IADR Abstract Archives
Failures of Endodontically Treated Maxillary Central and Second Premolars Under Hydrostatic Pressure
Objectives: Maxillary second premolars have a higher incidence of vertical root fracture (VRF) post-endodontic treatment compared to maxillary incisors. In previous reports experimentally VRF was induced by loading the roots using various spreaders; the consequence of which is local stress concentration. The aim of this study was to determine the internal hydrostatic pressure that will create failure in entire roots of maxillary second premolars (MSP) compared to maxillary central incisors (MCI) by a pressurization technique.
Methods: The crown-down technique with final apical filing to No. 50 was used to endodontically treat 16 MSP and 25 MCI. Circular stainless steel plates with two small tubes extending from both sides connected the tooth to a pressure system. One tube was bonded to the access cavity preparation to the level of the CEJ; the other was connected to a piston. The apical and coronal ends of the root canal were sealed using flowable composite resin and Penloc acrylic resin, respectively. A pressure transducer directly measured the pressure that developed in the system. The piston was pressed in a constant speed that elevated the internal hydrostatic pressure until failure. Pressure vs. Time and Force was continuously recorded.
Results: Pressure at failure for MCI was significantly higher than for MSP (255±45 bar and 191±33 bar, respectively; p=0.001). Failure was expressed either as separation of fragments= fracture (44%) or crack (56%). The mean pressure of all sample at crack (232±44 bar) and fracture (216±54 bar) were not statistically different (p=0.62).Cracks extended from apex to CEJ (61%), from apex to mid-root (26%) or from mid-root to CEJ (13%).Cracks were either bilateral (52%) or unilateral (48%) involving mainly the buccal (83%) or lingual (63%) surfaces.
Conclusions: Premolars are more prone to VRF compared to incisors. The pattern of failure mainly originated from the apex.
Methods: The crown-down technique with final apical filing to No. 50 was used to endodontically treat 16 MSP and 25 MCI. Circular stainless steel plates with two small tubes extending from both sides connected the tooth to a pressure system. One tube was bonded to the access cavity preparation to the level of the CEJ; the other was connected to a piston. The apical and coronal ends of the root canal were sealed using flowable composite resin and Penloc acrylic resin, respectively. A pressure transducer directly measured the pressure that developed in the system. The piston was pressed in a constant speed that elevated the internal hydrostatic pressure until failure. Pressure vs. Time and Force was continuously recorded.
Results: Pressure at failure for MCI was significantly higher than for MSP (255±45 bar and 191±33 bar, respectively; p=0.001). Failure was expressed either as separation of fragments= fracture (44%) or crack (56%). The mean pressure of all sample at crack (232±44 bar) and fracture (216±54 bar) were not statistically different (p=0.62).Cracks extended from apex to CEJ (61%), from apex to mid-root (26%) or from mid-root to CEJ (13%).Cracks were either bilateral (52%) or unilateral (48%) involving mainly the buccal (83%) or lingual (63%) surfaces.
Conclusions: Premolars are more prone to VRF compared to incisors. The pattern of failure mainly originated from the apex.