Abstract. The study involved 300 elderly patients with chronic periapical periodontitis. The patients were randomly assigned into three groups. The treatment for group A used a Mtwo Ni-Ti rotary instrument combined with ultrasonic irrigation of a 2.5% NaOCl solution. The group B used the same instrument combined with ultrasonic irrigation of an active silver ion antibacterial solution. The group C used the same instrument combined with syringe irrigation of a 2.5% NaOCl solution. The root canal fillings were performed immediately after canal preparation. Twenty-four hours after the procedure, patients self-assessed pain levels according to the VAS table. The three groups returned after seven days so their postoperative acute reactions could be evaluated clinically. After six and twelve months, efficacy was evaluated. The self-assessed pain levels for group A and B were significantly lower than group C. The incidence of postoperative acute reactions after seven days for group A and B were significantly lower than those of group C. The effective rates after six and twelve months did not differ among these groups. The single-visit root canal treatment with a nickel-titanium rotary instrument combined with ultrasonic irrigation for elderly patients with chronic periapical periodontitis achieved short and long term efficacy and stability.
In this paper, in pursuit of enhancing the spectral efficiency and reliability of transmission in multiple-input multiple-output (MIMO) communication system, a new design method, named as the generalization of quadrature index modulation (GQIM), is proposed. In GQIM system, the key and vector indications are exploited by the design of the transmitted spatial vector (TSV). Also, the transmit diversity gain by transmitting two versions produced by a three dimension (3D) symbol is achieved. More specifically, in our proposed GQIM system, an extended dimension signal constellation, so called extended 3D constellation (E3DC), is designed for the employment in the GQIM framework. Then, for achieving the transmit diversity gain, combing with the antenna indexes, the X -axis, Y -axis, Z -axis components of two versions of the E3D symbol are constructed into four spatial vectors that are considered as candidates of the real/imaginary part of a complex TSV. Furthermore, two possible TSVs are obtained by using two adders and two key controllers with two states of 1 and j. With the aid of the vector indication, one out of two possible TSVs is selected for transmission. Finally, the spectral efficiency and squared MED, the spatial index bits and computational complexity, the upper bound on the average bit error probability are analyzed.
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