Assessment of Transpalatal Arch Activations: A Comprehensive Review of In Vitro Studies

(Pages: 49-53)

Rosangela Cannavale1, Maddalena Vitale1, Fabrizia d’Apuzzo1, Abdolreza Jamilian2, Maria Lepore3 and Vincenzo Grassia1

1Multidisciplinary Department of Medical-Surgical and Dental Specialties, University of Campania “Luigi Vanvitelli”, Via L. De Crecchio 6, 80138 Naples, Italy; 2Department of Orthodontics, Cranio Maxillofacial Research Center, Tehran Dental Branch, Islamic Azad University, Tehran, Iran; 3Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, Via L. De Crecchio 7, 80138 Naples, Italy


The biomechanical understanding of the removable transpalatal arch (TPA) is complex because it represents a two-bracket system that is constrained at both ends. This system is defined as statically indeterminate because some of the unknown forces and moments cannot be calculated from the force and moment equilibrium formula. No previous studies reviewed this aspect. The aim of this comprehensive review was to assess different activation of transpalatal arch in vitro studies.
A review of the literature was carried out using the following electronic databases: MEDLINE via PubMed, EMBASE via Ovid, LILAC, Scopus and Web of Science (ISI).
A total of 205 papers were selected if they reported analysis of transpalatal arch activation. A final number of 7 studies met the inclusion criteria and were included for analysis. The types of activation with the transpalatal arch evaluated in the studies were: torque, derotation and expansion.
The torque and expansion activations were shown in two studies, whereas the derotation activation was described in four studies in the literature. The results indicated that the transpalatal arch activations cannot be accurately evaluated, because of several consistent biases showed in the methodology and results reported in the included studies, as well as the different type of stainless steel and the wideness, height, length of the transpalatal arch. Thus, further research with more homogeneous inclusion criteria and type of activations is needed in next studies.

Keywords: Transpalatal arch, stainless steel, in vitro studies, activation, torque, derotation, expansion.