Stress distribution in the temporomandibular joint after mandibular protraction: A three-dimensional finite element study

Abstract

Objective: To evaluate the stress patterns in temporomandibular joint (TMJ) during mandibular protraction at different horizontal advancements with constant vertical height in a construction bite using a three-dimensional finite element method. Materials and Methods: A three-dimensional computer-aided model was developed from the magnetic resonance imaging (MRI) of a growing boy (age 12 years) using MIMICS software (version 7.0, Materialise, Leuven, Belgium). Stresses with constant vertical opening of 5 mm changing the sagittal advancements from 0 mm to 5 mm and 7.5 mm were recorded. Differences in magnitude and pattern of stresses were compared. Results: The tensile stresses in the posterosuperior aspect of the condylar head and on the posterior aspect of the glenoid fossa migrated posteriorly with increased bite advancements. The location of tensile stresses changed in the condylar head and fossa on mandibular protraction of 5 mm to 7 mm. Conclusion: This study indicates that larger horizontal advancements of construction bites may not be favorable for tissues of TMJ. Clinical application necessitates study on an animal model.

Effects of the advanced mandibular spring on mandibular retrognathia treatment: a three-dimensional finite element study

“…4 ). It corresponded to Shrivastava’s [ 39 ] FEA results that compressive stress in the anterior aspect reduced after advancement. Studies have shown that continuous compression on the condylar cartilage decreased the proliferation of chondrocytes and the amount of extracellular matrix [ 45 ], and induced cartilage thinning [ 46 ].…”

“…Studies have shown that when condylar chondrocytes experienced pressure unloading as the posterior part of the condyle deviated from the glenoid fossa, they responded biologically to unloading, enhancing their differentiation and maturation, eventually resulting in increased ossification [ 8 , 9 ] and substantial new bone formation in the posterior aspect of condyle [ 42 ]. Existing FEA attributed condylar growth to the increased tensile stress on the condyle in the mandibular advanced position [ 39 , 43 ], while the results of the present study showed that the initial pressure in the superior and posterior aspects of the condyle was released to near zero by AMS (Fig. 4 ).…”

“…Complete components were also included in our modeling process. The geometric model was constructed using images of CBCT and spiral CT. CBCT has been widely used for modelling [ 15 , 24 , 39 ] for its high spatial resolution. With the data from CBCT, we obtained a fine model of dentition and jaw which distinguished roots from the alveolar bone.…”

“…5 ). Shrivastava et al found that stress in the middle aspect of the disc reduced in mandibular advancement, but that in the posterior aspect increased [ 39 ]. We didn’t find stress change in the posterior aspect but identified similar reducing stress in the intermediate zone.…”

Evaluation of biomechanical effects of interocclusal surfaces on the mandible

“…1 This aspect is very important from the clinical perspective since it enables to establish the effects of the modification of such parameters during orthognathic surgery and gnathologic or orthodontic treatments. [3][4][5][6] Among mathematical models, the most renowed one is the finite element method (FEM), which originates from the principles of electronic. After many enhancements, FEM is employed nowadays in the biomechanical analysis of the stomatognathic system contributing to the current knowledge despite the difficulties encountered in the evaluation of the mechanical properties of the biological tissues.…”