Dentin erosive wear is reduced by fluoride varnishes containing nanosized sodium trimetaphosphate in vitro.

This study evaluated the effect of fluoride varnishes containing micrometric or nanosized sodium trimetaphosphate (TMP) on dentin erosive wear in vitro. Bovine root dentin blocks were selected by surface hardness and randomly divided into five experimental groups/varnishes (n = 20/group): placebo, 5% sodium fluoride (NaF); 5% NaF+5% micrometric TMP; 5% NaF+2.5% nanosized TMP; and 5% NaF+5% nanosized TMP. Half of the surface of all blocks received a single application of the assigned varnish, with subsequent immersion in artificial saliva for 6 h. Varnishes were then removed and the blocks were immersed in citric acid (90 s, 4×/day, 5 days). After each erosive cycle, ten blocks of each group were immersed in a placebo dentifrice for 15 s (ERO), while the other ten blocks were subjected to abrasion by brushing (ERO+ABR). Dentin erosive wear was assessed by profilometry. Data were submitted to 2-way ANOVA and to the Holm-Sidak test (p<0.05). Dentin erosive wear was significantly higher for ERO+ABR than for ERO for all varnishes. TMP-containing varnishes promoted superior effects against dentin erosive wear compared with 5% NaF alone; and 5% nanosized TMP led to the lowest wear among all varnishes. In conclusion, the addition of TMP to conventional fluoride varnish (i.e., varnish containing only NaF) enhanced its protective effects against bovine root dentin erosion and erosion+abrasion. Additionally, the use of 5% nanosized TMP led to superior effects in comparison to 5% micrometric TMP, both for erosion and erosion+abrasion in vitro.

Stain removal, abrasion and anticaries properties of a novel low abrasion dentifrice containing micro-fibrillated cellulose: in vitro assessments.

OBJECTIVES: This laboratory study assessed the performance of a novel fluoride dentifrice containing micro-fibrillated cellulose (MFC) and entrapped silica. METHODS: Removal of extrinsic stains was assessed using the pellicle cleaning ratio (PCR) method, and radioactive dentin abrasivity (RDA) was measured, to calculate a cleaning efficiency index (CEI). Fluoride efficacy was evaluated using widely used remineralization and fluoride uptake methods. The test product (Protegera™) was compared to common dentifrices (Crest - Cavity Protection™ and ProHealth™, Sensodyne Pronamel™, Arm & Hammer™ Advanced Whitening, Crest ProHealth™, and Colgate Optic White™). RESULTS: The PCR for the MFC dentifrice (141) was comparable to three known marketed stain-removing dentifrices (Arm & Hammer™ Advanced Whitening, Crest ProHealth™, and Colgate Optic White™) but it had a significantly lower RDA (88 ± 6) than 5 other products. This gave it the highest CEI of the tested products (2.0). In a 10-day pH cycling study, the fluoride efficacy of the MFC product was comparable to Sensodyne Pronamel and Crest Cavity Protection. The MFC dentifrice was superior for promoting fluoride uptake into incipient enamel lesions compared to the USP reference dentifrice. CONCLUSION: The MFC dentifrice has low abrasion, but despite this, it is highly effective in removing stained pellicle. It also is an efficacious fluoride source when compared to relevant commercially available fluoride dentifrices with high dentin abrasivity. CLINICAL SIGNIFICANCE: The addition of micro-fibrillated cellulose to a fluoride dentifrice gives a low abrasive product that can effectively remove external stains, and serve as an effective fluoride source. This combination of benefits seems well suited to enamel protection and caries prevention.

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.

Tooth surface loss: causes, management, and prevention.

OBJECTIVES: Tooth wear, also referred to as tooth surface loss, occurs due to causes other than caries. This involves the loss of hard tissues, namely enamel, dentin, and/or cementum. Types of tooth wear/tooth surface loss are abrasion, abfraction, attrition, and erosion. These multifactorial conditions can be caused by factors such as lifestyle, diet, or even habits, and may not be symptomatic. The focus of this article is to provide clinicians with detailed examples and explanations of the causes of tooth loss to aid in early diagnosis. Through early identification, the preventive measures outlined can be implemented to avoid excessive tooth wear. The provision of a treatment flowchart and general treatment recommendations aims to help clinicians determine when to restore these lesions and the most appropriate treatment measures for the four types of wear. METHOD AND MATERIALS: The PubMed (MEDLINE) search engine was used to gather information on teeth restricted to a 5-year period (26 August 2018 to 25 July 2022). Only English-language studies and reviews with the best balance of sensitivity and specificity were considered. A Boolean search of the PubMed dataset was implemented to combine a range of keywords: ("tooth wear" OR tooth attrition OR tooth erosion OR tooth abrasion OR tooth abfraction). Additional articles were selected through Google Scholar. RESULTS: By this process, many articles and studies were obtained, and the 48 most relevant published studies were chosen and used in the current review. CONCLUSION: Tooth wear affects an increasing number of individuals and can have detrimental effects physically, mentally, and emotionally. It is important to stress early diagnosis and management of tooth wear through monitoring, prevention, and treatment where indicated.

Toothpaste containing TiF4 and chitosan against erosive tooth wear in situ.

OBJECTIVE: This study compared the protective effect of an experimental TiF4/Chitosan toothpaste with a commercial toothpaste on the prevention of erosive tooth wear (ETW) in situ. METHODS: Fifteen subjects took part in this crossover and double-blind study, in which they wore a palatal appliance containing 4 bovine enamel and 4 dentin in 3 phases (5 days each). Half of the samples were subjected to erosive challenges (90 s in 0.1 % citric acid, pH 2.5, 4 times/day), and the other half to erosive plus abrasive challenges (15 s plus 45 s of contact, 2 times/day). The phases corresponded to the application of the different toothpastes: 1) TiF4 (1400 ppm F-) plus Chitosan, 2) Elmex®, Erosion Protection (1400 ppm F-, Chitosan), and 3) Placebo (negative control). Tooth wear was measured using contact profilometry (µm) and submitted to two-way RM ANOVA/Tukey test (p < 0.05). RESULTS: No significant differences were detected between the experimental and commercial toothpastes, regardless of the challenge on both tissues. Both significantly reduce ETW compared to negative control (p < 0.0006). Tooth wear was increased by brushing only on eroded enamel (p < 0.01), but not on dentin (p = 0.6085). TiF4/Chitosan [erosion 2.98 ± 1.12 µm vs. erosion and abrasion 3.12 ± 1.33 µm] and Elmex® toothpastes [erosion 2.35 ± 0.93 µm vs. erosion and abrasion 2.98 ± 1.0 µm] minimized the impact of brushing compared to placebo on enamel [erosion 4.62 ± 1.48 µm vs. erosion and abrasion 5.15 ± 1.50 µm]. CONCLUSIONS: TiF4 plus chitosan toothpastes showed to be effective in minimizing the ETW as the commercial toothpaste is in situ. CLINICAL RELEVANCE: The experimental toothpaste has similar effect against ETW compared to the commercial toothpaste. Considering the increased ETW prevalence worldwide, this result supports clinical trials and a possible application of this experimental anti-erosive toothpaste in the future.

Characteristics of tin-containing fluoride toothpastes related to erosive tooth wear protection.

OBJECTIVES: To assess the effect of different tin-containing toothpastes on the control of erosive tooth wear in enamel and dentin. METHODS: Enamel and dentin slabs were randomly distributed into 7 experimental groups (n = 10/substrate): C-: negative control (Artificial saliva); AmF (regular fluoridated toothpaste without tin); Sn-1 (SnF2/NaF); Sn-2 (SnF2/NaF/SnCl2); Sn-3 (SnCl2/NaF); Sn-4 (SnF2/SnCl2); Sn-5 (SnCl2/AmF/NaF/chitosan). Specimens were submitted to 5-day erosion-abrasion cycling. Surface loss (SL) was determined with an optical profilometer. Tin deposition on the tooth surfaces and some characteristics of the toothpastes (pH, potentially available F-, %weight of solid particles, and RDA) were also assessed. Data were statistically analyzed (α = 0.05). RESULTS: For enamel, the Sn-2 presented the lowest SL, not differing significantly from AmF, C+, and Sn-3. The SL of these groups was significantly lower than the C-, except for Sn-3. Sn-1 and Sn-4 were also not significantly different from C-. For dentin, C- significantly showed the highest SL values, whilst, Sn-1 presented the lowest SL, not differing significantly from AmF, Sn-2, C+, and Sn-3. There was a significant positive association between enamel SL and the pH and tin deposition. Dentin SL was significantly negatively associated with the %weight of solid particles and RDA. CONCLUSIONS: Most of the tin-toothpastes were able to exhibit some protection against ETW. In this process, the toothpastes characteristics play a role, as lower enamel SL was significantly associated with lower pH values and tin deposition; and lower dentin SL was associated with higher %weight of solid particles and RDA of the toothpastes. CLINICAL SIGNIFICANCE: Tin-containing toothpastes can be used for erosive tooth wear protection, but our study showed that their effect depends on the pH, amount of tin deposition, % weight of solid particles and RDA of the toohpastes.

Impact of toothbrush head configuration and dentifrice abrasivity on non-carious cervical lesions in-vitro.

OBJECTIVE: To investigate the effect of toothbrush head configuration and dentifrice slurry abrasivity on the development of simulated non-carious cervical lesions (NCCLs) in vitro. METHODS: Extracted premolars were randomly allocated into 15 groups (n = 16) generated by the association between toothbrush head configuration (flat-trimmed, rippled, cross-angled/multilevel/rubbers added, cross-angled/multilevel/flex head, feathered) and dentifrice slurry abrasivity (low/medium/high). Teeth were mounted on acrylic blocks and had their roots partially covered with acrylic resin, leaving 2-mm root surfaces exposed. Toothbrushing was performed for 35,000 and 65,000 double-strokes. Specimens were analyzed using non-contact profilometry for dental volume loss (mm3) and lesion morphology. Data was analyzed using ANOVA with pairwise comparisons and Kruskal-Wallis tests. RESULTS: The two-way interaction between toothbrush head configuration and slurry abrasivity was significant (p = 0.02). At 35,000 strokes, the flat-trimmed and cross-angled/multilevel/rubbers added toothbrushes caused the highest loss, when associated to the high-abrasive slurry (p<0.05); whereas cross-angled/multilevel/flex head showed the least loss, when associated to the low-abrasive (p<0.05). At 65,000, more dental loss was observed for all toothbrushes when associated to the high-abrasive slurry, with flat-trimmed causing the highest loss (p < 0.05). Lower dental loss rates were observed for cross-angled/multilevel/flex head associated to the low-abrasive slurry when compared to the other toothbrushes (p < 0.05), except to feathered (p = 0.14) and rippled (p = 0.08). Flat lesions (mean internal angle ± standard-deviation: 146.2°± 16.8) were mainly associated with low-abrasive slurry, while wedge-shaped lesions (85.8°± 18.8) were more frequent with medium- and high-abrasive slurries. CONCLUSION: The development, progression and morphology of simulated NCCLs were modulated by both toothbrush head configuration and dentifrice abrasivity. CLINICAL SIGNIFICANCE: Dental professionals should consider both the type of toothbrush and dentifrice abrasivity in the management plan of patients at risk of developing NCCLs.

Description of a new laboratory evaluation method of interdental brush abrasion as a clinical hazard.

OBJECTIVES: To simulate the abrasive potential of an interdental brush when applied with toothpastes and prophylactic gels/solutions in a novel laboratory brushing simulation set-up. METHODS: A brushing device was customized to treat dentin samples mimicking a simplified interdental space with an interdental brush (ISO 2). The brushing, that is, 7200 strokes for 1 h, was performed with artificial saliva (control), a povidone-iodine solution, and slurries of chlorhexidine and fluoride gels as well as three toothpastes with different RDA values ranging from 29 to 100, respectively. The loss of dentin was profilometrically assessed and compared with ANOVA and Fishers LSD. RESULTS: While artificial saliva as control, the solution and the gel slurries showed no measurable dentin loss, toothpastes resulted in a measurable linear surface damage with respect to the actual intrinsic RDA values and ranged from 12.6 to 26.5 µm (p < 0.001). CONCLUSIONS: Any interdental cleaning product should be tailored and carefully instructed. Any over- and misuse should be avoided, which applies especially to the use of interdental brushes in combination with abrasive toothpastes.

The effect of location/site on polished human enamel after mechanical and chemical wear.

OBJECTIVE: To compare profilometry and microhardness of polished occlusal and buccal human enamel following a mechanical and chemical wear regime. METHODS: Enamel from polished human molars were sectioned into buccal and occlusal surfaces and randomly allocated into two groups (n = 10) and then exposed to 0.3 % citric acid at pH 2.7 for 10, 20, 40 and 60 mins each followed by abrasion with non-fluoridated toothpaste for 240 strokes in a reciprocating brushing machine. A white light profilometer with a spot size of 12 um measured mean step-height following each cycle. Microhardness indentations were conducted following the final cycled 60 mins erosion/abrasion using 0.01, 0.02, 0.1, 0.5 and 2.5 kgf indentation load. Statistical disparity were evaluated using a two-way ANOVA and post-hoc Sidak's multiple comparisons tests at α = 0.05. RESULTS: After erosion/abrasion, the mean (SD) step-heights on occlusal and buccal surfaces were not significantly different until 60 mins, when occlusal surfaces exhibited greater step-heights, 32.9 µm (2.8) and 31.1 µm (1.8) and p = 0.02, respectively. Buccal and occlusal microhardness was statistically lower following erosion/abrasion at loads of 0.01 kgf (p = 0.0005) and 0.02 kgf (p = 0.0006) but no significant differences were observed in the microhardness between the surfaces at any loads. CONCLUSION: The occlusal and buccal surfaces were not statistically different for microhardness or step height suggesting the susceptibility to wear is not related to the anatomy and structure of the tooth and is more likely related to other factors such as the environment. CLINICAL SIGNIFICANCE: The study emphasizes that a notable difference in wear between occlusal and buccal enamel surfaces emerges only after prolonged exposure to simultaneous chemical and mechanical stress. This finding necessitates a preventive dental approach that accounts for both the duration of exposure and environmental factors.

A microscopia eletrônica de varredura pode ser usada para medir quantitativamente a rugosidade da dentina? / Can Scanning Electron Microscopy be used to quantitatively measure dentine roughness?

Objective: The aim of this study was to determine if SEM used with imaging software could be used to quantitatively determine the extent of dentine roughness due to tooth-brushing. Material and methods: Flat, polished dentine surfaces were subjected to 25,000 cycles of simulated tooth-brushing at 2 strokes per second with a load of 200 g. At the end of the brushing cycle, dentine surfaces were first assessed using profilometry and then subjected to SEM analysis. Ra (average roughness) readings were obtained for profilometric assessment. Using imaging software, the horizontal distance between adjacent characteristic grooves noted on micrographs was measured, ensuring that the middle of each crest of the associated groove was used as the reference point, the Crest-to-Crest distance (C-C distance). These two parameters were examined statistically for correlation. Results: When Spearman Rank tests were utilized the correlation between average Ra and crest to crest measurements was 0.709 (p <0.01). The Bland Altman plot, however, showed poor agreement between the two test parameters. Conclusion: Further work is needed to validate the use of this methodology in the quantitative assessment of tooth surface loss due to abrasion (AU)

Objetivo: O objetivo deste estudo foi determinar se o MEV usado com software de imagem poderia ser usado para determinar quantitativamente a extensão da rugosidade da dentina devido à escovação dentária. Material e Métodos: Superfícies dentinárias planas e polidas foram submetidas a 25.000 ciclos de escovação dentária simulada a 2 movimentos por segundo com uma carga de 200g. No final do ciclo de escovação, as superfícies dentinárias foram primeiro avaliadas por perfilometria e depois submetidas à análise MEV. Leituras de Ra (rugosidade média) foram obtidas para avaliação perfilométrica. Utilizando um software de imagem, foi medida a distância horizontal entre sulcos característicos adjacentes observados nas micrografias, garantindo que o meio de cada crista do sulco associado fosse usado como ponto de referência, a distância crista a crista (distância CC). Esses dois parâmetros foram examinados estatisticamente para correlação. Resultados: Quando foram utilizados os testes de Spearman Rank, a correlação entre a média de Ra e as medidas de crista a crista foi de 0,709 (p<0,01). O gráfico de Bland Altman, no entanto, mostrou fraca concordância entre os dois parâmetros de teste. Conclusão: Mais trabalhos são necessários para validar o uso desta metodologia na avaliação quantitativa da perda da superfície dentária devido à abrasão(AU)

Longterm abrasive and erosive effect of whitening toothpaste on dentin surface.

PURPOSE: To evaluate the amount of dentin loss following immersion in or toothbrushing with whitening toothpaste (WT) containing hydrogen peroxide (HP) and citric acid (CA). Additionally, the amount of dentin loss after brushing with a WT alone or in combination with a conventional toothpaste was assessed, and the effects of HP and CA solutions on the dentin surface were investigated. METHODS: Bovine dentin specimens (n= 350) were randomly assigned to seven solutions of various compositions as toothpaste: The specimens assigned to each solution were then further divided into five treatment groups (n=10 each) : Group A = 1-hour immersion in each solution (ES); Group B = 10,000 brushing in ES; Group C = 1-hour immersion in ES + 10,000 brushing in ES; Group D = 1-hour immersion in ES + 10,000 brushing in reference slurry (RS); Group E = 10,000 brushing in ES + 10,000 brushing in RS. The amount and pattern of dentin loss were determined, and the surfaces were observed using noncontact profilometry. RESULTS: The WT (pH 5.0) caused lower dentin loss than RS after a single brushing cycle; however, the extent of dentin loss after 1 hour of immersion in the WT was significantly greater than that in the RS. Among the specimens treated with WT, a significant difference in dentin loss was observed between Group C and Groups D and E (P< 0.05) but not between Groups D and E. The surfaces exposed to CAS1, CAPB, and WT exhibited U-shaped patterns of dentin loss after brushing or immersion, whereas a wedge-shaped pattern was observed in those that underwent brushing with the RS. CLINICAL SIGNIFICANCE: The effects (dentin abrasion) of a whitening toothpaste containing hydrogen peroxide and citric acid when used in combination with a conventional toothpaste were similar to those seen with the continuous use of a conventional toothpaste alone.

Envejecimiento dental prematuro en deportistas / Premature dental aging in athletes

El desgaste natural de los dientes ocurre dependiendo de factores como: calidad de la estructura dental, calidad de la saliva, biotipo facial que determina la fuerza de mordida; de acuerdo a estos factores locales bucales se va envejeciendo la dentadura. Pero los deportistas presentan un patrón de desgaste mayor y continuo debido al tipo de deporte que practican, las horas de entrenamiento, el consumo de bebidas con pH ácido, el cepillado dental vigoroso; todos estos factores pueden conducirlos a que desarrollen lesiones no cariosas (AU)

The natural wear of the teeth occurs depending on factors such as: quality of the dental structure, quality of the saliva, facial biotype that determines the bite force, according to these local oral factors, the teeth age. But in athletes they present a pattern of greater and continuous wear due to the type of sport they practice, the hours of training, the consumption of drinks with an acidic pH, vigorous tooth brushing; all these factors can lead them to develop non-carious lesions (AU)

In Vitro Assessment of Different Toothbrush Designs on Enamel Surface Abrasion: A Profilometric Study.

AIM: The purpose of this study was to evaluate the impact of three different toothbrush designs on enamel surface abrasion. MATERIALS AND METHODS: Sixty intact freshly extracted maxillary central incisors were considered for the study. All of the extracted teeth's surfaces were severely trimmed, leaving only the labial surface intact. In the trial, a conventional teeth-whitening dentifrice slurry was utilized. A brushing model was created to deliver uniform force in unidirectional motion. Dontrix Gauge was used to control the tension of the spring. The force was kept constant at 180 ± 20 g. The mounted enamel samples were separated into three groups (20 samples each) at random: group A: toothbrushes have a flat trim bristle design, group B: toothbrushes have a zigzag pattern, and group C: toothbrushes have a bi-level bristle design. For 2 weeks, each sample was brushed twice daily for 2 minutes. A profilometer was used to measure the average surface roughness. RESULTS: After toothbrushing, the maximum mean surface roughness score was found in zigzag pattern group (2.10 ± 0.23), followed by bi-level bristle design group (2.06 ± 0.12) and the least was in the flat trim bristle design group (1.96 ± 0.09). There was a significant difference between the different toothbrush bristle pattern groups (p < 0.001). CONCLUSION: On conclusion, the results of this study showed that, in comparison to toothbrushes with zigzag patterns and bi-level bristle designs, flat trim toothbrush bristle designs cause the least amount of surface abrasion and are relatively safe to use. CLINICAL SIGNIFICANCE: Toothbrushing with toothpaste contributes significantly to dental abrasion. A variety of parameters, including toothpaste abrasivity and concentration, brushing frequency, brushing length, brushing force, and toothbrush bristle stiffness, have the potential to influence the abrasion process of dental hard tissue.

[Aesthetic management of erosive tooth wear using injection molding technique]. / Esteticheskoe lechenie vertikal'noi stiraemosti zubov s ispol'zovaniem in"ektsionnoi tekhniki.

In this article, on the example of a clinical case, the technique of restoring two central teeth in a patient with increased enamel erasability with highly filled fluid composite materials using injection techniques is described. The application of this technique has become possible because the new fluid composites have similar mechanical, physical and aesthetic properties to universal composite materials.

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

PURPOSE: To investigate the effect of the supplementation of energy drinks with green tea extract on abrasive and erosive dentin wear. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSION: The supplementation of energy drinks with green tea extract provide a protective effect against erosive/abrasive wear in vitro.

Interaction between Hexametaphosphate, Other Active Ingredients of Toothpastes, and Erosion-Abrasion in Enamel in vitro.

Sodium hexametaphosphate (HMP) as toothpaste additive is claimed to reduce erosive tooth wear and to stabilize stannous ions. However, little is known about the impact of concentration and its interactions with fluoride (F) or stannous+fluoride ions (F/Sn) on enamel erosion and erosion-abrasion. In a 10 day cyclic in vitro erosion-abrasion model, 320 flat human enamel specimens were divided into ten groups (n = 32 each) and daily subjected to six erosive challenges (0.5% citric acid, 2 min) and two toothpaste suspension applications (2 min, 1:3 F-free toothpaste:mineral-salt solution, 0.23% sodium gluconate). Half of specimens per group were additionally brushed twice/day (200 g, 15 s) during suspension immersion. Nine suspensions contained HMP (0.25%, 1.75%, 3.25%), either on its own or combined with F (373 ppm F-) or F/Sn (800 ppm Sn2+, 373 ppm F-). One suspension contained sodium gluconate only (NegContr). After 10 days, specimens' surfaces were analysed with profilometry, energy dispersive X-ray spectroscopy, and scanning electron microscopy. Tissue loss (µm, mean ± standard deviation) in NegContr was 10.9 ± 2.0 (erosion), 22.2 ± 1.6 (erosion-abrasion). Under erosive conditions, only 0.25% HMP in any combination and 1.75% HMP with F/Sn reduced loss significantly (-28% to -54%); 3.25% HMP without F and F/Sn increased loss significantly (+35%). With additional abrasion, no suspension reduced loss significantly compared to NegContr, instead, in groups without F and F/Sn or with 3.25% HMP loss was increased (+15% to +30%). Conclusively, at higher concentrations, HMP increased erosive tooth wear and seemed to reduce anti-erosive effects of fluoride and stannous ions.

Qualitative Characterization of the Abrasive Component of Charcoal-Containing Toothpastes and the Effect on Dentin Roughness / Caracterización Cualitativa del Componente Abrasivo de las Pastas Dentales que Contienen Carbón Vegetal y la Rugosidad de la Dentina

This study investigated the effect of commercially available whitening toothpastes containing charcoal on dentin. Nine charcoal-containing toothpastes were compared with 3 whitening toothpastes (positive control) and distilled water (negative control). Periodontally hopeless molars were cleaned and washed and the occlusal table removed to expose dentin. The teeth were mounted in auto-polymerizing resin and exposed dentine surfaces polished with water-cooled decreasing grits of silica carbide paper up to 1500 grit. Baseline average roughness (Ra) measurements were taken. Specimens were then mounted in an automatic tooth-brushing machine and brushed for 5000 cycles. Repeat Ra measurements were taken. Specimens were brushed in 5000-cycle increments up to 25,000 cycles with Ra measurements being taken at each time point. Between abrasive challenges specimens were stored in distilled water. All toothpaste samples were sputter coated and examined under a scanning electron microscope to qualify the shape and size of the abrasive components of the formulations. Data were analyzed using a two-way analysis of variance with post hoc Bonferroni. The results demonstrated that the abrasive effect, in terms of increasing Ra, on dentin was noted as early as 5000 cycles for all the tested toothpastes (p<0.05). The effect of continued brushing showed an overall cumulative effect on dentine roughness up to 25000 cycles. When toothpastes were compared between groups at each time-point, dentin specimens brushed with Pursito were statistically similar to the control group. At 25,000 cycles all dentin samples were significantly rougher compared to Pursito and the control groups. It may be concluded that all the tested toothpastes have an abrasive effect on dentin surfaces.

Este estudio investigó el efecto sobre la dentina de las pastas dentales blanqueadoras disponibles en el mercado que contienen carbón vegetal. Se compararon nueve dentífricos que contenían carbón vegetal con 3 dentífricos blanqueadores (control positivo) y agua destilada (control negativo). Los molares sin material periodontal se limpiaron y lavaron y se retiró la tabla oclusal para exponer la dentina. Los dientes se montaron en resina autopolimerizable y las superficies expuestas de la dentina se pulieron con papel de carburo de sílice de grano decreciente enfriado con agua hasta grano 1500. Se tomaron medidas de rugosidad promedio (Ra) de referencia. Luego, las muestras se montaron en una máquina automática de cepillado de dientes y se cepillaron durante 5000 ciclos. Se tomaron medidas repetidas de Ra. Las muestras se cepillaron en incrementos de 5000 ciclos hasta 25 000 ciclos y se tomaron medidas de Ra en cada punto de tiempo. Entre periodos abrasivos, las muestras se almacenaron en agua destilada. Todas las muestras de pasta de dientes se recubrieron por pulverización catódica y se examinaron bajo un microscopio electrónico de barrido para calificar la forma y el tamaño de los componentes abrasivos de las formulaciones. Los datos se analizaron utilizando un análisis de varianza de dos vías de Bonferroni post hoc. Los resultados demostraron que el efecto abrasivo, en términos de aumento de Ra, sobre la dentina se notó ya en 5000 ciclos para todas las pastas dentales probadas (p<0,05). El efecto del cepillado continuo mostró un efecto acumulativo general sobre la rugosidad de la dentina hasta 25.000 ciclos. Cuando se compararon las pastas dentales entre los grupos en cada momento, las muestras de dentina cepilladas con Pursito fueron estadísticamente similares al grupo de control. A los 25.000 ciclos, todas las muestras de dentina eran significativamente más ásperas en comparación con Pursito y los grupos controles. Se puede concluir que todas las pastas dentales probadas tienen un efecto abrasivo sobre las superficies dentinarias.

The subsurface lesion in erosive tooth wear.

OBJECTIVES: This study compared the surface change on natural and polished enamel exposed to a joint mechanical and chemical wear regimen. METHODS: Human enamel samples were randomly assigned to natural (n = 30) or polished (n = 30) groups, subjected to erosion (n = 10, 0.3% citric acid, 5 min), abrasion (n = 10, 30 s), or a combination (n = 10). Wear in the form of step height was measured with a non-contact profilometer, and surface changes were inspected with SEM on selected sections. Data was normalised and underwent repeated measures MANOVA, accounting for substrate and erosive challenge as independent variables, with Bonferroni correction for significant post hoc interactions. RESULTS: After four cycles, polished samples had mean step heights of 3.08 (0.40) µm after erosion and 4.08 (0.37) µm after erosion/abrasion. For natural samples, these measurements were 1.52 (0.22) µm and 3.62 (0.39) µm, respectively. Natural surfaces displayed less wear than polished surfaces under erosion-only conditions (p<0.0001), but the difference disappeared with added abrasion. SEM revealed a shallow subsurface layer for polished surfaces and natural ones undergoing only erosion. However, natural surfaces exposed to both erosion and abrasion showed deeper subsurface changes up to 50 µm. CONCLUSION: Natural enamel, when exposed to erosion alone, showed less wear and minimal subsurface alterations. But with added abrasion, natural enamel surfaces saw increased wear and notable subsurface changes compared to polished ones. CLINICAL SIGNIFICANCE: The pronounced subsurface lesions observed on eroded/abraded natural enamel surfaces highlight how combined wear challenges may accelerate tooth tissue loss.

Susceptibility of fluorotic enamel to dental erosion-abrasion.

Dental hard tissue conditions can be of pre- or post-eruptive nature, such as enamel fluorosis and erosive tooth wear (ETW), respectively. Dental enamel fluorosis is caused by the chronic and excessive intake of fluoride during enamel development, leading to increased fluoride concentration and increased porosity. ETW has become a common clinical condition and often impairs dental function and aesthetics. This in vitro study tested the hypothesis that fluorotic enamel presents different susceptibility to dental erosion-abrasion. It consisted of a 3×3×2 factorial design, considering a) fluorosis severity: sound (TF0), mild (TF1-2), moderate (TF3-4); b) abrasive challenge: low, medium, and high; and c) erosive challenge: yes or no. A total of 144 human teeth were selected according to the three fluorosis severity levels (n=48), and subdivided into six groups (n = 8) generated by the association of the different erosive and abrasive challenges. Enamel blocks (4×4 mm) were prepared from each tooth and their natural enamel surfaces subjected to an erosion-abrasion cycling model. After cycling, the depth of the lesions in enamel was assessed by profilometry. ANOVA showed that the three-way and two-way interactions among the factors were not significant (p > 0.20). Enamel fluorosis level (p=0.638) and abrasion level (p = 0.390) had no significant effect on lesion depth. Acid exposure caused significantly more enamel surface loss than water (p < 0.001). Considering the limitations of this in vitro study, fluorosis did not affect the susceptibility of enamel to dental erosion-abrasion.