Recent advances in dental optics – Part II: Experimental tests for a new intraoral scanner

The object of this paper is testing the performance of a new device for 3D oral scanning: a two channel PTOF (pulsed time-of-flight) laser scanner, designed for dental and industrial applications in the measurement range of zero to a few centimetres. The application on short distances (0-10 cm) has entailed the improvement of performance parameters such as single shot precision, average precision and walk error up to mm-level and to μm-level respectively. The single-shot precision (σ-value) has resulted to range from 43 to 63 ps (9-10 mm), having considered the measurement range (6.5-10 mm) corresponding to 1-2 V signal; this result agrees well with estimates made from simulations. The average precision has resulted to be dependent on the number of measurements and can reach a value equal to ±25 μm, whenever the measurements frequency is sufficiently high. For example, if the required scanning speed is 1000 points/s and the required average precision is ±25 μm, then a pulses frequency of 30-50 MHz is needed, considering signal amplitude varying between 1-2 V. On the whole, the performance of this new device, based on PTOF has proven to be adequate to its employment in the field of restorative dentistry.