scholarly journals Influence of Low-pH Beverages on the Two-Body Wear of CAD/CAM Monolithic Materials

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2915
Author(s):  
Nicola Scotti ◽  
Andrei Ionescu ◽  
Allegra Comba ◽  
Andrea Baldi ◽  
Eugenio Brambilla ◽  
...  

The aim of this in vitro study is to evaluate the effect of different acidic media on volumetric wear and surface roughness of CAD/CAM monolithic materials. Forty-eight rectangular specimens were prepared using different CAD/CAM monolithic materials: nanohybrid composite (Grandio Blocks, Voco), resin-based composite (Cerasmart, GC), lithium disilicate (E-Max, Ivoclar), and high-translucency zirconia (Katana STML, Kuraray Noritake). After storage in distilled water at 37 °C for two days, the specimens were tested using a chewing machine with a stainless-steel ball as an antagonist (49N loads, 250,000 cycles). Testing was performed using distilled water, Coca-Cola, and Red Bull as abrasive media. Wear and surface roughness analyses of the CAD/CAM materials were performed using a 3D profilometer and analyzed with two-way analysis of variance and post hoc pairwise comparison procedures. Worn surfaces were examined using scanning electron microscopy. Resin-based materials suffered higher volumetric wear than ceramics (p = 0.00001). Water induced significantly less volumetric wear than the other tested solutions (p = 0.0014), independent of the material tested. High-translucency zirconia showed less surface roughness than all the other materials tested. The selection of monolithic CAD/CAM materials to restore worn dentition due to erosive processes could impact restorative therapy stability over time. Resin-based materials seem to be more influenced by the acidic environment when subjected to a two-body wear test.

2019 ◽  
Vol 56 (3) ◽  
pp. 583-567
Author(s):  
Csaba Dudas ◽  
Melinda Szekely ◽  
Maria Henrietta Gabor ◽  
Laszlo Jakab Farkas ◽  
Kinga Dorner ◽  
...  

Changes in the surface roughness of dental restorative materials after tooth brushing are inevitable. The abrasion is known to increase the possibility of dental plaque accumulation which is responsible for several pathologies of the oral cavity. The aim of this in vitro study was to evaluate the changes of surface roughness of microhybrid composite materials produced by different toothbrushes with and without toothpaste. Forty-eight specimens of two composite materials (Charisma and Super-Cor) were prepared using a silicone template according to the manufacturer�s instructions. Each sample was brushed for eight hours. Each group of specimens was divided in two subgroups: half of the samples were brushed using only distilled water and the other half with a mixture of distilled water and toothpaste (Colgate Total; ratio 1:1). The average roughness value (Ra) of surfaces were measured with profilometer three times: the initial measurement was performed before starting the toothbrush simulation, the second was after 4 hours and the third was after 8 hours of brushing. Three different bristle stiffness toothbrush heads were used (medium sensitive, medium and soft). After collecting all numerical data one-way ANOVA and Friedman tests were performed for statistical analysis. All examined microhybrid composites exhibited changes in surface roughness after the toothbrush simulation. The simulation of toothbrushing without toothpaste, only with water as cleaning substrate, showed at every measurement the lowest values of roughness in all three toothbrush heads. Significantly increase of mean Ra values were observed in both tested composite samples when medium and soft toothbrushes with toothpaste were used. The surface roughness changes of tested microhybrid composites depend on the brushing procedure. The toothpaste has a much greater effect on the abrasion than the type of toothbrush.


2017 ◽  
Vol 18 (8) ◽  
pp. 679-682
Author(s):  
Nitin Gautam ◽  
Aditi Sharma ◽  
Unjum Bashir ◽  
Sisir Rapolu ◽  
Nallamilli Mamatha ◽  
...  

ABSTRACT Aim This study was undertaken to study the effect of three most commonly used dentifrices for denture cleaning and to find out any positive association between number of strokes by toothbrush and surface roughness of acrylic resin. Materials and methods About 40 acrylic rectangular blocks with high finish were polished until surface roughness was calculated as 0 µm. The materials tested were distilled water as a control group, Patanjali Dant Kanti, Colgate Total Cream, and Cleansodent as dentifrices. Stroking was done with dentifrices, and surface roughness readings were recorded at 1,000, 9,000, and 18,000 strokes. Results Patanjali Dant Kanti was found to have maximum abrasive potential followed by Colgate Total Cream, followed by Cleansodent and least by distilled water. Conclusion Surface roughness was found to be directly proportional to the type, size, and fineness of the abrasive component used; the professional denture cleanser (Cleansodent) has less abrasive potential than the regular toothpastes. Among those tested, the highest abrasive potential was found in Patanjali Dant Kanti and lowest by Cleansodent (denture cleanser). Clinical significance The patient as well as dentist should choose the dentifrice with utmost care noting the size and type of abrasives used. Washing the dentures normally with water without toothbrush daily and cleaning of dentures once in 10 to 15 days with a soft toothbrush and professional denture cleanser should be the line of maintenance of dentures. How to cite this article Gautam N, Sharma A, Bashir U, Rapolu S, Mamatha N, Sravani S. Effect of Different Dentifrices on the Surface Roughness of Acrylic Resins: An in vitro Study. J Contemp Dent Pract 2017;18(8):679-682.


Author(s):  
Laila Baidas ◽  
Huda Alkawari ◽  
Nada Alshihah ◽  
Ghaida Almashaan ◽  
Haya Alwaalan

Introduction: Acid regurgitation caused by gastro-oesophageal reflux disease can lead to decreases in intraoral pH below the critical pH for orthodontic appliances. Exposure of brackets and archwires to such acidic environments causes changes in the surface properties that affect the frictional forces generated during orthodontic sliding mechanics and reduce the clinical efficacy of the wires. Aim: This in vitro study aimed to determine the effects of simulated gastric acid with pH 1.2 and pH 4 on the surface topography, surface roughness, and frictional resistance properties of different types of orthodontic archwires. Materials and Methods: A comparative in vitro study evaluated a total of 135 samples of three commercially available archwires: Stainless Steel (SS), nickel titanium, and beta-titanium (n=45/group). Each archwire was divided into three subgroups (n=15) according to different pH solutions: distilled water (control; pH 6.7), pH 4, and pH 1.2. The samples in the two acidic pH subgroups were immersed in the respective solution for two minutes, rinsed with distilled water, and stored in distilled water at 37°C. The procedure was repeated 6 times a day for nine days with 24-hours interval in between each cycle. The surface topography of the wires was examined by scanning electron microscopy, while the surface roughness was inspected by noncontact surface profilometry. Finally, the frictional resistance was measured by a universal testing machine. One-way ANOVA and a Tukey’s post-hoc test were used for analysis, with values of p≤0.05 considered significant. Results: The results showed an increase in surface roughness of the SS (p<0.001) and beta-titanium (p=0.003) wires as the acidity of the solution increased. The SS wires showed the lowest frictional resistance in pH 1.2 solution among the wires used (p=0.005). No correlation was found between surface roughness and frictional resistance in this study. Conclusion: Increased acidity condition significantly affects the surface roughness of beta-titanium and SS wires, and has no effect on the frictional behaviour of the orthodontic wires expects in the SS wires. Thus, because the surface properties of the archwires can be affected by acidity in the oral cavity, it is recommended to change the orthodontic wires regularly throughout orthodontic treatment, especially in patients with gastro-oesophageal reflux disease.


2020 ◽  
Vol 33 (2) ◽  
pp. 59-68
Author(s):  
Bruna Tavares ◽  
Fabiana França ◽  
Roberta Basting ◽  
Basting Turssi ◽  
Turssi Amaral

The aim of this in vitro study was to evaluate the effect of bleaching protocols on the surface roughness (Ra), color change and surface micromorphology of a low-viscosity bulk-fill composite (Filtek Bulk Fill Flow, 3M ESPE), a highviscosity bulk-fill composite (Filtek Bulk Fill, 3M ESPE) and a conventional nanoparticulate composite resin (control) (Filtek Z350 XT, 3M ESPE). Forty samples of each composite (disks 5 mm in diameter and 2 mm thick) were randomly divided into four groups (n=10), according to bleaching protocol: a) 10% carbamide peroxide gel (Opalescence, Ultradent Products) (2 h/ day, for 14 days); b) 40% hydrogen peroxide gel (Opalescence Boost, Ultradent Products) (three bleaching sessions, once a week, 45 min/session); c) whitening rinse (Listerine Whitening Extreme, Johnson & Johnson) (2 min/day, for 14 days); and d) distilled water (control). The samples were submitted to triplicate readings (Ra and color [CIELAB parameters]) before and after contact with bleaching protocols. Micromorphology was analyzed in a scanning electron microscope (SEM). Ra and color parameters (ΔL, Δa, Δb and ΔE) were analyzed by generalized linear models (α=0.05). The Ra of the high-viscosity bulk-fill was significantly higher than that of the other composites (p<0.05). Ra increased significantly (p<0.05) and surface became more irregular (SEM analysis) in all the composite resins, regardless of the bleaching protocol (p<0.05). The high-viscosity bulk-fill composite resin group had significantly lower ΔE (p<0.05) than the nanoparticulate composite resin group immersed in distilled water. It was concluded that the characteristics of each resin significantly influenced the Ra more than the bleaching protocol. The high-viscosity bulk-fill resin presented minor color change.


2016 ◽  
Vol 17 (10) ◽  
pp. 801-806 ◽  
Author(s):  
Ra'fat I Farah ◽  
Naji Al-Harethi

ABSTRACT Aim The aim of this study was to compare in vitro the marginal microleakage of glass ionomer-based provisional cement with resin-based provisional cement and zinc oxide non-eugenol (ZONE) provisional cement in computer-aided design and computer-aided manufacturing (CAD/CAM)-fabricated interim restorations. Materials and methods Fifteen intact human premolars were prepared in a standardized manner for complete coverage of crown restorations. Interim crowns for the prepared teeth were then fabricated using CAD/CAM, and the specimens were randomized into three groups of provisional cementing agents (n = 5 each): Glass ionomer-based provisional cement (GC Fuji TEMP LT™), bisphenol-A-glycidyldimethacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) resin-based cement (UltraTemp® REZ), and ZONE cement (TempBond NE). After 24 hours of storage in distilled water at 37°C, the specimens were thermocycled and then stored again for 24 hours in distilled water at room temperature. Next, the specimens were placed in freshly prepared 2% aqueous methylene blue dye for 24 hours and then embedded in autopolymerizing acrylic resin blocks and sectioned in buccolingual and mesiodistal directions to assess dye penetration using a stereomicroscope. The results were statistically analyzed using a nonparametric Kruskal–Wallis test. Dunn's post hoc test with a Bonferroni correction test was used to compute multiple pairwise comparisons that identified differences among groups; the level of significance was set at p < 0.05. Results All groups exhibited marginal microleakage; the Bis-GMA/TEGDMA resin-based provisional cement demonstrated the lowest microleakage scores, which were statistically different from those of the glass ionomer-based provisional cement and the ZONE cement. Conclusion The provisional cementing agents exhibited different sealing abilities. The Bis-GMA/TEGDMA resin-based provisional cement exhibited the most effective favorable sealing properties against dye penetration compared with the glass ionomer-based provisional cement and conventional ZONE cement. Clinical significance Newly introduced glass ionomer-based provisional cement proved to be inferior to resin-based provisional cement as far as marginal microleakage is concerned. How to cite this article Farah RI, Al-Harethi N. Microleakage of Glass Ionomer-based Provisional Cement in CAD/CAM-Fabricated Interim Crowns: An in vitro Study. J Contemp Dent Pract 2016;17(10):801-806.


2018 ◽  
Vol 51 ◽  
pp. 1-12 ◽  
Author(s):  
Dimitrios Dionysopoulos ◽  
Eugenia Koliniotou-Koumpia

The aim of this in vitro study was to investigate the changes in surface roughness of different nanocomposite restoratives and enamel after application of 1.23% acidulated phosphate fluoride (APF) gel. Twelve specimens were prepared for each composite material and human enamel. The APF gel was applied to the surface of the six specimens of each experimental group for 60 sec every 24 h for 4 days. The other six specimens did not receive APF treatment (control). The surface roughness was measured using a VSI microscope. One-way ANOVA and Tukey’s test were used to compare surface roughness between materials for each experimental group at a level of significance of a=0.05. There were no statistically significant differences in Ra values among the composites which did not receive APF treatment (p>0.05). After APF treatment the lowest surface roughness exhibited enamel (0.18±0.04 Ra) and the highest Dyract Extra (0.62±0.07 Ra) followed by Tetric EvoCeram (0.59±0.06 Ra) and Beautifil II (0.51±0.06 Ra). Filtek Z350 XT presented the lowest Ra values (0.23±0.03). All the experimental groups exhibited higher Ra values after APF treatment (p<0.05), except for Filtek Z350 XT (p>0.05). Application of APF gel on the specimen surfaces influenced the surface roughness of enamel and the tested dental composite restoratives depending on their composition.


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4103
Author(s):  
Maite Aretxabaleta ◽  
Alexey Unkovskiy ◽  
Bernd Koos ◽  
Sebastian Spintzyk ◽  
Alexander B. Xepapadeas

Different approaches for digital workflows have already been presented for their use in palatal plates for newborns and infants. However, there is no evidence on the accuracy of CAD/CAM manufactured orthodontic appliances for this kind of application. This study evaluates trueness and precision provided by different CAM technologies and materials for these appliances. Samples of a standard palatal stimulation plate were manufactured using stereolithography (SLA), direct light processing (DLP) and subtractive manufacturing (SM). The effect of material (for SM) and layer thickness (for DLP) were also investigated. Specimens were digitized with a laboratory scanner (D2000, 3Shape) and analyzed with a 3D inspection software (Geomagic Control X, 3D systems). For quantitative analysis, differences between 3D datasets were measured using root mean square (RMS) error values for trueness and precision. For qualitative analysis, color maps were generated to detect locations of deviations within each sample. SM showed higher trueness and precision than AM technologies. Reducing layer thickness in DLP did not significantly increase accuracy, but prolonged manufacturing time. All materials and technologies met the clinically acceptable range and are appropriate for their use. DLP with 100 µm layer thickness showed the highest efficiency, obtaining high trueness and precision within the lowest manufacturing time.


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