Abrasivity

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Jamal Rostami - One of the best experts on this subject based on the ideXlab platform.

  • introduction to rock and soil Abrasivity index rsai
    Wear, 2019
    Co-Authors: Mohsen Mosleh, Wei Hu, Jamal Rostami
    Abstract:

    Abstract Characterizing the abrasiveness of rock and soil and developing predictive models for wear of various tools that interact with such geo-materials is critical in selection of best tool materials for applications in earthmoving, drilling, mining, construction, tunneling, and agricultural industries. This paper introduces a Rock and Soil Abrasivity Index (RSAI), utilizes the abrasive wear theory for defining the parameters and examines a testing method for quantitative assessment of the index. The test method measures the wear mass of a target tool material (i.e. steel or hard facing) while it is pressed against the crushed rock or soil medium in a relative motion under high contact stresses based on a defined test protocol for reliability and repeatability. The RSAI is defined as the product of wear volume and hardness of tool divided by the work or energy deployed to overcome frictional forces, as measured by the torque in the device. The RSAI is expected to vary in the 0–100 range for the softest to the hardest possible rock and soil samples and conditions. The RSAI for various soil and crushed rock samples were experimentally determined and presented. Also, the correlation between the RSAI, Cerchar Abrasion Index (CAI) and Soil Abrasion Test (SAT) value, as the most common forms of abrasion testing of soil and rock is discussed.

  • effects of rock water content on cerchar Abrasivity index
    Wear, 2016
    Co-Authors: M Abu Z Bakar, Y. Majeed, Jamal Rostami
    Abstract:

    Cerchar Abrasivity Index (CAI) has been commonly used to represent rock abrasion for estimation of tool wear in rock excavation applications. This test is a simple and effective measure of rock abrasion but operating parameters can impact its results. This paper focuses on the influence of water saturation on CAI values based on laboratory testing of 33 sedimentary rock units collected from different regions of Pakistan. The tests include CAI measurements as well as engineering rock properties on both dry and saturated rocks. It was found that overall 79% of CERCHAR Abrasivity index values measured on saturated rock surfaces “CAIsat” were less than the CERCHAR Abrasivity index values measured on dry rock surfaces “CAIdry”. Meanwhile, 52% of CAIsat values showed significant reduction from CAIdry values in the statistical analysis of CAI results with significance level of 15% (α=0.15). Regression analysis was used to correlate CAIsat values with CAIdry, normally measured in CERCHAR testing. The proposed formula can be used to estimate CAIsat from result of laboratory testing where CAI reported is often CAIdry. This could lead into more accurate estimation of tool wear and related adjustments when CAI is used for estimation of tool wear when excavation is done under wet conditions. Multiple regression was also used to establish a predictive model of CAIsat with petrographical, wear indices and geotechnical rock properties of saturated rock samples. In addition, the validity of correlations of CAI with rock properties that are already published was evaluated.

  • study of dominant factors affecting cerchar Abrasivity index
    Rock Mechanics and Rock Engineering, 2014
    Co-Authors: Jamal Rostami, Amireza Ghasemi, Ehsan Alavi Gharahbagh, Cihan Dogruoz, Filip Dahl
    Abstract:

    The Cerchar abrasion index is commonly used to represent rock abrasion for estimation of bit life and wear in various mining and tunneling applications. Although the test is simple and fast, there are some discrepancies in the test results related to the equipment used, condition of the rock surface, operator skills, and procedures used in conducting and measuring the wear surface. This paper focuses on the background of the test and examines the influence of various parameters on Cerchar testing including pin hardness, surface condition of specimens, petrographical and geomechanical properties, test speed, applied load, and method of measuring wear surface. Results of Cerchar tests on a set of rock specimens performed at different laboratories are presented to examine repeatability of the tests. In addition, the preliminary results of testing with a new device as a potential alternative testing system for rock Abrasivity measurement are discussed.

  • continuous monitoring of pin tip wear and penetration into rock surface using a new cerchar Abrasivity testing device
    Rock Mechanics and Rock Engineering, 2014
    Co-Authors: Mohammadtaghi Hamzaban, Hossein Memarian, Jamal Rostami
    Abstract:

    Evaluation of rock Abrasivity is important when utilizing mechanized excavation in various mining and civil projects in hard rock. This is due to the need for proper selection of the rock cutting tools, estimation of the tool wear, machine downtime for cutter change, and costs. The Cerchar Abrasion Index (CAI) test is one of the simplest and most widely used methods for evaluating rock Abrasivity. In this study, a new device for the determination of frictional forces and depth of pin penetration into the rock surface during a Cerchar test is discussed. The measured parameters were used to develop an analytical model for calculation of the size of the wear flat (and hence a continuous measure of CAI as the pin moves over the sample) and pin tip penetration into the rock during the test. Based on this model, continuous curves of CAI changes and pin tip penetration into the rock were plotted. Results of the model were used for introduction of a new parameter describing rock–pin interaction and classification of rock abrasion.

Yiming Li - One of the best experts on this subject based on the ideXlab platform.

  • Stain removal and whitening by baking soda dentifrice: A review of literature.
    Journal of the American Dental Association (1939), 2020
    Co-Authors: Yiming Li
    Abstract:

    Tooth discoloration may be caused by intrinsic or extrinsic stains or a combination of both. There are 2 major approaches to removing the stains, including the chemical mechanism using peroxides for tooth bleaching and the mechanical mechanism using abrasives in prophylactic pastes and dentifrices to remove stains, resulting in a whitening effect. Attempts have also been made to add a low concentration of peroxides to dentifrices to enhance their abrasive cleaning to remove tooth stains. This article provides a review of both in vitro and clinical studies on stain removal and whitening effect of dentifrices containing sodium bicarbonate (baking soda). In recent years, whitening dentifrices have become popular because of little additional effort for use, ease of availability, low cost, and accumulated evidence of clinical efficacy and safety in the literature. Advances in research and technology have led to innovative formulations of dentifrices using baking soda as the sole abrasive or a component of an abrasive system. Baking soda is biologically compatible with acid-buffering capacities, antibacterial at high concentrations, and has a relatively lower Abrasivity. The evidence available in the literature indicates that baking soda-based dentifrices are effective and safe for tooth stain removal and consequently whitening. A number of clinical studies have also shown that baking soda-based dentifrices are more effective in stain removal and whitening than some non-baking soda-containing dentifrices with a higher Abrasivity. So far, research efforts have mainly focused on stain removal and tooth-whitening efficacy and clinical safety of baking soda dentifrices used with manual toothbrushes, with only a few studies investigating their effects using powered toothbrushes, for which further research is encouraged. As part of a daily oral hygiene practice, baking soda-based dentifrice is a desirable, alternative or additional measure for tooth stain removal and whitening. Copyright © 2017 American Dental Association. Published by Elsevier Inc. All rights reserved.

  • stain removal and whitening by baking soda dentifrice a review of literature
    Journal of the American Dental Association, 2017
    Co-Authors: Yiming Li
    Abstract:

    Abstract Background Tooth discoloration may be caused by intrinsic or extrinsic stains or a combination of both. There are 2 major approaches to removing the stains, including the chemical mechanism using peroxides for tooth bleaching and the mechanical mechanism using abrasives in prophylactic pastes and dentifrices to remove stains, resulting in a whitening effect. Attempts have also been made to add a low concentration of peroxides to dentifrices to enhance their abrasive cleaning to remove tooth stains. Types of Studies Reviewed This article provides a review of both in vitro and clinical studies on stain removal and whitening effect of dentifrices containing sodium bicarbonate (baking soda). In recent years, whitening dentifrices have become popular because of little additional effort for use, ease of availability, low cost, and accumulated evidence of clinical efficacy and safety in the literature. Advances in research and technology have led to innovative formulations of dentifrices using baking soda as the sole abrasive or a component of an abrasive system. Baking soda is biologically compatible with acid-buffering capacities, antibacterial at high concentrations, and has a relatively lower Abrasivity. Conclusions The evidence available in the literature indicates that baking soda–based dentifrices are effective and safe for tooth stain removal and consequently whitening. A number of clinical studies have also shown that baking soda–based dentifrices are more effective in stain removal and whitening than some non–baking soda—containing dentifrices with a higher Abrasivity. So far, research efforts have mainly focused on stain removal and tooth-whitening efficacy and clinical safety of baking soda dentifrices used with manual toothbrushes, with only a few studies investigating their effects using powered toothbrushes, for which further research is encouraged. Practical Implications As part of a daily oral hygiene practice, baking soda–based dentifrice is a desirable, alternative or additional measure for tooth stain removal and whitening.

Anderson T Hara - One of the best experts on this subject based on the ideXlab platform.

  • baking soda as an abrasive in toothpastes mechanism of action and safety and effectiveness considerations
    Journal of the American Dental Association, 2017
    Co-Authors: Anderson T Hara, Cecilia Pedroso Turssi
    Abstract:

    Abstract Background Toothpastes can be formulated with different abrasive systems, depending on their intended clinical application. This formulation potentially affects their effectiveness and safety and, therefore, requires proper understanding. In this article, the authors focused on abrasive aspects of toothpastes containing sodium bicarbonate (baking soda), which have gained considerable attention because of their low Abrasivity and good compatibility, while providing clinical effectiveness (further detailed in the other articles of this special issue). The authors first appraised the role of toothpaste Abrasivity on tooth wear, exploring some underlying processes and the existing methods to determine toothpaste Abrasivity. Types of Studies Reviewed The authors reviewed the available data on the Abrasivity of toothpastes containing baking soda and reported a summary of findings highlighting the clinical implications. Conclusions On the basis of the collected evidence, baking soda has an intrinsic low-abrasive nature because of its comparatively lower hardness in relation to enamel and dentin. Baking soda toothpastes also may contain other ingredients, which can increase their stain removal effectiveness and, consequently, Abrasivity. Practical Implications Even those formulations have Abrasivity well within the safety limit regulatory agencies have established and, therefore, can be considered safe.

  • dentifrice fluoride and Abrasivity interplay on artificial caries lesions
    Caries Research, 2014
    Co-Authors: Hani M Nassar, Frank Lippert, George J Eckert, Anderson T Hara
    Abstract:

    Incipient caries lesions on smooth surfaces may be subjected to toothbrushing, potentially leading to remineralization and/or abrasive wear. The interplay of dentifrice Abrasivity and fluoride on this process is largely unknown and was investigated on three artificially created lesions with different mineral content/distribution. 120 bovine enamel specimens were randomly allocated to 12 groups (n = 10), resulting from the association of (1) lesion type [methylcellulose acid gel (MeC); carboxymethylcellulose solution (CMC); hydroxyethylcellulose gel (HEC)], (2) slurry abrasive level [low (REA 4/ RDA 69); high (REA 7/RDA 208)], and (3) fluoride concentration [0/275 ppm (14.5 mM) F as NaF]. After lesion creation, specimens were brushed in an automated brushing machine with the test slurries (50 strokes 2×/day). Specimens were kept in artificial saliva in between brushings and overnight. Enamel surface loss (SL) was determined by optical profilometry after lesion creation, 1, 3 and 5 days. Two enamel sections (from baseline and post-brushing areas) were obtained and analyzed microradiographically. Data were analyzed by analysis of variance and Tukey's tests (α = 5%). Brushing with high-abrasive slurry caused more SL than brushing with low-abrasive slurry. For MeC and CMC lesions, fluoride had a protective effect on SL from day 3 on. Furthermore, for MeC and CMC, there was a significant mineral gain in the remaining lesions except when brushed with high-abrasive slurries and 0 ppm F. For HEC, a significant mineral gain took place when low-abrasive slurry was used with fluoride. The tested lesions responded differently to the toothbrushing procedures. Both slurry fluoride content and Abrasivity directly impacted SL and mineral gain of enamel caries lesions.

  • comparison between radiotracer and surface profile methods for the determination of dentifrice Abrasivity
    Wear, 2013
    Co-Authors: Alaa H A Sabrah, Frank Lippert, Adam B Kelly, Anderson T Hara
    Abstract:

    Abstract This study compared the traditional radiotracer method (Rt) for determination of dentifrice Abrasivity to the recently introduced surface profile (Sp) method (ISO 11609). Specimens from human root dentin were prepared for each method and randomly assigned to 8 dentifrice/abrasive groups (n=8), of wide Abrasivity range. Aqueous dentifrice slurries or abrasive suspensions were used to brush specimens in a toothbrushing machine. Two independent studies (Rt, Sp) were carried out. For Rt, the specimen preparation, study design, analysis and calculation of the dentifrice abrasive level (RDA) followed the ISO 11609/Annex-A guidelines. Similarly for Sp, the ISO 11609/Annex-B recommendations were followed, except by the number of brushing strokes, which was pre-determined to be 2000 strokes. RDA data were analyzed using ANOVA and Tukey tests (α=0.05). The correlation between methods was also investigated. Overall, higher variation and RDA values were observed for Sp compared to Rt. While good correlation was found between methods (R2=0.841), group ranking was dissimilar and better statistical differentiation among groups was observed in Rt. The Rt method showed to be a more standardized and robust method compared to Sp for the determination of RDA values of dentifrices/abrasives. Sp needs further development before being considered as an equivalent method to Rt.

  • Abrasivity testing of dentifrices challenges and current state of the art
    Monographs in oral science, 2013
    Co-Authors: Carlos Gonzalezcabezas, Anderson T Hara, John J Hefferren, Frank Lippert
    Abstract:

    Abrasivity potential of dentifrices is assessed mostly in vitro due to practical, scientific, and ethical reasons. The two most used evaluation methods are based on the measurement of radioactive dentin release or dentin surface profile changes, after simulation of toothbrushing with dentifrices. The radiotracer method known as radioactive or relative dentin Abrasivity (RDA) was developed decades ago and is the most frequently used today (the ‘gold standard' for many). The RDA is a reasonably robust method considered a useful tool for the determination of the relative abrasive level of dentifrices and abrasive powders. Studying the level of Abrasivity of dentifrices under laboratory conditions is important to develop new formulations, to evaluate quality control of production, and to obtain a rough estimate of its potential clinical Abrasivity. However, it is inappropriate to use RDA values alone to determine clinical safety when considering that dental wear is multifactorial and in vitro dentifrice Abrasivity level is only one of the variables potentially affecting this outcome. It is important to remember that individuals present significant behavioral differences when brushing that could dramatically affect the potential of abrasion of a particular dentifrice. RDA values should be just one of the multiple variables being taken into consideration by professionals when providing recommendations to prevent dental wear.

  • interplay between fluoride and Abrasivity of dentifrices on dental erosion abrasion
    Journal of Dentistry, 2009
    Co-Authors: Anderson T Hara, Jonathan E. Creeth, Carlos Gonzalezcabezas, Madhu Parmar, George J Eckert, Domenick T Zero
    Abstract:

    Abstract Objectives Eroded teeth are more susceptible to toothbrushing wear than sound teeth. We tested the hypothesis that fluoride and Abrasivity of dentifrices can interact, modulating the development of erosive–abrasive lesions. Methods Human enamel and root dentin specimens were submitted to cycles of demineralization, remineralization and toothbrushing using six dentifrices formulated with three different Abrasivity levels: low (L), medium (M) and high (H); with (+F) and without (−F) fluoride. Surface loss was quantified by optical profilometry and compared among groups (α = 0.05). Results In dentin, it was ranked: L  Conclusions Both fluoride and Abrasivity were important modulators of enamel surface loss, while Abrasivity had a higher impact than fluoride on dentin.

Jeffery L Milleman - One of the best experts on this subject based on the ideXlab platform.

  • a randomized clinical trial to evaluate the stain removal efficacy of a sodium phytate dentifrice formulation
    Journal of Esthetic and Restorative Dentistry, 2018
    Co-Authors: Kimberly R Milleman, Jonathan E. Creeth, Gary R. Burnett, Jeffery L Milleman
    Abstract:

    OBJECTIVES: Phytate is an organic, cyclic polyphosphate analogous to linear condensed polyphosphates used as stain removal agents. This study investigated stain removal efficacy of an experimental sodium phytate-containing dentifrice compared to a reference dentifrice. METHODS: An experimental, moderate Abrasivity (relative dentine Abrasivity [RDA] ∼130) antisensitivity fluoride dentifrice containing sodium phytate (0.85% w/w as the hexasodium salt) (n = 111) was compared to a reference, marketed, low-Abrasivity (RDA ∼ 43), anti-sensitivity fluoride dentifrice (n = 113), both containing 1150 ppm fluoride as sodium fluoride. Primary efficacy variables were between-treatment differences in extrinsic dental stain of anterior teeth after 6 and 12 weeks' twice-daily use, using Lobene stain index (MacPherson modification, MLSI) mean area (A) and intensity (I) scores. Comparisons included whole-tooth and hard-to-reach areas (gingival, interproximal, body of lingual). RESULTS: At both 6- and 12-week timepoints, MLSI (A × I) scores for total area and hard-to-reach areas for the experimental dentifrice were statistically significantly lower than baseline (P < .0001 for all). This was demonstrated for the reference dentifrice at 6 weeks only, for total, interproximal (P < .0001 for both), and body of lingual (P = .0395) scores. Compared with the reference, the experimental dentifrice had statistically significantly lower MLSI scores at both 6 and 12 weeks for all outcome variables including both total MLSI (A × I) and hard-to reach areas (P < .0001 in all cases). Products were generally well-tolerated. CONCLUSIONS: Differences between treatments were considered clinically differentiable. Sodium phytate may therefore be a suitable additive ingredient to improve tooth stain control performance within an otherwise conventional dentifrice formulation. CLINICAL SIGNIFICANCE: Following 6 and 12 weeks brushing, clinically differentiable differences were shown in stain index scores with an experimental dentifrice containing sodium phytate compared to a reference dentifrice without sodium phytate. Sodium phytate may therefore be a suitable additive ingredient to improve tooth stain control performance within an otherwise conventional dentifrice formulation.

  • A randomized clinical trial to evaluate the stain removal efficacy of a sodium phytate dentifrice formulation.
    Journal of Esthetic and Restorative Dentistry, 2018
    Co-Authors: Kimberly R Milleman, Jonathan E. Creeth, Gary R. Burnett, Jeffery L Milleman
    Abstract:

    OBJECTIVES: Phytate is an organic, cyclic polyphosphate analogous to linear condensed polyphosphates used as stain removal agents. This study investigated stain removal efficacy of an experimental sodium phytate-containing dentifrice compared to a reference dentifrice. METHODS: An experimental, moderate Abrasivity (relative dentine Abrasivity [RDA] ∼130) antisensitivity fluoride dentifrice containing sodium phytate (0.85% w/w as the hexasodium salt) (n = 111) was compared to a reference, marketed, low-Abrasivity (RDA ∼ 43), anti-sensitivity fluoride dentifrice (n = 113), both containing 1150 ppm fluoride as sodium fluoride. Primary efficacy variables were between-treatment differences in extrinsic dental stain of anterior teeth after 6 and 12 weeks' twice-daily use, using Lobene stain index (MacPherson modification, MLSI) mean area (A) and intensity (I) scores. Comparisons included whole-tooth and hard-to-reach areas (gingival, interproximal, body of lingual). RESULTS: At both 6- and 12-week timepoints, MLSI (A × I) scores for total area and hard-to-reach areas for the experimental dentifrice were statistically significantly lower than baseline (P 

  • a randomized clinical study to evaluate the effect of an ultra low Abrasivity dentifrice on extrinsic dental stain
    American Journal of Dentistry, 2017
    Co-Authors: Sarah Young, Jeffery L Milleman, Stephen Mason, Kimberly R Milleman
    Abstract:

    PURPOSE: To investigate the stain-removal efficacy of an experimental ultra-low Abrasivity anti-sensitivity dentifrice containing sodium tripolyphosphate (STP) and a cocamidopropyl betaine/sodium methyl cocoyl taurate detergent system. METHODS: This was a single-center, examiner-blind, randomized, parallel-group study. Extrinsic dental stain was assessed on the facial surfaces of the six maxillary and six mandibular anterior teeth and the lingual surfaces of the six mandibular anterior teeth using the Macpherson modification of the Lobene Stain Index (MLSI). Treatments were: ultra-low Abrasivity dentifrice [5% w/w KNO3, 5% w/w STP, 1,100 ppm fluoride as sodium fluoride; relative dentin Abrasivity (RDA) ~10; n=54]; moderate Abrasivity fluoride dentifrice (1,100 ppm fluoride as sodium monofluorophosphate; RDA ~68; n= 57); higher Abrasivity daily-use whitening dentifrice (1,100 ppm fluoride as sodium fluoride; RDA~137; n= 57). Subjects brushed for 1 minute, twice daily, for 8 weeks. RESULTS: Mean total MLSI [ Area × Intensity (A×I) ] change from baseline score at Weeks 4 and 8 was significant (P< 0.0001) for all groups. At Week 8, for the ultra-low Abrasivity dentifrice versus the moderate and higher Abrasivity dentifrices, mean total MLSI (A×I) scores (P< 0.0001), along with MLSI endpoints in facial, lingual, and interproximal regions (P= 0.0035 to P< 0.0001), favored the ultra-low Abrasivity dentifrice. Dentifrices were generally well-tolerated. The ultra-low Abrasivity dentifrice containing 5% STP reduced extrinsic dental stain more effectively than moderate or higher Abrasivity dentifrices. CLINICAL SIGNIFICANCE: The ultra-low Abrasivity, anti-sensitivity dentifrice containing 5% STP reduced extrinsic dental stain more effectively than moderate or higher Abrasivity dentifrices, and is thus suitable for patients with sensitive teeth who wish to control extrinsic dental stain.

  • randomized controlled trial to explore the effect of experimental low Abrasivity dentifrices on enamel gloss and smoothness and the build up of extrinsic tooth stain
    The Journal of clinical dentistry, 2017
    Co-Authors: Kimberly R Milleman, Jeffery L Milleman, Sarah Young, Charles R Parkinson
    Abstract:

    OBJECTIVES: To evaluate and compare examiner-assessed changes in enamel gloss, extrinsic dental stain, and surface smoothness following one, two, four, and eight weeks of twice-daily use of an experimental low Abrasivity desensitizing dentifrice (relative dentin Abrasivity [RDA] ~40) containing 5% sodium tripolyphosphate (STP) chemical cleaning agent and 1% aluminum trioxide abrasive. This was compared with an ultra-low Abrasivity dentifrice (5% STP only; RDA ~13), a moderate Abrasivity fluoride dentifrice (RDA ~80), and a higher Abrasivity marketed whitening dentifrice (RDA ~142). METHODS: This was a single-center, examiner-blind, randomized, controlled, parallel group study in healthy adults stratified by gloss score and age. Following a washout period with a conventional silica abrasive dentifrice, subjects received a dental scale and polish and were randomized to treatment. Subjects brushed their teeth for two minutes, twice daily, with their assigned dentifrice. Enamel gloss was assessed visually by comparing the facial surfaces of the maxillary incisors to the Sturzenberger gloss standards. Extrinsic dental stain was measured on the 12 anterior teeth (facial and lingual) using the Macpherson modification of the Lobene Stain Index (MLSI). Tooth smoothness was assessed using scanning electron microscope (SEM) analysis of a silicone impression of the central incisors. RESULTS: Of 120 screened subjects, 95 were randomized to the study. Subjects using the low Abrasivity aluminum trioxide/STP dentifrice demonstrated statistically significant (p < 0.05) and increasing improvements in surface gloss over baseline at all time points, with a significant treatment effect compared to all other study dentifrices from Week 2 (p < 0.05). With respect to dental stain, the low Abrasivity dentifrice group had the lowest stain score at each post-treatment time point and demonstrated statistically significantly less stain compared to all study dentifrices at Weeks 2 (p < 0.05) and 8 (p < 0.01). For tooth smoothness, at Week 8, statistically significant increases in surface smoothness were observed for most treatment groups compared to baseline (p < 0.05), except for the moderate Abrasivity dentifrice. CONCLUSIONS: This study shows the benefit of a low Abrasivity dentifrice containing STP and aluminum trioxide in reducing stain build-up and increasing tooth gloss compared to a non-alumina ultra-low Abrasivity STP-containing dentifrice, and moderate and high Abrasivity dentifrices, over an eight-week period.

  • a randomized clinical study investigating the stain removal potential of two experimental dentifrices
    The Journal of clinical dentistry, 2015
    Co-Authors: Sarah Young, Jeffery L Milleman, Claire Hall, Charles R Parkinson, Nan Wang, Kimberly R Milleman
    Abstract:

    OBJECTIVE: To evaluate the ability of two experimental desensitizing dentifrices, both containing a chemical cleaning agent, one with ultra-low Abrasivity and one with low Abrasivity, a standard fluoride dentifrice, and a daily-use whitening dentifrice to remove extrinsic tooth stain. METHODS: This was a single-center, examiner-blind, randomized, controlled, four-treatment, parallel-group study in healthy adults. Extrinsic stain was evaluated using the Macpherson modification of the Lobene Stain Index (MLSI). At baseline, eligible subjects with a total MLSI (area x intensity [A x I]) score of 15 for the facial surfaces of the 12 anterior teeth were stratified (based on total MLSI [A x I] score [< 45 = low; ≥ 45 = high] and smoking status) and randomized to treatment with one of four dentifrices: an experimental ultra-low Abrasivity desensitizing dentifrice (relative dentin abrasion [RDA] -12); an experimental low Abrasivity desensitizing dentifrice (RDA -40); a standard fluoride dentifrice with moderate Abrasivity (RDA -80); and a whitening dentifrice with higher Abrasivity (RDA -142). Both desensitizing dentifrices contained 5% potassium nitrate and 5% sodium tripolyphosphate (a chemical cleaning agent). Treatment effects were evaluated after four and eight weeks of twice-daily brushing. RESULTS: In total, 142 subjects were randomized and 133 subjects completed the study. All study dentifrices demonstrated statistically significant reductions in extrinsic tooth stain from baseline after four and eight weeks of twice-daily use (p < 0.01). There were no statistically significant between-treatment differences for the primary variable (mean MLSI [A x I] score across all assessed sites) at four or eight weeks, and no notable trends were observed. CONCLUSION: All study dentifrices reduced extrinsic tooth stain. The experimental ultra-low and low Abrasivity desensitizing dentifrices containing 5% sodium tripolyphosphate performed similarly to both a moderate Abrasivity standard fluoride dentifrice and a higher Abrasivity whitening dentifrice.

Kimberly R Milleman - One of the best experts on this subject based on the ideXlab platform.

  • a randomized clinical trial to evaluate the stain removal efficacy of a sodium phytate dentifrice formulation
    Journal of Esthetic and Restorative Dentistry, 2018
    Co-Authors: Kimberly R Milleman, Jonathan E. Creeth, Gary R. Burnett, Jeffery L Milleman
    Abstract:

    OBJECTIVES: Phytate is an organic, cyclic polyphosphate analogous to linear condensed polyphosphates used as stain removal agents. This study investigated stain removal efficacy of an experimental sodium phytate-containing dentifrice compared to a reference dentifrice. METHODS: An experimental, moderate Abrasivity (relative dentine Abrasivity [RDA] ∼130) antisensitivity fluoride dentifrice containing sodium phytate (0.85% w/w as the hexasodium salt) (n = 111) was compared to a reference, marketed, low-Abrasivity (RDA ∼ 43), anti-sensitivity fluoride dentifrice (n = 113), both containing 1150 ppm fluoride as sodium fluoride. Primary efficacy variables were between-treatment differences in extrinsic dental stain of anterior teeth after 6 and 12 weeks' twice-daily use, using Lobene stain index (MacPherson modification, MLSI) mean area (A) and intensity (I) scores. Comparisons included whole-tooth and hard-to-reach areas (gingival, interproximal, body of lingual). RESULTS: At both 6- and 12-week timepoints, MLSI (A × I) scores for total area and hard-to-reach areas for the experimental dentifrice were statistically significantly lower than baseline (P < .0001 for all). This was demonstrated for the reference dentifrice at 6 weeks only, for total, interproximal (P < .0001 for both), and body of lingual (P = .0395) scores. Compared with the reference, the experimental dentifrice had statistically significantly lower MLSI scores at both 6 and 12 weeks for all outcome variables including both total MLSI (A × I) and hard-to reach areas (P < .0001 in all cases). Products were generally well-tolerated. CONCLUSIONS: Differences between treatments were considered clinically differentiable. Sodium phytate may therefore be a suitable additive ingredient to improve tooth stain control performance within an otherwise conventional dentifrice formulation. CLINICAL SIGNIFICANCE: Following 6 and 12 weeks brushing, clinically differentiable differences were shown in stain index scores with an experimental dentifrice containing sodium phytate compared to a reference dentifrice without sodium phytate. Sodium phytate may therefore be a suitable additive ingredient to improve tooth stain control performance within an otherwise conventional dentifrice formulation.

  • A randomized clinical trial to evaluate the stain removal efficacy of a sodium phytate dentifrice formulation.
    Journal of Esthetic and Restorative Dentistry, 2018
    Co-Authors: Kimberly R Milleman, Jonathan E. Creeth, Gary R. Burnett, Jeffery L Milleman
    Abstract:

    OBJECTIVES: Phytate is an organic, cyclic polyphosphate analogous to linear condensed polyphosphates used as stain removal agents. This study investigated stain removal efficacy of an experimental sodium phytate-containing dentifrice compared to a reference dentifrice. METHODS: An experimental, moderate Abrasivity (relative dentine Abrasivity [RDA] ∼130) antisensitivity fluoride dentifrice containing sodium phytate (0.85% w/w as the hexasodium salt) (n = 111) was compared to a reference, marketed, low-Abrasivity (RDA ∼ 43), anti-sensitivity fluoride dentifrice (n = 113), both containing 1150 ppm fluoride as sodium fluoride. Primary efficacy variables were between-treatment differences in extrinsic dental stain of anterior teeth after 6 and 12 weeks' twice-daily use, using Lobene stain index (MacPherson modification, MLSI) mean area (A) and intensity (I) scores. Comparisons included whole-tooth and hard-to-reach areas (gingival, interproximal, body of lingual). RESULTS: At both 6- and 12-week timepoints, MLSI (A × I) scores for total area and hard-to-reach areas for the experimental dentifrice were statistically significantly lower than baseline (P 

  • a randomized clinical study to evaluate the effect of an ultra low Abrasivity dentifrice on extrinsic dental stain
    American Journal of Dentistry, 2017
    Co-Authors: Sarah Young, Jeffery L Milleman, Stephen Mason, Kimberly R Milleman
    Abstract:

    PURPOSE: To investigate the stain-removal efficacy of an experimental ultra-low Abrasivity anti-sensitivity dentifrice containing sodium tripolyphosphate (STP) and a cocamidopropyl betaine/sodium methyl cocoyl taurate detergent system. METHODS: This was a single-center, examiner-blind, randomized, parallel-group study. Extrinsic dental stain was assessed on the facial surfaces of the six maxillary and six mandibular anterior teeth and the lingual surfaces of the six mandibular anterior teeth using the Macpherson modification of the Lobene Stain Index (MLSI). Treatments were: ultra-low Abrasivity dentifrice [5% w/w KNO3, 5% w/w STP, 1,100 ppm fluoride as sodium fluoride; relative dentin Abrasivity (RDA) ~10; n=54]; moderate Abrasivity fluoride dentifrice (1,100 ppm fluoride as sodium monofluorophosphate; RDA ~68; n= 57); higher Abrasivity daily-use whitening dentifrice (1,100 ppm fluoride as sodium fluoride; RDA~137; n= 57). Subjects brushed for 1 minute, twice daily, for 8 weeks. RESULTS: Mean total MLSI [ Area × Intensity (A×I) ] change from baseline score at Weeks 4 and 8 was significant (P< 0.0001) for all groups. At Week 8, for the ultra-low Abrasivity dentifrice versus the moderate and higher Abrasivity dentifrices, mean total MLSI (A×I) scores (P< 0.0001), along with MLSI endpoints in facial, lingual, and interproximal regions (P= 0.0035 to P< 0.0001), favored the ultra-low Abrasivity dentifrice. Dentifrices were generally well-tolerated. The ultra-low Abrasivity dentifrice containing 5% STP reduced extrinsic dental stain more effectively than moderate or higher Abrasivity dentifrices. CLINICAL SIGNIFICANCE: The ultra-low Abrasivity, anti-sensitivity dentifrice containing 5% STP reduced extrinsic dental stain more effectively than moderate or higher Abrasivity dentifrices, and is thus suitable for patients with sensitive teeth who wish to control extrinsic dental stain.

  • randomized controlled trial to explore the effect of experimental low Abrasivity dentifrices on enamel gloss and smoothness and the build up of extrinsic tooth stain
    The Journal of clinical dentistry, 2017
    Co-Authors: Kimberly R Milleman, Jeffery L Milleman, Sarah Young, Charles R Parkinson
    Abstract:

    OBJECTIVES: To evaluate and compare examiner-assessed changes in enamel gloss, extrinsic dental stain, and surface smoothness following one, two, four, and eight weeks of twice-daily use of an experimental low Abrasivity desensitizing dentifrice (relative dentin Abrasivity [RDA] ~40) containing 5% sodium tripolyphosphate (STP) chemical cleaning agent and 1% aluminum trioxide abrasive. This was compared with an ultra-low Abrasivity dentifrice (5% STP only; RDA ~13), a moderate Abrasivity fluoride dentifrice (RDA ~80), and a higher Abrasivity marketed whitening dentifrice (RDA ~142). METHODS: This was a single-center, examiner-blind, randomized, controlled, parallel group study in healthy adults stratified by gloss score and age. Following a washout period with a conventional silica abrasive dentifrice, subjects received a dental scale and polish and were randomized to treatment. Subjects brushed their teeth for two minutes, twice daily, with their assigned dentifrice. Enamel gloss was assessed visually by comparing the facial surfaces of the maxillary incisors to the Sturzenberger gloss standards. Extrinsic dental stain was measured on the 12 anterior teeth (facial and lingual) using the Macpherson modification of the Lobene Stain Index (MLSI). Tooth smoothness was assessed using scanning electron microscope (SEM) analysis of a silicone impression of the central incisors. RESULTS: Of 120 screened subjects, 95 were randomized to the study. Subjects using the low Abrasivity aluminum trioxide/STP dentifrice demonstrated statistically significant (p < 0.05) and increasing improvements in surface gloss over baseline at all time points, with a significant treatment effect compared to all other study dentifrices from Week 2 (p < 0.05). With respect to dental stain, the low Abrasivity dentifrice group had the lowest stain score at each post-treatment time point and demonstrated statistically significantly less stain compared to all study dentifrices at Weeks 2 (p < 0.05) and 8 (p < 0.01). For tooth smoothness, at Week 8, statistically significant increases in surface smoothness were observed for most treatment groups compared to baseline (p < 0.05), except for the moderate Abrasivity dentifrice. CONCLUSIONS: This study shows the benefit of a low Abrasivity dentifrice containing STP and aluminum trioxide in reducing stain build-up and increasing tooth gloss compared to a non-alumina ultra-low Abrasivity STP-containing dentifrice, and moderate and high Abrasivity dentifrices, over an eight-week period.

  • a randomized clinical study investigating the stain removal potential of two experimental dentifrices
    The Journal of clinical dentistry, 2015
    Co-Authors: Sarah Young, Jeffery L Milleman, Claire Hall, Charles R Parkinson, Nan Wang, Kimberly R Milleman
    Abstract:

    OBJECTIVE: To evaluate the ability of two experimental desensitizing dentifrices, both containing a chemical cleaning agent, one with ultra-low Abrasivity and one with low Abrasivity, a standard fluoride dentifrice, and a daily-use whitening dentifrice to remove extrinsic tooth stain. METHODS: This was a single-center, examiner-blind, randomized, controlled, four-treatment, parallel-group study in healthy adults. Extrinsic stain was evaluated using the Macpherson modification of the Lobene Stain Index (MLSI). At baseline, eligible subjects with a total MLSI (area x intensity [A x I]) score of 15 for the facial surfaces of the 12 anterior teeth were stratified (based on total MLSI [A x I] score [< 45 = low; ≥ 45 = high] and smoking status) and randomized to treatment with one of four dentifrices: an experimental ultra-low Abrasivity desensitizing dentifrice (relative dentin abrasion [RDA] -12); an experimental low Abrasivity desensitizing dentifrice (RDA -40); a standard fluoride dentifrice with moderate Abrasivity (RDA -80); and a whitening dentifrice with higher Abrasivity (RDA -142). Both desensitizing dentifrices contained 5% potassium nitrate and 5% sodium tripolyphosphate (a chemical cleaning agent). Treatment effects were evaluated after four and eight weeks of twice-daily brushing. RESULTS: In total, 142 subjects were randomized and 133 subjects completed the study. All study dentifrices demonstrated statistically significant reductions in extrinsic tooth stain from baseline after four and eight weeks of twice-daily use (p < 0.01). There were no statistically significant between-treatment differences for the primary variable (mean MLSI [A x I] score across all assessed sites) at four or eight weeks, and no notable trends were observed. CONCLUSION: All study dentifrices reduced extrinsic tooth stain. The experimental ultra-low and low Abrasivity desensitizing dentifrices containing 5% sodium tripolyphosphate performed similarly to both a moderate Abrasivity standard fluoride dentifrice and a higher Abrasivity whitening dentifrice.