Salivary, acidic and enzymatic degradation of resin composite subjected to different finishing and polishing systems.

PURPOSE: To evaluate the effect of different finishing and polishing systems on the surface roughness of a resin composite subjected to simulated saliva-, acid-, and enzyme-induced degradation. METHODS: 160 specimens (n= 40) were fabricated with Filtek Z350 XT nanofilled composite and analyzed for average surface roughness (Ra). The specimens were finished and polished using: AD - Al2O3-impreginated rubberized discs (medium, fine, and superfine grit, Sof-Lex); SD - silicon carbide and Al2O3-impregnated rubberized discs (coarse, medium and fine grit, Jiffy,); MB - 12- and 30-multiblade burs. The control group (CT) (n= 40) comprised specimens with a Mylar-strip-created surface. Specimens from each group were immersed in 1 mL of one of the degradation methods (n= 10): artificial saliva (ArS: pH 6.75), cariogenic challenge (CaC: pH 4.3), erosive challenge (ErC: 0.05M citric acid, pH 2.3) or enzymatic challenge (EzC: artificial saliva with 700 µg/mL of albumin, pH 6.75). The immersion period simulated a time frame of 180 days. Ra measurements were also performed at the post-polishing and post-degradation time points. The data were evaluated by three-way ANOVA for repeated measures and the Tukey tests. RESULTS: There was significant interaction between the finishing/polishing system and the degradation method (P= 0.001). AD presented the greatest smoothness, followed by SD. After degradation, CT, AD and SD groups became significantly rougher, but not the MB group, which presented no difference in roughness before or after degradation. CT and AD groups showed greater roughness in CaC, ErC and EzC than in ArS. The SD group showed no difference in roughness when the specimens were polished with CaC, EzC or ArS, but those treated with ErC had greater roughness. In the MB group, the lower roughness values were found after using CaC and EzC, while the higher values were found using ErC or ArS. CLINICAL SIGNIFICANCE: As far as degradation resistance of nanofilled composite to hydrolysis, bacterial and dietary acids and enzymatic reactions is concerned, restorations that had been finished and polished with Al2O3-impregnated discs had the smoothest surfaces.

Effect of toothbrushing with conventional and whitening dentifrices on monolithic zirconia after finishing procedures.

PURPOSE: To evaluate the effect of toothbrushing with conventional and whitening dentifrices on the color difference (ΔE00), gloss (Δgloss), and surface roughness (SR) of stained stabilized zirconia with 5 mol% of yttrium oxide (5Y-TZP) after polishing or glazing. METHODS: Specimens were divided into four groups (n=20): C (control), S (staining), SG (staining and glazing) and SP (staining and polishing). 50,000 toothbrushing cycles were performed with conventional (n=10) and whitening (n= 10) dentifrice slurries. The ΔE00 and Δgloss were measured using a spectrophotometer and CIEDE2000 system while SR was measured by laser confocal microscope. The ΔE00 and Δgloss data were analyzed using 2-way ANOVA, and SR data were analyzed using the linear repeated measures model, with Bonferroni's complementary test (α= 0.05). RESULTS: The ΔE00 values were beyond the acceptability threshold and no differences were found among the groups. There was no difference among groups to Δgloss after toothbrushing with conventional dentifrice while SP presented the highest values of Δgloss after toothbrushing with whitening dentifrice. Conventional dentifrice decreased the SR of stained groups and whitening dentifrice decreased SR of S and SG. The toothbrushing with conventional and whitening dentifrices promoted color difference, but did not impair gloss and surface roughness of stained 5Y-TZP. CLINICAL SIGNIFICANCE: Monolithic zirconia has been routinely used for esthetic restorations, however the type of finishing procedures that is carried out on it must be taken into consideration, in addition to the fact that brushing can influence the color difference of the material as well as interfere with surface roughness and gloss.

In-vitro biofilm removal from TiUnite® implant surface with an air polishing and two different plasma devices.

BACKGROUND: We investigated the efficacy of two different cold atmospheric pressure jet plasma devices (CAP09 and CAPmed) and an air polishing device with glycine powder (AP) either applied as monotherapies or combined therapies (AP + CAP09; AP + CAPmed), in microbial biofilm removal from discs with anodised titanium surface. METHODS: Discs covered with 7-day-old microbial biofilm were treated either with CAP09, CAPmed, AP, AP + CAP09 or AP + CAPmed and compared with negative and positive controls. Biofilm removal was assessed with flourescence and electron microscopy immediately after treatment and after 5 days of reincubation of the treated discs. RESULTS: Treatment with CAP09 or CAPmed did not lead to an effective biofilm removal, whereas treatment with AP detached the complete biofilm, which however regrew to baseline magnitude after 5 days of reincubation. Both combination therapies (AP + CAP09 and AP + CAPmed) achieved a complete biofilm removal immediately after cleaning. However, biofilm regrew after 5 days on 50% of the discs treated with the combination therapy. CONCLUSION: AP treatment alone can remove gross biofilm immediately from anodised titanium surfaces. However, it did not impede regrowth after 5 days, because microorganisms were probably hidden in holes and troughs, from which they could regrow, and which were inaccessible to AP. The combination of AP and plasma treatment probably removed or inactivated microorganisms also from these hard to access spots. These results were independent of the choice of plasma device.

Effects of Coloring Liquid Dipping Time and Surface Finishing Procedures on the Optical Properties of Monolithic Zirconia.

BACKGROUND: Monolithic zirconia restorations can be produced from self-colored or uncolored blocks. The coloring procedure of uncolored blocks and surface treatments may affect the appearance of the restoration. AIM: The purpose of this study is to evaluate the effect of liquid coloring and surface treatments on optical properties of translucent monolithic zirconia. METHODS: All specimens were cut from zirconia blocks with a thickness of 1 mm. Specimens were dipped in the coloring liquids for 3 min, 5 min, and 7 min and then divided into groups of 10 specimens for surface treatments. Glaze and mechanical polishing were applied, and the color of the specimens was measured under the D65 lighting condition with a spectrophotometer device. Color values obtained from the CIE Lab formula and the translucency parameter (TP), opalescence parameter (OP), and contrast ratio (CR) were calculated. The normality of the data was confirmed with the Shapiro-Wilk test. A three-way analysis of variance (ANOVA) was used to assess the effect of dipping time, liquid shade, and surface treatments. RESULTS: The effect of liquid shade and dipping time on the TP, OP, and CR parameters were statistically significant, and the TP values were reduced with the application of coloring liquid. Mechanical polishing groups had higher OP values and lower TP values than glazed groups. CONCLUSION: In cases where high translucency is required, it may be advisable to use self-colored blocks and apply glaze as a surface treatment to achieve the desired optical properties.

Influence of airborne particle abrasion on dentin bonding effectiveness of a 2-step universal adhesive.

OBJECTIVE: To determine the effect of airborne particle abrasion (APA) on micro-tensile bond strength (µTBS) to dentin using different air-abrasion/polishing powders. METHODS: The bonding effectiveness of G2 Bond Universal (G2B), used in etch-and-rinse (E&R) and self-etch mode (SE), was tested on bur-cut dentin and dentin air abraded/polished using six different powders (aluminum oxide 29 µm (AO29) and 53 µm (AO53), aluminum trihydroxide (AT), sodium bicarbonate (SB), sodium bicarbonate soft (SBsoft) and bioactive glass (BG); Velopex). Adhesive-composite resin specimens were immersed in distilled water at 37 °C for one week and cut into microspecimens. Half of the specimens were subjected to 50,000 thermocycles (aged). Immediate and aged µTBS to dentin were measured. Statistical analysis was performed using linear mixed-effects (LME) modeling (p < 0.05). RESULTS: Comparing the aged bond strengths to air-abraded/polished dentin with bur-cut dentin, pretreatment with SB and SBsoft in combination with G2B used in E&R mode, and BG air polishing in combination with both application modes (E&R, SE), resulted in a significantly higher bond strength. Dentin bond strength was only significantly lower when air abraded with AO29 and using G2B in SE mode. Aging did not significantly influence bond strength for both application modes (E&R, SE), except for AO29 and AT-treated dentin, where bond strengths decrea sed significantly using G2B in SE mode. In general, G2B reached significantly higher bond strengths on air-abraded/polished dentin in E&R mode than in SE mode. CONCLUSION: Air-abrasion/polishing did not impair dentin bond strength using G2B, except when dentin was air abraded with AO29 and using G2B in SE mode. Air polishing positively influenced the bond strength to dentin in specific groups. CLINICAL SIGNIFICANCE: APA is safe concerning bonding to dentin. The E&R application mode is preferred using G2B as adhesive on air-abraded/polished dentin. Air polishing with BG positively influenced dentin bond strength for both application methods.

Effect of dry and wet finishing and polishing on color change and opacity of nanofill and nanohybrid composites.

BACKGROUND: As superior esthetic is one of the main reasons for using composite resins, it is very important to be familiar with factors and techniques affecting their optical properties and appearance. AIM: The aim of this study was comparing the effect of finishing and polishing with and without water coolant, on the color change and opacity of composite resin materials. METHODS: Composites used for preparing samples were Z250 (microhybrid), Z350XT (nanofilled), and Z550 (nanohybrid). Then divided into 4 groups of 5 depending on finishing and polishing technique (dry or wet) and time (immediate and after twenty-four hours). After polishing, samples were assessed using a spectrophotometer. Color change and opacity were determined. Data was analyzed using Kolmogorov-Smirnov, ANOVA and Tukey HSD tests. RESULTS: Type of material at both time had a significant effect on ΔE and opacity. Our results in dry and wet technique immediately(T0) showed that the highest and lowest ΔE and opacity belong to Z350XT (p < 0.001). After Twenty-four hours (T24), opacity of Z250 in wet condition was higher than dry condition (p < 0.001). CONCLUSIONS: Wet or dry technique was only effective on color in immediate polishing. Regarding opacity, technique was only effective in case of delayed polishing.

Experimental validation of mechanical oscillating IPR system.

BACKGROUND: Interproximal enamel reduction (IPR) is a clinical procedure which involves reduction and anatomic recontouring of interproximal surfaces of enamel as a method of gaining space. The biological effects related to this clinical procedure have long been discussed. Thus, the aim of this study was to evaluate the enamel reduction efficiency and the effects on enamel surfaces of the oscillating mechanical system for interproximal enamel reduction (IPR). METHODS: Fifteen complete oscillating IPR sequences included one opener (0.1 mm), two metallic strips for active IPR phase (0.2 and 0.3 mm), three resin strips for active and initial polishing phases (0.4 and 0.5 mm), and one resin strip for polishing phase (0.15 mm). Sequences were selected and tested on fifteen freshly extracted teeth by means of tribological tests with alternative dry-sliding motion (Linear Reciprocating Tribometer; C.S.M. Instruments, Peseaux, Switzerland). A 3D analysis of treated surfaces was performed by using a TayMap software. Then, enamel surfaces were qualitatively evaluated before and after the tribological analysis, with a FEI Quanta 200 (FEI, Hillsboro, OR, USA) in high vacuum at 30.00 kV. Images were acquired at a 30×, 100× and 300× magnification. RESULTS: Minimum surface irregularities were observed on all treated enamel surfaces when compared with untreated ones. The 3D analysis showed a uniform wear pattern after tribological tests. Meanwhile, the SEM analysis revealed smooth and regular wear lines on treated surfaces after the entire mechanical IPR sequence. The macroscopic irregularities illustrated can be considered similar to those of untreated surfaces. CONCLUSIONS: The adoption of a standardized oscillating IPR sequence allows an efficient reduction of the interproximal enamel, leaving regular and harmonious surfaces. Adequate polishing procedures should always be performed at the end of active IPR phases in order to guarantee a good long-term prognosis and proper respect of biological structures.

Effect of different surface and heat treatments on the surface roughness, crystallography, and phase composition of high translucency zirconia for monolithic restorations.

STATEMENT OF PROBLEM: High translucency zirconia (HTZ) has gained popularity as an esthetic computer-aided design and computer-aided manufacturing (CAD-CAM) material for monolithic restorations. A detailed comparison between different common surface and heat treatments with a non-treated HTZ control to explain the behavior of the material under stress is lacking. PURPOSE: The purpose of this in vitro study was to evaluate the effect of different surface and heat treatments on the surface roughness parameters (SRPs), topography, crystallography, and phase composition of HTZ used for monolithic restorations. MATERIAL AND METHODS: Ninety Ø11.9×1.18-mm HTZ disks (Prettau Anterior) were milled, sintered, and distributed into 9 groups (n=10); 8 experimental (coarse diamond grinding GC, fine diamond grinding GF, fine diamond grinding and 3-step polishing kit GF+P1, fine diamond grinding and 3-step polishing kit and diamond paste GF+P1+DP, fine diamond grinding and 2-step polishing kit GF+P2, fine diamond grinding and GF+Gl, fine diamond grinding and 3-step polishing and glazing GF+P1+Gl, airborne-particle abrasion with 50-µm alumina), and a control group (C, as-sintered). SRPs (AveSa, AveSv, AveSz) and 3-dimensional (3D) images were obtained using a noncontact 3D-optic-profilometer. The crystal structure was determined with scanning electron microscopy. Phase composition was analyzed by X-ray diffraction (XRD). Surface roughness parameters data were statistically analyzed by 1-way ANOVA and the Tukey HSD test (α=.05). RESULTS: The applied surface and heat treatment resulted in significantly different SRP mean values (P<.001) with different topographies. GC had the highest AveSa, AveSv, and AveSz mean values (0.95, 8.8, 17.4 µm, respectively) with significant microcracks. GF had significantly lower SRP with finer microcracks. GF+P1 had a significantly smoother surface, but GF+P2 resulted in SRP comparable with the GF group. GF+P1+DP had the smoothest homogenous surface (mean Sa: 0.08 µm). GF+P1 and GF+GL were equally effective, while GF+P1+GL was not superior. Airborne-particle abrasion produced a low Sa mean value (0.11 µm) with relatively high Sv and Sz mean values (5.9, 9.2 µm, respectively) and microcracks. A monoclinic phase was detected in all groups. All experimental groups had broadened XRD-peaks with lower intensity, suggesting the presence of the rhombohedral phase. CONCLUSIONS: The different surface and heat treatments altered the HTZ crystals and their surface roughness with distinct topographies. Cubic crystal changes take place under stress as shown by the scanning electron microscope and the XRD diffraction pattern and may transform to the rhombohedral phase.

Effect of simplified or multi-step polishing techniques on roughness and color stability of resin composites.

PURPOSE: To evaluate the impact of simplified or multi-step polishing techniques on the roughness, color, and susceptibility to staining of different resin composites. METHODS: Discs (Ø6 mm x 2 mm) were obtained from different resin composites [nanofilled (Z350XT), suprananofilled (Estelite Omega), and nanohybrid (Forma)]. The specimens (n= 15) were submitted to a simplified protocol using abrasive discs (Sof-Lex) and spiral discs (Diacomp Plus Twist), or a multi-step protocol using abrasive discs (Sof-Lex), abrasive points (Jiffy), silicon carbide brush and felt disc with diamond pastes (Diamond Polish). The specimens were evaluated initially for roughness (Ra) and color (CIEL*a*b*, CIEDE 2000), after completing the polishing protocol, and after exposure to a coffee solution (pH= 5.01). The data were analyzed according to the variables, using generalized linear models, and the Friedman, Nemenyi, Kruskal-Wallis, Dunn, and Mann-Whitney tests (α= 0.05). RESULTS: The nanohybrid resin composite showed an increase in Ra following use of both polishing methods (P= 0.038). Both techniques promoted an increase in L* values after polishing; however, the general color changes (ΔEab and ΔE00) were greater after the multi-step polishing (P< 0.05). After immersion in coffee, the multi-step polished groups of the nanohybrid and suprananofilled resin composite showed higher L* values than the simplified polishing groups (P= 0.023), and the nanofilled resin composite showed higher ΔEab and ΔE00 values than the other resin composites, regardless of the polishing technique (P< 0.05). CLINICAL SIGNIFICANCE: The choice of the resin composite had a greater effect on roughness, color stability and susceptibility to staining than the polishing technique. However, luminosity after coffee staining was higher with the multi-step polishing technique.

Evaluation of Glazing and Polishing Systems for Novel Chairside CAD/CAM Lithium Disilicate and Virgilite Crowns.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of glazing, two zirconia, and two lithium disilicate polishing systems on surface roughness of a CAD/CAM lithium disilicate and virgilite ceramic with atomic force microscopy (AFM) and visual assessment performed by dental students and faculty. METHODS AND MATERIALS: Sixty maxillary right central incisor crowns made of a novel chairside CAD/CAM lithium disilicate and virgilite (CEREC Tessera) were milled for glazing and polishing. The crowns were divided into six groups: no polishing/glazing provided (NoP/G); glazed (GZ); glazed and polished with Brasseler Dialite LD Lithium Disilicate (DiLD); glazed and polished with Meisinger Luster Lithium Disilicate (LuLD); glazed and polished with Brasseler Dialite ZR Zirconia (DiZR); and glazed and polished with Meisinger Luster Zirconia (LuZR). Surfaces were scanned with AFM to measure roughness (Ra) and root mean square roughness (Rq) and generate micrographs. Crowns were visually assessed by 10 dental students and 10 dental school faculty members to determine clinical acceptableness. RESULTS: Glazing and all polishing kits significantly reduced Ra and Rq compared to no polishing/glazing. No significant Ra differences were found between glazing and all polishing kits (p>0.05). DiZR significantly reduced Rq compared to other groups (p<0.05). Visual assessment showed that GZ, LuLD, and DiZR were the most clinically acceptable crowns. CONCLUSION: Polishing and glazing considerably improve the surface smoothness of maxillary central incisor crowns fabricated out of a chairside CAD/CAM lithium disilicate and virgilite ceramic. Altogether, zirconia polishing systems provided smoother and more clinically acceptable surfaces than the lithium disilicate kits.

Spectrophotometric assessment of the color stability of composite resins polished with different techniques.

This study aimed to use spectrophotometry to assess the color stability of composite resins polished with different polishing techniques and scanning electron microscopy (SEM) to evaluate the surface micromorphology of the specimens. In this in vitro experimental study, a total of 96 disc-shaped specimens were fabricated from microfilled (Renamel Microfill, shade SB3) and nanohybrid (Estelite Sigma Quick, shade BW) composite resins in bright white shades (n = 48). Each group was randomized into 1 control and 2 experimental subgroups (n = 16): no polishing (control), polishing with aluminum oxide discs (experimental), or polishing with diamond-impregnated spiral wheels (experimental). In each subgroup, half of the specimens were immersed in a coffee solution and the other half in a tea solution for 48 hours after finishing (control) or polishing (experimental). Spectrophotometry was used to measure the color of the specimens at baseline, after finishing, after polishing (experimental groups only), and after immersion in tea and coffee. The surface micromorphology of a randomly selected specimen from each subgroup was assessed under SEM. The color change (ΔE*) of the specimens between measurements was calculated and analyzed using 1-way, 2-way, and 3-way analyses of variance (ANOVAs) and the Tukey test. Both tea and coffee caused significant color change in the composite resin specimens, with specimens immersed in coffee undergoing significantly greater color change than those immersed in tea (P < 0.001; 2-way ANOVA). The nanohybrid composite specimens polished with polishing discs had a significantly greater color change than nanohybrid specimens polished with spiral wheels (P = 0.041). The Tukey test revealed that there was no overall significant difference between the 2 polishing techniques (P = 0.505), but both of these subgroups exhibited a significantly lower color change than the control group (P < 0.001). In general, SEM did not reveal substantial differences between the 2 polishing techniques, but specimens polished by spiral wheels appeared to have a smoother surface. All polished specimens demonstrated clinically acceptable mean color change values (ΔE* < 3.5). The type of coloring agent had a greater effect on color stability than either the polishing technique or type of composite resin, with coffee causing a greater color change than tea.

Effect of chemical or mechanical finishing/polishing and immersion in staining solutions on the roughness, microhardness, and color stability of CAD-CAM monolithic ceramics.

During the manufacture of ceramic restorations there is an important step of finishing and polishing and the effects of different types of these procedures on the surface characteristics of ceramics are not known for sure. AIM: To evaluate the effects of various surface treatments and immersion in coloring substances on the roughness, microhardness, and color stability of CAD-CAM monolithic ceramics. MATERIALS AND METHOD: The ceramics used were lithium disilicate reinforced with zirconium dioxide (Suprinity), lithium disilicate (E.max) or leucite (Empress). They were subjected to two surface treatments: glazing (group G) (n=20) or mechanical polishing (group P) (n=20). Then they were divided into two subgroups (n=10) to be treated with the staining substance (coffee or water). Roughness, microhardness and color were measured before and after treatment. Data were subjected to analysis of variance and multiple comparisons were performed with Tukey tests at 5% significance level. RESULTS: Roughness was lower in all tested ceramics after polishing than after glazing. Microhardness was the same for polished and glazed E.max, higher in glazed than polished Empress, and higher in polished than glazed Suprinity. Analysis of the effects of glazing and polishing on the individual ceramics showed that the ΔE2000 and ΔWID data of the E.max ceramic subjected to polishing showed greater change. Mechanical polishing is a good option for surface treatment of monolithic ceramics. CONCLUSION: Glazing was inferior and less satisfactory than polishing. Glazing generates changes that can lead to color instability.

Durante a confecção de restaurações cerâmicas existe uma importante etapa dos procedimentos de acabamento e polimento. Os efeitos de diferentes tipos desses procedimentos nas características superficiais das cerâmicas não são conhecidos com certeza. Objetivo: Avaliar os efeitos de vários tratamentos de superfície e imersão em substâncias corantes na rugosidade, microdureza e estabilidade de cor de cerâmicas monolíticas CAD-CAM. Materiais e Métodos: As cerâmicas utilizadas foram dissilicato de lítio reforçado com dióxido de zircônio (Suprinity), dissilicato de lítio (E.max) ou leucita (Empress). Foram submetidos a dois tratamentos de superfície: glazeamento (grupo G) (n=20) ou polimento mecânico (grupo P) (n=20). Em seguida, foram divididos em dois subgrupos (n=10) para serem tratados com a substância corante (café ou água). Rugosidade, microdureza e cor foram medidas antes e após o tratamento. Os dados foram submetidos à análise de variância e as comparações múltiplas foram realizadas com testes de Tukey ao nível de 5% de significância. Resultados: A rugosidade foi menor em todas as cerâmicas testadas após o polimento do que após o glazeamento. A microdureza foi a mesma para o E.max polido e vidrado, maior no Empress vidrado do que no polido, e maior no Suprinity polido do que no vidrado. A análise dos efeitos do esmaltação e polimento nas cerâmicas individuais mostrou que os dados ΔE2000 e ΔWID da cerâmica E.max submetida ao polimento apresentaram maior alteração. O polimento mecânico é uma boa opção para o tratamento superficial de cerâmicas monolíticas. Conclusão: A aplicação do glazing foi inferior e menos satisfatório que o polimento, gerando alterações que podem levar à instabilidade da cor.

Efeito dos diferentes tipos de polimento sobre a rugosidade de superfície de uma resina acrílica comercial quimicamente ativada: estudo in vitro / Effect of different types of polishing on the surface roughness of a chemically activated commercial acrylic resin: an in vitro study

Objetivo: avaliar in vitro o polimento sobre resina acrílica quimicamente ativada (RAQA), por meio da rugosidade de superfície (Ra). Materiais e Método: Foram confeccionadas 40 amostras de RAQA, com dimensões de 10 a 10 x 2 mm, e foram divididas em quatro grupos (n=10): ausência do acabamento (AA); Ausência de polimento (AP); Polimento químico (PQ); Polimento com borrachas siliconadas + Escovas (PM). Os espécimes foram avaliados no quanto a rugosidade média (Ra) antes e após o envelhecimento em água destilada em uma estufa por 60 dias. Três medições de Ra (µm), na horizontal foram realizadas e calculada uma média para cada espécime. Os dados foram analisados de forma descritiva e inferencial, ANOVA de medidas repetidas e teste de Tukey com nível de significância de 5%. Resultados: Inicialmente, o grupo AA teve os menores valores de Ra e o grupo AP os maiores valores de rugosidade, com média e desvio padrão respectivamente 0,17 (±0,11) e 0,52 (±0,10). Após o envelhecimento, o grupo AA teve as menores médias e o grupo PQ os maiores valores de Ra, sendo 0,38 (±0,20) e 1,33 (±0,32), respectivamente. Os resultados evidenciaram diferença estatística significante quando as amostras foram submetidas ao acabamento com brocas. Conclusão: A RAQA necessita de polimento após acabamento com brocas, uma vez que a ausência de polimento comprometerá a lisura de superfície do material.(AU)

Objective: to evaluate in vitro polishing on chemically activated acrylic resin (RAQA), using surface roughness (Ra). Materials and Method: 40 RAQA samples were made, measuring 10 to 10 x 2 mm, and divided into four groups (n=10): absence of finishing (AA); Lack of polishing (AP); Chemical polishing (PQ); Polishing with silicone rubbers + Brushes (PM). The specimens were evaluated for their average roughness (Ra) before and after aging in distilled water in an oven for 60 days. Three horizontal Ra (µm) measurements were taken and an average was calculated for each specimen. Data were analyzed descriptively and inferentially, using repeated measures ANOVA and Tukey test with a significance level of 5%. Results: Initially, the AA group had the lowest Ra values and the AP group the highest roughness values, with mean and standard deviation respectively 0.17 (±0.11) and 0.52 (±0.10). After aging, the AA group had the lowest averages and the PQ group the highest Ra values, being 0.38 (±0.20) and 1.33 (±0.32), respectively. The results showed a statistically significant difference when the samples were finished with drills. Conclusion: RAQA requires polishing after finishing with drills, as the lack of polishing will compromise the surface smoothness of the material.(AU)

Evaluation of surface roughness and color changes of restorative materials used with different polishing procedures in pediatric dentistry.

This study aimed to evaluate the color stability and surface roughness properties of four different restorative materials used in pediatric dentistry clinics as a result of four different polishing procedures. A total of 128 samples, 32 of each restorative material, were prepared by placing them in polyethylene molds with a diameter of 6 mm and a height of 2 mm, in accordance with the instructions of the manufacturers, to be polished with four different polishing procedures (n = 8). After finishing and polishing, the samples were kept in distilled water at 37 °C for 24 hours. Surface roughness and color stability measurements of the samples were then made. The Hysitron TI 950 TriboIndenter device in Mustafa Kemal University's Technology Research & Development Center was used for surface roughness test measurements, and the Ra parameter was taken as a basis. A spectrophotometer instrument (VITA Easyshade® Advance 4.0 (VITA Zahnfabrik, Bad Sackingen, Germany)) was used to determine color stability and color differences were recorded according to the CIEDE 2000 system. The lowest roughness values ​​were observed in G-aenial restorative material polished with Super-Snap material, and the highest roughness values ​​were observed in Equia material polished with Identoflex material. When all materials were evaluated, the smallest color change values ​​were seen in G-aenial material polished with Super-Snap, and the most color change values ​​were detected in Equia material polished with Identoflex. It was observed that the relationship between surface roughness and color change was statistically significant. The lowest color change and surface roughness values were observed in the G-aenial material polished with Super-Snap. For improved clinical results, the most appropriate polishing procedure should be chosen based on the restorative material used.

Finishing and Polishing Procedures and Glaze Application on Physical Properties of a Fine-Structure Feldspathic Ceramic.

The aim of this study was to verify the effect of finishing and polishing procedures and glaze application on biaxial strength and surface properties of milled feldspathic ceramic blocks. Forty disc-shaped samples (14 mm diameter, 1.2 mm thickness) were divided in four groups (n = 10): C (control): no finishing and polishing; FP: finishing and polishing; G: glaze; and GFP: finishing and polishing + glaze. The specimens were subject to surface gloss (glossmeter) and roughness (profilometer) tests followed by biaxial flexural strength (universal testing machine) and Vickers hardness (microhardness tester) tests. The surface morphological analysis was performed by scanning electron microscopy (n = 3). Data were submitted to normality tests with Shapiro-Wilk, and one-way ANOVA followed by Tukey's post hoc test (α = 0.05). Group C showed the lowest gloss. For the hardness test, groups C, FP, and GFP obtained the highest values without significant differences between them. Regarding the biaxial strength test, group C showed the lowest mean value. Both finishing and polishing methods (FP and GFP) showed surface properties similar or better than the control, and with higher biaxial strength.

Is surface roughness of direct resin composite restorations material and polisher-dependent? A systematic review.

STATEMENT OF PROBLEM: Direct resin composite bonding offers a highly esthetic, minimally invasive option for the treatment of anterior teeth however the challenge to improve their longevity remains. Direct resin composite restorations are limited by the risk of staining which may be influenced by the final surface roughness (Ra) of composite achieved. PURPOSE: The purpose of this review is to investigate, using a systematic approach, whether the final surface roughness of anterior composite restorations is affected by the interaction between resin composite and polishing systems. MATERIALS AND METHODS: The review was conducted by 3 independent reviewers and included articles published up to January 21, 2021. Three electronic databases were searched: Medline, Embase, and Web of Science. Studies assessing a quantitative effect of polishing methods on the Ra of direct composite resin materials published after the year 2000 and restricted to the English language were included. RESULTS: The database search for the effect of polishing systems on composite materials retrieved 125 eligible studies. Twelve duplicate records were removed. The resulting records were screened using title and abstract leading to 38 reports which were sought for retrieval. Application of eligibility criteria led to 11 studies included in the review. Hand searching of these studies yielded no additional papers. CONCLUSIONS: There is insufficient evidence to determine whether combination of composite and polisher influences final Ra. More research is required to determine if there is an optimum combination of polisher and composite. CLINICAL IMPLICATIONS: Polishing should be completed following planned finishing procedures. The approximation to the final surface and which finishing burs to use, if any, should be considered when planning a restoration. Durafill VS predictably achieves an acceptable Ra by different polishers.

Strength of a Zirconia- Reinforced Glass-Ceramic After Diamond Bur Adjustment.

INTRODUCTION: Adjustments with diamond burs on the ceramic surface can affect its roughness and decrease flexural strength. This study evaluated the effect of polishing or glazing on the surface roughness and biaxial flexural strength of a zirconia-reinforced lithium silicate glass-ceramic upon adjustment with diamond burs. METHODS: Seventy disks were prepared according to ISO 6872 and divided into seven groups (n = 10) according to different adjustments and finishing processes. Surface roughness was measured prior to biaxial flexural strength testing. The topography was analyzed using an atomic force microscope , fracture markings were identified using a stereomicroscope and representative specimens were analyzed using scanning electron microscopy. RESULTS: The use of diamond burs significantly increased the surface roughness and decreased the strength of the evaluated ceramic (p⟨0.05). Polishing reduced the ceramic's roughness but resulted in flexural strength similar to that of the groups with wear (p⟩0.05). The glaze-treated specimens showed flexural strength statistically similar to the control group (p>0.05) but higher roughness, similar to those with wear. CONCLUSIONS: Polishing reduced the surface roughness but did not affect the biaxial flexural strength of the ZLS ceramic. At the same time, the application of glaze after wear increased the strength.

Impact of polishing system on surface roughness of different ceramic surfaces after various pretreatments and bracket debonding.

OBJECTIVE: Evaluating various polishing methods after bracket debonding and excessive attachment material removal for different ceramics and pretreatments. MATERIAL AND METHODS: Zirconia (ZrO2), leucite (LEU) and lithium disilicate (LiSi) specimens were pretreated with a) silica coated alumina particles (CoJet); LEU and LiSi additionally with b) hydrofluoric acid (HF), c) Monobond Etch&Prime (MEP), d) silicium carbide grinder (SiC) before bracket bonding, shearing off, ARI evaluation, excessive attachment material removal and polishing with i) Sof-Lex Discs (Soflex), ii) polishing paste (Paste), iii) polishing set (Set). Before/after polishing surface roughness (Ra) was measured with a profilometer. Martens hardness parameter were also assessed. RESULTS: Irrespective of pretreatment Ra of LEU increased the most, followed by LiSi and ZrO2 (p < 0.001, SiC: p = 0.012), in accordance with the measured Martens hardness parameter. CoJet/SiC caused greater roughness as HF/MEP (p < 0.001). The ZrO2 surface was rougher after polishing with Paste/Set (p < 0.001; p = 0.047). Ra improved in the LEU/CoJet, LEU/SiC and LiSi/SiC groups with Soflex/Set (p < 0.001), in the LiSi/CoJet and LEU/HF groups by Soflex (p = 0.003, p < 0.001) and worsened by Paste (p = 0.017, p < 0.001). Polishing of HF or MEP pretreated LiSi with Set increased Ra (p = 0.001, p < 0.001), so did Paste in the LEU/MEP group (p < 0.001). CONCLUSIONS: Paste couldn't improve the surfaces. Soflex was the only method decreasing Ra on rough surfaces and not causing roughness worsening. Polishing of LEU/LiSi after MEP, LEU after HF pretreatment doesn´t seem to have any benefit. CLINICAL RELEVANCE: To avoid long-term damage to ceramic restorations, special attention should be paid to the polishing method after orthodontic treatment.

Effects of in-office bleaching agents on polished and unpolished nanofilled resin composite.

BACKGROUND: This study investigates the effects of in-office bleaching agents on the color change and surface roughness of nanofilled resin composite finished by various polishing procedures. METHODS: The authors made 108 specimens from nanofilled resin composite, and the finishing and polishing procedures were performed with either Sof-Lex (3M ESPE) or OneGloss (Shofu). The specimens were then immersed in tea or coffee solution for 1 week, after which in-office bleaching agents were applied (n = 9). After polishing and bleaching, the surface roughness was measured with a surface profilometer. The specimen color parameters were measured with the Commission Internationale de l'Eclairage L∗a∗b∗ system in 3 stages, namely after polishing, after staining, and at the end of the bleaching procedure. The total color changes (ΔEab∗) were calculated, and ΔEab∗ not exceeding 2.7 was considered a clinically acceptable threshold. RESULTS: The highest initial roughness value was observed on surfaces polished with OneGloss. In all groups, the surface roughness increased significantly after bleaching. For the Sof-Lex group specimens stained in both tea and coffee solutions, bleaching agent Opalescence Boost (Ultradent) reduced the color change value to 2.7 or less after bleaching. CONCLUSIONS: In-office bleaching agents increased surface roughness in all groups, especially on unpolished surfaces. However, surface roughness was at an acceptable threshold for the multistep polished group, Sof-Lex, after bleaching. Nanofilled resin composite staining can be partially reduced by in-office bleaching agents but not completely removed. PRACTICAL IMPLICATIONS: To reduce the increase in surface roughness of composite restorations due to bleaching, polishing should be applied before and after bleaching.

Impact of Finishing and Polishing Procedures on CAD/CAM In Vitro Milled Ceramics Surfaces: A Systematic Review.

INTRODUCTION AND OBJECTIVES: CAD/CAM prostheses may be produced in prosthetic laboratories or directly by practitioners. Quality of ceramic polishing procedures is a controversial topic and it would be interesting for practitioners working with CAD/CAM devices to determine which method is the most efficient regarding finishing and polishing. This systematic review aims to evaluate the impact of different finishing and polishing procedures on the surface of milled ceramics. MATERIALS AND METHODS: A precise request was launched on the PubMed database. Studies included if they met the criteria of a specifically prepared PICO search. A first selection was performed by analysing titles and abstracts: the articles presenting a study conducted on non-CAD/CAM milled ceramics and research not containing comparisons of finishing procedures were not included. Roughness was evaluated in 15 articles. Nine papers recommended mechanical polishing over glazing regardless of the type of ceramic used. However, no significant differences were detected between the surface roughness of glazed and polished ceramics in nine other publications. CONCLUSIONS: there is no scientific evidence demonstrating the superiority of hand polishing over glazing on CAD/CAM-milled ceramics.