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BERLIN, Germany/AMSTERDAM, Netherlands: Scientists have examined several dozen dental roots at BESSY II, both before and after treatment, and found that mechanical procedures during treatment do not contribute to microfractures. BESSY II is a synchrotron radiation source and produces ultra-bright photon beams.
One possible complication of root canal treatment is root fracture, which usually leads to tooth loss. The cause of such fractures is not fully understood, but some researchers have suggested that stress on the roots arising from mechanical instrumentation or filling procedures during treatment may contribute to the appearance of fractures or cracks.
Two researchers have now tested this hypothesis using the BAM imaging beamline at BESSY II. Dr Paul Zaslansky from the Berlin-Brandenburg Centre for Regenerative Therapies at Charité—Universitätsmedizin Berlin and Dr Hagay Shemesh from the Academisch Centrum Tandheelkunde Amsterdam (academic centre for dentistry in Amsterdam) in the Netherlands examined several dozen dental roots at BESSY II, both before and after treatment.
“No systematic investigation has yet rigorously shown whether instrumentation of root canals can lead to fracture in treated teeth. Modern imaging methods at synchrotron facilities can help us learn more about the extent of the problem and possible solutions,” Zaslansky believes. In order to investigate this, he applied for measurement time at BESSY II and transported extracted teeth from the dental clinic at Charité to the facility. Zaslansky examined the roots for possible cracks before, during, and after root canal treatment performed in the synchrotron by Shemesh.
Tomographic datasets were acquired using the high-resolution CT set-up of the KMC2 BAMline operated at BESSY II by the German Federal Institute for Materials Research and Testing (BAM). BESSY II provides laser-like coherent X-rays that can be used to produce contrast between areas of similar density to be visualised by use of interference effects, revealing significant details in the images (using phase contrast-enhanced imaging).
“This allowed us to investigate the boundary between the filling and the dental root in detail and at high resolution. Two important problems are of concern: first, voids in the filling that may be colonised by biofilms, leading to bacterial infections later on, and second, fine cracks that may develop into fractures of the root,” said Zaslansky.
His first impression was that failed root canal treatment is probably not due to the treatment procedures or the tools used. Microcracking detected after instrumentation was always visible beforehand, suggesting that the treatment did not cause the damage. “We treated many of the teeth with somewhat more aggressive instruments and expected considerably more damage, but we didn’t observe this,” Zaslansky said. The damage may arise simply due to daily use, he suspects: “Powerful forces develop when chewing, and if the filling does not evenly distribute these forces, this can also lead to the tooth breaking.”
The relevance of the results is not limited to dentists alone, but extends to manufacturers of dental instruments and filling materials. “Our findings give us some initial clues as to what goes on during and after treatment. We will have to expand the research,” Zaslansky summed up. Systematic, comprehensive investigation could show where critical cracks tend to appear during root canal treatment, and which procedures are more likely to lead to successful outcomes. Patients could then have greater confidence that the repaired tooth would remain functional for many years.
