Effect of Different Adhesive Resin and Composite Veneering Materials on Adhesion to Polyetheretherketone.

OBJECTIVE: To evaluate the effect of different adhesives and veneering resins on the shear bond strength (SBS) of polyetheretherketone (PEEK). METHODS: A total of 138 PEEK specimens were randomly divided into 6 groups according to adhesive material application: Control (C, no application), Adhese Universal (A) (Ivoclar Vivadent, Schaan, Liechtenstein), Gluma Bond Universal (G) (Heraeus Kulzer, South Bend, IN, USA), G-PremioBOND (P) (GC Corporation, Tokyo, Japan), Single Bond Universal (S) (3M, Saint Paul, MN, USA) and visio.link (V) (Bredent, Senden, Germany). Each adhesive group was divided into two subgroups according to the type of veneering material: Estenia direct composite (D) and Gradia Plus indirect composite (IN) (both GC Corporation). After the veneering process, the specimens were aged by thermal cycling. Kruskal-Wallis and Mann-Whitney U tests were used for SBS analysis (P < 0.05). RESULTS: The highest SBS results were obtained in the VIN group, followed by the VD, PD, GIN, AIN, AD, SIN, SD, PIN, GD, CIN and CD groups, respectively (P = 0.001). There were no significant differences in terms of the type of veneering composite when the same adhesive was applied (P > 0.05), except for Gluma Bond Universal (P = 0.009). All the adhesives tested showed clinically acceptable SBS results. CONCLUSION: Visio.link offered the highest adhesion to PEEK, whereas the tested universal adhesives may be used as an alternative to visio.link in clinical settings. It was determined that changing the veneer type has no statistical difference when the same adhesive material is used.

Effects of polishing protocols on the surface roughness and color stability of polyetheretherketone (PEEK).

Purpose: This study aimed to evaluate the effects of different polishing protocols on the surface properties and color stability of the polyetheretherketone (PEEK). Materials and methods: A total of 96 disc-shaped specimens were fabricated from PEEK material and divided into 6 different groups: control (CN), ''Abraso-Starglanz'' polishing paste (A), ''Yildiz'' polishing paste (Y), ''Enhance'' polishing system (EN), ''Super snap'' polishing kit (SS), and silicone polisher (SP). Surface roughness (Ra) were measured with a profilometer and the surface topography was examined under scanning electron microscope. Color differences were measured with a spectrophotometer according to the CIEDE2000 (∆E00) formulation before and after coffee immersion. Data were statistically analyzed with Kruskall-Wallis and Spearman's correlation analysis (p<0.05, p<0.001). Results: A statistically significant difference was observed between the Ra measurements of the polishing protocols (p<0.001). Ra measurements except A, Y, and SS groups were found to be higher than the clinical acceptable threshold of surface roughness (0.20 µm). In ΔE00 measurements, statistically significant differences were observed between the CN and SP (p=0.041), EN (p=0.001), and A (p=0.002) polishing protocols. No correlation was found between Ra and color stability. Conclusion: Only in the A, Y and SS polishing protocols, Ra measurements were not found to be risky in terms of acceptable threshold of surface roughness. Polishing protocols have also generally failed to maintain the color stability. Considering the surface roughness and color stability, the ''Abraso-Starglanz'' paste may be suitable method for PEEK material.

Ion release from metal-ceramic alloys in three different media.

The aim of this in vitro study was to assess the effect of pH changes on ion release of metal-ceramic dental casting alloys. Samples from four commercially available alloys (Wirobond C, Wiron 99, Rematitan CP-Ti grade 1, and PontoStar) were prepared and polished. Ion release of alloys subjected to three different pH media (artificial saliva of pH 2.3, pH 6.5 and 0.9% saline solution of pH 7.3) for periods of 7, 15, 30, and 60 days were assessed by means of atomic absorption spectroscopy. Microscopic changes on surfaces of metallic samples before and after immersion were compared by scanning electron microscopy. ANOVA was used for statistical analysis of results. For all ions, pH and period interactions were statistically significant: highest amount of ion release occurred after 60 days of immersion regardless of pH value. For every alloy, ion release results were highest in artificial saliva of pH 2.3 and lowest in 0.9% saline solution. It was concluded that ion release from alloys was pH-dependent.

In vitro color stability of provisional crown and bridge restoration materials.

Discoloration of provisional restorations can be an esthetic problem, especially when the treatment plan requires long-term provisionalization. In this study, therefore, we examined the effects of staining solution on the color stability of these provisional crown and bridge restoration materials: Structur, Temdent, and Tab 2000. Treatment solutions were namely carrot juice, tea, cola, light cola, and distilled water. Thirty samples were prepared for each type of provisional material, such that a total of 90 samples were prepared. The color value of each sample was measured with a colorimeter at baseline and after one day, one week, two weeks, and four weeks of immersion in various treatment solutions. Results were determined using the CIELAB system. Color change data were calculated and subjected to two-way analysis of variance. To examine significant interactions, one-way ANOVA and Tukey's multiple comparisons test were performed to identify differences between the solutions (p < or = 0.05). After four weeks of treatment, color difference values were found to range from 0.20 to 3.99 deltaE* units. The highest color difference values were obtained in carrot juice, cola, and tea with Structur samples after four weeks, where these values were categorized as "noticeable" and "unacceptable" color change values. Based on the results of this study, we do not recommend amine-containing Structur to be used as a provisional crown and bridge restorative material for treatments of a longer duration.

Color stability of a dental composite after immersion in various media.

The purpose of this study was to determine the effects of staining solutions on the different shades of a dental composite, and to compare these effects with that of distilled water. Two shades of effect (ET1 and ET2), two shades of enamel (EL and EM), and two shades of dentin (DA1 and DA2) were used. Specimens were immersed in three staining solutions (chlorhexidine gluconate, filtered coffee, and orange juice) and distilled water. Color changes were characterized using the CIELAB color space. Since significant interactions occurred, the staining effect of each solution on each shade was determined using one-way ANOVA and the levels of factor in one-way ANOVA were compared using Tukey's method (p < or = 0.05). The staining solutions were found to be more chromogenic than distilled water, and EM and DA2 shades were found to be more color-stable. Based on the color change results in this study, chlorhexidine gluconate (1.45), filtered coffee (1.43), and orange juice (1.02) were determined as having "slight" staining effects on the tested shades. As for the tested shades in this study, they revealed acceptable color change results.