ABSTRACT
El objetivo de este trabajo fue evaluar el efecto de soluciones de irrigación endodónticas solas y combinadas sobre iones calcio y fosfato de la dentina radicular ex vivo. Se emplearon 56 discos de dentina obtenidos del tercio medio radicular de premolares inferiores unirradiculares extraídos por razones ortodóncicas. Los discos se dividieron al azar en 8 grupos (n=7). Grupo I: agua destilada (AD), Grupo II: hipoclorito de sodio (NaClO) 1 %, Grupo III: EDTA 17 %, Grupo IV: ácido maleico (AM) 5 %, Grupo V: ácido acético (AA) 5 %, Grupo VI: EDTA 17 % + NaClO 1 %, Grupo VII: AM 5 % + NaClO 1 %, Grupo VIII: AA 5 % + NaClO 1 %. Los segmentos de dentina permanecieron en contacto a 37° C durante 5 min y 2,5 minutos en cada solución cuando se usaron en forma sucesiva. Se determinó la concentración de iones calcio de las soluciones mediante espectrometría de absorción atómica y la concentración de iones fosfatos mediante colorimetría (Wienner Lab.). Los resultados se expresaron en mg/ml/gr de tejido. Para el análisis estadístico se utilizó ANOVA y Test de Tukey. AA 5 % y EDTA 17 % se comportaron de manera similar utilizados solos durante 5 minutos, NaClO 1 % no mostró diferencias con el AD. AM 5 % eliminó significativamente más calcio y fosfato que todos los grupos. Todas las soluciones desmineralizaron la dentina, pero AM 5 % durante 5 min fue la solución que más afectó el componente inorgánico de la dentina.
The aim of the present study was to evaluate ex vivo irrigating solutions effect under calcium and phosphates dentin ions, using them alone and combined. In this study 56 dentin discs where used. They were obtained from middle third of mandibular single-root premolars extracted for orthodontics reasons. Discs were randomly divided into 8 groups (n:7). Group I: Distilled water (DW), Group II: 1 % sodium hypochlorite (NaOCl), Group III: 17 % EDTA, Group IV: 5 % maleic acid (MA), Group V: 5 % acetic acid (AA), Group VI: 17 % EDTA + 1 % NaOCl, Group VII: 5 % MA + 1 % NaOCl, Group VIII: 5 % AA + 1 % NaOCl. Dentin segments were kept in contact with irrigating solutions at 37°C for 5 minutes, when used alone, or for 2.5 minutes when used combined. After that, calcium ions (using absorption atomic spectrometry) and phosphorus ions (by colorimetry Wienner Lab.) were determined. Results were expressed in mg/ml/g tissue. Statistical analysis was performed by ANOVA and Tukey test. 5 % AA and 17 % EDTA eliminated similar concentrations of calcium and phosphates ions from dentin at 5 minutes exposure time, while 1 % NaOCl did not present statistical differences with control. 5 % MA eliminated significantly more calcium and phosphates ions than the rest of analyzed groups. Every tested solutions demineralized human dentin, but 5 % MA used for 5 minutes did it the most.
ABSTRACT
The aim of the present study was to compare the quality of preparation in curved and straight root canals employing 2 techniques, i.e. the step-back technique and the technique of Goerig, Michelich and Schultz. One hundred and thirty single-rooted human teeth were employed throughout. The walls of the root canals of these teeth were painted. Following instrumentation the roots were sectioned longitudinally. The sections were observed under a stereoscopic microscope SZ40 with a grid fitted in the eyepiece. The efficacy of instrumentation was evaluated using area of paint removed as the end-point. Statistical significance of the data was tested with the chi square test employing the Epi Info 5 software. There was no statistically significant difference between techniques for straight canals. The technique of Goerig, Michelich and Schultz was more effective than the step-back technique in the apical third of curved canals.