Brief communication: Comparing loading scenarios in lower first molar supporting bone structure using 3D finite element analysis

Abstract

Finite element analysis (FEA) is a widespread technique to evaluate the stress/strain distributions in teeth or dental supporting tissues. However, in most studies occlusal forces are usually simplified using a single vector (i.e., point load) either parallel to the long tooth axis or oblique to this axis. In this pilot study we show how lower first molar occlusal information can be used to investigate the stress distribution with 3D FEA in the supporting bone structure. The LM(1) and the LP(2) -LM(1) of a dried modern human skull were scanned by μCT in maximum intercuspation contact. A kinematic analysis of the surface contacts between LM(1) and LP(2) -LM(1) during the power stroke was carried out in the occlusal fingerprint analyzer (OFA) software to visualize contact areas during maximum intercuspation contact. This information was used for setting the occlusal molar loading to evaluate the stress distribution in the supporting bone structure using FEA. The output was compared to that obtained when a point force parallel to the long axis of the tooth was loaded in the occlusal basin. For the point load case, our results indicate that the buccal and lingual cortical plates do not experience notable stresses. However, when the occlusal contact areas are considered, the disto-lingual superior third of the mandible experiences high tensile stresses, while the medio-lingual cortical bone is subjected to high compressive stresses. Developing a more realistic loading scenario leads to better models to understand the relationship between masticatory function and mandibular shape and structures. Am J Phys Anthropol, 2012. © 2011 Wiley Periodicals, Inc.

Reliability Estimation for Single-unit Ceramic Crown Restorations

“…While a good representation of shape can be gained, accuracy may be sacrificed with the 3-D model because of these limitations (Romeed et al, 2006). The 2-D model used in this study is a good representation of actual tooth shape, because both loading and geometry were similar throughout the sections in the distal aspect (Benazzi et al, 2012), and, more importantly, it leads to a more conservative estimation. Potential improvement with a 3-D model is not expected to be sufficient to explain differences between clinical data and predictions, because a 3-D model may require more approximations in the stage of probability calculations taking place after finite element analysis.…”

The Evolutionary Paradox of Tooth Wear: Simply Destruction or Inevitable Adaptation?

“…With regard to the loading direction, for maximum intercuspation contact we can assume that a compressive force acts between complementary wear facet pairs, which could ultimately be represented as perpendicular loads to these facets [30], [55]–[56] (Figure 8). …”

“…Boundary constraints were applied to the medial and distal cut surfaces of the mandible section following indications provided by Benazzi et al [56]: the medial nodes were restrained only in x-axis translation (linguo-buccally), while the distal nodes were restrained both in the y- and z-axes (supero-inferiorly and medio-distally, respectively). The load (uniform pressure) was distributed proportionally according to the occlusal contact areas detected in the OFA software (Figure 8) and was such that the magnitude of the resultant vector was equal to 100 N. A large range of occlusal loads have been proposed in the literature.…”

“…The load (uniform pressure) was distributed proportionally according to the occlusal contact areas detected in the OFA software (Figure 8) and was such that the magnitude of the resultant vector was equal to 100 N. A large range of occlusal loads have been proposed in the literature. Nonetheless, since we are interested in the patterns of stress distribution rather than predicting realistic loads that cause fractures of the tooth, the magnitude of the occlusal load is not a crucial factor, since at each material point of the model the stress is linearly proportional to the magnitude of force applied [56], [64].…”

“…The stress state patterns were qualitatively and quantitatively compared according to the first maximum principal stresses criterion for brittle materials [29], [30], [56], [65], [66], wherein the stresses inform about tensile behaviour in specific sites of the volumetric meshes.…”