Kivanc Yamanel

Micro push-out bond strengths of 2 fiber post types luted using different adhesive strategies

OBJECTIVE The objective of this study was to evaluate the push-out bond strengths of carbon and glass fiber posts adhesively luted with Panavia F 2.0 and RelyX Unicem luting cements, as well as a modified application procedure using RelyX Unicem cement in combination with a single-bottle total-etch adhesive in 3 segments of teeth. STUDY DESIGN Sixty single-rooted human maxillary central incisors and canines were sectioned below the cementoenamel junction, and the roots were endodontically treated. The roots were divided into 2 fiber-post groups, and then divided into 3 subgroups of 10 specimens each to test different luting strategies. Bonded specimens were cut (1-mm-thick sections) and push-out tests were performed (crosshead-speed, 0.5 mm/min). Failure modes were evaluated using a stereomicroscope at original magnification ×40. RESULTS Micro push-out bond strengths were significantly affected by the type of luting agent and the type of post (P < .05). In all root sections, the push-out bond strength values of glass fiber posts were significantly higher than that of carbon fiber posts (P < .05). Moreover, the highest push-out bond strengths were measured for Panavia F 2.0 and RelyX Unicem cements. These values were significantly higher than that of modified application procedure in the medium section for both glass- and carbon-fiber posts, and in the apical root sections only for glass-fiber post (P < .05). In each region, the modified application procedure showed the lowest bond strength values. Adhesive failure between dentin and cement was the most frequent type of failure. CONCLUSIONS In all root segments, the glass fiber post provided significantly increased post retention compared with the carbon fiber post, regardless of the luting strategy used.

Assessment of Color Parameters of Composite Resin Shade Guides Using Digital Imaging versus Colorimeter

PURPOSE This study evaluated the color parameters of resin composite shade guides determined using a colorimeter and digital imaging method. MATERIALS AND METHODS Four composite shade guides, namely: two nanohybrid (Grandio [Voco GmbH, Cuxhaven, Germany]; Premise [KerrHawe SA, Bioggio, Switzerland]) and two hybrid (Charisma [Heraeus Kulzer, GmbH & Co. KG, Hanau, Germany]; Filtek Z250 [3M ESPE, Seefeld, Germany]) were evaluated. Ten shade tabs were selected (A1, A2, A3, A3,5, A4, B1, B2, B3, C2, C3) from each shade guide. CIE Lab values were obtained using digital imaging and a colorimeter (ShadeEye NCC Dental Chroma Meter, Shofu Inc., Kyoto, Japan). The data were analyzed using two-way analysis of variance and Bonferroni post hoc test. RESULTS Overall, the mean ΔE values from different composite pairs demonstrated statistically significant differences when evaluated with the colorimeter (p < 0.001) but there was no significant difference with the digital imaging method (p = 0.099). With both measurement methods in total, 80% of the shade guide pairs from different composites (97/120) showed color differences greater than 3.7 (moderately perceptible mismatch), and 49% (59/120) had obvious mismatch (ΔE > 6.8). For all shade pairs evaluated, the most significant shade mismatches were obtained between Grandio-Filtek Z250 (p = 0.021) and Filtek Z250-Premise (p = 0.01) regarding ΔE mean values, whereas the best shade match was between Grandio-Charisma (p = 0.255) regardless of the measurement method. CONCLUSION The best color match (mean ΔE values) was recorded for A1, A2, and A3 shade pairs in both methods. When proper object-camera distance, digital camera settings, and suitable illumination conditions are provided, digital imaging method could be used in the assessment of color parameters. Interchanging use of shade guides from different composite systems should be avoided during color selection.

Effect of sodium ascorbate on bond strength of different adhesive systems to NaOCl-treated dentin

The aim of this study was to evaluate the effects of sodium ascorbate on bond strength of different adhesive systems to NaOCl-treated dentin. Eighty extracted molar teeth were used in the study. The buccal enamel surfaces were removed to obtain a flat dentin surface. The teeth were mounted in self-curing resin and dentin surfaces were irrigated with NaOCl for 10 min. Half of the specimens were treated with sodium ascorbate for 10 min. The teeth were randomly assigned to four subgroups according to the adhesive systems used (Clearfil SE Bond, Clearfil Tri-S Bond, Adper Prompt-L-Pop, Adper Single Bond 2). Bond strengths were determined with a Universal Testing Machine, at a crosshead speed of 0.5 mm/min. Data were statistically analysed using anova at a significance level of 0.05. Two-way ANOVA revealed that the effect of sodium ascorbate application on bond strength of adhesive systems to NaOCl-treated dentin was statistically significant (P < 0.05). The bond strength results were significantly influenced by the application of sodium ascorbate (P < 0.05) and there was a significant difference between the adhesive systems (P < 0.05). Although statistically significant differences were not demonstrated in all adhesive resin groups, sodium ascorbate application after NaOCl treatment improved the bond strength values.

Clinical Evaluation of Resin-Based Composites in Posterior Restorations: A 3-Year Study

Objectives: The aim of this study was to evaluate the clinical performance of a nanohybrid and a microhybrid composite in class I and II restorations after 3 years. Subjects and Methods: A total of 82 class I and class II restorations were performed in 31 patients (10 males and 21 females) using Grandio and QuiXfil with self-etch adhesives (Futurabond and Xeno III). The restorations were clinically evaluated by 2 operators 1 week after placement (baseline) and at 6 months and 1, 2, and 3 years using modified United States Public Health Service (USPHS) criteria. At the 3-year follow-up, 62 class I and class II cavities were reevaluated in 23 patients (7 males and 16 females). Statistical analysis was performed using Pearsons χ2 and Fishers exact tests (p < 0.05). Results: At the 6-month follow-up, all restorations received Alfa scores with respect to each evaluation criterion. At the 1-year follow-up, 2 QuiXfil restorations had to be replaced and Grandio restorations started to deteriorate in terms of marginal adaptation. At the end of 2 years, 9 Grandio restorations showed significant deterioration of the surface properties, demonstrating Bravo scores. At the end of 3 years, no significant differences were observed regarding color match, marginal adaptation, secondary caries, marginal discoloration, and anatomic form loss between the evaluated materials in 25 class I and 37 class II restorations. At the 3-year follow-up, Grandio restorations had 21% Bravo scores and showed significant deterioration of the surface properties, which were still clinically acceptable according to USPHS criteria. Three QuiXfil and 1 Grandio restorations were replaced because of secondary caries and loss of retention. Conclusions: Both the nanohybrid (Grandio) and the microhybrid (QuiXfil) composites were clinically functional after 3 years.

Effects of staining and bleaching on a nanohybrid composite with or without surface sealant

Objective: The effect of different staining solutions and a bleaching procedure on color stability and surface roughness of a nanohybrid resin composite were evaluated with or without liquid resin polishing (RP). Materials and Methods: Ninety-six disc-shaped resin composite specimens (A1 Shade, Z550 Filtek 3M ESPE, St. Paul, MN, USA) were prepared and divided randomly into two groups (n = 48). Liquid RP (BisCover LV, Bisco Inc., Schaumburg, IL, USA) was applied in one group (RP) and not in the other (P). Specimen color and surface roughness were determined using a colorimeter and profilometer, respectively. After baseline measurements, each group was divided into four subgroups (n = 12) for immersion in a control (distilled water) or three different staining solutions (ice tea, red wine, and cola) for 1 week. Color and surface roughness were then reevaluated. After measurements, all specimens were bleached using a 35% hydrogen peroxide gel. The color and surface roughness of the specimens were reevaluated. Statistical Analysis: Data were subjected to an analysis of variance for repeated measurements among the groups (P < 0.05). Results: Staining and bleaching did not change the surface roughness of the RP and P groups (P > 0.05). Discoloration in the red wine group was higher than for the other staining solutions for the RP (P < 0.001) and P groups (P = 0.018). Conclusion: Application of liquid RP did not enhance the color stability and surface roughness of the composite resin restoration.

Clinical evaluation of microhybrid composites in noncarious cervical lesions: 24-month results

Objective: To evaluate the clinical performance of two different microhybrid resin composites in noncarious cervical lesions (NCCLs) after 24 months. Subjects and Methods: Ninety-seven NCCLs were restored with either TPH Spectrum (n = 48) or Filtek Z250 (n = 49) using an etch-and-rinse adhesive in 20 patients. The restorations were clinically evaluated using modified United States Public Health Service criteria for retention, color match, marginal discoloration, marginal adaptation, surface texture, anatomic form, postoperative sensitivity, and secondary caries. The restorations were assessed 1 week after placement (baseline) and after 6, 12, and 24 months. Restoration survival rates were calculated using the Kaplan–Meier procedure estimator, and a log-rank test was used to compare the survival distributions (P < 0.05). Statistical analysis was undertaken using Pearsons Chi-square test and Fishers exact test to assess differences among the restorative materials (P < 0.05). Cochrans Q-test was employed for evaluating differences in the same restorative material between recall periods. Results: The retention rates were 100% at 6 months, 89.6% and 91.8% at 12 months, and 85.4% and 89.8% at 24 months for TPH and Z250, respectively. TPH showed a statistically significant difference in marginal discoloration between the baseline and 24 months results (P < 0.05). Both TPH and Z250 showed statistically significant differences in marginal adaptation between the baseline and 24 months results (P < 0.05). Conclusion: Over the 24-month period, both microhybrid resin composites demonstrated acceptable clinical results in NCCLs.