Factors influencing the shade matching performance of dentists and dental technicians when using two different shade guides

In recent years increased patient aesthetic expectations have brought about closer scrutiny of shade taking and communication processes with the aim of increasing the chances of success of obtaining good indirect restoration appearance. When shade matching, the most popular approach is to match the shade of the natural dentition using a shade guide to specify the shade of the final restoration before fabrication. A recent alternative approach is to also specify the shade of the tooth preparation to facilitate its replication in the die upon which the restoration will be made. Objective: To assess (1) the colour vision ability of a sample of dentists and dental technicians and correlate this to their shade matching performance in a simulated clinical situation, and (2) the accuracy and reproducibility of shade matches using two shade guides. Design: In vitro study. Method: Consenting dentists and dental technicians within Dundee Dental School and Hospital undertook a Farnsworth-Munsell 100 (FM-100) Hue test and matched (on two separate occasions) the shades of six prepared extracted teeth, containing either a veneer or crown preparation, using both the IPS Natural Die Material shade guide (Ivoclar Vivadent) (IPS) and the Vitapan Classical shade guide (VITA Zahnfabrik) (VC). Results: Eighteen dental technicians (16 males and 2 females) and 40 dentists (21 males and 19 females) completed the study. The raw data revealed that many subjects were inconsistent in their approach to shade matching. The IPS guide afforded greater reproducibility. No significant effects (p >0.05) of subject gender and age upon overall shade matching performance were demonstrated. Performance in the FM-100 Hue test did not statistically affect (p >0.05) the outcome of matching using the guides. Conclusions: Within the limitations of this study, (a) the FM-100 Hue test was not a good predictor of dental shade matching performance, and (b) both guides performed well in the areas of shade they covered, with the Vita Classical guide matching well shades of natural unstained teeth and the IPS guide matching more closely stained/discoloured preparations.