Pre-surgical treatment planning of maxillary canine impactions using panoramic vs cone beam CT imaging

Objectives: The aim of this prospective study was to compare the impact of using two-dimensional (2D) panoramic radiographs and three-dimensional (3D) cone beam CT for the surgical treatment planning of impacted maxillary canines. Methods: This study consisted of 32 subjects (19 females, 13 males) with a mean age of 25 years, referred for surgical intervention of 39 maxillary impacted canines. Initial 2D panoramic radiography was available, and 3D cone beam CT imaging was obtained upon clinical indication. Both 2D and 3D pre-operative radiographic diagnostic sets were subsequently analysed by six observers. Perioperative evaluations were conducted by the treating surgeon. McNemar tests, hierarchical logistic regression and linear mixed models were used to explore the differences in evaluations between imaging modalities. Results: Significantly higher confidence levels were observed for 3D image-based treatment plans than for 2D image-based plans (p < 0.001). The evaluations of canine crown position, contact relationship and lateral incisor root resorption were significantly different between the 2D and 3D images. By contrast, pre- and perioperative evaluations were not significantly different between the two image modalities. Conclusions: Surgical treatment planning of impacted maxillary canines was not significantly different between panoramic and cone beam CT images.status: publishe

Variation in costs of cone beam CT examinations among healthcare systems

Objectives: To analyse the costs of cone beam CT (CBCT) in different healthcare systems for patients with different clinical conditions. Methods: Costs were calculated for CBCT performed in Cluj (Romania), Leuven (Belgium), Malmö (Sweden) and Vilnius (Lithuania) on patients with (i) a maxillary canine with eruption disturbance, (ii) an area with tooth loss prior to implant treatment or (iii) a lower wisdom tooth planned for removal. The costs were calculated using an approach based on the identification, measurement and valuation of all resources used in the delivery of the service that combined direct costs (capital equipment, accommodation, labour) with indirect costs (patients' and accompanying persons' time, "out of pocket" costs for examination fee and visits). Results: The estimates for direct and indirect costs varied among the healthcare systems, being highest in Malmö and lowest in Leuven. Variation in direct costs was mainly owing to different capital costs for the CBCT equipment arising from differences in purchase prices (range J148 000-227 000). Variation in indirect costs were mainly owing to examination fees (range J0-102.02). Conclusions: Cost analysis provides an important input for economic evaluations of diagnostic methods in different healthcare systems and for planning of service delivery. Additionally, it enables decision-makers to separate variations in costs between systems into those due to external influences and those due to policy decisions. A cost evaluation of a dental radiographic method cannot be generalized from one healthcare system to another, but must take into account these specific circumstances

Система поддержки принятия решений при проектировании автоматической противопожарной защиты вентилируемых помещений

В статье приведено исследование современного состояния проблемы моделирования опасных факторов пожара в помещении. Представлены результаты разработки системы поддержки принятия решений для моделирования динамики опасных факторов пожара в вентилируемых помещениях на начальной стадии пожара с последующим выводом управляющего решения по оптимальным для применения в этих помещениях типам автоматических установок пожаротушения и пожарной сигнализации, а также координатам размещения их элементов.The article presents the study of contemporary problems of modeling of fire hazards in the premises. The results of development of the system of decision support for modelling the dynamics of fire hazards in the premises at the initial stage of the fire and then outputting a control solution that is optimal for use in these areas types of automatic fire extinguishing and fire alarm systems, and coordinates the placement of their elements

A Method for Designing FIR Filters with Arbitrary Magnitude Characteristic Used for Modeling Human Audiogram

This paper presents an iterative method for designing FIR filters that implement arbitrary magnitude characteristics, defined by the user through a set of frequency-magnitude points (frequency samples). The proposed method is based on the non-uniform frequency sampling algorithm. For each iteration a new set of frequency samples is generated, by processing the set used in the previous run; this implies changing the samples location around the previous frequency values and adjusting their magnitude through interpolation. If necessary, additional samples can be introduced, as well. After each iteration the magnitude characteristic of the resulting filter is determined by using the non-uniform DFT and compared with the required one; if the errors are larger than the acceptable levels (set by the user) a new iteration is run; the length of the resulting filter and the values of its coefficients are also taken into consideration when deciding a re-run. To demonstrate the efficiency of the proposed method a tool for designing FIR filters that match human audiograms was implemented in LabVIEW. It was shown that the resulting filters have smaller coefficients than the standard one, and can also have lower order, while the errors remain relatively small