Traumatic Neuroma Following Sagittal Split Osteotomy of the Mandible

A 16-year-old male underwent bilateral sagittal split osteotomy of the mandible to correct a mandibular deficiency. Twenty-one years later, a routine panoramic radiograph revealed a radiolucent lesion on the left side of the mandible. The lesion was biopsied. As the patient did not have symptoms and the lesion was connected to the inferior alveolar nerve, the lesion was not totally excised in order to preserve nerve function. The histological features were consistent with traumatic neuroma, and no further surgical procedure was planned

Accuracy of maxillary positioning after standard and inverted orthognathic sequencing

This study aimed to compare the accuracy of maxillary positioning after bimaxillary orthognathic surgery, using 2 sequences. A total of 80 cephalograms (40 preoperative and 40 postoperative) from 40 patients were analyzed. Group 1 included radiographs of patients submitted to conventional sequence, whereas group 2 patients were submitted to inverted sequence. The final position of the maxillary central incisor was obtained after vertical and horizontal measurements of the tracings, and it was compared with what had been planned. The null hypothesis, which stated that there would be no difference between the groups, was tested. After applying the Welch t test for comparison of mean differences between maxillary desired and achieved position, considering a statistical significance of 5% and a 2-tailed test, the null hypothesis was not rejected (P>.05). Thus, there was no difference in the accuracy of maxillary positioning between groups. Conventional and inverted sequencing proved to be reliable in positioning the maxilla after LeFort I osteotomy in bimaxillary orthognathic surgeries1175567574FUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPER

Stability and response analysis of a pipe with internal flow analyzed with an uncertain computational model

International audienceThis paper treats the problem of pipes conveying fluid, which has several engineering applications, such as micro-systems and drill-string dynamics. The aim of this work is twofold: (1) propose a stochastic model for the fluid-structure interaction considering modeling errors and (2) analyze the stability of the stochastic system. The Euler-Bernoulli model is used to model the pipe and the plug flow model is used to take into account the presence of the internal flow. The resulting differential equation is discretized by means of the finite element method and a reduced-order model is constructed with the normal modes of the beam model. A variation of the nonparametric probabilistic approach is used to model uncertainties in the fluid-structure interaction, since this approach is able to take into account modeling errors. The numerical results show how the random response of the system changes for different levels of uncertainties. The probability of instability is also computed for different levels of uncertainties

Dynamic stability of a pipe conveying fluid with an uncertain computational model

International audienceThe deterministic stability analysis developed by Paidoussis and Issid (1974) is extended to the case for which there are model uncertainties induced by modeling errors in the computational model. The aim of this work is twofold: (1) to propose a probabilistic model for the fluid-structure interaction considering modeling errors and (2) to analyze the stability and reliability of the stochastic system. The Euler-Bernoulli beam model is used to model the pipe and the plug flow model is used to take into account the internal flow in the pipe. The resulting differential equation is discretized by means ofvthe finite element method and a reduced-order model is constructed from some eigenmodes of thevbeam. A probabilistic approach is used to model uncertainties. The proposed strategy takes into account global uncertainties related to the noninertial coupled fluid forces (related to damping and stiffness). The resulting random eigenvalue problem is used to analyze flutter and divergence unstable modes of the system for different values of the dimensionless flow speed