Shaping the root canal system.

The speciality of endodontics encompasses numerous elements, but the use of a variety of instruments to shape root canal systems probably challenges the clinical time of practitioners more than any other. The aim of this article is to review some of the historic and contemporary approaches to this challenging practical objective.

The effect of stimulus intensity on response time and accuracy in dynamic, temporally constrained environments.

The ability to make accurate judgments and execute effective skilled movements under severe temporal constraints are fundamental to elite performance in a number of domains including sport, military combat, law enforcement, and medicine. In two experiments, we examine the effect of stimulus strength on response time and accuracy in a temporally constrained, real-world, decision-making task. Specifically, we examine the effect of low stimulus intensity (black) and high stimulus intensity (sequin) uniform designs, worn by teammates, to determine the effect of stimulus strength on the ability of soccer players to make rapid and accurate responses. In both field- and laboratory-based scenarios, professional soccer players viewed developing patterns of play and were required to make a penetrative pass to an attacking player. Significant differences in response accuracy between uniform designs were reported in laboratory- and field-based experiments. Response accuracy was significantly higher in the sequin compared with the black uniform condition. Response times only differed between uniform designs in the laboratory-based experiment. These findings extend the literature into a real-world environment and have significant implications for the design of clothing wear in a number of domains.

Advanced glycation end products cause epithelial-myofibroblast transdifferentiation via the receptor for advanced glycation end products (RAGE).

Tubulointerstitial disease, a prominent phenomenon in diabetic nephropathy, correlates with decline in renal function. The underlying pathogenic link between chronic hyperglycemia and the development of tubulointerstitial injury has not been fully elucidated, but myofibroblast formation represents a key step in the development of tubulointerstitial fibrosis. RAGE, the receptor for advanced glycation end products (AGEs), induces the expression of TGF-beta and other cytokines that are proposed to mediate the transdifferentiation of epithelial cells to form myofibroblasts. Here we report specific binding of (125)I-AGE-BSA to cell membranes prepared from a rat proximal tubule cell line and show that the binding site was RAGE. AGE exposure induced dose-dependent epithelial-myofibroblast transdifferentiation determined by morphological changes, de novo alpha smooth-muscle actin expression, and loss of epithelial E-cadherin staining. These effects could be blocked with neutralizing Ab's to RAGE or to TGF-beta. Transdifferentiation was also apparent in the proximal tubules of diabetic rats and in a renal biopsy from a patient with type 1 diabetes. The AGE cross-link breaker, phenyl-4,5-dimethylthiazolium bromide (ALT 711) reduced transdifferentiation in diabetic rats in association with reduced tubular AGE and TGF-beta expression. This study provides a novel mechanism to explain the development of tubulointerstitial disease in diabetic nephropathy and provides a new treatment target.

An in vitro investigation of coronal leakage with three gutta-percha backfilling techniques.

The aim of this study was to compare the backfilling capabilities of System B, Obtura II and Alphaseal. Forty-six lower premolar teeth were prepared chemomechanically and allocated to four experimental and two control groups. Ten were obturated using lateral condensation as a standard and 30 were obturated in the apical third using the System B. The latter 30 teeth were then backfilled using one of three techniques, System B, Obtura II or Alphaseal (n = 10 in each group). The remaining six teeth served as controls. Roots were radiographed from the proximal in order to evaluate voids and then placed in India ink for 65 h prior to being demineralized and rendered transparent, coronal leakage was quantified by linear measurement of ink penetration. No significant difference was found between the four groups with respect to the presence of voids radiographically (P < 0.05). The difference in leakage between the System B and Obtura II groups was not significant (P > 0.05). Both System B and Obtura II leaked significantly less than Alphaseal and lateral condensation (P < 0.001).