Registration and Measurement of Right and Left Mediotrusion by using the Method of Electronic Axiography

PURPOSE. The aim of this study was to register and measure lower jaw movements and to analyse the measured length of maximal right and left mediotrusion movement in asymptomatic and symptomatic subjects. MATERIALS AND METHODS. A symptomatic group consisted of 51 subjects with temporomandibular disorders. A control group consisted of 43 subjects without signs and symptoms of temporomandibular joint disorders. In the symptomatic group of subjects signs and symptoms of temporomandibular disorders were crepitation, bruxism, sensitivity, pain in the temporomandibular joint and muscles, as well as pain and sensitivity in the region surround and anterior to the ear, together with difficulties while opening the mouth. Each subject was registered by the GAMMA CADIAX system for registration of positions and movement of the lower jaw, which consist of a convetional SAM axiograph, electronic device for drawing of curves with a computer. RESULTS. No significant differences were found between the groups of subject for the measured variables. CONCLUSION. The results of the length of the mandibular and condyle movements are important, alhough unreliable indicators of temporomandibular join function. Description analysis of a graphic recording of mandibular and TMJ movement remains a precise evaluation method for determination of TMJ dysfunction

Control and Correction of Occlusal Relations of Complete Dentures

Control and correction of occlusal relations are a constituent part of clinical and laboratory procedures of complete denture fabrication. Denture materials and fabrication procedures cannot ensure dimensionally correct complete dentures, and therefore it is necessary to check the occlusion. A remount procedure is carried out in order to establish correct occlusal contacts of denture teeth by mounting the finished dentures back on the articulator. There are several reasons for remounting: changed volume of the acrylic resin during polymerisation, dimensional changes in the early days of wearing due to water absorption in the acrylic base and placement of denture bases to the denture foundation area. Remounting starts with fabrication of transfer casts, determination and transfer of interarch relations to the articulator. When the dynamic concept of occlusion is chosen, priority is given to incisor or canine teeth guided occlusion. Remounting should be a constituent part of complete denture fabrication. Supported by Ministry of Science and Technology. Republic of Croatia, Project No. 065010

Control and Correction of Occlusal Relations of Complete Dentures

Control and correction of occlusal relations are a constituent part of clinical and laboratory procedures of complete denture fabrication. Denture materials and fabrication procedures cannot ensure dimensionally correct complete dentures, and therefore it is necessary to check the occlusion. A remount procedure is carried out in order to establish correct occlusal contacts of denture teeth by mounting the finished dentures back on the articulator. There are several reasons for remounting: changed volume of the acrylic resin during polymerisation, dimensional changes in the early days of wearing due to water absorption in the acrylic base and placement of denture bases to the denture foundation area. Remounting starts with fabrication of transfer casts, determination and transfer of interarch relations to the articulator. When the dynamic concept of occlusion is chosen, priority is given to incisor or canine teeth guided occlusion. Remounting should be a constituent part of complete denture fabrication. Supported by Ministry of Science and Technology. Republic of Croatia, Project No. 065010

Exploring NMR ensembles of calcium binding proteins: Perspectives to design inhibitors of protein-protein interactions

<p>Abstract</p> <p>Background</p> <p>Disrupting protein-protein interactions by small organic molecules is nowadays a promising strategy employed to block protein targets involved in different pathologies. However, structural changes occurring at the binding interfaces make difficult drug discovery processes using structure-based drug design/virtual screening approaches. Here we focused on two homologous calcium binding proteins, calmodulin and human centrin 2, involved in different cellular functions via protein-protein interactions, and known to undergo important conformational changes upon ligand binding.</p> <p>Results</p> <p>In order to find suitable protein conformations of calmodulin and centrin for further structure-based drug design/virtual screening, we performed <it>in silico </it>structural/energetic analysis and molecular docking of terphenyl (a mimicking alpha-helical molecule known to inhibit protein-protein interactions of calmodulin) into X-ray and NMR ensembles of calmodulin and centrin. We employed several scoring methods in order to find the best protein conformations. Our results show that docking on NMR structures of calmodulin and centrin can be very helpful to take into account conformational changes occurring at protein-protein interfaces.</p> <p>Conclusions</p> <p>NMR structures of protein-protein complexes nowadays available could efficiently be exploited for further structure-based drug design/virtual screening processes employed to design small molecule inhibitors of protein-protein interactions.</p

Influence of Occlusal Interference on the Prevalence of Temporomandibular Disorders

The significance of occlusal interference in the etiology of temporomandibular disorders has been questioned in numerous recent articles. The aim of this study was to determine the prevalence of the clinical signs and symptoms of temporomandibular disorders in a young male nonpatient population and to investigate a possible association between the signs and symptoms of temporomandibular disorders and occlusal interference. A questionnaire including data from history and clinical functional examination was used in the study. All subjects (a total of 230) were male (army recruits), of 19 to 28 years of age (mean 21.3). Temporomandibular joint clicking was reported in 91 subjects, temporomandibular joint pain on palpation and functional loading in 78 subjects, masticatory muscle pain on palpation and functional loading in 58 subjects, tension type headache in 30 subjects, and mandibular deviation on opening and closing movements greater than 2 mm in 43 subjects. The prevalence of occlusal interference in percentage in 230 young adults, 65% had no occlusal interference during examination of the functional state of occlusion, while 14%subjects had centric slide between centric relation and maximum intercuspation, 5% subjects had working side interference and 16% subjects had non-working side interference during lateral and protrusive mandibular movements. Clinical signs and symptoms were correlated with occlusal interference, although their correlation cannot be considered unique or dominant in definition of a temporomandibular disorder population

The location of the axon initial segment affects the bandwidth of spike initiation dynamics

The dynamics and the sharp onset of action potential (AP) generation have recently been the subject of intense experimental and theoretical investigations. According to the resistive coupling theory, an electrotonic interplay between the site of AP initiation in the axon and the somato-dendritic load determines the AP waveform. This phenomenon not only alters the shape of AP recorded at the soma, but also determines the dynamics of excitability across a variety of time scales. Supporting this statement, here we generalize a previous numerical study and extend it to the quantification of the input-output gain of the neuronal dynamical response. We consider three classes of multicompartmental mathematical models, ranging from ball-and-stick simplified descriptions of neuronal excitability to 3D-reconstructed biophysical models of excitatory neurons of rodent and human cortical tissue. For each model, we demonstrate that increasing the distance between the axonal site of AP initiation and the soma markedly increases the bandwidth of neuronal response properties. We finally consider the Liquid State Machine paradigm, exploring the impact of altering the site of AP initiation at the level of a neuronal population, and demonstrate that an optimal distance exists to boost the computational performance of the network in a simple classification task. Copyright

Representation of Dynamical Stimuli in Populations of Threshold Neurons

Many sensory or cognitive events are associated with dynamic current modulations in cortical neurons. This raises an urgent demand for tractable model approaches addressing the merits and limits of potential encoding strategies. Yet, current theoretical approaches addressing the response to mean- and variance-encoded stimuli rarely provide complete response functions for both modes of encoding in the presence of correlated noise. Here, we investigate the neuronal population response to dynamical modifications of the mean or variance of the synaptic bombardment using an alternative threshold model framework. In the variance and mean channel, we provide explicit expressions for the linear and non-linear frequency response functions in the presence of correlated noise and use them to derive population rate response to step-like stimuli. For mean-encoded signals, we find that the complete response function depends only on the temporal width of the input correlation function, but not on other functional specifics. Furthermore, we show that both mean- and variance-encoded signals can relay high-frequency inputs, and in both schemes step-like changes can be detected instantaneously. Finally, we obtain the pairwise spike correlation function and the spike triggered average from the linear mean-evoked response function. These results provide a maximally tractable limiting case that complements and extends previous results obtained in the integrate and fire framework

Effective Stimuli for Constructing Reliable Neuron Models

The rich dynamical nature of neurons poses major conceptual and technical challenges for unraveling their nonlinear membrane properties. Traditionally, various current waveforms have been injected at the soma to probe neuron dynamics, but the rationale for selecting specific stimuli has never been rigorously justified. The present experimental and theoretical study proposes a novel framework, inspired by learning theory, for objectively selecting the stimuli that best unravel the neuron's dynamics. The efficacy of stimuli is assessed in terms of their ability to constrain the parameter space of biophysically detailed conductance-based models that faithfully replicate the neuron's dynamics as attested by their ability to generalize well to the neuron's response to novel experimental stimuli. We used this framework to evaluate a variety of stimuli in different types of cortical neurons, ages and animals. Despite their simplicity, a set of stimuli consisting of step and ramp current pulses outperforms synaptic-like noisy stimuli in revealing the dynamics of these neurons. The general framework that we propose paves a new way for defining, evaluating and standardizing effective electrical probing of neurons and will thus lay the foundation for a much deeper understanding of the electrical nature of these highly sophisticated and non-linear devices and of the neuronal networks that they compose