Validation of retention capsules for polyacetal overdentures made from 3D printing

Abstract

The standard therapy for total edentulism is still the use of total dentures. With dental loss, there is a constant and intense bone reabsorption of the mandibular rim, which in many cases leads to partial success of the use of total dentures, since it generates a lack of retention and stability of the lower prostheses. Meanwhile, overdentures-type implant-supported prostheses solve, in most cases, the problems associated with the use of conventional prosthetic devices. The o-ring overdenture retention system presents great advantages, mainly for geriatric patients, who present the highest prevalence of edentulism. However, the main disadvantage of this type of engagement is the gradual loss of retention of the capsule sealing rings, which leads to periodic exchanges thereof. Concomitantly to this, the application of 3D printers to materialize products has a direct impact on the way in which we think and produce manufactures today, since the additive technology has been increasing exponentially every day in its use and application to the various areas of knowledge . In this way, the objective of the study will be to validate a model of polyacetal retention capsule (POM) printed on a 3D printer comparing its mechanical properties with those obtained from manual manufacturing in relation to retention, surface roughness, compression and surface hardness, besides evaluating the deformation of them. For this, a retention capsule model will be made in three-dimensional modeling software (Rhinoceros® 3D), as well as the test specimen models for the compression tests, surface roughness and surface hardness. 20 capsules (n = 10) made of Polyacetal will be printed on the 3D printer (Stella® 2) and 20 capsules (n = 10) will be machined in the USP Precision Workshop, inserted and removed from mini-implants Ø 2, 0 mm by 10 mm in length with coupled o-ring (MDL; Intra-Lock System, São Paulo, SP) by means of a fatigue resistance machine and performance compared to those obtained from manual manufacture. The capsules will be evaluated in Steriomicroscope to verify possible deformations. In addition, 30 specimens (n = 10) will be printed and 30 specimens (n = 10) will be machined for the tests of surface hardness, roughness and compressive strength, respectively. After the proposed analyzes, the data obtained will be submitted to adequate statistical treatment to evaluate the results.