Periodontal ligament stresses in the initiation of occlusal traumatism

Abstract

Mechanical stresses in the periodontal ligament which help initiate the lesion of occlusal trauma have been difficult to evaluate. The purpose of this study was to use a mathematical system (finite element analysis) to calculate principal periodontal ligament stresses in primary and secondary occlusal trauma. Maxillary central incisors were modeled in periodontal tissues representing four levels of bone support. Models were partitioned and subjected to three simulated functional loads. Stresses were calculated at multiple nodes in the periodontal ligament adjacent to root and bone. Results showed areas of greatest compressive stress near the alveolar crest and in the apical one‐half of the root for all loads at all bone levels. Stress curves correlated well with the histologic lesion of occlusal trauma. Centric contact loads (P3) consistently produced less ligament stress than protrusive contact (P1). Reduction of alveolar bone height had little effect on the degree of periodontal ligament stress until six millimeters (60%) of bone support had been lost. Finite element analysis provides a convenient model for the study of the mechanical component of occlusal traumatism.

Application of finite element analysis in implant dentistry: A review of the literature

“…A range of different material parameters have been recommended for use in previous FEA studies (Table I). 5,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] Several authors [34][35][36][37] have pointed out that cortical bone is neither homogeneous nor isotropic (Table II). This nonhomogenous, anisotropic, composite structure of bone possesses different values for ultimate strain and modulus of elasticity when bone is tested in compression compared with in tension.…”

Occlusal trauma and excessive occlusal forces: Narrative review, case definitions, and diagnostic considerations

“…In an in vitro study, periodontal ligament stress increased significantly after reducing 60% of bone support. 5 Because trauma from occlusion is defined and diagnosed on the basis of histologic changes in the periodontium, a definitive diagnosis of occlusal trauma is not possible without block section biopsy. Consequently, multiple clinical and radiographic indicators are used as surrogates to assist the presumptive diagnosis of occlusal trauma.…”

“…Despite the consensus on the definition of primary and secondary occlusal trauma, specific criteria to distinguish between “normal” and “reduced” periodontal support have not been identified from controlled studies. In an in vitro study, periodontal ligament stress increased significantly after reducing 60% of bone support …”

The Effect of Cavity Shape and Hybrid Layer on the Stress Distribution of Cervical Composite Restorations

“…When 200 N was loaded on the buccal tubercule and central fossa (100 N for each), more stress accu-mulation was observed on the gingival margin of the composite restoration. The gingival margin of the composite restoration was seen in yellow (38)(39)(40)(41)(42)(43)(44)(45)(46), and the occlusal margin of the composite was seen in brown (23)(24)(25)(26)(27)(28)(29)(30)(31). When the composite restoration was evaluated mesio-distally, the gingival margin was the most intense surface, and this intensity decreased the occlusal margin of the composite.…”

“…In this model, a hybrid layer was included, and the stress distribution decreased on all composite surfaces (gingival, axial, and occlusal). The gingival margin of the composite restoration was seen in dark yellow (31)(32)(33)(34)(35)(36)(37)(38), and occlusal margin of the composite restoration was seen in red (8-15 MPa) ( Figure 4). Figure 5 (Model C) shows a lower premolar tooth model with a wedge-shaped non-carious cervical lesion restored with a composite resin.…”