PURPOSETopographic analysis of treated ceramics provides qualitative information regarding the surface texture affecting the micromechanical retention and locking of resin-ceramics. This study aims to compare the surface microstructure following different surface treatments of feldspathic porcelain.MATERIALS AND METHODSThis in-vitro study was conducted on 72 porcelain discs randomly divided into 12 groups (n=6). In 9 groups, feldspathic surfaces were subjected to sandblasting at 2, 3 or 4 bar pressure for 5, 10 or 15 seconds with 50 µm alumina particles at a 5 mm distance. In group 10, 9.5% hydrofluoric acid (HF) gel was applied for 120 seconds. In group 11, specimens were sandblasted at 3 bar pressure for 10 seconds and then conditioned with HF. In group 12, specimens were first treated with HF and then sandblasted at 3 bar pressure for 10 seconds. All specimens were then evaluated under scanning electron microscopy (SEM) at different magnifications.RESULTSSEM images of HF treated specimens revealed deep porosities of variable sizes; whereas, the sandblasted surfaces were more homogenous and had sharper peaks. Increasing the pressure and duration of sandblasting increased the surface roughness. SEM images of the two combined techniques showed that in group 11 (sandblasted first), HF caused deeper porosities; whereas in group 12 (treated with HF first) sandblasting caused irregularities with less homogeneity.CONCLUSIONAll surface treatments increased the surface area and caused porous surfaces. In groups subjected to HF, the porosities were deeper than those in sandblasted only groups.
Increasing the sandblasting pressure increased the surface roughness of feldspathic porcelain but no difference in bond strength occurred.
Background and Aim: High consumption of carbonated diet soda is the most common etiologic factor for dental erosion. The purpose of this study was to evaluate the microhardness of the enamel surface eroded by cola after treatment with Remin Pro and neutral sodium fluoride. Materials and Methods: This in vitro experimental study was performed on 20 extracted premolars with no corrosion, abrasion, crack or hypocalcification. To properly evaluate the microhardness, the buccal surface of samples was polished with sandpaper and then the teeth were immersed in acidic drinks to achieve demineralization. Next, the microhardness was measured at three new points and the samples were randomly divided into two groups for application of neutral sodium fluoride and Ramin Pro. Duration of treatment was in accord with the manufacturer's instructions and the microhardness of the samples was measured again. Results: Significant differences were found between the two groups after the treatment, and the fluoride group showed higher microhardness (P=0.04). Also, the microhardness value was significantly different at the three time points (P<0.001). Conclusion: Cola decreased the enamel microhardness while Remin Pro and neutral sodium fluoride increased the microhardness of enamel. Neutral sodium fluoride showed better remineralizing effect on enamel microhardness.
Background and Aim: White spot lesions (WSLs) are common occurrence following orthodontic treatment, this study sought to compare the remineralizing potential of fluoride, MI Paste Plus (CPP-ACP-F) and Remin Pro for treatment of WSLs. Materials and Methods: This in vitro study was conducted on 56 sound human premolars that extracted for orthodontic purposes. Teeth were cleaned and their roots were cut, then the crowns were mounted in acrylic resin. Teeth surfaces were coated with nail varnish except for a 3×4mm window on the buccal surface. In order to create WSLs, all samples were immersed in demineralizing solution for 10 days. After surface hardness was measured using a Vickers microhardness tester, teeth were randomly divided into four groups. In control group (group 1) no remineralizing agent was used while, groups 2 to 4, were treated with0.05% sodium fluoride (NaF), MI Paste Plus, and Remin Pro paste respectively, for five minutes every 12hours. After each treatment, specimens were immersed in freshly prepared artificial saliva. At the end of 28 days, surface microhardness was measured again and changes were statistically analyzed using analysis of covariance (ANCOVA). Results: The mean changes in surface microhardness of MI Paste Plus, NaF and Remin Pro groups was significantly higher than control group (P˂0.001, P˂0.001 and P0.046 respectively). Conclusion: MI Paste Plus, 0.05% NaF mouthwash, and to a lesser extent Remin Pro were efficient for treatment of WSLs comparing to the artificial saliva.
Background Esthetic dental restorations have gained increasing popularity. The surface of restorations should be smooth enough to achieve maximum esthetics and prevent the adhesion of microorganisms and food particles. This study aimed to assess the surface roughness and color change of composite specimens following airflow usage. Methods In this in vitro, experimental study, 30 Tokuyama composite discs were fabricated and randomly divided into three groups (n = 10) for the use of airflow with calcium carbonate/bicarbonate powder and conventional polishing with FlexiDisc. The surface roughness of the specimens was measured by profilometry while the color change was assessed by measuring the L*, a* and b* color parameters using spectrophotometry before polishing (T1). The composite specimens were then polished for stain removal, and their surface roughness as well as color parameters were remeasured after polishing (T2). Paired t-test and Tukey’s test were applied for within-group and between-group comparisons. Results Significant differences were noted in roughness average (Ra) between airflow with calcium carbonate (0.251 ± 0.014 μm) and airflow with sodium bicarbonate (0.421 ± 0.208 μm), and between airflow with sodium bicarbonate and FlexiDisc (0.207 ± 0.076 μm) groups after polishing (P < 0.05). Regarding the correlation of change in surface roughness and color parameters at T1 and T2, an inverse correlation was noted between the change in surface roughness and all color parameters except for L*. In other words, reduction in surface roughness decreased the a* and b* color parameters. Conclusions Within the limitations of this study, the results showed that the airflow device used in this study had no significant difference with conventional polishing in terms of reduction in surface roughness and staining. Considering the cost and maintenance of the airflow device, it is not suggested as a suitable alternative to the conventional polishing procedures. Trial Registration Number: This study does not involve human subjects.
Background: Esthetic dental restorations have gained increasing popularity. The restoration surface should be smooth enough to prevent adhesion of microorganisms and food particles, and achieve maximum esthetics. This study aimed to assess the surface roughness and color change of composite specimens following the use of an airflow device. Methods: In this in vitro, experimental study, 30 Tokuyama composite discs were fabricated and randomly divided into three groups (n=10) for the use of airflow with calcium carbonate powder, airflow with sodium bicarbonate powder, and conventional polishing with FlexiDisc. The surface roughness of specimens was measured by profilometry while the color change was evaluated by measuring the L*, a* and b* color parameters by spectrophotometry before polishing (T1). The composite specimens were then polished for stain removal and their surface roughness and color parameters were measured again after polishing (T2). Paired t-test and Tukey’s test were applied for within-group and between-group comparisons.Results: Significant differences were noted in Ra (the roughness average pf surface) between airflow with calcium carbonate (0.251 ± 0.014 µm) and airflow with sodium bicarbonate (0.421 ± 0.208 µm), and also between airflow with sodium bicarbonate and FlexiDisc (0.207 ± 0.076 µm) groups after polishing (P<0.05). Regarding the correlation of change in surface roughness and color parameters at T1 and T2, an inverse correlation was noted between the change in surface roughness and all color parameters except for L*. In other words, increasing the surface roughness difference (surface smoothing), decreased the a* and b* color parameters. Conclusions: Within the limitations of this study, the results showed that the airflow device used in this study had no significant difference with the conventional polishing in terms of reduction in surface roughness and staining. Considering the cost and maintenance of the airflow device, it is not suggested as a suitable alternative to the conventional polishing procedures. Trial Registration Number: This is not a human subject research.
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