Experimental Study on the Mechanical Behavior of Orthodontic Arches Exposed to the Environment in the Oral Cavity.

Alexandru Zalana ,Ciprian Ion Rizescu,Maria Dămășaru,Edgar Moraru,Simina Chelărescu ,Stanca Cuc

doi:10.3390/children9010107

Abstract

Background. The arches used in orthodontic therapy are subject to increasing physical and chemical stresses. Purpose of the study: This in vitro experimental study aims to highlight and compare the main mechanical properties of orthodontic arches. Materials and Methods: We used 40 springs, 2 materials, 20 of Ni-Cr and 20 of Co-Cr, of different diameters, 0.7 mm 0.8 mm and 1.2 mm, subjected to the environment of artificial saliva and artificial saliva with cola for one month and two months, respectively. Five springs of each material were tested at different times: T0, before application in the oral cavity, then at time T1, T2, T3, T4. Three lengths of the lever arm were considered for bending forces acting on the springs (dental wires). These lengths were 15, 10 and 5 mm. The wires were tested under the action of bending forces on a Hans Schmidt HV 500N stand, obtaining the characteristics of the wires: deformation-force-time. Results: Graphical determinations show that the degree of deformation of the wires is influenced by the applied force, diameter and obviously by the immersion time, respectively by the type of solution in which the springs were immersed. Conclusions: The final degree of bending is higher for Co-Cr arcs than for Ni-Cr at all three dimensions.

Highlights

Orthodontic mobile appliances are made of an acrylic base, active and anchoring elements made of orthodontic wires
Comparing the deformations of the springs over time, we found a linear increase from T0, 1 month after immersion in saliva, respectively from 1.2 mm to 2.10
Exceptions are these springs at an interval of 1 month of immersion in artificial saliva, when we found a slight increase in the degree of deformation from 0.87 mm, as it was initially, to 0.97 mm

Summary

Introduction

Orthodontic mobile appliances are made of an acrylic base, active and anchoring elements made of orthodontic wires. Three types of lengths of the lever arm with which the spring was deformed were simulated, 15(l3), 10(l2) and 5(l1) mm, which represent via analogy the distance from the base of the device where the spring is inserted to the contact with the tooth These wires were tested under the action of bending forces on a Hans Schmidt HV 500 N stand, equipped with an IMADA force transducer, the data received being received FbtFhiyigeguauwrreceior33em..sXX:pYYduetttaafebborllreetmhffrraaoottmmiogHnHenV-Vfeo5r5r0a0c0t0ees-sedteti-tmua-upegp..r. aphical interpretation obtaining the characteristics of pressAinngIfMorAceDFiaAgcucfrooerr3dc.eiXnYtgratatnobsledthfureocmetrraHivsVeol5p0lee0nrsagettte-hud;pdo. The orthodontic wires were considered recessed springs at one end, actuated with a force at three different lengths These wires were tested under the action of bending forces on a Hans Schmidt HV 500 N stand, equipped with an IMADA force transducer, the data received being received by a computer that generated a graphical interpretation obtaining the characteristics of the wires: deformation-force-time. F[1i4g]u. rFeig6usrheo6wsshothwes gthraepghraopfhlionfelainr eraergregssreiosnsiofonrfothreth0e.70.m7 mmdid6aimoaf me17tetrer NNiCiCr wr wirier.e

Results

Months in Artificial Saliva

Conclusions