Effects of post-curing conditions on mechanical properties of 3D printed clear dental aligners

Purpose 3D printing techniques have been widely used for manufacturing complex parts for various dental applications. For achieving suitable mechanical strength, post-cure processing is necessary, where the relative time duration and temperature specification also needs to be defined. The purpose of this study/paper is to assess the effects of post curing conditions and mechanical properties of 3D printed clear dental aligners Design/methodology/approach Dental long-term clear resin material has been used for 3D printing of dental aligners using a Formlabs 3D printer for direct usage on patients. Post-curing conditions have been varied, all of which have been subjected to mechanical compression loading of 1,000 N to evaluate the curing effects on the mechanical strength of the aligners. Findings The experimental studies provide significant insight into both temperatures and time durations that could provide sufficient compressive mechanical strength to the 3D printed clear dental aligners. It was observed that uncured aligners deformed plastically with large deformations under the loading conditions, whereas aligners cured between 400 degrees C-800 degrees C for 15-20 min deformed elastically before fragmenting into pieces after safely sustaining higher compressive loads between 495 N and 666 N. The compressive modulus ratio for cured aligners ranged between 4.46 and 5.90 as compared to uncured aligners. For shorter cure time durations and lower temperature conditions, an appropriate elevated compressive strength was also achieved. Originality/value Based on initial assessments by dental surgeons, suitable customised clear aligners can be designed, printed and cured to the desired levels based on patient's requirements. This could result in time, energy and unit production cost savings, which ultimately would help to alleviate the financial burden placed on both the health service and their patients.