Effect Of Different Surface Treatments Research Articles

Push-out Bond Strength of Two Fiber Posts in Composite Resin Using Different Types of Silanization.

The aim of this study was to evaluate the effect of different surface treatments and thermocycling (TC) on the push-out bond strength of two brands of glass fiber posts (GFPs) to composite resin. White Post DC (WP) (FGM Dental Group International, Joinville, Santa Catarina, BR) and Exacto (EC) (Angelus, Clinical Research Dental, Londrina, PR, Brazil). GFPs were cleaned with 70% alcohol and divided into five groups, according to the surface treatment (n=15): control (C), without treatment; prehydrolyzed silane (S-pre) (Prosil, FGM Dental Group International); 37% phosphoric acid + prehydrolyzed silane (AcS-pre); Scotchbond Universal Adhesive System (AdU), 3M Oral Care; two-bottle silane (S2B) (Dentsply Sirona Inc). The composite resin was inserted around the posts by using a split matrix. The samples were cut into 1-mm slices. Half of the samples were subjected to the push-out test immediately, and the other half underwent TC before the test. After failure analysis, the data were submitted to three-way analysis of variance (ANOVA) (α=0.05). EC achieved higher bond strength than WP, regardless of TC (p<0.05). Regarding WP, surface treatments (p<0.001) and TC (p<0.001) influenced bonding strength. As for EC without TC, the highest bond strength (p<0.05) was found for C, then AcSpre, S-pre, AdU, and S2B. Application of TC resulted in a statistically higher bond strength values for the EC AcS-pre group (p<0.05), followed by S2B, S-pre, C, and AdU. The WP failures were predominantly cohesive, similar to the EC AdU and EC S2B groups. The other EC groups showed mostly mixed failures. Surface treatment and TC affected the bond strength to composite resin, depending on which post was used. It is important for dentists to understand the effects of different types of silanization on their chosen post.

Surface Treatment and Cementation of Lithium Silicate Ceramics Containing ZrO2.

To evaluate the effect of different surface treatments on the shear bond strength (SBS) of lithium silicate (LS) and lithium disilicate (LD) ceramics, after thermocycling. For SBS test, 72 ceramic blocks (18×14×2 mm) were made (24 blocks from each ceramic material): VITA Suprinity (LSS), Celtra Duo (LSC), and Lithium disilicate (LD). The blocks were polished with sandpaper of increasing grit (#280, #400, #800, and #1200) and embedded in chemically activated acrylic resin. Afterwards, they were randomly divided into 12 groups (6 blocks per group) according to: "Ceramic" (LD, LSC, and LSS) and "Surface treatment" (HFS: hydrofluoric acid + silane; MEP: Monobond Etch & Prime/Ivoclar). From each treated surface ceramic block, four dual-curing resin cement cylinders (RelyX U200, 3M Oral Care) were prepared using a Tygon tube (Ø=3 mm and h=2 mm) and light cured for 40 seconds (1000 mW/cm2) (N=288/n=24). All specimens were submitted to thermocycling (10,000 cycles, 5°C and 55°C, 30 seconds) and then to SBS test at a crosshead speed of 1 mm/min using a 50-kgf load cell. Forty-five additional blocks were made for roughness and SEM analysis. Failure mode was also performed. The data (MPa) were statistically analyzed by oneway analysis of variance (ANOVA), Tukey test (5%), and Weibull analysis. The Ra was analyzed by Kruskal-Wallis and Dunn Test (5%). The other variables were analyzed qualitatively. ANOVA revealed that "surface treatment" was significant for all ceramic materials (p<0.05). The LD-HFS (18.66±3.49), LSC-HFS (16.81±2.62), and LSS-HFS (16.33±3.08) groups had significantly higher SBS than the LD-MEP (7.00±4.2), LSCMEP (14.12±3.51), and LSS-MEP (13.87±2.52) groups. Complete adhesive failures at the cement-dentin interface were more frequent. Weibull modulus was superior for the LD-HFS (6.22), LSC-HFS (8.8), and LSS-HFS (7.4) groups. HF followed by silanization is the most suitable surface treatment for the cementation of LS and LD glass ceramics.

A comparative study of the effect of different surface treatments on polymeric substrates

In this work, we investigated the effect of three surface treatments on the properties of polymethyl methacrylate (PMMA) and polycarbonate (PC). The treatments consisted of ultraviolet-ozone, sputter etching and oxygen plasma. Their effect on the adhesion between a vacuum deposited TiO2 coating and the substrate were also assessed by cross-cut test. Detailed characterization of the optical properties, surface wettability, morphology and the chemical composition of the surface after the treatments was performed for the test samples. Reference samples without any surface treatment were also used for comparison purposes. Optical transmittance of the samples was not significantly altered by the surface treatments. Only the presence of the coating led to an increase of the system refractive index and to a small decrease of the light transmittance. All surface treatments lead to an increase of oxygen species in polymer surface, which rise the wettability. In particular, the ultraviolet-ozone treatment shows a higher change in the oxygen/carbon ratio, resulting however in the weakest adhesion between the coating and substrate, due to the generation of low molecular weight compounds weakly bonded to the surface. Furthermore, regardless of the surface treatment employed, the PMMA substrate presented lower film adhesion than PC.

Effect of surface treatment and luting agent type on shear bond strength of titanium to ceramic materials.

PURPOSEThis study aimed to compare the effect of different surface treatments and luting agent types on the shear bond strength of two ceramics to commercially pure titanium (Cp Ti).MATERIALS AND METHODSA total of 160 Cp Ti specimens were divided into 4 subgroups (n = 40) according to surface treatments received (control, 50 µm airborne-particle abrasion, 110 µm airborne-particle abrasion, and tribochemical coating). The cementation surfaces of titanium and all-ceramic specimens were treated with a universal primer. Two cubic all-ceramic discs (lithium disilicate ceramic (LDC) and zirconia-reinforced lithium silicate ceramic (ZLC)) were cemented to titanium using two types of resin-based luting agents: self-cure and dual-cure (n = 10). After cementation, all specimens were subjected to 5000 cycles of thermal aging. A shear bond strength (SBS) test was conducted, and the failure mode was determined using a scanning electron microscope. Data were analyzed using three-way ANOVA, and the Tukey-HSD test was used for post hoc comparisons (P < .05).RESULTSSignificant differences were found among the groups based on surface treatment, resin-based luting agent, and ceramic type (P < .05). Among the surface treatments, 50 µm air-abrasion showed the highest SBS, while the control group showed the lowest. SBS was higher for dual-cure resin-based luting agent than self-cure luting agent. ZLC showed better SBS values than LDC.CONCLUSIONThe cementation of ZLC with dual-cure resin-based luting agent showed better bonding effectiveness to commercially pure titanium treated with 50 µm airborne-particle abrasion.

Effect of surface treatment, ferrule height, and luting agent type on pull-out bond strength of monolithic zirconia endocrowns.

To evaluate the effect of different surface treatments, ferrule heights, and luting agents on the pull-out bond strength (PBS) of computer-aided design/computer-aided manufacturing (CAD-CAM) monolithic endocrowns. After endodontic treatment and preparation for two endocrown designs (ferrule height 0 mm or 2 mm), CAD-CAM monolithic zirconia endocrowns were fabricated for 80 mandibular molars. Each endocrown design group was then divided on the basis of surface treatment into two groups: half were air-abraded and half were air-abraded/laser-irradiated. Then, all treated groups were further divided into two subgroups (n = 10) and cemented to teeth with either a 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-containing resin luting agent (Panavia SA) or a combination of MDP-containing primer and MDP-free resin luting agent (Monobond Plus/Multilink Automix). PBS was measured with a universal test machine after simulated chewing and thermocycling. Three-way ANOVA and the post-hoc Bonferroni test were used for statistical analysis. PBS was significantly associated with type of surface treatment, type of luting agent, and ferrule height. Air-abraded/laser-irradiated endocrowns with a 2-mm ferrule that were cemented with Monobond Plus/Multilink Automix had the highest PBS (P < 0.05). Surface treatment with air abrasion/laser irradiation, presence of a ferrule, and priming with an MDP-containing primer increased the PBS of monolithic zirconia endocrowns.

Effects of surface modification techniques on zirconia substrates and their effect on bonding to dual cure resin cement - An in- vitro study.

This study aims to evaluate the effect of different surface treatments of monolithic zirconia on the bond strength of resin to zirconia and, to explore alternative methods to improve this bonding. In-Vitro study. Fifty rectangular sintered blocks of Yttria-stabilized Tetragonal Zirconia Polycrystal ceramics of dimensions were milled and sintered. These specimens were further divided into five groups (control, air abrasion, etching with primer application, air abrasion with primer application and novel glass infiltrated zirconia surface group), containing 10 samples each. The specimens were analyzed for surface roughness, tensile bond strength to resin cements, and adhesive and cohesive mode of failures. ANOVA and Post-Hoc Tukey test was perform to evaluate the significant differences in the mean values of the groups. Air-abraded samples showed the highest surface roughness (4.95 ± 0.65) (P < 0.05). The group with air abrasion followed by primer application showed the highest tensile bond strength (7.12 ± 0.69) (P < 0.05). The lowest surface roughness (0.638 ± 0.8093) and tensile bond strength (2.03 ± 0.58) was seen in samples that were subjected to etchant treatment followed by application of methacryloyloxydecyl di-hydrogen phosphate (MDP) primer. The changes in comparison to the control group were statistically insignificant (P > 0.05). Except Groups A (control) and C (etchant followed by primer), all other groups showed a cohesive failure. Air abrasion of the zirconia surface with 50 μm alumina particles increases the surface roughness without damaging the surface. Air abrasion followed by MDP primer application is the recommended method of surface treatment to achieve superior bonding. Glass infiltration also showed promising results in terms of tensile bond strength.

Comparative evaluation of different surface treatments of the salivary contaminated dentin on the shear bond strength of self-etch adhesives: An in vitro study.

Aims and Objectives:This study aimed to evaluate and compare the effect of different surface treatments of the salivary contaminated dentin on the shear bond strength of one-step self-etch adhesives.Materials and Methods:The coronal buccal surfaces of 50 human mandibular molars were ground to expose dentin. The specimens were randomly divided into five groups. Ten teeth were left uncontaminated and served as control group. Rest of the teeth were then divided based on the decontamination method used as follows: Group II (no decontamination done), Group III (decontamination with rinsing), and Group IV (decontamination with etching), Group V (decontamination with ethanol). Composite resin cylinders of 4 mm diameter and 4 mm length were fabricated on the surfaces. Shear bond strength testing was done in a universal testing machine, and the data were subjected to a one-way analysis of variance and KruskalWallis test. Intergroup comparison was made using MannWhitney U-test.Results:The highest bond strength was seen in Group 1, followed by and least in Group II. The difference was found to be statistically significant among all the groups. Group II and Group IV showed lower shear bond strength than Group I (control) and Group III (P < 0.05). The intergroup comparison shows significant differences between Group I with all the other groups.Conclusion:It was concluded that the use of decontaminant improved the bond strength to salivary contaminated dentin in self-etch adhesives.

The effect of different surface treatments to reduce surface roughness before PVD coatings

Titanium and its compounds are used in aerospace, automotive, and chemical but currently it's considerably used in biomedical usages due to its excellent combination of low viscosity, high strength to weight rate, high erosion resistance, and biocompatibility, still, the main limit is poor tribological parcels therefore it cannot be successfully used. Wide range of face treatments disposition of shells similar as scraping and melting of face and cumulative processes similar as plating. For essence, face variations are plating or sheeting processes. There are different types of face coatings charging, electrochemical coatings, vapor deposit, conversion coatings, and thermal spraying among them PVD is vapor deposit which the coatings are hard and thin film. In PVD coatings Nitrides and carbide coatings are classified. In which nitride coatings TiN, TiAlN, and duplex TiAlN and drum were deposited on a substrate (Ti6Al4V). But for deposit, the face roughness should be 0.08 µm. Thin hard coatings have good wear and tear resistance only when they've good adhesion and certain face roughness. To reduce face roughness different face treatments are acclimated similar as shot firing, sandblasting, drawing, ray figure, grinding and polishing, etc. Sandblasting was done but the face roughness didn't drop to 0.08 µm. so required face roughness was attained by grinding and polishing with sandpaper, and it was diamond polished

Bond strength of cosmetic ceramic to zirconia: Effect of different surface treatments, A Systematic Review

Bond strength of cosmetic ceramic to zirconia: Effect of different surface treatments, A Systematic Review

Effect of different surface treatments on the bond strength between cobalt-chromium (Co-Cr) framework infrastructure and veneer resin or artificial tooth

Effect of different surface treatments on the bond strength between cobalt-chromium (Co-Cr) framework infrastructure and veneer resin or artificial tooth

The Influence of Combined Surface Treatmentsusing Plasma of Argon, Er:Yag Laser and Sandblasting on the Shear Bond Strength of Zirconia Core to the Veneering Ceramic – In Vitro Study

Background: Success of zirconia-based prosthesis is greatly affected by ceramic chipping and delamination due to poor bonding between zirconia framework and veneering ceramic. This study uses combination of surface treatment with Non-thermal Argon Plasma to evaluate its effect on Shear Bond Strength (SBS). Objective: The study aimed to evaluate the effect of different surface treatment using sandblasting, argon plasma, Er:YAG laser and its combination on SBS of zirconia to veneering ceramic. Material and Method: 150 milled and sintered zirconia blocks (10mm x 18mm) were subjected to various surface treatments and were randomly divided into five groups according to the surface treatment methods namely. Group 1: Argon plasma(220 V,100W and constant gas pressure 1 kg/cm2 and gas flow 8.5L/min) + Liner (E max ceram zirliner), Group 2: Atmospheric pressure argon plasma, Group 3: Sandblasting, Group 4: Sandblasting + Laser ablation ( Er:YAG ; 300mJ/pulse energy, frequency-10Hz ) + Argon plasma and Group 5: Sandblasting + Argon plasma. Specimens were subjected to shear bond strength test by a universal testing machine with a crosshead speed of 1 mm/min. The data were analysed with one-way ANOVA and Bonferoni test for multiple comparisons tests (α=0.05). Result: Highest shear bond strength value was obtained for Group 4 followed by Group 5, Group 3, Group 2 with least value obtained for Group 1. Conclusion: This study shows that sandblasting + Er:YAG + Argon plasma showed higher shear bond strength when compared to other groups.

Effects of Boriding, Nitrocarburizing, Nitriding and Post-oxidation Treatments on The Tribological Properties of DIN 32CrMoV12-10 Steel

In this study, the effect of different surface treatments was investigated to improve the friction and wear properties of DIN 32CrMoV12-10 steel. For this purpose, chrome plating, boriding, nitrocarburizing+oxidation, nitriding+oxidation processes were applied to the samples prepared from DIN 32CrMoV12-10 steel. After the procedures, the structural, morphological and mechanical properties of the samples were determined by XRD, SEM, hardness measurement device and profilometer. In order to determine the tribological properties of the samples, pin-on-flat wear tests were carried out. It was observed that a chromium layer was formed on the surface of the material after chrome plating. In boronized samples, it was observed that a boron layer was formed on the surface of the material and a diffusion layer was formed below it. The formed layers contain Fe2B and FeB phases. In nitrocarburized+oxidized and nitrided+oxidized samples, it was observed that the oxide layer on the material surface, a white layer just below it and a diffusion zone extending to the inner parts of the material were formed. The oxide layer formed on the surface consists of Fe2O3 and Fe3O4 phases, while the white layer and diffusion layers consist of ε-Fe2-3N and γ'-Fe4N phases. Due to the increased plastic deformation resistance with oxide layers, hard nitride phases and diffusion layers, the highest wear resistance was obtained from nitrocarburized+oxidized and nitrided+oxidized samples.

Surface Characterisation of Dental Resin Composites Related to Conditioning and Finishing.

Due to the little information related to surface processing and conditioning of resin matrix ceramic materials previous glazing, the main purpose of this in vitro study was to investigate the effect of different surface treatments on the surface morphology of different resin composite materials. Five types of resin composite CAD-CAM materials: a resin composite ceramic Vita Enamic (E) and four types of nanoparticle-filled resins, like Lava Ultimate (L), Cerasmart (C), Shofu HC (S), Hyramic (H) were taken into consideration. Specimens received the following surface treatment protocols: conventional polishing [p], polishing and glazing [pg], conditioning with CoJet [c], conditioning with CoJet and glazing [cg], sandblasting [s], sandblasting and glazing [sg], etching [e], etching and glazing [eg]. Surface roughness was analyzed for all samples and nanosurface topographic characterization was made by Atomic Force Microscopy. The highest roughness was registered for sandblasted surfaces [s], followed by tribochemical silica airborne particle abrasion [c], and etching [e]. A very strong correlated conditioning behavior of resin nanoceramic materials, like L, C and S samples was found. The microroughness decreased thus [s] > [c] > [e]. These are moderate correlated with H, and are moderate negative correlated to E, where e is more efficient. Three-dimensional images indicated visible grain boundaries after conditioning, for all materials. After polishing and glazing, surfaces became smoother. For all tested conditioning and finishing methods, surface roughness values were within clinically acceptable limits. Finishing by polishing was proved to be a good choice for all materials taken into consideration, polishing and glazing likewise, excepting Hyramic. For Enamic and Shofu HC sandblasting or tribochemical conditioning and glazing and for Hyramic polishing and glazing are not the best options, related to nanoroughness values. Referring to the nanosurface topography, for Enamic, Cerasmart and Hyramic, glazing would be the method of choice, associated with the adequate conditioning method for each material.

Effect of Different Surface Treatments and Two Porcelain Repair Systems on the Shear Bond Strength of Composite to Zirconia

Effect of Different Surface Treatments and Two Porcelain Repair Systems on the Shear Bond Strength of Composite to Zirconia

Effect of Different Surface Treatments of Glass Fiber Posts on their Surface Roughness and Flexure Properties

AIM: This study aimed to assess the effect of different surface treatments on the surface roughness and flexure properties of glass fiber posts “GFPs.” MATERIALS AND METHODS: A total of 40 GFPs were divided into four groups (n = 10): GC – no surface treatment (control), GSB – sandblasted, GHF – hydrofluoric acid etched, and GL – Er: YAG laser irradiated. Surface roughness was detected using surface profilometer and the 3-points bending flexural test measured flexural strength and elastic modulus. RESULTS: GSB showed the highest mean roughness followed by GHF, then GL, while GC had lowest roughness mean value. The 3 points bending test results were calculated and recorded, GSB exhibited the highest flexure stress (MPa) compared to GHF and GL. Modulus of elasticity (GPa) showed significant differences between the tested groups, GSB showed the highest modulus of elasticity compared to GHF and GL, while GC showed insignificant differences with all tested groups. CONCLUSION: Different surface treatments postulated in this study showed alternations of GFPs surfaces without jeopardizing the mechanical properties of GFPs.

Comparative Effect of Different Surface Treatments on the Shear Bond Strength of Two Types of Artificial Teeth Bonded To Two Types of Denture Base Resins.

This in vitro study aims to assess the impact of various surface treatments on the shear bond strength (SBS) of two types of artificial teeth and denture base resins (DBRs). Two types of DBRs (CAD/CAM-milled and heat-polymerized) and two types of denture teeth (acrylic and composite) were investigated. Teeth were cut into slices (5 × 5 × 2 mm) and divided according to surface treatment into four subgroups (n = 10): no treatment (control), air abrasion (Alumina-blasting; AB), bur roughening, and dichloromethane (DCM) subgroups. According to manufacturer recommendations, the treated tooth slices were bonded to the acrylic disk of DBRs. The SBS test was performed using a universal testing machine. ANOVA was used for results analysis followed by Tukey's post hoc tests (α = 0.05). DCM and AB increased the SBS of acrylic teeth to heat-polymerized DBR compared with other groups (p < 0.001). All surface treatments showed no significant difference in CAD/CAM DBR with acrylic teeth (p = 0.059; AB, p = 0.319; bur roughening, p = 0.895; DCM), while there was a significant decrease in SBS with composite teeth (p ˂ 0.001). Between teeth, acrylic teeth showed a statistically significant increase in SBS compared to composite teeth (p < 0.001). AB and DCM application improved the SBS for acrylic teeth with the heat-polymerized DBR when compared with the untreated group, but none of the surface treatment agents showed significant improvement with CAD/CAM DBR. All surface treatment agents reduced the SBS for composite teeth with CAD/CAM DBR while AB only increased the SBS with heat-polymerized DBR.

The Effect of different Surface Treatments on Shear Bond Strength of Cubic Zirconia

Statement of the problem: The conventional methods of adhesive bonding used in silica containing ceramics cannot be used for bonding of zirconia due to absence of silica. Objective: The study was designed to evaluate the effect of different surface treatments on the shear bond strength of cubic zirconia before and after aging. Materials and Methods: A total of 56 cubic zirconia plates with dimensions (10mm length and 10mm width and 2mm thickness) were divided into four groups according to surface treatment (Group 1;No treatment n=14, Group 2; Air abrasion 50µm AL2O3 particles for 15 seconds n=14, Group 3; CO2 laser at 10W for 10 seconds n=14, Group 4; CO2 laser at 20W for 10 seconds n=14), then each group was subdivided into 2 subgroups which are(Group a: before aging) and (Group b: after aging) n=7. All specimens were cemented with MDP resin cement (Panavia SA cement plus) and stored in a distilled water for 24 hours. Then shear bond strength test (SBS) was assessed in MPa with a universal testing machine before and after thermocycling. Results: The results of this study clearly showed that the samples treated with CO2 laser groups at 20 W have the highest shear bond strength of resin cement to zirconia ceramic followed by CO2 at 10 W followed by sandblasting group and the control group showed the least shear bond strength. Conclusion: The application of CO2 laser surface treatment enhanced the shear bond strength of ultra-translucent zirconia to MDP containing resin cement.

Effect of Different Surface Treatments on the Bond Strength of the Hybrid Ceramic Characterization Layer.

Using the microshear bond strength (µSBS) test, this study investigated the bond strength between a hybrid ceramic and the extrinsic characterization layer after different ceramic surface treatments. Hybrid ceramic blocks (Vita Enamic, Vita Zahnfabrik) were sectioned and randomly divided into 4 groups (N = 120) according to the surface treatment and aging (n = 15): P: polishing; E: acid etching with HF; A: aluminum oxide blasting; S: self-etching ceramic primer. The specimens were silanized, then cylinders of light-curing characterization material (Vita Enamic Stain, 1.6 mm diameter x 2 mm height) were fabricated, followed by glazing. The specimens were subsequently immersed in distilled water for 24 h and subjected to the µSBS test using a universal testing machine (load cell 0.5 mm/min, 50 kgf) or tested after thermocycling for 10,000 cycles in water (5°C-55°C). After treatment, the specimen surfaces were analyzed using SEM, with failure types defined as adhesive, predominantly adhesive, or cohesive. The data were analyzed by two-way ANOVA followed by Tukey's test (p < 0.05). The most frequent failure type was predominantly adhesive between ceramic and the characterization layer. There were statistically significant differences between the surface treatments (p < 0.05). Thermocycling did not lead to statistically signifcant different results (p > 0.05). For groups P and A, a sharp decrease in SBS was observed. The absence of surface treatment drastically reduced the microshear bond strength between the ceramic and the characterization layer. Conditioning with 5% hydrofluoric acid for 60 s is the most suitable treatment for adhesion of the characterization layer to hybrid ceramic.

Impact of Different Surface Treatments on Zirconia Strength

Background: Intraoral polishing of zirconia surfaces had led to a significant increase in the surface smoothness and flexural strength of zirconia after surface modifications in the try-in procedure; this is a straightforward procedure and does not need any laboratory interventions. Objectives: The aim of this study was to evaluate the effect of different surface treatments on yttrium-stabilized zirconia restorations. Materials and Methods: In this study, 36 disk-shaped specimens from zirconia blocks were milled using a CAD-CAM machine with 12 mm diameter and 1.4 mm thickness for 27 disks; however, 12 mm diameter and 1.2 mm thickness were used for nine disks as a control group. They were sintered and glazed according to the manufacturer's instructions. The control group (GA) remained untouched, whereas the other specimens were ground with a diamond rotary instrument. The final dimension was 12 mm in diameter and 1.2 ± 0.1 mm in thickness. The disks were divided into three groups: Grinded group (GB) without any additional surface treatment; reglazed group (GC) by adding glaze material; and polished group (GD), polished with an intraoral polishing kit. The specimens were subjected to a biaxial flexural strength (BFS) test. Data were statistically analyzed using one-way analysis of variance and least significant difference (LSD) significant difference tests (a = 0.05). Results: Descriptive statistics shows that the highest BFS was recorded for the GD followed by GB, and both GA and GC show nearly similar values. The LSD tests revealed that there was a statistically significant difference between GD and GA (P &lt; 0.05), GD had significantly increased the BFS value after being polished compared with other groups, and there was a statistically significant difference between GB and GA (P &lt; 0.05). However, there was no statistically significant difference between GC and GA (P = 0.494). Conclusion: Grinding and polishing techniques significantly increased the flexural strength of full-contoured zirconia, whereas reglazing significantly decreased it.

Estimation of the autoclave and different surface treatments on microleakage between soft liner and heat-cured acrylic

Objective: The present study was oriented to estimate the effect of different surface treatments on the microleakage between the soft liner and acrylic with and without the use of autoclave as disinfection method. Material and Methods: Sixty samples were split into two groups: the autoclaved groups and non-autoclaved groups. Each one subdivided into three groups: first one without any treatments as a control group; in the second group surface of the samples were treated with CO2 laser (10.6 nm wavelength for 15 seconds), and in the third group the surface was treated with sandblasting. All the samples exposed to thermocycling, then the microleakage test was evaluated by gauging dye penetration depth between the soft liner and acrylic disc using a digital microscope. Data analyzed statistically by One-way ANOVA and Tukey's post-hoc tests. In addition, t-test was used for comparison between two groups . Results: The maximum mean values for the microleakage were observed in the untreated group (control) followed by the group treated by CO2 laser and the lowest mean value of microleakage was related to the third group for both non-autoclaved and autoclaved groups with significant differences among them. In addition, depending on the use of autoclave, there was non-significant in all studied groups. Conclusions: There was a decrease in the microleakage when the surface treated with CO2 laser and sandblast. The use of autoclave did not badly change the microleakage between the soft liner and denture base. Keywords Microleakage; Soft liner; Autoclave; CO2 laser; Sandblast.