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The predoctoral dental curriculum includes didactic lectures, demonstrations, and training on shade-matching techniques and protocols. However, a significant percentage of esthetic failures are still observed clinically. An assessment is required to determine whether reevaluation and modification of this training protocol would help future dental practitioners better perceive and communicate the dental shade.The purpose of this study was to evaluate dental students' knowledge of and skill in shade selection and effective prescription writing before and after educational training with 3 different shade guides.Thirty predoctoral dental students (interns) who had completed their academic program and were undergoing clinical training were selected. After excluding color vision deficiency, the study participants were first asked to evaluate the shade of the right maxillary central incisor of 5 patient participants by using 3 different shade guides (Vitapan Classical, Vitapan 3D-MASTER, Chromascop) under standardized conditions. They were then asked to write an esthetic prescription, communicating the shade to a dental laboratory technician. A dental faculty member evaluated the baseline control shade for each participant, and a standardized prescription format was written. This was used as a reference by a dental laboratory technician to score the intern's prescription as clear, unclear, poor, or illegible. After the assessment, focused small group learning with lectures, clinical demonstrations, and case-based discussion was provided to the interns on shade assessment over 10 to 15 days. All the interns were reassessed for their visual shade perception and prescription writing after a month's interval. The mean percentage agreement, mean percentage shade match, and mean color difference between the shade selected and the control shade for each of the 5 participants, with all 3 shade guides, were evaluated along with the prescription scoring before and after the educational training. Statistical comparison of before and after values were made by using the paired-sample z-test for percentage agreement versus disagreement among the interns for the shade selected, paired t test for mean percentage agreement, mean percentage shade match, and mean color difference. The repeated measure ANOVA test was used for the prescription scorings (α=.05).A significant difference in prescription scoring (P.001) was observed. A significant difference in the percentage shade match (P.01) for all 3 shade guides and mean percentage agreement for Chromascop and Vita 3D-MASTER (P.05) were observed. A nonsignificant mean color difference between the shade selected by the intern and the baseline shade was observed.A significant difference in prescription scoring was observed after training, along with a higher percentage shade match and percentage agreement. This indicated a need to reconsider the educational training provided for dental shade assessment and communication and to implement better protocols in the dental curriculum.

There is evidence to suggest that liver tumor promoters exert their effect through the interference of signal transduction in hepatic cells. Both phospholipase A(2) and phospholipase C play important roles in the generation of second messengers and in the activation of Ca(2+), phospholipid-dependent protein kinase C. Using male Sprague-Dawley rats, we investigated whether liver tumor-promoting regimens of a choline-deficient diet and phenobarbital alter the activities of phospholipase A(2) and phospholipase C in the liver, and extended the study to determine the effect of a choline-deficient diet on protein kinase C activities. Feeding a choline-deficient diet for 1 week increased the activities of both phospholipase A(2) (50%) and phospholipase C (22%), and the activities of both enzymes were more than doubled after 4 weeks. Feeding a phenobarbital diet resulted in a slight decrease in phospholipase A(2) activities at 4 weeks but no significant changes in PLC activities. The protein kinase C activities and its distribution between soluble and particulate fractions remained unchanged after 1, 2, and 4 weeks feeding of a choline-deficient diet. Thus, activation of both phospholipase A(2) and C is distinct for a choline-deficient diet, not shared by phenobarbital diet. Increased activities of these enzymes were not associated with the activation of protein kinase C under the present experimental condition.