Comparison of working length control consistency between hand K-files and Mtwo NiTi rotary system

Background

The purpose of this study was to investigate the consistency of working length control between hand instrumentation in comparison to engine driven Mtwo nickel-titanium rotary files.

Material and Methods

Forty extracted maxillary molars were selected and divided onto two parallel groups. The working lengths of the mesiobuccal root canals were estimated. The teeth were fixed in a phantom head. The root canal preparation was carried out group 1 (n=20) with hand K-files, (VDW, Munich, Germany) and group 2 (n=20) with Mtwo instruments (VDW, Munich, Germany). Vestibulo-oral and mesio-distal directional x-ray images were taken before the preparation with #10 K-file, inserted into the mesiobuccal root canal to the working length, and after preparation with #25, #30 and #40 files. Working lenght changes were detected with measurements between the radiological apex and the instrument tips.

Results

In the Mtwo group a difference in the working competency (p<0.05) could be noticed only in the vestibulo-oral direction from #10 to #40 file. The hand instrument group showed a significant difference in working length competency for each larger file size (p<0.05) (ANOVA). Regression analysis in the hand instrumentation group indicated a working length decrease with a mean of 0,2 mm after each consecutive file size (p<0.01).

Conclusions

The outcome of our trial indicated a high consistency in working length control for root canal preparation under simulated clinical condition using Mtwo rotary files. Mtwo NiTi rotary file did therefore proved to be more accurate in comparison to the conventional hand instrumentation.

Key words:Working length, Mtwo, nickel-titanium, hand preparation, engine driven preparation.

Chemomechanical preparation by hand instrumentation and by Mtwo engine-driven rotary files, an ex vivo study

Objective: To compare the disinfecting efficacy of the sodium hypochlorite irrigation by root canal preparation with stainless steel hand files, taper 0.02 and nickel-titanium Mtwo files with taper 0.04-0.06. Study Design: 40 extracted human teeth were sterilized, and then inoculated with Enterococcus faecalis (ATCC 29212). After 6 day incubation time the root canals were prepared by hand with K-files (n=20) and by engine-driven Mtwo files (VDW, Munich, Germany) (n=20). Irrigation was carried out with 2.5% NaOCl in both cases. Samples were taken and determined in colony forming units (CFU) from the root canals before and after the preparation with instruments #25 and #35. Results: Significant reduction in bacterial count was determined after filing at both groups. The number of bacteria kept on decreasing with the extension of apical preparation diameter. There was no significant difference between the preparation sizes in the bacterial counts after hand or engine-driven instrumentation at the same apical size. Statistical analysis was carried out with Mann-Whitney test, paired t-test and independent sample t-test. Conclusions: Significant reduction in CFU was achieved after the root canal preparation completed with 2.5% NaOCl irrigation, both with stainless steel hand or nickel-titanium rotary files. The root canal remained slightly infected after chemo mechanical preparation in both groups.

Key words:Chemomechanical preparation, root canal disinfection, nickel-titanium, conicity, greater taper, apical size.

Peri-ictal vegetative symptoms in temporal lobe epilepsy

We investigated peri-ictal vegetative symptoms (PIVS) in 141 patients with adult temporal lobe epilepsy (TLE) and assessed frequency, gender effect, and lateralizing value of peri-ictal autonomic signs. We recorded abdominal auras in 62%, goosebumps in 3%, hypersalivation in 12%, spitting in 1%, cold shivering in 3%, urinary urge in 3%, water drinking in 7%, postictal nose wiping (PNW) in 44%, and postictal coughing in 16%. At least one vegetative sign appeared in 86% of the patients. The presence of PIVS did not have a significant lateralizing value. PNW occurred in 52% of women and in 33% of men, whereas any PIVS was present in 93% of women and 77% of men. In summary, contradictory to previous studies, the presence of PIVS has no lateralizing value, which may be linked to a low frequency of occurrence of PIVS. PIVS, especially PNW, occurred more frequently in women, supporting the gender differences in epilepsy.

Patients' ability to react before complex partial seizures

OBJECTIVE

The purpose of the study described here was to investigate the pathophysiology of patients' ability to react during the conscious (aura) phase of complex partial seizures (CPS) originating from the temporal lobe.

METHODS

We reviewed video recordings of CPS experienced by 130 adult patients who had undergone epilepsy surgery for intractable medial temporal lobe epilepsy. All patients were instructed to push the alarm button when they felt an aura. We defined the preictal reactivity as the ability to push the alarm button before the complex partial (unconscious) phase of seizures.

RESULTS

Seventy-seven patients (59%) pushed the alarm button before seizures. Patients with preictal reactivity were significantly younger, more often had lateralized EEG seizure patterns, and had a better postoperative outcome. Patients who did not push the alarm button had secondarily generalized seizures more often.

CONCLUSIONS

Ability to react before CPS is associated with a circumscribed region involved at seizure onset and spread, and with a seizure-free postoperative outcome.

AX.25 amateur packet radio as a possible emergency network

In modern society more and more medical applications need a reliable data transfer. In emergency situations, such transfer may not be available because parts of the communications infrastructure may be affected. An alternative way could be the use of the amateur radio packet network, which offers almost global coverage. We analyzed its use as an emergency data transfer support, including transport of real-time medical data.

Social and personal factors in marijuana use and intentions to use drugs among inner city minority youth

Limited information is available about the etiology of illicit drug use among minority youth. This study examined predictors of marijuana use and intentions to use marijuana, cocaine/crack, and other drugs for African-American and Hispanic seventh graders (N = 757). Self-reports of marijuana use and intentions to use drugs were collected along with data concerning background, social environmental, and individual characteristics hypothesized to be related to drug use. Results indicated that social influences, including adults, friends, and the most admired person's marijuana use, predicted marijuana use. Individual characteristics, such as a lack of knowledge about the prevalence and negative social consequences of marijuana use, positive attitudes toward marijuana use, and inadequate social, communication, and refusal skills increased suspectability to marijuana use. Lack of self-efficacy was related to intentions to use cocaine and other drugs. Implications of these findings are discussed with respect to the development of effective prevention programs.