Comparison of working length determination with radiographs and two electronic apex locators.

AIM: To evaluate the accuracy of the Root ZX and Elements-Diagnostic electronic apex locators when compared with radiographs for locating the canal terminus or minor foramen. METHODOLOGY: The canal terminus of 482 canals in 160 maxillary and mandibular teeth was located in vivo with both locators and radiographically. After extraction, the actual location of the minor foramen was determined visually and with magnification. A paired samples t-test, chi-square test and a repeated measure anova at the 0.05 level of significance were used to determine differences between the groups. RESULTS: The Root ZX located the minor foramen correctly 68% of the time in anterior and premolar teeth, and 58% of the time in molar teeth. The Elements-Diagnostic located the minor foramen correctly 58% of the time in anterior and premolar teeth and 49% of the time in molar teeth. Radiographs located the minor foramen correctly 20% of the time in anterior and premolar teeth and 11% of the time in molar teeth. There was no statistically significant difference between the two locators, but there was a significant difference between them and radiographs. For all teeth, the measurements made by the apex locators were within +/-0.5 mm of the minor foramen 100% of the time, whereas for the radiographs, the measurements were within this range only 15% of the time. This difference was significant (P = 0.05). CONCLUSION: Measuring the location of the minor foramen using the two apex locators was more accurate than radiographs and would reduce the risk of instrumenting and filling beyond the apical foramen.

Anencefalia: presentación de un caso clínico / Anencephaly: a clinical case

La anencefalia es una malformación del sistema nervioso, causado por la falla del cierre del neuroporo anterior durante la embriogénesis. Su incidencia es de 1 en 1.000 embarazos en Estados Unidos. Los recién nacidos con anencefalia generalmente sobreviven sólo pocas horas o días, y excepcionalmente se han descrito casos de sobrevida de algunas semanas. Existen numeroso estudios que sugieren la existencia de factores genéticos y ambientales en la génesis de este trastorno, por ejemplo, mutaciones en el gen que codifica la enzima metilentetrahidrofolato reductasa, elevados niveles plasmáticos de homocisteína y bajos de folato en madres de niños con defectos del tubo neural y factores ambientales diversos. La mayoria de los casos son diagnosticados mediante ultrasonografía precozmente durante el embarazo (antes de las 20 semanas). Se presenta un caso clínico de recién nacido con anencefalia, en el Hospital de Salamanca, que tuvo una sobrevida excepcionalmente prolongada y se revisa el tema

Total arsenic, lead, cadmium, copper, and zinc in some salt rivers in the northern Andes of Antofagasta, Chile.

The pre-Andes water in the region of Antofagasta is the main drinking and irrigation water source for approximately 3000 Atacameña (indigenous) people. The concentration for soluble elements (filtration in field through a 0.45-microm filter) was: Cd < 0.1 ng/ml; Pb < 0.5 ng/ml; and Zn and Cu between 1 and 10 ng/ml. In particulate material the concentrations were: for Cd < 0.1 ng/ml; for Pb < 0.3 ng/ml; and for Zn and Cu less than 1 ng/ml. The total content of these elements is far below the international recommendations (WHO) and the national standards (N. Ch. 1333 mod. 1987 and 409-1 of 1984). On the other hand, in some rivers a very high arsenic concentration was found (up to 3000 ng/ml) which exceed more than 50 times the national standard. In order to verify the analytical results, inter-laboratory and comparison with different determination methods have been done.