A comparison between two fourth generation apex locators.

AIM: The aim of this study was to evaluate ex vivo the accuracy of two fourth generation apex locators and compare the measurements obtained. METHODS: Forty single and multiroots of permanent teeth (i.e., sixty-two canals) without caries or restorations were selected. After determining the real canal length using a stereomicroscope and a digital calliper, we evaluated the accuracy of two fourth generation electronic apex locators (the Bingo 1020 and the Propex) by means of an experimental study model and an endodontic simulator. The experimental model uses a digital comparator to determine the root canal length to a precision of 0.001 mm, while the endodontic simulator replicates the normal clinical condition. The difference between the real length of each canal and that obtained with the two study models was calculated. RESULTS: In both experiments, the Bingo 1020 expressed a 94.35% and the Propex expressed a mean accuracy of 90.31% in positioning the file at ± 0.5 mm. CONCLUSION: The Bingo 1020 and the Propex apex locators are equally accurate and provide reliable measurements in calculating root canal length.

Effect of unintentionally extruded mineral trioxide aggregate in treatment of root perforation with periradicular lesion: a case report.

This case report describes the effect of unintentionally extruded mineral trioxide aggregate (MTA) into periradicular lesions on the prognosis of periradicular healing in maxillary right molar with periradicular lesion. A 39-year-old male patient with a periradicular lesion from the root perforation of his maxillary right first molar was referred to our Department. A root canal retreatment was performed and the root perforation was filled with MTA. During this procedure, an unintentionally extrusion of MTA into the periradicular lesion occurred. At follow-up, the tooth was asymptomatic and at radiography a repair of the lesion was evident. No endodontic surgical treatment was necessary. In this case the healing was possible despite the extrusion of the MTA. This might be due to the biologic properties of the MTA.

Two typologies of endodontic instrument handle are here investigated for tactility modifications.

AIM: The purpose of this comparative study was to evaluate possible modifications of tactility (deep and discriminative tactile sensitivity) using manual endodontic instruments equipped with traditional handles compared with innovative silicone handle versions. METHODS: Sixteen subjects were selected and supplied with resin Endo-Training-Block simulators, latex gloves and manual endodontic instruments with diameters ranging from 10 to 40 mm. All instruments had traditional and silicon handles. The investigation of deep and discriminative tactile sensitivity was performed at 0, 15, 30, and 45 minutes of the manual instrumentation with an esthesiometer. We obtain each of our data from the median of three consecutive measurements. The results were then statistically analyzed thanks to the ANOVA test: P=0.003 for subjects, P<0.001 for time factor, and P=0.010 for sensitivity-time interaction. RESULTS: We observed a better tactility with silicone handle instruments, comparing the two kinds of handle (regardless of the finger tested) as well as singly analyzing the thumb and index finger. CONCLUSION: Despite the sample limited extension, the loss of deep cutaneous and discrimination sensitivity seems to be reduced using silicone handles, most likely favoring an improvement of the working performance.

The corrosive effects of sodium hypochlorite on nickel-titanium endodontic instruments: assessment by digital scanning microscope.

AIM: Prolonged contact (several hours) of nickel-titanium (NiTi) endodontic instruments with sodium hypochlorite has a considerable corrosive effect which reduces the instruments' resistance to fractures. The aim of this study was to verify whether short-term contact (several minutes, as is the case in clinical practice) produces the same effects. METHODS: Using a digital scanning microscope, the blade surfaces of three groups of ProTaper instruments were examined, particularly of the #1 Shaping File. The blade's file (but not their handles) were soaked in sodium hypochlorite heated to 50 degrees C for three different times compatible with times in clinical practice, rather for 2, 5 and 10 minutes; the files were then compared with a control group. RESULTS: The micro-photographs did not reveal any appreciable signs of corrosion on the file blades. CONCLUSIONS: It is evident, therefore, that using sodium hypochlorite as an irrigating solution in root canals, where it comes into contact with NiTi rotary endodontic instruments, does not alter the surface structure of the files through corrosion. Thus it is possible to conclude that, considering the length of time used in clinical practice, sodium hypochlorite does not cause any increase of risk of fracture to Ni-Ti rotary instruments.