Erosive Cycles Research Articles

Effect of black tea and matrix metalloproteinase inhibitors on eroded dentin in situ.

Purpose of this in situ study was to evaluate the surface properties of eroded dentin specimens activated with three different matrix metalloproteinase (MMP) inhibitors (chlorhexidine [CHX], fluoride, green tea), black tea, and water. One hundred eighty dentin samples were prepared from extracted third molars and then samples divided into six groups. Ten volunteers were carried three specimens of each group, on acrylic palatal appliances, which were fabricated exactly for them (n = 3). Erosive cycles were done by immersing appliances in cup containing Cola and was followed by rinsing with test solutions. Microhardness values were measured. Surface properties were investigated by atomic force microscopy (AFM). Lowest change in microhardness was shown in fluoride group whereas negative control group (water) had the highest change. There were no statistically significant differences among surface roughness changes (p > .05). The least change in microhardness was seen in the fluoride group (13.05 ± 8.07), while the control group showed the highest change (33.80 ± 12.42) and was statistically significant when compared to other groups (p < .05). Besides lowest depth, values were shown in fluoride group as well. AFM evaluations showed macromolecular deposits on surfaces of fluoride, CHX, and black tea groups. No superior results were detected in CHX + fluoride group and black tea showed similar surface characteristics as green tea. Mouthrinses containing not only green tea but also black tea could be beneficial for patients with exposed dentin surfaces. Catechines and theaflavins in teas could be useful for improving surface quality.

The effect of CO2 9.3μm short-pulsed laser irradiation in enamel erosion reduction with and without fluoride applications-a randomized, controlled in vitro study.

The aim of this in vitro study was to evaluate the protective effect of short-pulsed CO2 9.3μm laser irradiation against erosion in human enamel without and combined with TiF4 and AmF/NaF/SnCl2 applications, respectively, as well as compared to the protective effect of these fluoride treatments alone. After polishing, ninety enamel samples (3 × 3mm) were used for 9 different treatment groups: 4% TiF4 gel (pH1.5, 24,533ppmF-); AmF/NaF/SnCl2 rinse (pH4.5; 500ppmF-, 800ppm Sn2); CO2 laser (average power 0.58W); CO2 laser (0.58W) + TiF4; CO2 laser (0.58W) + AmF/NaF/SnCl2; CO2 laser (0.69W); CO2 laser (0.69W) + TiF4; CO2 laser (0.69W) + AmF/NaF/SnCl2; negative control (deionized water). TiF4 gel was brushed on only once before the first erosive cycling, while samples treated with AmF/NaF/SnCl2 were daily immersed in 5ml of the solution before cycling. Laser treatment occurred with a CO2 laser (wavelength 9.3μm, pulse repetition rate 100Hz, pulse duration 14.6μs/18μs, average power 0.58W/0.69W, fluence 1.9J/cm2/2.2J/cm2, beam diameter 0.63mm, irradiation time 10s, air cooling). TiF4 was applied only once, while AmF/NaF/SnCl2 was applied once daily before the erosive challenge. Surface loss (in μm) was measured with optical profilometry immediately after treatment, and after 5 and 10days of erosive cycling (0.5% citric acid, pH2.3, 6 × 2min/day). Additionally, scanning electron microscopy investigations were performed. All application measures resulted in loss of surface height immediately after treatment. After 5days, significantly reduced surface loss was observed after applying laser irradiation (both power settings) followed by applications of TiF4 or AmF/NaF/SnCl2 solution (p < 0.05; 2-way ANOVA and Tukey test) compared to fluoride application alone. After 10days, compared to after 5days, a reduced tissue loss was observed in all groups treated with AmF/NaF/SnCl2 solution. This tissue gain occurred with the AmF/NaF/SnCl2 application alone and was significantly higher when the application was combined with the laser use (p < 0.05). Short-pulsed CO2 9.3μm laser irradiation followed by additional application of AmF/NaF/SnCl2 solution significantly reduces the progression of dental enamel erosion in vitro.

Use of new scratch test and tensile test for evaluation of bond strength of selfadhesive flowable resin composite for repair of artificial tooth erosion

The purpose of this study was to use a new scratch test and tensile test to evaluate the bond strength between artificial erosive enamel or dentin and self-adhesive resin composites as a coating material. Coronal enamel or dentin surface was exposed to an erosive cycle (artificial saliva [AS], pH:7.0 for 6.5 h and acidic carbonated beverages for 5 min, alternated 3 times per day) for the eroded-surface or stored in AS for the remineralized-surface. Two self-adhesive flowable resin composites, Fusio and LLB-CR6 (prototype), and a conventional flowable resin composite, BEAUTIFIL FLOW with self-etching primer system, Clearfil Mega Bond, were applied to enamel or dentin surfaces; and then the bond strengths were measured. For the eroded-surface, there were no significant differences in bonding strength among all materials, as assessed by the new scratch test. Thus, these self-adhesive flowable resin composites might be useful for coating materials on acid-eroded tooth surfaces.

In situ effect of a proanthocyanidin mouthrinse on dentin subjected to erosion.

Proanthocyanidin has been shown to be efficient in inhibiting matrix metalloproteinases. The aim of this in situ study was to evaluate the protective effect of Proanthocyanidin-based mouthrinses either with naturally acidic or with a neutral pH applied on dentin subjected to erosion. Eight volunteers wore one palatal device in two phases (7 days washout) with 16 samples per group (n=8). The groups under study were: First Phase/ G1 - 10% proanthocyanidin mouthrinse (pH 7.0, Experimental group 1 - Purified Grape Seeds Oligomeric Proanthocyanidins), G2 - 10% proanthocyanidin mouthrinse (pH 3.0, Experimental group 2 - Purified Grape Seeds Oligomeric Proanthocyanidins). Second Phase/ G3 - 0.12% chlorhexidine mouthrinse (pH 7.0, Positive control group), G4 - no previous treatment (Negative control group). Each device was subjected to 3 erosive cycles (5 minutes) per day for 5 days. Treatments with different mouthrinses were applied once after the second erosive challenge (5 minutes). Profilometry was used to quantify dentin loss (µm). Data were analyzed by repeated measures of ANOVA followed by Fisher's test (p<0.05). G1 (1.17±0.69) and G3 (1.22±0.25) showed significantly lower wear values with no statistical difference between them. G2 (2.99±1.15) and G4 (2.29±1.13) presented higher wear values with no significant differences between them. The 10% proanthocyanidin mouthrinse (pH 7.0) could be a good strategy to reduce dentin wear progression.

Comparative Evaluation of Casein Phosphopeptide&amp;ndash;Amorphous Calcium Phosphate&amp;ndash;Fluoride Paste and Sodium Fluoride Mouthwash in the Prevention of Dental Erosion: An In Vitro Study

To compare the efficacy of casein phosphopeptide-amorphous calcium phosphate-fluoride (CPP-ACP-F) paste and 0.2% sodium fluoride mouthwash in the prevention of dental erosion using profilometer. The buccal surfaces of 36 premolar sound teeth were ground and polished to achieve a flat surface with silicone disks. Samples were allocated in three groups randomly. Group I was pretreated for 5 days four times a day with CPP-ACP-F paste. Group II was pretreated for 5 days with 0.2% sodium fluoride mouthwash four times a day. Group III remained as the control group without any pretreatment. In the next step, all the samples were exposed four times a day for 3 days to carbonated beverages. The samples were rinsed with saline after each erosive cycle and stored in artificial saliva. The profilometer was used to determine the surface loss. The data collected were evaluated using one-way analysis of variance (ANOVA) along with post hoc test. The erosion of group I (CPP-ACP-F paste) and group II (0.2% sodium fluoride mouthwash) was significantly less than that of group III (control group). The erosion in group II was significantly lower than in group I. Both sodium fluoride mouthwash and CPP-ACP-F paste are effective in the prevention of dental erosion. Sodium fluoride mouthwash shows higher reduction in dental erosion when compared with CPP-ACP-F paste. This study contributes to the understanding of the efficacy of CPP-ACP-F paste and 0.2% sodium fluoride mouthwash in the prevention of dental erosion.

The effect of gastric acid on chitosan modified glass ionomer cement: SEM-EDS.

This study aimed to use scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) to examine the elements that passed into the gastric acid solution after the application of a gastric acid erosive cycle to chitosan modified glass ionomer cement (GIC). Chitosan modified GIC samples were obtained by adding chitosan (vol/vol) of 5 and 10% to GIC for the experimental groups. These two experimental groups and a control group were subjected to gastric acid erosive treatment for 60 s six times a day for 10 days. The sample surfaces were coated with approximately 1 nm of gold to increase conductivity with the Q 150R ES device (Quorum Technologies, East Sussex, England). Surface topography images were obtained with a SEM. Besides, EDS analysis was also determined the number of elements graphically in the region where the fast electron beam hit. In the samples examined, the amount of element was determined. After gastric acid application, cracks and voids were observed on the surfaces of the samples. In the EDS analysis of the 5 and 10% chitosan modified GIC and control groups, Si, Al, Na, and F was found. It is necessary to investigate the antibacterial properties and physical properties of chitosan modified glass ionomer-free elements and fluorine ions using advanced techniques.

Effect of Dentin Conditioning and Erosive Coca Cola Challenge on the Micro-shear Bond Strength and SEM Evaluation of Resin-Modified Glass-Ionomer Cement- in vitro study

Objective: This study was designed to evaluate the role of an erosive beverage, Coca cola, on the microshear bond strength of a nano-fill resin modified glass-ionomer cement to dentin, after different conditioning protocols, no conditioning, GC conditioner and KN primer. Materials and Methods: The occlusal enamel of forty two third molar teeth was removed, exposing the coronal dentin. Thirty prepared teeth were randomly divided into three main groups (n=10). Group 1, flat dentin surface was left unconditioned (control). Group 2, GC cavity conditioner was applied. Group 3, Ketac Nano Primer was applied. Three pieces were cut from a polyethylene micro-bore tygon tube, for each specimen. KN resin modified glass ionomer cement was applied. Each group was further distributed into two subgroups (n=5). Subgroup i, teeth were immersed in artificial saliva (control). Subgroup ii, teeth were subjected to Coca Cola pH cycles. Each specimen was stressed in shear using a load cell of 5 KN at a crosshead speed of 0.5 mm/min. The remaining 12 teeth were divided according to the previously mentioned grouping system, and observed using SEM. Results: The data collected for µSBS were subjected to two-way ANOVA test, followed by Tukey’s post hoc test. Considering the dentin conditioning factor, with storage in artificial saliva; the control group revealed the least µSBS values, followed by the group conditioned with KNP and GC conditioning, respectively. Control group posses a significant decrease in the µSBS compared to either GC or KNP groups. With Coke pH cycling; the control group revealed the least µSBS values, followed by KNP and GC conditioning, respectively. All the tested groups are significantly different from each other Considering the erosive pH cycling factor, all the teeth revealed significant decrease in the µSBS values, when exposed to erosive Coke pH cycling. Most failure modes are adhesive, followed by mixed failures. The SEM examination showed a filler‑free zone in the conditioned groups, with the greatest thickness with KNP. Cylindrical shaped resin tags, were observed when dentin is conditioned with KNP, whereas budding configuration is formed with GC conditioner. Smear layer has been completely removed with GC conditioner. Dentin conditioning with KNP revealed partial removal of smear layer with partial obliteration of dentinal tubules, while smear layer remains unaffected in case of control group. In groups stored in AS, there is intimate adaptation between the RMGIC and dentin, whereas the groups subjected to Coke erosive cycles showed variable degrees of separation at the RMGIC/dentin interface. Conclusions: Dentin conditioning before RMGIC application is an essential step to improve bonding ability to dentin. Since Coca cola beverage revealed a deteriorating effect on bonding of RMGICs, evaluation of different acidic foodstuffs, acidic drinks and mouthwashes on the bonding efficiency of different types of glass-ionomer cements is required.

Effect of Er,Cr:YSGG laser associated with fluoride on the control of enamel erosion progression

ObjectiveTo evaluate the effect of Er,Cr:YSGG laser associated or not with acidulated phosphate fluoride (APF) on the control of enamel erosion progression. Design: Enamel slabs (4 mm × 4 mm × 2 mm) from bovine incisors were flattened, polished, and received a tape on their test surfaces, leaving a 4 mm × 1 mm area exposed. Specimens were eroded (10 min in 1% citric acid solution) and randomly assigned into 8 experimental groups (n = 10): Control (no treatment); F (APF gel, 1.23% F, pH 3.6–3.9); Er,Cr:YSGG laser irradiation (P1: 0.25 W, 20 Hz, 2.8 J/cm2, 56 W/cm2); Er,Cr:YSGG laser irradiation (P2: 0.50 W, 20 Hz, 5.7 J/cm2, 1136 W/cm2); Er,Cr:YSGG laser irradiation (P3: 0.75 W, 20 Hz, 8.5 J/cm2, 1704 W/cm2); F + Laser P1; F + Laser P2; F + Laser P3. Specimens were then subjected to erosive cycling (5 min immersion in 0.3% citric acid solution, followed by immersion in artificial saliva for 60 min; 4×/day for 5 days). At the end of cycling, surface loss (SL, in μm) was determined with optical profilometry. Selected specimens were further evaluated by environmental scanning electron microscopy (n = 3). Data were analyzed using Kruskal-Wallis and Tukey tests (α = 0.05). Results: Group F + Laser P2 had the lowest SL value, differing significantly from the control; however, with no significant difference from the other groups. All groups, except F + Laser P2, showed no significant difference in SL when compared with the control. An irregular and rough surface, suggestive of a melting action of laser, was observed on enamel in Laser P2 and F + Laser P2 groups. Conclusions: Association of the Er,Cr:YSGG laser in parameter 2 with fluoride was the only treatment capable of controlling the progression of enamel erosion.

Effect of different methods of vital tooth bleaching on the resistance of enamel to erosion using Energy–Dispersive X-Ray Spectrometry analysis

Objectives: the objective of the current study was to determine the effect of different methods of vital tooth bleaching (power in- office, at-home and over the counter) on the resistance of enamel to erosion. Material and methods: Square enamel sections (4 mm × 4 mm × 3 mm) were obtained from the middle third of the crown of bovine teeth and then embedded in self-curing acrylic resin blocks measuring (2 cm wide and 3 cm high). The samples were divided randomly into 4 groups according to the method of bleaching used. Group 1(control group): where all specimens of the group were placed in artificial saliva at 370 C during the study period. Group 2 (power in- office bleaching): The gel was applied directly on the enamel surface of the specimens where the thickness of the gel was about 1-2 mm, then the LED bleaching device was used. The lamp was located close to enamel surface, then it was turned on for 15 minutes for total application time 45 minutes. Group 3 (Crest 3D White Luxe Supreme FlexFit White strips (over the counter) : the strips were applied to the enamel surface for 30 min twice daily for 14 days according to manufacturer instructions. Group 4 (At-home bleaching): bleaching gel was applied to the enamel surface. Teeth were placed for 6 hours at 370C daily for 8 days. Then, all the samples were subjected to erosive challenge where the bleached samples and the samples of control group were immersed in 1% citric acid solution. Mineral analysis via EDS was carried out before bleaching (base line), then of bleached enamel and finally after erosive cycle. Two representative samples of each group after each step were examined by scanning electron microscope. Results: There was a significant difference regarding the percentage weight of (Ca%), (P%) and (Ca/P%) among the four tested groups. The difference was not significant between group 1 and group 4 after erosion. Conclusions: 1-At-home beaching is considered the least harmful to enamel compared to power in- office and over the counter bleaching materials, and it is more resistant to erosive challenges. 2- Bleaching agents containing calcium decrease the adverse effects of the bleaching procedure. 3-Bleached enamel is less resistant to erosion especially when power in -office or over the counter protocol is used.

Evaluation of the Effect of Beverages on Wear Resistance and Microleakage of Class V Esthetic Restorations

Aim: This study was carried out to evaluate the effect of beverages (orange juice and cola) on the wear resistance and microleakage of: Self cure Glass Ionomer, Flowable bulk fill composite and Packable bulk fill composite. Materials and Methods: Class V cavities were preparered on both the buccal and lingual sides, so a total of ninety cavities were created. Teeth were divided into three main groups according to the material used (30specimens each) (A). the first group was restored with the Riva self-cure glass ionomer (A1), the second group was restored by using flowalble bulk fill SDR, Dentsply (A2), while the third group was restored with packable bulk fill composite resin Filtek p 60 (A3). All Each group was further subdivided into three subgroups (Ten specimens each) (B). The specimens of the first subgroup were immersed in an orange juice for 5 minutes, 3x/day over a period of seven days and kept in artificial saliva between erosive cycles (B1). The specimens of the second subgroup were immersed in an acidic cola drink for 5 minutes, 3x/day over a period of seven days and kept in artificial saliva between erosive cycles (B2). The specimens of the third subgroup were immersed in a saline solution for 5 minutes, 3x/day over a period of seven days and kept in artificial saliva between erosive cycles to be used as control (B3). All specimens were thermocycled (5,00 cycles, 5°C-55°C). Results: Regardless to beverage media, it was found that Flowable bulk-fil composite (A2) group had the highest surface profile mean value followed by Packable bulk-fil composite (A3) group meanwhile Selfcure GI (A1) group had the lowest surface profile mean value. Also, irrespective of the material type, totally it was found that Cola (B2) immersed group recorded the highest surface profile mean values followed by Orange juice (B1) immersed group while Saline (B3) immersed group recorded the lowest surface profile mean value. So, it was found that the flowable composite had the highest surface profile roughness, and also the cola had the highest effect on all materials. Regardless to beverage media, totally it was found that Selfcure GI (A1) had the highest leakage score mean value followed by Packablebulk-fil composite (A3) group meanwhile Flowable bulk-fil composite (A2) group had the lowest leakage score mean. Meanwhile irrespective of the material type, it was found that Orange juice (A1) immersed group had the highest leakage score mean values followed by Cola (A2) immersed group while Saline (A3) immersed group had the lowest leakage score mean value.

Active compounds and derivatives of camellia sinensis responding to erosive attacks on dentin

This research explored the potential of Camellia sinensis-derived teas and active compounds to be used as treatments to prevent dentin wear. Human root dentin slabs were randomly assigned to 5 groups (n = 10) as follows: distilled water (DW, control), epigallocatechin-3-gallate (EGCG), theaflavin gallate derivatives (TF), commercial green tea (GT), and commercial black tea (BT). The samples were submitted to a pellicle formation and an erosive cycling model (5x/day, demineralization using 0.01 M hydrochloric acid/60 s) followed by remineralization (human stimulated saliva/60 min) for three days. The samples were treated for 5 min using the test group solutions between the erosive cycles. Dentin changes were assessed with profilometry analysis and FT-Raman spectroscopy. The data regarding wear were analyzed by ANOVA followed by Tukey's test (p < 0.05). EGCG, TF derivatives, and both regular teas significantly suppressed erosive dentin loss (38-47%, p < 0.05). No obvious changes in the Raman spectra were detected in the specimens; however, the DW group had a minor relationship of 2880/2940 cm-1. The phenolic contents in both green and black tea and the important catechins appear to have protective effects on dentin loss.

The Assessment of the Surface Status Following the Action of Some Acidic Beverages on Indirect Restorative Materials

The study aimed to assess the changes of the surface roughness induced by some acidic beverages on indirect restorative materials by using profilometry. Twenty samples of three composite resins (Ceramage, SR Adoro, Luna-Wing) and three ceramics (IPS In Line, Hera Ceram, Reflex Dimension) immersed in three acidic beverages (Red Bul, wine, Coca Cola), for 5 minutes, three times daily, 14 days. The control samples were immersed in artificial saliva during the study periode. After the end of the erosive cycles and before to determine the surface roughness of the samples in the study groups, all the samples were immersed in artificial saliva for 18 hours. The surface roughness was determined in relation to the baseline surface using profilometer Perthometer_M1 (Mahr Gottingen GmbH, Germany). The immersion of the indirect restorative materials tested in the three acidic beverages lead has resulted to changes in their surface roughness. The most aggressive was wine, followed by Coca Cola, and Red Bull.

An in vitro study on the influence of viscosity and frequency of application of fluoride/tin solutions on the progression of erosion of bovine enamel

ObjectiveTo evaluate the influence of the viscosity and frequency of application of solutions containing fluoride (F) and stannous chloride (SnCl2) on enamel erosion prevention. DesignBovine enamel specimens were randomly distributed into 12 groups (n = 10), according to the following study factors: solution (C: deionized water; F: 500 ppm F−; F + Sn: 500 ppm F− + 800 ppm Sn2+); viscosity (low and high); and frequency of application (once and twice a day). Specimens were submitted to an erosive cycling model, consisting of 5 min immersion in 0.3% citric acid, followed by 60 min exposure to a mineral solution. This procedure was repeated 4×/day, for 5 days. Treatment with the experimental solutions was performed for 2 min, 1×/day or 2×/day. Enamel surface loss (SL) was determined by optical profilometry. Data were analyzed by 3-way ANOVA and Tukey tests (α = 0.05). ResultsThere were significant differences between the levels of the factor solution (p < .001), viscosity (p < .001) and in the interaction between solution and viscosity (p = .01). Regarding solution, the mean SL ± standard deviation for the groups was F + Sn (4.90 ± 1.12) < F (7.89 ± 1.19) < C (14.20 ± 1.69). High viscosity solutions demonstrated less SL than low viscosity; however, only when applied once a day (p < .001). Applying the solutions twice a day yielded lower SL than once a day, but only for the low viscosity solutions (p = .003). ConclusionsUnder the conditions of this short-term in vitro experiment, it could be concluded that increasing the viscosity of the oral rinse solutions reduced enamel loss by erosion; however, this effect was small and only observed when the solutions were applied once a day.

Effect of CPP-ACP on enamel eroded extrinsically: in vitro study

ABSTRACT Objective: The aim of this study was to evaluate the remineralization effect of CPP-ACP on tooth enamel that is eroded extrinsically. Methods: Sixty freshly extracted bovine teeth were stored in a solution of thymol (0.1%), cut into enamel blocks (6x6mm), abraded with silicon carbide sandpaper (600, 800 and 1200 grit) and polished with felt. The specimens were randomly divided into 4 groups (n=15), varying the immersion medium , deionized water or citric acid, and the optional use of CPP-ACP. (G1: deionized water; G2: citric acid; G3: deionized water + CPP-ACP; G4: citric acid + CPP-ACP). The samples were subjected to 4 cycles of erosion every day, comprising 5 minutes immersion in one medium and 2 hours of immersion in artificial saliva, for 5 consecutive days. After each erosive cycle, 20 uL of the MI Paste was applied for 5 minutes on one half of the samples and washed with deionized water. Before and after the erosive cycling, the measurements of Vickers hardness and surface roughness were taken. Results: The results were evaluated through statistical testing. The final hardness and roughness values showed no statistically significant difference between G2 and G4. The paste in G4 did not promote an increase in hardness values nor a decrease in roughness values. Conclusion: It was concluded that CPP-ACP was unable to remineralize enamel subjected to extrinsic erosion, being ineffective in preventing erosion of enamel and in the remineralization of the eroded enamel.

Bonding Performance of Universal Adhesives to Eroded Dentin.

To evaluate the microtensile bond strength (µTBS) and nanoleakage (NL) of several universal adhesives to eroded dentin (ED), using etch-and-rinse (ER) or self-etch (SE) strategies, and to characterize the surface using two pH cycling models to erode dentin (citric acid and a soft drink). Molars were eroded either by soft-drink or citric acid cycling, or were left untreated as control (SD). For each surface, the following adhesives were applied: 1. All-Bond Universal; 2. Ambar Universal; 3. Clearfil Universal; 4. Futurabond U; 5. One Coat 7 Universal; 6. Peak Universal Bond; 7. Prime&Bond Elect; 8. Scotchbond Universal; 9. Tetric n-bond Universal, and 10. Xeno Select. After application of the composite, specimens were sectioned into composite-dentin sticks and tested under tension (0.5 mm/min). Selected sticks from each tooth were used to assess NL. The occlusal dentin surfaces after erosive cycling were examined using SEM. Data were analyzed by three-way ANOVA and Tukey's post-hoc test (a = 0.05). In ED, there was no difference in μTBS and NL between ER and SE strategies (p > 0.61). Most μTBS and NL values obtained for ED were, respectively, lower and higher than those for SD (p < 0.01), being worse for citric acid ED (p < 0.001). Citric-acid-eroded dentin showed more enlarged tubules, with partial loss of peritubular dentin when compared to soft-drink eroded dentin. The different pH cycling models reduced μTBS and increased NL of the composite/eroded-dentin interface; however, in ED, the performance of the universal adhesives did not depend on the adhesive strategy used.

Anti-erosive effect of calcium carbonate suspensions.

BackgroundThis study aimed to investigate the ability of different concentrations of calcium carbonate (CaCO3) suspensions to control enamel surface loss.Material and MethodsSeventy-five enamel slabs were embedded, ground and polished in a pneumatic grinder-polisher machine. Reference areas were created with UPVC tape and the specimens were randomly allocated into five groups (n = 15) for exposure to hydrochloric acid solution to simulate gastric juice (0.01 M, pH 2) for 2 minutes. The samples were then exposed to suspensions containing 0.0001, 0.001, 0.01 or 0.1 mmol/L CaCO3 for 1 minute. Artificial saliva was used as control. The samples were subjected to a total of five erosive cycles followed by treatment with CaCO3 suspension. Surface loss was measured (in µm) using optical profilometry.ResultsOne-way ANOVA (p = 0.009) and Tukey’s test showed a significant reduction in surface loss when compared to the group not exposed to CaCO3 (0.74, +/- 0.23 µm), and the 0.01 mmol/L (0.40; +/- 0.23 µm) and 0.1 mmol/L suspensions (0.37; +/- 0.26 µm).ConclusionsThe lower concentrated suspensions were incapable of significantly reducing enamel surface loss. Rinsing with 0.01 and 0.1 mmol/L calcium carbonate suspensions was revealed as a potentially promising strategy to prevent enamel erosion. Key words:Tooth erosion, gastric acid, calcium carbonate, prevention and control.

In vitro quantitative comparison of erosive potential of infant mouthwashes on glass ionomer cement.

BackgroundThe widespread use of mouthwashes, specially in children, is a concern, since the long-term use may modify the topography of dental materials. However, this process still unclear regarding the wear related to infant mouthwashes on glass ionomer cement. Thus, the purpose of this investigation was evaluate the erosive potential of infant mouthwashes on glass ionomer cement specimens.Material and MethodsForty round-shaped specimens were divided into 4 groups (N=10) and submitted to erosive cycling for 15 days, being exposed 2X/day in the following children’s active agents mouthwash solutions: G1- cetylpyridinium chloride, G2- xylitol and triclosan and G3 - Malva sylvestris and xylitol. Prior to cycling, the specimens were submitted to the surface roughness measurement. After erosive cycling, the specimens were reanalyzed, and calculated the increase of roughness (∆Ra). Additionally, it was adopted distilled water as a negative control (G4). As an extra analysis, the mouthwashes had their pH values measured. The results were submitted to T-test and ANOVA followed by Tukey test at 5%.ResultsIn relation to pH values, G2 presented the most acidic pH value (pH = 6.83) in comparison to other substances. Regarding the comparison of the final roughness values (R) among the groups, it was verified that the mouthwashes showed significant roughness increase in comparison to control group, especially to G3 group (Rf = 1.67 ± 0.14) as well the ΔRa values with statistical difference in comparison to distilled water. Still, with exception of control group outcome, an increase of roughness of each mouthwash was verified after the studied period.ConclusionsActive agents present in infant mouthwashes were capable of roughness increased of glass ionomer cement surface, demonstrating an erosive potential of this material largely used in pediatric dentistry. Key words:Dental erosion, dental cements, mouthwash.

Effect of surface protection on the permeability of eroded dentin.

Context:Eroded dentin might present the opening of dentinal tubules, increasing permeability, and consequently dentinal hypersensitivity.Aims:This study evaluated the permeability of dentin surfaces exposed to different levels of erosion and methods of surface protection.Materials and Methods:Dentine samples (3 mm × 3 mm × 1 mm) were prepared from bovine incisors (n = 90) and divided into three groups according to the method of controlling erosive challenge: Negative control, topical fluoride application, and glass ionomer sealant. Subsequently, they were randomly divided into three subgroups according to the exposure of simulated gastric acid solution (Demineralization – DES) (5% HCl, pH = 2.2), and remineralization (RE); negative control, 9 and 18 cycles DES-RE. The dentin permeability was measured by assessing the hydraulic conductance (μl/min.cmH2O.cm2). Statistical analysis was performed by two-way ANOVA and Tukey's test.Results and Conclusions:Greater permeability was observed after 18 erosive cycles, followed by exposure to 9 cycles and negative control (P < 0.0001). The application of glass ionomer sealant resulted in a major reduction of the hydraulic conductivity, regardless of the erosive challenge. Control groups and topical fluoride application showed similar results. In conclusion, the severity of erosive challenge contributed to the increase of dentin permeability. Besides, the glass ionomer sealant was the only protection agent that promoted significant effects in dentin permeability.

Susceptibility of bovine dental enamel with initial erosion lesion to new erosive challenges.

This in vitro study evaluated the impact of initial erosion on the susceptibility of enamel to further erosive challenge. Thirty bovine enamel blocks were selected by surface hardness and randomized into two groups (n = 15): GC- group composed by enamel blocks without erosion lesion and GT- group composed by enamel blocks with initial erosion lesion. The baseline profile of each block was determined using the profilometer. The initial erosion was produced by immersing the blocks into HCl 0.01 M, pH 2.3 for 30 seconds, under stirring. The erosive cycling consisted of blocks immersion in hydrochloric acid (0.01 M, pH 2.3) for 2 minutes, followed by immersion in artificial saliva for 120 minutes. This procedure was repeated 4 times a day for 5 days, and the blocks were kept in artificial saliva overnight. After erosive cycling, final profile measurement was performed. Profilometry measured the enamel loss by the superposition of initial and final profiles. Data were analyzed by t-test (p<0.05). The result showed no statistically significant difference between groups (GS = 14.60±2.86 and GE = .14.69±2.21 μm). The presence of initial erosion on bovine dental enamel does not enhance its susceptibility to new erosive challenges.

Fluoride Varnishes against Dental Erosion Caused by Soft Drink Combined with Pediatric Liquid Medicine.

The present study evaluated the effect of NaF and CPP-ACP/NaF varnishes to reduce erosion produced by soft drink (SD) combined or not with pediatric liquid medicine. Enamel specimens were pre-treated with fluoride varnish, according to the following groups: NaF varnish (Duraphat®) or CPP-ACP/NaF varnish (MI varnishTM). Two types of erosive cycles were made: by soft drink erosion (SDE) or by pediatric liquid medicine plus soft drink erosion (PLM/SDE). Bovine enamel specimens were randomly assigned in six groups (n=10): G1=NaF + SDE; G2=CPP-ACP/NaF + SDE; G3=Distilled and deionized (DD) water + SDE; G4=NaF + PLM/SDE; G5=CPP-ACP/NaF + PLM/SDE and G6=DD water + PLM/SDE. Before treatments, the sample surface was divided in two areas (unexposed area-UA and exposed area-EA). The specimens were evaluated by 3D non-contact profilometry technique to determinate tooth structure loss (TSL) and surface roughness (Sa). Scanning electron microscopy (SEM) analysis was also performed. After SDE, G2 presented the lowest TSL values compared to G3 (p=0.008). G1 and G2 did not differ between them (p=0.203) and no groups differed among them despite Sa. Regarding TSL and Sa, G4 and G5 differed from G6 (p=0.0001), but not between them (p=1.00). Examining 3D and SEM images, the greatest differences between UA and EA were observed for G3 and G6. CPP-ACP/NaF varnish seems to be a promising treatment to reduce enamel loss from the erosion produced by a soft drink. Both varnishes also showed capacity to reduce TSL and Sa after erosion by soft drink combined to pediatric liquid medicine.