Radiopacity evaluation of different types of resin restorative materials using a digital radiography system.

OBJECTIVES: The aim of the study was to evaluate and compare the radiopacity of 20 current dental resin composites with digital radiography. METHODS: Ten specimens, 10-mm in diameter and 1-mm thickness, were prepared and radiographed using phosphor plates close to Al step wedges and tooth sections. The mean grey values (MGVs) were measured using an ImageJ software program and converted to equivalent Al thickness. Data were analyzed using one-way analysis of variance (ANOVA) and Tamhane post hoc test (p < 0.05). Correlation between mean radiopacity and filler content (wt% and vol%) of the tested materials was analyzed with linear regression analysis. RESULTS: The radiopacity of all composites ranged from 1.32 mm Al (Estellite Flow Quick) to 3.41 mm Al (Charisma Classic). All the tested materials, except four restorative materials, had a radiopacity equal or higher than the enamel (p < 0.05). Linear regression revealed low correlation between the radiopacity and filler content of the composite. CONCLUSION: Majority of the materials has appropriate radiopacity for dental restorations. There was great variation in radiopacity level, may clinically affect the diagnosis.

The Effect of Gastric Acid on the Surface Properties of Different Universal Composites: A SEM Study.

The aim of this study is to compare surface roughness and microhardness changes of three monochromatic (Omnichroma, Vittra Unique, and Charisma Diamond One) and three universal shade (Neo Spectra ST, G-ænial A'CHORD, and Nova Compo C) resin composites after exposure to simulated gastric acid. A total of 144 disc-shaped specimens (24 discs of each composite resin) were prepared using plexiglass molds (R = 5 mm × h = 2 mm) for evaluation from each material. Specimens of each material were divided into two main groups for the evaluation of the microhardness and surface roughness and also two subgroups for 7- and 14-day exposures to simulated gastric acid. Initial microhardness and surface roughness measurements of all samples were measured before immersion (T1) followed by exposing the samples to simulated gastric acid for 7 days (T2) and 14 days (T3), and then, the microhardness and roughness measurements were repeated. Randomly selected specimens of each material for each of the time intervals (T1, T2, and T3) were evaluated with scanning electron microscopy (SEM). One-way ANOVA revealed that the surface roughness and hardness values of all tested composite resin restorative materials show no statistically significant difference for the initial (T1) value (p > 0.05). Regarding the 7th day (T2) and 14th day (T3) surface roughness and microhardness value of all composites, there are statistically significant differences between the groups (p < 0.05), while there was no statistically significant difference between the surface hardness reduction percentage between the time intervals (p > 0.05). As a result of this in vitro study, increase in surface roughness and decrease in microhardness of the tested universal composite materials when exposed to simulated gastric acid were statistically significant.

Effects of storage time and restoration depth on instrumental color adjustment potential of universal resin composites.

PURPOSE: To determine the instrumental color adjustment potential (CAP-I)of 3 universal composites at 2 time intervals and 2 depths. METHODS: Omnichroma, Estelite Sigma Quick, and Filtek Universal Restorative were tested. Two types of specimens were prepared. For dual specimens, Class V restorations were created in anterior denture teeth and restored with resin composites. For single specimens, replications were fabricated with resin composites (n = 10). Unrestored teeth were used for comparison. Color was measured with a spectrophotometer at 24 h and 1 month, and CAP-I was calculated. Data were compared by analysis of variance followed by the Student t-test and paired sample t-test. RESULTS: The CAP-I of tested materials ranged from 0.11 to 0.27 at 24 h and from 0.60 to 0.76 at 1 month. At 24 h, Omnichroma yielded the highest values, followed by Estelite Sigma Quick and Filtek Universal Restorative (P < 0.05). CAP-I was significantly higher at 1 month than at 24 h in all groups. In all groups, restorations with a depth of 3.0 mm yielded better results than restorations with a depth of 2.0 mm (P < 0.05). CONCLUSION: Storage time and restoration depth were positively associated with CAP-I. Single-shade and multi-shade universal composites are good alternatives for color-matched, esthetically satisfying restorations.