AccScience Publishing / MSAM / Volume 5 / Issue 2 / DOI: 10.36922/MSAM025490118
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ORIGINAL RESEARCH ARTICLE

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

Lu-Xiang Yu1,2† ,  Na Yu1,2† ,  Jing-Jing Fan1,2 ,  Peng Wang3 ,  Lu Liu3 ,  Fa-Bing Tan1,2,4*
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1 Department of Prosthodontics, College of Stomatology, Chongqing Medical University, Chongqing, China
2 Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
3 Chongqing Jingmei Medical Technology Co., Ltd., Chongqing, China
4 Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
†These authors contributed equally to this work.
MSAM 2026, 5(2), 025490118 https://doi.org/10.36922/MSAM025490118
Received: 7 December 2025 | Accepted: 20 January 2026 | Published online: 12 March 2026
© 2026 by the Author(s).. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )
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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.

Graphical abstract
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.
References
  1. Ohkubo C, Hanatani S, Hosoi T. Present status of titanium removable dentures - a review of the literature. J Oral Rehabil. 2008;35(9):706-714. doi: 10.1111/j.1365-2842.2007.01821.x
  2. Ohkubo C, Sato Y, Nishiyama Y, Suzuki Y. Titanium removable denture based on a one-metal rehabilitation concept. Dent Mater J. 2017;36(5):517-523. doi: 10.4012/dmj.2017-137
  3. Da Silva L, Martinez A, Rilo B, Santana U. Titanium for removable denture bases. J Oral Rehabil. 2000;27(2):131-135. doi: 10.1046/j.1365-2842.2000.00506.x
  4. Miyazaki T, Hotta Y, Kunii J, Kuriyama S, Tamaki Y. A review of dental CAD/CAM: current status and future perspectives from 20 years of experience. Dent Mater J. 2009;28(1):44-56. doi: 10.4012/dmj.28.44
  5. Qiu J, Liu W, Wu D, Qiao F, Sui L. Fit accuracy in the rest region of RPDs fabricated by digital technologies and conventional lost-wax casting: A systematic review and meta-analysis. BMC Oral Health. 2023 23(1):667. doi: 10.1186/s12903-023-03348-6
  6. Watanabe I, Watanabe E, Yoshida K, Okabe T. Effect of surface contamination on adhesive bonding of cast pure titanium and Ti-6Al-4V alloy. J Prosthet Dent. 1999;81(3):270-276. doi: 10.1016/s0022-3913(99)70268-4
  7. Baltag L, Watanabe K, Kusakari H, Miyakawa O. Internal porosity of cast titanium removable partial dentures: Influence of sprue direction on porosity in circumferential clasps of a clinical framework design. J Prosthet Dent. 2002;88(2):151-158. doi: 10.1067/mpr.2002.127400
  8. Rodrigues RCS, Faria ACL, Orsi IA, De Mattos MDC, Macedo AP, Ribeiro RF. Comparative study of two commercially pure titanium casting methods. J Appl Oral Sci. 2010;18(5):487-492. doi: 10.1590/s1678-77572010000500010
  9. Takahashi K, Torii M, Nakata T, Kawamura N, Shimpo H, Ohkubo C. Fitness accuracy and retentive forces of additive manufactured titanium clasp. J Prosthodont Res. 2020;64(4):468-477. doi: 10.1016/j.jpor.2020.01.001
  10. Gao BW, Zhao HJ, Peng LQ, Sun ZX. A review of research progress in selective laser melting (SLM). Micromachines (Basel). 2023;14(1):57. doi: 10.3390/mi14010057
  11. Kessler A, Hickel R, Reymus M. 3D printing in dentistry-state of the art. Oper Dent. 2020;45(1):30-40. doi: 10.2341/18-229-l
  12. Lindner M, Hoeges S, Meiners W, et al. Manufacturing of individual biodegradable bone substitute implants using selective laser melting technique. J Biomed Mater Res Part A. 2011;97A(4):466-471. doi: 10.1002/jbm.a.33058
  13. Polozov I, Nefyodova V, Zolotarev A, Popovich A. Microstructural evolution and mechanical properties of laser-powder bed fusion-fabricated Ti-10Ta-2Nb-2Zr alloy as a potential orthopedic implant material. Mater Sci Addit Manuf. 2025;4(3):025220044. doi: 10.36922/msam025220044
  14. Zhenhuan W, Yu D, Junsi L, et al. Physiochemical and biological evaluation of SLM-manufactured Ti-10Ta-2Nb- 2Zr alloy for biomedical implant applications. Biomed Mater. 2020;15(4):045017. doi: 10.1088/1748-605X/ab7ff4
  15. Sabban R, Bahl S, Chatterjee K, Suwas S. Globularization using heat treatment in additively manufactured Ti-6Al-4V for high strength and toughness. Acta Mater. 2019;162:239-254. doi: 10.1016/j.actamat.2018.09.064
  16. Liu JW, Zhang K, Gao X, et al. Effects of the morphology of grain boundary α-phase on the anisotropic deformation behaviors of additive manufactured Ti-6Al-4V. Mater Des. 2022;223:111150. doi: 10.1016/j.matdes.2022.111150
  17. Wang CS, Lei Y, Li CL. Achieving an excellent strength and ductility balance in additive manufactured Ti-6Al-4V alloy through multi-step high-to-low-temperature heat treatment. Materials (Basel). 2023;16(21):6947. doi: 10.3390/ma16216947
  18. Gushchina M, Turichin G, Klimova-Korsmik O, Babkin K, Maggeramova L. Features of heat treatment the Ti-6Al-4V GTD blades manufactured by DLD additive technology. Materials (Basel). 2021;14(15):4159. doi: 10.3390/ma14154159
  19. Zou ZY, Simonelli M, Katrib J, Dimitrakis G, Hague R. Refinement of the grain structure of additive manufactured titanium alloys via epitaxial recrystallization enabled by rapid heat treatment. Scr Mater. 2020;180:66-70. doi: 10.1016/j.scriptamat.2020.01.027
  20. Zhang S, Zhang YQ, Zou ZY, Shi YS, Zang Y. The microstructure and tensile properties of additively manufactured Ti-6Al-2Zr-1Mo-1V with a trimodal microstructure obtained by multiple annealing heat treatment. Mater Sci Eng A Struct Mater Prop Microstruct Process. 2022;831:142241. doi: 10.1016/j.msea.2021.142241
  21. Chen J, Fabijanic D, Brandt M, Zhao Y, Ren SB, Xu W. Dynamic α globularization in laser powder bed fusion additively manufactured Ti-6Al-4V. Acta Mater. 2023;255:119076. doi: 10.1016/j.actamat.2023.119076
  22. Wang D, Wang H, Chen XJ, et al. Densification, tailored microstructure, and mechanical properties of selective laser melted Ti-6Al-4V alloy via annealing heat treatment. Micromachines (Basel). 2022;13(2):331. doi: 10.3390/mi13020331
  23. Ahn B. Microstructural tailoring and enhancement in compressive properties of additive manufactured Ti-6Al-4V alloy through heat treatment. Materials (Basel). 2021;14(19):5524. doi: 10.3390/ma14195524
  24. Fathy SM, Emera RMK, Abdallah RM. Surface microhardness, flexural strength, and clasp retention and deformation of acetal vs poly-ether-ether ketone after combined thermal cycling and pH aging. J Contemp Dent Pract. 2021;22(2):140-145. doi: 10.5005/jp-journals-10024-2937
  25. Zhang MM, Gan N, Qian HX, Jiao T. Retentive force and fitness accuracy of cobalt-chrome alloy clasps for removable partial denture fabricated with SLM technique. J Prosthodont Res. 2022;66(3):459-465. doi: 10.2186/jpr.jpr_d_21_00017
  26. Mahmoud AAA, Wakabayashi N, Takahashi H. Prediction of permanent deformation in cast clasps for denture prostheses using a validated nonlinear finite element model. Dent Mater. 2007;23(3):317-324. doi: 10.1016/j.dental.2005.10.012
  27. Benso B, Kovalik AC, Jorge JH, Campanha NH. Failures in the rehabilitation treatment with removable partial dentures. Acta Odontol Scand. 2013;71(6):1351-1355. doi: 10.3109/00016357.2013.777780
  28. Brandt S, Winter A, Lauer HC, Romanos G. Retrospective clinical study of 842 clasp-retained removable partial dentures with a metal framework: Survival, maintenance needs, and biologic findings. Quintessence Int. 2024;55(9):704-711. doi: 10.3290/j.qi.b5566187
  29. El-Tamimi KM, Bayoumi DA, Alshenaiber R, Aljulayfi I, Ahmed MMZ, El-Sayed ME. Deformation and retentive forces variations of the additively manufactured cobalt-chromium and titanium alloys dental clasps. Saudi Dent J. 2024;36(6):947-953. doi: 10.1016/j.sdentj.2024.04.001
  30. Behr M, Zeman F, Passauer T, et al. Clinical performance of cast clasp-retained removable partial dentures: A retrospective study. Int J Prosthodont. 2012;25(2):138-144. doi: 10.1016/j.joen.2011.12.003
  31. Zheng J, Aarts JM, Ma SY, Waddell JN, Choi JJE. Different Undercut depths influence on fatigue behavior and retentive force of removable partial denture clasp materials: A systematic review. J Prosthodont. 2023;32(2):108-115. doi: 10.1111/jopr.13519
  32. Tan FB, Song JL, Wang C, Fan YB, Dai HW. Titanium clasp fabricated by selective laser melting, CNC milling, and conventional casting: A comparative in vitro study. J Prosthodont Res. 2019;63(1):58-65. doi: 10.1016/j.jpor.2018.08.002
  33. Yan X, Lin H, Wu Y, Bai W. Effect of two heat treatments on mechanical properties of selective-laser-melted Co-Cr metal-ceramic alloys for application in thin removable partial dentures. J Prosthet Dent. 2018;119(6): 1028.e1-1028.e6. doi: 10.1016/j.prosdent.2018.04.002
  34. Xie WQ, Zheng MH, Wang JQ, Li XY. The effect of build orientation on the microstructure and properties of selective laser melting Ti-6Al-4V for removable partial denture clasps. J Prosthet Dent. 2020;123(1):163-172. doi: 10.1016/j.prosdent.2018.12.007
  35. Hussein MO, Hussein LA. Trueness of 3D printed partial denture frameworks: Build orientations and support structure density parameters. J Adv Prosthodont. 2022;14(3):150-161. doi: 10.4047/jap.2022.14.3.150
  36. Nakata T, Shimpo H, Ohkubo C. Clasp fabrication using one-process molding by repeated laser sintering and high-speed milling. J Prosthodont Res. 2017;61(3):276-282. doi: 10.1016/j.jpor.2016.10.002
  37. Shimpo H. Effect of arm design and chemical polishing on retentive force of cast titanium alloy clasps. J Prosthodont. 2010;17(4):300-307. doi: 10.1111/j.1532-849X.2007.00289.x
  38. Tokue A, Hayakawa T, Ohkubo C. Fatigue resistance and retentive force of cast clasps treated by shot peening. J Prosthodont Res. 2013;57(3):186-194. doi: 10.1016/j.jpor.2013.01.006
  39. Zhu YH, Zhang B, Liu YH, Qin F, Li HF, Zheng YF. [Fracture analyses of casting framework removable partial dentures]. Beijing Da Xue Xue Bao Yi Xue Ban. 2012;44(1):80-83. doi: 10.3969/j.issn.1671-167x.2012.01.017
  40. Ghouse S, Oosterbeek RN, Mehmood AT, Vecchiato F, Dye D, Jeffers JRT. Vacuum heat treatments of titanium porous structures. Addit Manuf. 2021;47:102262. doi: 10.1016/j.addma.2021.102262
  41. Wang QP, Kong J, Liu XK, et al. The effect of a novel low-temperature vacuum heat treatment on the microstructure and properties of Ti-6Al-4V alloys manufactured by selective laser melting. Vacuum. 2021;193:110554. doi: 10.1016/j.vacuum.2021.110554
  42. Singla AK, Banerjee M, Sharma A, et al. Selective laser melting of Ti6Al4V alloy: Process parameters, defects and post-treatments. J Manuf Processes. 2021;64:161-187. doi: 10.1016/j.jmapro.2021.01.009
  43. Zha S, Zhang H, Yang J, Zhang Z, Qi X, Zu Q. Fatigue threshold and microstructure characteristic of TC4 titanium alloy processed by laser shock. Metals. 2025;15(4):453. doi: 10.3390/met15040453
  44. Rodrigues RCS, Ribeiro RF, De Mattos MDC, Bezzon OL. Comparative study of circumferential clasp retention force for titanium and cobalt-chromium removable partial dentures. J Prosthet Dent. 2002;88(3):290-296. doi: 10.1067/mpr.2002.128128
  45. Chastand V, Quaegebeur P, Maia W, Charkaluk E. Comparative study of fatigue properties of Ti-6Al-4V specimens built by electron beam melting (EBM) and selective laser melting (SLM). Mater Charact. 2018;143:76-81. doi: 10.1016/j.matchar.2018.03.028
  46. Parry L, Ashcroft IA, Wildman RD. Understanding the effect of laser scan strategy on residual stress in selective laser melting through thermo-mechanical simulation. Addit Manuf. 2016;12:1-15. doi: 10.1016/j.addma.2016.05.014
  47. Li C, Fu CH, Guo YB, Fang FZ. Fast prediction and validation of part distortion in selective laser melting. Proced Manuf. 2015;1:355-365. doi: 10.1016/j.promfg.2015.09.042
  48. Yang JJ, Yu HC, Yin J, Gao M, Wang ZM, Zeng XY. Formation and control of martensite in Ti-6Al-4V alloy produced by selective laser melting. Mater Des. 2016;108:308-318. doi: 10.1016/j.matdes.2016.06.117
  49. Kok Y, Tan XP, Wang P, et al. Anisotropy and heterogeneity of microstructure and mechanical properties in metal additive manufacturing: A critical review. Mater Des. 2017;139(FEB.):565-586. doi: 10.1016/j.matdes.2017.11.021
  50. Cao S, Chu RK, Zhou XG, et al. Role of martensite decomposition in tensile properties of selective laser melted Ti-6Al-4V. J Alloy Compd. 2018;744:357-363. doi: 10.1016/j.jallcom.2018.02.111
  51. Kruth JP, Deckers J, Yasa E, Wauthlé R. Assessing and comparing influencing factors of residual stresses in selective laser melting using a novel analysis method. Proc Inst Mech Eng Part B J Eng Manuf. 2012;226(B6):980-991. doi: 10.1177/0954405412437085
  52. Han SJ, Bang GB, Kim WR, et al. Effect on microstructural and mechanical properties of selective laser melted pure Ti parts using stress relief heat-treatment process. J Mater Res Technol. 2023;27:200-208. doi: 10.1016/j.jmrt.2023.09.288
  53. Yu WL, Zhu WL, Yin A, et al. Investigation of thermal stability of residual stresses and microstructure of dual shot peened TC17 titanium alloy. J Alloy Compd. 2025;1010:178075. doi: 10.1016/j.jallcom.2024.178075
  54. Li H, Jia D, Yang Z, et al. Effect of heat treatment on microstructure evolution and mechanical properties of selective laser melted Ti-6Al-4V and TiB/Ti-6Al-4V composite: A comparative study. Mater Sci Eng A. 2021;801:140415. doi: 10.1016/j.msea.2020.140415
  55. Chen SG, Ma JL, Gao HJ, Wang YS, Chen X. Research on residual stresses and microstructures of selective laser melted Ti6Al4V treated by thermal vibration stress relief. Micromachines. 2023;14(2):354. doi: 10.3390/mi14020354
  56. Skvortsova SV, Ivanov AE, Spektor VS, Shalin AV, Smirnov PA. Effect of heat treatment on the residual stresses, mechanical properties, and texture formation in VT6 alloy samples fabricated by selective laser melting. In: Russian Metallurgy (Metally). Germany: Springer 2024;(2):2024. doi: 10.1134/S0036029524700794
  57. Tanaka A, Miyake N, Hotta H, Takemoto S, Yoshinari M, Yamashita S. Change in the retentive force of Akers clasp for zirconia crown by repetitive insertion and removal test. J Prosthodont Res. 2019;63(4):447-452. doi: 10.1016/j.jpor.2019.02.005
  58. Snyder HA, Duncanson MG Jr. The effect of clasp form on permanent deformation. Int J Prosthodont. 1992;5(4):345-350.
  59. Bergman B, Hugoson A, Olsson CO. A 25 year longitudinal study of patients treated with removable partial dentures. J Oral Rehabil. 1995;22(8):595-599. doi: 10.1111/j.1365-2842.1995.tb01055.x
  60. Torii M, Nakata T, Takahashi K, Kawamura N, Shimpo H, Ohkubo C. Fitness and retentive force of cobalt-chromium alloy clasps fabricated with repeated laser sintering and milling. J Prosthodont Res. 2018;62(3):342-346. doi: 10.1016/j.jpor.2018.01.001
  61. Rues S, Tasaka A, Fleckenstein I, et al. Fit and retention of cobalt-chromium removable partial denture frameworks fabricated with selective laser melting. J Funct Biomater. 2023;14(7):416. doi: 10.3390/jfb14080416
  62. Ahmed N, Abbasi MS, Haider S, et al. Fit accuracy of removable partial denture frameworks fabricated with CAD/ CAM, rapid prototyping, and conventional techniques: A systematic review. Biomed Res Int. 2021;2021:3194433. doi: 10.1155/2021/3194433
  63. Kola MZ, Raghav D, Kumar P, Alqahtani F, Murayshed MS, Bhagat TV. In vitro assessment of clasps of cobalt-chromium and nickel-titanium alloys in removable prosthesis. J Contemp Dent Pract. 2016;17(3):253-257. doi: 10.5005/jp-journals-10024-1836
  64. Ganor YI, Tiferet E, Vogel SC, et al. Tailoring microstructure and mechanical properties of additively-manufactured Ti6Al4V using post processing. Materials (Basel). 2021;14(3):658. doi: 10.3390/ma14030658
  65. Xu MR, Lin Y, Lin ZX, Cheng H. Elastic and fatigue properties of additively manufactured and milled Ti-6Al-4V removable partial denture clasps. J Prosthet Dent. 2025;133(1):230e1-230e8. doi: 10.1016/j.prosdent.2024.09.017
  66. Zhao ZY, Li L, Bai PK, et al. The heat treatment influence on the microstructure and hardness of TC4 titanium alloy manufactured via selective laser melting. Materials (Basel). 2018;11(8):1318. doi: 10.3390/ma11081318
  67. Marie A, Keeling A, Hyde TP, et al. Deformation and retentive force following in vitro cyclic fatigue of cobalt-chrome and aryl ketone polymer (AKP) clasps. Dent Mater. 2019;35(6):E113-E121. doi: 10.1016/j.dental.2019.02.028
  68. Vallittu PK, Kokkonen M. Deflection fatigue of cobalt-chromium, titanium, and gold alloy cast denture clasp. J Prosthet Dent. 1995;74(4):412-419. doi: 10.1016/s0022-3913(05)80384-1
  69. Mahmoud A, Wakabayashi N, Takahashi H, Ohyama T. Deflection fatigue of Ti-6Al-7Nb, Co-Cr, and gold alloy cast clasps. J Prosthet Dent. 2005;93(2):183-188. doi: 10.1016/j.prosdent.2004.11.011
  70. Chen JB, She Y, Du XY, Liu YF, Yang Y, Yang JS. Influence of oxygen content on selective laser melting leading to the formation of spheroidization in additive manufacturing technology. RSC Adv. 2024;14(5):3202-3208. doi: 10.1039/d3ra08627e
  71. Barriobero-Vila P, Artzt K, Stark A, et al. Mapping the geometry of Ti-6Al-4V: From martensite decomposition to localized spheroidization during selective laser melting. Scr Mater. 2020;182:48-52. doi: 10.1016/j.scriptamat.2020.02.043
  72. Yin A, Yu WL, Li WB, et al. Microstructural and thermal relaxation of residual stress in dual peened TA15 titanium alloy fabricated by SLM. Mater Charact. 2024;218:114496. doi: 10.1016/j.matchar.2024.114496
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