Influence of background/surrounding area on accuracy of visual color matching.

INTRODUCTION: Visual shade selection is subjective and influenced by factors that might be operator-dependent or not. The objective was to evaluate influence of observer nonrelated factors (background/surrounding area, and light) and observer-related factors (gender and color competence) on shade-matching quality and to identify the most often mismatched shades in correlation with the background. METHODS: Ten observers with average or superior color discrimination competence according to ISO TR 28642:2011 were asked to match 48 shade tabs of three VITA Classical shade guides, in a viewing booth under two light sources: D65 and D50. Gray, white, black, red, and light blue background/surrounding area simulated various clinical situations. The results were statistically analyzed using Kruskal-Wallis test and Mann-Whitney U test. Post hoc power analyses and sample size calculations were also conducted. RESULTS: The matching scores ranged between 72.7 % (using blue background) and 85.9 % (using white and black backgrounds). There was a statistically significant difference between matching scores on the five backgrounds (χ (2)(4) = 12.67, p = 0.01). When neutral gray was used as reference, Mann-Whitney U value was statistically significant only for the blue background (U = 107.00, Z = -2.52, p = 0.01). The influence of gender and lighting condition was also assessed, no statistically significance being found, but in both cases, the effect size and the achieved power were small. However, color discrimination competence did influence the results (p < 0.01). Background influenced shade matching results for tabs A3, B3, B4, and D4. CONCLUSIONS: Within the limitations of this study, it was concluded that 1. When it comes to the influence of the background/surround area on quality of color matching, no difference among achromatic backgrounds was recorded. Significantly worse results were recorded when the blue background was used. 2. Observers with superior color matching competence performed significantly better than the ones with average competence 3. The most frequently mismatched shade tabs were A3.5, B3, B4, and D4.

The contribution of computerized axiography to the functional evaluation of the temporomandibular joint: a case report.

The aim of this case report is to give comprehensive information on the clinical use of computerized axiography (CA) in the evaluation of temporomandibular joint (TMJ) mobility in a patient who undergoes orthognatic surgery. A 20-year-old female patient with class III skeletal anomaly and who underwent orthognatic surgery is presented. Pre- and postsurgical CA recordings for the patient are compared in order to evaluate the functional modifications that appear. The CA is a functional investigation of the TMJ and records the border movements of the mandible: protrusion, lateral movements and open/close. The starting point for every movement is the centric relation position. This allows for very high reproducibility of the CA and the data can later become available for comparison of examinations performed at different times. The CA can offer data to programme an articulator or to evaluate the functional evolution of the TMJs after various occlusal interventions (prosthodontic, orthodontic or orthognatic). After comparing the pre- and postsurgical CA recordings, a significant improvement of the TMJ function after the repositioning of the maxilla and mandible through orthognatic surgery was confirmed. In conclusion, our case confirms the results in literature that CA is a reproducible and reliable investigation method in the evaluation of TMJ function in orthognatic surgery patients, that it facilitates the monitoring of the evolution of the functionality of the TMJ ever time and that it allows for comparative evaluation of the two TMJs.