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.

Dentin abrasion using whitening toothpaste with various hydrogen peroxide concentrations.

PURPOSE: To compare the amount of abrasion of four whitening toothpastes, two conventional toothpastes, and seven experimental toothpastes with varying concentrations of hydrogen peroxide. METHODS: Bovine dentin specimens were treated with the four whitening toothpastes (containing three different concentrations of hydrogen peroxide: 0.75%, 1.50%, and 2.80%), two conventional toothpastes without hydrogen peroxide, seven experimental toothpastes (concentrations of hydrogen peroxide: 0.75%, 1.50%, 3.0%, 4.50%, 6.0%, 7.50%, and 9.0%), and distilled water. After 10,000 strokes of toothbrushing, the amount of abrasion on the dentin surface was measured with a contactless 3D surface profiler (n= 8). The pH of all solutions, the weight percentages of the particles, and the component of particles in the toothpaste were analyzed. The correlations between the dentin abrasion, pH, and weight percentages of the particles in the toothpastes were investigated. RESULTS: The amount of abrasion of the two conventional toothpastes were 1.1-3.6 times higher than those of the four whitening toothpastes. Likewise, the pH of the conventional toothpaste was higher than those of the other whitening toothpastes. No significant differences were found among the four whitening toothpastes. The four whitening toothpastes consisted of a relatively lower weight percentage of particles compared to the two conventional toothpastes. A strong positive correlation was observed between the dentin abrasion and the weight percentages of the particles (r= 0.913; P< 0.05). Furthermore, no significant differences in the amount of abrasion were observed between the specimens treated with seven experimental toothpastes and those treated with distilled water. CLINICAL SIGNIFICANCE: The whitening toothpastes containing less than 9% hydrogen peroxide did not seem to harm the dentin surface significantly. These findings can serve as a reference for consumers, patients, and dental professionals.

Comparison of Profilometric and Microindentation Analyses for Determining the Impact of Saliva on the Abrasion of Initially Eroded Enamel.

The aim of this in vitro study was to investigate the impact of saliva on the abrasion of eroded enamel using two measuring methods. A total of 80 bovine enamel specimens from 20 bovine incisors were allocated to four experimental groups (n = 20 specimens per group). After baseline surface microhardness (SMH) measurements and profilometry all specimens were subjected to erosion (2 min, 1% citric acid, pH: 3.6, 37°C). SMH was determined again, and the depths of the Knoop indentations were calculated. Thereafter, specimens were incubated in human saliva (group 1 - no incubation/control, group 2 - 0.5 h, group 3 - 1 h, group 4 - 2 h) before toothbrush abrasion was performed. After final SMH measurements and profilometry, indentations were remeasured, and surface loss was calculated. SMH did not return to baseline values regardless of the length of saliva incubation. Further, an irreversible substance loss was observed for all specimens. With the indentation method, significantly (p < 0.05) more substance loss was found for controls (least square means ± standard error of 198 ± 19 nm) than for groups 2-4 (110 ± 10, 114 ± 11, and 105 ± 14 nm). Profilometric assessment showed significantly more substance loss for controls (122 ± 8 nm) than for group 4 (106 ± 5 nm). Intraclass correlation for interrater reliability between measurement methods was low (0.21, CI: 0.1-0.3), indicating poor agreement. Exposure of eroded enamel to saliva for up to 2 h could not re-establish the original SMH. The amount of measured substance loss depended on the measurement method applied.

Sodium bicarbonate: A review and its uses in dentistry.

Denture stomatitis, periodontitis, and peri-implantitis are the growing problems in restorative dentistry. Chemicals play an important role as an adjuvant to mechanical cleaning of teeth, implants, surrounding tissues, and prostheses. Current mouth rinses are reported to affect the tissues and prostheses if used on a long-term basis. Sodium bicarbonate, the common baking soda, has been reported to be versatile. A search of the resources through Medline and Google Scholar was made to understand the current status of the mouth rinses and the use of sodium bicarbonate. Different MeSH and search criteria were used for the different search engines. Baking soda, being a common household item, with its ready availability, safety, minimal abrasivity, and bactericidal property makes it a patient-friendly mouthwash, component in the dentifrice, or chewing gum, which can be used on a long-term basis as an adjunct virtually free of any side effects.

Impact of toothbrushing frequency and toothpaste fluoride/abrasivity levels on incipient artificial caries lesion abrasion.

OBJECTIVES: To investigate the interplay among brushing frequency, dentifrice slurry abrasivity, and fluoride content on the surface loss (SL) of incipient enamel caries-like lesions. METHODS: Lesions were created in 96 bovine enamel specimens (5 × 5 mm) using methylcellulose acid gel. Specimens were randomly allocated to 12 groups (n = 8), resulting from the association of three experimental factors: (1) slurry abrasive level [low: REA = 4/RDA = 69 and high: REA = 7/RDA = 208], (2) fluoride concentration [275 and 1250 ppm F as NaF], and (3) brushing frequency [1, 2 and 3× daily]. Specimens were kept in artificial saliva in between brushings and overnight. SL was determined by optical profilometry after lesion creation, 1, 3, 5, and 7 days. Data was analyzed with repeated measures ANOVA and Tukey's tests (α = 0.05). RESULTS: High abrasive slurry caused significantly more SL than low with 275 ppm (p < 0.001) but not with 1250 ppm fluoride (p = 0.34). Fluoride at 275 ppm had significantly more SL than 1250 ppm with high abrasive slurry after 7 days (p = 0.008). Brushing 1×/day had significantly less SL than 3×/day after 7 days with high abrasive slurry (p = 0.016), especially in the 275 ppm fluoride groups. CONCLUSIONS: Higher fluoride concentration increased protection against the deleterious effect of high abrasive slurry. SL was higher if brushing was performed more than twice daily especially in low fluoride groups. CLINICAL SIGNIFICANCE: Highly abrasive toothpaste formulations might cause more surface wear to incipient caries lesions, especially at higher brushing frequencies. Increasing the fluoride content may be beneficial at these circumstances.

A novel approach to study in situ enamel erosion and abrasion lesions.

OBJECTIVES: This study investigated previous hypotheses that the tongue can abrade acid softened/eroded enamel surfaces. METHODS: Twelve upper removable appliances each retaining 2 anterior and 2 posterior human enamel specimens were constructed. Each specimen was exposed to acid on both surfaces, but only one surface was allowed contact with the tongue. Therefore, 96 surfaces were assessed. Appliances were worn from 9.30 to 17.00 Monday to Friday for 22days. Acid eroded lesions were created by immersing the specimens for 5min in 50ml orange juice three times daily. Enamel loss was measured using Quantitative light- induced fluorescence (QLF) and Non- contact profilometry (NCLP) and the differences (D) between tongue (Dt) and palate facing (DP) surfaces determined. RESULTS: %ΔFD(t-p) from the two anterior specimens were greater than from those placed posteriorly with mean values of 15.9% (±9.1) and 14.4% (±8.4), 5.6% (±8.7) and 4.5% (±6.6) respectively. Similarly, NCLP data showed anterior specimens had greater differences for mean step height (MSH) between tongue- facing and the palate- facing (control) surfaces than posterior specimens. MSHD(t-p) values were 59.4µm (±30.3) for anterior tongue facing surfaces and 55.5µm (±29.4) for posterior palate facing surfaces. For the posterior specimens MSH was 48.1µm (±26.1) and 51.7µm (±30.4) respectively (p<0.05). CONCLUSION: The greater enamel surface loss of the anterior specimens demonstrates that abrasion by the tongue on acid softened/eroded enamel in situ is likely.

Effect of Whitening Toothpastes on Dentin Abrasion: An In Vitro Study.

PURPOSE: To compare the effect of toothbrushing abrasion with hydrated silica-based whitening and regular toothpastes on root dentin using contact profilometry. MATERIALS AND METHODS: Ninety dentin specimens (4 x 4 x 2 mm) were randomly divided into five experimental groups (n = 18) according to the toothpaste: three whitening (W1, W2 and W3) and two regular toothpastes (R1 and R2) produced by two different manufacturers. Using a brushing machine, each specimen was brushed with a constant load of 300 g for 2500 cycles (4.5 cycles/s). The toothpastes were diluted at a ratio of 1:3 w/w (dentifrice:distilled water). The brush diamond tip of the profilometer moved at a constant speed of 0.05 mm/s with a force of 0.7 mN. RESULTS: The average value of brushing abrasion in µm (mean ± SD) was obtained from five consecutive measurements of each specimen: W1 = 8.86 ± 1.58, W2 = 7.59 ± 1.04, W3 = 8.27 ± 2.39, R1 = 2.89 ± 1.05 and R2= 2.94 ± 1.29. There was a significant difference between groups (ANOVA, p<0.0001). Post-hoc Tukey's test for multiple comparisons showed differences between all the whitening and regular toothpastes, but not among the whitening nor among the regular toothpastes. CONCLUSION: The whitening toothpastes tested can cause more dentin abrasion than the regular ones.

Dentin abrasivity of various desensitizing toothpastes.

BACKGROUND: The aim of this study was to compare the abrasivity of various commercially available toothpastes that claim to reduce dentin hypersensitivity. METHODS: Dentin discs were prepared from 70 human extracted molars. The discs were etched with lemon juice for 5 min, and one half of the discs were covered with aluminum tape. Following this, they were brushed with 6 different toothpastes, simulating a total brushing time of 6 months. As a negative control, discs were brushed with tap water only. The toothpastes contained pro-arginine and calcium carbonate, strontium acetate, stannous fluoride, zinc carbonate and hydroxyapatite, new silica, or tetrapotassium pyrophosphate and hydroxyapatite. After brushing, the height differences between the control halves and the brushed halves were determined with a profilometer and statistically compared using a Mann-Whitney U test for independent variables. RESULTS: A significant difference (p < 0.001) in height difference between the controls and the toothpaste-treated samples was found in all cases, except for the stannous fluoride-containing toothpaste (p = 0.583). The highest abrasion was found in the toothpaste containing zinc carbonate and hydroxyapatite, and the lowest was found in the toothpaste containing pro-arginine and calcium carbonate. CONCLUSIONS: Desensitizing toothpastes with different desensitizing ingredients have different levels of abrasivity, which may have a negative effect on their desensitizing abilities over a long period of time.

Effects of Erosion Protocol Design on Erosion/Abrasion Study Outcome and on Active Agent (NaF and SnF2) Efficacy.

There is no standard for testing anti-erosive/anti-abrasive agents, making the assessment and comparison of study results difficult. Factors which are varied in study designs are amongst others the erosive medium regarding concentration and pH or movement type of acid. The present study therefore investigated the impact of these factors on dimension of tissue loss and on efficacy of active agents used as anti-erosive/anti-abrasive therapeutics. In 8 experiments, consisting of 8 groups each (n = 20 each), resulting in a total of 64 groups, enamel specimens were demineralised (10 days, 6 × 2 min/day) using different acids (1, 0.5 and 0.3% citric acid at native pH 2.3, 2.5 and 2.8, respectively, and 0.3% citric acid adjusted to pH 3.6) with two different movement types (jerky or smooth). Specimens were immersed (2 × 2 min/day) in slurries of 1,450 ppm F- toothpaste (NaF), 1,450 ppm F- and 3,436 ppm Sn2+ toothpaste (NaF/SnF2), 970 ppm F- and 3,000 ppm Sn2+ gel (SnF2) or placebo, or were additionally brushed during immersion (15 s, 200 g). All groups were in between stored in a mineral salt solution. Tissue loss was determined profilometrically. Movement type, pH and concentration of acid had a substantial impact on study outcome. The combination of jerky movement and concentrated acid masked, to some extent, differences between erosive and erosive-abrasive tissue loss. The acid at low concentration (0.3%), independent of pH, was too mild to produce any tissue loss. The model with the best ability to demonstrate effects of abrasive impacts and active agents used the 1% acid concentration combined with smooth acid movements.

In vitro assessment of a toothpaste range specifically designed for children.

OBJECTIVE: To evaluate the ability of a range of low abrasivity experimental toothpastes designed for use by children at different stages of their development (typically ages 0-2 years, 3-5 years and 6+ years) to promote fluoride uptake and remineralisation of artificial caries lesions. METHODS: pH cycling study: demineralised human permanent enamel specimens were subjected to a daily pH cycling regime consisting of four 1-minute treatments with toothpaste slurries, a 4-hour acid challenge and remineralisation in pooled whole human saliva. Surface microhardness (SMH) was measured at baseline, 10 days and 20 days, and the fluoride content determined at 20 days. Enamel Fluoride Uptake (EFU): these studies were based on Method #40 described in the US Food and Drug Administration (FDA) testing procedures. Abrasivity: relative enamel abrasivity (REA) and relative dentine abrasivity (RDA) were measured using the Hefferren abrasivity test. Bioavailable fluoride: the bioavailable fluoride was determined for all experimental toothpastes from slurries of one part toothpaste plus 10 parts deionised water. RESULTS: Enamel remineralisation measured by changes in SMH correlated with enamel fluoride content. A statistically significant fluoride dose response was observed for all toothpastes tested across all age groups (P < 0.05). The fluoride content of specimens in the pH cycling model correlated with the EFU testing results. The enamel and dentine abrasivities were low and the level of bioavailable fluoride was high for all experimental toothpastes. CONCLUSION: A series of low abrasivity experimental toothpastes were developed which were effective at promoting fluoride uptake and remineralisation of artificial caries lesions.

Avaliação da resistência de união de reparos de resina composta, utilizando-se diferentes tratamentos de superfície / Evaluation of microtensile bond strength of composite resin repair using different surface treatments

Objetivo: Avaliar a resistência de união de reparos de restaurações em resina composta utilizando-se diferentes tratamentos de superfície. Materiais e Métodos: Foram utilizadas 180 amostras de resina composta Tetric Ceram® (Ivoclar/Vivadent), distribuídas em 9 grupos (n=20/grupo). No momento do reparo, cada grupo recebeu tratamento de superfície específico: ácido fosfórico a 37% (Ivoclar/Vivadent); ácido hidrofluorídrico a 10% (Dentsply) ou microjateamento com partículas de óxido de alumínio de 50μm (Micro Jato VH®). Em seguida, aplicou-se o sistema adesivo Heliobond® (Ivoclar/Vivadent), associado ou não ao agente silanizadorMonobond-S® (Ivoclar/Vivadent). Foram também confeccionados espécimes que não sofreram nenhum tipo de reparo (grupo controle). Os espécimes ficaram armazenados em água deionizada por 18 meses. Posteriormente cada amostra foi submetida ao teste de resistência de união à microtração em máquina de ensaio universal (EMIC DL500BF), a uma velocidade de 0,5 mm/minuto. Os dados obtidos em MPa foram submetidos a avaliação da normalidade da variável microtração por meio do teste Kolmogorov-Smirnov. Considerando quea variável não apresentou distribuição normal (p<0,001) foram realizados os testes de Kruskal-Wallis e Mann-Whitney. O valor de p considerado foi menor que 0,05, exceto, quando se utilizou da correção de Bonferroni(p<0,00138). Resultados: Os espécimes do grupo controle apresentaram resistência à tração estatisticamente superior em relação aos demais grupos. O emprego do ácido fosfórico e posterior inserção do sistema adesivo apresentou resultados estatisticamente significante em relação aos demais grupos reparados. Conclusões: A resistência coesiva da resina composta foi superior às outras técnicas de reparo utilizadas. O emprego do ácido fosfórico e posterior inserção do sistema adesivo demonstrou ser o tratamento ideal para o reparo derestaurações em resina composta.

Erosion and abrasion of enamel and dentin associated with at-home bleaching: an in vitro study.

BACKGROUND: Bleaching and erosive processes have been reported to soften dental surfaces, possibly increasing their susceptibility to toothbrush abrasion. The authors conducted an investigation of the effect on enamel and dentin of the interaction among bleaching, erosion and dentifrice abrasivity. METHODS: The authors prepared specimens of human enamel and root dentin and randomly divided them into eight groups that underwent 10 percent carbamide peroxide bleaching, erosion and dentifrice abrasion. The authors submitted the specimens to cycles of erosion, toothbrushing and bleaching for five days. They determined the change in surface loss by means of profilometry. RESULTS: Dental erosion and the more abrasive dentifrice increased toothbrushing wear on enamel surfaces, while bleaching showed no deleterious effect. Dentin wear also increased after subjection to erosion and use of the more abrasive dentifrice. Bleaching increased surface loss on noneroded dentin and decreased loss on eroded dentin when it was brushed with the less abrasive dentifrice. CONCLUSION: Bleaching did not increase the susceptibility of enamel to erosive and abrasive wear, regardless of the dentifrice used. Dentin wear was modulated by the interaction of bleaching, erosion and dentifrice. CLINICAL IMPLICATIONS: Bleaching with 10 percent carbamide peroxide does not increase erosive and abrasive wear of enamel. However, it may change dentin's abrasive wear, depending on erosive and abrasive challenges.

Abrasive wear of conventional glass ionomer cements / Desgaste abrasivo de cimentos de ionômetro de vidro convencionais

Este trabalho tem por finalidade avaliar a resistência abrasiva de 3 diferentes marcas de cimento de ionômero de vidro (CIV) restauradores, do tipo convencional, disponíveis no mercado nacional. Para isso foi utilizado o teste de agressividade, onde um disco dinâmico revestido com porcelana desgasta, em condições adequadamente estabelecidas, um disco estático revestido com o material restaurador estudado. Neste método valores menones de agressividade indicam maior resistência ao desgaste abrasivo. Foram confeccionados 24 corpos de provas, sendo 8 para cada marca. As marcas de CIV avaliadas foram: Vidrion R (fabricado pela empresa brasileira SSWhite), Ketac Fil Plus (fabricado pela empresa americana 3M ESPE) e Fuji IX GP (fabricado pela empresa japonesa GC), que posteriormente foi substituído pela marca Vitro Fill (fabricado pela empresa brasileira DFL Indústria e Comércio Ltda.). Os materiais foram confeccionados de acordo com as instruções dos respectivosfabricantes. Os testes foram executados em duas etapas: na primeira não houve controle do tempo de exposição ao ambiente, e as análises dos dados revelaram grande influência desta exposição na propriedade de resistência ao desgaste abrasivo. Em uma segunda etapa, o tempo de exposição foi rigidamente controlado, assim como a umidade do ar e a temperatura ambiente, desde a confecçãodos corpos de prova até a finalização dos ensaios, otendo-se assim os resultados desejados. Deste modo, além da classificação de cada marca de acordo com a resistência ao desgaste abrasivo, também foi mostrado que o tempo de exposição deste material ao ar ambiente deve receber atenção especial em trabalhos que versem sobre propriedades mecânicas do cimento de ionômero de vidro.

An evaluation was made of the abrasive strenght of three different brands of conventional glass ionomer cement (GIC) for dental restoration available on the Brazilian market. The evaluation was based on an agressiveness assay in which, under pre established conditions, a disk coated with porcelain wears down a static disk coated with the restorative material under study. According to this method, low agressiveness values indicate high abrasive wear resistance...

The effect of anti-sensitivity dentifrices on brushing abrasion of eroded dentin in vitro.

OBJECTIVE: To investigate the abrasive effects of three marketed anti-sensitivity, and one marketed regular dentifrice on dentin, using an erosion-abrasion in vitro model. METHODS: Standardized human dentin specimens were prepared and exposed to cycles of erosion, remineralization, and tooth brushing, utilizing the four commercially available dentifrices. Dentin surface loss was then measured by optical profilometry after a total of nine complete cycles. The RDA and pH values of the dentifrices were also measured to assist in the interpretation of results. RESULTS: Profilometry showed significantly greater dentin surface loss for both Colgate Sensitive Fresh Stripe and Colgate Sensitive Multi Protection when compared with Sensodyne Total Protection or Crest Cavity Protection dentifrices. The abrasive level of dentifrices correlated positively (r-squared = 0.66; p < 0.05) with dentin surface loss. CONCLUSION: This study demonstrated that the abrasivity of dentifrices can have a significant effect on the wear of eroded dentin in vitro.

The measurement in vitro of dentine abrasion by toothpastes.

OBJECTIVES: To investigate the in vitro dentine wear after tooth brushing with a range of nine toothpastes. METHODS: 70 bovine dentine blocks (aproximately 1 cm long) were used. Specimens were brushed in vitro with toothpastes with a range of abrasive. All the specimens were submitted to 10,000 brushing cycles with a 200g load. Initial and final weight and profile data were obtained using an analytical scale and a profile projector respectively. RESULTS: Significant differences between the test products were found (p < 0.05). The mean dentine wear ranged from 0.039 to 0.006g and 0.502 to 0.185mm, with the highest wear for the whitening toothpastes. CONCLUSIONS: This study demonstrated that the type of toothpaste abrasive can contribute to dentine wear.

Review of the extrinsic stain removal and enamel/dentine abrasion by a calcium carbonate and perlite containing whitening toothpaste.

There has been an increase in the demand from consumers and patients for products that whiten teeth. To meet this demand, a whitening toothpaste containing calcium carbonate and perlite as the abrasive system and an efficacious fluoride source has recently been launched. The aim of the current paper is to review the toothpaste's stain removal efficacy and its effects on enamel and dentine wear. It has been shown to be effective at removing model extrinsic stain in vitro. Further, it has been shown to be more effective in removing naturally occurring extrinsic tooth stain than a silica non-whitening control toothpaste after two weeks of twice daily brushing in a parallel group, double-blind clinical study using 152 adult volunteers. In addition, the enhanced whitening effect did not give a clinically relevant level of wear to enamel or a significant increase in dentine wear compared to marketed non-whitening toothpaste formulations, as shown by using an in situ type model with ex vivo brushing.

Wear of dentine in vitro by toothpaste abrasives and detergents alone and combined.

AIM: To measure in vitro the abrasion of dentine by toothpaste detergents and abrasives alone and combined. MATERIALS AND METHODS: Detergents used were tego betain, sodium lauryl sulphate (SLS), adinol and pluronic diluted to 1% w/v. Abrasives were three artificial silicas, tixosil 73 and 123 and Zeodent 113, and calcium carbonate used at 2.5% w/v. Flat human dentine specimens were brushed with aqueous detergent solutions or abrasive slurries, detergent abrasive slurries and water for 20,000 brush strokes. Dentine loss was measured by non-contacting profilometry at 10,000 and 20,000 strokes. Silica particle size distribution was measured by laser deflection. RESULTS: Loss of dentine occurred with all detergents, abrasives and detergent abrasion combinations, but was not linear with number of brush strokes. Water appeared to remove the smear layer only, but all detergents exceeded the predicted smear layer thickness. The silica abrasives differed in abrasion properties despite similar particle size distribution. Different detergents modulated the abrasives actions in mainly positive or mainly negative directions. CONCLUSIONS: Detergents appear able to attack the dentine surface to produce wear. Abrasives vary considerably in wear produced under similar conditions. Detergents modulate the effect of abrasives in a way that may reflect the rheological properties of the mixture.

In vitro toothbrush-dentifrice abrasion of two restorative composites.

BACKGROUND: Surface wear can be a problem with directly placed composites. PURPOSE: This study evaluated the in vitro wear and surface roughness of two composites at different cycle intervals after being subjected to toothbrush-dentifrice abrasion. MATERIALS AND METHODS: Twenty specimens of a microhybrid, Filtek Z250 (3M ESPE, St. Paul, MN, USA), and a nanofill composite, Filtek Supreme (3M ESPE), were prepared according to the manufacturer's directions. Each specimen was subjected to toothbrush-dentifrice abrasion (250 g vertical load) using a deionized water-dentifrice slurry (Close-Up, Lever Ponds Ltd., La Lucia, ZA) and toothbrush heads (Oral-B 40, Oral-B Laboratories, Delmont, CA, USA). A brushing sequence of 10,000, 20,000, 50,000, and 100,000 strokes was performed for all samples at a rate of 1.5 Hz. At baseline and each cycle interval, a surface profilometer was used to determine average surface roughness, Ra. At the same intervals, vertical loss of material was measured with a precision micrometer. Data were analyzed using repeated-measures analysis of variance at p value .05. Analyses with atomic force microscopy (AFM) and scanning electron microscopy (SEM) were also performed. RESULTS: After 20,000, 50,000, and 100,000 cycles, Filtek Supreme showed less significant wear than Z250. Filtek Supreme demonstrated higher surface roughness than Z250 after 50,000 and 100,000 cycles. However, AFM and SEM images indicated a more uniform surface topography for Filtek Supreme than for Z250. Abrasion wear and surface roughness increased with each cycle interval for both materials. CONCLUSIONS: Although the initial performance of both materials was similar, a greater number of brushing cycles revealed differences between the wear resistance and generated surface roughness of the materials. CLINICAL SIGNIFICANCE: The wear resistance and roughness results of Filtek Supreme suggest that it is suitable for clinical use, mainly in areas that are more subject to abrasive wear, such as Class V restorations.

Tooth wear: diet analysis and advice.

Diet analysis and advice for patients with tooth wear is potentially the most logical intervention to arrest attrition, erosion and abrasion. It is saliva that protects the teeth against corrosion by the acids which soften enamel and make it susceptible to wear. Thus the lifestyles and diet of patients at risk need to be analysed for sources of acid and reasons for lost salivary protection. Medical conditions which put patients at risk of tooth wear are principally: asthma, bulimia nervosa, caffeine addiction, diabetes mellitus, exercise dehydration, functional depression, gastroesophageal reflux in alcoholism, hypertension and syndromes with salivary hypofunction. The sources of acid are various, but loss of salivary protection is the common theme. In healthy young Australians, soft drinks are the main source of acid, and exercise dehydration the main reason for loss of salivary protection. In the medically compromised, diet acids and gastroesophageal reflux are the sources, but medications are the main reasons for lost salivary protection. Diet advice for patients with tooth wear must: promote a healthy lifestyle and diet strategy that conserves the teeth by natural means of salivary stimulation; and address the specific needs of the patients' oral and medical conditions. Individualised, patient-empowering erosion WATCH strategies; on Water, Acid, Taste, Calcium and Health, are urgently required to combat the emerging epidemic of tooth wear currently being experienced in westernised societies.

[The comparative study of the effect of silica and calcium carbonate based dentifrice on dentine abrasives in vitro].

PURPOSE: To evaluate the effect of Silica (SiO(2)) and Calcium Carbonate (CaCO(3)) based dentifrice on their dentine abrasives. METHODS: Microscope, environmental electron scanning electron microscope (SEM) and radioactive Dentine Abrasion (RDA) assay were used to quantitatively measure the wear of dentine. RESULTS: The mechanical brushing assay showed severe dentine abrasion with CaCO(3) based dentifrices. There were only minor scratches on the specimens brushed with SiO(2) dentifrices. Analysis of the thin section by SEM after exposure to dentifrices showed that NaF/SiO(2) produced significant remineralization whereas MFP/CaCO(3) system resulted in little remineralization. RDA values were 86.17 and 98.61 for SiO(2) based dentifrices and 222.85 and 253.84 for CaCO(3) based dentifrices, respectively. The morphology of the irregular shaped CaCO(3) with sharp points/edges further explained the brushing and RDA results. CONCLUSION: These results indicate that abrasive in dentifrice, e.g. CaCO(3), can cause severe abrasion of dentine in vitro.