The need for a speed increasing contra-angle, in combination with an electric micromotor, should not be underestimated for precise tooth preparation. The combination of a speed increasing contra-angle and micromotor gives complete speed control, improved tactile sensation, and a smoother running bur than a turbine. All of these advantages equate to more precise margins and potential for improved overall clinical results.
When using a foot pedal operated turbine, most clinicians find it operates well at full speed, but when the speed is reduced for fine margin preparation, torque is lost and the bur stops turning, this is particularly disruptive when trying to achieve a very precise margin.
The speed increasing contra-angle uses the same burs as a turbine, however with the advantage of delivering greater speed control right throughout the process; high speed, high torque for gross reduction; slow speed, high torque for fine margin preparation; the whole procedure with one contra-angle. Additionally, a speed increasing contra-angle can be used in short bursts at very slow speed to prepare palatal margins without water, which is impossible with a turbine.
Conclusion
In conclusion, I would recommend all clinicians take advantage of the benefits of a speed increasing contra-angle in conjunction with a micromotor and see for themselves the advantages it provides.