Masking severely discolored dentitions is one of the indications for the use of ceramic veneers. IPS e.max Press and Vita VM7 had significantly higher contrast ratios and masking abilities than Nobel Rondo Press Alumina: Solo. However, none of the materials tested was able to completely mask the black background. SUMMARYStatement of the Problem: Porcelain veneer materials are translucent and are therefore affected by their thickness as well as the color of the underlying substructure, which limits their masking ability and compromises the esthetic result in heavily stained teeth.Purpose: The purpose of this study was to compare the contrast ratio (CR) and masking ability of three different veneering ceramics with two thicknesses by measuring the color differences over white and black backgrounds. Correlations between CR and masking ability of these veneering ceramics were evaluated.Methods and Materials: A total of 30 discshaped specimens (12 mm diameter 3 1.0 mm or 1.5 mm) were fabricated in shade A2 from three types of all-ceramic systems: IPS e.max Press (IPSe; Ivoclar Vivadent, Schaan, Liechtensein), Vita VM7 (VM7; VITA Zahnfabrik, Bad Sä ckingen, Germany), and Nobel Rondo Press Alumina: Solo (NRPA; Nobel Biocare, Zü richFlughafen, Switzerland). The CR, defined as the ratio of illuminance (Y) of the test material when placed on the black background (Yb) to the illuminance of the same material when placed over a white background (Yw), was determined (CR=Yb/Yw). The color (CIE L*a*b*) and Y of each specimen were measured over standard white and black tiles using a spectrophotometer (ColorEye 7000 A, Model C6, GretagMacbeth, New Windsor, NY, USA). Masking abilities of the specimens were determined by measuring the color difference (DE) over white and black backgrounds. Both CR and DE data were analyzed using two-way analysis of variance (ANOVA). One-way AN-OVA was used to compare the mean values of CR across the three materials followed by the Duncan multiple comparison test. The Results: CR values of NRPA were significantly less than those of IPSe and VM7, and the CR of IPSe was higher than that of VM7. Furthermore, CR increased as the thickness of the discs increased to 1.5 mm for all three materials. Mean DE values were significantly higher with 1.0-mm-thick discs than with 1.5-mm discs. Among the three materials it was observed that NRPA had the highest DE when compared with IPSe or VM7, whereas the DE of the latter two were not significantly different from one another. There was a strong linear correlation between CR and masking ability.Conclusion: CR and masking ability are affected by the type as well as the thickness of the ceramic used. IPSe and VM7 are similar in their masking abilities, whereas NRPA had the lowest masking ability. NRPA was the most translucent, followed by VM7; IPSe was the most opaque. None of the materials tested was able to completely mask the black background. It is therefore recommended that the type of ceramic should be chosen according to each clinical situation.

BackgroundInfection is one of the most crucial problems in health care services worldwide. It is considered one of the most important causes of morbidity and mortality associated with clinical, diagnostic and therapeutic procedures. Therefore, the purpose of this study was to investigate knowledge, attitude, and compliance with recommended infection control guidelines among dental faculty members and students at King Saud University, Riyadh, Kingdom of Saudi Arabia.MethodsA cross-sectional study was conducted to obtain information regarding knowledge, attitude, and compliance with recommended infection control guidelines. The sample (n = 317) comprised of dental faculty members and students (3rd, 4th and 5th year) in both male and female campuses of College of Dentistry (KSU).This questionnaire contained three parts (knowledge, attitude, and compliance) and was distributed to the participants. After validation of the survey, data were collected, entered and analyzed by SPSS software.ResultsA total of 317 dental faculty members and students participated in this study. Out of the total study subjects, 141 (44.5%) were female and 176 (55.5%) were male. A comparison between dental faculty members and students was made based on their knowledge, attitude, and compliance, which resulted in almost equal percentages of knowledge (49.6, 49.0% respectively). In addition, it revealed that faculty members’ attitude toward infection control in the dental clinic was more positive compared to their compliance with the infection control guidelines (70.6, 65.2% respectively) while with the students it was vice versa (67.2, 69.6% respectively).There is no statistically significant difference in the knowledge and attitude of dental faculty members and students regarding infection control guidelines (P > 0.05).ConclusionOur study showed that dental undergraduate student and faculty members at KSU demonstrated a good adherence to infection control guidelines. On the other hand, there was a lack in the knowledge of the basics of infection control standards.