CLINICAL ARTICLESStress Analysis of Human Tooth Root Using Various Root Canal Instruments
Section snippets
MATERIALS AND METHODS
Twelve autoclaved mesial roots of human mandibular first molars were used in this study. The crowns were removed and the roots separated with a high-speed 556 carbide bur.
The tooth roots were divided into two categories. Straight roots were defined as having the apical 4 mm aligned with no more than 5-degree divergence from the midcanal axis. Curved roots were defined as those whose apical 4 mm was at least 20 degrees divergent from the more coronal canal axis. Canals with between 5- and
RESULTS
The photographs were analyzed by digitizing the images and performing a subjective side-by-side comparison. No fringe pattern changes were observed with Lightspeed rotary files. Minimal fringe changes were observed by the observer with all rotary Tulsa and Quantec files, but never in the order of a complete fringe pattern color change. Hand filing produced minimal fringe patterning, but was noted to be concentrated adjacent to the file tip. The most pronounced fringe change of all occurred when
DISCUSSION
The ability of motor-driven noncutting tip nickel-titanium files to remain in the center of the root canal during instrumentation apparently distributes stress evenly around the circumference of the root canal preparation. Small diameter nickel-titanium files have been shown to remain centered in the canal during instrumentation, even with curved canals (6). Thus the stress placed on dentin during instrumentation should be evenly distributed.
Apparently, the force of rotary instrumentation is
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Cited by (11)
Influence of Endodontic Treatment and Retreatment on the Fatigue Failure Load, Numbers of Cycles for Failure, and Survival Rates of Human Canine Teeth
2017, Journal of EndodonticsCitation Excerpt :Another important factor with respect to the fracture strength of endodontically treated teeth is the stress generated during filling. Stress-distribution studies report stress transmission to dentin during different procedures involving strain gauges (29) or photoelastic materials (30). These studies have shown that the force to fracture a root is much higher than the force that occurs during lateral condensation.
Incidence of dentinal defects after root canal preparation: Reciprocating versus rotary instrumentation
2013, Journal of EndodonticsCitation Excerpt :The sectioning method used in the present study allowed the evaluation of the effect of root canal treatment procedures on the root dentin by direct inspection of the roots and is in agreement with a methodology described in a previous study (5). However, numerous other methods have been described such as stress distribution measurements, observations of the presence of defects in tooth sections, and resistance of the root canal–treated tooth to fracture (26–29). The latter method applies an external force until the root fractures (30).
The Effect of Root Preparation Technique and Instrumentation Length on the Development of Apical Root Cracks
2009, Journal of EndodonticsCitation Excerpt :The possibility of causing cracks after the use of what is usually considered a “safe” file size has not been previously reported in the literature. The external root stresses caused by the SF used with the balanced force technique was concentrated near the tip of the file (16). This might explain why group A showed the highest mean number of cracks (Table 1).
The ProFile system
2004, Dental Clinics of North AmericaQuasi-3D dynamic photoelastic analysis of stress distribution during preparation of simulated canals with 13 mechanical preparation systems
2023, International Endodontic Journal