Clasp fabrication using one-process molding by repeated laser sintering and high-speed milling.
OBJECTIVE
A single machine platform that integrates repeated laser sintering and high-speed milling for one-process molding has been developed.


METHODS
The Akers clasp was designed using the CAD system (DWOS Partial Frameworks, Dental Wings) and fabricated using repeated laser sintering and a high-speed milling machine (LUMEX Advance-25, Matsuura) with 50-μm Co-Cr particles (CAM clasp). As controls, cast clasps of the same forms were also prepared using conventional casting methods with a Co-Cr alloy and CP titanium Grade 3. After the surface roughness was measured, the gap distance between the clasps and the tooth die was assessed using the silicone film method. The initial retentive force and changes in retention up to 10,000 cycles were also measured. The data were analyzed using two-way ANOVA and Tukey's multiple comparison test (α=0.05).


RESULTS
CAM clasps exhibited significantly smoother surfaces than those of cast Co-Cr and CP Ti clasps (p<0.05). However, the gap distances of the CAM clasps were significantly greater than those of the cast clasps (p<0.05). The retentive forces of both CAM and cast Co-Cr clasps were significantly higher than those of CP Ti clasps. (p<0.05). The retention of CAM clasps demonstrated a constant or slight decrease from 1000 up to 10,000 cycles.


CONCLUSIONS
The CAM clasp made by repeated laser sintering and high-speed milling can be used effectively as an RPD component.
Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine, Yokohama, Japan. Electronic address: nakata-toyoki@tsurumi-u.ac.jp.
Toyoki
T
Nakata
Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine, Yokohama, Japan.
Hidemasa
H
Shimpo
Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine, Yokohama, Japan.
Chikahiro
C
Ohkubo
D017076:Computer-Aided Design; D003735:Dental Casting Technique; D016734:Dental Clasps; D017267:Dental Prosthesis Design / Q000379:methods*; D003781:Denture Retention; D007834:Lasers
Additive manufacturing; CAD/CAM; Clasp; Hybrid process; Retentive force