Dentine Wear Research Articles

Effect of combining aminomethacrylate and fluoride against erosive and abrasive challenges on enamel and dentin.

This study evaluated the effect of solutions containing aminomethacrylate copolymer (AA) and sodium fluoride (F; 225ppm F-) or fluoride plus stannous chloride (FSn; 225ppm F-, 800ppm Sn2+) against enamel and dentin erosion/abrasion. Solutions F, FSn, AA, F+AA, FSn+AA, and deionized water as negative control were tested. Bovine enamel and dentin specimens (n=13/solution/substrate) underwent a set of erosion-abrasion cycles (0.3% citric acid [5min, 4×/day], human saliva [1h, 4×/day], brushing [15 s, 2×/day], and treatments [2min, 2×/day]) for each of five days. Initial enamel erosion was evaluated using Knoop microhardness after the first and second acid challenge on day 1, and surface loss with profilometry after day 5. KOH-soluble fluoride was assessed. Data were analyzed with ANOVA/Tukey tests. The combination of fluoride and AA resulted in higher protection against enamel erosion, whereas this was not the case for the combination of AA and FSn. All treatments protected against enamel and dentin loss. The lowest surface loss values were observed with F+AA and FSn+AA. The polymer did not significantly influence the KOH-soluble fluoride formation on enamel/dentin specimens. The aminomethacrylate copolymer effectively enhanced the efficacy of sodium fluoride against initial erosion and improved the control of enamel and dentin wear of F and FSn solutions.

Analysis of dentin wear and biological properties promoted by experimental inoffice desensitizing materials

BackgroundThis study aimed to evaluate dentin wear and biological performance of desensitizing materials.MethodsSeventy bovine root dentin blocks were sectioned. Half of the surface of each specimen was untreated (control) and the other half was immersed in EDTA and treated with the following desensitizing materials: placebo varnish (PLA), fluoride varnish (FLU), sodium fluoride (NaF) varnish + sodium trimetaphosphate (TMP), universal adhesive (SBU), S-PRG varnish (SPRG), biosilicate (BIOS), and amelotin solution (AMTN). After application, the specimens were submitted to an erosive-abrasive challenge and the wear analyzed by optical profilometer. Serial dilutions of extracts obtained from the culture medium containing discs impregnated with those desensitizers were applied on fibroblasts and odontoblasts-like cells cultures. Cytotoxicity and production of total protein (TP) by colorimetric assays were determined after 24 h. Data were statistically analyzed using Kruskal-Wallis, Dunn’s, One-way ANOVA and Tukey tests (p ≤ 0.05).ResultsNo dentin wear was observed only for SBU. The lowest dentin wear was observed for AMTN and TMP. Cell viability was significantly reduced after treatment with undiluted extracts of PLA, FLU, TMP and SBU in fibroblasts and TMP and SBU in odontoblast-like cells. SPRG, BIOS and AMTN were cytocompatible at all dilutions tested. Considering TP results, no statistical difference was observed among the groups and high levels for TP were observed after TMP and FLU treatments.ConclusionsUniversal adhesive system may protect dentin with opened tubules from wear after challenge. Extracts of adhesive and fluoride varnishes presented cytotoxic mainly on fibroblasts. The enamel protein may be a future alternative to treat dentin with opened tubules because it may cause low wear under erosive-abrasive challenge with low cytotoxic effects.

Effect of different brushing parameters on erosive tooth wear in primary bovine enamel and dentin.

This in-vitro study aimed to analyse the effect of brushing and different brushing parameters (kind of toothpaste, kind of toothbrush, brushing force) on erosive tooth wear of primary bovine enamel and dentin. Specimens were prepared from primary bovine enamel or dentin (each group n = 12) and cyclically eroded (6 × 60 s/d, citric acid, pH 2.4) and brushed with children's toothbrushes (2 × 15 s/d) over 5 days. The brushing parameters under investigation were: toothpaste (fluoridated, fluoride-free), toothbrush (manual; rotating-oscillating and sonic, each at two different activation modes) and brushing force (1 N, 2 N). Specimens that were only eroded and not brushed served as controls. Enamel and dentin wear was quantified using widefield confocal microscopy. Statistical analysis was performed using three- and one-way ANOVAs followed by Scheffe's (enamel) or Tamhane's (dentin) post-hoc tests (p < 0.05). Brushing with the fluoridated toothpaste was able to significantly reduce erosive wear in enamel (by 15 to 37%, 6 of 10 groups) and in dentin (by 58 to 72%, all groups), while brushing with the fluoride-free toothpaste was not different from the controls. Considering the kind of toothpaste and brushing force, slight differences between the toothbrushes were observed in enamel, but not in dentin. Within the same toothbrush and activation mode, almost no differences between 1 and 2 N brushing force were detected. In conclusion, erosive tooth wear on primary bovine dental hard tissue mainly depends on the kind of toothpaste, rather than on the kind of toothbrush and the brushing force.

Low-fluoride gels supplemented with nano-sized sodium trimetaphosphate reduce dentin erosive wear in vitro

ObjectiveThe study assessed the effect of low-fluoride gels supplemented with micrometric or nano-sized sodium trimetaphosphate (TMP) on dentin erosive wear in vitro. DesignBovine dentin blocks (n = 154) were selected by surface microhardness and randomly allocated into seven groups (n = 22/group), according to the gels: Placebo; 4500 ppm F (4500F); 9000 ppm F (9000F); 5% TMP microparticulate plus 4500F (5TMPm+4500F); 2.5% TMP nanoparticulate plus 4500 F (2.5TMPn+4500F); 5% TMP nanoparticulate plus 4500F (5TMPn+4500F); and 12,300 ppm F acid gel (APF). All blocks were treated only once for 60 s and cyclically eroded (ERO, citric acid, 4 × 90 s/day) or eroded and brushed (4 × 15 s/day, five strokes/s, ERO+ABR) over five days (each subgroup n = 11). Dentin wear and integrated hardness loss in depth (ΔKHN) were determined, and the data were submitted to two-way ANOVA, followed by Tukey’s test, and Spearman’s correlation (p < 0.05). ResultsFor ERO, all gels containing 4500F supplemented with TMP significantly reduced dentin wear compared with their counterpart without TMP, reaching values similar to 9000F. For ERO+ABR, 5TMPn+ 4500F gel led to significantly lower wear than all its counterparts, reaching values similar to 9000F and APF. As for ΔKHN, all gels containing TMP promoted superior protective effects compared with 4500F, reaching values similar to 9000F and APF under both challenges. A positive correlation between dentin wear and mineral content in depth was verified. ConclusionsGels containing 4500F supplemented with TMP significantly reduced dentin erosive wear compared with pure 4500F, with additional benefit from the use of nanoparticles.

Root canal dentin wear during final irrigation in endodontic retreatment with passive ultrasonic irrigation and easy clean instruments.

Complementary procedures have been proposed to improve the endodontic retreatments. The aim of this study was to evaluate, by microcomputed tomography (micro-CT), the dentin wear caused by passive ultrasonic irrigation (PUI) and easy clean (EC) instruments, when used for the final removal of filling material during endodontic retreatment. Thirty-six mesial roots of the lower first molars were divided into four groups (n = 9), according to the final irrigation and sealer: PUI/AH Plus, EC/AH Plus, PUI/Total Fill (TF), and EC/TF. Canal volume was evaluated, both before and after the final irrigation, by micro-CT analysis. The Kruskal-Wallis test was used to compare the volumes among groups and the paired Wilcoxon test was used to compare the volume values before and after the final irrigation within each group. Both complementary cleaning procedures promoted dentin wear that was observed only when the volume was analyzed for each third of the root canal. In the apical third, both instruments showed significant wear, where the use of the EC instrument resulted in greater wear than the PUI, in teeth filled with both AH Plus and TF BC Sealers (P < 0.05). Both complementary cleaning procedures promoted dentin wear and must be used cautiously.

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.

Preventive effect of children's toothpastes on erosive tooth wear of primary enamel and dentin

Preventive effect of children's toothpastes on erosive tooth wear of primary enamel and dentin

The potential of galactomannan from Caesalpinia ferrea on erosive dentin wear reduction in vitro.

Gels containing juca seed galactomannan (JSG) were evaluated for their potential to prevent the progression of dentin erosive wear in an in vitro study with four experimental groups (n = 9). The treatments included distilled water (DW), 0.05% stannous fluoride (121 ppm F), and 0.5% or 1% JSG. The specimens underwent a cycle (3 times/day) consisting of immersion in 1% citric acid (5 minutes), treatment (5 minutes), and artificial saliva exposure (2 hours/overnight) for 5 days. Surface changes were assessed using mechanical profilometry (wear), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The data were analyzed using ANOVA followed by Tukey's post-test (p < 0.05). The negative control group exhibited the highest wear (6.0 µm ± 3.5), significantly differing from the group treated with 0.05% stannous fluoride gel (p = 0.007), which showed less dentin loss. The groups treated with 0.5% and 1% JSG showed results similar to the negative control (p = 0.661; p = 0.212, respectively) and the stannous fluoride group (p = 0.103; p = 0.379, respectively). In the SEM images, the specimen treated with stannous fluoride showed obliterated tubules, while the JSG gels formed crystals on the dentin surface, as confirmed by the presence of oxygen and calcium in the EDS analysis. Although the JSG gels showed similar results to the stannous fluoride, did not exhibit superior efficacy at the tested concentrations.

Preventive effect of Cranberry gel on dentin submitted to erosion

Objectives: Considering that Cranberry’s components might inhibit dentin metalloproteinases exposed to erosive agents, the aim of this study was to evaluate in situ effect of a Cranberry gel application on dentin before an erosive challenge.&#x0D; Methods: This crossover double-blinded study was performed in 2 phases of 5 days each, with 10 healthy volunteers who wore 2 palatal devices (1 for each phase) with 4 dentin specimens (2 specimens for each group). The groups under study were; First Phase: G1 - Erosive challenge (Coca-cola®) over dentin without any previous treatment (1st negative control group); G2 - Erosive challenge over dentin previously treated with Cranberry gel (test group); and Second Phase: G3 - Erosive challenge over dentin previously treated with a gel without any active principle (2ndnegative control group); G4 - Erosive challenge over dentin previously treated with 0.12% Chlorhexidine gel (positive control group). Each device was immersed into the acid beverage, 3 times daily for 5 minutes during 5 days. Profilometry (µm) was used to quantify the dentin wear. Data were analyzed by Repeated Measures Analysis of Variance followed by Fisher's test (p&lt;0.05).&#x0D; Results: Data (G1: 4.98 ± 1.36a; G2: 3.29 ± 1.16b; G3: 4.38 ± 1.19a; G4: 3.32 ± 1.55b) showed no statistical difference between G1 and G3. There was also no difference between G2 and G4. However, G2 and G4 presented lower wear when compared to G1 and G3, and this difference was statistically significant.&#x0D; Conclusion: The results of this study suggest a significant efficacy of Cranberry gel in preventing wear of dentin subjected to dental erosion.&#x0D; &#x0D; Financial Support: FAPESP (Process 2012/16295-7) and MaRS IPoP Fund&#x0D; &#x0D; Keywords: Collagen, Dentin, Erosion, Preventive dentistry and Wear

Different vehicles containing CaneCPI-5 reduce erosive dentin wear in situ.

This study evaluated the protective capacity of a sugarcane-derived cystatin (CaneCPI-5) in different vehicles (1-solution and 2-chitosan gel) against erosive dentin wear in situ. In part-1, 15 volunteers participated in a crossover protocol (solutions): Water; Elmex™ and CaneCPI-5. The volunteers wore an appliance with 4 dentin samples for 5days. These samples were treated with a drop of the solutions for 1min (4X/d), then the acquired pellicle (AP) was formed and the samples were subjected to erosive challenges (EROSION: citric acid, for 90s, 4X/day). 2X/day, half of the samples were also abraded for 15s (ABRASION). In part-2, 16 volunteers participated in a crossover protocol (gel): No gel, Chitosan gel, Chitosan gel + NaF and Chitosan gel + CaneCPI-5. The volunteers also wore an appliance. The samples were treated once/day with the gel or not for 4min, then the AP was formed and the samples were subjected to erosive and abrasive challenges, as reported in part-1. Dentin wear was measured by profilometry. Data were analyzed by two-way RM-ANOVA and Sidak's tests (p < 0.05). Part-1: Elmex™ and CaneCPI-5 significantly reduced dentin loss in comparison with Water for the EROSION/ABRASION conditions (p < 0.05). Part-2, all the treated groups significantly reduced the dentin loss in comparison to the No gel. The greatest reduction was found for the gel + CaneCPI-5 group for the EROSION/ABRASION (p < 0.05). The solution and chitosan gel containing CaneCPI-5 protected against erosive dentin wear in situ. These different vehicles are probably sufficient for protecting people with high risk of developing erosive dentin wear.

In vitro study on the preventive effect of children’s toothpastes on erosive tooth wear of primary bovine enamel and dentin

This in vitro study aimed to analyse the effect of various children’s toothpastes on erosive tooth wear of primary bovine enamel and dentin. Enamel and dentin specimens (n = 12) were cyclically eroded (6 × 60 s/d, citric acid, pH 2.4) and brushed (2 × 15 s/d, 2 N) over 5 days. Nine fluoride toothpastes (500 to 1450 ppm) and eight toothpastes containing no fluoride or other active ingredients (hydroxyapatite and/or xylitol) were tested. Unbrushed specimens served as control. Tissue loss was quantified using widefield confocal microscopy and statistically analysed using two-way and one-way ANOVAs followed by Scheffe’s (enamel) or Tamhane’s (dentin) post-hoc tests (p < 0.05). Only one fluoride toothpaste (1400 ppm) was able to reduce erosive wear of enamel significantly by 15% compared to the control (padj. = 0.002). All fluoridated toothpastes reduced dentin surface loss significantly by 32 to 69% compared to the control (padj. ≤ 0.001), while fluoride-free toothpastes were unable to reduce dentin loss significantly (padj. ≥ 0.971). Most fluoridated toothpastes caused less erosive wear compared to fluoride-free toothpastes. Children toothpastes containing fluoride were more effective in reducing erosive wear compared to toothpastes containing no fluoride or other active ingredients.

Intraradicular Dentinal Changes Following Fiber Postremoval: Micro-computed Tomography Analysis

Abstract Context: Excessive dentine wear during postremoval can occur due to the adhesion between the cement and the post. Aim: The aim is to evaluate dentine wear and microcrack occurrence following the removal of intraradicular fiberglass posts that were previously cemented with two types of resin cement. Methods: Distal roots (n = 38) of lower molars were instrumented, filled, prepared for intraradicular postinstallation, and divided into two groups according to the cement used for the posts: RelyX ARC or RelyX U200. The posts were removed through abrasion using ultrasonic diamond tips, after which the degrees of dentine wear (volume/mm3) and microcrack formation were assessed using microcomputed tomographic imaging. Statistical Analysis Used: The Mann–Whitney U (P ≤ 0.05) and Chi-squared tests (P ≤ 0.05) were used. Results: After the removal of the posts, no statistically significant difference in root canal volume or microcrack occurrence was observed between the groups (P &gt; 0.05). The procedure produced significant dentine wear regardless of the type of cement used (P &lt; 0.05). Conclusions: The removal of fiberglass posts caused extensive dentine wear but did not influence microcrack occurrence. The type of resin cement used did not affect the dentine loss or microcrack appearance that resulted from fiberglass postremoval.

Wear effects between polymethyl methacrylate occlusal splints and opposing dentin surfaces during bruxism mimicking events

ObjectivesTo compare the surface wear rate between polymethyl methacrylate (PMMA)-based occlusal splints and opposing dentin-exposed teeth in bruxism simulating models.Materials and methodsPMMA-based occlusal splints and extracted premolars were tested on a chewing stimulator at 30,000 or 60,000 cycles. Dentin wear was measured under a stereomicroscope and PMMA wear was determined with an optical profilometer. In addition, wear surface topography was assessed and quantified by scanning electron microscopy (SEM).ResultsWear rate of PMMA was significantly greater (11 times) than that of dentin specimens at 60,000 cycles, though these findings were not observed at 30,000 cycles. When comparing wear rates within each group at different duration cycles, PMMA surfaces exhibited an average wear rate 1.4 times higher with high duration cycles, while dentin surfaces displayed a marginal decrease in wear. In SEM micrographs, PMMA surfaces displayed more wear abrasion lines with higher duration cycles. However, dentin surfaces did not exhibit major differences between low and high duration cycles.ConclusionWear rate on PMMA-based occlusal splints remarkably increases upon high chewing cycles mimicking bruxism comparing with the rate on dentin. Hence, it is reasonable for bruxing patients to wear single-arch PMMA-based occlusal splints to protect opposing dentin-exposed teeth.

The roles of theaflavins in reducing dentin erosion

This study aimed to evaluate the effect of theaflavins [TFs] on the process of dentin erosion and investigation the potential mechanism. For erosion kinetics of the dentin, 7 experimental groups (n = 5) treated with 10% ethanol [EtOH] (negative control) are erosion for 1, 2, 3, 4, 5, 6, and 7 d erosion cycles (4 cycles/d). For the effect of TFs on dentin erosion, 6 experimental groups (n = 5) were treated with 1% epigallocatechin gallate [EGCG], 1% chlorhexidine [CHX], 1%, 2%, 4%, and 8% TFs for the 30 s and then subjected to erosion cycles (4 cycles/d for 7 d). The erosive dentin wear (μm) and surface morphology were evaluated and compared by laser scanning confocal microscope and scanning electron microscopy. The matrix metalloproteinase inhibition effects of TFs were investigated using in situ zymography and molecular docking. TFs-treated collagen was investigated by ultimate microtensile strength, Fourier-transform infrared spectroscopy, and molecular docking. Data were analyzed by ANOVA, Tukey’s test (P < 0.05). The TFs-treated groups (7.56 ± 0.39, 5.29 ± 0.61, 3.28 ± 0.33, and 2.62 ± 0.99 μm for 1%, 2%, 4%, and 8% TFs) had significantly lower erosive dentin wear than the negative control group (11.23 ± 0.82 μm), and the effect was concentration-dependent at low concentrations (P < 0.05). TFs inhibit matrix metalloproteinase [MMP]. Moreover, TFs crosslink dentin collagen and cause hydrophilic changes in dentin collagen. TFs preserve organic matrix within the demineralized dentin by inhibiting MMP activity and simultaneously improving collagen’s resistance to enzymes, both of which contribute to preventing or slowing down the progression of dentin erosion.

Anti-erosion effect of an experimental varnish on eroded dentin.

This in vitro study evaluated the effect of an experimental varnish containing 20% nano-hydroxyapatite (nHAP) associated with 5% stannous chloride (SnCl2) against erosive-abrasive wear on bovine dentin. Samples of bovine cervical dentin were pre-eroded (0.3% citric acid, pH 2.6 for 10 minutes) and randomized into 4 groups (n=10): Control group - experimental varnish without active ingredient (CG); experimental varnish containing 20% nHAP (nHG); experimental varnish containing 5% SnCl2 (24.800 ppm Sn2+) (SnG); experimental varnish containing 20% nHAP associated with 5% SnCl2 (18.300 ppm Sn2+) (nHSnG). After applying the materials, the erosive-abrasive challenges were performed for five days. Erosive dentin loss and analysis of the pattern of dentinal obliteration were performed by 3D confocal laser microscopy. A one-way ANOVA/Bonferroni test was performed to analyze the data (α=0.05). The SnG and nHSnG experimental groups presented more effectiveness in preventing erosive wear when compared to the other groups (p<0.05). There was no statistically significant difference between the SnG and nHSnG groups (p = 0.731) in tooth structure dentin loss. Regarding the amount of open dentinal tubules, the highest amount of obstructed dentinal tubules was demonstrated in SnG and nHSnG (p < 0.05) when compared to the others. Between SnG and nHSnG there was no significant difference (p = 0.952) in the amount of closed dentinal tubules in the dentin. Experimental varnishes containing 5% SnCl2 associated or not with 20% nHAP showed to be a promising strategy in preventing erosive-abrasive wear of dentin. In addition, nHSnG was able to obliterate dentinal tubules.

Effect of Whitening Toothpastes with Different Active Agents on the Abrasive Wear of Dentin Following Tooth Brushing Simulation.

The aim of this research was to evaluate the abrasive dentin wear that can be induced by three commercial whitening toothpastes following a tooth-brushing simulation (TBS) corresponding to a three-month period. Sixty human canines were selected, and the roots were separated from the crowns. Then the roots were randomly divided into six groups (n = 10) and were submitted to TBS using the following slurries: Group 1-deionized water (RDA = 5); Group 2-ISO dentifrice slurry (RDA = 100); Group 3-a regular toothpaste (RDA = 70); Group 4-a charcoal-containing whitening toothpaste; Group 5-a whitening toothpaste containing blue covasorb and hydrated silica; and Group 6-a whitening toothpaste containing microsilica. Following TBS, surface loss and surface roughness changes were evaluated using confocal microscopy. Additionally, surface morphology and mineral content changes were observed using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The deionized water group presented the lowest surface loss (p < 0.05), while the charcoal-containing toothpaste presented the highest surface loss, followed by ISO dentifrice slurry (p < 0.001). Blue-covasorb-containing and regular toothpastes did not present statistically significant differences (p = 0.245), and neither didmicrosilica-containing toothpaste or ISO dentifrice slurry (p = 0.112). The surface height parameters and surface morphology changes of the experimental groups followed the surface loss patterns, while no differences were detected in mineral content after TBS.Although the charcoal-containing toothpaste exhibited the highest abrasive wear to dentin, according to ISO 11609, all the tested toothpastes exhibited appropriate abrasive behavior towards dentin.

Impact of bariatric surgery on oral health: a systematic review and meta-analysis.

To evaluate the impact of bariatric surgery (BS) on the oral health status of obese individuals. The search was performed on the Cochrane Library, Embase, Latin American and Caribbean Literature on Health Sciences (LILACS), LIVIVO, PubMed/Medline, Scopus, and Web of Science databases. Grey literature was also consulted through Google Scholar, OpenGrey, ProQuest, and MedRxiv. The risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal tool. Pre- and post-surgical moments were compared through random effects meta-analysis. The GRADE (Grading of Recommendations, Assessment, Development and Evaluations) assessment tool was used to judge the certainty of evidence. After searching the databases, 908 references were retrieved, with 30 articles selected for synthesis. When comparing the pre- and postoperative moments, there was no difference in the index of decayed, missing, or filled teeth. Furthermore, salivary flow and probing depth presented a slight increase. Post-surgery patients showed an increase (%) in tooth wear at the dentin level [MD = -6.23; IC95% = -8.45--4.01; I2 = 0%]. Patients undergoing BS show no difference when considering the rate of caries or missing teeth and little to no effect was observed on salivary flow rates and periodontal probing depth. On the other hand, greater attention should be given to dentin wear in post-surgical patients of BS. Patients undergoing BS should receive careful monitoring regarding oral health by doctors, dentists, and the entire multidisciplinary team involved before and after the surgical procedure.

Abrasive Enamel and Dentin Wear Resulting from Brushing with Toothpastes with Highly Discrepant Relative Enamel Abrasivity (REA) and Relative Dentin Abrasivity (RDA) Values.

To investigate the absolute wear caused by toothpastes with highly discrepant REA (Relative Enamel Abrasivity) and RDA (Relative Dentin Abrasivity) values on both enamel and dentin: Candida Peppermint (CP; REA: 1; RDA: 42), Colgate Total Original (CTO; REA: 4; RDA: 100), Signal White System (SWS; REA: 8; RDA: 143), and Candida White Diamond (CWD; REA 244; RDA: 12). Eighty (80) bovine enamel samples and 80 dentin samples were divided into four groups each (n = 20) and investigated after a 6-h brushing procedure (21,600 cycles, 60 cycles/min, load of 2.5 N) with the four toothpastes. The abrasive enamel and dentin wear were registered using a contact profilometer. The median and interquartile range (IQR) of the abrasive enamel and dentin wear were calculated for each group. Pairwise comparisons were conducted using the Wilcoxon signed-rank exact test, and the p-value was adjusted according to Holm (statistical significance set at 0.05). CWD led to the highest abrasive enamel wear (9.86 μm [5.77]). CTO caused the highest abrasive dentin wear (166.70 μm [69.90]), being statistically significantly higher than the wear for CP (54.20 μm [24.00]) and CWD (17.00 μm [7.80]) (p = 0.00001). The abrasive dentin wear for CWD was statistically significantly lower in comparison to all other groups (p = 0.00001). Toothpastes with highly discrepant REA and RDA values presented statistically significantly different absolute wear on enamel and dentin. REA and RDA values should both be declared for every toothpaste.

The in vitro Effect of Dentifrices With Activated Charcoal on Eroded Teeth

The objective of this research was to compare the abrasive potential of dentifrices containing activated charcoal with those of a conventional dentifrice on the development of erosive tooth wear (ETW) in vitro. Enamel and dentin samples were divided into toothpastes (n=12): group (G)1-Colgate Triple Action (1450 ppm F) (positive control); G2-Colgate Natural Extracts (1450 ppm F); G3-Colgate Luminous White Activated Carbon (1450 ppm F); G4-Oral-B Whitening Therapy Charcoal (1100 ppm F); G5-Oral-B 3D White Mineral Clean (1100 ppm F); G6-Curaprox Black Is White (950 ppm F); and G7-erosion only (no abrasion, negative control). All samples were submitted to erosive pH cycles and G1 to G6 to abrasive challenges (15 seconds) using toothpastes' slurries plus 45 seconds of treatment for 7 days. The final profile was overlaid to the baseline one for the ETW calculation (µm). The data were subjected to analysis of variance/Tukey or Kruskal-Wallis/Dunn tests (P < .05). Oral-B 3D White (13.0 ± 1.0, 9.37 [1.36] μm), Oral-B Whitening Therapy (15.1 ± 1.2, 8.58 [1.71] μm), and Colgate Luminous White (13.6 ± 1.0, 7.46 [0.94] μm) toothpastes promoted the greatest enamel and dentin wear. On the other hand, Colgate Triple Action (12.2 ± 1.2, 5.30 [1.26] μm), Colgate Natural Extracts (10.8 ± 1.1, 4.16 [1.11] μm), and Curaprox Black Is White (11.5 ± 1.5, 4.06 [0.92] μm) toothpastes promoted lower wear values, similar to erosion only (4.16 [0.94] μm) in the case of dentin but not enamel (7.1 ± 0.8 μm). Toothpastes containing charcoal combined with pyrophosphate may have a high abrasive effect on eroded tooth surfaces. Many patients influenced by digital marketing use toothpastes containing activated charcoal with the aim of bleaching their teeth. However, care should be taken when using these products, as they may have a high abrasive effect.

The early wear susceptibility of cementum, enamel and dentine in vitro

ObjectivesTo assess the differential early wear susceptibility of cementum, enamel and dentine at a micron level. MethodsWhole human molar buccal surfaces incorporating natural enamel and cementum (n = 20) confirmed by imaging (digital microscopy: Keyence, VHX-7000 Milton Keynes, UK), were mounted, scanned (profilometry: XYRIS 4000, Taicaan, Southampton, UK), and allocated to receive erosion (citric acid, pH 2.7, 30 min (n = 10)) or erosion/abrasion challenges (3 cycles of (citric acid, pH 2.7, 10 min, 60 300 g linear abrasion strokes), n=10). Samples were polished and the experiment repeated on polished enamel, and polished coronal and radicular dentine within the same tooth. Profilometric wear data were obtained using superimposition: GeoMagic (3Dsystems, Darmstadt, Germany) and subtraction: MountainsMap (DigitalSurf, Besancon, France). Data were normal. A general linear model was used to assess differences between groups and substrates. ResultsThe mean step height (SD) for natural enamel was 8.82 μm (2.53) for erosion and 11.48 μm (2.95) for erosion/abrasion. For natural cementum, the mean step height was 6.00 μm (2.29) for erosion and 4.67 μm (1.58) for erosion/abrasion. Dentine step heights ranged from 7.20 μm (1.53) for erosion and 9.79 μm (1.01) for erosion/abrasion with no statistical differences in dentine wear. Natural cementum surfaces had the lowest wear (p<0.001). Dentine had significantly less wear than natural enamel (p<0.02). ConclusionsCementum surfaces demonstrated the most wear resistance, followed by dentine under erosion dominant conditions in this in vitro study. Further in-vivo investigations are needed to confirm the intraoral stability of cementum. Clinical SignificanceCementum may be the least susceptible of dental substrates to wear and dentine does not wear at a faster rate than enamel under erosive conditions. This adds to our knowledge on the development of non-carious cervical lesions and questions whether wear rates will accelerate once dentine is exposed.