Tooth displacement in shortened dental arches: a three-dimensional finite element study

Some patients may opt for a prosthetic rehabilitation without replacing all missing teeth, finishing treatment with a reduced dental arch. This choice may be due to biologic reasons or financial restrictions. It is unclear if a reduced dental arch functions as well as a complete dental arch.

The purpose of this study was to analyze whether shortened dental arches could result in tooth displacement.

Four different 3-dimensional maxillary and mandibular arches with different levels of arch length reduction were created. In all models, anatomic structures that represent the temporomandibular joint, cortical and cancellous bone, enamel, dentin, and periodontal ligament were modeled. Mechanical properties were attributed to each anatomic component, and a total occlusal load of 100 N on masseter, temporal, and medial pterygoid muscles was simulated for each model. The MSC. Patran software was used for the preprocessing and postprocessing of the biomechanical analysis of the models. One complete dental arch was used as the control.

The simulations showed that shortened dental arches presented greater tooth displacements than those found in a complete dental arch. The changes in mandibular tooth position were greater than those observed in the maxillary arches. In finite element models 1 and 2, the largest maxillary displacements were found for posterior teeth.

Decreasing numbers of occlusal units resulted in increasing amounts of displacements of the remaining teeth, which may compromise dental stability in patients with shortened dental arches.