AIM: To compare the effect of furcal perforations of various sizes on the biomechanical response of mandibular first molars with or without periodontal bone loss at the furcal region via three-dimensional (3D) finite element analysis (FEA). METHODOLOGY: The 3D geometric basic model was reconstructed from the micro-computed tomographic images of an extracted mandibular first molar. Five different models were constructed from this molar in group 1 as follows: intact molar model, root filled (RCF) model and three models with furcal perforations (1, 2 and 3 mm in diameter) repaired with a calcium silicate-based cement (CSC). In group 2, a lesion simulating bone resorption at the furcal region was modelled on the models in group 1. A force of 200 N was applied to simulate normal occlusal loads. Static linear FEA was performed using the Abaqus software (Abaqus 6.14; ABAQUS Inc., Providence, RI, USA). The maximum principal stresses (Pmax ) and maximum displacement magnitude were evaluated. RESULTS: The range of Pmax values of the models in group 1, from high to low, was as follows: RCF + 3 mm perforation > RCF + 2 mm perforation > RCF + 1 mm perforation > RCF > intact model, and the range of Pmax values of the models in group 2 was as follows: RCF + 3 mm perforation + furcal lesion > RCF + 2 mm perforation + furcal lesion > RCF + 1 mm perforation + furcal lesion > RCF + furcal lesion > intact model + furcal lesion. All of the models in group 2 exhibited lower Pmax values and higher maximum displacement magnitude than their counterparts without lesions in group 1. CONCLUSIONS: The size of the furcal perforation affected the accumulation and distribution of stress within the models. Mandibular molar teeth with large furcal perforations treated with a calcium silicate-based cement may be associated with an increased risk of fracture whether or not accompanied by bone resorption.
AIM: To compare the effect of furcal perforations of various sizes on the biomechanical response of mandibular first molars with or without periodontal bone loss at the furcal region via three-dimensional (3D) finite element analysis (FEA). METHODOLOGY: The 3D geometric basic model was reconstructed from the micro-computed tomographic images of an extracted mandibular first molar. Five different models were constructed from this molar in group 1 as follows: intact molar model, root filled (RCF) model and three models with furcal perforations (1, 2 and 3 mm in diameter) repaired with a calcium silicate-based cement (CSC). In group 2, a lesion simulating bone resorption at the furcal region was modelled on the models in group 1. A force of 200 N was applied to simulate normal occlusal loads. Static linear FEA was performed using the Abaqus software (Abaqus 6.14; ABAQUS Inc., Providence, RI, USA). The maximum principal stresses (Pmax ) and maximum displacement magnitude were evaluated. RESULTS: The range of Pmax values of the models in group 1, from high to low, was as follows: RCF + 3 mm perforation > RCF + 2 mm perforation > RCF + 1 mm perforation > RCF > intact model, and the range of Pmax values of the models in group 2 was as follows: RCF + 3 mm perforation + furcal lesion > RCF + 2 mm perforation + furcal lesion > RCF + 1 mm perforation + furcal lesion > RCF + furcal lesion > intact model + furcal lesion. All of the models in group 2 exhibited lower Pmax values and higher maximum displacement magnitude than their counterparts without lesions in group 1. CONCLUSIONS: The size of the furcal perforation affected the accumulation and distribution of stress within the models. Mandibular molar teeth with large furcal perforations treated with a calcium silicate-based cement may be associated with an increased risk of fracture whether or not accompanied by bone resorption.