An assessment of the plastic Thermafil obturation technique. Part 3. The effect of post space preparation on the apical seal.

The effect of post space preparation on the apical seal of teeth roots treated with the plastic-cored Thermafil was studied in vitro. Single rooted teeth with mature apices were prepared chemomechanically and obturated with alpha-phase gutta-percha, Thermafil, on plastic core-carriers and sealer, Sealapex. The teeth were divided randomly into four groups of 18 teeth each. In two of the groups post space was prepared by hand using a Parapost drill (diam. 1.25 mm) after gutta-percha removal with Peeso reamers in a slow-speed handpiece, one group immediately after canal obturation and the other after storage in 100% relative humidity at 37 degrees C for 1 week; 5 mm of root filling was left intact. The time taken to remove the gutta-percha was recorded. Post space was not prepared in the control groups. Apical leakage was determined using black India ink. The teeth were demineralized, rendered transparent, and linear measurement of dye penetration was recorded. Results showed that there were no significant differences in leakage between any of the groups (P > 0.05). There was no statistically significant difference in the time required to remove the gutta-percha from the root canals in both groups (P < 0.05). It is concluded that under the conditions of this study post space preparation immediately after obturation, or after a delay of 1 week, does not affect the apical seal of Thermafil with plastic core-carriers.

Use of nuclear magnetic resonance imaging to show regression of hypertrophy with ramipril treatment.

Thirty-two patients with arterial hypertension (diastolic blood pressure greater than 95 mm Hg) were treated with ramipril for 3 months. The aim of the study was to achieve an effective decrease in blood pressure and demonstrate reliably and reproducibly that regression of left ventricular hypertrophy takes place with ramipril treatment. Nuclear magnetic resonance images and echocardiographic measurements of the left ventricle were therefore made before treatment started, 4 hours after the first dose, 14 days after the start of treatment and after 3 months of treatment. The thickness of the septum decreased from 19.57 to 15.20 mm on magnetic resonance scans and from 18.78 to 14.57 mm on echocardiograms. The values were reproduced 3 times at the same measuring point and means were calculated. The septum and posterior wall of the left ventricle were also measured at 3 different points. With negligible scatter, the values obtained were reproducible and the differences were highly significant (p = 0.001). A parallel decrease in blood pressure to levels 15% below baseline was also observed. The therapeutic aim of achieving diastolic blood pressure levels of less than or equal to 90 mm Hg was achieved in all patients. In addition to reducing the blood pressure significantly, the angiotensin converting enzyme inhibitor ramipril caused a significant regression of pathologic left ventricular hypertrophy, which was demonstrated clearly using magnetic resonance imaging and echocardiography.