Effect of Reciprocating Systems and Working Lengths on Apical Microcrack Development: a micro-CT Study

Abstract The objective of this study was to evaluate the effect of root canal preparation with single-file reciprocating systems at different working lengths on the development of apical microcracks using micro-computed tomographic (micro-CT) imaging. Forty extracted human mandibular incisors were randomly assigned to 4 groups (n=10) according to the systems and working length used to prepare the root canals: Group A - WaveOne Gold at apical foramen (AF), Group B - WaveOne Gold 1 mm short of the AF (AF-1 mm), Group C - Unicone (AF) and Group D - Unicone (AF-1 mm). Micro-CT scanning was performed before and after root canal preparation at an isotropic resolution of 14 µm. Then, three examiners assessed the cross-sectional images generated to detect microcracks in the apical portion of the roots. Apical microcracks were visualized in 3, 1, 1, and 3 specimens in groups A, B, C, and D, respectively. All these microcracks observed after root canal preparation already existed prior to instrumentation, and no new apical microcrack was detected. For all groups, the number of slices presenting microcracks after root canal preparation was the same as before canal preparation. Root canal preparation with WaveOne Gold and Unicone, regardless of the working length, was not associated with apical microcrack formation.

Resumo O objetivo deste estudo foi avaliar o efeito da instrumentação de canais radiculares utilizando sistemas reciprocantes de lima única em diferentes comprimentos de trabalho sobre o desenvolvimento de microfissuras apicais utilizando imagens de microtomografia computadorizada (micro-CT). Quarenta incisivos inferiores humanos extraídos foram distribuídos aleatoriamente em 4 grupos (n=10) de acordo com os sistemas e comprimentos de trabalho utilizados para preparar os canais radiculares: Grupo A - WaveOne Gold no forame apical (FA), Grupo B - WaveOne Gold 1 mm aquém do FA (FA-1 mm), Grupo C - Unicone (FA) e grupo D - Unicone (FA-1 mm). Escaneamentos de micro-CT foram realizados antes e após o preparo dos canais a uma resolução isotrópica de 14 μm. Em seguida, três examinadores avaliaram as imagens de secção transversal geradas para detectar microfissuras na porção apical das raízes. Microfissuras apicais foram visualizadas em 3, 1, 1 e 3 espécimes nos grupos A, B, C e D, respectivamente. Todas essas microfissuras observadas após o preparo dos canais radiculares já existiam antes da instrumentação e não foi detectada nenhuma nova microfissura apical. Para todos os grupos, o número de cortes apresentando microfissuras após o preparo dos canais radiculares foi o mesmo verificado antes do preparo dos canais. A instrumentação de canais radiculares utilizando WaveOne Gold e Unicone, independentemente do comprimento de trabalho, não foi associada à formação de microfissuras apicais.

Prevalence of endodontic diseases: an epidemiological evaluation in a Brazilian subpopulation

Aim: To determine the prevalence of pulp and periradicular diseases in a Brazilian subpopulation, correlating the prevalence with sex, age and most affected teeth. Methods: Data collected from medical records of patients treated at the Clinic of Specialization in Endodontics of the Federal University of Pernambuco between 2003 and 2010. The following variables were recorded for each patient: sex, age, affected teeth and diagnosed endodontic disease. Using Pearson's chi-square and Fisher's exact tests, the collected data analysis was set at a 5% significance level. Results: From all the treated teeth, 57% were diagnosed with pulp diseases, with the symptomatic irreversible pulpitis being the most prevalent (46.3%), while among the diagnosed periradicular diseases (43%), chronic apical periodontitis was the most prevalent (81%). Pulp diseases were detected in men and women in an unequal mode (p=0.008). Subjects under 40 years old had higher prevalence of pulp disease (p=0.286), and patients over 50 years were most affected by periradicular diseases (p=0.439). Maxillary incisors and mandibular first molars were the most affected teeth by endodontic diseases. Conclusions: In the evaluated subpopulation, the endodontic diseases were more prevalente in the maxillary incisive, affected indiscriminately individuals of different age groups and chronic apical periodontitis was the most prevalent diagnosed disease (Au)

Analysis of anatomical landmarks of the mandibular interforaminal region using CBCT in a Brazilian population

Aim: To evaluate the position, presence, appearance and extent of various anatomical landmarks in the mandibular interforaminal region of Brazilian patients using cone-beam computed tomography (CBCT). Methods: A total of 142 CBCT examinations were analyzed to determine the most common location of the mental foramen (MF), the presence and extent of the anterior loop (AL) of the inferior alveolar nerve, and the appearance and length of the incisive canal (IC). The presence of sexual dimorphism and differences with relation to the left and right sides were also evaluated. Results: Most of the MF (45.5%) was located below the second premolar. The AL and the IC were observed in 18.9 and 96.5% of the images respectively. The average length of AL and IC was 3.14±1.25 mm and 13.68±5.94 mm respectively. No significant differences (p>0.05) between genders or left and right sides were observed for all evaluated parameters. Conclusions: The most common location of the MF, the high rate of visualization of the IC and the occasional presence of AL in the studied Brazilian population demonstrate the importance of using three-dimensional images of the mandibular anterior region, allowing proper surgical planning and preventing injury to the neurovascular bundle.

In Vitro antimicrobial photoinactivation with methylene blue in different microorganisms

AIM: To evaluate the in vitro antimicrobial effects of photodynamic therapy (PDT). METHODS: The microorganism indicators were: Candida albicans, Pseudomonas aeruginosa,Enterococcus faecalis and Staphylococcus aureus. A microbial pool was prepared (10 8 cells/mL), from which aliquots were transferred to culture plates for carrying out the PDT using methylene blue (50 µM) and low-power laser (660 nm, 100 mW and 9 J).The effect of methylene blue alone, low power laser and the absence of treatments were evaluated. Then, aliquots of 1 µL were plated in a media culture, the number of colony forming units (CFU/mL) was obtained and the data submitted to the F test (ANOVA) with Tamhane's comparisons. RESULTS: The laser radiation in the presence of methylene blue was able to eliminate 74.90% of C. albicans, 72.41% of P. aeruginosa, 96.44% of E. faecalis and 95.42% of S. aureus, thus statistically significant differences were found among the groups (p<0.001). CONCLUSIONS: PDT was effective in reducing the number of viable cells in the studiedmicroorganisms, especially E. faecalis and S. aureus.

Variation of length of styloid process / Variación de longitud del proceso estiloides

The styloid process is a bony projection that arises from the tympanic portion of the temporal bone, and its elongation is considered an anomaly that may be related to calcification of the stylohyoid and stylomandibular ligaments, which can trigger a series of symptoms that characterize the Eagle's syndrome. The objective of this study was to report three cases of elongated styloid process seen in human skulls, trying to alert the dentists in the knowledge of this disease in order to include it in their diagnosis, associated with atypical facial pain or in the oral cavity of to facilitate better treatment for these cases.

El proceso estiloides es una proyección ósea que tiene su origen en la porción timpánica del hueso temporal y su elongación es considerado una anomalía que puede relacionarse con la calcificación de los ligamentos estilohioídeo y estilomandibular, y de esta forma desarrollar una serie de síntomas que caracterizan al Síndrome de Eagle. El objetivo de este trabajo fue describir en tres cráneos humanos la elongación del proceso estiloides y dar a conocer al cirujano dentista esta anomalía, para que la incluya en su diagnóstico, cuando se éste presenta dolores atípicos de la cara o de la cavidad oral, y así facilitar el mejor tratamiento en estos casos.