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

•We have designed a PTOF rangefinder for short distances.•We have calculated its performance.•We have built the new system.•We have tested its actual performance.

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.