The sealing ability of an epoxy resin root canal sealer used with five gutta-percha obturation techniques.

The purpose of the present study was to evaluate the apical sealing ability of an epoxy resin root canal sealer (AH-26) when used with different gutta-percha obturation techniques (i.e. cold lateral condensation, warm vertical condensation, hybrid condensation) and with Thermafil and Soft-Core obturators. Straight single-rooted teeth with mature apices were prepared according to the crown-down/step-back technique and divided in five groups of 45 teeth and one group of 12 control teeth. After root canal filling 15 teeth of each group were kept for 1 day, another 15 teeth for 1 week, and another 15 teeth for 4 months at 37 degrees C in vacutainers in 80% relative humidity. The 237 teeth were immersed in india ink for 90 hours, each root was split and sectioned longitudinally, and the maximum extent of leakage was measured using a stereomicroscope at x6 magnification. It became clear that leakage occurred whatever technique was combined with AH26 and that leakage increased with time. The amount of apical leakage and the number of leaking teeth in the Soft-Core obturator groups was significantly higher than all other 4 gutta-percha obturation techniques combined with AH26. In this respect, the hybrid gutta-percha condensation technique turned out to be superior to the four other condensation techniques.

Periapical health related to the quality of root canal treatment in a Belgian population.

AIM: The aim of this study was to collect data on the prevalence and technical standard of root canal treatment as well as the prevalence of apical periodontitis in Belgium. METHODOLOGY: The panoramic radiographs of 206 Belgian adults attending the Dental School of the University Hospital of Gent were examined for endodontic treatment, periapical conditions and coronal restorations. RESULTS: Of the 4617 teeth examined, 6.8% were endodontically treated. Periapical radiolucencies were found in 6.6% of all teeth and in 40.4% of the endodontically treated teeth. More than half of the root-filled teeth (56.7%) were scored inadequate on the basis of a criterion evaluating the level of the root canal filling. CONCLUSION: The endodontic treatment need of this Belgian subpopulation was great and the technical standard of root canal treatment disappointing. The findings indicate that there is still a substantial need for postgraduate endodontic education in Belgium and a need for specialists in endodontology.

Accuracy of four electronic apex locators: an in vitro evaluation.

In the present study, the accuracy and operator dependency of four electronic canal length measuring devices (Apex Finder AFA Model 7005, Apex-Finder, Neosono Ultima EZ and Apit 2) were compared under a set of specified conditions. The electronic apex locators were tested in unflared dry, flared wet and flared dry canals, and in a gelatin as well as in a sodium hypochlorite sponge model. Fifteen extracted single-canaled teeth were selected. The differences between canal lengths obtained by the electronic apex locators and actual canal lengths were scored. Only the Apex-Finder was found to be unreliable (measurements higher than +/- 0.5 mm from the apical foramen). This device was also found to be particularly dependent on operator. A ranking based on a precision of +/- 0.1 mm from the apical foramen showed the Apex Finder AFA Model 7005 to be the most accurate. Early coronal flaring did not ensure better or more precise readings. The gelatin model was evaluated to be more suitable for testing electronic apex locators in vitro than the sodium hypochlorite model.

The distribution of oestrogen and progesterone receptors in the human endometrial basal and functional layer during the normal menstrual cycle. An immunocytochemical study.

The distribution of oestrogen and progesterone receptors in the human endometrial basal and functional layer during the normal menstrual cycle was investigated by means of an immunocytochemical technique. A cyclic pattern of receptor distribution was observed. The highest concentration of hormone receptors was observed in the basal layer, in accordance with the idea that this layer is the source of endometrial regeneration.

Topographical distribution of oestrogen and progesterone receptors in the human endometrium and fallopian tube. An immunocytochemical study.

The topographical distribution of oestrogen and progesterone receptors in the human endometrium and Fallopian tube was investigated by an immunocytochemical technique. A gradient of positively stained cells was observed: the highest oestrogen and progesterone receptor content was noted in the fundal part of the uterine cavity and the ampullar region of the Fallopian tube. The observed gradient is in keeping with biological and pathological events that occur in the human mullerian tract, e.g. fecundation, implantation and carcinogenesis.

Circannual plasma androgen levels in free-living male great tits (Parus major major L.).

Seasonal variations of plasma androgen levels in free-living adult and juvenile male Great Tits (Parus major major L.) were measured by radioimmunoassay over a period of 5 years. In 4 of the 5 years a peak of androgen concentrations was observed during the breeding season (in 1 year during the prebreeding season, followed by a nadir during winter. Besides these circannual fluctuations, considerable variations in plasma androgen levels between comparable behavioral periods of successive years were noticed (187 to 18.5 ng/dl during the breeding season and 86 to 16 ng/dl during winter). No relationship was found between these variations and possible causative factors such as age and origin of the birds and the time of trapping and blood sampling during the day. The large between year variations in androgen levels may be caused by changes in the birds' environment including density of the population and the availability of food. Additional data are required to test this hypothesis.