The influence of irrigating solutions on the accuracy of the electronic apex locator facility in the Tri Auto ZX handpiece.

AIM: To determine the influence of various irrigating solutions on the accuracy of the electronic apex locator facility in the Tri Auto ZX handpiece. METHODOLOGY: One hundred and forty teeth with single canals and mature apices, scheduled for extraction for either periodontal or prosthetic reasons in 76 patients were used. Following informed written consent local anaesthesia was administered, access cavities were prepared and pulp tissue removed. The teeth were then randomly divided into seven groups according to the irrigating solutions used. The root canal length measurements were completed using the Tri Auto ZX handpiece with automatic reverse function in the presence of one or other of the following solutions: 0.9% saline, 2.5% NaOCl, 3% H(2)O(2), 0.2% chlorhexidine, 17% EDTA, Ultracaine D-S or in the absence of an irrigating solution (control). Files were immobilized in the access cavity with composite resin. After extraction, the apical regions of the teeth were exposed and the file tips examined under a stereomicroscope. Distances between the file tips and the apical constriction were measured (mm) and analysed using a one-way anova and post hoc Tukey test. RESULTS: Mean distances from the apical constriction to the file tip were longer in the 0.9% saline group (P<0.05). There was no statistically significant difference on file tip position between the other solutions. CONCLUSIONS: Tri Auto ZX gave reliable results with all irrigating solutions apart from in the presence of 0.9% saline.

The investigation of biocompatibility and apical microleakage of tricalcium phosphate based root canal sealers.

The biocompatibility and apical microleakage of tricalcium phosphate based Sankin Apatite (SA) Type I, II, and III root canal sealers were investigated. Teflon tubes containing freshly mixed test materials were implanted in the subcutaneous tissue of mice. The observation periods were 24 h, 7, and 30 days, after which the areas of tissue reaction to the implanted materials were histopathologically analyzed. A dye-recovery, spectrophotometric method was used to evaluate apical microleakage. Results showed that the severity of tissue reaction among the tested materials decreased with time and at the end of the observation period both SA Type II and Type III were found more biocompatible than either Type I or Grossman's cement (GC). On the other hand, a fibrous tissue capsule was seen around the implants. There was no significant difference in spectrophotometrically measured leakage among teeth obturated with the test materials.

An in vitro test model for investigation of disinfection of dentinal tubules infected with Enterococcus faecalis.

The aim of the present study was to develop an in vitro test model from human teeth to comparatively examine antibacterial effectiveness of calcium hydroxide, parachlorophenol (PCP) and camphorated parachlorophenol (CPCP) against Enterococcus faecalis in infected root canals. Cylindrical dentin specimens were prepared from freshly extracted human maxillary anterior teeth. The specimens were inoculated with E. faecalis and then medicated with either CPCP, PCP or Ca(OH)2. The disinfecting efficacy of these agents was tested by collecting dentin chips from the inner ("canal") walls of the specimens and counting viable E. faecalis. The dentin chips were diluted and a classical bacterial count technique was used for recovery of E. faecalis strains of 5% sheep blood agar. The effectiveness of CPCP and PCP at one day was superior to the effectiveness of Ca(OH)2. In the three-day group, CPCP was the most effective, followed by Ca(OH)2. The experimental model used in this study may be useful for investigation of the effect of intracanal medicaments on microorganisms lodged in the root dentinal tubules.