DEVELOPMENT OF ULTRASONIC DENTAL TIPS BY POWDER INJECTION MOLDING

Abstract

Modern endodontic microsurgery requires state-of-the-art instruments and materials that match biological concepts with clinical practice. One of the important instruments is the ultrasonic endodontic tip, fabricated in the past utilizing conventional manufacturing technologies such as machining, drilling, bending, and diamond coating: In this study, ultrasonic dental scaler tips and endodontic tips are redesigned to take advantage of the near-net-shaping and mass-production capability of powder injection molding (PIM). A wax-polymer-based binder system and stainless steel powder was used as feedstock with injection molds designed and machined to produce the dental tips by PIM. By using computer aided engineering (CAE) software, the mold-filling stage was analyzed and the results applied in the mold design. Filling balance in the mold was checked using low-density polyethylene (LDPE) and the PIM feedstock. After debinding and sintering, the PIM parts were evaluated by a vibration test to check functionality over the required operational range. Some minor issues such as powder-binder separation at the gate and flashing at the air vent were identified, but with adjustments via both simulation and experiments, the product was successful and confirmed that PIM is a viable mode of fabrication for ultrasonic dental tips.