Evaluation of toothpastes and of the variables associated with the choice of a product.

ABSTRACT

Background: Some 200 toothpastes are available on the Canadian market, and the abrasiveness of most of them is unknown. The most recent Quebec abrasiveness scale, dating from 1994 and evaluating only 60 products, is both incomplete and out of date. Moreover, the large number of manufacturing methods complicates product comparison in terms of, for example, abrasiveness, pH, and water-insoluble material. Method: In 2004 and 2005, an interdisciplinary team (dental hygiene, physics, chemistry, and biology) developed two new protocols for analyzing toothpastes. A machine simulated brushing on blocks of polymethylmethacrylate, which has similar properties to human dentin. The equipment included a vacuum system, vortex, magnetic stirrer, desiccator, scale, pH meter, and stopwatch. A solution of 25 g of toothpaste and 25 g of distilled water was applied according to the equation F = 150 g x 120 mvts/4 hours. Results: As indicated by the manufacturers, most toothpastes reduce certain problems: caries (76%), staining (42%), tartar (26%), gingivitis (21%), and hypersensitivity (12%). One percent are multicare toothpastes and 55 products bear the Canadian Dental Association (CDA) seal. There are significant differences among toothpastes: abrasiveness ranges from 0 to 6; pH varies from 3 to 10, and flow from 0.1 to 10 ml in 10 seconds; foaming may differ by a factor of 3 from one brand to another. Conclusion: The choice of toothpaste has a major impact on the reduction of certain dental problems and the maintenance of oral hygiene.

Key words: toothpaste, pH, abrasiveness

RESUME

Probleme. Le marche canadien compte environ 200 dentifrices, dont l'abrasivite est en grande partie inconnue. Puisque la derniere echelle quebecoise sur l'abrasivite n'evaluait que 60 produits et remonte a 1994, elle est aussi perimee qu'incomplete. De plus, la multiplicite des methodes de fabrication complique la comparaison des produits, par exemple quant a l'abrasivite, au pH et aux matieres insolubles. Methode. En 2004 et 2005, une equipe interdisciplinaire (hygiene dentaire, physique, chimie et biologie) a etabli deux nouveaux protocoles d'analyse des dentifrices. Une machine simulait le brossage sur des blocs de polymethylmethacrylate, matiere semblable a la dentine humaine. L'equipement incluait un systeme de vacuum, un vortex, un agitateur magnetique, un dessiccateur, une balance, un pH-metre et un chronometre. Une solution de 25 g de dentifrice et de 25 g d'eau distillee etait appliquee selon l'equation F = 150 g x 120 mvts/4 heures. Resultats. Selon les indications des manufacturiers, la plupart des dentifrices reduisent certains problemes: la carie (76 %), les taches (42 %), le tartre (26 %), la gingivite (21 %) et l'hypersensibilite (12 %); 1 % des dentifrices sont multisoins et 55 produits portent le sceau de l'ADC. Il existe d'importantes differences entre les dentifrices: l'abrasivite varie de 0 a 6, le pH de 3 a 10 et l'ecoulement de 0,1 a 10 ml en 10 secondes; la mousse peut tripler d'une marque a l'autre. Conclusion. Le choix d'un dentifrice influence de facon importante la reduction de certains problemes buccodentaires et le maintien de la sante dentaire.

Mots cles: dentifrice, pH, abrasivite

1. INTRODUCTION

IN 2005, THERE IS A REAL LACK OF INFORMATION CONcerning the abrasiveness of toothpastes. Dental care professionals have gaps in their knowledge, given that data available on abrasiveness have not been updated since 1994 when the last study by Desautels and Labreche of Universite de Montreal appeared. (1) Some manufacturers provide their own abrasiveness scale but their equipment and methodologies may vary, which makes comparison difficult.

Certain variables have been added to the process as these variables enable verification of practical factors related to brushing. Acidity may favour demineralization, which has already been studied with regard to toothpastes sold in Europe. (2) For example, we know that acid liquids increase the permeability of dentin. (3) In 2004, Josiak et al. (4) published an article on flow, comparing paste and liquid toothpastes. The article concluded that liquid toothpaste released a greater quantity of fluoride on the enamel over different periods of time, which increases the tooth's resistance to caries. On the other hand, toothpastes are composed of numerous water-soluble and water-insoluble ingredients. (5) It is important to consider water-solubility since daily brushing is with water and not oil. (In their study, Desautels and Labreche (1) used an oil mixture to prevent the bicarbonate from dissolving in water.) Since it is currently impossible to separate toothpastes based on their bicarbonate content, there is a risk of methodological bias. The interdisciplinary team solved this problem by including a new test, one for insoluble materials contained in toothpastes. Finally, foaming power is another important factor to consider for users of electric toothbrushes and for people with xerostomia, among others. A toothpaste evaluation kit (6) made it possible to verify this variable.

2. LITERATURE REVIEW

With interdisciplinary work, precision in terminology is required. We relied on the works of Wilkins (7,8) because these have been dental hygiene reference works for decades and in addition were translated from English into French in 1991. The ninth edition, which was published in 2005, covers the same data. Thus, toothpaste is defined as a substance used with a toothbrush or any other applicator to remove, for aesthetic or hygienic reasons, bacterial plaque, materia alba, and accumulated debris on the gums and teeth, and to apply specific preventive or therapeutic agents to the teeth. (7,8) As for the term abrasion, it corresponds to the action of an abrasive product (9) or to the pathological wear of components of the tooth surface because of an abnormal mechanical process. (1) Abrasion may be caused by a combination of several factors, for example, brushing frequency; the stiffness of the bristles; the pressure applied; and the pH, hardness, and abrasiveness of the toothpaste. (10)

With regard to the reference framework, toothpastes can be part of the environment, according to CDHA's process model, (11) which was inspired by Health and Welfare Canada's standards. (12) Forrest and Miller's model (13,14) is also very appropriate because it includes four factors that must be considered: scientific evidence, the customer, the professional, and the environment. All four factors were taken into consideration in this study.

2.1 General composition of toothpastes

The general composition of toothpastes (see table 1) has varied over time and in different countries. Oral hygiene products existed as early as 6,000 years ago, (15) and the Egyptians used a toothpaste whose recipe included iris flowers, among other ingredients. In eighteenth-century England, a paste for teeth and gums was imported from the Orient. (10) In 1991, Wilkins (7,8) studied the general composition of toothpastes.

According to La chimie des produits cosmetiques, (16) toothpaste formulas vary from one manufacturer to another. Thus, Wilkins arrives at slightly different percentages of ingredients. (7,8) The importance of this study is in the general picture it provides, even though it does not conduct a detailed analysis.

2.2 Factors related to abrasiveness

This section presents an overview of the mechanical concepts related to the loss of dental substance. It starts with Newton's equation, which explains force, (17) then examines the acidity of toothpastes, Mohs' particle hardness scale, (18) and the choice of toothpastes from the perspective of customers, manufacturers, and dental care professionals. (19) Forrest and Miller's model (13,14) proves very relevant to the study of toothpastes.

2.2.1 Newton's equation

Newton's equation (18) brings together force, mass, speed, and time, all variables that are relevant in dentistry. The application of excessive force during brushing and the length of brushing time are important factors: excessive force can be harmful and can result, for example, in abrasion of the enamel or root, dentin exposure, gingival abrasion, and recession of the free gingiva. (3)

F = ma, or Force = Mass x Acceleration (or speed and time)

2.2.2 Toothpaste acidity

The idea that pH is related to the abrasiveness of toothpastes may seem surprising in Canada, but in Europe many toothpastes indicate the pH. (2) For example, Elmex includes it in its advertising, which appears in the Swiss dental hygienists' journal. (19) In 1983, Lehne and Winston (10) focused on this variable, which has an impact on abrasion. Traditionally in dentistry, chemical wear corresponds more to erosion. (3) Acidity is relevant to our study because fluoride acts differently if the environment is neutral or acidic. (20) In addition, tooth demineralization can start at a pH of 6.5 for the root and 5.5 for the enamel. (9) According to the results of studies carried out on European toothpastes, (2) some toothpastes have a pH below the critical threshold (5.5). Moreover, acidity affects plaque control, tartar reduction, and the treatment of hypersensitivity. (21) Whitening toothpastes with peroxide tend to be acidic. (22) Bicarbonate of soda, on the other hand, has been used as an antacid for centuries. (9) Tests measuring the acidity of toothpastes are therefore innovative.

2.2.3 Particle hardness

In 1812, Mohs established the hardness of 10 minerals and created a scale that is still used today. This 10-point scale classifies materials from softest (1) to hardest (10):

1 = talc, 2 = gypsum, 3 = calcite, 4 = fluoride, 5 = apatite, 6 = moonstone, 7 = quartz, 8 = topaz, 9 = corundum, 10 = diamond (18)

The hardness of the parts of the tooth and of certain abrasives contained in toothpastes was compared in 1983 by Lehne and Winston in Clinical Preventive Dentistry: (10)

* dentin: 2 to 2.5

* sodium bicarbonate: 2.5

* sodium dihydrate: 2.5

* calcium carbonate: 3

* anhydrous dicalcium phosphate: 3.5

* tooth enamel: 4 to 5

* calcium pyrophosphate: 5

* alumina: 9.25

The practical aspects of these scales are important to improve our understanding of abrasiveness measurements. For example, Desautels and Labreche (1) used four levels in their scale of abrasiveness, which ranges from 0 to 2 or more, where 0 corresponds to "not very abrasive" and 2 or more to "very abrasive." Desautels and Labreche's ceiling level of 2 or more seems logical since it is equal to or greater than the hardness of dentin, a part of the tooth that is often exposed in adults. With a hardness index of 4 to 5, enamel is harder than dentin, which should permit the use of a more abrasive toothpaste if the dentin is not exposed, especially when one considers that the average length of time spent on brushing is about one minute. (5) Fluoride, which is at level 4 on the Mohs scale, is similar to enamel. Moreover, its action depends on its concentration: it can act as an abrasive, (17) antibacterial agent, (20) and anti-cavity treatment. (7,8) A toothpaste that contains alumina is effective at removing stains but it is very likely to damage the tooth surface as alumina is too hard, 9.25 on the Mohs scale.

The next section looks briefly at the various reasons why members of the general public choose particular toothpastes.

2.2.4 Factors related to the choice of a toothpaste

In general, the factors related to the choice of toothpaste vary from one group to another, based on each group's interests. Thus, the general public, manufacturers, and dental care professionals may choose a toothpaste based on cost, active agents, or marketing. Consequently, all these aspects must be taken into consideration. (15,23)

A. The public attaches particular importance to the cost of toothpaste, its appearance and aesthetic qualities--its taste, the foam that it produces, breath and the fresh, clean feeling that it leaves after brushing--and various aspects related to health such as its ability to prevent caries and bleeding gums. People want good-quality products that are quick and easy to use. (15,23)

B. Manufacturers offer the public products that the public finds attractive. For example, one of their strategies is to offer products that are recommended by professionals to prevent, as much as possible, oral and dental problems. (23)

* Marketing in reaction to the competition: To please consumers, the number of products on offer keeps growing. (1) For example, manufacturers launch toothpastes that are designed for dentures or the tongue, that are compatible with homeopathic products, non-foaming for electric toothbrushes, without preservatives, without fluoride, without dyes, without peroxide, without artificial flavours, etc. Recently, new products have been adapted for various health problems such as diabetes (with sweeteners that have no effect on blood sugar), xerostomia (adding salivary enzymes or decreasing foaming agents), or high blood pressure (without bicarbonate of soda or salt).

* The addition of therapeutic agents: The specific action of certain agents makes it possible to reduce oral health problems. For example, enzymes are added to pre-digest milk or to increase saliva, vitamin B or C to promote gum health, and amine or calcium fluorides to strengthen teeth and periodontal bones.

C. Professionals emphasize prevention and health promotion. They attempt to reduce risk factors such as using a very acidic toothpaste on a tooth with caries, or they recommend protective factors such as the use of a toothpaste containing fluoride. (23)

* There are two major toothpaste categories: those with a cosmetic function, which focus on appearance, and those with a therapeutic function, which contain agents that promote oral health. Legislation applies to therapeutic products with an ISBN code.

* Therapeutic toothpastes have existed for some 20 years. The market offers anti-tartar, anti-caries, antibacterial, desensitizing and other products designed to combat xerostomia, bad breath, stains, etc. (9) In exchange for a fee, the Canadian Dental Association (CDA) (24) may grant its seal to a therapeutic product if it complies with certain standards and is subject to a rigorous process including scientific studies.

Current data, although not exhaustive, allow us to formulate the principal question and the objective of this study, which was designed to evaluate the abrasiveness of toothpastes available in 2005. The general aim of the study is to update the data on toothpaste abrasiveness and certain variables associated with toothpastes: the level of insoluble materials, foaming power, viscosity, and pH. It would be possible to expand the literature review further.

3. METHODOLOGY

3.1 Pre-tests

A number of pre-tests allowed us to verify the preparation of blocks of polymethylmethacrylate (PMMA); force, speed, and duration variables; the choice of materials used for the in vitro study; and the dilution of solutions for the abrasiveness, pH, viscosity, and foaming power tests. Vacuum assembly and choice of filters, and dilution with water and toothpaste for the insoluble materials test, were covered by additional procedures.

The design and manufacture of the brushing machine took several months. Desautels and Labreche's (1) old model used five toothpastes in five compartments, whereas the new model has seven compartments. (See figure 1.) This permits two samples apiece of three toothpastes to be tested simultaneously, with the last compartment acting as a control. The seven toothbrush heads are inserted into small compartments designed for that purpose. The Oral-B brush was chosen for two reasons, its soft bristles and its rectangular head. Soft-bristle brushes are recommended for daily brushing, and the rectangular shape was selected because it has the advantage of wearing down the blocks of PMMA uniformly in the centre and at the edges, while presenting a flat surface. Since the handle of the Oral-B 40 is flexible, it was replaced by a rigid metal stem. The blocks of PMMA were placed in a pan divided into seven compartments. The equipment is relatively easy to clean between tests. In addition, a cover was added to reduce evaporation and splashing from particularly liquid toothpastes, among other things. (See figure 2.) A powerful motor made it possible to keep parameters consistent throughout the experiment, which would not have been the case with batteries. The equipment was attached to a large steel plate to avoid vibrations and maintain the precision of the adjustments. Given the sturdiness of the equipment, it will be possible to use it again when repeating the study.

The equation F = ma (17) or F = mv/t allows us to compare the methodology of several studies of toothpastes. For example, Desautels and Labreche (1) conducted their tests over 48 hours with a very low force, whereas Pickles and Joiner (24) completed the brushing in a few seconds but applied a high force (greater than 200 g), which Bowen (5) advises against, whether using manual or electric brushes. The Comite dentifrice opted for a force of 150 g, which is adapted to brushing, and a duration of four hours since certain toothpastes evaporated in five hours despite the cover.

Desautels and Labreche's (1) equation: F = 55 g x 52 mvts for 18 hours; solution made up of two-thirds toothpaste and one-third water

Pickles and Joiner's (25) equation: F = 375 g x 400 mvts for a few seconds, solution made up of 38.5% toothpaste and 61.8% water

ADA (26,27) equation: 150 g x 1500 mvts for a few seconds; solution including radioactive isotopes in 10 g of toothpaste and 50 ml of 5% carboxymethyl cellulose, which results in RDA (radioactive dentin abrasion) or REA (radioactive enamel abrasion)

FXG equation: F = 150 g x 120 mvts for 4 hours; solution made up of 25 g toothpaste and 25 g water

3.2 Protocol

The method was based on Desautels and Labreche's (1) study, which used weight to determine the abrasiveness of the toothpastes when measuring the wear of the PMMA blocks. Their study had the following steps: the PMMA blocks were cleaned with toluene, dried, and placed in the desiccator for 48 hours. They were then accurately weighed on the Mettler scale. Their weight could not exceed 160 g [+ or -] 0.01g. The preparation of the aqueous solution was two-thirds toothpaste and one-third distilled water, except in the case of tooth powders and sodium bicarbonate. The five toothpastes in solution were placed in the five compartments and brushed simultaneously. The force applied was 55 g at a speed of 52 mvts/min. The blocks were then washed, dried, and placed in the desiccator for 48 hours. The brushes were changed after each experiment. The relative abrasion was calculated by establishing the ratio of the weight lost by the specimen over its initial weight x 100. The results for 60 toothpastes were categorized into four abrasion levels: very abrasive (2 and over), abrasive (1.37 to 1.99), moderately abrasive (0.88 to 1.36), and not very abrasive (0 to 0.87). A special section presents "natural" toothpastes (Desautels and Labreche's terminology).

The American Dental Association (26,27) proposes using RDA (radioactive dentin abrasion) and REA (radioactive enamel abrasion) values to verify the abrasiveness of toothpastes. The methodology prescribes the use of a radioactive solution composed of 10 g of calcium pyrophosphate and 50 ml of 5% carboxymethyl cellulose. The number of movements is 1500 brushings on human enamel or dentin. Blocks of PMMA are also used in in vitro studies. A number of manufacturers follow the ADA recommendations and this information is included on the tubes of several European brands. (2,22) The cost of the equipment is very high.

The protocol followed by the Comite dentifrice and summarized below was directed by a doctorate in chemistry. The tube of toothpaste used was new, and only the first portion of the tube was used in the testing. In some cases, the toothpaste varied in terms of colour and oil separation from the toothpaste as a whole. We verified several toothpastes with two identical tubes or with a sample taken from the centre of the tube. In each case, we noticed some variance in the results. Thus toothpastes do not seem to be homogeneous, either from one tube to another or even within a single tube. It would be interesting to find out how toothpastes are manufactured, but that was not the goal of this study. In all cases, the protocol was applied rigorously, and only the first part of the tubes was used. Moreover, the seven brushes were changed before each use.

The protocol for the study of toothpaste abrasiveness and other characteristics was as follows:

 1. Wash the blocks of PMMA and place them in the desiccator for a
    minimum of 48 hours. Weigh the blocks.
 2. Prepare the solution of 50% toothpaste and 50% water (25,000 g
    [+ or -] 0.001 g each). Measure the height of the mixture twice.
    Stir on the magnetic plate for five minutes. Measure the height of
    the foam and compare. Note: The qualitative measurement was done
    with a ruler as we did not have a very accurately graduated 250-ml
    beaker. Measure twice.
 3. Carry out the viscosity test twice by pumping 10 ml into a
    serological pipette and measuring the flow in 10 seconds.
 4. Carry out the pH test twice by standardizing the pH meter and
    immersing the electrode in 3 ml of solution.
 5. Verify the shape of the particles. Take two microscope photographs
    (optional).
 6. Carry out the abrasiveness tests by preparing seven blocks of PMMA.
    Pour 20 ml of solution into two compartments and fill one
    compartment with water (control). Thus, two samples each of three
    toothpastes are tested simultaneously. Insert the new brushes and
    adjust the apparatus and the stopwatch to ensure that the test lasts
    for four hours.
 7. Start and stop the brushing according to uniform parameters of
    speed, weight, and duration.
 8. Take a sample of the toothpaste used. Observe the shape of the
    particles after the tests. Take two microscope photographs
    (optional).
 9. Wash the blocks of PMMA and place them in the desiccator for a
    minimum of 48 hours. Weigh the resin blocks.
10. Remove the brushes and clean the equipment.

The protocol for the insoluble materials test comprised the following steps: place the filter in the desiccator for a minimum of 48 hours, prepare the assembly in a vacuum; mix 2 g [+ or -] 0.001 of toothpaste and 10 g [+ or -] 0.001 of water and stir in the vortex for 3 minutes (same duration as the brushing); transfer to the filter placed in the Buchner funnel. Then add 5 g [+ or -] 0.001 of water and repeat three times, also stirring in the vortex. Filter--which may take from several seconds to 12 hours, with the average time being about 30 minutes--to allow the mixture to flow through completely. Finally, put the filter back in the desiccator and weigh after 48 hours.

The protocols were applied using the equipment described below.

3.3 Equipment

The brushing machine and the toothbrushes without handles were designed and produced at College FXG, and the blocks of PMMA were cut there. Most of the equipment was lent by various departments of the college. The following table (table 2) lists the equipment and notes both the supplier and features.

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]

Finally, the statistical processing was done with Microsoft Excel software, 2003 version. The method used to determine abrasiveness was the same as that used by Desautels and Labreche (1), that is, the ratio of the final weight loss of the block of PMMA over its initial weight x 100. For example, for a 0.842 g block that weighed 0.815 g after the abrasiveness test, the calculation would be as follows:

[[Initial mass of the block of PMMA - Final mass of the block of PMMA]/Initial mass of the block of PMMA] x 100%

In our example:

[[0.842-0.815]/0.842] x 100 = [0.027/0.842] x 100 = 3.2

The abrasiveness is expressed as a percentage, but in practice, one would tend to use the numerical value 3.2 for this toothpaste. The test is done on two different blocks simultaneously. The mean for the two tests is multiplied by 100 and constitutes the final result.

The rate of insoluble materials is determined by multiplying the difference between the final mass of the filter and its initial mass by 100. This test was only done once, since it requires a lot of time during the filtration phase. Although it was generally limited to 30 minutes, it could take more than 12 hours in the case of certain mixtures.

Foaming power is a qualitative measurement. During these tests, the 250-ml beaker contained 25 g of toothpaste and 25 g of distilled water, the initial mixture. Mixing was done on a magnetic plate for five minutes. The final mixture was homogeneous, but its volume was generally greater. The first measurement is the minimum height and the second the maximum height. For example, some toothpastes produce a huge 20-mm bubble. The mean for the two tests was calculated. The difference between the initial mixture and the final mixture provides the measurement of foaming power. Since the beaker was not finely graduated, we used a millimetre ruler and repeat the measurement twice. The mean for the two tests constituted the final result.

The calculation of the flow rate of a toothpaste was done as follows: Mean of the initial volume of 10 ml of solution at time 0 and the flow volume after 10 seconds. The higher the measurement, the faster the mixture flows. For example, the mean of an initial volume of 10 ml and a final volume of 8 ml is 9 ml. The final result is the mean of the two tests.

The pH was calculated by means of a direct reading with a pH-meter, for example, 7.14 and 7.15. The measurement was taken twice and the mean constituted the final result.

In order to determine the active agents, among other things, we noted the ingredients of the toothpastes. We should point out that there are major differences between the ingredients detected and those listed on the packaging. In fact, manufacturers are not required by law to provide a complete list of ingredients. Thus the list came from the packaging or was derived from our actual observations concerning, for example, colour. In a future project, the list of ingredients should be analyzed in more detail.

In general, the data were entered into an Excel spreadsheet for each series of tests. To ensure accurate results, double data entry was done by a third-party committee member.

The descriptive data resulting from a compilation of the tests and including frequencies, means, and percentages, are provided in the results section. In addition, general data were obtained by reading the information provided on the packaging by the manufacturers, such as anti-caries or anti-tartar action. As well, the products were observed directly, for example, concerning colour and flavour, since people may choose a toothpaste based on these criteria. However, information on market trends was not available.

The next section presents partial results for the toothpastes. It should be emphasized that, since the complete results are very lengthy, they will be covered in a second phase of the project that will include, among other things, the production of new teaching tools and a comparative chart.

4. RESULTS

Partial results for approximately 200 products are presented in two major sections: general data and detailed specific data. In general, the first section indicates the manufacturers and the characteristics provided primarily by them, such as colour, flavour, texture, format, and specific action of the toothpastes. The second section with specific data presents some results on abrasiveness, pH, insoluble materials, foaming power and flow, and compares certain dental products. Of the 196 products assessed, 98% are available on the market, and 2% come from home recipes such as the mixture of bicarbonate and peroxide, which is regularly used in gentle periodontal care. For comparative purposes, a gentle prophylaxis product, a whitening product, and a product designed for denture maintenance, as well as cleansing gels for the tongue and Brush-Ups teeth wipes, were also checked. Some American and European toothpastes were tested since they are readily found on the Canadian market.

4.1 General data

4.1.1 Toothpaste manufacturers

Described with the term "other," 51% of manufacturers offer a small number of toothpastes. The major market share belongs to three big multinationals: Colgate-Palmolive (13%), Procter & Gamble (13%) and GlaxoSmithKline (10%). See table 3.

4.1.2 General characteristics of toothpastes

In general, toothpaste is a white, mint-flavoured paste, available in a tube, which protects against caries or whitens the teeth. (See table 4.) The emergence of new trends is becoming evident, such as the arrival on the scene of toothpaste that is orange, that tastes like cinnamon or citrus, that is a liquid or that comes in a vertical pump, as well as toothpastes designed for diabetics.

It should be noted that the manufacturers set out the specific action of each product. Of the products available, 55 toothpastes bear the Canadian Dental Association (CDA) seal. (24) Of these, 45 are approved for caries, 7 for sensitive teeth, and 3 for gingivitis. An Internet search would have provided more information, but this study was limited to the information written on the package or the tube.

4.2 Detailed test results

Since the complete results are very lengthy, we discuss a few examples of products here and will include the detailed tables in the educational tools to be distributed later.

4.2.1 Abrasiveness*

Over one-third of the toothpastes, or 35.7%, proved to be "not very abrasive" (see table 5). Approximately 75% fell below 2 on the scale, which corresponds to the hardness of dentin. Nevertheless, close to 25% are above this threshold. A few toothpastes are above 4, a level at which they could damage enamel.

* Desautels and Labreche (1) and the Comite dentifrice used the same categories, although the Comite's methodology was adapted to take account of the numerous toothpastes on the market in 2005.

4.2.2 pH

Most toothpastes--more than 80%--are neutral or basic. See table 6. The acidic or highly acidic products--15% of the products tested or 30 products--are located below the critical threshold (6) for demineralization.

4.2.3 Insoluble materials

Insoluble materials were obtained using the vacuum assembly. Most of the toothpastes contained either between 30% and 40% insoluble material or less than 10%. (See table 7.) The pH of toothpastes with few insoluble materials and low abrasiveness is generally neutral or acidic. For example, Gel-Kam Fruit and Berry has 0% insoluble materials, 0% abrasiveness, and a pH of 3.6.

4.2.4 Foaming power

Approximately 50% of the toothpastes, or 97 products, do not produce much foam (see table 8). Non-foaming toothpastes are particularly appreciated in cases of dry mouth or when using an electric toothbrush.

4.2.5 Flow rate

In general, the flow rate for toothpastes is moderate, or approximately five drops per second. (See table 9.) The more insoluble materials a toothpaste contains, the more slowly it flows. For example, Sea Fresh, which contains 55.35% insoluble materials, flows at a rate of 0.5 ml in 10 seconds. In this test, water, which flows at a rate of 10 ml in 10 seconds, is the reference substance.

For information purposes only, the graph in figure 3 shows the distribution of insoluble materials based on the four levels on the abrasiveness scale. Additional statistical analyses would provide more detailed information. In general, the more insoluble materials a toothpaste contains, the greater the probability that it will fall into the "very abrasive" category. For example, Healthy Mouth, Tea Tree (abrasiveness of 5.17%) is high, with 55.90% insoluble materials. Children's toothpastes are not very abrasive and contain between 10% and 30% insoluble materials. They are generally gentle and neutral, such as Kidz Pre Step, with 8.90% insoluble materials, abrasiveness of 0.24% and pH of 6.78.

[FIGURE 3 OMITTED]

4.2.6 Comparison of dental care products

Certain products are compared for informative purposes: a prophylactic toothpaste, whitening product, denture products, tongue cleaners, and the Brush-Ups "finger-tip toothbrush." Comparisons were also done with two identical tubes or two tubes from which samples were taken from the beginning and middle of the tube. In addition, this section presents the results of the tests done on some very popular homemade recipes and pure products (see table 10).

The comparison of the commercial toothpastes, some home toothpastes, and other dental products made it possible to evaluate these products in relation to each other. According to this comparison, no toothpaste is more abrasive than Nupro fine prophylactic paste, which is at 7.94 on the abrasiveness scale and is very alkaline. The denture paste, which has a low flow rate, stands out because of its gentleness, an abrasiveness of 0.42 and basic pH (7.6). Ban-A-Stain denture cleaner is very acidic (pH of 1.8). The 5-minute whitening gel is quite acidic and flows slowly. Products to clean the tongue are generally quite similar to each other but do not have the same flow. In addition, they are slightly acidic. Brush-Ups clean weakly, with an abrasiveness of 0, equivalent to that of water. However, we should point out that it was not possible to do all the tests because of this product's characteristics. Homemade recipes are similar from various points of view, including low abrasiveness and alkaline pH, which is higher with glycerine than with peroxide. Pure products, such as water, peroxide, and glycerine, have no abrasiveness, no insoluble materials, no foam, and a fast flow (from 9 to 10). Their differences relate to pH: neutral for water, alkaline for glycerine (7.87), and acidic for peroxide (4.92).

The last table (table 11) summarizes the results of some tests on toothpastes.

It should be noted that several so-called natural toothpastes fall into this category. In general, they contain plant extracts and abrasives that are not very soluble in water, such as chalk, which influence their abrasiveness. On the other hand, since they contain several fluorine derivatives, they prevent caries and the formation of tartar. Finally, their pH is generally neutral or basic.

To sum up, the results of this study of toothpastes done in 2005 provide new data on abrasiveness, pH, insoluble materials, flow, and foaming power, among other things. The most relevant data are analyzed below.

5. ANALYSIS

The following analysis allows us to scrutinize the results and make recommendations. Ideally, toothpastes should protect teeth and not present a risk. Certain toothpastes, with an acidic pH (5.5 or less), favour demineralization but have low abrasiveness. It should be noted that, although certain bacteria are vulnerable to these variations, others are highly resistant, such as streptococci, and remain active in acidic environments. (5) Thus these toothpastes should be recommended with caution when roots are exposed or in case of demineralization. Alkaline or basic toothpastes may be influenced by bicarbonate of soda, which has been recommended for centuries for its alkaline effect. (8) During tests, solutions of water and bicarbonate (1:1) had a pH of 8.4. According to Lehne and Winston, (9) factors other than hardness influence a product's overall abrasiveness, such as its composition and the size and shape of the particles it contains. In fact, the relatively high solubility of bicarbonate may contribute to its low abrasiveness. (9) Used dry, bicarbonate of soda could wear down dentin or enamel. It did in fact scratch the block of PMMA, which gives it a moderate abrasiveness level of 0.98. On the Mohs scale, sodium bicarbonate has a hardness similar to dentin (2), but its particles are very irregular. That is the very good reason why certain toothpastes contain micronized particles.

In 1994, Desautels and Labreche (1) noted the arrival of whitening agents, which now have a market share of 42%. It would be desirable if the terminology related to whitening could be standardized in the area of health. For example, pharmacists Than and Laviolette (28) suggest two categories of tooth whitening products: whitening agents such as WhiteStrips bands, which contain hydrogen peroxide, and toothpastes with whitening properties, which contain abrasives. The authors include recent abrasives such as aluminum trihydrate. The process of bleaching with peroxide seems to target tooth demineralization in order to replace calcium and phosphate ions with ions from fluoride or saliva. (22) In general, natural toothpastes and whitening toothpastes seem to be more abrasive than the others. Natural toothpastes often contain plant matter (29) that does not dissolve in water. Whitening toothpastes may contain very abrasive particles, such as alumina, (9) that may have a direct effect on surface wear. On the Mohs scale, (18) this metallic derivative is very hard and not soluble. Thus, caution is required when it comes to whitening agents.

It is unfortunate that North American manufacturers do not indicate the pH on their packaging, as is often done in Europe. (19) The RDA (26,27) is indicated on many European toothpastes (2) and it would be interesting to include it on products intended for other markets as well. Manufacturers are not required to provide a list of ingredients. However, such a list would contribute valuable information in light of the numerous chemicals available. A number of natural toothpastes go in the opposite direction by specifying the protective role of their ingredients, for example, vitamin C, which promotes gum healing.

With regard to commercial toothpastes, samples taken from two different tubes or from the beginning and middle of a single tube provided slightly different data. One sometimes finds air bubbles and changes in colour. Although it is possible that the equipment used to mix the solutions influenced the results, the human variable is unlikely to have contributed to these variations since a single person carried out all the tests. Thus, the probability that toothpaste is homogeneous throughout the tube is low. It should be noted that the two blocks of PMMA per mix did not always give the same results, even when the mix came from the same solution. Viewed microscopically, the blocks did not display identical wear. This comparison clearly indicates that the product is not uniform. Thus, the results must be put in perspective, as they are only valid for the quantities analyzed. This finding applies to all studies on this subject. Moreover, it should be emphasized that two tests are not sufficient to generalize the results. However, since Desautels and Labreche (1) did just one test per product, this study's results are more detailed, despite their limitations.

Several studies are now attempting to measure the effectiveness of therapeutic agents containing xylitol-fluoride, (30) triclosan, (31) chlorhexidine, (32) or amine fluorides and stannous fluoride, (33) which are supposed to prevent plaque and gingivitis, (34) or herbal toothpastes that are also said to prevent these problems. (29) Olive oil might even inhibit dental plaque when it is included in toothpaste. (35) Brushing with or without toothpaste has no effect on gum recession according to a very recent study by Versteeg et al., (36) but it should be noted that they studied a very limited number of toothpastes. Nevertheless, the choice of a manual or electric brush can influence abrasion. (5,37) On the other hand, in Europe, the characteristics of toothpastes (such as acidity), cleansing power, and the analysis of abrasives (for example, hydrated silica, calcium carbonate, and aluminum trihydrate) (2) have been studied for some years now. Saliva also plays a key role in the accumulation of plaque and the demineralization of enamel. (38) Other research results have revealed new antimicrobial agents that are effective to varying degrees against micro-organisms. (39) More than 500 types of micro-organisms, including bacteria, fungi, and sometimes amoebae, form a complex and dynamic community within the biofilm. (40) Thus, research into biofilm will reveal other aspects that will undoubtedly be taken into consideration in basic and clinical research. (41) These studies are even more detailed than before and they open up new perspectives in dental health. The new products related to the user's general state of health, such as the products designed for diabetics and the toothpastes that target specific kinds of oral health problems, are likely to increase since they meet the specific needs of the aging population.

The methodology and protocol were quite time-consuming, but they were necessary to produce the main observations of the members of the interdisciplinary team. The involvement of professionals with different backgrounds was important in the design and execution of the study and constitutes an asset. The analysis could be even more detailed, but this overview gives one an idea of the toothpastes appropriate for each customer's specific needs.

6. RECOMMENDATIONS AND SPINOFFS

This study has generated many spinoffs for the instructors and departments at College FXG who worked together in an interdisciplinary fashion. Before the study, instructors in the dental hygiene department deplored our lack of knowledge of toothpastes, and the entire department is proud to have contributed to advancing the profession. We should emphasize that this project was modest, simple, and relatively easy to implement. A subsequent update is possible at the College because much of the equipment is long-lasting and remains available to instructors. This valuable partnership provided the momentum needed to increase synergy within the whole department.

We anticipate circulating the results by means of a brochure, teaching materials, or lectures, in both French and English. Thus, it would be desirable to undertake a second phase, which would involve seeking out partners to disseminate the results of the study, for example. This kind of dissemination would be valuable for instructors, students, and professionals. In addition, with time, consumers would become better informed about the products available on the market and would therefore benefit from the spinoffs of such a study. We must point out that the dissemination of all the results must be approved by the dental hygiene techniques department at College FXG.

As for the limitations on the study, we should mention that the methodology and the manufacture of the brushing machine were very time-consuming. The information needed to reproduce the brushing machine can be obtained by applying to the plan designers. On the other hand, the same protocol could be used to include new toothpastes. The results are presented as percentages, but the ideal would be to determine the equivalency between the abrasiveness rate and RDA or REA. The latter measures are used by manufacturers and appear on the packaging of many European toothpastes. Certain information ought to be mandatory, for example, a list of ingredients, abrasiveness, pH, and insoluble materials. These variables should be considered when oral health professionals are advising their clients. On the other hand, it would be interesting to examine materials other than PMMA, since hundreds of products have come onto the market since 1964, when the primary study of materials similar to human enamel and dentin was done. To the best of our knowledge, the hardness of enamel has not been verified in children. This factor could be relevant in determining the minimum abrasiveness required to clean teeth. The maximum abrasiveness should take into consideration all of the exposed parts of the tooth, namely, the enamel (the hardest part) and the dentin (the softest part). Any other variable subject to Newton's law during brushing should also be examined in more depth, such as the force used during brushing and the choice of a manual or electric toothbrush, or even an ultrasonic one that acts on the biofilm at a distance.

Our study has made it possible to establish certain relationships between general concepts and specific concepts, while enabling us to formulate some concrete recommendations.

7. CONCLUSION

This study fulfilled its mandate and achieved its general objective, namely to update the available data on toothpastes. Forrest and Miller's (13,14) model proved to be useful for reconciling scientific data, the point of view of professionals, customers' needs, and the constraints of the environment, such as the construction of the brushing machine in Quebec City. Moreover, the addition of new variables made it possible to examine some aspects in more depth. The formulation of the methodology was time-consuming but crucial. The statistical processing provided descriptive results, thanks to the use of means, for example. The study determined that the abrasiveness of 75% of the products was between 0 and 1.99 on the scale, which is equivalent to the hardness of dentin. The mean percentage of insoluble materials is either between 30% and 40% or lower than 10%. As for foaming power, it is low in most products. Approximately half the products flow moderately fast, at a rate of about five drops per second. When it comes to pH, the vast majority of the products are neutral, while approximately 25% are very basic and 15% acidic (pH of less than 6). The composition of cosmetic and therapeutic toothpastes was also assessed, particularly their active agents. The majority are not approved by the CDA, although they have the same concentration of products. For example, most children's toothpastes contain 0.243% NaF, but only a minority are approved by the CDA. Finally, children's toothpastes are not very or not at all abrasive, and they contain few insoluble materials in general.

Other statistical tests are necessary to discover the links between the various characteristics of toothpastes. There is a call for a second phase focusing on the dissemination of results and educational materials in French and English.

This innovative study of some 200 products meets several needs. It meets the needs of dental care professionals for more accurate information on prevention. In addition, it allows manufacturers to detect new trends--and there are many--by analyzing flavours, modifying such ingredients as humectants, or adding ingredients specifically adapted to diabetics, or vitamins and minerals such as vitamin C, calcium and copper, which have an effect on the gums, periodontal bones, or biofilm. And the general public wants to know the properties of toothpastes, such as fruit-flavoured pastes, so they can buy an appropriate product. Abrasiveness becomes a risk factor when the product is too abrasive or too acidic, for example. The toothpaste should constitute a protective factor that reduces oral and dental problems such as caries, tartar, gingivitis, and hypersensitivity. This expanded vision of dental products opens up interesting prospects for research, as well as clinical spinoffs in the short, medium, and long term.

ACKNOWLEDGMENTS

We would like to extend our warmest thanks to the members of the interdisciplinary team. We sincerely thank the Continuing Education Committee of the Dental Hygiene Department at College FXG. We greatly appreciated the cooperation of coordinators and departments in this project. The project also benefited from the support of the College's administration, and we are very grateful. Finally, we would like to express our deep gratitude to everyone who provided us with services: Louise Robichaud and Maurice Robichaud for translating the abstract of a presentation to the FDI World Dental Federation into English, the instructors in dental hygiene, and the information services and secretarial services teams at College FXG.

A second team will now take over for phase 2, which should be equally interesting and relevant. Requests for reprints: contact Nadia Dubreuil, College FXG. Tel.: [phone]. E-mail: [e-mail].

Relationship between the project and sponsors

Funding for this study was provided by the Continuing Education Committee of the Dental Hygiene Department at College FXG. There is no relationship between any sponsors and the study of toothpastes. In the first phase, neutrality was preferred in order to ensure that the study was independent. The second phase will respect the same criteria with regard to the documents produced, while relying on new partnerships concerning, for example, the translation, production and dissemination of reprints and educational material.

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8. Wilkins E. Clinical practice of the dental hygienist. 9th ed. Philadelphia: Lippincott Williams & Wilkins; 2005.

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11. Canadian Dental Hygienists Association. L'hygiene dentaire: Definition et champ d'application. Ottawa: CDHA; 2002.

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14. Forrest JL, Miller SA. Evidence-based decision making in action: Part 2--Evaluating and applying the clinical evidence. J Contemp Dent Pract. 2003;4(1):42-52.

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19. Swiss Dental Hygienists. Dimensions. 2005;6:2.

20. Kandelman D. La dentisterie preventive. Montreal: Presses de l'Universite de Montreal; 1989.

21. Ciancio SG. Chemical agents: plaque control, calculus reduction and treatment of dentinal hypersensitivity. Periodontol 2000. 1995;8:75-86

22. Basting RT, Rodrigues AL, Serra M. The effects of seven carbamide peroxide bleaching agents on enamel microhardness over time. J Am Dent Assoc. 2003;134(10):1335-42.

23. Lavoie F. Les porte brosse a dents. Choix des dentifrices selon la population, les professionnels et les manufacturiers. Paper presented at the provincial symposium on public dental health. Quebec: June 2005.

24. Canadian Dental Association. Sceau de reconnaissance de l'ADC [on-line]. Ottawa: CDA; [cited 2005 Jun 14]. Available from: www.cda.ca.

25. Pickles MJ, Joiner A. "A new in vitro method for determining toothpaste abrasivity". J Dent Res. 2004; 83(Spec Iss A):4032.

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27. Hefferren JJ. A laboratory method for assessment of dentifrice abrasivity. J Dent Res. 1976;55(4):563-73.

28. Than C, Laviolette M. Les produits de blanchiment des dents vendus en pharmacie. Quebec Pharmacie. 2003;50(10):753-6.

29. Pannuti CM, Mattos JP, Ranoya PN, Jesus AM, Lotufo RF, Romito GA. Clinical effect of a herbal dentifrice on the control of plaque and gingivitis: a double-blind study. Brazilian Oral Res. 2003;17(4):314-8.

30. Iwata C, Nakagaki H, Morita I, Sekiya T, Goshima M, Abe T, et al. Daily use of dentifrice with and without xylitol and fluoride: effect on glucose retention in humans in vivo. Arch Oral Biol. 2003;48(5):389-95.

31. Bruhn G, Netuschil L, Richter S, Brecx M, Hoffmann T. Effect of a toothpaste containing triclosan on dental plaque, gingivitis, and bleeding on probing--an investigation in periodontitis patients over 28 weeks. Clin Oral Invest. 2002;6(2):124-7.

32. Van Strydonck DA, Demoor P, Timmerman MF, van der Velden U, van der Weijden GA. The anti-plaque efficacy of a chlorhexidine mouthrinse used in combination with toothbrushing with dentifrice. J Clin Periodontol. 2004;31(8):691-5.

33. Paraskevas S, Danser MM, Timmerman MF, van der Velden U, van der Weijden GA. Amine fluoride/stannous fluoride and incidence of root caries in periodontal maintenance patients. A 2 year evaluation. J Clin Periodontol. 2004;31(11):965-71.

34. Paes Leme AS, Dalcico R, Tabchoury CP, Del Bel Cury AA, Rosalen PL, Cury JA. In situ effect of frequent sucrose exposure on enamel demineralization and on plaque composition after APF application and F dentifrice use. J Dent Res. 2004;83(1):71-5.

35. Pretty IA, Gallagher MJ, Martin MV, Edgar WM, Higham SM. A study to assess the effects of a new detergent-free, olive oil formulation dentifrice in vitro and in vivo. J Dent. 2003;31(5):327-32.

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39. Tortora GJ, Funke BR, Martin L. Introduction a la microbiologie. Montreal: Editions du Renouveau Pedagogique; 2003.

40. Stoodley P. Biofilms, smile! You're on confocal scanning laser microscopy camera. In: Emerging trends in oral care. The biofilm revolution. Sci Amer. 2002;Jan:13-17. Symposium conducted by Philips Oral Healthcare. 2002.

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This article has been peer reviewed.

Editor's note: This article was published originally in French in the July-August 2006 issue of the journal (Vol, 40, No. 4). Due to the number of requests for an English version, we are publishing a translated version of the article.

by the Comite dentifrice of College Francois-Xavier-Garneau:* France Lavoie, DH, BA, MA; Nancy Feeney, DH; Lucie Mc Callum, DH; Marie-Josee Paquet, PhD, Chemistry; Yvon Fortin, BSc, Physical Sciences; Denis Nadeau, Tech., Physical Sciences; Andree Duhamel, BSc, Microbiology; Diane Lefebvre, Lab Tech.; Monique Roy, BSc, Chemistry; Sophie Boudreau, Tech., Chemistry; Louise Lefebvre, DH, BSc

* Special collaborative project of the Department of Dental Hygiene's Continuing Education Committee, the interdisciplinary team of the departments of Dental Hygiene, Physical Sciences, Chemistry and Biology, and the Physical Science Demonstration Centre of College FXG. College Francois-Xavier-Garneau, 1620, boulevard de L'Entente, Quebec, QC, G1S 4S7. Contact: France Lavoie at [e-mail].

Percentage  Action                          Ingredients

20% to 60%  Cleansing and polishing agents  Calcium carbonate, calcium
            Abrasive compounds to clean     pyrophosphate, dehydrated
            teeth and polishing agents to   dicalcium phosphate,
            obtain a smooth, shiny surface  anhydrous dicalcium
                                            phosphate, insoluble calcium
                                            metaphosphate (IMP),
                                            hydrated aluminum oxide,
                                            silica, silicates and
                                            dehydrated silica gels,
                                            synthetic amorphous
                                            silicates in gel form,
                                            complex salt of synthetic
                                            amorphous aluminum silicate
20% to 40%  Humectants                      Glycerine, sorbitol,
            Substances used to retain       propylene glycol
            water and prevent the product
            from air-drying
15% to 50%  Water                           Wilkins provides no further
                                            details
2% to 3%    Preservatives, sweeteners, and  Preservatives: alcohols,
            dyes                            benzoates, formaldehydes,
            Substances to prevent the       dichlorinated phenol.
            spread of bacteria, give a      Sweeteners: non-cariogenic
            pleasant taste, and make the    artificial sweetener,
            product attractive              sorbitol and glycerine (the
                                            latter two act as both
                                            humectants and sweeteners).
                                            Dyes: vegetable colouring.
1% to 2%    Therapeutic agents              For the time being,
            Medications or chemicals added  fluoridated toothpastes
            for specific preventive or      constitute the best
            treatment purposes              preventive agent. Added
                                            antibiotics: penicillin,
                                            tyrothricin. Ammoniac and
                                            enzyme-inhibiting
                                            toothpastes for research on
                                            caries: N-lauryl sodium
                                            sarcosinate and sodium
                                            dehydroacetate.
1% to 2%    Binders                         Hydrophilic organic colloids
            Substances preventing liquid    such as alginates and
            and solid ingredients from      synthetic cellulose
            separating                      derivatives
1% to 2%    Detergents                      Sodium lauryl sulphate, N-
            Foaming agents or surfactants   lauryl sodium sarcosinate,
                                            sodium cocomonoglyceride
                                            sulphonate
1% to 1.5%  Fragrances                      Essential oils, menthol,
            Compounds intended to make the  non-cariogenic artificial
            toothpaste attractive and mask  sweetener
            the taste

Table 1. General composition of toothpastes

Product name and number    Supplier *            Features

Oral-B 40 soft brush no.   Oral B                Rectangular shape and
  663904                                         flat surface, handle
                                                 cut in the physical
                                                 science centre
Fisher stopwatch no.       Fisher Scientific     Precision: 0.1 second
  92241896
10-ml serological pipette  Mohr                  Graduation: 0.1 to the
                                                 end
250-ml beaker no. 1003     Pyrex                 Wide, flat shape
15-ml centrifuge tube no.  Nalgene               Graduation: 0.1
  3103 0015
Fisher liquid soap no.     Fisher                Concentrate that leaves
  04342                                          no residue
Vortex stirrer no.         Sc. Industries        Three stirrers used
  K-500-2                                        simultaneously
Stirring hot plate no. PC  Corning               Set to maximum power
  351
Octagonal stir bar no.     Fisher Scientific     Length of 51 mm
  11451170
Electronic scales no.      Dewer                 Max.: 200 g, precision:
  10108379                                       0.001 g
Fisher pH-meter no. 00934  Fisher Scientific     Three calibrations,
                                                 adjusted to seven
Buffer solution, pH = 7    Fisher Scientific     Electrode kept in
  no. SB108B                                     neutral solution
Scott Light Work paper     Fisher Scientific     Fine fibres that do not
  tissues no. 02930                              damage surfaces
Desiccator no. 08-644      Fisher Scientific     Drying at room
                                                 temperature
Anhydrous calcium          Lab Mat               Drying product used in
  chloride no. CP-0108                           the desiccator
250-ml Erlenmeyer flask    Pyrex                 Vacuum assembly
  no. 10-040F
Black seal plug no.        Fisher Scientific     Adaptation between
  273836B8                                       Erlenmeyer and funnel
Fisher tube no. 14-150-2K  Fisher Scientific     Installed between plug
                                                 and faucet
2-clamp support for        Fisher Scientific     Fixed the assembly on
  Erlenmeyer no. 05-769-3                        the faucet
Coors Buchner funnel no.   Fisher Scientific     Flat perforated bottom
  60240                                          to hold filter and
                                                 solution
Whatman Glass microfibre   Fisher Scientific     High-performance glass
  quantitative filter no.                        fibre filter to hold
  1827 055                                       all kinds of materials
Premium finest glass       Fisher Scientific     Observation with phase
  slide no. 12-544-2                             contrast microscope
Premium finest coverglass  Fisher Scientific     Observation with phase
  no. 12-548-B                                   contrast microscope
Carl Zeiss West Germany    Opti-Ressources       Maximum enlargement:
  phase contrast                                 400x
  microscope, standard 14
JVC monitor no. TM-1400U   Opti-Ressources       Screen approximately
                                                 40 cm
Nikon CoolPix digital      Opti-Ressources       Black-and-white setting
  camera 5400
Pechiney Parafilm plastic  Pechiney              Protector on containers
  packaging no. 992
Distilled water            -                     Distilled water machine
                                                 in biology department
Wash bottle no. 0340922C   Fisher Scientific     Flexible plastic and
                                                 fine pipette
Brushing machine           FXG                   Designed and machined
                                                 in physical science
                                                 demonstration centre
18 X 9 X 5-mm PMMA blocks  Johnston Industrial   Cut in physical science
  (heat-cured              Plastics              centre
  polymethylmethacrylate)
Accessories: cylinders,    Fisher Scientific     Useful complementary
  cylinder stand,          for laboratory        items with no direct
  spatulas, pan, filter    items, Rona Hardware  influence on tests
  paper plate and clip,    and Bureau en Gros
  test-tube tape, fine
  brush for cylinders,
  brush to clean brushing
  pan, extension cord,
  pencils, rulers, etc.
Computer, software and     IBM and Microsoft     None
  in-house compilation     2003
  charts

* Contact the authors for more information on equipment, such as
supplier contact information.

Table 2. List of equipment, suppliers and certain features

Manufacturers              Number  Percentage

Colgate-Palmolive Canada   26      13%
Proctor & Gamble Inc.      26      13%
GlaxoSmithKline            19      10%
Church & Dwight Co. Inc.   11       6%
Oral-B                      7       4%
Omni Oral Pharmaceuticals   5       3%
Zooth                       3       2%
Others                     99      51%

Table 3: Toothpaste manufacturers

Colour            Flavour       Texture

White: 39%        Mint: 63%     Paste: 51%
Blue: 21%         Other: 22%    Gel: 29%
Green: 15%        Fruit: 6%     Liquid gel: 9%
2-3 colours: 12%  Gum: 5%       Gel and paste: 6%
Clear: 7%         Cinnamon: 4%  Other: 5%
Red: 7%           Citrus: 1%    Liquid: 1%
Pink: 6%
Orange: 3%

Format       Specific action

Tube: 82%    Anti-caries: 76%
Bottle: 12%  Whitening: 42%
Other: 6%    Anti-tartar: 26%
             Anti-gingivitis: 21%
             Sensitivity: 12%
             Multicare: 1%

Table 4. Breakdown of toothpastes according to colour, flavour, texture,
format, and specific action

                                             Moderately    Not very
               Very abrasive:  Abrasive:     abrasive:     abrasive: 0
               2 or more       1.37 to 1.99  0.88 to 1.36  to 0.87

Frequency and  48; 24.5%       38; 19.4%     40; 20.4%     70; 35.7%
  % (n = 196)
Example        Healthy Mouth   Arm & Hammer  Crest         Sensodyne-F
               Tea Tree at     3 Hour Fresh  Whitening     Revitalizing
               5.17            Breath at     Expressions,  at 0.61
                               2.38          mint at 2.17

Table 5. Abrasiveness scale

                            Neutral: 7 (7
                Basic or    [+ or -] 1 is
                alkaline:   considered as   Acidic: 4 to  Highly acidic:
                8 and over  neutral)        5.9           less than 4

Frequency and   56; 28.9%   108; 55.7%      20; 10.3%     10; 5.1%
  % (n = 194)*
Example         Tom's of    Colgate Total,  Biotene gel   Omnii Gel,
                Maine with  Advanced Fresh  at 5.60       natural at
                propolis    at 7.02                       3.17
                at 9.86

* Brush-Ups and bicarbonate were excluded from this test.

Table 6. pH measurements

                High: 40 or more   Medium: 20 to 39.99   Low: 0 to 19.99

Frequency and   27; 13.8%          85; 43.8%             82; 42.3%
  % (n = 194)*
Example         Nutrismile C pure  Weleda calendula      Prim'age 2-6
                with Citrus and    toothpaste at 27.95%  years, fluoride
                Spice at 56.45%                          500 ppm,
                                                         calcium and
                                                         provitamin B5,
                                                         strawberry
                                                         flavour at
                                                         16.65%

* Brush-Ups and bicarbonate were excluded from this test.

Table 7. Insoluble materials

                 High: 2 or more
                 Values                                Low: 0 to 0.99
                 representing     Moderate: 1 to 1.99  Values equivalent
                 double the       Values moderately    to or slightly
                 initial volume   greater than the     greater than the
                 or more          initial volume       initial volume

Frequency and %  18; 9.2%         79; 40.3%            97; 49.5%
  (n = 194)*
Example          Aim Fluoride at  GUM, Whitening Plus  Emoform-F at 0.6
                 2.50             at 1.85

* Brush-Ups and bicarbonate were excluded from this test.

Table 8. Foaming power

                                 Moderate: 5 [+ or -] 2    Slow: 0 to
                Fast: 7 or more  Values between 3 and 6.9  2.9

Frequency and   32; 16.5%        88; 45.4%                 74; 38.1%
  % (n = 194)*
Example         Thera Breath,    Colgate Icy Blast, 2 in   Crest Vivid
                oxygenating      1, toothpaste and         White at 0.25
                toothpaste with  mouthwash, at 6.65
                aloe vera and
                OXYD-8, at 7.8

* Brush-Ups and bicarbonate were excluded from this test.

Table 9. Flow rate

                                    Abrasiveness  Insoluble
Products                            (%)           materials (%)

Nupro prophylactic paste, fine      7.94          52.85
Polident denture paste              0.42          45.68
Ban-A-Stain denture cleaner         0              0.15
Plus+White whitening gel, 5-min.    0              0
  whitening
Brush-Ups mint teeth wipes          0              -
Breath-So-Fresh tongue cleaner      0.42          13.45
GUM, Fresh-R tongue cleaner         0.73           9.4
Gel-Kam Fruit and Berry oral care   0              0
  rinse
Gel-Kam Mint oral care rinse        0.24           0
Sensodyne-F Revitalizing, tube 1    0.85          21.95
Sensodyne-F Revitalizing, tube 2    0.61          22.7
Mentadent, beginning of tube        2             12.05
Mentadent, middle of tube           1.97          11.4
Water                               0              0
USP hydrogen peroxide 3%/10 vol.    0              0
USP glycerine                       0.06           0
Glycerine and 3% peroxide           0.06           0
Arm & Hammer, Cow Brand             0.98           0
  bicarbonate of soda, dry
Bicarbonate and water 1:1           0.06           0
Bicarbonate and water and peroxide  0.36           1
  1:1:1
Bicarbonate and peroxide 1:1        0              0
Bicarbonate and glycerine 1:1       0.12          24.05
Bicarbonate and glycerine           0.36           0
  (Desautels and Labreche) 0.8:1

                                    Foaming     Flow
Products                            power (mm)  (ml)   pH

Nupro prophylactic paste, fine      0            8.1   9.36
Polident denture paste              1.7          2.85  7.69
Ban-A-Stain denture cleaner         0.55         2.6   1.8
Plus+White whitening gel, 5-min.    1.2          2.25  6.325
  whitening
Brush-Ups mint teeth wipes          0           -      -
Breath-So-Fresh tongue cleaner      0.1          1.65  5.29
GUM, Fresh-R tongue cleaner         0.15         7.9   6.46
Gel-Kam Fruit and Berry oral care   0            8.25  3.6
  rinse
Gel-Kam Mint oral care rinse        0.55         7.55  3.2
Sensodyne-F Revitalizing, tube 1    0.25         4.25  8.3
Sensodyne-F Revitalizing, tube 2    0            4.35  8.315
Mentadent, beginning of tube        1            5.6   8.08
Mentadent, middle of tube           1.5          2.75  8.05
Water                               0           10     6.9
USP hydrogen peroxide 3%/10 vol.    0           10     4.92
USP glycerine                       0            0.6   7.87
Glycerine and 3% peroxide           0.2          9.15  6.19
Arm & Hammer, Cow Brand             -            0     -
  bicarbonate of soda, dry
Bicarbonate and water 1:1           0            9.45  8.4
Bicarbonate and water and peroxide  0           10     8.24
  1:1:1
Bicarbonate and peroxide 1:1        0           10     8.34
Bicarbonate and glycerine 1:1       0           10     8.32
Bicarbonate and glycerine           0           10     7.76
  (Desautels and Labreche) 0.8:1

Table 10. Comparison of dental care products

Very abrasive: 2% or over
Abrasive: 1.35% to 1.99%
Moderately abrasive: 0.88% to 1.36%
Not very abrasive: 0.0% to 0.87%
Children's toothpaste

AmF: amine fluoride
MFP: sodium monofluorophosphate
NaF: sodium fluoride
NF: no fluoride
SnF2: stannous fluoride
E: antibacterial enzymes
NMH: nicomethanol hydrofluoride
PN: potassium nitrate
SC: strontium chloride
P: pyrophosphate
T: triclosan

No.  Toothpaste                            Fluoride   pH    Abrasiveness

185  Nupro fine, prophylactic paste        NaF         9.4  7.94%
124  Jason, Healthy Mouth, pure,           NF          7.5  5.17%
     natural & organic, tea tree oil,
     clove and cinnamon
125  Jason, Nutrismile C, pure, natural &  NF          7.3  5.06%
     organic, citrus & spice
136  Nature's Gate, natural toothpaste,    NF          8.5  4.72%
     sodium bicarbonate, Creme de
     Peppermint with plants
137  Nature's Gate, natural toothpaste,    NF          8.4  4.54%
     sodium bicarbonate, Creme de Mint
     with plants
155  Pearl Drops, whitening toothpaste,    MFP         6.6  4.30%
     mint
126  Jason, Sea Fresh, Deep Sea, pure,     NF          6.8  4.11%
     natural and organic, mint
113  Green Apple Natural Toothpaste with   NF          8.5  3.78%
     calcium and vitamin C
170  CleanicDent, stain removal            NaF         7.3  3.64%
 41  Colgate MaxFresh, with Mini Breath    NaF         7.2  3.33%
     Strips, Whitening, Clean Mint
112  Zesty Orange Natural Toothpaste with  NF          8.1  3.30%
     calcium and vitamin C
119  Tom's of Maine, natural toothpaste    NF          9.6  3.29%
     with propolis and myrrh, fennel
117  Tom's of Maine, natural toothpaste    NF          9.9  3.27%
     with propolis and myrrh, spearmint
 40  Colgate MaxFresh, with Mini Breath    NaF         7.2  3.22%
     Strips, Whitening, Cool Mint
116  Homeodent 2, plants and chlorophyll   MFP + NaF   6.7  3.18%
134  Auromere, herbal toothpaste,          NF          8.6  3.05%
     Original Licorice
111  Frosty Mint Natural Toothpaste with   NF          8.2  2.93%
     calcium and vitamin C
 74  Close-Up, mint gel                    MFP         6.4  2.85%
 45  Colgate Herbal White, mint, lemon     MFP        10    2.77%
     extracts
109  Aquafresh Triple Protection,          MFP         8.4  2.76%
     Advanced Freshness
 49  Aquafresh Triple Protection,          MFP         8.4  2.61%
     children's, Bubblemint

Table 11: Summary table: Very abrasive toothpastes
Abrasivite des dentifrices 2004-2006