Extrinsic Stain Assessment Using a Stain Shade Guide

Assessment of extrinsic dental stain by the recognised Lobene Stain Index can be very subjective, particularly in determining stain intensity. Objectives: For the present study these were:(1) to produce a stain shade guide to aid the in vitro & in vivo assessment of extrinsic dental stain (2) to assess in vivo intra and inter examiner reproducibility of measuring extrinsic stain using the stain guide. Methods: Triplicate batches of acrylic teeth and clear perspex specimens were stained following multiple exposures to saliva, chlorhexidine and tea. The optical densities of stain on the perspex specimens were measured using a UV/visible light spectrophotometer and the mean values assigned to the corresponding stained acrylic teeth. These were subsequently made into a stain shade guide. Two examiners on 2 occasions used the stain guide to assess extrinsic stain on the anterior teeth of 10 volunteers. For comparison, stain was also assessed using the Lobene Stain Index. Intra and inter examiner reproducibility was determined using kappa statistics. Results: Using the stain guide improved intra examiner reproducibility of stain intensity (Examiner 1, k = 0.89, Examiner 2, k = 0.87) compared to using the Lobene Index (Examiner 1, k = 0.61, Examiner 2, k = 0.80). Similarly, inter examiner reproducibility was improved (stain guide, k = 0.73, Lobene Index, k = 0.55). Conclusions: The findings of this study would suggest that the use of the stain guide may help to improve reproducibility in the clinical assessment of extrinsic stain.