Dental diamond burs made with a new technology

Statement of problem. Conventional diamond burs show several limitations su ch as the heterogeneity of grain shapes, the difficulty of automation durin g fabrication, the decrease of cutting effectiveness due to repeated steril ization, and short lifetime. An additional shortcoming may be represented b y the potential release of Ni+2 ions from the metallic binder into the body fluids. Purpose. 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 bind er between crystals, was compared with a conventional diamond bur. Material and methods. Cutting tests were followed by SEM examination and el ectron microprobe analysis (EMA) to trace metallic residues both at the sur face of the bur and the substrate. Results. EMA demonstrated that the metals Ni, Cr, Si, and Fe were present i n the metallic binder matrix of the conventional bur and could be smeared o n the surface of the substrate during cutting. SEM showed that significant loss of diamond particles occurred during cutting. On the other hand, no di screte particles sheared off the CVD bur. The smearing of the metallic bind er cannot occur using the new bur. Conclusion. The new CVD bur not only proves to be more efficient in its cut ting ability and longevity, but also excludes the risk of metal contaminati on. This last aspect concerns both the pollution of the oral environment an d the contamination of the ceramic during the laboratory manufacturing of d ental restorations.