Influence of Multiple Used Implant Drills on Their Cutting Performance and Fracture Resistance

Abstract

This study aimed to analyze the influence of multiple uses of zirconia implant drills on their cutting performance and bending strength. The hypothesis was that drill usage and sterilization cycles would not affect drilling time or flexural strength. Sixty zirconia twist drills from Z-Systems were used to drill in the angulus mandibulae region of fresh porcine jaws. The drills were divided into four groups based on the cycle count, and the drilling time was measured. Bending strength tests were conducted using a universal testing machine, and statistical analysis was performed using ANOVA tests. The results showed that drilling times followed a normal distribution, and significant differences were observed in drilling times between group 1 and the other groups for the pilot drill. However, no significant differences were found for ø3.75 mm and ø4.25 mm drills, and drilling times also varied significantly among different drill diameters, regardless of the cycle count. Flexural strength did not significantly differ among drill diameters or sterilization cycles. Overall, using and sterilizing zirconia implant drills had no significant impact on drilling time or flexural strength. Nevertheless, drilling times did vary depending on the diameter of the drill. These findings provide valuable insights into the performance and durability of zirconia implant drills, contributing to the optimization of dental implant procedures.

Assessment of Thermal Osteonecrosis during Bone Drilling Using a Three-Dimensional Finite Element Model

“…While numerous technical studies have explored methods to mitigate the heat effects on bone, such as utilising coolant irrigation, optimising drill bit geometry [9], enhancing wear resistance [47], implementing step-power drilling [48], etc., there is no conclusive evidence to indicate that irrigation cooling is universally adopted as a standard practice, despite strong recommendations from major implant manufacturers. However, clinically, irrigation cooling is standard practice and is strongly advocated for by leading implant manufacturers [49][50][51][52].…”

“…In addition, the contact interaction properties must be defined for the contact pair. An assumption is made that Coulomb's friction law governs the friction behaviour between the drill bit and bone; the coefficient of friction is assumed to be 0.3 [9].…”

“…It has been shown that temperatures over 50 °C are associated with irreversible changes in bone structure and physical properties [1,2]. Then, the necrotic bone is resorbed through osteoclast activity, posing potential risks to the stability of bone screws and pins and ultimately leading to the failure of the fracture repair or implant fixation [3][4][5][6][7][8][9]. Consequently, some studies have focused on the rise in temperature during bone drilling and the associated necrosis phenomenon.…”

Assessment of Thermal Osteonecrosis during Bone Drilling Using a Three-Dimensional Finite Element Model

“…In addition, the contact interaction properties must be defined for the contact pair. An assumption is made that Coulomb’s friction law governs the friction behaviour between the drill bit and bone: the coefficient of friction is assumed to be 0.3 [ 9 ]. The thermal conductivity for cortical bone and drill bit are 0.452 and 16.2 (W/m·k), respectively [ 39 , 40 ].…”

“…It has been shown that temperatures over 50 °C are associated with irreversible changes in bone structure and physical properties [ 1 , 2 ]. The necrotic bone is resorbed through osteoclast activity, posing potential risks to the stability of bone screws and pins and ultimately leads to the failure of the fracture repair or implant fixation [ 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. Consequently, some studies have focused on the rise in temperature during bone drilling and the associated necrosis phenomenon.…”