The Reproducibility and Applicability of an EFD(®) Dispenser in the Prosthetic Technology of Maxillofacial Prostheses.

A reproducible method of dosing pigments can be beneficial and more efficient in the current colour matching procedure in maxillofacial prosthetics. In this study the reproducibility and applicability for pigment dosing of a commercial available EFD(®) dispenser were tested. The reproducibility of a Performus™ II type EFD(®) dispenser was tested by repeating dosing experiments with a set of eight syringes filled with pigment pastes (Factor 2; Flagstaff, USA). To evaluate conventional colour matching, four conventionally colour matched samples were polymerized and compared to the original ones. To investigate the reproducibility of the dispenser in practice, a fifth recipe was dispensed 10 times and colour differences were evaluated visually and as well calculated from measurements with a colour and translucency meter (CTM, PBSensortechnology bv). All dispensed amounts of pigment pastes showed a coefficient of variation in weight of less than 10 %. Evaluating the reproductions of four skin batches compared to the original batches, a ∆E2000 colour difference of 3-7 was measured. Evaluating ten reproductions of one skin coloured batch made with the dispenser, color difference ∆E2000 values compared to the average L*a*b* values, were less than 2 and no visual colour differences could be estimated. Conform these results, low colour differences could be measured with the CTM, indicating no visually observable consequences. Despite the estimated coefficient of variation, the reproducibility of the EFD(®) dispenser in terms of colour difference ∆E2000 of successive dispensing is applicable for colour reproduction in facial prosthetics. Segregation of the current color pastes in due time needs to be taken into consideration.