Toothbrush Abrasion Research Articles

Acidic/abrasive challenges on simulated non-carious cervical lesions development and morphology

This in vitro investigation assessed how frequency of erosive challenges and duration of toothbrushing abrasion influenced non-carious cervical lesions (NCCLs) development and morphology. Experimental units were prepared using extracted human premolars assigned to four erosive-abrasive frequency protocols (n=16): F0. No acid exposure (negative control), F2.5 K. Acid exposure (1 % citric acid at natural pH) every 2500, F5K. 5000 and F15K. 15000 brushing-strokes. All groups were brushed for 55000 total brushing-strokes. Three-dimension images of the teeth were captured at baseline, after 15000, 35000 and 55000 brushing-strokes, using an intraoral scanner (TRIOS4, 3Shape). WearCompare software (Leeds Digital Dentistry) was used to analyze volumetric tooth loss (mm3) by superimposition followed by subtraction analysis. Lesion angle was measured (ImageJ, NIH) and morphology visually classified. Data were analyzed using ANOVA and Fisher's Exact tests adopting two-sided 5 % significance level. Tooth loss increased with brushing-strokes overall (p<0.001) and for each erosive-abrasive protocol (p<0.001). Acid exposure significantly increased tooth loss (p<0.001), regardless of brushing interval (p<0.001), however by 35000 strokes no tooth loss difference was observed among acid-exposed groups (p>0.05). Control had significantly sharper mean lesion angle (59°) than all acid-exposed groups (∼145°) (p<0.001), and significantly different lesion shape with 94 % wedge-shaped lesions versus 0 %, respectively (p<0.001). In contrast to the control, acid exposure was associated to more striated lesions. Simulated NCCLs developed and progressed differently and more rapidly in the presence of acidic challenges, regardless of their frequency. Exposure to acid impacted the morphology of lesions.

Effects of two dentifrices on the surface properties and staining susceptibility of polymer-based materials.

This study examined the effect of whitening and abrasive regular dentifrices on the surface characteristics and stain susceptibility of polymer-based CAD-CAM blocks subjected to artificial toothbrushing abrasion (TB). Two resin composite blocks [CeraSmart (CS) and Grandio Blocs (GB)], one polymer-infiltrated ceramic [Vita Enamic (VE)], and one direct resin composite [GrandioSO (RC)] were used to produce 60 specimens. The baseline mass, gloss, roughness, Vickers hardness (Hv), and color were measured after 7 days of water storage. The specimens were then separated into three TB treatment groups (n = 5): water control (C), regular daily dentifrice (R), and whitening dentifrice (W). Measurements were repeated post-TB (20,000 cycles). All specimens were immersed in coffee, and the CIE ΔE00 was measured after 1, 7, and 14 days. Two-way, one-way ANOVA, and Tukey's post hoc tests were performed to determine any significant differences between the materials and TB groups. To determine the stain resistance, repeated measures of ANOVA, one-way ANOVA, and Tukey's post hoc tests were used (α = 0.05). The R and W mass changes were minimal (-3.77 to 3.16g%). W reduced the gloss of all the materials by 12.6%-65%. All materials in W were slightly rougher (Ra, 0.107-0.144 μm) than those in R (Ra, 0.049-0.072 μm). The ΔE00 ranged from 0.6 to 1.6 in W and 0.4 to 1.4 in R. VE was the hardest material at baseline (Hv = 362), whereas brushing and staining lowered Hv in all TB groups (282.8-300.6). After brushing in W, VE, and RC were more susceptible to coffee stains than were CS and GB. The whitening dentifrice roughened CAD-CAM specimens, reducing gloss, yet lightened some materials. Polymer-infiltrated ceramic and direct resin composite specimens brushed with abrasive regular or whitening dentifrice resulted in more intense staining than the CAD-CAM resin composites.

Comparative Evaluation of Surface Roughness and Color Stability Between Single-Shade Composite and Multi-Shade Composite: An In Vitro Study.

Introduction Composite resin materials are a popular choice for direct tooth-colored restorative purposes due to their excellent aesthetic qualities and versatility. The key determinants that impact the visual aspect of the restoration are gloss, surface roughness, and color stability. Research indicates that there is a direct correlation between the level of roughness on a composite resin surface and the likelihood of discoloration. The aim of this study was to compare and evaluate the surface roughness and color stability of a single-shade and multi-shade composite resin after subjecting it to toothbrush simulation and immersion in coffee and an aerated drink. Materials and methods Ten single-shade composite resinsand 10 multi-shade composite resins were packed into a Teflon mold and light cured. Pre-operative surface roughness values were evaluated using a surface profilometer. Toothbrush abrasion was simulated using a toothbrushing simulator. All these resin molds were then evaluated for initial color using a spectrophotometer machine (Konica Minolta, Japan). Five resin molds were then immersed in a beaker containing coffee for seven days and five resin molds were immersed into a beaker containing an aerated drink for seven days. Following this, the resin molds were re-evaluated for color stability using a spectrophotometer machine. Results The results of this study show that single-shade composite showed increased discoloration when compared with multi-shade composite resin. Also, there is a statistical difference between the single-shade composite and multi-shade composite when it comes to surface roughness and discoloration. Conclusion With the limitations of the present study, it can be concluded that single-shade composite resins have more discoloration potential in beverages than multi-shade composite resins.

Surface roughness and gloss retention of bioactive resin composite after simulated toothbrush abrasion

Background. Newly introduced bioactive resin composites are being used more often. Few studies have evaluated the influence of toothbrush abrasion on their surface characteristics. Methods. This study aims to assess the surface roughness (Ra) and gloss values (GU) of 3 bioactive composites and a conventional nanohybrid composite before and after simulated toothbrush abrasion. Five samples each of Filtek Z250 XT, Beautifil Flow Plus, Activa Presto and Predicta Bioactive Bulk were subjected to 10,000 cycles of simulated toothbrush abrasion. Ra and GU values were evaluated at baseline and after each 2,500 cycles. Results. Significant difference was found in both Ra and GU (P < 0.001). For each material, GU gradually decreased as the brushing cycles increased. GU values of Beautifil Flow Plus were significantly higher at the baseline, 2,500- and 5,000-cycles stages (P < 0.05). The GU values were 78.20 (7.20), 69.67 (6.17) and 63.30 (5.52) respectively. Activa Presto showed the lowest mean GU after 10,000 cycles. A significant increase in Ra at each of the measuring stages was observed in all materials compared to the baseline measurement (P < 0.001). No significant difference in Ra values of all four materials at the baseline and up to 5,000-cycles (P > 0.05). After 7,500 cycles, the mean Ra value of Activa Presto at 0.64 (0.14) was significantly higher than that of Z250 XT at 0.49 (0.03) (P < 0.001). At 10,000 cycles, Activa Presto had significantly higher Ra at 0.70 (0.10) when compared to Z250 XT at 0.52 (0.08), Beautifil Flow Plus at 0.56 (0.07) and Predicta Bioactive Bulk at 0.59 (0.10) (P < 0.001). Conclusion. All materials showed an increase in Ra and decrease in GU after simulated toothbrushing.

Antifungal Effect and Durability of Chitosan Oligosaccharide Coating on Heat-cured Polymethylmethacrylate Surface

This study aimed to investigate the antifungal effect against Candida albicans (ATCC® 10231) and the durability of chitosan oligosaccharide (COS) coated on heat-polymerized polymethylmethacrylate (PMMA). The various concentrations of COS solution, 0.5, 1 and 2-fold of minimum fungicidal concentration (0.5, 1 and 2 MFC) were prepared and applied to PMMA specimens treated with sandblasting (SB), application of 3-aminopropyltriethoxysilane (APS), and a combination of both procedures (SB&amp;APS). The toothbrush abrasion test was done to evaluate the remaining COS (n=10). The antifungal effect was determined through the colony count method (n=3). The number of fungal colonies was recorded at 16 and 48 hours. Data were analyzed using two-way and one-way ANOVA at the 95% confidence level. The result of the toothbrush abrasion test revealed that COS concentration and surface treatment affected coating durability. APS and SB&amp;APS groups showed a high percentage of COS and significantly differed from SB groups (P = 0.00). For the antifungal effect, coatings with 1 MFC and 2 MFC demonstrated no difference, but coating with 0.5 MFC differed from others (P = 0.00). At 16 and 48 hours, PMMA coated with 1 MFC and 2 MFC by APS and SB&amp;APS methods inhibited C.albicans. COS can be coated onto PMMA using APS and can inhibit C.albicans. With further development, this method could be applied to treat denture stomatitis alternatively to conventional antifungal drugs. Keywords: Candida albicans, Chitosan, Oligochitosan, Polymethylmethacrylate, Silanes

Konvansiyonel, Eksiltmeli ve Eklemeli İmalat Tekniklerinde Kullanılan Geçici Kron Materyallerinin Yüzey Pürüzlülüğüne Diş Fırçalama ve Yüzey İşlemlerinin Etkisi: İn Vitro Çalışma

Background: This study aimed to compare the effect of the surface treatment and toothbrushing abrasion on the surface roughness of interim crown material specimens manufactured using conventional, subtractive, and additive processing techniques.&#x0D; Material and methods: 80 disk-shaped specimens were prepared from 4 different interim crown materials; one auto-polymerized polymethyl methacrylate resin (PMMA);(IM) and one bis-acryl composite resin;(AC) for conventional technique, one computer-aided design/computer-aided manufacturing (CAD-CAM) PMMA block;(TC) for subtractive process, one 3-dimensionally (3D) printed resin;(CB) for additive process. Specimens of each interim crown material were divided into two subgroups according to applied surface treatments; conventional polishing or surface sealant agent coupling (n=10). The surface roughness values of specimens before (Ra0) and after 10,000 cycles of toothbrushing (Ra1) were measured with a profilometer. Data were statistically analyzed.&#x0D; Results: The polished groups of all interim crown materials showed significantly higher Ra0 values compared to the sealant groups before toothbrushing (p˂0.05). While the polished IM groups exhibited the highest Ra0 value (0.44±0.08), the sealed TC groups exhibited the lowest Ra0 value (0.23±0.06). The Ra values of all material groups increased after simulated 1-year toothbrushing. While the polished IM group exhibited the highest Ra1 value (0.45±0.14), the sealed CB group had the lowest Ra1 value (0.31±0.09).&#x0D; Conclusion: It was observed that toothbrushing caused an increase in the surface roughness of all interim materials. The application of a surface sealant agent to these materials is more effective than polishing to reduce surface roughness. Sealed 3D printed resin for additive process exhibited the lowest mean roughness value after toothbrushing.&#x0D; Keywords: Additive Manufactured, Interim Crown Material, Roughness, Subtractive Manufactured, Toothbrushing Abrasion

Supplementation of Energy Drinks with Green Tea Extract: Effect on In Vitro Abrasive/Erosive Dentin Wear.

To investigate the effect of the supplementation of energy drinks with green tea extract on abrasive and erosive dentin wear. Six groups, each comprising 15 bovine dentin samples, were prepared, yielding a total of 90 samples. Erosion was performed by immersing the samples in Red Bull and Red Bull light with and without green tea extract. Tap water with and without green tea extract was used as the control groups. The samples were subjected to abrasive/erosive cycling for five days. The following cycling was performed daily: toothbrush abrasion (20 brushstrokes; 2.5 N); eight erosive cycles (2 min storage in the respective solutions); in between the erosive cycles, storage in artificial saliva (60 min) and again toothbrush abrasion (20 brushstrokes; 2.5 N). During the night, samples were again stored in artificial saliva. Abrasive/erosive dentin wear was measured using a stylus profilometer (µm, accuracy = 40 nm). The measured dentin loss results from the vertical position shift on the y-axis from base to final profile after the wear process in 2D. Pairwise comparisons between the groups were carried out using Wilcoxon signed-rank test. The following dentin wear (median [IQR]) was measured: Red Bull: 1.9 µm (0.5); Red Bull Light: 1.3 µm (0.3); Red Bull with green tea extract: 0.8 µm (0.3); Red Bull Light with green tea extract: 0.3 µm (0.5); Tap water with green tea extract: -0.2 µm (0.7); Tap water: -1.0 µm (1.2). The comparison of all tested groups to each other proved to be statistically significant (p < 0.05). The supplementation of energy drinks with green tea extract provide a protective effect against erosive/abrasive wear in vitro.

Surface Properties of Resin Composites and CAD/CAM Blocks After Simulated Toothbrushing.

This study aimed to evaluate the surface gloss, surface roughness, and color change of restorative materials after a three-body wear abrasion. Four resin composites with different filler particle size (Gracefil Flo [GFF, 0.7 μm], Gracefil LoFlo [GFL, 0.25 μm], Gracefil ZeroFlo [GFZ, 0.15 μm], and Gracefil Putty [GFP, 0.3 μm]), two CAD/CAM resin composite blocks with different filler particle size (Cerasmart 300 [CS3, 0.7 μm] and Cerasmart Prime [CSP, 0.3 μm], GC), and one CAD/CAM lithium disilicate glass-ceramic block (Initial LiSi Block [ILS], GC) as a control were evaluated. Twenty slab-shaped specimens were obtained from each material. Ten specimens were subjected to 80,000 toothbrushing strokes and measured for surface gloss (Gloss Unit, GU), surface roughness (Ra, μm), and color (L*, a*, and b* values) before toothbrushing and at every 20,000 strokes. Color differences (ΔL*, Δa*, Δb*, and ΔE00) before and after toothbrushing were calculated. After 80,000 strokes, abraded surfaces were observed using scanning electron microscopy. The other 10 specimens were measured for Vickers microhardness (VHN). After 80,000 toothbrushing strokes, the mean GU ranged from 60.43 to 16.12 (the highest for ILS and lowest for GFL), and the mean Ra ranged from 0.079 to 4.085 (the lowest for ILS and highest for GFL). At all measuring stages, the calculated ΔE00 values ranged from 0.31 to 0.92 for all materials. The mean VHN ranged from 632.34 to 39.08 (the highest for ILS and lowest for GFZ). The resin composite containing the largest filler particle (GFF) showed significantly lower Ra and higher VHN than other resin composites (GFL, GFZ, and GFP). The CAD/CAM resin composite block containing a smaller filler particle (CSP) retained significantly higher GU than that containing a larger filler particle (CS3). A negative correlation between GU and Ra was detected. Based on the findings, toothbrush abrasion induced a decrease in GU and an increase in Ra for all resin-based materials tested. Resin-based materials with larger filler size tended to show lower Ra, while resin-based materials with smaller filler size tended to show a smaller reduction in GU. These were more pronounced for light-cure resin composites than for resin composite blocks for CAD/CAM.

Isolated effect of filler particle size on surface properties of experimental resin composites before and after toothbrush abrasion.

This study aimed to isolate the relationship between filler size and the surface properties of roughness and gloss before and after toothbrush abrasion for experimental resin-based composites (RBCs) containing uniform spherical fillers. Five experimental light-cured RBCs with different spherical filler sizes and three commercial RBCs were studied. Forty specimens were polished using silicon carbide papers. Gloss was measured after 0, 90, 180, and 360 min of simulated toothbrushing, and surface roughness was measured before and after 360 min of toothbrushing. Two-way ANOVA/Tukey's multiple comparison tests were used to compare the RBCs, and the correlation between particle size and surface roughness or gloss was also determined. After polishing and toothbrushing, RBCs with smaller fillers exhibited significantly higher gloss and lower surface roughness, and RBCs with larger fillers exhibited lower gloss and higher surface roughness. A significant correlation was found between filler particle size and gloss and surface roughness both before and after toothbrush abrasion. Gloss of RBCs containing fillers with larger particle sizes was significantly reduced. After toothbrushing abrasion, the surface roughness increased for all RBCs, except those containing the finest-sized fillers. The particle size of the filler is a critical determinant of the surface roughness and gloss of RBCs, after polishing and after toothbrushing. Increased surface roughness caused by toothbrush abrasion reduces the gloss of resin-based composites. Resin-based composites containing finer fillers best maintain glossiness after routine tooth brushing.

Wear behavior of ceramic, composite, and ceramic/composite interfaces

Objective. This study has aimed to evaluate the effects of toothbrushing on the wear behavior of two composites, three ceramic materials, and ceramic/composite interfaces. Material and Methods. Nanofilled (Filtek Ultimate), and nanohybrid composites (Spectra ST HV) were used for the repair of a hybrid ceramic (Vita Enamic), resin nanoceramic (Katana Avencia), and zirconia block (Katana Zirconia). Composites, ceramics, and ceramic/composite interfaces were examined before and after a period of one-month and one-year of toothbrush abrasion testing using non-contact optical profilometry and scanning electron microscopy (SEM). Data were analyzed by two-way ANOVA and Bonferroni correction. The statistical significance level was set at p < 0.05. Results. No difference was found between the surface roughness of the Vita Enamic, Katana Avencia, Filtek Ultimate, and Spectra surfaces after one month and one year of toothbrushing. Sa values in Katana Zirconia material were found to be significantly lower than those in the control group after one year of brushing. The surface roughness of the repair interfaces formed by repairing hybrid ceramic and resin nanoceramic CAD/CAM materials with nanofilled and nanohybrid composite materials was found to be similar after different brushing times. Conclusion. Vita Enamic, Katana Avencia, Filtek Ultimate, and Spectra materials can be preferred in clinical repair applications, since they exhibit similar wear behavior after brushing at different times. For the zirconia material, the repair interface had similar surface roughness as the ceramic and composite surfaces after one year of brushing. Periodic recalls and re-polishing may thus be necessary when these products are used clinically.

Influence of toothbrush abrasion on the surface characteristics of CAD/CAM composite resin blocks with shade gradations.

Crown restorations in anterior region are recommended highly color-reproductivity because of aesthetic reason. Composite resin block with several shade gradations is especially produced for anterior restorations. To clarify the durability of an aesthetic, the effect of toothbrush abrasion on surface properties was performed. Composite-resin blocks without shade gradation and a ceramic block were used as controls. All specimens were prepared using #2000 SiC paper and polished using an aluminum oxide polishing paste. Toothbrush abrasion tests were carried out for 20,000 cycles at a frequency of 2 Hz with 2.0 N load. Gloss and surface roughness were measured before and after toothbrush abrasion. The number of repetitions was set to five. It was clarified that tooth brushing caused to decrease in the gloss and to increase in the surface roughness with significant negative correlations between these results not only in composite-resin blocks without shade gradation but also in those with gradation.

Surface roughness and gloss alteration of polished resin composites with various filler types after simulated toothbrush abrasion

Background/purposeFew studies have focused on the influence of simulated toothbrush abrasion on the surface qualities of novel nanofilled and nanohybrid composites. The aim of the study was to evaluate the surface roughness and gloss values of resin-based composite (RBC) materials with various filler types before and after simulated toothbrush abrasion. Materials and methodsOne nanofilled (Filtek Z350 XT [FT3]), two nanohybrids (Harmonize [HM] and Clearfil Majesty [CM]) and one microhybrid (Filtek Z250 [FT2]) were evaluated. Twelve specimens of each material were made and polished with silicon carbide sandpapers. Initial surface roughness and gloss values were measured as negative controls. Then, all specimens were subjected to simulated toothbrush abrasion on a custom-made apparatus. After 2000, 4000 and 8000 cycles, the surface roughness and gloss values of all specimens were tested. One additional specimen from each group was selected for scanning electron microscope (SEM) analysis. ResultsFor FT3, Ra and GU values did not significantly change until after 8000 cycles during the process of toothbrushing (P > 0.05). For HM, CM and FT2, the Ra and GU values significantly decreased after 4000 and 8000 cycles of toothbrush abrasion (P < 0.05). After 8000 cycles of toothbrush abrasion, FT3 presented the lowest surface roughness and highest gloss values of all materials (P < 0.05). SEM images showed that surface textures and irregularities corresponded to the results of surface roughness and gloss. ConclusionSurface roughness and gloss after simulated toothbrush abrasion were material dependent. Nanofilled resin composite presented the lowest Ra values and highest GU values.

Effects of gastric acid and mechanical toothbrushing in CAD-CAM restorative materials: Mechanical properties, surface topography, and biofilm adhesion

ObjectiveTo evaluate the effects of simulated gastric acid erosion combined with mechanical toothbrushing abrasion on the mechanical properties, surface topography, and biofilm adhesion of different CAD/CAM materials. Material and methodsSpecimens of zirconia-reinforced lithium silicate glass-ceramic (ZLS), polymer-infiltrated ceramic network (PICN), feldspathic glass-ceramic (FE), and two nanoceramic resins (RK, RG), were submitted to the following challenges: erosion (E), abrasion (A), erosion combined with abrasion (E + A), or remained untreated (control - C). After challenges, flexural strength was evaluated, while microhardness (KHN) and surface roughness (Ra) were tested before and after treatments. The biofilm adhesion (Streptococcus mutans ATCC 700610, Streptococcus sanguinis ATCC 10556 e Candida albicans MYA 2876) was determined by the counting of colonies forming units per milliliters (UFC/mL) after erosive and abrasive challenges. ResultsFE showed the lowest flexural strengths, while ZLS and RG exhibited the highest, while PICN and RK, had intermediate values. PICN, ZLS, and FE showed lower microhardness after E and E + A challenges than polymer-based materials (RG and RK). FE surface roughness increased after E and E + A challenges and after A and E + A challenges for RK. Biofilm formation after erosive/abrasive challenges was higher on ZLS than FE, RK, and RG, but no different than PICN. RK and RG exhibited the lowest biofilm formation among the groups. Furthermore, E + A challenges held significant changes in the surface of the materials, which were more severe on the surface of glass ceramics and hybrid materials. ConclusionErosive challenges combined with abrasion negatively influenced the mechanical properties and surface topography of most CAD/CAM materials and increased the biofilm adhesion on ZLS. Besides, the severity of the damage is related to the type and composition of each material.

Dual function of quercetin as an MMP inhibitor and crosslinker in preventing dentin erosion and abrasion: An in situ/in vivo study.

The aim of the present study was to evaluate the in situ/in vivo effect of quercetin on dentin erosion and abrasion. Human dentin blocks (2× 2× 2mm) were embedded and assigned to 6 groups: 75μg/mL, 150μg/mL and 300μg/mL quercetin (Q75, Q150, Q300); 120μg/mL chlorhexidine (CHX, positive control); and deionized water and ethanol (the negative controls). The specimens were treated with the respective solutions for 2min and then subjected to in situ/in vivo erosive/abrasive challenge for 7 d as follows: in vivo erosion 4 times a day and then in vivo toothbrush abrasion after the first and last erosive challenges of each day. Dentin loss was assessed by profilometry. An additional dentin specimen was used to evaluate the penetration depth of quercetin into dentin by tracking the spatial distribution of its characteristic Raman peak. Moreover, dentin blocks (7× 1.7× 0.7mm) were used to detect the impact of quercetin on dentin-derived matrix metalloproteinase (MMP) inhibition by in situ zymography, and the inhibition percentage (%) was calculated. Additionally, the potential collagen crosslinking interactions with quercetin were detected by Raman spectroscopy, and the crosslinking degree was determined with a ninhydrin assay. Fully demineralized dentin beams (0.5× 0.5× 10mm) were used to evaluate the impact of quercetin on the mechanical properties of dentin collagen fibre by the ultimate micro-tensile strength test (μUTS). The data were analysed by one-way analysis of variance and Tukey's test (α=0.05). Compared to the negative controls, all treatment solutions significantly reduced dentin loss. The dentin loss of Q150 and Q300 was significantly less than that of CHX (all P<0.05). The amount of quercetin decreased with increasing dentin depth, and the maximum penetration depth was approximately 25-30µm. In situ zymography showed that quercetin significantly inhibited the activities of dentin-derived MMPs. The inhibitory percentages of Q75 and Q150 were significantly lower than that of CHX (all P<0.05), but no significant difference was found between Q300 and CHX (P=0.58). The collagen crosslinking interactions with quercetin primarily involved hydrogen bonding and the degree of crosslinking increased in a concentration-dependent manner. Statistically significant increases in μUTS values were observed for demineralized dentin beams after quercetin treatment compared with those of the control treatments (all P<0.05). This study provides the first direct evidence that quercetin could penetrate approximately 25-30µm into dentin and further prevent dentin erosion and abrasion by inhibiting dentin-derived MMP activity as well as crosslinking collagen of the demineralized organic matrix.

Comparative toothbrush abrasion resistance and surface analysis of different dental restorative materials

Different materials have been used for dental restorations, and, like a natural tooth, they are subject to wear due to abrasion produced by toothbrushing during oral hygiene routine. The purpose of the present study was to evaluate the toothbrush abrasion resistance of four restorative dental CAD/CAM materials available on the market: an acrylic polymer - PMMA (DD TempMED HI, Dental Direkt), a composite resin (BRILLIANT CRIOS cerec HT A1 14, Coltene, CH) and two ceramics (polychromatic feldspathic porcelain (VITABLOCS RealLife 1M1C, Vita Zahnfabrik) and 3Y-TZP zirconia (DD Bio ZW iso color, Dental Direkt), under the same conditions. The specimens were immersed in a mixture of toothpaste and deionized water and subjected to simulated toothbrushing tests following ISO/TR14569–1:2007. Tests were performed under 3.5 N load, 5 Hz frequency, and 10 mm stroke length. The toothbrush abrasion resistance of each tested material was evaluated through the specific wear rate. The surface roughness and color difference were assessed for all materials before and after 16 years of simulated toothbrushing tests. Statistical analysis was performed by applying one-way ANOVA. The results revealed that the surface characteristics of restorative dental materials were modified by the toothbrushing, except for zirconia. The polymer was the material more susceptible to toothbrushing wear, presenting the highest surface roughness, specific wear rate, and surface change. On the other hand, zirconia showed to be about 10 times more resistant to abrasion than feldspathic porcelain and composite and about 100 times more resistant than polymer. Thus, it is a promising solution for the promotion of longevity restorations.

Antibacterial properties and abrasion-stability: Development of a novel silver-compound material for orthodontic bracket application.

Bacteria-induced white spot lesions are a common side effect of modern orthodontic treatment. Therefore, there is aneed for novel orthodontic bracket materials with antibacterial properties that also resist long-term abrasion. The aim of this study was to investigate the abrasion-stable antibacterial properties of anewly developed, thoroughly silver-infiltrated material for orthodontic bracket application in an in situ experiment. To generate the novel material, silver was vacuum-infiltrated into asintered porous tungsten matrix. Atooth brushing simulation machine was used to perform abrasion equal to 2years of tooth brushing. The material was characterized by energy dispersive X‑ray (EDX) analysis and roughness measurement. To test for antibacterial properties in situ, individual occlusal splints equipped with specimens were worn intraorally by 12periodontal healthy patients for 48 h. After fluorescence staining, the quantitative biofilm volume and live/dead distribution of the initial biofilm formation were analyzed by confocal laser scanning microscopy (CLSM). Silver was infiltrated homogeneously throughout the tungsten matrix. Toothbrush abrasion only slightly reduced the material's thickness similar to conventional stainless steel bracket material and did not alter surface roughness. The new silver-modified material showed significantly reduced biofilm accumulation in situ. The effect was maintained even after abrasion. Apromising, novel silver-infiltrated abrasion-stable material for use as orthodontic brackets, which also exhibit strong antibacterial properties on in situ grown oral biofilms, was developed. The strong antibacterial properties were maintained even after surface abrasion simulated with long-term toothbrushing.

The Diagnosis & Management of Non-Carious Cervical Lesions by Dental Practitioners from the South Yorkshire and Bassetlaw Regions of England

A survey-based study, utilising qualitative and quantitative questions was used to investigate the diagnosis and the management of non-carious cervical lesions (NCCLs), including an overview to the working and gender demographics of primary dental care practitioners in South Yorkshire. To establish the contributing factors associated with NCCLs; to identify the most common approach used by dentists on how to manage NCCLs, and to identify what restorative materials dentists used and why. Objectives: To investigate, by the use of a questionnaire, the diagnosis &amp; management of non-carious cervical lesions by dental practitioners. Materials and Methods: A sample size calculation yielded a survey size of 149, following initial returns (non-responders) the questionnaire was posted to 300 randomly chosen participants. The questionnaire contained an initial demographic section to ascertain; gender, time since graduation and working times (8 questions), and the second section focused 6 questions upon; NCCL diagnosis, management and treatment options. Likert scale (5 point responses: greatly agree to greatly disagree), freetext boxes, closed-ended and multiple-choice questions were used to collect data from respondents. The response rate was (53.3%). Results: Abrasion, particularly tooth brushing, was believed to be the main cause of NCCLs (87%). An initial monitor/ preventative (fluoride application) approach was taken first, with the rationale to restore being based upon patient reported symptoms, first, and then followed by any aesthetic concerns/ preservation of tooth tissue. When NCCLs were being treated there was a wide range of numbers: modal value of 2, and median value of 5 NCCLs being restored per week. Composite was the aesthetic material of choice to restore NCCLs (57%), followed by (30%) for glass polyalkenoate (GI cements) restorations. Conclusion: Our demographic data indicated that the survey cohort could be considered as a representative sample of primary care dental practitioners in terms; of gender, time since qualification (as a proxy of age), and working practice (NHS vs. Private), and sessions worked per week. There was a strong agreement between dentists that tooth brushing abrasion is the main causes of NCCLs., and while the majority of NCCLs are managed conservatively, composite is the most frequent restorative material used by dentists to restore NCCLs followed by GIC. Dentists are more likely to restore NCCLs to improve sensitivity or to preserve remaining tooth structure, than to improve patients’ aesthetics. The size of the cavity, the anatomical position of the tooth, the nature of the cause, the aesthetic consideration and the materials’ technical properties had an effect on deciding the choice of restorative material.

Development and maintenance of surface gloss of dental composites after polishing and brushing: Review of the literature.

To describe the effect of the composites' composition to produce high surface smoothness/gloss using finishers/polishers, and to assess maintained smoothness/gloss under toothbrush abrasion. PubMed papers published from January 01, 2000 to September 01, 2021 were included, and keywords used were: filler particle size, shape, amount of dental composites; finishing/polishing, gloss/roughness, and toothbrush abrasion of composites. Seventy-five in-vitro studies were included in this literature review. Forty-six articles assessed filler particle size/composition/shape and distribution to obtain high gloss/smoothness on different formulations; and the finishers/polishers effect on these materials. Twenty-nine papers assessed toothbrush abrasion of composites. Suprananofill/nanofill/microfills typically showed the smoothest and glossiest surfaces compared to nanohybrid, microhybrid and hybrid composites. Microfill (0.04-0.07 μm, 71-88 GU); suprananofill (0.001-0.8μm, 52-92 GU), microhybrids (0.05-0.35μm, 35-95 GU) and nanohybrids (0.05-0.21μm, 66-97 GU). Composites with small, spherical particles tend to show smoother, glossier surfaces and more wear resistant compared to resin composites with larger or irregular particles. Several studies showed higher roughness and reduced gloss after toothbrush abrasion. Within the limitations of this study, suprananofill/nanofill/microfill composites tended to show the smoothest/glossiest surfaces due to smaller particle size. Composites with small, spherical particles tended to show smoother/glossier surfaces. Overall, toothbrush abrasion showed higher surface roughness and reduced gloss. Suprananofills/nanofills/microfills had good polishability and polish retention due to their smaller particle size. The effectiveness of a polishing system is material-dependent. In general, Enhance-PoGo, Sof-Lex discs, and Sof-Lex Spiral wheels showed similar level of smoothness.

Effect of tooth brush abrasion on the color, gloss and surface roughness of internally and externally stained monolithic ceramic materials.

To measure the durability of the color, change in surface roughness and gloss of stained monolithic ceramic materials subjected to artificial tooth brush abrasion. Standardized specimens were manufactured from pressable lithium-disilicate glass ceramic (PC; IPS e.max Press), machinable lithium-disilicate glass ceramic (MC; IPS e.max CAD), and zirconia (ZR; Zenostar). Ceramic staining was applied before (internal; in) and after crystallization/sintering (external; ex). Of each ceramic material, specimens without staining were prepared (no staining; no). Porcelain-fused-to-metal specimens served as control (PFM). Each group consisted of 15 specimens. Tooth brushing was simulated with tooth brushing strokes of 21.6 k, 43.2 k, and 64.8 k. Color, gloss and roughness were measured at baseline and after cycle intervals. Kruskal-Wallis and paired Post-hoc Conover tests were applied to detect statistical differences between treatment groups. Differences before and after aging were calculated by Wilcoxon signed rank test (α=0.05). In all groups, color difference (∆E) was statistically significant after aging: no-PC (P<.001, 95% CI[0.14,0.84]), no-MC (P=.003, 95% CI[0.23,1.12]), no-ZR (P=.003, 95% CI[0.33,0.62]), in-MC (P=.003, 95% CI[0.35,0.73]), in-ZR (P=.003, 95% CI[0.09,0.32]), ex-PC (P=.003, 95% CI[0.54,0.98]), ex-MC (P<.001, 95% CI[0.23,1.26]), ex-ZR (P=.003, 95% CI[0.27,0.55]), and PFM (P=.002, 95% CI[0.22,0.34]). Aging increased surface roughness and decreased the gloss within all subgroups showing statistical significance. Color, gloss and roughness of stained monolithic ceramic materials changed significantly by means of tooth brush abrasion in vitro. Color changes were below the threshold value for the detection by the human eye (∆E 1.8).

63 - Aesthetic Properties of New Hybrid Resin Block for CAD/CAM

Hybrid resin block for CAD/CAM are known as useful material for clinical use. In last year, hybrid resin crown for CAD/CAM restoration in anterior teeth was approved by Japanese national health insurance. Recently we launched highly aesthetic resin block CERASMART LAYER only in Japan. CERASMART LAYER can materialize an aesthetic appearance close to natural teeth because it has three-layered composition. The purpose of this study was to evaluate aesthetic properties of the new material and other products in the marketplace. Five materials were selected for experimental and analysis, 1) CERASMART LAYER (GC Corp.), 2) KATANA AVENCIA N (Kuraray), 3) KZR-CAD HR Block4 E-VA (YAMAKIN), 4) HC HARD AN (SHOFU), 5) ENAMIC Multicolor (VITA). These blocks were evaluated by Tooth-brush test. The specimen of tooth-brush test was formed into anterior teeth shape by using Cerec inLab MC XL (Dentsply Sirona) and was recontoured and polished in accordance with instructions. The specimen was placed in silicone mold in order to define the position of abrasion by brush. The test was conducted with tooth-brush machine for 12,000 cycles. The surface morphology of specimens before and after test was investigated with laser microscope (KEYENCE) and evaluated surface roughness (Ra value). All results were analyzed by one-way ANOVA (p<0.05). The results of tooth-brush test, CERASMART LAYER showed the lowest Ra value after 12,000 cycles of tooth-brush abrasion because of uniformly dispersion and high loading of inorganic nano-filler. In addition, only CERASMART LAYER and KATANA AVENCIA N showed glossy surface in spite of after 12,000 cycles of tooth-brush test. From the results, CERASMART LAYER exhibited the lowest surface roughness and highly gloss retention. Therefore, it is expected that CERASMART LAYER is a durable and aesthetic material and may have clinical advantages.