23 - Mechanical Strength Evaluation of a Printed Dental Space Maintainer

Abstract

Due to the latest progress of 3D scanning and printing technology in the medical field, attempts have been made to apply this technology also in preventive orthodontics in order to obtain an aesthetic dental space maintainer. The aim of this study is to observe the mechanical load distribution on a SLA band and loop space maintainer in order to develop a high-precision aesthetic dental space maintainer using computer-aided design (CAD) / computer-aided manufacturing (CAM) and 3D printing by resin-based additive technique. On account of increasing aesthetic requirements, an initiative was made to replace the classic band and loop space maintainer with a metal-free appliance, using an innovative technique for creating the esthetic design of the space maintainer. Four band and loop space maintainers were achieved through stereolithography (SLA). After scanning the dental cast, a 3D software Exocad was used to establish the design of the dental space maintainer. They were manufactured using two different 3D printers, two with Formlabs form2 using C&B Micro Filld Hybrid (MFH) resin and two with Creality using NextDent SG resin. After printing, all samples were placed in an isopropyl alcohol bath to clean them of residues and resin excess, then placed in the UV oven for drying. Shortly afterwards processing they were subjected to the mechanical strength test by compression using the Zwick/ Roell Z005 device. For the fulfillment of the mechanical resistance tests, the dental cast made by the classic plaster technique was used as support. Following mechanical tests, it was observed that these devices yielded to the action of a vertical force between 16-31 N. There were no significant differences between the two materials, but the highest resistance was observed in the C&B Micro resin Filld Hybrid (MFH) using Formlabs form2 printer which is consistent with the minimum masticatory forces developed in mixed dentition 26.21-41.5 N for males and 8.05-12.61 for females. Given the importance of dental aesthetics nowadays, 3D printing offers the possibility to manufacture an aesthetic dental space maintainer device with a better adaptation to the clinical situation. The mechanical properties being closely related to the object design, it is important to ensure a sufficient thickness of the device to prevent fractures under the masticatory forces.