Finite element and in vitro study on biomechanical behavior of endodontically treated premolars restored with direct or indirect composite restorations.
Level 5 - mechanism / opinion, no new human data
In vitro mechanical testing and computational finite element analysis (bench research)
PubMed 35879388 · doi:10.1038/s41598-022-16480-0
What was done
A 3D finite element analysis (FEA) model of an endodontically treated premolar was created to evaluate three composite restoration techniques: direct restoration (DR), endocrown (EC), and post, core, and crown (C). Restorations were modeled with two supporting tissue conditions (periodontal ligament/alveolar bone vs. polymethyl methacrylate) under an 850 N two-point axial occlusal load to assess von Mises stresses and strains. In vitro static fracture resistance testing was performed on corresponding restored teeth (n = 5 per group) using a 6.0 mm ball indenter under vertical loading.
What was found
Peak stresses and strains across all FEA models localized to occlusal and vestibular cervical surfaces, aligning with in vitro fracture propagation sites. Conventional crowns (C) had the lowest stress in dentin, while endocrowns (EC) generated lower stresses and strains in crown cement. Periodontal ligament/bone models showed larger high-stress root areas than PMMA models. In vitro fracture resistance showed no statistically significant differences between groups (DR: 747.7 ± 164.0 N; EC: 867.3 ± 108.1 N; C: 866.9 ± 126.3 N; p = 0.307).
Why it matters
The findings suggest that more conservative restorative options, including direct composite restorations and endocrowns, may provide biomechanical performance comparable to traditional post-and-core crowns in severely compromised premolars.
Limits
The study is limited by its bench-top in vitro and simulated computational design. The in vitro sample size was small (n = 5 per group), and testing relied entirely on static vertical loading, omitting dynamic fatigue, lateral masticatory forces, thermocycling, and intraoral biological factors.
Cited by
- context Compressive loads on composite fillings cause stress and shock waves that produce microfractures in the surrounding tooth structure.