Dental diamond burs made with a new technology.
BACKGROUND
Conventional diamond burs show several limitations such as the heterogeneity of grain shapes, the difficulty of automation during fabrication, the decrease of cutting effectiveness due to repeated sterilization, and short lifetime. An additional shortcoming may be represented by the potential release of Ni+2 ions from the metallic binder into the body fluids.


OBJECTIVE
This study investigated a new diamond rotative instrument made of a continuous diamond film obtained by chemical vapor deposition (CVD). This bur, characterized by a pure diamond cutting surface without metallic binder between crystals, was compared with a conventional diamond bur.


METHODS
Cutting tests were followed by SEM examination and electron microprobe analysis (EMA) to trace metallic residues both at the surface of the bur and the substrate.


RESULTS
EMA demonstrated that the metals Ni, Cr, Si, and Fe were present in the metallic binder matrix of the conventional bur and could be smeared on the surface of the substrate during cutting. SEM showed that significant loss of diamond particles occurred during cutting. On the other hand, no discrete particles sheared off the CVD bur. The smearing of the metallic binder cannot occur using the new bur.


CONCLUSIONS
The new CVD bur not only proves to be more efficient in its cutting ability and longevity, but also excludes the risk of metal contamination. This last aspect concerns both the pollution of the oral environment and the contamination of the ceramic during the laboratory manufacturing of dental restorations.
Borges
C F
CF
University of Minnesota, Department of Mechanical Engineering, Minneapolis 55455, USA. cfmb@me.umn.edu
Magne
P
P
Pfender
E
E
Heberlein
J
J
D003762:Dental Instruments; D003764:Dental Materials / Q000032:analysis / Q000737:chemistry*; D018130:Diamond / Q000032:analysis / Q000737:chemistry*; D004577:Electron Probe Microanalysis; D004867:Equipment Design; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties; D013674:Technology, Dental / Q000379:methods*
D003764:Dental Materials; D018130:Diamond