Amir T Moinzadeh1, Lydia Farack2, Fabian Wilde3, Hagay Shemesh4, Paul Zaslansky2. 1. Department of Endodontology, Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, Amsterdam, The Netherlands. Electronic address: a.moinzadeh@acta.nl. 2. Julius Wolff Institute, Charité-Universitätsmedizin Berlin, Berlin, Germany. 3. Helmholtz-Zentrum Geesthacht (HZG), Geesthacht, Germany. 4. Department of Endodontology, Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, Amsterdam, The Netherlands.
Abstract
INTRODUCTION: This study evaluated the integrity of calcium silicate sealer-based fillings made with hygro-expandable cones (HEC) that are commercially known as CPoint or Smartpoint. METHODS: Fourteen human canines were prepared according to a standardized, conventional endodontic treatment protocol and filled with the HEC/calcium silicate sealer. Three-dimensional imaging was performed with laboratory micro-computed tomography (μCT) at its highest resolution and was compared with synchrotron phase contrast-enhanced μCT (PCE-CT) scans of the treatment extending 1-7 mm from the apex. Conventional destructive optical microscopy validated observations by comparison with virtual slices in the tomographic data. RESULTS: Conventional laboratory μCT at 10-μm resolution did not reveal the existing voids and defects within the root canal fillings. PCE-CT revealed elongated interfacial delamination localized mainly at the HEC-sealer interface forming extended through-and-through gaps along the root canal filling. CONCLUSIONS: Endodontic studies that use conventional laboratory μCT may underestimate thin defects and delamination within root canal fillings made with HEC because of limited resolution and contrast of laboratory-based broad-spectrum low intensity x-ray sources. These limitations favor use of high-brilliance, monochromatic synchrotron-based PCE-CT to reveal the important micrometer details within large (millimeter sized) samples. PCE-CT revealed the existence of a range of significant structural defects in recently placed HEC fillings, confirmed by optical microscopy after physical sectioning. Substantial delamination spanning 20%-40% of the circumferential interface as well as other structural defects were identified within root canal fillings made of HEC and calcium silicate sealer.
INTRODUCTION: This study evaluated the integrity of calcium silicate sealer-based fillings made with hygro-expandable cones (HEC) that are commercially known as CPoint or Smartpoint. METHODS: Fourteen humancanines were prepared according to a standardized, conventional endodontic treatment protocol and filled with the HEC/calcium silicate sealer. Three-dimensional imaging was performed with laboratory micro-computed tomography (μCT) at its highest resolution and was compared with synchrotron phase contrast-enhanced μCT (PCE-CT) scans of the treatment extending 1-7 mm from the apex. Conventional destructive optical microscopy validated observations by comparison with virtual slices in the tomographic data. RESULTS: Conventional laboratory μCT at 10-μm resolution did not reveal the existing voids and defects within the root canal fillings. PCE-CT revealed elongated interfacial delamination localized mainly at the HEC-sealer interface forming extended through-and-through gaps along the root canal filling. CONCLUSIONS: Endodontic studies that use conventional laboratory μCT may underestimate thin defects and delamination within root canal fillings made with HEC because of limited resolution and contrast of laboratory-based broad-spectrum low intensity x-ray sources. These limitations favor use of high-brilliance, monochromatic synchrotron-based PCE-CT to reveal the important micrometer details within large (millimeter sized) samples. PCE-CT revealed the existence of a range of significant structural defects in recently placed HEC fillings, confirmed by optical microscopy after physical sectioning. Substantial delamination spanning 20%-40% of the circumferential interface as well as other structural defects were identified within root canal fillings made of HEC and calcium silicate sealer.