Micromorphological evaluation of dentin treated with different desensitizing agents (original) (raw)
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Brazilian Dental Journal, 2002
This is a preliminary study to determine a methodological sequence in vitro which may allow the reproduction of dentin for SEM analysis, after the use of different desensitizing agents. Dentin discs obtained from extracted human third molars were etched with 6% citric acid, an artificial smear layer was created and the surface dentin discs were divided into four quadrants. Quadrants 2, 3 and 4 of each disc were conditioned with 6% citric acid. The desensitizing agents (Oxa-Gel ® , Gluma Desensitizer and an experimental agent) were applied to quadrants 3 and 4. To evaluate the acid resistance of the treatment, quadrant 4 was etched again with 6% citric acid. An impression was then taken with Aquasil ULV. After a setting period of 6 min, each disc was removed from the impression and stored in a moist-free environment for 24 h at 37 o C. After that time, a low-viscosity epoxy resin (Araltec GY 1109 BR) was poured into the impression and cured for 24 h. All specimens were metal-coated for SEM analysis. Comparison of the photomicrographs of dentin discs with their respective impressions and resin replicas showed that this technique can reproduce the characteristics of the dentin surface treated with desensitizing agents.
Revista Portuguesa de Estomatologia, Medicina Dentária e Cirurgia Maxilofacial, 2017
To evaluate dentin tubule obliteration after application of two different desensitizing toothpastes using scanning electron microscopy (SEM) for ultramorphological analysis and energy dispersive X-ray spectroscopy (EDX) for chemical evaluation. Methods: Five dentin discs were sectioned into four quarters; surfaces were etched with 6% citric acid for 2 minutes and equally distributed into four groups. In G1 (control) no treatment was performed; dentin surfaces were brushed twice-daily during 14 days with artificial saliva (G2), a combined stabilized stannous fluoride, sodium hexametaphosphate and silica (SFSH) toothpaste (G3) and a calcium sodium phosphosilicate (CSFS) toothpaste (G4), under a standardized protocol. All specimens were analyzed by SEM and EDX and tubule occlusion was scored. Statistical analysis was performed using Kruskal-Wallis (p<0.05). Results: Score distribution across groups consistently increased from G1 to G4, being the last the most consistent group. Statistical between-treatment comparisons for 750-fold and 2000-fold magnification revealed significant differences between groups (p=0.009 and p=0.002, respectively). For both magnifications, post-hoc analysis adjusted for multiple comparisons only indicated statistically significant differences between G1 and G4 (p=0.012 and p=0.001, respectively). Chemical analysis revealed high levels of carbon, oxygen and nitrogen for G1. For G2 an increase of the levels of the phosphorous and calcium elements and a drop of oxygen and carbon levels was registered. G3 and G4 showed a surface layer mainly composed of calcium and phosphorous. Conclusions: Both desensitizing toothpastes induced high levels of tubule occlusion with consistent phosphorus and calcium deposition over dentin surface.
Effect of antimicrobial agents on the micromorphology of primary dentin
Journal of Clinical Pediatric Dentistry, 2002
The use of disinfectants on the dentin surface contributes to superficial cleaning and removal of remaining microorganisms of the carious process. However, the effect of these agents on the adhesion of resin materials to the dentin surface of primary teeth has not been established. This study evaluated the dentin micromorphological effects due to the use of antimicrobial agents in the different depths of dentin. Twenty-five buccal surfaces of primary molars were prepared from the sectioned teeth, ground flat and polished with silicon carbide paper of different grits. The surfaces were treated with 32% phosphoric acid with benzalkonium chloride (Bisco), 35% phosphoric acid gel (3M), 3% benzalkonium chloride solution by itself or 10% maleic acid. All agents were applied for 15 seconds on the dentin surface. The samples were washed with distilled water, dried and coated with gold for observation of the dentin surface with the scanning electron microscope. The samples were subdivided ac...
Journal of Hard Tissue Biology
In the treatment of dentin hypersensitivity accompanying tooth substance defects such as wedge-shape defects, hypoesthesia can be achieved by applying a desensitizing agent before carrying out restoration using resin composite. However, almost no research has investigated the adhesion of resin to dentin coated with the latest desensitizing agents. Therefore, this study investigated the effects of various desensitizing agents on the adhesion of resin to dentin in combination with a 1-step self-etch system by using a hypersensitive dentin model in which the dentinal tubules were opened without etching and there was almost no smear layer on the intertubular dentin. Specimens with a #4000 polished dentin flat surface were ultrasonically cleaned for 60 min (15 min × 4 times). Then, the bond strength, failure modes, and micromorphology of surfaces coated with desensitizing agent to which resin was bonded immediately afterward and surfaces coated with desensitizing agent to which the resin was bonded after storage for 7 days in water were compared against a control to which no desensitizing agent was applied. The desensitizing agents used in this research did not promote adhesion of the resin immediately after application, but rather suppressed or completely obstructed it. Although deposits of microparticles and thin film material, which were observed immediately after application, tended to disappear after 7 days of storage in water, some of the desensitizing agents exhibited the same bond strength as the control, whereas other desensitizing agents did not show recovery of adhesion strength. Therefore, care is required when performing resin restoration immediately after application of a desensitizing agent, depending on the agent used, and caution must be exercised in the selection of desensitizing agents in the clinical setting.
Journal of IMAB - Annual Proceeding (Scientific Papers), 2016
Aim: to compare micromorphological changes in primary and permanent dentin after etching with phosphoric acid (20% and 37,5%) for 7 and 15 sec. by SEM. Material and methods: The study included 42 primary and permanent teeth, divided into 8 groups by etching time and acid concentration. Enamel and dentin were removed from the vestibular area and after the expiration of etching time samples were washed with water-air stream and dried with light airflow. From each sample 10 magnified images were made from central vestibular area. The cleaning effect was measured in percentage, as a ratio between the number of uncleaned tubules to the total tubules. Results were analyzed with One-way and MANOVA. Post hoc Multiple Comparisons test-SPSS 19 was applied. Results: The proportion of uncleaned tubules in primary teeth was higher than that of permanent teeth at acid concentration of 20%. At a concentration of 37.5% this relationship is reversed. At 7 sec there was a bigger difference between the share of uncleaned tubules for primary and permanent teeth, while at 15 sec this difference virtually disappears. The difference in the proportion of uncleaned tubules between the two acid concentrations at 7 seconds etching is significantly greater compared to the same difference between the two acid concentrations by etching for 15 sec. Conclusion: Effectively removed smear layer and no precipitate was observed in primary teeth even at 7 seconds etching with 37.5% acid.
Evaluation of Dentinal Changes Following Application of Three Different Desensitizing Agents
Revista de Chimie, 2017
The aim of this in vitro study was to evaluate the effect of three desensitizing tooth pastes on the dentinal tubule occlusion. Thirty dentin discs having a thickness of 3 mm were obtained by cutting human teeth. The discs were submersed in citric acid for 30 seconds to open the dentin tubules. Then the discs were cut in two halves. In each group 10 halves were kept in 0.9% NaCl solution) and the other 10 halves were exposed to the action of one of the tested desensitizing toothpastes. The dentin samples were placed in the machine designed to simulate tooth brushing. Three commercial desensitizing toothpastes were chosen to be applied on dentin surface. The morphology of dentin samples and the level of tubule occlusion was scored using scanning electron microscope. All the three desensitizing toothpastes demonstrated significant effects on dentinal tubule occlusion. The tooth paste containing arginine and calcium carbonate as active ingredients showed the highest degree of tubule oc...
Journal of Biomedical Materials Research Part B: Applied Biomaterials, 2005
The aim of this study was to evaluate the microtensile bond strength (TBS) and the elemental contents of the adhesive interface created to normal versus caries-affected dentin. Extracted human molars with coronal carious lesions were used in this study. A self-etching primer/adhesive system (Clearfil Protect Bond) was applied to flat dentin surfaces with normal and caries-affected dentin according to the manufacturer's instructions. After 24 h water storage, the bonded specimens were cross-sectioned and subjected to a TBS test and electron probe microanalysis for the elemental distributions [calcium (Ca), phosphorus (P), magnesium (Mg), and nitrogen (N)] of the resin-dentin interface after gold sputtercoating. The TBS to caries-affected dentin was lower than that of normal dentin. The demineralized zone of the caries-affected dentin-resin interface was thicker than that of normal dentin (approximately 3 m thick in normal dentin; 8 m thick in caries-affected dentin), and Ca and P in both types of dentin gradually increased from the interface to the underlying dentin. The caries-affected dentin had lost most of its Mg content. The distributions of the minerals, Ca, P, and Mg, at the adhesive interface to caries-affected dentin were different from normal dentin. Moreover, a N peak, which was considered to be the collagenrich zone resulting from incomplete resin infiltration of exposed collagen, was observed to be thicker within the demineralized zone of caries-affected dentin compared with normal dentin.
Characterization of Fluorotic Enamel After Microabrasion and Desensitizing Agent
Introduction. Enamel microabrasion is a procedure used for removing a superficial layer of enamel that has some alteration of color and/or texture caused by dental fluorosis. The purpose of this study was to compare the microhardness and micromorphology of the fluorotic enamel surface after microabrasion with 6.6% hydrochloric acid and silica or 18% hydrochloric acid and evaluate the effect of desensitizing agent exposure on the treated enamel. Materials and Methods. Twenty anterior teeth with moderate fluorosis were divided into two groups: 1) Perla-Dent® group and 2) Opalustre® group. Each buccal surface of incisors was sectioned to obtain samples 3x3 mm. The samples were then mounted in acrylic blocks. The enamel surface of the blocks was polished, after the microabrasion materials and desensitizing agent were applied according to the manufacturer's instructions. All samples were analyzed by Vickers microhardness tester and scanning electron microscopy (SEM). Results. Both experimental groups presented a decrease in the microhardness values, with statistically significant differences (p<0.0001) when comparing the baseline and after treatments values. To compare the microhardness values after both microabrasion and desensitizing treatment in the study groups, it was observed that the Perla-Dent® group obtained lower values than the Opalescence® group with a statistically significant difference (p<0.0001). The representative images of study groups in SEM showed the enamel surface morphology after Perla-Dent® treatment more irregular and a very marked relief than that observed in enamel surface morphology after Opalustre® treatment. Conclusion. The surface of the enamel was more affected with Perla-Dent® treatment than with Opalustre® treatment and the placement of UltraEz® agent does not recover its baseline microhardness.
Brazilian Dental Journal
The aim of this study was to evaluate the influence of an extended use of desensitizing toothpastes (DTs) on dentin bonding, microhardness and roughness. One hundred and twenty bovine incisor teeth were randomly divided into four groups: G1, distilled water (WATER); G2, Colgate Total 12 (CT12); G3, Colgate Sensitive Pro-Relief (CSPR); and G4, Sensodyne Repair ?αμπ; Protect (SRP). Dentin surfaces were etched with 17% EDTA and 2 years of simulated tooth brushing (20,000 cycles) was performed on their surfaces. Knoop microhardness, surface roughness and scanning electron microscopy (SEM) were performed before and after the simulated tooth brushing. For microshear bonding test, a 2-step self-etching adhesive system (Clearfil SE Bond) was used and 0.8 mm diameter composite resin (Filtek Z350 XT) cylinders were built. Microshear test was performed with an orthodontic wire and with a crosshead speed of 0.5 mm/min. The data were analyzed for: 1) bond strength (one-way ANOVA), 2) microhardne...