Effect of biomimetic material on stress distribution in mandibular molars restored with inlays: a three-dimensional finite element analysis

Abstract

Background Although biomimetic material has become increasingly popular in dental cosmetology nowadays, it remains unclear how it would affect the restored teeth during chewing. It is necessary to study the influence of biomimetic material on stress distribution in the restored teeth. Methods Eight three-dimensional finite element (FE) models were constructed and divided into two groups. Group 1 included the FE model of intact molar, and the FE models of inlay-restored molars fabricated from IPS e.max CAD, Lava Ultimate and biomimetic materials individually. Enamel was considered a homogeneous material. Group 2 included the FE models of intact molar and molars restored with inlays using IPS e.max CAD, Lava Ultimate and biomimetic materials individually, considering enamel as an inhomogeneous material. Results In Group 1, compared with that in the intact molar, the maximum tensile stress (MTS) in the occlusal grooves decreased in the inlay-restored molars fabricated from IPS e.max CAD and was concentrated on the cavity floor at the buccal side in the inner dentin around inlay. When Lava Ultimate was selected, MTS decreased in the occlusal grooves and on the cavity floor but increased in the lateral walls. In the restored molar using biomimetic material, the MTS on the cavity floor was distributed more evenly than that in the molar using IPS e.max CAD, and no obvious changes were noted in the lateral walls. The same changes were observed in Group 2. No differences in the stress distribution pattern were noted among the FE models in Groups 1 and 2. Conclusions Molars restored with inlays fabricated from biomimetic material exhibit a more uniform stress distribution in the dentin around restoration. The consideration of enamel as a homogeneous tissue is acceptable for analyzing the maximum principal stress distribution in the inlay-restored molar.

Influence of the cervical margin relocation on stress distribution -

“…A restoration must resist natural forces that occur in the mouth [14][15][16] . A 45-degree angle to the long axis of the tooth was chosen to match the lateral the force (eccentric force) applied on the teeth during mastication 12,[17][18][19][20] while an 11-degree angle to the long axis of the tooth was chosen to match the applied perpendicular force (centric force) on the teeth (90 degrees) during mastication 10 .…”

“…After the models were meshed, two different oblique forces each of 100N [14][15][16] were applied as two load cases, one at (11º) 10 and the other at (45º) 10,14-18 from the vertical long axis of the tooth. Each load was equally divided on 15 points representing; outer, inner surface cusp tips of labial cusp, inner surface of lingual cusp, central and mesial triangular fossa distal and mesial marginal ridge 18 as presented in (Figure 1). Thus, totally six runs were performed on the two models as following:-Two runs on the model1 (one at 11º and other at 45º) from vertical axis and four runs on CMR materials of model II (one run at 11º and other at 45º on Dyract Flow) & (one run at 11º and other at 45º on Riva light cure glass ionomer) from the vertical axis 10,13 .…”

Influence of Cavity Geometry on the Fracture Strength of Dental Restorations: Finite Element Study

“…Moreover, Tortopidis et al [50] measured a maximum biting force of 580 N in healthy people's posterior areas. Besides the tooth loading level, the restorative procedure has been identified as another parameter influencing the stress and strain levels of restored teeth [19,20,35,38,41,43,51]. All researchers reported that teeth with onlay restorations appear more resistant to fracture than those with inlay restorations.…”

“…Boundary conditions were applied in the five faces of the box that supported the teeth, assuming that the faces were connected to the remaining maxillary bone and, therefore, the three nodal displacements of all nodes placed over those faces were restrained. The load was applied on a 28.3 mm 2 circle as a homogenously distributed pressure corresponding to an oblique load of 500 N at 30 • to the tooth axis (Figure 2c) [37,38]. The loads were applied gradually to avoid dynamic effects and convergence problems.…”

Comportamento biomimético dos pinos de fibra de vidro: relato de caso

“…Esses materiais tem a capacidade de mimetizar as características originais da estrutura dentária de forma mais eficiente, tais como: pinos de resina reforçados por fibra de vidro, resinas compostas e sistemas cerâmicos, incluindo as porcelanas 2,3 .…”