Study on the densification drilling mechanism and evaluation system of polyurethane foam as a simulated material for alveolar bone

To improve the quality of cavity preparation in alveolar bone is crucial for enhancing higher primary implant stability. Therefore, compared to conventional drilling, a densification drilling method for alveolar hole preparation was proposed to form dense layer within machined hole. To elucidate the mechanism of material densification formation, a series of basic experiments were performed with polyurethane foam composites. Then, the processed holes were scanned using X-ray microscopy, and the slices were processed via image algorithm. In addition, the two- and three-dimensional quantitative models were established to explore the mapping relationship between machining parameters and the degree of densification. Experimental results demonstrate that this method maximizes the retention of raw materials, thereby enhancing the initial stability of the implant. The phenomenon is attributable to unique machining mechanism of densification drilling, where material removal is primarily governed by continuous extrusion and friction rather than shear action. And, based on the quantitative model of densification, the optimal parameter combination of 1500 rpm, 24 mm/min can be obtained. The results of the study on the formation mechanism and evaluation system of densification drilling can provide theoretical support for clinical procedures.