Assessment of the Separation Incidence of Reciprocating WaveOne Files: A Prospective Clinical Study

Introduction

Despite metallurgical advancements in the nickel-titanium file manufacturing process, file separation remains a concern. The purpose of this prospective clinical study was to assess the separation incidence of the reciprocating WaveOne file (Dentsply Tulsa Dental Specialties, Tulsa, OK) when used to prepare root canals of posterior teeth.

Methods

File separation incidence was assessed over an 18-month period in which 4 experienced and calibrated endodontists performed conventional endodontic treatment on posterior teeth using the WaveOne file system. The separation incidence was determined based on both the number of teeth and the number of canals instrumented during this time period.

Results

A total of 2,215 canals (711 teeth) were treated. Three instruments (two 21.06 and one 25.08) separated during use and were deemed to be irretrievable. The overall instrument separation incidence in relation to the number of canals shaped was found to be 0.13% (0.42% teeth).

Conclusions

Based on the results of this study, the incidence of endodontic instrument separation when using the WaveOne reciprocating file was considerably low.     

A Continuing HIV Epidemic and Differential Patterns of HIV-STI Risk among MSM in Quito, Ecuador: An Urgent Need to Scale Up HIV Testing and Prevention

This study characterized the HIV epidemic among men who have sex with men (MSM) in Quito, Ecuador and contrasted risk patterns with other STI’s. 416 MSM ages 15 years and older were recruited using respondent-driven sampling in 2010–2011. Biological testing and a self-interview survey assessed HIV and STI infections and risk behaviors. Analysis incorporated recruiter-level variables and clustering adjustments to control for recruitment patterns. We identify high levels of HIV (11 %), HSV-2 (14 %) and active syphilis (5.5 %) infections, low levels of lifetime HIV testing (57 %), limited knowledge of HIV and STI’s (<48 %) and limited consistent condom use independent of partner type (<40 %). Sex work was associated with all infections while associations with residential location, how casual partners are met and other variables, varied. Scale-up of behavioral prevention and HIV testing is urgently needed. Interventions should target male sex workers and exploit differential patterns of HIV-STI risk to stay ahead of the epidemic.     

Laparoscopic limited liver resection decreases morbidity irrespective of the hepatic segment resected

Objectives

The laparoscopic approach is widely used in abdominal surgery. However, the benefits of laparoscopy in liver surgery have hitherto been insufficiently established. This study sought to investigate these benefits and, in particular, to establish whether or not the laparoscopic approach is beneficial in patients with lesions involving the posterosuperior segments of the liver.

Methods

Outcomes in a cohort of patients undergoing mostly minor hepatectomy (50 laparoscopic and 52 open surgery procedures) between January 2000 and December 2010 at the University Clinic of Navarra were analysed. The two groups displayed similar clinical characteristics.

Results

Patients submitted to laparoscopic liver resection (LLR) had a lower risk for complications [odds ratio (OR) = 0.24, 95% confidence interval (CI) 0.07–0.74; P = 0.013] and shorter hospital stay (OR = 0.08, 95% CI 0.02–0.27; P < 0.001) independently of the presence of classical risk factors for complications. In the cohort of patients with lesions involving posterosuperior liver segments (20 laparoscopic, 21 open procedures), LLR was associated with significantly fewer complications (OR = 0.16, 95% CI 0.04–0.71) and a lower risk for a long hospital stay (OR = 0.1, 95% CI 0.02–0.43).

Conclusions

This study confirms that the laparoscopic approach to hepatic resection decreases the risk for post-surgical complications and lengthy hospitalization in patients undergoing minor liver resections. This beneficial effect is observed even in patients with lesions located in segments that require technically difficult resections.     

Assessment of the corneal collagen organization after chemical burn using second harmonic generation microscopy

The organization of the corneal stoma is modified due to different factors, including pathology, surgery or external damage. Here the changes in the organization of the corneal collagen fibers during natural healing after chemical burn are investigated using second harmonic generation (SHG) imaging. Moreover, the structure tensor (ST) was used as an objective tool for morphological analyses at different time points after burn (up to 6 months). Unlike control corneas that showed a regular distribution, the collagen pattern at 1 month of burn presented a non-organized arrangement. SHG signal levels noticeably decreased and individual fibers were hardly visible. Over time, the healing process led to a progressive re-organization of the fibers that could be quantified through the ST. At 6 months, the stroma distribution reached values similar to those of control eyes and a dominant direction of the fibers re-appeared. The present results show that SHG microscopy imaging combined with the ST method is able to objectively monitor the temporal regeneration of the corneal organization after chemical burn. Future implementations of this approach into clinically adapted devices would help to diagnose and quantify corneal changes, not only due to chemical damages, but also as a result of disease or surgical procedures.     

A parasitological survey of natural water springs and inhabitants of a tourist city in southeastern Brazil

The goals of this study were to investigate the occurrence of Cryptosporidium oocysts and Giardia cysts in main springs of Campos do Jord?o, an important tourist city, in Brazil and to gather the largest amount of parasitological data from autochthonous population that live in rural areas of this city. The membrane filtration technique followed by direct immunofluorescence assay was employed for concentration and visualization of waterborne protozoa. In the period between June 2003 and May 2004, the presence of at least one pathogenic protozoa was detected in 25.0% (3/12) of the springs studied, with mean concentrations ranging from 0.2 to 0.3 Cryptosporidium sp. oocysts and 0.07 to 0.1 Giardia sp. cysts/L. The coproparasitological investigation conducted in dwellers from two rural communities from this city revealed that 49.2% (91/185) of people had intestinal parasites. Among pathogenic protozoa, Cryptosporidium was the most prevalent species (8.1%) followed by Giardia duodenalis (5.9%), Entamoeba histolytica/Entamoeba dispar (2.7%), and Blastocystis hominis (2.2%). The most prevalent geohelminths were Ascaris lumbricoides (14.9%) and Trichuris trichiura (9.7%). This study demonstrated the contamination and the distribution of intestinal parasites, especially Cryptosporidium and Giardia species, in different springs of an important tourist city in Brazil, highlighting the need of monitoring natural water sources. The high prevalence of intestinal parasitosis detected in some specific populations of this city may function as a link of transmission of different intestinal parasitosis due to soil and water contamination, contributing to the maintenance of parasite life cycles. Therefore, the inclusion of consistent public health interventions with measures that include the protection of springs, the installation of minimum health infrastructure, and primary education of the population are widely necessary, aiming the control and prevention of parasite infections.     

Frequencies of chromosomal aberrations in rodents collected in the coal-field and tobacco culture region of Criciúma, south Brazil.

The present work has been accomplished in the basin of the Sang?o River (Criciúma, South Brazil), which receives the rejects from coal washing, mainly heavy metals. In the tobacco cultures at the river banks several agrotoxics are used. We tried to detect and estimate the possible action of this environmental pollution on rodents directly exposed to it through the study of chromosome aberration frequency in the bone marrow. The same methodology was applied to rodents collected from a nonpolluted area of the same state (Florianópolis, 190 km from Criciúma). The results obtained showed significant differences in total chromosome aberrations at the different sites. There is therefore a suggestion that this methodology could be applied to detect the action of environmental pollution on organisms.