Research On Invisible Correction Design System For Direct 3D Printing

The development of additive manufacturing(3D printing)technology has brought tremendous changes in the manufacturing,medical and other industries.In the field of orthodontics,the combination of computer graphics technology and additive manufacturing technology has produced a bracketless invisible correction technology.This technology has gained more and more favored orthodontic patients.However,the current bracketless invisible appliance is manufactured by 3D printing to obtain a dental model as a master mold,and then using a medical resin film on the master mold for thermoforming.The invisible appliance obtained by this method cannot obtain the ideal diaphragm thickness,so that the corrective force cannot be accurately controlled and affects the correction effect.This indirect manufacturing method inactivates the accuracy of 3D printing and does not allow precise correction.With the rapid development of medical materials for additive manufacturing technology,direct 3D printing invisible appliances are gradually becoming possible,and research on its design system is one of the key technologies.In this paper,aiming at the problems of indirect generation process of invisible appliance,such as long process route,low manufacturing precision and inability to accurately design the appliance,a stealth correction design system scheme for direct 3D printing was proposed and a functional model of the software system was constructed.Aiming at the key problem of dental jaw segmentation,a morphological segmentation algorithm is proposed.The algorithm combines the morphological algorithm and the Dijkstra algorithm.Morphological algorithm screens the feature region of the model,and the Dijkstra algorithm is used to obtain the segmentation curve of the appliance in the dental model.The obtained appliance generation area is complete,and the segmentation efficiency of the dental model is improved.The object-oriented programming method was used to design the system.The C# language and the 3D graphics processing library Open GL were used to develop the dental model file preprocessing module,the dental model file interactive display module,the virtual tooth module,and the Invisible appliance virtual generation module.Finally,through an example,the invisible appliance designed for 3D printing was designed by using the developed software.The direct 3D printing of the invisible appliance was completed by SLA method,and the system verification was completed.The proposed appliance segmentation algorithm is suitable for the virtual generation of invisible appliance,which can improve the segmentation efficiency of the dental model and ensure the integrity of the segmentation model.Through the research on the direct 3D printing invisible correction design system,the bracketless invisibility is realized.The direct rapid manufacturing of the appliance improves the process precision of the appliance and shortens the technical cycle,which lays a foundation for the later mechanical analysis of the appliance and more precise correction research.