In silico study of cuspid' periodontal ligament damage under parafunctional and traumatic conditions of whole-mouth occlusions. A patient-specific evaluation

• Published in: Computer methods and programs in biomedicine 2020-02, Vol.184, p.105107-105107, Article 105107
• Main Authors: Ortún-Terrazas, Javier, Cegoñino, José, Pérez del Palomar, Amaya
• Format: Article
• Language: English
• Subjects: Computer Simulation; Cuspid - diagnostic imaging; Cuspid - pathology; Cuspid - physiopathology; Dental Occlusion; Extracellular Matrix - pathology; Finite Element Analysis; Finite element method; Humans; Micro-computed tomography; Multiscale analysis; Occlusal trauma; Periodontal Ligament - diagnostic imaging; Periodontal Ligament - pathology; Periodontal Ligament - physiopathology; Periodontal ligament damage; Porous fibrous behaviour; Stress, Mechanical; Wounds and Injuries - pathology; X-Ray Microtomography
• ISSN: 0169-2607; 1872-7565
• DOI: 10.1016/j.cmpb.2019.105107

•Multiscale simulation related the 3D loading conditions with the damage in the periodontal ligament microstructure.•Early contact of the cuspid tooth guides the mandible and absorbs lateral occlusal forces of around 5 to 35 N for physiological and traumatic loadings, respectively.•The periodontal ligament exhibits a high time-dependent behaviour, characterised by a persisting stress state between loading cycles.•The high lateral and compressive loads in grinding conditions may cause damage in the extracellular matrix of the periodontal ligament.•The traumatic forces could deteriorate the collagen network of the ligament and therefore they may cause the overpressure (>4.7 kPa) of its interstitial fluid. Although traumatic loading has been associated with periodontal ligament (PDL) damage and therefore with several oral disorders, the damage phenomena and the traumatic loads involved are still unclear. The complex composition and extremely thin size of the PDL make experimentation difficult, requiring computational studies that consider the macroscopic loading conditions, the microscopic composition and fine detailed geometry of the tissue. In this study, a new methodology to analyse the damage phenomena in the collagen network and the extracellular matrix of the PDL caused by parafunctional and traumatic occlusal forces was proposed. The entire human mandible and a portion thereof containing a full cuspid tooth were separately modelled using finite element analysis based on computed tomography and micro-computed tomography images, respectively. The first model was experimentally validated by occlusion analysis and subjected to the muscle loads produced during hard and soft chewing, traumatic cuspid occlusion, grinding, clenching, and simultaneous grinding and clenching. The occlusal forces computed by the first model were subsequently applied to the single tooth model to evaluate damage to the collagen network and the extracellular matrix of the PDL. Early occlusal contact on the left cuspid tooth guided the mandible to the more occluded side (16.5% greater in the right side) and absorbed most of the lateral load. The intrusive occlusal loads on the posterior teeth were 0.77–13.3% greater than those on the cuspid. According to our findings, damage to the collagen network and the extracellular matrix of the PDL could occur in traumatic and grinding conditions, mainly due to fibre overstretching (>60%) and interstitial fluid overpressure (>4.7 kPa), respecti