[Shiau-ROC TAIWAN-P-4] Nobel bone density evaluation based on drilling torque value using a newly designed drill
[Abstract]
[Objective]
Bone density at the implant site is evaluated indirectly and subjectively by computed tomography (CT) evaluation and the drilling sensation of implant socket. Evaluation of implant site by drilling has been reported, however, the correlation between bone density and drilling torque value is not clear. In this study, we aimed to investigate bone density classification of cancellous bone using a newly designed drill.
[Method]
Experiment 1: Polyurethane cancellous bone-like blocks corresponding to Misch classifications D1-D4 were prepared (ASTM F1839-08). A φ3.0 mm reading drill (control 1, IDI Evolution, Italy) and a φ2.7 mm reading drill (control 2, original manufactured) were used as controls. A φ2.7 mm density measurement drill (original manufactured) was newly designed. Drilling torque value (DTV) of each drill was recorded by a surgical implant motor device (Surgic Pro2; Nakanishi inc., Japan). Measurement was performed at a speed of 35 rpm under continuous water irrigation, and the measurement depth was 3 mm (n =25). Experiment 2: Bovine ribs were prepared, and density measurement drill was used for evaluation. Gutta-percha points were marked on the bone at 1-2 cm intervals, and then multi-detector CT imaging was performed (slice thickness: 1mm). CT value and DTV of cancellous bone region were measured at each marked site. The obtained CT value was classified according to Misch classification, and the correlation between CT value and DTV was investigated.
[Results and Discussion]
In experiment 1, DTV of control 1 and density measurement drill were significantly different among all of D1-D4 (p<0.01), however, control 2 showed no significant difference between D3 and D4. In experiment 2, Misch D2 (n=87), D3 (n=92), D4 (n=133) and less than D4 (D5, n=52) were obtained based on CT value, however, there were no D1 site. Measurement of DTV using density measurement drill enabled D2-D5 density classification (p<0.05), and the CT value was positively correlated with DTV (r=0.86). These results indicate that a newly designed density measurement drill was able to classify bone density of cancellous bone despite of its narrow diameter, and may be useful for intraoperative bone density evaluation of implant treatment.
[Objective]
Bone density at the implant site is evaluated indirectly and subjectively by computed tomography (CT) evaluation and the drilling sensation of implant socket. Evaluation of implant site by drilling has been reported, however, the correlation between bone density and drilling torque value is not clear. In this study, we aimed to investigate bone density classification of cancellous bone using a newly designed drill.
[Method]
Experiment 1: Polyurethane cancellous bone-like blocks corresponding to Misch classifications D1-D4 were prepared (ASTM F1839-08). A φ3.0 mm reading drill (control 1, IDI Evolution, Italy) and a φ2.7 mm reading drill (control 2, original manufactured) were used as controls. A φ2.7 mm density measurement drill (original manufactured) was newly designed. Drilling torque value (DTV) of each drill was recorded by a surgical implant motor device (Surgic Pro2; Nakanishi inc., Japan). Measurement was performed at a speed of 35 rpm under continuous water irrigation, and the measurement depth was 3 mm (n =25). Experiment 2: Bovine ribs were prepared, and density measurement drill was used for evaluation. Gutta-percha points were marked on the bone at 1-2 cm intervals, and then multi-detector CT imaging was performed (slice thickness: 1mm). CT value and DTV of cancellous bone region were measured at each marked site. The obtained CT value was classified according to Misch classification, and the correlation between CT value and DTV was investigated.
[Results and Discussion]
In experiment 1, DTV of control 1 and density measurement drill were significantly different among all of D1-D4 (p<0.01), however, control 2 showed no significant difference between D3 and D4. In experiment 2, Misch D2 (n=87), D3 (n=92), D4 (n=133) and less than D4 (D5, n=52) were obtained based on CT value, however, there were no D1 site. Measurement of DTV using density measurement drill enabled D2-D5 density classification (p<0.05), and the CT value was positively correlated with DTV (r=0.86). These results indicate that a newly designed density measurement drill was able to classify bone density of cancellous bone despite of its narrow diameter, and may be useful for intraoperative bone density evaluation of implant treatment.