Effect of surface roughness and biofilm formation on the color properties of resin-infiltrated ceramic and lithium disilicate glass-ceramic CAD-CAM materials.

STATEMENT OF PROBLEM: Computer-aided design and computer-aided manufacturing (CAD-CAM) materials have become popular for dental restorations; however, which materials should be preferred in terms of surface properties after biofilm formation is unclear. PURPOSE: The purpose of this in vitro study was to investigate the effect of biofilm formation on the discoloration properties of resin-infiltrated ceramic and glass ceramic CAD-CAM materials and human teeth and to examine the effect of the brushing procedure on color change. MATERIAL AND METHODS: One hundred and six 2-mm-thick specimens were prepared from IPS e.max CAD and Cerasmart, and a total of 53 intact human teeth were used. Five specimens from each group were used to measure the amount of live biomass in the biofilm. The remaining 48 specimens in each group were divided into 4 subgroups: kept in distilled water without the formation of dental biofilm (DW), kept in tea without the formation of dental biofilm (T), kept in distilled water after the formation of dental biofilm (DWB), and kept in tea after the formation of dental biofilm (TB) (n=12). After finishing and polishing the materials, initial color measurements were made using a spectrophotometer, and surface roughness measurements were made using noncontact profilometer. After creating a biofilm layer in DWB and TB, all specimens were kept in their solutions at 37 °C for 24 hours, and the color measurements were repeated. After the biofilm layer had been removed by brushing, a third color measurement was made. The data were statistically analyzed with one-way analysis of variance (ANOVA) and two-way ANOVA (α=.05). RESULTS: The lowest roughness value was observed in Cerasmart. Tooth-IPS e.max CAD gave similar results. The Cerasmart material had the most viable biomass, whereas the IPS e.max CAD material had the least. TB had the highest ΔE1 value for all materials and DW had the lowest (P<.05). The brushing procedure caused the materials to return to their initial colors or reduce the color change in most groups. CONCLUSIONS: The presence of biofilm on CAD-CAM materials immersed in distilled water caused an unacceptable degree of discoloration (ΔE>1.8), and immersion in tea led to greater color change. The adhesion of biofilm to restorative dental materials plays an important role in the coloring of these dental materials.

Wear behavior of different materials used for pit and fissure sealing.

PURPOSE: To evaluate the wear of different materials used for pit and fissure sealing applied with non-invasive and invasive preparation techniques. METHODS: A total of 170 molar teeth were divided into two main preparation groups (non-invasive and invasive), each consisting of eight subgroups after a control group was separated for wear standardization. Eight subgroups included: nano-filled flowable composite (Filtek Ultimate Flow), nanohybrid flowable composite (GrandioSo Flow), micro-hybrid flowable composite (Majesty Flow), resin-based unfilled fissure sealant (ClinPro Sealant), resin-based filled fissure sealant (Fissurit FX), resin-based highly filled fissure sealant (GrandioSeal), giomer-based fissure sealant (BeautiSealant), and glass-ionomer-based fissure sealant (Fuji Triage) (n= 10). The materials were applied according to the manufacturers' instructions. The initial data were obtained for wear analysis. The specimens were subjected to 2-year thermocycling and brushing simulations. Final data were obtained, and the wear characteristics were evaluated digitally. Data were statistically analyzed (P< 0.05). RESULTS: There were no significant differences in wear between the non-invasive and invasive application groups (P< 0.05). In comparison of the materials, flowable composites presented the lowest wear (0.15 P± 0.13), and glass-ionomer-based fissure sealant presented the highest wear (0.66 P± 0.32). CLINICAL SIGNIFICANCE: The present study reported that the invasive preparation technique, which slightly abrades the enamel surfaces, did not adversely affect the wear of the sealant materials. Although the application of flowable composites as fissure sealants with a bonding agent is time-consuming and costly, it yielded better results in terms of wear.

The radiographic evaluation of 11 different resin composites.

Radiopacities of dental materials used in restorations are very important in making the radiographic diagnosis. Therefore, the aim of our study was to evaluate the radiopacity of five single-shade and six simplishade resin composites with digital technique. Five different single-shade (Charisma Topaz One, Omnichroma, Clearfil Majesty ES-2 Universal, Vittra APS Unique, ZenChroma) and six different simplishade resin composites (G-aenial A'CHORD, Essentia Universal, OptiShade, Estelite Asteria, Filtek Universal, Filtek Z250) were used. For each group, five disk-shaped resin composites of 1 mm and 2 mm thicknesses were prepared. As a control, tooth slices with 1 mm and 2 mm thicknesses and a 99.5% pure aluminum step-wedge were used. The samples, tooth slices, and a step-wedge were placed on a photostimulable phosphor plate. Digital radiographs were taken from 30 and 40 cm distances (70 kVp, 7 mA 0.28 ms). The images were analyzed using ImageJ software to measure the mean gray values. Data were analyzed using SPSS 22 package program and Kruskal-Wallis H Test (p < 0.05). The highest radiopacity was seen in Filtek Universal at both distances and thicknesses. Omnichroma had the lowest radiopacity in all parameters. All specimens showed higher radiopacity than dentin. Except for Omnichroma 1 and 2 mm thick, Clearfil Majesty ES-2 Universal 2 mm thick, samples showed higher radiopacities than enamel (p < 0.05). The restorative materials tested were found to be more radiopaque than dentin. The samples passed the International Organization for Standardization for radiopacity values. The radiopacity values were affected by thickness and type of materials.

Evaluation of the color stability of attachments made with different resin composites.

INTRODUCTION: Coloring solutions-such as coffee and cola, frequently consumed daily-cause coloration of attachments made with resin composites. This may reduce the motivation for clear aligner treatment, often preferred by patients with esthetic concerns. This study aimed to compare color changes of orthodontic attachments made with 3 different composite resins. METHODS: A total of 90 premolar teeth (n = 10) extracted for orthodontic reasons were used. All teeth were embedded in plaster models to imitate the arch shape and scanned with an intraoral scanner. Horizontal rectangular attachments were placed on each tooth by printing the attachment template obtained using digital models. Three composite resins: Omnichroma, GC Aligner Connect, and Tetric PowerFlow were used to prepare the attachments. The models prepared in arc-shaped in each composite group were divided into subgroups and kept in 3 different solutions (coffee, cola, and distilled water) in the incubator at 37 ± 1°C. The models were photographed at baseline and 28 days later with the Smile-Lite MDP device. L, a, and b values were obtained with Digital Color Meter (version 5.22; Apple, Cupertino, Calif). CIEDE2000 formula (ΔE00) was used to evaluate color changes. In addition, models were scanned for color determination at baseline and 28 days later with the 3Shape intraoral scanner. RESULTS: There were significant color differences between solutions (P <0.05). CONCLUSIONS: Attachments can be colored easily. Patients should be warned against coloring solutions at the beginning of the treatment, and their eating and drinking habits should be regulated.