The ability of three nickel-titanium mechanized systems to negotiate and shape MB2 canals in extracted maxillary first molars: a micro-computed tomographic study.

AIM: To evaluate the influence of three engine-driven NiTi file systems manufactured from different NiTi alloys for the preparation of second mesiobuccal (MB2) canals in extracted maxillary first molars using a micro-computed tomographic (micro-CT) scanner. METHODOLOGY: Thirty maxillary molars with two canals in the mesiobuccal root were selected and randomly divided into three groups (n = 10): Reciproc [REC; size 25, .08 taper; VDW, Munich, Germany], ProDesign R [PDR; size 25, .06 taper; Easy, Belo Horizonte, Brazil] and Mtwo [MO; size 25, .06 taper; VDW, Munich, Germany]. Before and after root canal preparation of the MB2 canal, the teeth were scanned using a micro-CT to evaluate canal transportation, centring ability, dentine thickness and volume change. The working time to achieve working length was also evaluated. All parameters were compared statistically using the Kruskal-Wallis and Dunn test for multiple comparisons, with a significance level of 5%. RESULTS: There was no significant difference amongst the groups regarding canal transportation and centring ability (P > 0.05). However, the PDR size 25, .06 taper group had significantly lower canal volume and volume of dentine removal compared with a MO size 25, .06 taper and REC size 25, .08 taper (P < 0.05). A root perforation was detected in MO size 25, .06 taper and REC size 25, .08 taper groups, respectively. Regarding the working time, the PDR size 25, .06 taper required a significantly longer time to achieve working length than MO size 25, .06 taper and REC size 25, .08 taper (P < 0.05). CONCLUSIONS: All NiTi systems had similar canal transportation, centring ability and increase in apical volume after preparation of MB2 canals. However, the PDR size 25, .06 taper had less volume of dentine removal, absence of root canal perforation and required a longer time to accomplish the root canal preparation.

Comparison of oral fluid collection methods for the molecular detection of hepatitis B virus.

BACKGROUND: This study aims to compare the efficiency of four oral fluid collection methods (Salivette, FTA Card, spitting and DNA-Sal) to detect HBV DNA by qualitative PCR. MATERIALS AND METHODS: Seventy-four individuals (32 HBV reactive and 42 with no HBV markers) donated serum and oral fluid. In-house qualitative PCR to detect HBV was used for both samples and commercial quantitative PCR for serum. RESULTS: HBV DNA was detected in all serum samples from HBV-infected individuals, and it was not detected in control group. HBV DNA from HBV group was detected in 17 samples collected with Salivette device, 16 samples collected by FTA Card device, 16 samples collected from spitting and 13 samples collected by DNA-Sal device. Samples that corresponded to a higher viral load in their paired serum sample could be detected using all oral fluid collection methods, but Salivette collection device yielded the largest numbers of positive samples and had a wide range of viral load that was detected. CONCLUSION: It was possible to detect HBV DNA using all devices tested, but higher number of positive samples was observed when samples were collected using Salivette device, which shows high concordance to viral load observed in the paired serum samples.

Simultaneous detection of hepatitis C virus antigen and antibodies in dried blood spots.

BACKGROUND: Enzyme immunoassays (EIA) designed to detect hepatitis C virus (HCV) core antigen and anti-HCV antibodies (HCV AgAb) simultaneously can improve the early detection of HCV infection when molecular diagnostic methods are not widely available. OBJECTIVES: To evaluate the suitability of dried blood spot (DBS) samples for detecting HCV AgAb using commercial EIAs. STUDY DESIGN: Paired serum and DBS samples were assayed using two commercial EIAs for HCV AgAb (Monolisa™ HCV AgAb ULTRA and Murex HCV AgAb). Manufacturer's recommendations were followed for sera while sample volume, incubation time and cut-off (CO) determination were evaluated for the DBS samples. The values of sensitivity, specificity, inter-rater agreement, detection limit, assay precision and stability of DBS samples at different conditions (22-26°C, 2-8°C and -20°C) were determined. RESULTS: It was necessary to increase the DBS sample volume fourfold compared to the sera samples to approximate the DBS Optical Density (OD) values to the sera OD values. Using ROC curve to recalculate CO values for the DBS samples, sensitivity was 97.5% for both EIAs, while the specificity was 99.71% for Monolisa™ HCV AgAb ULTRA and 95.95% for Murex HCV AgAb. Accurate testing results were obtained with DBS samples for 60 days at all conditions evaluated; storage at -20°C resulted in low OD variation. Both EIAs demonstrated the same limit of detection among DBS samples [estimated viral load of 3.1 International Units per millilitre (IU/mL)] and low OD value variability in repetitivity and reproducibility studies. CONCLUSION: DBS samples can be used for the detection of HCV AgAb by EIA as they present comparable performance characteristics and excellent stability among various storage conditions.

Dried blood spot samples: optimization of commercial EIAs for hepatitis C antibody detection and stability under different storage conditions.

This study was undertaken to optimize and compare the efficiency of two commercial EIAs for anti-HCV detection (HCV Ab Radim, Pomezzia, Italy and ETI-AB-HCVK-4 DiaSorin, Vercelli, Italy), in dried blood spot (DBS) samples. The long-term stability of anti-HCV on DBS samples stored at three environmental conditions was also evaluated at: 2-8 °C, 20-25 °C, and -20 °C. Paired DBS and serum samples were obtained from individuals with or without anti-HCV. The type of elution buffer, sample and conjugate volume, sample incubation time and cut-off values were evaluated. For both EIAs, a larger sample volume was used, and the cut-off value determined by the manufacturer was employed for Radim EIA; however, ROC curve analysis was used for the DiaSorin EIA. The sensitivity and specificity of Radim EIA on DBS were 97.5% and 99.5%, respectively, and of DiaSorin EIA were 88.9% and 98.9%, respectively. Accurate results were obtained for a period of 117 days using DBS samples stored at all storage conditions, but storage at -20 °C resulted in the lowest variation among the absorbance values. Both EIAs demonstrated the same limit of detection (until dilution of 1:10(4) with estimated viral load of 3.1 × 10(-1) UI/ml), but the Radim EIA was associated with the best performance because a low coefficient of variation was observed in the repetition and reproducibility studies. In conclusion, commercial EIAs can be optimized for anti-HCV detection in DBS samples that are extremely stable at different conditions for more than 100 days.

An evaluation of different saliva collection methods for detection of antibodies against hepatitis C virus (anti-HCV).

BACKGROUND: Saliva samples can be used as an alternative fluid for against hepatitis C virus (anti-HCV) detection owing to the ease of collection and excellent acceptability. This study was conducted to optimize a commercial enzyme immunoassay (EIA) to detect anti-HCV in saliva samples. METHODS: Ninety-six individuals donated paired serum and saliva samples that were obtained, using a commercial device (Salivette) and spitting into a sterile container. Initially, elution buffer for the Salivette samples, sample volume, incubation time and temperature, and two different anti-HCV EIAs were evaluated. Using the optimized assay, three methods for cut-off calculation were also evaluated. RESULTS: A 20-fold increase in the sample volume for both collection methods was needed. Moreover, the Radim assay was the most appropriate assay for anti-HCV detection in saliva samples, and the quality parameters were increased when a ROC curve was used to determine the cut-off value. Using this optimized assay, the sensitivities, specificities, accuracies, positive and negative predictive values were above 90% for saliva obtained using both the Salivette and spitting methods. Using this assay, discordant false-negative results were obtained for only two Salivette samples and five spitting samples. The concordance kappa was 93% for the Salivette method and 86.1% for the spitting method, demonstrating excellent performance. CONCLUSIONS: Saliva samples obtained for both methods can be employed for anti-HCV detection among HCV-infected or HCV-suspected cases, but several modifications must be performed on commercial EIAs to obtain good results. Moreover, samples obtained with commercial devices are more appropriate for anti-HCV detection in saliva samples.