scholarly journals Effects of desensitizing dentifrices on dentin tubule occlusion and resistance to erosive challenges

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xiaoyi Zhao ◽  
Lin Wang ◽  
Jie Pan ◽  
Hans Malmstrom ◽  
Yan-Fang Ren
Keyword(s):  
Cross Sections ◽  
Orange Juice ◽  
Laser Scanning ◽  
Artificial Saliva ◽  
Disk Surface ◽  
Dentin Tubule ◽  
Dentin Tubules ◽  
Casein Phosphopeptide ◽  
Polyvinyl Methyl Ether ◽  
Tubule Occlusion

Abstract Background Many studies have demonstrated efficacy of casein phosphopeptide (CPP) containing products for dentin tubule occlusion for treatment of dentin sensitivity, but their effectiveness under dynamic erosive challenges remains to be elucidated. The purpose of the present study was to investigate the effectiveness of a desensitizing dentifrice containing CPP in occluding dentin tubules and resisting erosive challenges in comparison to that containing polyvinyl methyl ether/maleic acid (PVM/MA) copolymers. Methods A total of 33 dentin discs were prepared from coronal sections of human third molars and divided into 3 groups: a toothpaste containing CPP; a toothpaste containing PVM/MA and submicron silica; and a regular toothpaste (Controls). A soft-bristle toothbrush was used to brush the dentin discs with the dentifrices for 45 strokes in 30 s at a force of approximately 200 g. The brushing cycle was repeated after immersion of the dentin discs in artificial saliva overnight. The dentin discs were then challenged in orange juice for 10 min in an incubator rocking at 120 rpm. Three fields were randomly selected on each dentin disk surface to assess dentin tubule occlusions after each brushing cycle and after orange juice challenge with a 3D laser scanning microscope. Specimen cross sections were examined with a scanning electron microscope equipped with energy dispersive spectroscopy (SEM/EDS). Results After the first and second cycles of brushing, dentin tubules were occluded on average by 56.3% and 85.7% in CPP group, 66.2% and 88.1% in PVM/MA group, and 0.0 and 13.0% in the controls, respectively. There were no statistically significant differences in dentin tubule occlusions between the CPP and PVM/MA groups after two cycles of brushing (p>0.05). After dynamic erosive challenges with orange juice, 20.3% of the dentin tubules in the CPP group, 79.1% in the PVM/MA group and none in the control remained occluded (P<0.05). SEM/EDS imaging showed that dentin tubules were blocked with plugs containing dentifrice substances in CPP and PVM/MA groups after treatments, but none in the controls. Conclusions Desensitizing dentifrices containing CPP or PVM/MA could effectively occlude dentin tubules after two cycles of brushing. PVM/MA in combination with submicron silicon dioxide exhibited stronger resistance to dynamic erosive challenges by acidic beverages. Inorganic fillers that can enter dentin tubules and resist erosive challenges may be key for desensitizing dentifrices.

In Vitro Effect of Innovative Desensitizing Agents on Dentin Tubule Occlusion and Erosive Wear

2019 ◽  
Vol 44 (2) ◽  
pp. 168-177 ◽  
Author(s):  
SA Garofalo ◽  
LO Sakae ◽  
AC Machado ◽  
SR Cunha ◽  
DM Zezell ◽  
...  
Keyword(s):  
Erosive Wear ◽  
Repeated Measure ◽  
Control Group ◽  
Dentin Hypersensitivity ◽  
Surface Loss ◽  
Dentin Tubule ◽  
Desensitizing Agents ◽  
Dentin Tubules ◽  
Vitro Effect ◽  
Tubule Occlusion

SUMMARY Purpose: The purpose of this study was to evaluate the effects of four in-office desensitizing products on dentin tubule occlusion and erosive wear. Methods: Dentin hypersensitivity was simulated by EDTA application for five minutes. The specimens were randomly allocated into five groups (n=11), according to treatment: No treatment - Control (C), Duraphat (DUR), Desensibilize Nano P (NP), ClinPro XT Varnish (XTV), and ClinPro White Varnish (CWV). They were then submitted to erosive/abrasive cycling for five days. After EDTA, treatment, and cycling, the specimens were analyzed with an environmental scanning electron microscope (ESEM) to verify the number of opened dentin tubules (ODT) which were counted by using ImageJ software, and with a profilometer to determine the surface curvature/loss. ESEM data were analyzed with two-way repeated measure analysis of variance and Tukey tests. For the profilometer, data were analyzed with Kruskal-Wallis, Tukey, and Mann-Whitney tests. Results: After treatment, all groups showed lower ODT than the control, without significant differences between them. After cycling, the only group that showed lower ODT than the control was group XTV; however, it did not significantly differ from the other groups. For the profilometric analysis, there were significant differences in SL between the experimental times after treatment and after cycling for all groups (p&lt;0.05). After cycling, no surface loss was detected in groups DUR and XTV, which presented a significantly different curvature than group NP and the control group, but not from group CWV. Surface loss was detected for the control and groups NP and CWV, without difference among them. Conclusion: All desensitizing agents tested presented promising results concerning the obliteration of dentin tubules immediately after treatment. XTV was the only desensitizer capable of preventing the reopening of the tubules after the erosive/abrasive challenges. XTV and DUR presented a protective effect against dentin erosive wear.

scholarly journals Sequential Application of Calcium Phosphate and ε-Polylysine Show Antibacterial and Dentin Tubule Occluding Effects In Vitro

2021 ◽  
Vol 22 (19) ◽  
pp. 10681
Author(s):  
Shinechimeg Dima ◽  
Hsiao-Ting Huang ◽  
Ikki Watanabe ◽  
Yu-Hua Pan ◽  
Yin-Yin Lee ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Artificial Saliva ◽  
Brain Heart Infusion ◽  
Bacterial Suspension ◽  
Antibacterial Effects ◽  
Dentinal Tubules ◽  
Dentin Tubule ◽  
Tubule Occlusion ◽  
Calcium Phosphate Precipitation

In this study, ε-polylysine and calcium phosphate precipitation (CPP) methods were employed to induce antibacterial effects and dentin tubule occlusion. Antibacterial effects of ε-polylysine were evaluated with broth dilution assay against P. gingivalis. CPP solution from MCPM, DCPD, and TTCP was prepared. Four concentrations of ε-polylysine(ε-PL) solutions (0.125%, 0.25%, 0.5%, 1%) were prepared. Dentin discs were prepared from recently extracted human third molars. Dentin discs were incubated with P. gingivalis (ATCC 33277) bacterial suspension (ca. 105 bacteria) containing Brain Heart Infusion medium supplemented with 0.1 g/mL Vitamin K, 0.5 mg/mL hemin, 0.4 g/mL L-cysteine in anaerobic jars (37 °C) for 7 days to allow for biofilm formation. P. g–infected dentin specimens were randomly divided into four groups: CPP + 0.125% ε-PL, CPP + 0.25% ε-PL, CPP + 0.5% ε-PL, CPP + 1% ε-PL. On each dentin specimen, CPP solution was applied followed by polylysine solution with microbrush and immersed in artificial saliva. Precipitate formation, antibacterial effects, and occlusion of dentinal tubules were characterized in vitro over up to 72 h using scanning electron microscopy. ε-PL showed 34.97% to 61.19% growth inhibition levels against P. gingivalis(P. g) after 24 h of incubation. On P. g-infected dentin specimens, DCPD + 0.25% ε-PL, and DCPD + 0.5% ε-PL groups showed complete bacterial inhibition and 78.6% and 98.1% dentin tubule occlusion, respectively (p < 0.001). The longitudinal analysis on fractured dentin samples in DCPD and TTCP groups revealed deeply penetrated hydroxyapatite-like crystal formations in dentinal tubules after 72 h of incubation in artificial saliva.

scholarly journals Nanotubular Oxide Layer Formed on Helix Surfaces of Dental Screw Implants

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 115 ◽  
Author(s):  
Magdalena Jażdżewska ◽  
Michał Bartmański
Keyword(s):  
Oxide Layer ◽  
Cross Sections ◽  
Surface Coverage ◽  
Artificial Saliva ◽  
Corrosion Current ◽  
Optical Microscope ◽  
Significant Difference ◽  
Helix Surfaces ◽  
Future Work ◽  
Oxidation Parameters

Surface modification is used to extend the life of implants. To increase the corrosion resistance and improve the biocompatibility of metal implant materials, oxidation of the Ti-13Nb-13Zr titanium alloy was used. The samples used for the research had the shape of a helix with a metric thread, with their geometry imitating a dental implant. The oxide layer was produced by a standard electrochemical method in an environment of 1M H3PO4 + 0.3% HF for 20 min, at a constant voltage of 30 V. The oxidized samples were analyzed with a scanning electron microscope. Nanotubular oxide layers with internal diameters of 30–80 nm were found. An analysis of the surface topography was performed using an optical microscope, and the Sa parameter was determined for the top of the helix and for the bottom, where a significant difference in value was observed. The presence of the modification layer, visible at the bottom of the helix, was confirmed by analyzing the sample cross-sections using computed tomography. Corrosion tests performed in the artificial saliva solution demonstrated higher corrosion current and less noble corrosion potential due to incomplete surface coverage and pitting. Necessary improved oxidation parameters will be applied in future work.

A Practical Computing Method for Residual Area of Rebar Cross-Sections under Carbonation Induced Corrosion

2012 ◽  
Vol 166-169 ◽  
pp. 1895-1899
Author(s):  
Xiao Gang Wang ◽  
De Ming Zhong
Keyword(s):  
Cross Sections ◽  
Laser Scanning ◽  
Major Axis ◽  
Structural Deterioration ◽  
Minimum Residual ◽  
Degree Of Confidence ◽  
Conservative Approximation ◽  
Rc Slabs ◽  
Computing Method ◽  
Geometric Measurement

Area loss of severely weakened rebar cross sections is a crucial variable in assessment of structural deterioration for corroded concrete structures, which is hard to be measured or estimated precisely in conventional methods. In this paper, rebar samples were taken from naturally corroded RC slabs. Their virtual models were built using 3D laser scanning technique to facilitate geometric measurement. From these models seriously weakened sections were screened out as analyzing samples, and residual areas as well as profiles of the cross-sections were derived and investigated consequently. Shown by the results, corrosion was non-uniformly distributed on rebar surface, and profiles of the residual cross-sections can hardly be formulated efficiently. However, they can be simplified into ellipse with minor axis of minimum residual diameter and major axis of diameter in perpendicular direction. This model has been proved to give an conservative approximation of residual sectional area with 4.27% underestimation and 89.2% degree of confidence.

scholarly journals Surface and subsurface erosion of primary enamel by acid beverages over time

2010 ◽  
Vol 21 (4) ◽  
pp. 337-345 ◽  
Author(s):  
Carolina Paes Torres ◽  
Michelle Alexandra Chinelatti ◽  
Jaciara Miranda Gomes-Silva ◽  
Fátima Aparecida Rizóli ◽  
Maria Angélica Hueb de Menezes Oliveira ◽  
...  
Keyword(s):  
Exposure Time ◽  
Orange Juice ◽  
Artificial Saliva ◽  
Soft Drink ◽  
Sem Analysis ◽  
Surface Microhardness ◽  
Sem Images ◽  
Structural Loss ◽  
Group 2 ◽  
Similar Decrease

This study evaluated the influence of a cola-type soft drink and a soy-based orange juice on the surface and subsurface erosion of primary enamel, as a function of the exposure time. Seventy-five primary incisors were divided for microhardness test (n=45) or scanning electron microscopy (SEM) analysis (n=30). The specimens were randomly assigned to 3 groups: 1 - artificial saliva (control); 2 - cola-type soft drink; and 3 - soy-based orange juice. Immersion cycles in the beverages were undertaken under agitation for 5 min, 3 times a day, during 60 days. Surface microhardness was measured at 7, 15, 30, 45 and 60 days. After 60 days, specimens were bisected and subsurface microhardness was measured at 30, 60, 90, 120, 150 and 200 µm from the surface exposed. Data were analyzed by ANOVA and Tukey’s test (a=0.05). Groups 2 and 3 presented similar decrease of surface microhardness. Regarding subsurface microhardness, group 2 presented the lowest values. SEM images revealed that after 60 days the surfaces clearly exhibited structural loss, unlike those immersed in artificial saliva. It may be concluded that erosion of the surfaces exposed to the cola-type soft drink was more accentuated and directly proportional to the exposure time.

Triacrylamide-Based Adhesives Stabilize Bonds in Physiologic Conditions

2022 ◽  
pp. 002203452110617
Author(s):  
F.S. de Lucena ◽  
S.H. Lewis ◽  
A.P.P. Fugolin ◽  
A.Y. Furuse ◽  
J.L. Ferracane ◽  
...  
Keyword(s):  
Bond Strength ◽  
Cross Sections ◽  
Laser Scanning ◽  
Adhesive System ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Gap Formation ◽  
Bond Stability ◽  
Occlusal Surfaces ◽  
Before And After

In this study, an acrylamide-based adhesive was combined with a thiourethane-based composite to improve bond stability and reduce polymerization stress, respectively, of simulated composite restorations. The stability testing was conducted under physiologic conditions, combining mechanical and bacterial challenges. Urethane dimethacrylate was combined with a newly synthesized triacrylamide (TMAAEA) or HEMA (2-hydroxyethyl-methacrylate; control) to produce a 2-step total-etch adhesive system. Methacrylate-based composites (70 wt% silanized filler) were formulated, containing thiourethane oligomers at 0 (control) or 20 wt%. Standardized preparations in human third molars were restored; then, epoxy replicas were obtained from the occlusal surfaces before and after 7-d storage in water or with Streptococcus mutans biofilm, which was tested after storage in an incubator (static) or the bioreactor (mechanical challenge). Images were obtained from the replicas (scanning electron microscopy) and cross sections of the samples (confocal laser scanning microscopy) and then analyzed to obtain measurements of gap, bacterial infiltration, and demineralization. Microtensile bond strength of specimens stored in water or biofilm was assessed in 1-mm2 stick specimens. Data were analyzed with analysis of variance and Tukey’s test (α = 0.05). HEMA-based materials had greater initial gap measurements, indicating more efficient bonding for the acrylamide materials. When tested in water, the triacrylamide-based adhesive had smaller gaps in the incubator or bioreactor. In the presence of biofilm, there was less difference among materials, but the acrylamide/thiourethane combination led to statistically lower gap formation in the bioreactor. HEMA and TMAAEA-based adhesives produced statistically similar microtensile bond strengths after being stored in water for 7 d, but after the same period with biofilm-challenged specimens, the TMAAEA-based adhesives were the only ones to retain the initial bond strength values. The use of a stable multiacrylamide-based adhesive led to the preservation of the resin-dentin bonded interface after a physiologically relevant challenge. Future studies will include a multispecies biofilm model.

Analysis of Silicon Micromachining by UV Lasers, and Implications for Full Cut Laser Dicing of Ultra-Thin Semiconductor Device Wafers

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 001743-001759
Author(s):  
Andy Hooper ◽  
Daragh Finn
Keyword(s):  
Cross Sections ◽  
Laser Scanning ◽  
Semiconductor Device ◽  
Laser Pulses ◽  
Silicon Wafers ◽  
Silicon Devices ◽  
Laser Fluences ◽  
Slow Velocity ◽  
3D Packaging ◽  
Thin Silicon

3D packaging technologies such as FLASH rely on die-to-die stacking of ultra-thin silicon devices with individual die thicknesses below 100 um. Because ultra-thin silicon wafers are very fragile, mechanical saw dicing of sub 100 um thick wafers tends to be more challenging, requiring slower processing and reduced throughput and/or yields. These challenges make full cut laser dicing an attractive solution. This presentation provides an investigation for machining of 50 um thick silicon wafers using a Gaussian-shaped, nanosecond pulsewidth, 355 nm UV laser. A range of machining speeds and laser fluences are compared, from single laser pulses to highly overlapped slow-velocity machining. 3D Laser Scanning Microscope and FIB/TEM cross sections are employed to characterize the state and depth of heating damage into the Si material. Implications for laser machining rates and die break strength are investigated for full cut laser dicing.

A 3-Dimensional Model of the Human Round Window Membrane

2019 ◽  
Vol 128 (6_suppl) ◽  
pp. 103S-110S
Author(s):  
Yasuya Nomura ◽  
Toru Tanaka ◽  
Hitome Kobayashi ◽  
Yurika Kimura ◽  
Yurie Soejima ◽  
...  
Keyword(s):  
Cross Sections ◽  
Laser Scanning ◽  
Round Window ◽  
Gross Anatomy ◽  
Laser Scanning Microscopy ◽  
Round Window Membrane ◽  
Dimensional Model ◽  
Anterior Portion ◽  
Posterior Portion ◽  
3 Dimensional

Objectives: The round window membrane (RWM) is small in size, making it difficult to clarify its shape and structure. The authors examined a 40x magnified 3-dimensional model of the human RWM to clarify its morphologic aspects and characteristics. Methods: An RWM specimen was obtained from an archival, formalin-fixed, decalcified, left temporal bone of an 84-year-old female cadaver. The data obtained by laser scanning microscopy were input into a 3-dimensional printer. After a model of the RWM was created, the following features were examined: striae on the surfaces, curvatures, thickness, and areas. Cross sections of the original specimen were made for histological observations. Results: The contour of this RWM model was approximately elliptic, with a saddle shape. When illuminated from the scala tympani side, the surface facing the fossula exhibited dark anterior and clear posterior portions. A borderline appeared where the 2 portions were bound along the short axis of the ellipse. This borderline was identified as the line of inflection. Collagen fibers were shown to run parallel to the borderline in the posterior portion but were fanned out in the anterior portion. Conclusions: The magnified 3-dimensional model clarified gross anatomy and characteristics of the RWM. It is good teaching material for small tissues, such as the RWM.

Effect of Calcium-phosphate Desensitizers on Staining Susceptibility of Acid-eroded Enamel

2019 ◽  
Vol 44 (3) ◽  
pp. 281-288 ◽  
Author(s):  
KY Kyaw ◽  
M Otsuki ◽  
MS Segarra ◽  
N Hiraishi ◽  
J Tagami
Keyword(s):  
Surface Roughness ◽  
Calcium Phosphate ◽  
Repeated Measures ◽  
Laser Scanning ◽  
Artificial Saliva ◽  
Color Difference ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Control Group ◽  
Before And After

SUMMARY Objective: To investigate the effect of calcium-phosphate–based desensitizers, Teethmate AP paste (TMAP) and Teethmate Desensitizer (TMD) (Kuraray Noritake Dental, Tokyo, Japan), on the prevention of staining on acid-eroded enamel. Methods and Materials: Forty polished enamel samples (4×4×1 mm) from bovine incisors were randomly divided into five groups (n=8). After immersion in 50 mL of 0.5% citric acid (pH 2.5) for 15 minutes to form acid-eroded surfaces, the surfaces were subjected to different treatments with TMAP, TMD, and NaF (0.21% means 950 ppm) for five minutes. Another eroded group was not treated with desensitizer. For the control group, the samples were not eroded or treated. All the samples were stored in artificial saliva (AS) at pH 7.2 for 24 hours at 37°C. The TMAP, TMD, or NaF was reapplied at eight and 16 hours during the 24 hours of storage time. The surface roughness (Sa) was evaluated following ISO 25178 for surface texture using confocal laser scanning microscopy (VK-X 150 series, Keyence, Osaka, Japan) before acid erosion, after acid erosion, and after 24 hours of incubation in AS. Afterward, the color difference was measured with a dental colorimeter (Shade Eye NCC, Shofu, Kyoto, Japan) before and after staining with tea solution. Results: One-way repeated measures analysis of variance showed that acid erosion significantly increased Sa (p&lt;0.001). TMAP- and TMD-treated groups exhibited lower Sa values than the NaF group and the no-desensitizer treatment group. The greatest staining was observed in the NaF group and the no-desensitizer group, while the TMAP and TMD groups significantly decreased the formation of stains. Conclusions: Acid-eroded enamel increased surface roughness and tended to absorb more stains. However, the application of TMAP and TMD moderated the roughness and thus prevented the formation of extrinsic stains.

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