Antimicrobial effect of endodontic solutions used as final irrigants on a dentine biofilm model.

AIM: To evaluate the residual biovolume of live bacterial cells, the mean biofilm thickness and the substratum coverage found in mixed biofilms treated with different endodontic irrigant solutions. METHODOLOGY: Twenty-five bovine dentine specimens were infected intraorally using a removable orthodontic device. Five samples were used for each irrigant solution: 2% chlorhexidine, 1% sodium hypochlorite (NaOCl), 10% citric acid, 17% EDTA and distilled water. The solutions were used for 5 min. The samples were stained using the Live/Dead technique and evaluated using a confocal microscope. Differences in the amount of total biovolume (µm(3)), number of surviving cells (µm(3)), mean biofilm thickness (µm) and substratum coverage (%) of the treated biofilms were determined using nonparametric statistical tests (P < 0.05). RESULTS: Similar values of biovolume total, biovolume of live subpopulations and substratum coverage were found in 2% chlorhexidine, 10% citric acid, 17% EDTA and distilled water-treated biofilms (P > 0.05). The lower values of the studied parameters were found in 1% NaOCl-treated dentine (P < 0.05) with the exception of the mean biofilm height criteria that did not reveal significant differences amongst the irrigant solutions (P > 0.05). CONCLUSIONS: One per cent sodium hypochlorite was the only irrigant that had a significant effect on biofilm viability and architecture.

Conventional and digital radiographic methods in the detection of simulated external root resorptions: a comparative study.

OBJECTIVES: The purpose of this study was to evaluate and to compare the efficacy of a conventional and a digital radiographic method in diagnosing simulated external root resorption cavities. METHODS: Human dry mandibles containing teeth were covered with bovine muscle slices in order to simulate the soft tissues. Nine teeth from each dental group were investigated. Three periapical radiographs of each tooth were taken in an orthoradial, mesioradial and distoradial aspect using conventional film (Insight Kodak F-speed; Eastman Kodak, Rochester, NY) and a digital sensor (DRS Gnatus System; Gnatus, Ribeirao Preto, Brasil). The teeth were extracted using a forceps and had 0.7 mm and 1.0 mm deep cavities prepared on their vestibular, mesial and distal surfaces at the cervical, middle and apical thirds. Following preparation, each tooth was replaced in its alveolus and new radiographs were taken. Three dental professionals, an endodontist, a radiologist and a general practioner, evaluated the images. RESULTS: A larger number of cavities (P<0.05) were detected by the digital method when compared with the conventional method, for all depths of lesions. CONCLUSIONS: The results of this study suggest that the digital radiographic method is more sensitive than conventional radiography to detect simulated external root resorption cavities.