Comparison of apical sealing and periapical extrusion of the ThermaFil obturation technique with and without MTA as an apical barrier: An in vitro study.

Aim: The aim of the study was to compare the conventional ThermaFil obturation technique and ThermaFil obturation with mineral trioxide aggregate (MTA) as an apical barrier, with regard to apical sealing and extrusion. Materials and Methods: Twenty extracted human canines were instrumented using a crown-down technique and divided into two groups. The experimental group was obturated using ThermaFil obturation with MTA as an apical barrier and the control group was obturated using the conventional ThermaFil obturation technique. AH Plus sealer was used in both the groups. Apical extrusion was recorded. Teeth of both the groups were coated with nail polish, except for the apical 3 mm. After 24 h, they were suspended in black India ink for 48 h. Canines were decalcified, rendered transparent, and linear dye penetration was measured under ×40 stereomicroscope. Results: There was a significant extrusion noticed in conventional ThermaFil obturation technique. Frequency of extrusion of sealer and/or gutta-percha was supposed to be evaluated using χ² test, but since the values of the samples of ThermaFil plus MTA group were zero, statistical analysis could not be conducted, whereas linear dye leakage was calculated with Mann-Whitney U test because the distribution was abnormal. Conclusion: Although ThermaFil plus MTA group showed microleakage, extrusion of sealer and the core material was prevented in comparison with conventional ThermaFil obturation technique. It is advantageous to use MTA as an apical plug as there is no fear of apical extrusion and the root canal system can then be packed three dimensionally against this barrier using any thermoplasticized gutta-percha obturation technique.

Rotary Mtwo system versus manual K-file instruments: Efficacy in preparing primary and permanent molar root canals.

Aim: To compare the cleaning ability and preparation time of rotary instruments (Mtwo) and conventional manual instruments (K-file) in preparing primary and permanent molar root canals. Materials and Methods: Access cavities were prepared in 70 primary and 70 permanent teeth and India ink was injected into 120 canals of selected molars. The teeth were randomly divided into two main subgroups (n=20) and three control groups (n=10). In each of these main subgroups, either the manual instrument (K-file) or the rotary system (Mtwo) was used to prepare root canals. After cleaning the canals and clearing the teeth, dye removal was evaluated with the help of a stereomicroscope. In addition, the time needed for root canal preparation was recorded by a chronometer. Statistical Analysis: Statistical analyses were done using the Kruskal-Wallis, Mann-Whitney and t tests. Results: With regard to the cleaning ability of root canals, there were no significant differences between the K-file and Mtwo rotary system in primary and permanent teeth in the apical, middle or coronal third of the canals. Moreover, there were no significant differences between primary and permanent teeth prepared with K-files and rotary instruments. In all the groups, shorter times were recorded with the rotary technique. The working time was shorter in primary than in permanent teeth. Conclusion: The Mtwo rotary system showed acceptable cleaning ability in both primary and permanent teeth, and achieved results similar to those of K-files in less time.

Evaluation of conventional & serological methods for rapid diagnosis of cryptococcosis.

BACKGROUND & OBJECTIVE: Cryptococcosis is a chronic infective condition affecting the central nervous system. Unless diagnosed early and specific treatment instituted it can be fatal. There is an urgent need for a rapid and specific diagnostic tool for better management of the patients. Conventional methods such as culture and India ink are specific but cumbersome and time consuming. Serological methods of detection are rapid but have problems of false positivity and cross-reactivity with other micro-organisms. We carried out this study to compare and evaluate the conventional methods with serological methods of detection of cryptococcal meningitis. METHODS: A comparative evaluation of conventional methods (India ink and culture) with LAT (latex agglutination test) and EIA (enzyme immunoassay) was done in 127 CSF samples using culture and EIA as reference separately. RESULTS: India ink was positive for Cryptococcus in 72.4 per cent of the samples; 56 per cent were culture positive; LAT positive were 85 per cent and 79.5 per cent were positive by EIA. When culture was positive, all other tests were in agreement to it. However, when culture was negative there was significant difference between the pair of discordance of various diagnostic tests. Culture was 83.46 per cent in agreement to India ink, 76.3 per cent to EIA and 70.8 per cent to LAT. EIA was 92.9 per cent in agreement to India ink and LAT; 6.3 per cent showed false positive by LAT. INTERPRETATION & CONCLUSION: EIA is valuable in establishing diagnosis when culture is negative for cryptococcosis. EIA is more specific and has potential advantages over LAT as it gives clear discrimination of positive from negative results. Thus, EIA may be used as a simple, rapid, and reliable serological test for early detection of cryptococcal antigen in clinical samples like CSF in routine laboratories.