1902 Clinical Comparison of Conventional vs. Spectrophotometric Shade Matching for Posterior Crowns
S. PAUL, A. PETER, R. JUNG, C. RAMEL, F. WETTSTEIN, V. GOH, A. HAGMANN, and C.H.F. HAMMERLE, University of Zurich, Switzerland
Objectives: To test the shade matching of PFM restorations with the adjacent dentition if the restorations were fabricated either using conventional visual shade matching or using a new spectrophotometric shade matching system. Methods: The samples of a Vita Classic shade guide were measured with the spectrophotometer to determine the CIE L*a*b* coordinates. In group A graduate students with a negative history of visual color deficency independently selected the Best Match to the tooth needing a restoration on 20 pairs of posterior teeth (øBM, øDEBM). Each patient was standing against a white wall with ceiling lighting of 5000 K. In group B 20 pairs of posterior teeth were measured using a reflectance spectrophotometer (øBM-SP, øDE-SP). CIE Lab coordinates were directly recorded on the SP's 18x13 square mm detector area using a standard light source (l = 400-720 nm). Resulting conventional and spectrophotometric PFM’s were tested intraorally for best match with the adjacent tooth using conventional shade matching (øBM-C, øDE-C) vs. spectrophotometric measuring (øBM-SPC, øDE-SPC) . Results: mean DE values for preoperative shade taking were significantly higher for the conventional compared to the spectrophotometric method (Mann-Whitney, p< 0,05).Postoperatively, no statistical difference was revealed between shade taking methods (Mann-Whitney, p> 0,4). Conclusions: Spectrophotometric shade matching could be used efficiently by graduate students for fabrication of posterior PFM restorations.