The effect of abrading and cutting instruments on machinability of dental ceramics

• Published in: Journal of materials science. Materials in medicine Vol. 29; no. 3; pp. 34 - 8
• Main Authors: Sakoda, Satoshi, Nakao, Noriko, Watanabe, Ikuya
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.03.2018; Springer Nature B.V
• Subjects: Abrasion; Biomaterials; Biomaterials Synthesis and Characterization; Biomedical Engineering and Bioengineering; Biomedical materials; Ceramics; Ceramics - chemistry; Chemistry and Materials Science; Composites; Cutting force; Dental Equipment - adverse effects; Dental Materials - chemistry; Dental Porcelain - chemistry; Dental Restoration Repair - instrumentation; Dental restorative materials; Diamond - chemistry; Diamond machining; Equipment Design; Glass; High speed; Humans; Machinability; Materials research; Materials Science; Materials Testing - instrumentation; Materials Testing - methods; Mechanical properties; Natural Materials; Physical properties; Polymer Sciences; Product design; Programmable logic controllers; Regenerative Medicine/Tissue Engineering; Silicon carbide; Sintering; Surface Properties; Surfaces and Interfaces; Thin Films; Turbine instruments; Turbines; Wheels; Zirconia; Zirconium - chemistry; Zirconium dioxide
• ISSN: 0957-4530; 1573-4838
• DOI: 10.1007/s10856-018-6031-y

The aim was to investigate the effect of machining instruments on machinability of dental ceramics. Four dental ceramics, including two zirconia ceramics were machined by three types (SiC, diamond vitrified, and diamond sintered) of wheels with a hand-piece engine and two types (diamond and carbide) of burs with a high-speed air turbine. The machining conditions used were abrading speeds of 10,000 and 15,000 r.p.m. with abrading force of 100 gf for the hand-piece engine, and a pressure of 200 kPa and a cutting force of 80 gf for the air-turbine hand-piece. The machinability efficiency was evaluated by volume losses after machining the ceramics. A high-abrading speed had high-abrading efficiency (high-volume loss) compared to low-abrading speed in all abrading instruments used. The diamond vitrified wheels demonstrated higher volume loss for two zirconia ceramics than those of SiC and diamond sintered wheels. When the high-speed air-turbine instruments were used, the diamond points showed higher volume losses compared to the carbide burs for one ceramic and two zirconia ceramics with high-mechanical properties. The results of this study indicated that the machinability of dental ceramics depends on the mechanical and physical properties of dental ceramics and machining instruments. The abrading wheels show autogenous action of abrasive grains, in which ground abrasive grains drop out from the binder during abrasion, then the binder follow to wear out, subsequently new abrasive grains come out onto the instrument surface (autogenous action) and increase the grinding amount (volume loss) of grinding materials.