Microfiltración apical in vitro causada por las técnicas de obturación con cono único, System B y condensación lateral clásica / In vitro apical microleakage causade by single-cone, System B and cold lateral condensation obturation techniques

La obtención de un sellado hermético en la obturación del conducto radicular es una etapa coadyuvante del éxito endodóntico. Objetivo: Comparar la microfi ltración apical in vitro, calidad de relleno y presencia de espacios vacíos en conductos radiculares obturados con los métodos de obturación cono único, condensación lateral clásica y System B. Material y métodos: Noventa raíces mesiales de molares inferiores fueron instrumentados con ProTaper a un calibre F3 y asignados aleatoriamente para su obturación a tres grupos (n = 30 raíces), grupo 1: condensación lateral clásica con gutapercha #30.02, grupo 2: cono único con gutapercha F3 y grupo 3: System B con gutapercha #30.02; en todas las técnicas se usó una mezcla de óxido de zinc eugenol como sellador.Obturados los conductos las muestras se sumergieron en azul de metileno al 0.5 por ciento, se centrifugaron a 3,200 rpm durante cinco minutos, se diafanizarony se llevaron al microscopio estereoscópico a 12.5x para la mediciónde microfi ltración apical, calidad de relleno y presencia de espacios vacíospor un observador calibrado. Resultados: No se encontraron diferencias significativas en la microfi ltración apical entre el grupo de condensación lateral clásica y System B (p > 0.05) siendo el cono único la técnica que presenta mayor fi ltración. La técnica que ofrece la menor cantidad de espacios vacíos y mejor calidad de relleno es System B. Conclusiones:El método System B y condensación lateral clásica dejan una baja microfiltración apical y adecuada calidad de relleno comparada con la que sepresenta con cono único utilizando como sellador óxido de zinc eugenol...

Marginal adaptation of zirconium dioxide copings: influence of the CAD/CAM system and the finish line design.

STATEMENT OF PROBLEM: Marginal adaptation is essential for the long-term success of dental restorations. Studies comparing the marginal gaps of computer-aided design/computer-aided manufacturing (CAD/CAM) restorations made from conventional and digital impressions are limited. PURPOSE: The purpose of this study was to evaluate the marginal adaptation of zirconium dioxide copings made with 2 different CAD/CAM systems, the Lava All-Ceramic System (scanning definitive dies made with conventional impressions) and the Lava Chairside Oral Scanner (scanning directly from the prepared tooth). In addition, the influences of 2 different finish line configurations were also compared. MATERIAL AND METHODS: Forty human molar teeth were prepared to receive complete crowns. Twenty were prepared with a 90-degree round shoulder and the other 20 with a 45-degree chamfer finish line. Zirconium dioxide copings were fabricated by using CAD/CAM technology. The specimens were randomized; they included 10 teeth with round shoulder and 10 with chamfer finish lines with the Lava All-Ceramic System, and 10 teeth with round shoulder and 10 with chamfer finish lines with the Lava Chairside Oral Scanner. The marginal gaps were measured at 5 points on each side with stereomicroscopy at 40× magnification. Data were analyzed with 2-way ANOVA (α=.05). RESULTS: The mean values of the measured marginal gap for the round shoulder group were 52.66 µm with the Lava All-Ceramic System and 14.98 µm with the Lava Chairside Oral Scanner. The mean values for the chamfer group were 64.06 µm for the Lava All-Ceramic System and 18.45 µm for the Lava Chairside Oral Scanner. Differences were identified when the marginal gaps between the specimens with different CAD/CAM systems were compared. However, differences in the finish line design were identified only between the round shoulder and chamfer with the Lava All-Ceramic System. CONCLUSIONS: Restorations fabricated with the Lava Chairside Oral Scanner displayed smaller marginal gaps than those made with the Lava All-Ceramic System. Nevertheless, all marginal gaps were within the range of clinical acceptability for both groups.