterated with mineralized structures resembling pulp stones. Two different, highly mineralized abnormal tissues filling the majority of the pulp chamber revealed by SEM and confirming the diagnosis of MRIM displayed a mineral density and elemental composition similar to those of enamel and dentin, respectively.ConclusionsIt appears likely that in addition to the complex medical history during early childhood in the present case, extensive lymphoid infiltrates that are possible in ALPS patients can be regarded as a cofactor in the development of MRIM by exerting considerable pressure on the developing tooth bud and providing cells capable of differentiating into diverse cell types.

The CS demonstrated greater accuracy in detecting proximal lesions than ICDAS-II and BW, although without significantly higher specificity.

Exposure to widespread lipophilic and bioaccumulative polychlorinated biphenyls (PCBs) induces diverse biochemical and toxicological responses in various organs, including the bone. The aim of this study was to evaluate the changes in growth rate, geometry, serum, and bone biochemical parameters and biomechanics of juvenile rat femur induced by lactational exposure to nonplanar PCB-155 and planar PCB-169 individually and in combination. Fifteen lactating Wistar rats were divided into four groups (PCB-169, PCB-155, PCB-155+169, and control), and PCBs were administered intraperitoneally at different time points after delivery. Femurs from 22-day-old offspring were analyzed by microCT, three-point bending test and inductively coupled plasma-mass spectrometry (ICP-MS) to obtain data on bone geometry, biomechanics and mineral composition. The serum levels of calcium, phosphate and alkaline phosphatase were also determined. Lactational exposure to planar PCB-169 resulted in shorter and thinner femurs, reduced endosteal and periosteal perimeters, smaller total cross-sectional and medullary areas, and lowered serum bone marker levels and calcium levels in the bone, while femur mechanical properties were not significantly altered. The changes observed in the combination exposure (PCB-155+169) group were similar to those observed in the PCB-169 group but were less pronounced. In summary, our results demonstrate that alterations in lactationally exposed offspring were primarily induced by planar PCB-169. The milder outcome in the combined group suggested that the PCB-169-mediated toxic effects on the bone might be reduced by a nonplanar PCB-155 congener. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1135-1146, 2017.

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