The effect of multilayer filtered arc coatings on mechanical properties, corrosion resistance and performance of periodontal dental instruments

A large-area filtered arc deposition (LAFAD) process was used to deposit various multi-layer cermet coatings on dental scalers made of martensitic stainless steel. A custom mechanical stroking device was used to include features capable of simulating the load and motion of dental scalers against enamel or dentin tooth surfaces in an aqueous environment. Subjecting the coated instruments to vibratory tumbling in a vat containing cellulose filler and an abrasive tested the abrasion resistance of the coating. The working edge wear was then investigated by means of optical and electron microscopy as well as by metallurgical cross-section profile analysis. Coating adhesion was determined by measuring delamination during Rockwell testing. Corrosion resistance of dental instruments with multi-layer coatings was studied by subjecting the instruments to repeated conventional autoclave sterilization procedures. Comparison of the laboratory tests with the field testing results in dental clinical practice is presented. The mass production yield of high-quality scalers with LAFAD coatings is discussed.