Polishing Protocols Research Articles

Factors Affecting the Wear Behavior of Monolithic Zirconia and the Antagonists: Literature Review

Background:The use of zirconia-based ceramics to produce monolithic restorations has increased due to improvements in the optical properties of the materials. Traditionally, zirconiabased ceramics were veneered with porcelain or glass-ceramic and were not directly exposed to the oral environment. Therefore, there are several doubts regarding the wear of the monolithic zirconia restoration and their antagonists. Additionally, different surface treatments are recommended to promote a smooth surface, including glaze and several polishing protocols. To support the correct clinical application, it is important to understand the advantages and limitations of each surface treatment.Objective:The aim of this short literature review is to investigate the factors that may affect the wear of monolithic zirconia restorations in service and their antagonists.Methods:Pubmed/Medline database was accessed to review the literature from a 10-year period using the keywords: zirconia, monolithic, prosthesis, wear. Both clinical and in vitro studies were included in the review.Results:Studies investigated the effect of several surface treatments, including grinding with diamond- burs, polishing and glazing, on the surface roughness, phase transformation and wear capacity of monolithic zirconia. The wear behavior of monolithic zirconia was frequently compared to the wear behavior of other ceramics, such as feldspathic porcelain, lithium disilicate-based glassceramic and leucite-reinforced glass-ceramic. Human tooth, ceramics and resin composites were used as antagonist in the investigations. Only short-term clinical studies are available (up to 2 years).Conclusion:Literature findings suggest that zirconia monolithic restorations are wear resistant and unlikely to cause excessive wear to the antagonist, especially when compared to feldspathic porcelain and glass-ceramics. Monolithic zirconia should be polished rather than glazed. Yet, none of the polishing systems studied was able to completely restore the initial surface conditions of zirconia after being adjusted with burs. More clinical evidence of the antagonist tooth wear potential of monolithic zirconia is needed.

Simulated clinical adjustment and intra-oral polishing of two translucent, monolithic zirconia dental ceramics: An in vitro investigation of surface roughness

ObjectiveTo assess the surface roughness and residual flaws in two translucent zirconia substrates following simulated clinical adjustment and intra-oral finishing/polishing. Materials and methodsSpecimens were prepared from two translucent (5Y-ZP/8Y-ZP) and one conventional (3Y-TZP) zirconia substrates (n = 84 p/g). Arithmetic mean roughness parameter (Ra) was determined for all experimental groups at four stages (n = 21 p/g): (1) as-sintered, (2) surface grinding using a zirconia cutting diamond bur, (3) polishing using 1-step, 2-step or 4-step intra-oral polishing kits, and (4) laboratory polishing/glazing. Scanning electron microscopy (SEM) was used to evaluate residual surface flaws. Data were statistically analysed using a two-way ANOVA test, multiple and pairwise comparisons were performed using a Bonferroni post hoc test. ResultsRa was significantly higher for as-sintered and ground 5Y-ZP/8Y-ZP compared to 3Y-TZP (p ≤ 0.001). Material type and polishing protocol had statistically significant effect on Ra (p < 0.001). The 4-step polishing resulted in the lowest Ra in 3Y-TZP/5Y-ZP (p ≤ 0.001). No significant differences were observed between different polishing protocols in 8Y-ZP (p≥0.655). Glazing significantly reduced Ra in all materials compared to other polishing protocols (p ≤ 0.001) except for the 4-step protocol in 3Y-TZP (p = 0.195). SEM revealed pronounced surface flaws in ground 5Y-ZP/8Y-ZP. Grinding of 3Y-TZP induced ductile material removal and thereby, minimal cohesive material loss. The 4-step polishing protocol resulted in the fewest and shallowest surface flaws in all groups. Glazing of 3Y-TZP resulted in the most homogenous surface contrary to 5Y-ZP/8Y-ZP. ConclusionsThe finest surface finish was achieved using the 4-step polishing protocol in all studied materials. This protocol might be inadequate however for polishing of ground 5Y-ZP/8Y-ZP as a result of the pronounced surface damage induced by the grinding process. The glazing of 5Y-ZP/8Y-ZP might not be as predictable as for 3Y-TZP. Clinical significanceThe higher susceptibility to surface damage, as a result of increasing dopant concentration, may render polishing of ground, translucent zirconia more complicated compared to the conventional 3Y-TZP counterparts.

In-vitro polishing of CAD/CAM ceramic restorations: An evaluation with SEM and confocal profilometry

AimThe objective of this In-vitro investigation was to analyze and compare the surface after polishing of 63 all-ceramic restorations fabricated out of monolithic zirconium dioxide (ZIR), lithium disilicate (LS) or feldspathic ceramic (FC) under standardized laboratory conditions with different protocols. The primary outcome was defined as the roughness (Ra/Sa) of different ceramic surfaces after distinctive polishing procedures. Material and methodsThe study set-up consisted of three main groups: ZIR, LS, FC (20 crowns each), every group divided into two sub-groups (10 crowns each) depending on the polishing method. The untouched glazed surface of one crown per material served as a control. Every crown displayed a defined supra-contact at the palatal cusp which was removed with a fine grain (38–45 μm) diamond bur. Surface polishing was carried out with either a two-step system (one kit for zirconium dioxide (ZIR2), another kit for lithium disilicate (LS2) and feldspatic ceramic (FC2)), or a three-step system (ZIR3, LS3, FC3) under standardized conditions. Roughness parameters (Ra and Sa) were measured by means of confocal profilometry. Specimens were also visually inspected with scanning electron microscopy (SEM). Statistical analyses were performed using SPSS Statistics software. ResultsVisual examination of the specimens using SEM showed several inhomogeneities on the glazed surface of the control samples, i.e. pores and particles. On every test sample, the grinding curves of the diamond bur were still recognizable. Polishing revealed similar median Ra 0.491 μm (ZIR2) and 0.434 μm (LS2) after two-step polishing (p = 0.754), and 0.311 μm (ZIR3) and 0.208 μm (LS3) after three-step polishing (p = 0.917). Surface roughness in group FC measured 0.889 μm (FC2) after the two-step polishing process and 0.903 μm (FC3) following three-step surface refinement. No significant difference was detectable between surface roughness of glazed controls compared to either polished surfaces with two-step or three-step treatment within one material. ZIR and LS presented significantly lower median roughness Ra after two-step and three-step procedures than test samples of FC, measured subsequent to either of the polishing methods (p = 0.016, p = 0.009). ConclusionThe surface roughness of ZIR, LS and FC crowns after the use of chairside polishing kits was comparable with the roughness measured before occlusal adjustment. A two-step procedure showed as good results as a three-step process. A smoother surface was obtained for ZIR and LS compared to FC with both polishing protocols.

Evaluation of the effects of polishing systems on surface roughness and morphology of dental composite resin.

Objectives The aim of this in vitro study was to evaluate the effects of five different two-step diamond impregnated polishing systems (Sof-Lex Spiral, Venus Supra, Komet Spiral, CompoMaster and Shapeguard) on the surface roughness and morphology of a submicron hybrid composite resin material (Brilliant Everglow).Materials and methods Two-hundred composite resin discs were prepared with 180 SiC paper to produce a uniform baseline surface. The samples were randomly assigned to one of five groups and polishing was completed by one operator. The arithmetic mean surface roughness (Ra) was measured using contact profilometry and the surfaces were examined under an SEM.Results Statistical differences (p <0.05) were identified between the surface roughness remaining after use of the polishers. Diatech Shapeguard (0.22 μm, SD 0.08) and Komet Spiral (0.26 μm, SD 0.09) polishers yielded the lowest Ra values, while the CompoMaster polishing system led to the highest surface roughness values (0.55 μm, SD 0.19).Conclusions Within the limits of this in vitro study of the efficacy of diamond impregnated two-step polishing systems, Diatech Shapeguard and Komet Spiral polishing systems produced the lowest surface roughness values. These polishing systems yielded acceptable surface roughness values with regards to oral health and patient comfort.Clinical relevance Similarly designed polishing systems do not produce comparable surface roughness levels and clinicians should be aware of this when considering polishing protocols for composite restorations.

The Effect of a Polishing Protocol on the Surface Roughness of Zirconium Oxide.

To evaluate the surface roughness values of zirconium oxide samples that were gradually polished using a commercially available polishing system and polishing paste. A total of 50 rectangular specimens of predetermined size (10 × 10 × 3 mm) were sintered from zirconium oxide. Samples were randomly assigned to one of five groups (n = 10 each): control, coarse (Co), fine (F), super fine (SF), or polishing paste (PP). In the control group, no polishing was done; in the Co group, a coarse polisher was used; and the specimens in the remaining three groups underwent additional processing with a fine rubber abrasive. For SF and PP samples, subsequent treatment with a super fine polisher was applied. Finally, for the PP group, a goat-hair brush with diamond polishing paste was used. An optical profilometer was used to evaluate roughness average (Ra) in micrometers (μm). ANOVA and Games-Howell post hoc tests were utilized to detect differences between groups. The significance level was set to α = .05. Surface roughness gradually decreased with further polishing throughout the groups: control Ra = 0.525 ± 0.099 μm; Co Ra = 0.252 ± 0.038 μm; F Ra = 0.196 ± 0.035 μm; SF Ra = 0.114 ± 0.031 μm; and PP Ra = 0.054 ± 0.020 μm. Statistically significant differences were detected among all groups (P < .05). A surface roughness of 0.054 μm can be achieved if a full zirconia polishing protocol is used. Zirconium oxide can be polished to various surface roughnesses using commercially available polishing products.

Improving teeth aesthetics using a spatially shared-parameters model for independent regular lattices

ABSTRACT An important feature in dentistry is teeth gloss. During an intervention, the doctor applies a resin and a polishing to achieve the lowest roughness and the highest gloss possible. This work aims to evaluate the effect of four polishing protocols in teeth surface roughness and gloss when combined with two different resins and eventually indicate the best combination (treatment). An atomic force microscope is used for measuring the in vitro roughness of a dental surface surrogate. We consider a shared parameters approach for linking the information carried by those two correlated variables. The model fitted to the gloss considers some features of the roughness, namely the information conveyed by a set of spatial structured random effects, specific to each treatment, and the within treatment variance, which allows interpreting how the heterogeneity and the variability of the surface roughness impacts a tooth gloss. The statistical model here developed is an alternative to the “traditional” two-way ANOVA used in dentistry journals. The results, using the recent R-NIMBLE package in R, show that variability characteristics of the surface's roughness are central for explaining differences among the gloss achieved after each treatment and not just the mean roughness of that surface.

Effects of Different Polishing Protocols and Curing Time on Surface Properties of a Bulk-fill Composite Resin.

To determine the effects of different polishing protocols and curing times on the surface roughness (SR), surface gloss (SG) and surface hardness (SH) of a bulk-fill composite resin (BCR). A total of 30 block-shaped specimens (40 mm long × 10 mm wide × 2 mm thick) were made from Filtek Bulk-Fill composite resin and divided into two groups (n = 15) according to curing time (10 and 40 seconds). Each group was subdivided into five groups (n = 3) according to the polishing protocol: laboratory polishing with different silicon paper grits (G1:1200) → (G2:2400) → (G3:4000). Chairside polishing was performed using a series of Sof-Lex spiral (G4) and Jiffy Polisher (G5) points. The SR was measured by a surface profilometer. A Vickers indenter was used to test the SH, and a glossmeter was used to determine the SG at 60 degrees. The SR, SG and SH were quantified before and after polishing. A scanning electron microscopy (SEM) evaluation was then performed. The curing time did not affect the surface properties of the BCR (P > 0.05). Significant differences in SR (ranging from 0.1 to 2 μm) and SG (ranging from 20 to 90 GU [gloss unit]) were found according to the type of polishing protocol (P < 0.05). The SH values following different polishing protocols were significantly higher (ranging from 82 to 95 VH [Vickers hardness]) than the polishing values obtained before the polishing protocols (P < 0.05). The tested chairside polishing protocols presented lower SG and higher SR values than the laboratory polishing protocols.

Effect of different polishing techniques on surface roughness and bacterial adhesion of three glass ionomer-based restorative materials: In vitro study.

BackgroundAlthough many reports concluded that polishing of glass ionomers is crucial for smoother surface and limiting the adhesion of cariogenic bacteria, there is no specific surface treatment protocol recommended. A novel material in the same category was released recently claimed to have surface smoothness comparable to resin composite and bacterial adhesion less than other types of glass ionomers. In this study, different polishing systems were tested with three glass ionomers one of them is the novel material to find the most appropriate polishing protocol. Objectives: To evaluate and compare the surface roughness and bacterial adhesion to resin modified glass ionomer, bioactive ionic resin and conventional glass ionomer restorative materials after different polishing protocols in vitro. Material and MethodsThe materials tested includes resin modified glass ionomer, bioactive ionic resin, and conventional glass ionomer. The polishing protocols were divided into four groups: group 1 = (Mylar matrix strips, Control), group 2 = (one-step, PoGo), group 3 = (two-step, Prisma Gloss) and group 4 = (three-step, Sof-Lex). From each material, eleven cylindrical specimens were prepared for each group according to the manufacturers’ instructions. The surface roughness for all specimens was measured using atomic force microscope in tapping mode. the same specimens were subjected to bacterial adhesion testing after being coated with artificial saliva. Data were analyzed with two-way analysis of variance followed by Post hoc multiple comparisons. ResultsThe highest Ra and S. mutans adhesion values were recorded for all materials in two-step group. The lowest Ra and S. mutans adhesion values were seen in one-step and three step groups. ConclusionsOne-step polishing system was more effective and may be preferable for polishing of the three studied glass ionomer-based materials compared to two-step and three-step systems. Key words:Activa bioactive restorative, glass ionomer, surface roughness, bacterial adhesion, surface treatment.

The effect of polishing protocol on surface gloss of different restorative resin composites

Aim The purpose of this in vitro study was to determine the effects of different polishing protocols on the surface gloss (SG) of different commercial dental resin composites (RCs). Material and methods A total of 147 block-shaped specimens (40 mm length × 10 mm width × 2 mm thick) were made from conventional RCs (G-aenial Ant. and Flo X), bulk-fill RC (Filtek Bulk Fill), fluoride-releasing RCs (BEAUTIFIL II, ACTIVA-Restorative) and discontinuous microfiber-reinforced RCs (Alert and everX Flow). Each group was subdivided into seven subgroups (n = 3), according to polishing protocol: Laboratory-machine polishing with different siliconcarbide paper grits (G1: 320) → (G2: 800) → (G3: 1200) → (G4: 2000) → (G5: 4000). Chairside-hand polishing using a series of Sof-Lex spiral (G6) and abrasive polishing points (G7). Glossmeter was used to determine the SG at 60° incidence angle. SG was measured before and after polishing. Three-dimensional (3 D) noncontact optical profilometer and scanning electron microscopy (SEM) analysis were performed. Data were analyzed using ANOVA (p = .05). Results Significant differences in SG (ranged 3–93 GU) were found according to the type of polishing protocol and RC (p < .05). Specimens polished with 4000 grit paper showed the highest SG (93 GU) values among all the groups tested. Conclusions The tested chairside-hand polishing protocols presented lower SG values than laboratory-machine polishing (4000 silicon paper grit) and unpolished surfaces.

Effect of polishing protocols on the surface roughness of polyetheretherketone.

The purpose of this study was to evaluate the influence of various polishing protocols on the surface roughness of polyetheretherketone (PEEK) and identify an effective polishing method of dental prostheses at the chairside. The PEEK specimens were assigned to seven groups with different protocols: no additional polishing (NT); polishing using a rubber point (C); polishing using "silky shine" (S); polishing using "aqua blue paste" (A); protocol C followed by protocol S (CS); protocol C followed by protocol A (CA); and protocol C followed by protocols S and A (CSA). The surface roughness (Sa and Ra) of the polished surfaces was measured. The surface roughness decreased in the following order of groups: NT, C, S, CS, CSA, CA, and A. In Groups C and S, wide deep pits formed by abrasive grains of SiC paper were observed, whereas only fine linear structures were observed on the surface in other groups. With respect to the polishing protocol of PEEK, clinically acceptable surface roughness was obtained using a soft polishing brush and agent for more than 3 min.

Effective Protocol for Daily High-quality Direct Posterior Composite Restorations: Layering and Finishing.

Currently, there is a trend towards simplification of materials and clinical procedures. Simplification and quality can go together if the dentist works with materials and techniques that are well proven in vitro and in vivo. The placement of a high-quality class-1/2 direct posterior composite restoration can be time efficient following a standardized layering protocol and using composite materials that adapt well to the tooth surface and are able to mimic the natural tooth. When these materials are applied in a controlled way, finishing and polishing can also be shortened. In this article, an effective layering and finishing/polishing protocol for medium-sized class-1/2 direct posterior composite restorations is presented. Following the histo-anatomic buildup of natural teeth, dentin must be concave, as opposed to convex enamel. An isochromatic, medium-opaque, highly filled flowable composite is used to replace dentin. Enamel is replaced with a medium-translucent small-particle hybrid composite. Enamel is modelled in an anatomical way, following a successive cusp-by-cusp buildup approach. Clinical experience shows that the combination of both materials used according to this so-called bi-laminar histo-anatomical layering approach results in restorations that blend in very well within the surrounding tooth structure. Following a simplified finishing and polishing protocol, the composite restorations will have a correct contour, seamless margins, and a smooth, glossy surface.

Predictability of Microbial Adhesion to Dental Materials by Roughness Parameters

Microbial adhesion to intraoral biomaterials is associated with surface roughness. For the prevention of oral pathologies, smooth surfaces with little biofilm formation are required. Ideally, appropriate roughness parameters make microbial adhesion predictable. Although a multitude of parameters are available, surface roughness is commonly described by the arithmetical mean roughness value (Ra). The present study investigates whether Ra is the most appropriate roughness parameter in terms of prediction for microbial adhesion to dental biomaterials. After four surface roughness modifications using standardized polishing protocols, zirconia, polymethylmethacrylate, polyetheretherketone, and titanium alloy specimens were characterized by Ra as well as 17 other parameters using confocal microscopy. Specimens of the tested materials were colonized by C. albicans or S. sanguinis for 2 h; the adhesion was measured via luminescence assays and correlated with the roughness parameters. The adhesion of C. albicans showed a tendency to increase with increasing the surface roughness—the adhesion of S. sanguinis showed no such tendency. Although Sa, that is, the arithmetical mean deviation of surface roughness, and Rdc, that is, the profile section height between two material ratios, showed higher correlations with the microbial adhesion than Ra, these differences were not significant. Within the limitations of this in-vitro study, we conclude that Ra is a sufficient roughness parameter in terms of prediction for initial microbial adhesion to dental biomaterials with polished surfaces.

Microbiological and SEM-EDS Evaluation of Titanium Surfaces Exposed to Periodontal Gel: In Vitro Study.

Inflammatory diseases affecting the soft and hard tissues surrounding an implant represent a new challenge in contemporary implant dentistry. Among several methods proposed for the decontamination of titanium surfaces, the administration of topical 14% doxycycline gel seems to be a reliable option. In the present study, we evaluated the microbial effect of 14% doxycycline gel applied on titanium surfaces and exposed to human salivary microbes in anaerobic conditions. We also examined the composition of the exposed surfaces to assess the safe use of periodontal gel on titanium surfaces. Six anatase and six type 5 alloy titanium surfaces were used and divided into two groups: The test group and the positive control group. Both were cultured with human salivary samples in anaerobic conditions. On the test groups, 240 mg of periodontal gel was applied. The microbial assessment was performed with a colony-forming unit (CFU) count and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) to identify the species. The surface integrity was assessed using scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDS). The results demonstrated the microbial efficacy of the 14% doxycycline periodontal gel and its safe use on titanium surfaces. However, the SEM observations revealed the permanence of the gel on the titanium surfaces due to the physical composition of the gel. This permanence needs to be further investigated in vivo and a final polishing protocol on the titanium surface is recommended.

Protocolo de acabamento, texturização e polimento para restaurações diretas em resina composta

O presente relato de caso clínico descreve uma abordagem conservadora para otimização de facetas diretas em resina composta. Para melhoria da anatomia e textura superficial das restaurações antigas, o tratamento baseou-se em um protocolo previsível e reprodutível de acabamento e polimento, o qual garantiu a obtenção de um sorriso equilibrado sem expor a paciente ao ciclo restaurador repetitivo. Inicialmente, a estratégia consistiu na remoção dos excessos de resina, definindo a anatomia primária dos dentes, seguindo a definição dos sulcos verticais e horizontais para mimetizar as características superficiais naturais, proporcionando superfície mais estética e favorável à reflexão de luz. Em adição, o polimento foi conduzido de modo a obter restaurações lisas e brilhantes, que proporcionam maior longevidade aos tratamentos restauradores estéticos.

Surface Topography, Gloss and Flexural Strength of Pressable Ceramic After Finishing-Polishing Protocols.

This study evaluated the effect of different finishing-polishing protocols on surface roughness, gloss, morphology and biaxial flexural strength of pressable fluorapatite glass ceramic. Thirty ceramic discs (12x1 mm) were produced and divided into five groups (n=6): CT: control (glaze); DA: fine grit diamond bur; DG: DA + new glaze layer; DP: DA + felt disk with fine grit diamond paste; DK: DA+ sequential polishing with silicon abrasive instruments, goat hair brush and cotton wheel. The specimens were analyzed for surface roughness (Ra) under profilometry and atomic force microscopy (AFM). Gloss was measured with spectrophotometry and micromorphology with scanning electron microscopy (SEM). Flexural strength was assessed by biaxial flexural strength test. Data were analyzed using one-way ANOVA and Tukey's post hoc test (a=0.05). DK showed the lowest surface roughness values and DA presented the highest in the perfilometer analysis. No significant differences were observed in the AFM for the CT, DG and DK groups, which presented the lower surface roughness; DA and DP had the higher Ra values. The DA, DP and CT showed the lowest surface gloss values, and the reflectance was significantly different from those observed for DK and DG groups. SEM analysis revealed the smoothest surface for DK group, followed by DG and CT groups; DA and DP groups exhibited variable degrees of surface irregularities. No significant differences were observed among groups for the biaxial flexural strength. The polishing protocol used in DK group can be a good alternative for chairside finishing of adjusted pressable fluorapatite glass ceramic surfaces.

The effect of different finishing & polishing protocols on the surface roughness & flexural strength of zirconia bars

IntroductionThe aim of this study is to evaluate the effect of three different finishing and polishing protocols on the surface roughness and flexural strength of tetragonal zirconia. Materials and methods1: Surface roughness; One hundred and five bars of Y-TZP were prepared from Zenostar zirconia blocks (Ivoclar Vivadent). Fifteen bars were distributed into one of seven groups (n = 15/group). Three rotary systems were assessed for finishing and polishing zirconia. After surface preparation the surface roughness was measured using a non-contact profilometer (NPFlex Light interferometer, Bruker Corp., Tucson, AZ). 2: Flexural Strength; Flexural strength of the bars was determined using a three point bending test in a Universal Testing Machine (Instron). Results1: Surface roughness; A significant interaction was demonstrated between grinding condition and polishing kit (P = 0.001). 2: Flexural Strength; a statistically significant difference in flexural strength between groups was seen (p < 0.05). There was no significant interaction effect (P = 0.869). ConclusionsSurface adjustment with dry grinding conditions increased the surface roughness of Y-TZP using the Komet polishing kit compared to wet conditions. Dry grinding lowered the flexural strength compared to wet grinding, irrespective of the kit being used. Achieving a polished surface comparable to that of the control group can be possible by using Brasseler’s zirconia polishing kit under wet grinding conditions.

Effects of different surface finishing protocols for zirconia on surface roughness and bacterial biofilm formation.

PURPOSESurface finishing of a zirconia restoration is essential after clinical adjustment. Herein, we investigated the effects of a surface finishing protocol for monolithic zirconia on final roughness and bacterial adherence.MATERIALS AND METHODSForty-eight disk-shaped monolithic zirconia specimens were fabricated and divided into four groups (n = 12) based on initial surface treatment, finishing, and polishing protocols: diamond bur+polishing bur (DP group), diamond bur+stone grinding bur+polishing bur (DSP group), no diamond bur+polishing bur (NP group), and no diamond bur+stone grinding bur+polishing bur (NSP group). Initial and final surface roughness was measured with a profilometer, and shown using scanning electron microscope. Bacterial adhesion was evaluated by quantifying Streptococcus mutans in the biofilm. Kruskal-Wallis and Mann-Whitney U tests were used to compare results among groups, and two-way analysis of variance was used to evaluate the effects of grinding burs on final roughness (α=.05).RESULTSThe DP group had the highest final Ra value, followed by the DSP, NP, and NSP groups. Use of the stone grinding bur as a coarse-finishing step significantly decreased final Ra values when a diamond bur was used (P<.001). Omission of the stone grinding bur increased biofilm formation on specimen surfaces. Combining a stone grinding bur with silicone polishing burs produced the smallest final biofilm values, regardless of the use of a diamond bur in initial surface treatment.CONCLUSIONCoarse finishing of monolithic zirconia with a stone grinding bur significantly decreased final Ra values and bacterial biofilm formation when surfaces had been roughened by a diamond bur.

Post-CMP Cleaning of InGaAs Surface for the Removal of Nanoparticle Contaminants for Sub-10nm Device Applications

In this study, the development of post-chemical mechanical polishing (CMP) protocols for cleaning abrasive nanoparticles from In0.53Ga0.47As surfaces was systematically analyzed. Abrasive silica nanoparticles (130 and 289 nm) were intentionally deposited onto InGaAs surfaces. Various concentration ratios of chemical etchants such as HCl and H2O2 were used to control material loss and surface oxides of InGaAs. The optimal concentration ratio of the HCl/H2O2 cleaning solution exhibited 40% particle removal efficiency (PRE). Application of megasonic (MS) cleaning improved the PRE to 80%. To prevent particle re-contamination, ammonium dodecyl sulfate (ADS) was used as an anionic surfactant to modify surface charge in the InGaAs substrate. Addition of surfactant further improved the PRE to over 96%. Optimal cleaning of InGaAs surfaces was achieved with a combination of HCl/H2O2, surfactant, and MS.

The effect of polishing protocols on the surface roughness of zirconium oxide

The effect of polishing protocols on the surface roughness of zirconium oxide

The Effect of a Continuous Mechanical Polishing Protocol on Surface Roughness, Biofilm Adhesion, and Color Stability of Acrylic Resin Artificial Teeth.

Acrylic resin properties are susceptible to change over the duration of use, thereby decreasing prosthesis longevity. To make the material less susceptible to the action of external agents such as stain-causing liquids and cleaning solutions, polishing procedures are recommended. A specific mechanical polishing procedure performed regularly was evaluated regarding the biofilm adhesion, surface roughness (Ra), color stability (ΔE), and mass changes in acrylic resin artificial teeth. Sixty artificial teeth divided into two groups (n=30) were immersed in distilled water (WT) and coffee (CF). These groups were then subdivided (n=10) according to the type of polishing procedure administered: no polishing, biweekly polishing (once every 2 weeks) (pol 1), or monthly polishing (once a month) (pol 2), using aluminum oxide paste and a felt polishing wheel attached to an electric motor at a speed of 3000 rpm. Properties were evaluated at baseline and after 4, 8, 12, and 24 months of simulated immersion. At the end, the adhesion of Candida albicans and Streptococcus mutans multispecies biofilm in all groups was assessed. The CF group showed an increased Ra and weight, and a significantly greater ΔE compared to the WT group. The polishing procedure reduced Ra and minimized the stains caused by coffee, without losing mass, with the biweekly regime more effective than the monthly regime. Also, polishing reduced the adhesion of biofilm in the CF groups, again with the biweekly regime the most effective. When performed regularly, the mechanical polishing procedure tested reduces the changes in artificial teeth subjected to immersion in coffee, with the biweekly frequency most effective regarding the properties evaluated.