Strength Testing of Materials Used for 3D Printing of Dental Splints

Abstract

The purpose of the study was to serve as a preliminary study about material testing of three different materials, which are used to 3D print dental splints with DPL technique. A dental laboratory has the resins for 3D printing the dental splints instead of milling them from a disc, but the mechanical properties of the 3D printed parts from these resins have to be found out before 3D printing for real use can be started. By switching the production of dental splints from milling technique to 3D printing, significant reduction in material waste and material costs would be possible, which would bring also other advantages for the dental laboratory, such as increased competitiveness. The reduced waste material would also make the production more sustainable, which was also one of the reasons for this thesis.

The thesis was done by discussing first with the personnel of the dental laboratory about their needs and specifications for the material testing. The main method of doing the thesis was to find information about the topic and apply it so that the thesis can be used as a guide for the physical material testing, which would be done later, after the testing methods have been accepted by the dental laboratory and the material testing laboratories. Also, a thesis about a similar topic has been done in Savonia in 2017 by Jussi Hiltunen and the thesis worked also as one of the main information sources for this thesis. Other studies about the 3D printing settings and their effect on the mechanical properties were found and they were put to a simpler form, such as tables, to be available in this thesis when the material testing is done.

A lot of information was found of the effect of 3D printing settings on the mechanical properties of the 3D printed test samples. The studied settings included printing orientation, layer thickness, exposure time and lifting speed, in addition to the effect of surface quality. The effect of these factors was concluded in this thesis based on the found information. The testing procedures of the standards were also simplified in forms of charts. The flexural strength testing and elongation at break testing methods would still need further re-search concerning the testing method and the type of test sample. Other possible topics for further research could be the effect of lifting speed since limited information was found. Also, the amount of reduced material waste could be measured by measuring the weight of the disc from which the dental splints are milled from. Finding suitable devices for IZOD impact testing and wear resistance testing would also be possibilities for further research.