## 1 Introduction  
Drill wear is a phenomenon determined by the detachment of particles during the preparation of implant sites that can interfere with the process of bone healing. Considering that all materials are subject to wear and chemical attack by disinfectants, it would be desirable to have a biocompatible drill that is not susceptible to attack by the disinfectants used in clinical practice. The healing of peri-implant bone is a complex phenomenon that involves the proliferation and differentiation of pre-osteoblasts into osteoblasts. Periosteal and endosteal activity also contributes to the production of the osteoid matrix, which is followed by mineralization and organization of the bone-implant interface [1]. The success of implant surgery depends on the bone and soft tissue healing after the process of implant site preparation [2]. One of the key factors in implant success is to keep the osteotomy process as atraumatic as possible for fast, optimal recovery and healing. One of the most important factors in minimizing trauma during osteotomy is to control heat generation with irrigation, but also by utilizing drills that will cut through bone in an efficient and minimally invasive manner [3; 4]. Even after a single use, drills will show signs of wear and start to lose their sharpness and cutting efficiency [5; 6]. A slightly damaged or dulled drill will not only lose its cutting efficiency, but also overheat bone, leading to bone necrosis, poor healing, and an ill-defined osteotomy with a poor initial implant stability [7; 8]. Among the materials used for the manufacturing of implant drills is steel, whose structural integrity can be affected by disinfectants and cleaning agents. When coming into contact with chemical disinfectants, an oxidation process takes place on the drill, giving rise to corrosion products and the release of metal particles and ions to the peri-implant tissues, which can cause inflammation, increased osteoclasticity, and subsequent implant failure [9; 10].  
The phenomenon and mechanism by which the reuse of an implant drill can be a source of metal particles or ions in implant bed preparation have not been evaluated in the literature. Metal particles and ions are known to induce osteolysis, so it is important to avoid potential sources of metal ions and particles for the long-term survival of dental implants. The reuse of drills, repeated cleansing, and sterilization causes them to lose their sharpness and trigger the corrosion process. As a result, there is a loss of cutting efficiency, thus making it possible to leave metal particles and ions in the bone. Furthermore, the loss of cutting efficiency increases the friction between the bone and drills and elevates the osteotomy temperature, leading to bone cell death and implant failure. An alternative drill material to steel is zirconium dioxide, also known as zirconia, which is a ceramic and belongs to the category of materials called inert metal oxides. They are also used as dental implant materials [11]. Zirconia is bio-inert, and has excellent corrosion resistance, superior biocompatibility, high wear resistance, and high fracture resistance values [12; 13]. Repeated disinfection and sterilization cycles can lead to undesirable changes in the physical properties of the instruments, such as a loss of structure, sharpness, and corrosion [5]. The purpose of this study is to analyze the effects of chemical disinfection and autoclave sterilization on zirconium oxide ceramic drills vs. steel drills by scanning electron microscopy and energy dispersion X-ray microanalysis. The null hypothesis of this study is that there will be no difference in surface alterations between zirconia and steel drills as a result of disinfection and sterilization procedures.