Comparison of the effects of surface treatments on roughness of two ceramic systems

WOS: 000305284500003PubMed ID: 22506513Objective: The aim of this study was to evaluate the effects of different surface treatments on the surface roughness of lithium disilicate-based core (IPS Empress 2, shade 210, Ivoclar Vivadent, Schaan, Liechtenstein) and feldspathic ceramics (Vita VM9, VITA Zahnfabrik H. Rauter GmbH & Co. KG, Bad Sackingen, Germany). Background data: Er:YAG laser irradiation is expected to be an alternative surface treatment, thus enhances surface roughness of procelains and produces morphological changes. Methods: Fifty lithium disilicate-based core ceramic discs and 50 feldspathic ceramic discs were prepared (diameter, 10 mm; thickness, 1 mm) according to the manufacturers' instructions. All-ceramic discs were polished to standardize, and surface roughness of the discs was evaluated before treatment and serving as controls. Both of two ceramic groups were divided into five groups (n = 10), and the following treatments were applied: (1) sandblasting with aluminum oxide (Al2O3; Group SB); (2) Al2O3 + Er:YAG laser (Group SB-L); (3) Er:YAG laser irradiation (distance, 1 mm; 500 mJ; 20 Hz; 10W; manually, contact handpiece [R 14]) (Group L); (4) 5% hydrofluoric acid etching (Group HF); and (5) Er: YAG laser + 5% hydrofluoric acid (Group HF-L). Surface roughness was evaluated by profilometry, and specimens were then examined with atomic force microscopy. Results: Data were analyzed by Wilcoxon signed rank, Mann-Whitney U, and Kruskal-Wallis tests (alpha = 0.05). The Wilcoxon signed rank test results indicated that surface roughness after sandblasting was significantly different from the surface roughness after laser irradiation and acid etching (p < 0.001). Mann-Whitney U and Kruskal-Wallis test results indicated that groups SB and SB-L had significantly higher mean roughness values (p < 0.05) than those in the other groups. Conclusions: Groups SB and SB-L had rougher surfaces than the groups subjected to the other surface treatment methods. There was no significant difference in surface roughness between the HF acid etching, Er:YAG laser irradiation, and HF and Er:YAG (p < 0.05)

Surface Roughness and Morphologic Changes of Zirconia Following Different Surface Treatments

Objective: The aim of this study was to evaluate the roughness and morphology of zirconia after air abrasion and erbium:yttrium-aluminum-garnet (Er:YAG) laser application of different intensities. Background data: Although surface roughness is important to obtain micromechanical retention, it is unclear which surface treatment is most appropriate for zirconia. Methods: Fifty sintered zirconia specimens were divided into five groups (n = 10). The following treatments were applied: control, Er:YAG laser irradiation with different energy intensities (200, 300, and 400 mJ), and air abrasion with aluminum oxide (Al2O3) particles (110 mu m). Morphologic changes after surface treatments were examined in microscope analyses. Then, the surface roughness (Ra in mu m) of the specimens was evaluated using a surface texture measuring instrument. Roughness data were analyzed using one-way analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) test (p = 0.05). Results: Results of microscope analyses revealed changes in surface morphology after surface treatments, including the formation of rare pits in the 400 mJ laser group and the formation of microretentive grooves in the air abrasion group. According to the results of the statistical analysis, the mean surface roughness value for the air abrasion group was significantly higher than that of the other groups (p 0.05). Conclusions: According to the results of the statistical and microscopic analyses, 400 mJ Er: YAG laser energy or air abrasion can be used to obtain micromechanical retention prior to luting; however, air abrasion is the most effective surface treatment method

Effects of different surface treatments on shear bond strength in two different ceramic systems

WOS: 000323742200003PubMed ID: 22971913The purpose of this study was to evaluate the influence of different surface treatments (sandblasting, acid etching, and laser irradiation) on the shear bond strength of lithium disilicate-based core (IPS Empress 2) and feldspathic ceramics (VITA VM 9). One hundred ceramic discs were divided into two groups of 50 discs each for two ceramic systems: IPS Empress 2 (group I) and VITA VM 9 (group II). Each of the two groups was further divided into five surface treatment groups (ten each) as follows: group SB, sandblasting with alumina particles (50 mu m); group HF, 5 % hydrofluoric acid etching; group L, Er:YAG laser irradiation (distance, 1 mm; 500 mJ; 20 Hz; 10 W; manually, noncontact R14 handpiece); group SB-L, sandblasting + Er:YAG laser; and group HF-L, 5 % hydrofluoric acid + Er:YAG laser. Luting cement (Panavia 2.0) was bonded to the ceramic specimens using Teflon tubes. After 24 h of water storage, a shear bond strength test was performed using a universal testing machine at a crosshead speed of 0.5 mm/min. The data were analyzed with a two-way analysis of variance (ANOVA) and Tukey's honestly significant difference tests (alpha = 0.05). The two-way ANOVA indicated that the shear bond strength was significantly affected by the surface treatment methods (p < 0.05), but there was no significant interaction between the ceramic systems. Group SB-L had the highest mean values for each ceramic system. Sandblasting, followed by Er:YAG laser irradiation, enhanced the bond strength, indicating its potential use as an alternative method. The atomic force microscopic evaluation revealed that group SB had the most distinct sharp peaks among the groups

Mechanical properties of zirconia after different surface treatments and repeated firings

PURPOSE. This study investigated the influence of surface conditioning procedures and repeated firings on monoclinic content and strength of zirconia before cementation. MATERIALS AND METHODS. Sintered bar-shaped zirconia specimens were subjected to no surface treatment (control), air abrasion, Or grinding (n=21). Their roughness was evaluated using a profilometer, and microscope analysis was performed on one specimen of each group. Then, 2 or 10 repeated firings (n=10) were executed, the monoclinic content of specimens was analyzed by X-ray diffraction, and a three-point flexural strength test was performed. Surface roughness values were compared using one-way analysis of variance (ANOVA) and Tukey honestly significant difference (HSD) tests, the monoclinic content values were tested using Kruskal-Wallis and Mahn-Whitney U tests, and the flexural strength values were tested using two-way ANOVA and Tukey HSD tests (P=.05). Spearman's correlation test was performed to define relationships among measured parameters. RESULTS. Surface-treated specimens were rougher than untreated specimens and had a higher monoclinic content (P<.005), and the relationship between roughness and monoclinic content was significant (P<.000). Neither surface treatment nor firing significantly affected the flexural strength, but Weibull analysis showed that for the air-abraded samples the characteristic strength was significantly. lower after the 10th firing than after. the 2nd firing. CONCLUSION. After firing, a negligible amount of monoclinic content remained on the zirconia surfaces, and rougher surfaces had higher monoclinic contents than untreated surfaces. Multiple firings Could be performed if necessary, but the fracture probability could increase after multiple firings for rougher surfaces

Temperature rises during tooth bleaching with different light-curing units

WOS: 000354532700005The aim of this study was to evaluate the influence of three different light-curing units on the temperature rise induced in the pulpal cavity, when bleached with 35% hydrogen peroxide (HP). Forty extracted maxillary central incisors were randomly divided into four groups according to photoactivation procedure (n=10). Whiteness HP (WHP) bleaching agent which contains 35% HP bleach was placed on the facial tooth surface and no photoactivation device was used (control); an blue light-emitting diode (LED, 40s), a diode laser (4W, Continous mode, 20s), and Nd:YAG laser (4W, 60Hz frequency, 20s). Temperature rise in the pulpal chamber was measured with a J-type thermocouple wire that was connected to a data logger before and immediately after each 20-40s application. One tooth of each group was selected for scanning electron microscope analysis. Data were analyzed using one-way ANOVA followed by the Games Howell post hoc test at a preset alpha of 0.05. One-way ANOVA revealed that there was a significant difference among the light-curing units (p<0.05) and between control group and light-curing units (p<0.05). The Nd:YAG induced significantly, which resulted in higher temperature increase than other light-curing units (10.7 degrees C). The LED unit produced the lowest temperature changes (3.2 degrees C) among the light-curing units. The presence of the bleaching gel did not cause a temperature increase in control group (0 degrees C). The results suggested that using light-curing units caused temperature changes in the intrapulpal cavity during tooth bleaching. The use of LED will be more safer for pulpal health when assisted with WHP bleaching gel

Atomic force microscopy investigation of lithium disilicate glass ceramic after various surface treatments

The aim of this study is to evaluate the influence of various surface treatments on the surface roughness of a lithium disilicate glass ceramic. A total of 25 discs of lithium disilicate glass ceramic were prepared. Specimens were divided into five groups: (1) no treatment, (2) air abrasion, (3) acid etching, (4) Nd:YAG laser irradiation and (5) Er:YAG laser irradiation. Digital images from the surfaces were obtained by means of an atomic force microscope in tapping mode. Surface roughness was measured in 10 × 10 µm boxes. Surface roughness data were analysed by one way analysis of variance. The air abrasion group (550±212 nm) had a significantly higher mean surface roughness value than the other groups. The acid etching group (392±157 nm) had a significantly higher mean roughness value than the control group (228±105 nm). Surface roughness of lithium disilicate glass ceramic was not increased by any of the laser irradiation treatments