Abstract: Chemomechanical preparation is intended to clean, disinfect, and shape the root canal. This step is of utmost importance during treatment of infected teeth with apical periodontitis, because treatment outcome depends on how effectively the clinician eliminates bacteria, their products, and necrotic tissue that would serve as substrate for bacterial regrowth. Nonetheless, curvatures and complex internal anatomical variations of the root canal system can pose a high degree of difficulty in reaching these goals. In infected teeth, bacteria may persist not only in difficult-to-reach areas such as isthmuses, ramifications, dentinal tubules, and recesses from C-shaped or oval/flattened canals, but also in areas of the main canal wall that remain untouched by instruments. If bacteria withstand chemomechanical procedures, there is an augmented risk for post-treatment apical periodontitis. This article discloses the reasons why some areas remain unprepared by instruments and discusses strategies to circumvent this issue and enhance infection control during endodontic treatment/retreatment of teeth with apical periodontitis.

Evidências indicam que pacientes diabéticos são mais significativamente afetados por problemas de origem endodôntica. Este estudo avaliou radiográfica e histologicamente o desenvolvimento de inflamação perirradicular em ratos controle e diabéticos depois da indução de infecção pulpar. As polpas dos primeiros molares inferiores de ratos normais ou diabéticos foram expostas e deixadas em contato com a cavidade oral por 21 e 40 dias. Em seguida, os animais foram sacrificados, as mandíbulas removidas cirurgicamente, fixadas em formalina e depois radiografadas em posição padronizada. As imagens radiográficas das lesões perirradiculares foram escaneadas e as imagens computadorizadas avaliadas quanto à área total das lesões usando software específico. Espécimes representativos foram preparados também para análise histológica. A análise radiográfica revelou que os ratos diabéticos apresentaram lesões periradiculares significativamente maiores quando comparados com os ratos normais, independentemente do período experimental (p<0.05). O exame histológico de espécimes representativos revelou lesões perirradiculares mais extensas e com exsudato inlflamatório severo no grupo de ratos diabéticos quando comparado com o grupo controle. Os dados deste estudo indicam que ratos diabéticos podem ser mais propensos a desenvolver lesões perirradiculares extensas, possivelmente devido à diminuição da capacidade de defesa contra patógenos microbianos.

Evidence suggests that diabetic patients are more significantly affected by problems of endodontic origin. This study sought to radiographically and histologically examine the development of periradicular inflammation in control and in diabetic rats after induction of pulpal infection. The pulps of the mandibular first molars of normal and streptozotocin-induced diabetic rats were exposed and left in contact with their oral cavities for 21 and 40 days. Afterwards, the animals were sacrificed, the mandibles were surgically removed, fixed in formalin and then radiographed in a standardized position. The radiographic images of the periradicular lesions were scanned and computerized images were evaluated for the total area of the lesions using a specific software. Representative specimens were also prepared for histopathological analysis. Radiographic analysis revealed that diabetic rats presented significantly larger periradicular lesions when compared with control rats, regardless of the experimental period (p<0.05). Histopathological examination of representative specimens revealed larger periradicular lesions and more severe inflammatory exudate in the group of diabetic rats when compared with the control group. Data from the present study indicated that diabetic rats can be more prone to develop large periradicular lesions, possibly due to reduction in the defense ability against microbial pathogens.

Substâncias e materiais utilizados na terapia endodôntica entram em íntimo contato com os tecidos perirradiculares via forame apical e foraminas e, em decorrência disto, deveriam idealmente possuir as seguintes características: biocompatibilidade e ausência de mutagenicidade. Existem poucos estudos avaliando o potencial genotóxico e mutagênico de substâncias e materiais utilizados em Endodontia. Este estudo avaliou os efeitos citotóxicos, genotóxicos e mutagênicos diretos de várias substâncias e materiais utilizados em diferentes etapas do tratamento endodôntico. Para isto, dois sistemas procarióticos foram usados: o SOS chromotest e o teste de Ames. Metabolização com fração S9 não foi realizada, uma vez que tencionou-se avaliar os efeitos diretos das substâncias e materiais. Os resultados demonstraram que algumas substâncias e materiais foram citotóxicos e/ou genotóxicos no SOS chromotest. Formocresol foi a única substância testada a apresentar efeitos genotóxicos severos sobre as cepas teste. Todavia, nenhum dos materiais ou substâncias avaliados apresentou mutagenicidade no teste de Ames.

Substances and materials used in endodontic therapy come into close contact with the periradicular tissues via apical foramen and foramina. Consequently, they should possess biocompatibility. There are currently few studies describing the genotoxic and mutagenic potentials of substances and materials used in endodontics. The purpose of this study was to evaluate the direct genotoxic and mutagenic properties of several substances and materials used in different phases of the endodontic treatment. For this intent, two prokaryotic test systems were used: the SOS chromotest and the Ames test. No metabolization with S9 was investigated, since only the direct effects of the substances and materials were surveyed. Most of the substances and materials tested presented mild to moderate cytotoxicity and genotoxicity as revealed by the SOS chromotest. Formocresol was the only tested substance to present severe genotoxicity to the tester bacterial strains. However, no substance or material tested showed direct mutagenicity as revealed by the Ames test.