Fatigue properties of removable partial denture clasps fabricated by selective laser melting followed by heat treatment

Nuttaphon Kittikundecha; Yuka Kajima; Atsushi Takaichi; Hla Htoot Wai Cho; Hein Linn Htat; Hisashi Doi; Hidekazu Takahashi; Takao Hanawa; Noriyuki Wakabayashi

doi:10.1016/j.jmbbm.2019.06.010

Fatigue properties of removable partial denture clasps fabricated by selective laser melting followed by heat treatment

J Mech Behav Biomed Mater. 2019 Oct:98:79-89. doi: 10.1016/j.jmbbm.2019.06.010. Epub 2019 Jun 10.

Authors

Nuttaphon Kittikundecha¹, Yuka Kajima², Atsushi Takaichi³, Hla Htoot Wai Cho¹, Hein Linn Htat¹, Hisashi Doi⁴, Hidekazu Takahashi⁵, Takao Hanawa⁴, Noriyuki Wakabayashi¹

Affiliations

¹ Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.
² Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan; Department of Dental Materials, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-8310, Japan.
³ Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan. Electronic address: a.takaichi.rpro@tmd.ac.jp.
⁴ Metallic Biomaterials, Biomedical Materials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo, 101-0062, Japan.
⁵ Department of Oral Biomaterials Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.

PMID: 31203100
DOI: 10.1016/j.jmbbm.2019.06.010

Abstract

The aim of the study was to investigate the effect of post-heat treatment on the microstructures and fatigue strengths of Co-Cr-Mo (CCM) clasps prepared by selective laser melting (SLM). Clasp specimens and rod-shaped specimens were fabricated by SLM using CCM powders with different angulations (0°, 45°, and 90°). Two heat treatment conditions were used: 1 and 6 h at 1150 °C in an argon atmosphere followed by cooling in a furnace. Subsequently, the fatigue strength and microstructure were investigated. The results revealed that for the control group, the mean fatigue life was different when building angulations were changed as manifested by the control-90 specimen, which exhibited the highest fatigue life, followed by control-45 and then control-0. One-hour heat treated samples showed higher fatigue strength in all axes than the 0°- and 45°-axes control samples and lower fatigue strength than the 90°-axes control samples. The survival rate after heat treatment for 1 h exhibited no significant difference in all the axes. In terms of microstructure, after heat treatment, the samples showed homogeneous equiaxed grain and randomized texture in all angulations. Therefore, using a post-heat treatment can reduce the anisotropy effect on the microstructure and fatigue strength due to homogenized microstructure.

Keywords: Anisotropy effect; Clasp; Co–Cr–Mo alloy; Fatigue strength; Heat treatment; Selective laser melting.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Dental Clasps*
Hot Temperature*
Lasers*
Mechanical Phenomena*
Phase Transition
Stress, Mechanical