A comparison between a new visual method of colour matching by intraoral camera and conventional visual and spectrometric methods.

Objectives: The objective of this study was to evaluate the new colour-matching Sopro Shade concept of the Sopro 717(®) intraoral camera (assisted visual evaluation method) by comparing it with the Vita 3DMaster(®) shade guide under the True Shade(®) lamp and the Vita Easyshade(®) spectrophotometric method.

Methods: The basic colour of the maxillary right central incisor and canine of 38 participants was determined by three examiners then repeated the next day using the three evaluation methods. Two examiners were experienced clinicians and one was a Sopro intraoral camera engineer. The Vita 3D-Master shade guide was used with all three colour-matching methods. Kendall's tau-b correlation coefficients between the different series of tooth-colour evaluations were computed and two-tailed t-tests for paired samples were applied.

Results: Regardless of the tooth examined, significant intra-examiner agreement (p < 0.05) occurred between the visual and the assisted visual methods. Inter-examiner reliability was higher for canines than for central incisors, for all three methods. When comparing the two visual assessments with the spectrophotometric one, Kendall's tau-b correlation coefficients were lower. When comparing the two visual methods, significant agreement (p < 0.05) was found for both canines and central incisors.

Conclusions: Within the limitations of this study, the Sopro Shade concept of the Sopro 717 intraoral camera is a reliable assistance to visual colour assessment compared with conventional visual methods. The reproducibility and reliability of all methods and examiners' measurements for canines were generally higher than those for central incisors. The possible clinical impact of the lower level of agreement between the two visual methods (conventional and assisted) compared with spectrophotometry should be studied further.