Browsing by Subject "Abrasion"
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Item Fluoride Release from Two High-Viscosity Glass Ionomers after Exposure to Fluoride Slurry and Varnish(MDPI, 2019-11-15) Nassar, Hani M.; Platt, Jeffrey A.; Biomedical Sciences and Comprehensive Care, School of DentistryThe effect of brushing with different fluoride slurries on the fluoride release (FR) of different high-viscosity glass ionomer cements (GICs) was investigated. Fifty-eight discs were fabricated from two high-viscosity GICs (GC Fuji IX (F9) and 3M ESPE Ketac-fil (KF)). Five specimens from each brand were used to measure Vickers microhardness and the remaining were randomly assigned to one of four groups (n = 6) based on two-factor combinations: (1) fluoride concentration in the abrasive slurry (275 or 1250 ppm fluoride as NaF) and (2) immersion in a 22,500 ppm fluoride-containing solution. Specimens were brushed for a total of 20,000 strokes over 4 days with daily FR measurement. Data were analyzed using analysis of variance and Bonferroni tests (α = 0.05). Baseline FR and microhardness values were different between the two tested material brands. Exposure to a 22,500 ppm solution was associated with higher FR but not the exposure to 1250 ppm slurries. Brushing and immersion of glass ionomer cements in a 22,500 ppm F solution led to higher FR that was more sustained for KF. Type of the glass ionomer, progressive brushing, and fluoride varnish affected FR but not the fluoride content in the abrasive slurry.Item The Impact of Mouthrinses on the Efficacy of Fluoride Dentifrices in Preventing Enamel and Dentin Erosion/ Abrasion(2018) Albeshir, Ebtehal; Lippert, Frank; Cook, Norman B.; Hara, AndersonObjective: Toothbrushing with fluoride toothpaste followed by rinsing with mouthwash is a routine procedure to maintain good oral hygiene. It is unknown to what extent these rinses can modulate the effect of fluoride in its ability to prevent erosion/abrasion.The aim of this in-vitro study was to investigate and compare the impact of chlorhexidine (CHX), essential oils (EO) and cetylpyridinium chloride (CPC) mouthrinses on erosive tooth wear protection afforded by conventional fluoride toothpastes. Materials and Methods: The following experimental factors were considered: five rinses: CHX, EO, CPC, a fluoride rinse, and deionized water, two fluoride toothpastes: stannous fluoride (SnF2) or sodium fluoride (NaF) and two models: (erosion/ erosion+abrasion). Slabs of bovine enamel and dentin were prepared and embedded in resin blocks and generated 10 enamel and dentin testing groups (n = 8). UPVC tapes were placed on the sides of each slab leaving 1mm area exposed in the center. The blocks were subjected to a five-day cycling model. Then, the blocks were placed in a brushing machine and exposed to fluoride toothpaste slurry (one side was brushed and the other wasn’t). The blocks were then exposed to rinse treatments. Artificial saliva was used to remineralize the specimens after erosions and treatment challenges, and as storage media. After the fifth day of cycling, surface loss (in micrometers) was determined by profilometer. Data were analyzed using ANOVA (α = 0.05). Results: There was no interaction among the three factors (type of toothpaste, mouthrinse and abrasion or not (dentin p = 0.0520, enamel p = 0.4720). There were no significant two-way interactions as SL was only affected by toothpaste and mouthrinse. NaF caused less SL than SnF2 (4.60 vs. 5.83 μm; p < 0.0001) in dentin, whereas the opposite was found in enamel (5.20 vs. 3.56 μm; p < 0.0001). Toothbrushing abrasion caused comparatively more SL in enamel (6.53 vs. 2.23 μm; p < 0.0001) than in dentin (6.06 vs. 4.38 μm; p < 0.0001). None of the tested mouthrinses affected SL. Conclusion: Commonly used mouthrinses containing antimicrobial agents or additional fluoride, do not impair the erosion/abrasion protection afforded by fluoride toothpastes. Tested SnF2 dentifrice offered greater protection against enamel surface loss and NaF dentifrices showed more protection for the dentin surface. Clinical relevance: The understanding of the interaction between commonly used rinses and fluoride dentifrices will help dentists provide better recommendations to patients with erosive lesions.Item Impact of Toothbrush Head Configuration and Dentifrice Abrasivity on Non-Carious Cervical Lesions Development In-Vitro(2022) Alzahrani, Lina; Hara, Anderson T.; Lippert, Frank; Al Dehailan, LailaBackground: Non-carious cervical lesions (NCCLs) result from the loss of tooth structure at the cemento-enamel junction for reasons unrelated to dental caries.1 NCCLs have been attributed to processes of dental abrasion, erosion and/or abfraction.7 In this study, we focused on the effects of excessive toothbrushing abrasion, resulting from the mechanical interaction between the tooth, toothbrush, and toothpaste. Purpose: The aim of this in vitro study was to investigate the effect of toothbrush head configuration and toothpaste abrasivity combinations on the development and progression of simulated NCCLs, evaluated by 3D optical profilometry. Hypotheses: The study hypotheses were: a) the abrasive level of the dentifrice and toothbrush bristle configuration have a significant influence on the initiation and progression of NCCLs independently; and b) the association between the abrasive level and toothbrush head configuration does affect the initiation and the progression of NCCLs. Materials and Methods: A total of 240 extracted human upper first premolars, free of any dental caries, restorations, stains, or enamel and root defects were selected. The teeth were cleaned with a hand periodontal scaler and randomly allocated into 15 groups (n = 16), generated by the association between toothbrushes of different head configurations (ordinary/flat-trimmed, rippled, cross-angled/multileveled/rubber, cross-angled/multileveled/flex head and feathered) and toothpaste abrasivity (low, medium, and high, simulated using different silica abrasives) in a factorial design. The dental specimens were mounted on custom-made acrylic blocks, and their root surfaces were partially covered with acrylic resin to simulate the gingiva, leaving a 2-mm area in length apical to the cemento-enamel junction exposed to toothbrushing. The specimens were brushed with the tested toothbrushes and abrasive slurries for a total of 35,000 and 65,000 double strokes. Specimens were analyzed by optical profilometry at baseline and after each brushing cycle. The outcome variable was dentin volume loss (mm3), calculated by image subtraction. Data were analyzed using mixed-model analysis of variance (ANOVA). Significance of the Results: Oral health maintenance and effective plaque control depend on the combined usage of a toothbrush and a toothpaste. Specific combinations of toothbrush and toothpaste associated with excessive toothbrushing may lead to tooth wear. Results obtained from this study will showed how different combinations of toothbrush head configuration and toothpaste abrasivity affect NCCL development and progression. Results: A significant interaction among the experimental factors (toothbrush type abrasive level brushing cycles) was observed (p = 0.05). All toothbrushes caused significantly more tooth wear when associated with the high-abrasivity slurry, as compared to medium- and low-abrasivity slurries. The medium-abrasivity slurry caused significantly more tooth wear than the low-abrasivity slurry. At both testing points and when associated with the low abrasivity slurry, the Feathered toothbrush was the least abrasive. At 35,000 brushing cycles, the flat-trimmed toothbrush was the most abrasive. At 65,000 brushing cycles, the flat-trimmed toothbrush was the most abrasive only when associated with the high-abrasivity slurry, and the multileveled/rubber bristles was the most abrasive when associated with the medium- and high-abrasivity slurries. Overall, 35,000 brushing cycles resulted in significantly less tooth wear than 65,000 brushing cycles. Conclusion: Considering the limitations of this study, it can be suggested that for patients at higher risk of developing NCCLs, ordinary/flat-trimmed toothbrushes are not favorable options. According to the abrasive level of the toothpaste, either feathered or multileveled/flex head may be more suitable to prevent the development of NCCLs.Item Influence of ceramic (feldspathic) surface treatments on the micro-shear bond strength of composite resin(E.H Angle Education and Research Foundation, 2010-07-01) Yadav, Sumit; Upadhyay, Madhur; Borges, Gilberto Antonio; Roberts, W. Eugene; Orthodontics and Oral Facial Genetics, School of DentistryObjective: To test the null hypothesis that surface treatment has no influence on the micro-shear bond strength between orthodontic composite resin cement and ceramics (feldspathic porcelain). Materials and Methods: Circular specimens of feldspathic porcelain were fabricated and randomly divided into six groups: (1) no treatment; (2) treatment with a mixture of acidic primer and silane agent for 20 seconds; (3) etching with 9.5% hydrofluoric acid; (4) etching with 9.5% hydrofluoric acid and coating with a mixture of acidic primer and silane agent for 20 seconds; (5) airborne-particle abrasion with 50-μm aluminum oxide; and (6) airborne-particle abrasion and coating with a mixture of acidic primer and silane agent for 20 seconds. The porcelain disks were then bonded to resin cylinders with composite resin cement. A micro-shear bond test was carried out to measure the bond strength. Moreover, each ceramic surface was observed morphologically by scanning electron microscopy. One-way analysis of covariance was used to compare the groups for differences in micro-shear bond strength. Results: The mean micro-shear bond strength varied as a function of surface treatment. It ranged from 3.7 to 20.8 MPa. The highest values for micro-shear bond strength were found when the surface was acid-etched with hydrofluoric acid and coated with silane. On the other hand, the control group (no treatment) had significantly lower micro-shear bond strength than all the other groups. Conclusion: The null hypothesis that the surface treatment has no influence on the micro-shear bond strength of orthodontic composite resin was rejected. The bond strength between ceramics and orthodontic resin cement is affected by the ceramic surface treatment. The bond failure was of the adhesive type, except with the hydrofluoric acid + silane group, where it was a cohesive bond failure.Item Influence of Toothbrush Abrasion and Surface Treatments on Roughness and Gloss of Polymer-Infiltrated Ceramics(MDPI, 2021-10-27) Labban, Nawaf; Al Amri, Mohammad D.; Alnafaiy, Sarah M.; Alhijji, Saleh M.; Alenizy, Mohammad A.; Iskandar, Mounir; Feitosa, Sabrina; Biomedical Sciences and Comprehensive Care, School of DentistryThe aim of this study was to compare the surface roughness and gloss of polymer-infiltrated ceramics after simulated in vitro toothbrushing in different storage mediums. Four polymer- infiltrated ceramics were evaluated, Lava ultimate (LU), Vita enamic (EN), Shofu (SH), and Crystal ultra (CU). The control group was a feldspathic ceramic, Vita Mark II (VM). One hundred and twenty specimens (12 × 14 × 2.5 mm) were prepared using a precision saw. For each material (n = 24), the specimens were allocated into two groups, polished and stained. The specimens of each group were stored (for 7 days) in either citric acid (0.2N) or distilled water. Data for surface gloss (ΔE*SCE-SCI) and roughness (Ra) were evaluated before (baseline) and after simulated toothbrushing. For toothbrushing simulation, a toothpaste slurry containing a toothpaste of 100 relative dentin abrasion (RDA) and 0.3 ml distilled water was used for 3650 cycles (7300 strokes) for each specimen. Data were analyzed using t-test and ANOVA. A p-value of ≤ to 0.05 was considered significant. The highest mean value of surface gloss was identified in CU (stained-water) (4.3 (0.47)) (ΔE*) and EN (stained-acid) (4.3 (1.00)) (ΔE*) specimens, whereas the lowest mean value was shown by SH (stained-acid) (2.04 (0.42)) (ΔE*) samples. The highest mean value of surface roughness was observed in SH (0.40 (0.99)) Ra (stained-acid) whereas the lowest in VM (0.13 (0.039)) Ra (polished- water). A significant difference (p < 0.05) was observed in surface roughness and gloss between the materials with simulated toothbrushing, except in VM and LU, respectively. Therefore, it can be concluded that simulated toothbrushing impacts on surface roughness and gloss, irrespective of the storage medium.