Anti-Inflammatory Effect of Dental Pulpa Mesenchymal Stem Cell Exosomes Loaded Mucoadhesive Hydrogel on Mice with Dental Nickel Hypersensitivity.

In this study, the anti-inflammatory effect of dental pulp mesenchymal stem cell (MSCs) exosomes loaded to mucoadhesive hydrogel is investigated in a dental nickel hypersensitivity murine model. After culture of dental pulp MSCs in the third passage MSCs are loaded to a mucoadhesive hydrogel based on chitosan, cross-linked with genipin and modified with catechol groups. A dental nickel hypersensitivity model is created by administering NiCl2 and 10 µg mL-1 lipopolysaccharide to 4-6 week-old Balb-c mice by intradermal injection. In mice treated with dental pulp MSC exosomes and exosomes in hydrogel, interferron gamma (IFN-γ) secreting CD4+T lymphocyte ratios significantly increase compared to the untreated group (p < 0.05). IFN-γ and interleukin 10 (IL-10) expression in buccal mucosa tissue sections and IFN-γ secreting CD4+T lymphocyte ratios are found to be significantly higher in mice treated with dental pulpa MSCs (DPMSCs) exosomes and DPMSCs exosomes in hydrogel compared to the untreated group (p < 0.05). According to flow cytometry results, IL-4 secreting CD4+T lymphocytes are found to be significantly decreased in DPMSCs exosomes group compared to dental nickel hypersensitivity group (p < 0.05). Administration of DPMSCs exosomes with mucoadhesive hydrogel may be an alternative to current medication in the treatment of dental nickel hypersensitivity.

Synovial fluid niche promoted differentiation of dental follicle mesenchymal stem cells toward chondrogenesis in rheumatoid arthritis.

Objectives: In this study, we aimed to investigate the differentiation potential of dental follicle mesenchymal stem cells (MSCs) in the synovial fluid (SF) niche of early-onset or end-stage rheumatoid arthritis (RA). Patients and methods: Between May 2020 and January 2021, six patients (1 male, 5 females; mean age: 57.5±11.2 years; range, 49 to 65 years) who were diagnosed with RA with the indication of SF aspiration were included in the study. The third passage dental follicle stem cells (DFSCs) were cocultured with fresh SF samples of end-stage or early-onset RA patients in micromass culture system for 21 days. SF samples were analyzed for secreted cytokines. Chondrogenic markers (CD49e, CD49f) were analyzed in DFSCs, gene expression analysis was performed for the expressions of Col I, Col II, Aggrecan and Sox-9, and histochemical analysis was performed by staining three-dimensional pellets with anti-collagen II antibody. The neutralization assay was performed with anti-interleukin (IL)-6, anti-interferon-gamma (IFN-g), and anti-IL-1beta(b). Results: The high levels of IL-1b and IL-6 were observed in end-stage RA patients' SF samples compared to the early-onset patients (p<0.05). The CD49e and CD49f expressions in DFSCs were significantly higher in the SF samples of end-stage RA patients (p<0.05). Also, the Col II, Sox-9 and Aggrecan messenger ribonucleic acid (mRNA) expressions increased in the DFSCs, when cultured with end-stage RA patients' SF samples (p<0.01). Collagen-II expression in histochemical analysis of micromass pellets was higher in the DFSCs cultured with end-stage RA patients' SF samples. The neutralization of IL-6 significantly decreased the CD49e and CD49f expressions (p<0.05). Conclusion: The high levels of IL-6 in SF niche of end-stage RA patients were found to differentiate DFSCs toward chondrogenesis. Based on these findings, DFSCs can be used as a new cell-based treatment in RA patients for the cartilage damage.

Dental follicle mesenchymal stem cells ameliorated glandular dysfunction in Sjögren's syndrome murine model.

OBJECTIVE: Dental mesenchymal stem cells (MSCs) are potential for use in tissue regeneration in inflammatory diseases due to their rapid proliferating, multilineage differentiation, and strong anti-inflammatory features. In the present study, immunoregulatory and glandular tissue regeneration effects of the dental follicle (DF)MSCs in Sjögren's Syndrome (SS) were investigated. METHODS: Dental follicle (DF) tissues were obtained from healthy individuals during tooth extraction, tissues were digested enzymatically and DFMSCs were cultured until the third passage. DFMSCs were labeled with Quantum dot 655 for cell tracking analysis. The induction of the SS mouse model was performed by the injection of Ro60-273-289 peptide intraperitoneally. DFMSCs were injected intraperitoneally, or into submandibular, or lacrimal glands. Splenocytes were analyzed for intracellular cytokine (IFN-γ, IL-17, IL-10) secretion in T helper cells, lymphocyte proliferation, and B lymphocyte subsets. Histologic analysis was done for submandibular and lacrimal glands with hematoxylin-eosin staining for morphologic examination. RESULTS: The systemic injection of DFMSCs significantly reduced intracellular IFN-γ and IL-17 secreting CD4+ T cells in splenocytes (p<0.05), and decreased inflammatory cell deposits and fibrosis in the glandular tissues. DFMSCs differentiated to glandular epithelial cells in submandibular and lacrimal injections with a significant reduction in lymphocytic foci. The results showed that few amounts of DFMSCs were deposited in glandular tissues when applied intraperitoneally, while high amounts of DFMSCs were located in glandular tissues and differentiated to glandular epithelial cells when applied locally in SS murine model. CONCLUSION: DFMSCs have the potential for the regulation of Th1, Th17, and Treg balance in SS, and ameliorate glandular dysfunction. DFMSCs can be a beneficial therapeutic application for SS.

Immunoregulatory effects of dental mesenchymal stem cells on T and B lymphocyte responses in primary Sjögren's syndrome.

Background: In this article, the authors investigate the modulatory effects of dental mesenchymal stem cells (MSCs) on lymphocyte responses in primary Sjögren's syndrome (pSS), which is an autoimmune disease resulting from keratoconjunctivitis sicca and xerostomia. Methods: Mononuclear cells isolated from pSS patients cultured with or without dental MSCs and analyzed for lymphocyte responses via flow cytometry. Results: Dental-follicle (DF)- and dental-pulp (DP)-MSCs downregulated CD4+ T lymphocyte proliferation by increasing Fas-ligand expression on T lymphocytes and FoxP3 expressing Tregs, and decreasing intracellular IFN-γ and IL-17 secretion in pSS patients. DF-MSCs decreased the plasma B cell ratio in the favor of naive B cell population in pSS patients' mononuclear cells. Conclusion: DF- and DP-MSCs can be the new cellular therapeutic candidates for the regulation of immune responses in pSS.

Plain language summary In this article, the authors investigate the modulatory effects of dental mesenchymal stem cells (dental MSCs) on lymphocyte responses in primary Sjögren's syndrome (pSS), which is characterized by the infiltration of lymphocytes in exocrine glands. Lymphocyte proliferation, apoptosis, Tregs and total Bregs, intracellular cytokine secretion, total memory, plasma and naive B cell subsets were analyzed in pSS patients and compared them with healthy individuals. Dental follicle- and dental pulp-MSCs modulated CD4⁺ T lymphocyte responses in pSS patients' mononuclear cells by increasing Fas-ligand expression, enhancing FoxP3-expressing Tregs, and decreasing pro-inflammatory cytokine secretion. Our findings provide evidence for the potential role of dental-MSCs as a cellular therapy option in the treatment of pSS.

Replacement of maxillary lateral incisors with digitally manufactured single tooth retained all-ceramic pontics: a clinical report / Reabilitação da região de incisivo lateral superior ausente por pôntico modelo cantiléver em cerâmica pura fabricado digitalmente: relato de caso clínico

Several treatment options for replacement of anterior missing teeth exist, varying from no-prep (no preparation) adhesive restorations to implants. Patients' biological, psychological, economic conditions or age have an effect on the treatment choice. It is important to perform the most conservative and beneficial treatment option considering the patient based factors. The aim of this case report was to demonstrate a single session, minimally invasive, cantilevered 2-unit all-ceramic restorations replacing anterior missing teeth combined with the advantages of CAD/CAM technology and materials. (AU)

Existem várias opções de tratamento para reabilitação de dentes anteriores ausentes, variando de restaurações adesivas sem preparo (sem preparação) até implantes. As condições biológicas, psicológicas, econômicas ou a idade dos pacientes têm um efeito na escolha do tratamento. É importante realizar a opção de tratamento mais conservadora e benéfica, considerando os fatores baseados no paciente. O objetivo deste relato de caso foi demonstrar em sessão única, minimamente invasiva, um cantiléver de restaurações de cerâmica pura de 2 unidades, reabilitando a região de dentes anteriores ausentes combinadas com as vantagens da tecnologia CAD/CAM.(AU)

In vivo wear determination of novel CAD/CAM ceramic crowns by using 3D alignment.

PURPOSE: To determine wear amount of single molar crowns, made from four different restoratives, and opposing natural teeth through computerized fabrication techniques using 3D image alignment. MATERIALS AND METHODS: A total of 24 single crowns (N = 24 patients, age range: 18 - 50) were made from lithium disilicate (IPS E-max CAD), lithium silicate and zirconia based (Vita Suprinity CAD), resin matrix ceramic material (Cerasmart, GC), and dual matrix (Vita Enamic CAD) blocks. After digital impressions (Cerec 3D Bluecam, DentsplySirona), the crowns were designed and manufactured (Cerec 3, DentsplySirona). A dual-curing resin cement was used for cementation (Variolink Esthetic DC, Ivoclar). Then, measurement and recording of crowns and the opposing enamel surfaces with the intraoral scanner were made as well as at the third and sixth month follow-ups. All measurements were superimposed with a software (David-Laserscanner, V3.10.4). Volume loss due to wear was calculated from baseline to follow-up periods with Siemens Unigraphics NX 10 software. Statistical analysis was accomplished by Repeated Measures for ANOVA (SPSS 21) at = .05 significance level. RESULTS: After 6 months, insignificant differences of the glass matrix and resin matrix materials for restoration/enamel wear were observed (P>.05). While there were no significant differences between the glass matrix groups (P>.05), significant differences between the resin matrix group materials (P<.05) were obtained. Although Cerasmart and Enamic were both resin matrix based, they exhibited different wear characteristics. CONCLUSION: Glass matrix materials showed less wear both on their own and opposing enamel surfaces than resin matrix ceramic materials.

Color assessment after bleaching with hydrogen peroxide versus ozone: a randomized controlled clinical trial.

This randomized controlled clinical trial evaluated the color change of teeth bleached with either hydrogen peroxide (HP) or ozone (OZ). A total of 26 patients with a mean age of 36.2 years (SD, 8.7 years) who met the inclusion criteria were enrolled in the study. The subjects were randomly assigned to receive chairside bleaching using 40% HP or gaseous OZ. Maxillary dental arch vacuum trays were constructed with circumferential openings in the middle portion of the maxillary incisors at their labial surfaces. These trays were used for measuring color-first at baseline and then immediately and 48 hours after postbleaching-and were not used in bleaching. Changes in color were determined using CIE L*a*b* coordinates. Analysis of the data revealed that, while overall color change (ΔE*) values of the HP and OZ groups did not show statistically significant differences immediately after bleaching (P = 0.114), ΔE* values were significantly different 48 hours postbleaching (P = 0.00). Visible color changes were not obtained with either HP or OZ immediately postbleaching. The greatest visible color change occurred with HP 48 hours postbleaching.

Evaluation of Different Thickness, Die Color, and Resin Cement Shade for Veneers of Multilayered CAD/CAM Blocks.

PURPOSE: To investigate the effect of resin cement color on the post-cementation shade of thin laminate veneers milled from multilayered glass ceramic blocks for each layer. MATERIALS AND METHODS: Thin slices (N = 180) with two thicknesses (A: 8 × 8×0.55 mm and B: 8×8×0.8 mm; n = 90/group) were obtained from multilayered glass ceramic blocks using a diamond saw. Resin die specimens were prepared (8 × 8 × 4 mm) (n = 180) and divided into two resin cement colors (D: -3. L: +3) and one control group (C: translucent). Each slice was luted to the composite specimens using a dual-curing resin cement under a constant load of 250 g and light-polymerized for 120 seconds. Specimens were placed on a white background and CIELab values for each layer of the blank slices (incisal [In], body [Bo], and cervical [Ce]) were recorded using a dental contact spectrophotometer. The values were calculated as ΔE, and the data were statistically analyzed (one-way ANOVA, Shapiro-Wilk). RESULTS: Mean ΔE values for A and B were significant (p < 0.05) for In (A: 6.2 ± 1.1; B: 6.6 ± 1.2), Bo (A: 5.1 ± 2.6; B: 3.9 ± 1), and Ce (A: 5.3 ± 2.7; B: 3.8 ± 1.2). Mean ΔE values for In for D and L for A and B groups were significantly higher (6.3 ± 1.2; 6.6 ± 1.2) than Bo and Ce for D (4.4 ± 2.4; 4.6 ± 2.6) and L (4.6 ± 1.4; 4.5 ± 1.7) groups (p < 0.05), respectively. Mean differences between Bo and Ce for A and B groups were insignificant (p ≥ 0.05), while for In the differences were significant. Mean differences between Bo and Ce for A (5.1 ± 2.6; 5.3 ± 2.7) and for B (3.9 ± 1; 3.5 ± 1.2) groups were insignificant (p ≥ 0.05), while for In the differences were significant (6.2 ± 1.1 for A and 6.6 ± 1.2 for B). CONCLUSION: The color changes for body and cervical regions of multilayered ceramic veneers were not affected by resin color or ceramic thickness, but the incisal area was affected. The translucency of each layer in ceramic veneer fabricated with multilayered blanks should be considered for clinical situations.

Effect of different cleaning regimens on the adhesion of resin to saliva-contaminated ceramics.

PURPOSE: The aim of this study was to evaluate the influence of different cleaning regimens on the microshear bond strength (µSBS) of three different all-ceramic surfaces after saliva contamination. MATERIAL AND METHODS: Cubic ceramic specimens (3 × 3 × 3 mm(3) ) were prepared from three types of ceramics: zirconium dioxide (Z), leucite-reinforced glass ceramic (E), lithium disilicate glass ceramic (EX; n = 12/subgroup). A total of 144 composite resin cylinders (diameter: 1 mm, height: 3 mm) were prepared. Three human-saliva-contaminated surfaces of ceramic specimens were cleaned with either water spray (WS), with 0.5% sodium hypochlorite solution (HC), or with a cleaning paste (CP). Control surface (C) was not contaminated or cleaned. Composite cylinders were bonded to each surface with a resin luting cement. All specimens were stored at 37°C in deionized water until fracture testing. µSBS tests were performed in a universal testing machine (0.5 mm/min), and the results (MPa ± SD) were statistically analyzed (two-way ANOVA, Bonferroni a = 0.05). Fractured surfaces were analyzed to identify the failure types using an optical microscope at 50× magnification. Two representative specimens from all groups were examined with scanning electron microscopy. RESULTS: µSBS test results were significantly affected by the saliva cleaning regimens (p = 0.01) and the ceramic types (p = 0.03). The interaction terms between the ceramic type and saliva cleaning regimen were also significant (p < 0.05). There were no significant differences among the µSBS values (MPa ± SD) for the Z group (C = 17.5 ± 8.8; WS = 16.0 ± 4.9; HC = 17.6 ± 5.8; CP = 16.6 ± 7.5; p > 0.05). In the EX group, C resulted in significantly higher µSBS values (32.6 ± 7.4) than CP (17.4 ± 8.9), WS (15.6 ± 7.3), and HC (14.3 ± 4.5) (p < 0.05); however, C (20.4 ± 7.1) and HC (19.2 ± 7.5) showed higher µSBS values than CP (13.8 ± 4.8) and WS (10.9 ± 5.7) in the E group. Some cohesive failures within the luting resin were observed in the E and EX groups, whereas only adhesive failures were seen in zirconia groups for all surface treatments. CONCLUSIONS: Different ceramic surface cleaning regimens after saliva contamination of the zirconium dioxide revealed µSBS similar to the control group, whereas all surface cleaning regimens tested significantly decreased the bond strength values in the lithium disilicate glass ceramic. The leucite-reinforced glass-ceramic group benefited from 0.5% sodium hypochlorite solution cleaning with increased bond strengths. CLINICAL SIGNIFICANCE: Adhesive cementation of zirconia presents a clinically challenging protocol, and the cementation surface contamination of the zirconia restorations and the inadequate removal of the contaminants increase the risk of failure, as for all ceramic types. This study demonstrated that surface cleaning regimens should be applied according to different ceramic properties.

Color changes of dental resin composites before and after polymerization and storage in water.

UNLABELLED: The aims of this study were to: (1) evaluate the A2 shades of various types and brands of resin composites to determine if any color differences occurred before and after polymerization and after 1 month of storage in water and (2) examine the correlation among the color changes and changes in Commission internationale de l'éclairage L*, a*, and b* values after polymerization and after 1 month of storage in water. One submicron-hybrid (Spectrum TPH3, DENTSPLY DeTrey, Milford, DE, USA), one nano-filled (Filtek Supreme XT, 3 M ESPE, St. Paul, MN, USA), three micro-hybrid (Filtek Z250, 3 M ESPE; Esthet X, DENTSPLY DeTrey; and Gradia Direct, GC, Tokyo, Japan), and five nano-hybrid (Ceram X, DENTSPLY DeTrey; Clearfil Majesty Esthetics, Kuraray, Osaka, Japan; Premise, Kerr Corporation, Orange, CA, USA; Tetric Evo Ceram, Ivoclar Vivadent, Schaan, Liechtenstein and Tetric N Ceram, Ivoclar Vivadent) light-curing resin composites were tested. The specimens (N = 10 for each composite) were prepared as discs, 12 mm in diameter and 2 mm in thickness, using round molds. The measurements were performed "before polymerization,""after polymerization," and "after 1 month of storage in water" using a contact type dental spectrophotometer (Vita Easyshade, Vident, Brea, CA, USA). The range of ΔE* values after polymerization (ΔE*1) and storage in water (ΔE*2) were 4.59 to 14.13 and 1.26 to 6.29, respectively. Nested analysis of variance and post hoc tests revealed that the type of resin composites significantly affected Δa*1, Δa*2, Δb*1, Δb*2, ΔE*2-values, whereas the brand of resin composites affected the changes in all color parameters (p < 0.05). In spite of many improvements in chemical compositions and fillers of the contemporary composites, color changes after polymerization were perceptible in all resin composites. However, color changes after storage in water were in the acceptable ranges for all resin composites except Clearfil Majesty Esthetic and Gradia Direct. CLINICAL SIGNIFICANCE: In spite of many improvements in chemical compositions and fillers of the contemporary resin composites, the color changes after polymerization were still perceptible in all the resin composites tested in this study, regardless of their types and brands. Such changes may cause esthetic problems clinically, thus should be taken into account when the shade selections are performed. Alternatively, a piece of unpolymerized resin material can be placed on, or adjacent to the tooth to be restored and polymerized to confirm the selected shade of the esthetic material.

Effects of soldering and laser welding on bond strength of ceramic to metal.

STATEMENT OF PROBLEM: Welding or soldering of metal frameworks negatively affects the overall bond strength between the veneering ceramic and metal. PURPOSE: The purpose of this study was to evaluate the effect of soldering and laser-welding procedures on the bond strength between ceramic and metal. MATERIAL AND METHODS: Thirty Ni-based metal specimens (Wiron 99) (8 × 4 × 4 mm) were fabricated and divided into 3 groups; soldered (S), laser welded (L), and control (untreated cast alloy) (n=10). In S and L specimens, a notch (1 × 1.5 mm) was prepared longitudinally on the surface of each specimen and filled with compatible alloy (Wiron soldering rods and Wiroweld NC, respectively). Vickers hardness measurements were made after polishing the surfaces with a metallographic polishing kit. A veneering ceramic (VITA VMK 95) was vibrated, condensed in a mold, and fired on the metal frameworks. The specimens were sectioned in 2 axes to obtain nontrimmed bar specimens with a bonding area of approximately 1 mm². Forty bars per block were obtained. Each bar was subjected to microtensile bond strength (µTBS) testing with a crosshead speed of 1 mm/min. The µTBS data (MPa) were recorded, and SEM was used for failure analysis of the tested bars. The measurements were statistically analyzed using a 1-way ANOVA and Tamhane tests (α=.05). RESULTS: The mean differences in µTBS of veneering ceramic to soldered (10.4 ±2.4 MPa) and laser-welded (11.7 ±1.3 MPa) metal surfaces were not significantly different and were significantly lower than that of the cast alloy (25.4 ±3.6 MPa) (P<.05). The mean Vickers hardness of cast alloy was significantly higher (236 ±17 HV) than soldered (114 ±9 HV) and laser-welded groups (129 ±11 HV) (P<.05). CONCLUSIONS: Soldering and laser welding significantly decreased the µTBS of a veneering ceramic to a base metal alloy.

One-year clinical evaluation of the efficacy of a new daytime at-home bleaching technique.

The aim of this study was to compare the clinical efficacy and side effects of a new daytime at-home bleaching technique (28% carbamide peroxide [CP] gel) with the overnight application of 10% CP and to determine the change of tooth color 1-year post-treatment. Twenty healthy volunteers were assigned to one of two sample groups of 10. All participants employed one of the two at-home bleaching systems: (1) the new daytime at-home bleaching system including 28% CP gel with a non-custom-fit tray (Meta Tray, Remedent, Deurle, Belgium) for 20 minutes, and (b) the conventional overnight at-home bleaching system with a 10% CP gel and a custom-fit tray (Opalescence PF, Ultradent, South Jordan, UT, USA) for 6 to 8 hours. Digital images and CIE (International Commission on Illumination) L*, a*, and b* spectrophotometric measurements were taken at baseline, after the bleaching treatment and 1-year post-treatment. Tooth and gingival sensitivity was measured with a specially designed 4-point scale. Significant differences were found in L*, a*, and b* values, between initial and post-treatment, for both bleaching systems (p < 0.05). However, no significant difference was detected between post-treatment and 1-year follow-up. The bleaching effectiveness of Opalescence PF was found to be superior to that of Meta Tray, considering the color parameter of DeltaE (p < 0.05). Meta Tray provoked less tooth sensitivity (p < 0.05), however gingival sensitivity appeared more in this group (p < 0.05). Within the limitations of this study, it can be concluded that the new daytime at-home bleaching system tested (Meta Tray) produced significant bleaching effects. However, the clinical efficacy of the overnight bleaching system was found to be superior to the daytime at-home bleaching system evaluated in this study. The whitening effect remained similar 1-year after the bleaching treatment for both at-home bleaching systems. CLINICAL SIGNIFICANCE Although the new daytime at-home bleaching system tested exhibited significant bleaching effects, overnight bleaching with a 10% CP gel resulted in a higher bleaching effectiveness than this new system. Although the participants using the new bleaching system exhibited less tooth sensitivity probably because of the reduced contact time of bleaching gel with tooth surfaces, the application of the bleaching agent with a non-customized tray provoked more gingival sensitivity in this group.

Color analysis of different ceramic systems.

This study compared the color properties of three different ceramic systems. Three groups of 10 specimens each were prepared: Dental porcelain alloy was used as a framework for conventional and ProBOND metal-ceramic systems, while glass-ceramic ingots were used as a framework for 10 samples using an all-ceramic system. For the former, dentin porcelain was applied and a ceramic veneering material was applied to the ingot frameworks. Using a dental spectrophotometer, the pre- and post-glaze color compatibility between disc specimens and A3 shade was evaluated. The Kruskal-Wallis test was used to compare color differences among groups in this study, while the Mann-Whitney U test was used to make bilateral comparisons among the three different ceramic systems. The values obtained during the dentin stage revealed a significant difference in the all-ceramic group (p < 0.05). After glazing, there was no significant difference between ProBOND samples and all-ceramic samples (p > 0.05). These results suggest that ProBOND can yield esthetically superior results in clinical applications compared to conventional ceramic systems.

Prosthetic rehabilitation of hemimandibular hyperplasia: five-year follow-up.

Hemimandibular hyperplasia is a rare asymmetrical mandibular malformation, characterized by enlargement of the condyle, the condylar neck, the ramus, and the body of the mandible. This condition results in laterognathia, dental articulation disorders, and functional defects. Therapy largely depends on the patient's age and the desired esthetic and functional results. This clinical report describes the prosthetic rehabilitation of a 50-year-old woman with hemimandibular hyperplasia. During the diagnostic phase, facial asymmetry was observed, as was the chin midline shifting to the unaffected side and three-dimensional enlargement of one side of the mandible, the condyle, the condylar neck, and the ramus. No biomechanical or functional problems were seen at a five-year follow-up visit, except for physiological wear to the artificial teeth.

Color stability of nanocomposites polished with one-step systems.

OBJECTIVE: This study compared the color changes of five novel resin composites polished with two one-step polishing systems when exposed to coffee solution. METHODS: The resin composites tested were Filtek Supreme XT, Grandio, CeramX, Premise and Tetric EvoCeram. A total of 150 discs (30/resin composites, 10 x 2 mm) were fabricated. Ten specimens/resin composites cured under Mylar strips served as the control. The other samples were polished with PoGo and OptraPol discs for 30 seconds using a slow speed handpiece and immersed in coffee (Nescafé) for seven days. Color measurements were made with Vita Easyshade at baseline and after one and seven days. Repeated Measures ANOVA and Bonferroni tests were used for statistical analyses (p< or =0.05). RESULTS: The differences between the mean DeltaE* values for the resin composites polished with two different one-step systems were statistically significant (p<0.05). After one week, all materials exhibited significant color changes compared to baseline. All Mylar finished specimens showed the most intense staining (p<0.05). There were no significant differences between the OptraPol and PoGo polished groups. Mylar-finished specimens of CeramX, Tetric EvoCeram, Premise and Filtek Supreme XT presented the greatest staining (p<0.05). For Grandio, there were no significant differences between the Mylar and PoGo groups, while the most stain resistant surfaces were attained with OptraPol. CONCLUSION: Removing the outermost resin layer by polishing procedures is essential to achieving a stain resistant, more esthetically stable surface. One-step polishing systems can be used successfully for polishing nanocomposites.