Effects of heat treatment temperature and time on the fitness accuracy, retentive force, and permanent deformation of selective laser melting Ti-6Al-4V clasps

Abstract

The selective laser melting (SLM) technology of Ti-6Al-4V (TC4) demonstrates significant advantages in fabricating clasps for removable partial dentures, whereas subsequent heat treatment plays a crucial role in performance optimization. This study systematically investigated the effects of heat treatment temperature and time on the fitness accuracy, retentive force, and permanent deformation of SLM TC4 clasps. TC4 clasp specimens were manufactured using SLM technology and subjected to heat treatment under different temperatures (700, 750, 800, and 850℃) and times (0.5, 1.0, and 1.5 h). The fitness accuracy, retentive force, and permanent deformation after 10,000 insertion/removal cycles were measured for each group and statistically analyzed. The results revealed that the 700℃/0.5 h group showed significantly reduced fitness accuracy. After cyclic testing, the retentive force of all groups decreased by 4.06%–12.18%, with heat treatment temperature significantly affecting both initial and final retentive forces. The time of heat treatment demonstrated no substantial influence. The permanent deformation of the clasps (31.15–38.05 μm) remained unaffected by variations in either heat treatment temperature or time. Based on overall performance, the 700℃/0.5 h heat treatment condition is not recommended. Instead, selecting shorter time protocols such as 0.5 h within the 750℃–850℃ range can help enhance production efficiency while maintaining performance standards.

Keywords

Heat treatment / Ti-6Al-4V clasp / Selective laser melting / Fitness accuracy / Retentive force / Permanent deformation

Funding

This study was supported by the Technology Innovation and Application Development Program of Chongqing Science and Technology Bureau (cstc2020jscx-sbqwX0006) and the 2023 medical education research project of the medical education branch of the Chinese Medical Association and the National Center for the development of medical education (No.2023A50).

Conflict of Interest

Peng Wang and Lu Liu are employees of Chongqing Jingmei Medical Technology Co., Ltd.; however, they were not involved in any activities that could constitute a conflict of interest in relation to this study. We declare that we have no personal relationships with other people or organizations that can inappropriately influence our work. There are also no potential conflicts of interest in terms of employment, consultancies, ownership, honoraria, paid expert testimony, patent applications/registrations, and grants or other funding.

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