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Publications (5)14.77 Total impact

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    ABSTRACT: This study evaluated the influence of flexibility and reciprocating movement on the fatigue life of endodontic instruments subjected to static and dynamic tests. The rotary nickel-titanium instruments used in this study were Reciproc and Mtwo. The instruments were initially subjected to a cantilever-bending test and then to static and dynamic fatigue tests. Reciproc instruments were operated in reciprocating movement, whereas Mtwo instruments were worked in continuous rotation. The means of bending resistance (maximum load in grams) of the instruments were 274.9 for Reciproc and 429 for Mtwo. The mean times (in seconds) to fracture of the instruments subjected to static and dynamic tests were 214.5 (static) and 286.3 (dynamic) for Reciproc and 38.9 (static) and 99 (dynamic) for Mtwo. The Student's t test revealed significant differences in all tests (P < .05). The results of the present study showed longer fatigue life for instruments with higher flexibility, driven by reciprocating movement, and in the dynamic testing model. These findings reinforce the assumption that use of reciprocating movement is a means to prolong the fatigue life of rotary nickel-titanium endodontic instruments during instrumentation of curved canals.
    Journal of endodontics 05/2013; 39(5):693-6. · 2.95 Impact Factor
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    ABSTRACT: This study compared the mechanical properties of endodontic instruments made of conventional nickel-titanium (NiTi) wire (K(3) and Revo-S SU), M-Wire (ProFile Vortex), or NiTi alloy in R-phase (K(3)XF). The test instruments were subjected to mechanical tests to evaluate resistance to bending (flexibility), cyclic fatigue, and torsional load in clockwise rotation. Data were statistically evaluated by the analysis of variance test and the Student-Newman-Keuls test for multiple comparisons. In the bending resistance test, flexibility decreased in the following order: K(3)XF > Revo-S SU > ProFile Vortex > K(3). The ranking in the fatigue resistance test was the following: K(3)XF > K(3) > ProFile Vortex > Revo-S SU. In the torsional assay, the angular deflection at failure decreased in the following order: K(3)XF > Revo-S SU > K(3) > ProFile Vortex. For the maximum torque values, the ranking was K(3) > K(3)XF > ProFile Vortex > Revo-S SU. The results showed that the K(3)XF instrument, which is made of NiTi alloy in R-phase, had the overall best performance in terms of flexibility, angular deflection at failure, and cyclic fatigue resistance. In addition to the alloy from which the instrument is manufactured, the design and dimensions are important determinants of the mechanical performance of endodontic instruments.
    Journal of endodontics 04/2013; 39(4):516-20. · 2.95 Impact Factor
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    ABSTRACT: This study compared the mechanical properties of 3 pathfinding endodontic instruments. The test instruments were subjected to mechanical tests to evaluate resistance to bending (flexibility), buckling, cyclic fatigue, and torsional load in clockwise rotation. Data were statistically evaluated by analysis of variance and the Student-Newman-Keuls test for multiple comparisons. In the buckling resistance test, the highest values were observed for C-Pilot files (VDW, Munich, Germany) and the lowest for Scout RaCe (FKG Dentaire, La Chaux-de-Fonds, Switzerland) instruments. In the bending resistance test, the lowest flexibility was observed for the C-Pilot instrument, and no significant difference was observed between Scout RaCe and PathFile (Maillefer/Dentsply, Ballaigues, Switzerland) instruments. The ranking in the fatigue resistance test was the following: PathFile > Scout RaCe > C-Pilot, with statistically significant differences observed in the number of cycles to fracture between all the instruments. In the torsional assay, the angular deflection to fracture decreased in the following order: Scout RaCe > PathFile > C-Pilot. As for the maximum torque values, the ranking was as follows: C-Pilot > PathFile > Scout RaCe. Findings revealed that the stainless-steel C-Pilot instrument showed increased resistance to buckling but decreased flexibility and cyclic fatigue resistance when compared with nickel-titanium pathfinding instruments. PathFile instruments showed the highest resistance to cyclic fatigue, and Scout RaCe files exhibited the highest angular deflection to fracture. The different mechanical behavior of the instruments indicates that the combined use of stainless steel hand instruments and rotary nickel-titanium instruments during the exploration of narrow curved canals may be necessary to exploit the best performance of each pathfinding instrument.
    Journal of endodontics 10/2012; 38(10):1417-21. · 2.95 Impact Factor
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    ABSTRACT: This study compared the buckling resistance of the following endodontic pathfinding instruments: C-Pilot file (VDW, Munich, Germany), C+ file (Maillefer/Dentsply, Ballaigues, Switzerland), and PathFile (Maillefer/Dentsply). The test instruments were subjected to a devised buckling resistance test, which consisted of the application of an increasing load in the axial direction of the instrument by using a universal testing machine. The maximum load required to generate a lateral elastic displacement of 1 mm was recorded for each instrument. The results indicated that the buckling resistance decreased in the following order: C+ file > C-Pilot file > PathFile. The difference was statistically significant (P < .05). The stainless steel instruments (C+ and C-Pilot) were more resistant to buckling than the nickel-titanium instrument (PathFile). Considering that buckling resistance may influence the performance of instruments during the negotiation of constricted canals, the C+ files showed significantly better results than the other instruments tested.
    Journal of endodontics 03/2012; 38(3):402-4. · 2.95 Impact Factor
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    ABSTRACT: This article describes a case of recurrent post-treatment apical periodontitis and late failure after endodontic retreatment performed in a single visit. The patient presented with a tooth exhibiting inadequate endodontic treatment and a large periradicular lesion that extended laterally to the root. Retreatment was performed in a single visit and involved chemomechanical preparation using 5.25% NaOCl as the irrigant and root canal obturation by Schilder's vertical compaction technique. A large lateral canal was radiographically revealed after obturation. After 2 years, the lesion was no longer radiographically discernible, a condition that was confirmed 9 years after retreatment procedures. Nonetheless, after 12 years, radiographs revealed recurrent disease. Apical surgery was performed, and the root apex, including the area of the large lateral canal, was resected with care to maintain the lesion attached to it. The biopsy specimen was subjected to histopathologic and histobacteriologic analyses. Longitudinal sections of the apical root specimen revealed a heavy dentinal tubule infection surrounding the area of the lateral canal. Bacteria were not found in any other area of the specimen. No other possible reason for the inflammatory periradicular lesion, such as root fracture, coronal leakage, or foreign-body reaction, was evident. A persistent intraradicular infection caused by bacteria located within dentinal tubules is the most reasonable explanation for resurgence of the apical periodontitis lesion. This case report stresses the importance of attaining proper disinfection of the root canal system for a predictable long-term outcome of the treatment.
    Journal of endodontics 02/2012; 38(2):250-4. · 2.95 Impact Factor