Comparative Analysis of the Histological Characteristics of Bone Tissue Following Implant Drill Preparation Under Various Parameters: An In Vitro Study

<b>Purpose:</b> This study aimed to compare the histological characteristics of bone tissue following drilling with three implant systems under different rotational speeds and cooling conditions. <b>Methods:</b> A total of 54 implant bed preparations were performed in four swine ribs using three implant systems: Hiossen ET (Hiossen, Fairfield, NJ, USA), Paltop (Burlington, MA, USA), and Anyridge (Megagen, Daegu, Republic of Korea). Drilling was performed at three speeds (800, 1200, and 1500 rpm) under three cooling conditions: saline at room temperature, saline cooled to 4 °C, and no cooling. Histological evaluation was conducted using a Nikon Eclipse 80i fluorescence microscope (Nikon, Tokyo, Japan) with DAPI and rhodamine staining. Observations were performed at 40× magnification, focusing on the osteotomy wall and surrounding tissue. The samples were assessed based on surface smoothness, compressed tissue presence, carbonization, and adjacent tissue damage. Statistical analysis was performed using the Kruskal-Wallis test with Dunn's post hoc comparisons to evaluate differences among experimental conditions. <b>Results:</b> The results demonstrated that the Hiossen ET system achieved optimal bone bed quality at 1200 rpm with saline cooling at 4 °C, producing the smoothest osteotomy walls and minimal thermal damage (<i>p</i> = 0.003). The Paltop system performed best at 800 rpm with 4 °C cooling, showing reduced tissue compression and fewer microcracks (<i>p</i> = 0.012). The Anyridge system exhibited the most favorable outcomes at 1200 rpm with saline cooling at room temperature, minimizing soft tissue remnants and preserving bone integrity (<i>p</i> = 0.021). Across all systems, the absence of cooling significantly increased thermal damage, carbonization, and tissue fragmentation, particularly at 1500 rpm (<i>p</i> < 0.001). <b>Conclusions:</b> The use of lower rotational speeds with effective cooling minimized tissue trauma and improved bone bed integrity. Further clinical validation is necessary to confirm the applicability of these results in human bone.