Multistepped Drill Design for Single-Stage Implant Site Preparation: Experimental Study in Type 2 Bone

Purpose: To evaluate an experimental multistepped drill for single-stage implant site preparation by means of real-time analysis of thermal variations during and postdrilling, and by implant stability evaluation. Materials and Methods: Temperature and time were recorded in real time by paired microprobe thermocouples during simulated osteotomy in type 2 bone similes at the cortical and cancellous zones. Three different drilling groups with a new multistepped drill design were compared: Control (2-mm diameter pilot drill+3.3-mm three-stepped drill+4.1-mm three-stepped drill); Test A (3.3-mm three-stepped drill); and Test B (4.1-mm three-stepped drill). Implants were inserted, and implant stability was evaluated with the Perio Test Value (PTV). Two-way anova was used to test the independent effects of osteotomy and implant diameter on temperature and stability. Results: All the drills induced thermal changes without significant differences between groups (p>.05). Drilling in cortical bone produced significant increase of the temperatures in a range of 1.8±0.9°C compared with drilling in cancellous bone (p<.05). ΔT temperatures were significantly higher for test groups in cortical and cancellous bone (p<.05); ΔT₁₀ for all groups showed a reduction of the temperature in a range of 1.7±0.3°C without significant differences between groups (p>.05); the mean time to accomplish drilling was significantly longer in the control group (p<.05); test groups took 10±0.3 seconds less to reach the required drilling depth. PTV values were higher in test groups compared with controls (p<.05). Conclusions: The multistepped drills used for single-stage implant site preparation Increase temperature as in comparison with a conventional incremental protocol; Induce the temperature increment in cortical bone compared with the cancellous bone; Reduce drilling time when a multistepped drill is used alone; and Increase implant stability twofold compared with a conventional incremental protocol.