Investigation of Water Absorption and Color Change of Indirect Composite Resins

Purpose:Since conventional composite resins have some disadvantages such as polymerization shrinkage and secondarycaries formation, indirect restorations are preferred in cases where tooth tissue loss is high. The aim of this study is toexamine the water absorption and color change of indirect composite resins in different beverages.Materials & Methods:In the study, 40 specimens (10×2 mm) were arranged from each composite using three indirect(Signum Composite, Signum Ceramis and Gradia Plus) and one conventional (GrandioSO) composite resin. After thespecimens were polished, they were used for water absorption and color change test. The water absorption test wasperformed through keeping them in water for 7 days as specified in ISO 4049:2009. Samples were kept in coffee, tea anddistilled water for 7 days in order to examine color differences. The water absorption and color change values of thecomposite resins at the end of the 7th day were appraised using one-way analysis of variance (ANOVA) and Tukey’s test(p<0.05).Results:While there was no statistically considerable difference between the water absorption data of the indirect andtraditional composite resin materials we used in the study (p>0.05). When the color changes of resin-containingcomposites in water, coffee and tea were examined, traditional composite resin (GrandioSO) showed statistically lesscolor change than indirect composites in water, coffee and tea (p<0.05).Conclusion:Although indirect composite resins showed similar water absorption with conventional composite, theyshowed more color change than conventional composite. The highest color change in indirect composites was seen incoffee solution. Particle size of the indirect composites do not affect water absorption, but the decrease in particle size ofcomposites shows less color change.

Degradation Potential of Bulk Versus Incrementally Applied and Indirect Composites: Color, Microhardness, and Surface Deterioration

SUMMARY This study investigated the color stability and microhardness of five composites exposed to four beverages with different pH values. Composite discs were produced (n=10); Filtek Z250 (3M ESPE) and Filtek P90 (3M ESPE) were applied in two layers (2 mm, 20 seconds), and Tetric N-Ceram Bulk Fill (TetricBF, Ivoclar Vivadent) and SonicFill (Kerr) were applied in bulk (4 mm) and then light cured (40 seconds, Ortholux-LED, 1600 mW/cm2). Indirect composite Sinfony (3M ESPE) was applied in two layers (2 mm) and cured (Visio system, 3M ESPE). The specimens were polished and tested for color stability; ΔE was calculated using spectrophotometer readings. Vickers microhardness (50 g, dwell time=45 seconds) was assessed on the top and bottom surfaces at baseline, 40 days of storage, subsequent repolishing, and 60 days of immersion in distilled water (pH=7.0), Coca-Cola (pH=2.3), orange juice (pH=3.75), or anise (pH=8.5) using scanning electron microscopy (SEM). The materials had similar ΔE values (40 days, p&gt;0.05), but TetricBF had a significantly greater ΔE than P90 or SF (40 days). The ΔE was less for P90 and TetricBF than for Z250, SonicFill, and Sinfony (60 days). Repolishing and further immersion significantly affected the ΔE (p&lt;0.05) except for P90. All composites had significantly different top vs bottom baseline microhardnesses. This was insignificant for the Z250/water, P90/orange juice (40 days), and Sinfony groups (40 and 60 days). Immersion produced variable time-dependent deterioration of microhardness in all groups. Multivariate repeated measures analysis of variance with post hoc Bonferroni tests were used to compare the results. ΔE and microhardness changes were significantly inversely correlated at 40 days, but this relationship was insignificant at 60 days (Pearson test). SEM showed degradation (40 days) that worsened (60 days). Bulk-fill composites differ regarding color-stability and top-to-bottom microhardness changes compared with those of other composites. P90 showed better surface degradation resistance. In conclusion, bulk-fill composites are not promising alternatives to incremental and indirect composites regarding biodegradation.

Flexural strength of composites: effects of the activation techniques and fiber reinforcement.

<p class="western" lang="en-US" align="justify"><span style="font-family: Arial, sans-serif;"><span><strong>Objective</strong></span></span><span style="font-family: Arial, sans-serif;"><span>: To evaluate the flexural strength of direct (Charisma) and indirect (Solidex) composites, with or without fiber reinforcements (Ribbond), cured with LED or Stroboscopic Xenon Light.</span></span><span style="font-family: Arial, sans-serif;"><span><strong>Material</strong></span></span><span style="font-family: Arial, sans-serif;"><span><strong>and</strong></span></span><span style="font-family: Arial, sans-serif;"><span><strong>Methods</strong></span></span><span style="font-family: Arial, sans-serif;"><span>: Resin bars made with or without fiber reinforcements, with 25mm x 2mm x 2mm were distributed in groups (n=10): G</span></span><span style="font-family: Arial, sans-serif;"><span><span>DL</span></span></span><span style="font-family: Arial, sans-serif;"><span>– Direct Resin/LED; G</span></span><span style="font-family: Arial, sans-serif;"><span><span>DX</span></span></span><span style="font-family: Arial, sans-serif;"><span>–Direct Resin/Stroboscopic Xenon; G</span></span><span style="font-family: Arial, sans-serif;"><span><span>DFL</span></span></span><span style="font-family: Arial, sans-serif;"><span>– Direct Resin/Fiber/LED; G</span></span><span style="font-family: Arial, sans-serif;"><span><span>DFX</span></span></span><span style="font-family: Arial, sans-serif;"><span>– Direct Resin/Fiber/Stroboscopic Xenon; G</span></span><span style="font-family: Arial, sans-serif;"><span><span>IL</span></span></span><span style="font-family: Arial, sans-serif;"><span>– Indirect Resin/LED; G</span></span><span style="font-family: Arial, sans-serif;"><span><span>IX</span></span></span><span style="font-family: Arial, sans-serif;"><span>– Indirect Resin/Stroboscopic Xenon; G</span></span><span style="font-family: Arial, sans-serif;"><span><span>IFL</span></span></span><span style="font-family: Arial, sans-serif;"><span>– Indirect Resin/Fiber/LED; G</span></span><span style="font-family: Arial, sans-serif;"><span><span>IFX</span></span></span><span style="font-family: Arial, sans-serif;"><span>– Indirect Resin/Fiber/Stroboscopic Xenon. The specimens were connected to a universal test machine and submitted to a compression load </span></span><span style="font-family: Arial, sans-serif;"><span><span>(2 kN).</span></span></span><span style="font-family: Arial, sans-serif;"><span><strong>Results</strong></span></span><span style="font-family: Arial, sans-serif;"><span>: </span></span><span style="font-family: Arial, sans-serif;"><span><span>The obtained results were submitted to Analysis of Variance tests (p &lt; 0.01), and Tukey (5% significance level) tests. The flexural strength of groups that used polyethylene fiber reinforcement (96.39) was similar (p = 0.58) to group without fiber reinforcement (92.47). Direct composites (107.79) showed higher values of flexural strength than indirect composites (81.07), and stroboscopic xenon light curing (108.71) resulted in better flexural strength results than LED (80.15), for both kinds of composites experimented</span></span></span><span style="font-family: Arial, sans-serif;"><span>. </span></span><span style="font-family: Arial, sans-serif;"><span><strong>Conclusion</strong></span></span><span style="font-family: Arial, sans-serif;"><span>: The fiber reinforcement did not improve the composites’ flexural strength, direct composites showed higher flexural strength values, and stroboscopic xenon light showed better flexural strength results. </span></span></p><p class="western" lang="en-US" align="justify"><span style="font-family: Arial, sans-serif;"><span><strong>Keywords</strong></span></span></p><p class="western" lang="en-US" align="justify"><span style="font-family: Arial, sans-serif;"><span>Composite resins; Curing Lights; Fiber reinforcements; Physical properties.</span></span></p>

The Effect of Prophylactic Polishing Pastes on Surface Roughness of Indirect Restorative Materials

The purpose of this study was to evaluate the influence of prophylactic polishing pastes (PPP; Detartrine (DT), Topex (TP)) on surface roughness (Ra) of indirect composites (IRC; Tescera (TES), Gradia (GRD), and Estenia C&B (EST)), a glass ceramic (Empress 2 layering (E2)), and a leucite reinforced glass ceramic (Empress Esthetic (EE)) with two different (glazed (G); polished (P)) surface preparations. A total of 90 IRC and 120 ceramic discs, 8 mm in diameter and 2 mm thick, were prepared. E2 and EE specimens were randomly divided into two groups(n=30). One group was glazed (GE2; GEE), while the other group was polished (PE2; PEE) the same as the IRCs. The specimens in each group were subsequently divided into three subgroups: control (C), DT, and TP.Ra (μm) was evaluated with a profilometer. Data were analyzed by Kruskal Wallis, followed by the Dunn's multiple comparison testsP<0.05. DT and TP resulted in significant surface roughening for TES, GRD, and EST, while no significant differences were detected between DT and TPP>0.05. PE2 and PEE were not affected by DT or TPP>0.05, while GE2 and GEE exhibited significant roughening after TPP<0.05. Surface roughness of IRCs and glazed ceramics can be affected by PPP applications.

Surface roughness of indirect composites using different polishing systems

<p><strong>Objective: </strong>The aim of this study was to evaluatethe surface roughness of indirect composites afterpolishing with aluminum oxide (Al2O3) discs. <strong>Materialand Methods</strong>: One-hundred and eighty specimenswere confectioned with 6 indirect composites using aprefabricated matrix, resulting in six groups (n-30):Group SO - Solidex, Group SI - Signum, Group SF- Sinfony, Group OP - Opallis; Group RE - Resilab,Group EP - Epricord, Group AD - Adoro. Each groupwas divided into three subgroups according to thepolishing (n-10): Subgroup C (Control) - withoutpolishing (polyester strip); Subgroup S - polishingwith Sof-Lex discs; Subgroup T - polishing with TDVdiscs. The surface roughness was measured with aprofilometer. <strong>Results: </strong>The results were analyzed byANOVA and Tukey tests (5%), resulting in p = 0.00.The mean values (±standard-deviation) measured inRa (μm) for each Group/Subgroup were: RE/C - 0.14(± 0.14) a; EP/C - 0.18 (± 0.46) ab; SO/C - 0.24 (±0.22) abc; SF/S - 0.24 (± 0.17) abc; SF/C - 0.26 (±2.54)abc; SI/C - 0.30 (± 0.34)abcd; SO/T - 0.33(±0.42) abcd; AD/S - 0.34(± 0.88)abcd; AD/C - 0.37(±0.60)ab; SI/S - 0.37(± 1.39)bcd; SO/S - 0.43(± 0.26)cd; EP/S – 0.44 (± 1.02) cd; RE/S - 0.54(±2.02) de;SI/T - 0.65(± 0.88)ef; RE/T - 0.83 (± 0.54) fg; SF/T- 0.85 (± 0.21) fg; AD/T - 0.88 (± 1.74) fg; EP/T- 0.91(± 0.89) g. <strong>Conclusion: </strong>It is concluded thatpolyester strip resulted in significantly lowest surfaceroughness; polishing with TDV discs resulted insignificantly higher surface roughness compared toSof-Lex discs and that the surface roughness resultsdepend on the composite tested.</p><p>Keywords<br />Composite resins; Dental polishing; Biofilms.</p>