EXPERIMENTAL ASSESSMENT OF THE BONE CAVITY HEATING AT DIFFERENT SPEEDS DURING PREPARATION FOR DENTAL IMPLANTATION

Abstract

The objective of the study was to evaluate the level of bone tissue heating experimentally during various high-speed and slow-speed protocols for the preparation of the bone cavity for dental implantation. Materials and Methods: 8 samples of skeletonized veal ribs (length 10.00–12.00 cm and thickness 1.50–2.00 cm) were dissected, four cuts were made according to different speed protocols at a distance of 1.00–1.50 cm from each other. The duration of each manipulation was 15 s. The Lindemann guide drill with a diameter of 2.20 mm (apex diameter – 1.70 mm) and length of 35.00 mm (with a limiter) was used for work without any cooling of the operating field. The following preparation parameters were applied: 1000 rpm, 300 rpm, 100 rpm, and 50 rpm; in all cases, the torque of the surgical drill was 35 N×cm. Bone tissue temperature was measured with an electronic contact thermometer before and immediately after manipulation. Results: Measurements showed that heating of bone tissue was observed in almost all applied protocols of bone tissue preparation. This fact can represent a danger to the patient by increasing the risk of developing localized osteomyelitis of the alveolar ridge due to trauma. This, in turn, can increase the risk of the installed dental implant disintegration or the development of fiber integration. During 15 seconds of preparation at a speed of 1000 rpm, the bone tissue heated up the most; the average temperature increase was 5.64 ± 2.23 °С (М = 4.60 °С), the value – from 3.00 to 10.30 °С. At the speed of 300 rpm, heating was less – by 3.79 ± 1.76 °C (M = 3.80 °C), the values were in the range of 1.10–6.40 °C. At the speed of 100 rpm, the heating of the bone canal was 2.99 ± 1.36 °С (М = 2.65 °С), in the range of values within 1.10–5.20 °С. During preparation at the speed of 50 rpm, the heating of bone tissue was minimal – 2.06 ± 0.66 °С (М = 1.95 °С), the value was recorded in the range of 1.00–3.20 °С. Considering that in most experimental studies, the time of preparation of bone tissue (or its model) was longer – 1 min, while in our study such prolongation of interaction with bone tissue was impractical (the bone cavity was fully prepared in 15 s) and the interaction of the cutter with the surrounding tissue was minimized, a decision was made to create a mathematical regression model of the thermal reaction of bone tissue during such treatment. The application of the created regression mathematical model of bone tissue heating during preparation without cooling for 1 min showed that the use of surgical drills at the speed of 1000 rpm and torque of 35 N×cm could lead to critical heating in 62.50% of cases, at the speed of 300 rpm min and a torque of 35 N×cm – in 50.00% of cases, at a speed of 100 rpm and torque of 35 N×cm – in 25.00%. The use of the speed of 50 rpm and torque of 35 N×cm without water cooling did not impose the risk of critical heating of bone tissue. Conclusions: the experimental data on the bone tissue heating when using different speeds during preparation without cooling the operating field were obtained. The safest method used was the scheme of 50 rpm with a torque of 35 N×cm.