Development of dispersion layers for dental drills with reduced Nickel release
Sprache des Titels:
Objectives: Without rotating instruments, for example diamond-coated drills with a core made of stainless steel,
the dental routine would be unimaginable, since these are used in almost every dental activity and are thus
indispensable for the professional practice. Unfortunately, such drills release Nickel particles to a high content
into the cooling water of the drill. Values up to 1.3 mg/l Nickel were found by ICP ? OES in the cooling water of
the drillers which is of course also transferred into the patient?s oral cavity with possible severe negative effects.
Therefore, novel plating procedures have to be developed to increase the patients (and dentists) safety during
Methods: Dispersion layers with the hard metal Tungsten carbide (WC) particles on stainless steel blanks were
deposited following two synthesis routines (i) Plasma-Electrolytic Oxidation (PEO) and (ii) galvanic plating out
of a Watts bath. Both were accomplished using water-based electrolytes.
Results: In order to verify the dental applicability of the developed coatings, tests-drills were accomplished under
defined conditions on plastic teeth for the sake of reproducibility.
Commercially produced drills were compared with the newly plated ones by Scanning Electron Microscopy
(SEM), Atomic Force Microscopy (AFM) and the drilling cooling water was examined for heavy metal residues
using Inductively Coupled Plasma (ICP) analytics. The resulting grinding patterns in the plastic teeth were
investigated by light microscopy and SEM.
It could be shown that dispersion layers plated by a galvanic procedure showed a reduced Nickel release
compared to a commercial driller by factor 7.6 and 13.4 compared to PEO plated ones during dental treatments.
Conclusions: Following the clinical significance the Watts bath plated drillers showed a better WC particle distribution on the surface and better abrasive properties during the drilling experiments compared to PEO plated
drillers. In addition the Nickel release during dental use is much less from the galvanic treated ones. By optimising the plating condition from the Watts dispersion bath further novel drilling devices with significantly
reduced release of Nickel particles can be developed for the benefit of the patients.