Thermal effects of various drill materials during implant site preparation—Ceramic vs. stainless steel drills: A comparative in vitro study in a standardised bovine bone model

Abstract

Objectives The aim of this study was to evaluate thermal effects of ceramic and metal implant drills during implant site preparation using a standardised bovine model. Material and Methods A total of 320 automated intermittent osteotomies of 10‐ and 16‐mm drilling depths were performed using zirconium dioxide‐based and stainless steel drills. Various drill diameters (2.0/ 2.2, 2.8, 3.5, 4.2 mm ∅) and different cooling methods (without/ with external saline irrigation) were investigated at room temperature (21 ± 1°C). Temperature changes were recorded in real time using two custom‐built multichannel thermoprobes in 1‐ and 2‐mm distance to the osteotomy site. For comparisons, a linear mixed model was estimated. Results Comparing thermal effects, significantly lower temperatures could be detected with steel‐based drills in various drill diameters, regardless of drilling depth or irrigation method. Recorded temperatures for metal drills of all diameters and drilling depths using external irrigation were below the defined critical temperature threshold of 47°C, whereas ceramic drills of smaller diameters reached or exceeded the harmful temperature threshold at 16‐mm drilling depths, regardless of whether irrigation was applied or not. The results of this study suggest that the highest temperature changes were not found at the deepest point of the osteotomy site but were observed at subcortical and deeper layers of bone, depending on drill material, drill diameter, drilling depth and irrigation method. Conclusions This standardised investigation revealed drill material and geometry to have a substantial impact on heat generation, as well as external irrigation, drilling depth and drill diameter.

An in vitro study on the impact of the torque after repeated use of the implant handpiece: An original research

“…In actual clinical trials, a saline solution is injected to reduce the heat generation of bone tissue. 19 In addition, the initial stability of the implant can be maintained through stepwise torque placement rather than by applying continuous force.18,19 Though, in this study, the output torque was measured in a laboratory environment, which is different from the clinical placement environment. To calculate more torque values, additional experiments with various torque values of implants from other companies are required.…”

Effect of repeated use of an implant handpiece on an output torque: An in-vitro study

“…Low torque during implant placement provides insufficient torque to obtain initial fixation of the implant, and excessive torque may generate heat in the surrounding bone tissue, leading to bone necrosis. 15 16 17 Neugebauer et al 1 reported the possibility that the implant may fail if the output torque is more than 35 Ncm during implant placement and that the placement torque and implant stability are related. Strietzel et al 18 reported that a high output torque could lead to a high bone resorption rate.…”

Drilling‐ and withdrawing‐related thermal effects of implant site preparation for ceramic and stainless steel twist drills in standardized bovine bone

“…For vertical dislocation measurement and program control, an external linear potentiometer (Linear Potentiometer 600 Series, Type 9615R5.1KL2.0, BEI Sensors, Goleta, CA) was used. In correspondence with previous investigations, 29–31,35 two drilling sequences (10 and 16 mm) with predefined parameters (dwell time, depth control, and drilling/withdrawing feed rate) were programmed. Ten millimeters drilling sequences were programmed with 27.6 s (drilling time 17.3 s, withdrawing time 10.3 s) and 16‐mm drilling procedures with 43.5 s (drilling time 27.1 s, withdrawing time 16.4 s).…”

“…The computer‐based temperature measurement system (SHTM‐Temperature Measurement System, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria) was software‐controlled (DASYLab® Software 5.0, Measurement Computing Corporation, Norton, MA) and included an ADC‐converter (Analog‐to‐digital‐converter; NI DAQCard™‐6062 E, National Instruments™, Austin, TX) and a measurement amplifier (SHU‐Measurement Amplifier, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria). For obtaining real‐time temperature values in multiple depths simultaneously, NTC‐detected signals were converted after calibration against traceable standards 29–31,35 . The temperature data recording started 10 s before the surgical procedure and ended 25 s after the withdrawing process.…”

“…With the aim of further investigating, the osteotomy process regarding specific materials and factors contributing to implant complications, in vitro temperature monitoring of surgical bone procedures was introduced and established 28–35 . As a result, numerous aspects with respect to the preparation of bone have been explored, revealing the impact of parameters such as drill diameter, 29,30 drill geometry and design, 36–39 multiple drill use, 40,41 irrigation, 30,31,33,42 surgical technique, 34,43,44 and drill material 35,45 on heat generation. Investigations focusing on the osteotomy process and time‐related temperature increase revealed the highest temperature changes being strongly associated with a late time period during the surgical procedure 31,33,46 and demonstrated the influence of surgical drilling depth and irrigation mode on the time of occurrence of the maximum temperature 31 .…”