Color changes of three different brands of acrylic teeth in removable dentures in three different beverages: An in vitro study.

Background. The best prosthetic appliances exhibit a high level of similarity to the lost organ. Color should exhibit favorable stability, as a critical factor in the esthetic appearance of dental prostheses and materials used in fabricating prostheses. The present in vitro study was undertaken to evaluate color changes of three different brands of acrylic resin teeth in three different beverages. Methods. In this in vitro study, 10 samples from each brand of acrylic resin tooth (Ivoclar, Italy; BStar, Iran; and BetaDent, Iran) were immersed in the following beverages for one week: tea, orange juice, natural carrot juice, and distilled water (control). The color parameters were measured using the spectrophotometry technique before and after immersion, and changes were calculated. The same procedures were carried out with the same number of samples at 30-day interval. Data were analyzed with multivariate ANOVA and post hoc Tukey tests. Results. After seven days, Ivoclar and BStar brands exhibited the minimum (1.78) and maximum (3.39) color changes, respectively (P<0.05). At the 30-day interval, the Ivoclar and BetaDent brands exhibited the minimum (3.03) and maximum (4.27) color changes, respectively (P<0.05). At the 7-day interval, carrot juice, orange juice and tea, in descending order, caused the maximum and minimum color changes. At the 30-day interval, carrot juice resulted in maximum color changes (P<0.05); orange juice, and tea caused similar color changes (P>0.05). Conclusion. Different beverages resulted in color changes with different patterns in different brands of acrylic resin teeth. Overall, the Ivoclar brand exhibited less color changes compared to BStar and BetaDent brands. In the first week, all the three brands and in 30 days, Ivoclar and BStar brands exhibited clinically acceptable color changes.

Association between demographic and radiographic characteristics of the schneiderian membrane and periapical and periodontal diseases using cone-beam computed tomography scanning: A retrospective study.

Background. This study was undertaken to assess the pathological and spatial associations between periapical and periodontal diseases of the maxillary first molars and thickening of maxillary sinus mucosa with cone-beam computed tomography. Methods. A total of 132 CBCT images of subjects 20‒60 years of age were evaluated retrospectively. The patients' sex and age and demographic and pathologic findings of the maxillary sinus in the first molar area were recorded, graded and analyzed. Results. Approximately 59% of patients were male and 41% were female, with no significant difference in the thickness of schneiderian membrane between males and females. Based on the periapical index scoring, the highest frequency was detected in group 1. Based on the results of ANOVA, there were no significant differences in the frequencies of endodontic‒periodontal lesions and an increase in schneiderian membrane thickness. There were significant relationships between periapical and periodontal infections (P<0.001) and schneiderian membrane thickness. Furthermore, a significant relationship was detected between the thickness of the schneiderian membrane and the distance between the sinus floor and the root apices (P=0.38). Conclusion. A retrospective inspection of CBCT imaging revealed that periapical lesions and periodontal infections in the posterior area of the maxilla were associated with thickening of the schneiderian membrane. In addition, there was a significant relationship between the location of maxillary posterior teeth, i.e. the thickness of bone from the root apex to the maxillary sinus floor, and schneiderian membrane thickness.