Glucose reactivity with filling materials as a limitation for using the glucose leakage model

Aim To evaluate the reactivity of different endodontic materials and sealers with glucose and to asses the reliability of the glucose leakage model in measuring penetration of glucose through these materials.Methodology Ten uniform discs (radius 5 mm, thickness 2 mm) were made of each of the following materials: Portland cement, MTA (grey and white), sealer 26, calcium sulphate, calcium hydroxide [Ca(OH)(2)], AH26,Epiphany, Resilon, gutta-percha and dentine. After storing the discs for 1 week at 37 degrees C and humid conditions, they were immersed in 0.2 mg mL(-1) glucose solution in a test tube. The concentration of glucose was evaluated using an enzymatic reaction after 1 week. Statistical analysis was performed with the ANOVA and Dunnett tests at a significant level of P < 0.05.Results Portland cement, MTA, Ca(OH)(2) and sealer 26 reduced the concentration in the test tube of glucose significantly after 1 week (P < 0.05). Calcium sulphate reduced the concentration of glucose, but the difference in concentrations was not significant (P = 0.054).Conclusions Portland cement, MTA, Ca(OH)(2) and sealer 26 react with a 0.2 mg mL(-1) glucose solution. Therefore, these materials should not be evaluated for sealing ability with the glucose leakage model.

Microbial leakage of MTA, Portland cement, Sealapex and zinc oxide-eugenol as root-end filling materials

Objective: The aim of this study was to compare the microbial leakage of mineral trioxide aggregate (MTA), Portland cement (PC), Sealapex and zinc oxide-eugenol (ZOE) as root-end filling materials.Study design: An in vitro microbial leakage test (MLT) with a split chamber was used in this study. A mixture of facultative bacteria and one yeast (S. aureus + E. faecalis + P. aeruginosa + B. subtilis + C. albicans) was placed in the upper chamber and it could only reach the lower chamber containing Brain Heart Infusion broth by way of leakage through the root-end filling. Microbial leakage was observed daily for 60 days. Sixty maxillary anterior human teeth were randomly assigned to different groups - MTA and PC (gray and white), Sealapex + zinc oxide and ZOE, control groups and subgroups to evaluate the influence of EDTA for smear layer removal. These materials were further evaluated by an agar diffusion test (ADT) to verify their antimicrobial efficacy. Data were analyzed statistically by Kruskal-Wallis and Mann-Whitney test.Results: In the MLT, Sealapex + zinc oxide and ZOE did not show evidence of microbial leakage over the 60-day experimental period. The other materials showed leakage from the 15th day. The presence of smear layer influenced microbial leakage. Microbial inhibition zones were not observed in all samples tested by ADT.Conclusion: Sealapex + zinc oxide and ZOE did not show microbial leakage over the experimental period, whereas it was verified within 15 to 45 days in MTA and Portland cement.

Agreement between direct, oscillometric and Doppler ultrasound blood pressures using three different cuff positions in anesthetized dogs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Collagen and reticular fibers in left ventricular muscle in diabetic rats: Physical exercise prevents its changes?

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Coronary perfusion pressure as a determinant of ventricular performance

The results observed in this work support the view that coronary perfusion pressure affects ventricular performance independently of metabolic effects; a mechanism operating in beat-to-beat regulation is proposed.

Influência da elevaçáo transitória e da elevaçáo sustentada da pressáo arterial sobre a primeira derivada temporal da pressáo ventricular.

PURPOSE--To analyze the influence of transient and sustained elevations of arterial pressure (AP) on the rate of rise of the left ventricular pressure (dp/dt). METHODS--Thirteen anesthetized, thoracotomized and mechanically ventilated dogs, submitted to pharmacological autonomic block (oxprenolol-3 mg/kg plus atropine-0.5 mg/kg). The AP elevation was obtained by mechanical constriction of the descending thoracic aorta. Two protocols were applied to all animals: Transient Arterial Hypertension (TAH) and Sustained Arterial Hypertension (SAH) and the following variables were evaluated: heart rate (HR), systolic (LVSP) and end diastolic (LVEDP) left ventricular pressure and dp/dt. In TAH the variables were analyzed in the basal condition (To) and at the maximal value of AP attained during the transient pressure elevation (TM). In the protocol SAH the variables were evaluated in the conditions: Control (Ho), hypertension 1 (H1) and hypertension 2 (H2). RESULTS--Considering all conditions, there were no significant differences among the values of HR. In the protocol TAH, the LVSP varied from 133 +/- 22 mmHg to 180 +/- 27 mmHg, whereas in SAH the values of LVSP were as follow: HO = 129 +/- 25 mmHg; H1 = 152 = 23 mmHg; H2 = 182 +/- 24 mmHg. LVEDP changed in both protocols: To = 7 +/- 2 mmHg; TM = 13 +/- 2 mmHg (p < 0.05); Ho = 7 +/- 2 mmHg; H1 = 10 +/- 2 mmHg; H2 = 14 +/- 3 mmHg (p < 0.05). During TAH there was no difference between the values of dp/dt (To = 3.303 +/- 598 mmHg/s; TM = 3.350 +/- 653 mmHg/s; p > 0.05), however, there were increases of the dp/dt during SAH (Ho = 3.233 +/- 576 mmHg/s; H1 = 3.831 +/- 667 mmHg/s; H1 = 4.594 +/- 833 mmHg/2; p < 0.05). CONCLUSION--The values of dp/dt are not influenced by transient elevation of AP. Sustained increase of AP activates cardiac adjustments, which results in elevation of dp/dt, by stimulation of contractile state. Probably, the inotropic intervention mechanism is the length dependent activation due to the Frank-Starling mechanism.

Apical leakage after root canal filling with an experimental calcium hydroxide gutta-percha point

This study was an in vitro analysis of the apical seal of root canals filled with an experimental calcium hydroxide gutta-percha point. One hundred and ten recently extracted human permanent teeth with a single root were used. The root canals were biomechanically prepared, and some received a dressing of calcium hydroxide for 7 days. Root canals not dressed were filled by the lateral condensation technique with either regular gutta-percha or calcium hydroxide gutta-percha points. The dressed root canals were filled with the same sealers and regular gutta-percha points. The specimens were placed into a 2% methylene blue dye solution under vacuum, and the apical leakage was linearly evaluated. The experimental groups with calcium hydroxide dressing and the one with calcium hydroxide gutta-percha points exhibited significantly (p < 0.05) less leakage than the groups filled with regular gutta-percha points. The results obtained indicated that calcium hydroxide guttapercha points produced an improvement in the apical sealing quality of the root canal filling. Copyright © 1996 by The American Association of Endodontists.