Knowledge for Clinical Practice. Dentifrices

Transcription

1 DENTAL LEARNING A PEER-REVIEWED PUBLICATION Knowledge for Clinical Practice A Guide to Dentifrices Fiona M. Collins, BDS, MBA, MA INSIDE Earn 2 CE Credits Written for dentists, hygienists and assistants Integrated Media Solutions Inc./DentalLearning.net is an ADA CERP Recognized Provider. ADA CERP is a service of the American Dental Association to assist dental professionals in identifying quality providers of continuing dental education. ADA CERP does not approve or endorse individual courses or instructors, nor does it imply acceptance of credit hours by boards of dentistry. Concerns or complaints about a CE provider may be directed to the provider or to ADA CERP at org/cerp. Integrated Media Solutions Inc./DentalLearning.net designates this activity for 2 continuing education credits. Approved PACE Program Provider FAGD/MAGD Credit Approval does not imply acceptance by a state or provincial board of dentistry or AGD endorsement. 2/1/2016-1/31/2020 Provider ID: # AGD Subject Codes: 016, 258 Dental Learning, LLC is a Dental Board of California CE Provider. The California Provider # is RP5062. All of the information contained on this certificate is truthful and accurate. Completion of this course does not constitute authorization for the attendee to perform any services that he or she is not legally authorized to perform based on his or her license or permit type. This course meets the Dental Board of California s requirements for 2 units of continuing education. CA course code is

2 DENTAL LEARNING A Guide to Dentifrices ABSTRACT A vast selection of dentifrices is currently available, with various active ingredients for therapeutic benefits and many inactive ingredients that provide for nontherapeutic benefits and properties. Since the introduction of fluoride dentifrices, many additional agents have been introduced and increasingly multi-benefit dentifrices have become available. When recommending a dentifrice for specific patients, it is important to understand the function of ingredients, their efficacy in specific dentifrices and other factors that could influence dentifrice selection and recommendation. Introduction Basic requirements for a dentifrice include the ability to control and prevent dental diseases and conditions in various combinations caries, sensitivity, gingivitis (periodontal disease), and halitosis; and to control and/or remove dental plaque and stain. Increasingly, patients regard whitening as a basic requirement for a dentifrice and LEARNING OBJECTIVES The overall objective of this article is to provide the participant with information on dentifrice ingredients and their functionality. Upon completing this course, the participant will be able to: 1. Delineate the difference between active and inactive ingredients; 2. List and describe the categories of active ingredients and their mechanisms of action; 3. Describe and review the types of abrasives present in dentifrices; and 4. Review the types of inactive ingredients and their functions. ABOUT THE AUTHOR Fiona M. Collins, BDS, MBA, MA Dr. Fiona M. Collins has authored and presented CE courses to dental professionals and students in the United States and internationally, and has been an active author, editor, writer, speaker and trainer for several years. Fiona is a member of the American Dental Association, the ADA Standards Committee working groups, Chicago Dental Society, and the Organization for Safety, Asepsis and Prevention (OSAP). She is the ADA representative to AAMI and a Fellow of the Pierre Fauchard Academy. Dr. Collins earned her dental degree from Glasgow University and holds an MBA and MA from Boston University. AUTHOR DISCLOSURE: Dr. Collins has received honoraria for speaking or writing from oral care companies. She is the CE Editor for Dental Learning. Dr. Collins does not have a leadership position or a commercial interest in Church & Dwight, the commercial supporter of this course. Dr. Collins can be reached at fionacollins@comcast.net. SPONSOR/PROVIDER: This is a Dental Learning, LLC continuing education activity. COMMERCIAL SUPPORTER: This course has been made possible through an unrestricted educational grant from Church & Dwight. DESIGNATION STATEMENTS: Dental Learning, LLC is an ADA CERP recognized provider. ADA CERP is a service of the American Dental Association to assist dental professionals in identifying quality providers of continuing dental education. ADA CERP does not approve or endorse individual courses or instructors, nor does it imply acceptance of credit hours by boards of dentistry. Dental Learning, LLC designates this activity for 2 CE credits. Dental Learning, LLC is also designated as an Approved PACE Program Provider by the Academy of General Dentistry. The formal continuing education programs of this program provider are accepted by AGD for Fellowship, Mastership, and membership maintenance credit. Approval does not imply acceptance by a state or provincial board of dentistry or AGD endorsement. The current term of approval extends from 2/1/2016-1/31/2020. Provider ID: # EDUCATIONAL METHODS: This course is a self-instructional journal and web activity. Information shared in this course is based on current information and evidence. REGISTRATION: The cost of this CE course is $29.00 for 2 CE credits. ORIGINAL RELEASE DATE: February REVIEW DATE: January EXPIRATION DATE: December REQUIREMENTS FOR SUCCESSFUL COMPLETION: To obtain 2 CE credits for this educational activity, participants must pay the required fee, review the material, complete the course evaluation and obtain a score of at least 70%. AUTHENTICITY STATEMENT: The images in this course have not been altered. SCIENTIFIC INTEGRITY STATEMENT: Information shared in this continuing education activity is developed from clinical research and represents the most current information available from evidence-based dentistry. KNOWN BENEFITS AND LIMITATIONS: Information in this continuing education activity is derived from data and information obtained from the reference section. EDUCATIONAL DISCLAIMER: Completing a single continuing education course does not provide enough information to result in the participant being an expert in the field related to the course topic. It is a combination of many educational courses and clinical experience that allows the participant to develop skills and expertise. PROVIDER DISCLOSURE: Dental Learning does not have a leadership position or a commercial interest in any products that are mentioned in this article. No manufacturer or third party has had any input into the development of course content. CE PLANNER DISCLOSURE: The planner of this course, Casey Warner, does not have a leadership or commercial interest in any products or services discussed in this educational activity. She can be reached at cwarner@dentallearning.net. TARGET AUDIENCE: This course was written for dentists, dental hygienists, and assistants, from novice to skilled. CANCELLATION/REFUND POLICY: Any participant who is not 100% satisfied with this course can request a full refund by contacting Dental Learning, LLC, in writing. Please direct all questions pertaining to Dental Learning, LLC or the administration of this course to cwarner@dentallearning.net. Go Green, Go Online to take your course Copyright 2015 by Dental Learning, LLC. No part of this publication may be reproduced or transmitted in any form without prewritten permission from the publisher. DENTAL LEARNING 500 Craig Road, First Floor, Manalapan, NJ Director of Content JULIE CULLEN Creative Director MICHAEL HUBERT Art Director MICHAEL MOLFETTO

3 A Guide to Dentifrices manufacturers have incorporated ingredients that may offer a whitening effect. Use of the dentifrice must also appeal to the senses for compliance with use, and it must have a consistency that makes brushing with it possible. To these ends, both active and inactive ingredients are incorporated in various combinations. Current dentifrices offer a plethora of choices and ingredients. One of the resulting challenges is understanding the role of the various ingredients in these dentifrices. Generally, patients look for products that clean and whiten their teeth a quest that is thousands of years old without understanding all of the functions that dentifrices can perform. As dental professionals, it is helpful to dissect the ingredients list and claims for dentifrices as a prelude to recommendations. Anatomy of a Dentifrice Label All dentifrices contain both active and inactive ingredients. The active ingredients are defined by the FDA as active drug ingredients. These offer specific therapeutic benefits and are listed first, followed by the list of inactive ingredients, which includes those responsible for the structure of the dentifrice and for sensory appeal. If more than one active ingredient is present, they are listed alphabetically. Similarly, inactive ingredients are listed in order of descending concentration. Packaging claims can include claims for caries prevention, enamel strengthening, anti-erosion, anti-plaque, anti-gingivitis, anti-calculus (anti-tartar), relief of sensitivity, whitening, anti-halitosis, and more general claims such as freshens breath. Marketing claims do not necessarily indicate superiority over another product, unless specifically stating so and having a scientific basis for doing so. Some dentifrices carry marketing claims based on a particular ingredient, while another dentifrice with the same ingredient may not carry that claim. Some dentifrices may not carry a second therapeutic claim that would make the dentifrice a dual drug and require a lengthy process to go through the FDA. A dentifrice could also make a claim that, for instance, it was a polisher or whitener while being as effective, no more effective, or less effective, than a dentifrice that does not make that claim. These facts relate to the importance of knowing what is in a particular dentifrice, what those ingredients do and the efficacy of those ingredients, preferably in the particular formulation that is being used or recommended. It is also important to check for the presence of ingredients that may be contraindicated or relatively contraindicated for a particular patient. Inactive Ingredients Inactive ingredients in dentifrices include surfactants, abrasives, humectants, thickening agents (binders), preservatives, buffering agents, sweeteners, coloring agents (dyes), flavoring agents, and water. Some abrasives provide additional benefits not associated with inactive ingredients; with the exception of abrasives and surfactants, all other inactive ingredients can be broadly categorized into structural inactive ingredients and sensory inactive ingredients. Structural inactive ingredients A number of inactive ingredients provide for the structure of the dentifrice. These include humectants, binders, preservatives, buffering agents and water. Humectants prevent the dentifrice from dehydrating and keep it moist. Examples include sorbitol, xylitol, propylene glycol, glycerol, and polyethylene glycol. The use of sorbitol or xylitol as a humectant also adds some sweetness to the dentifrice. Buffering agents are used to maintain a favorable ph for dentifrices, preventing them from being too acidic or alkaline. Preservatives are included to prevent microbial growth. Examples include sodium benzoate and methyl paraben. Thickening agents (binders) thicken or bulk up the dentifrice and bind all of the ingredients together. Examples include January

4 DENTAL LEARNING carrageenan, cellulose, and xanthan gum. Surfactants are detergents and cause the dentifrice to foam. Examples include sodium lauryl sulphate (SLS), sodium lauroyl sarcosinate, and cocoamidopropyl betaine. Together with the dentifrice abrasive, they play a role in the removal of dental plaque by loosening it from the tooth surface, and suspending it in an emulsion that is then removed physically during brushing. This is the same manner in which detergents used for other purposes work. If a dentifrice is high-foaming, it contains a higher level of surfactants than a low-foaming dentifrice. The labelling should be checked to see which surfactant(s) is/are included in a dentifrice before recommending it to patients who experience recurrent aphthous ulcers suspected of being associated with SLS sensitivity. 1 Some studies have found a decreased incidence of recurrent aphthous ulcers in patients using an SLS-free dentifrice while others have not, and one study found a lower level of recurrent aphthous ulcers with a low-sls dentifrice than with a regular SLS or SLS-free dentifrice. 2,3 Although the association between the use of SLS and recurrent aphthous ulcers is not definitive, if a patient is sensitive to SLS then either a low-sls or SLS-free dentifrice can be recommended. Similarly, if patients indicate that they have intolerance or sensitivity to benzoates or other substances, the labelling should be checked to see whether or not the dentifrice being selected or used contains the ingredient in question and if so an alternative found. Sensory inactive ingredients Sensory inactive ingredients are added to dentifrices to make them appeal to the senses. Sweeteners and flavoring agents make the taste pleasant, encouraging dentifrice use. Noncariogenic sweeteners used in dentifrices include sodium saccharin, sodium cyclamate, and Acesulfame-K. These noncariogenic sweeteners are not metabolized by cariogenic bacteria, thus providing sweetening without resulting in cariogenic acid attacks. Polyols used in dentifrices as sweeteners include xylitol and sorbitol. Note that packaging may state contains xylitol and based on this wording, which is also seen on other dental product packaging, it is tempting to conclude that the xylitol provides anti-caries protection. However, unless present in a dentifrice at an appropriate level for anti-caries efficacy, the xylitol is present for its sweetening effect only (or as a humectant). In addition, anti-caries claims cannot be made for xylitol in the US. Flavorings were traditionally mint variants; they also include cinnamon, vanilla and fruit. Coloring agents make the dentifrice visually appealing. They are also added as market differentiators for example, a colored stripe in a white dentifrice. FD&C #1 and #5 dyes are used in dentifrices as coloring agents; although dentifrices are not intended for consumption, these dyes are food additives and safe if consumed. Dentifrices may have the appearance of clear colored gels or opaque pastes for an opaque appearance, titanium dioxide is included as one of the dentifrice ingredients. (Table 1) Sensitivity to flavorings (especially cinnamaldehyde) and colorings used in dentifrices and foods is relatively common and should be considered. 4,5 FD&C #5 (tartrazine, a yellow dye) is another example of an ingredient that an individual may have an intolerance or sensitivity to, 6 and for which the labelling should be checked if this is the case. Abrasives Abrasives are present in dentifrices to facilitate the removal of biofilm (dental plaque) and stain. Without any abrasive, effective removal of stain would not occur. Patient compliance with brushing is inadequate, 7 and the mouthfeel and cleaning provided by a dentifrice can actually aid compliance. This was demonstrated in 1 in vivo study where some participants using a dentifrice without any abrasive dropped out of the study. 8 4

5 A Guide to Dentifrices Abrasives used in dentifrices include silica-based, phosphate-based, and carbonate-based ingredients as well as other ingredients such as silicates, aluminum oxide, and clays. The most frequently used dentifrice abrasives are silicas, while phosphate-based abrasives include dicalcium phosphate dihydrate, calcium pyrophosphate, and tricalcium phosphate. The carbonate-based group include calcium carbonate, sodium bicarbonate (baking soda), and magnesium carbonate. Table 2 contains a list of commonly-used abrasives, together with their sources. The abrasivity of dentifrices is determined by the abrasive present, is noted by its Radioactive Dentin Abrasivity (RDA), and is tested on enamel using the Radioactive Enamel Abrasivity test (REA), while a stand-alone material can be measured in Mohs hardness. Dentin has a Mohs hardness of , and the higher the Mohs hardness of an abrasive, the more abrasive it is. For example, alumina with a Mohs hardness of greater than 9 would be much more abrasive than diclacium phosphate dihydrate or baking soda, which both have a Mohs hardness of 2.5 and is approximately the same hardness level as dentin. 9 The RDA of a dentifrice and level of abrasive are not the only factors responsible for plaque removal cleaning efficacy. Recent baking soda dentifrice studies have demonstrated significant removal of plaque compared to positive control antimicrobial dentifrices. In cross-over studies, baking soda dentifrice was found to have greater plaque reductions. 10 A parallel 4-week study with measurements after single brushings found greater plaque reduction with baking soda compared to an antimicrobial dentifrice, particularly in harder-to-reach areas. 11 Baking soda has low abrasivity and is rapidly cleared from the gingival sulcus. 12 It is therefore thought that dissolved baking soda is responsible and that this may reduce the Table 1. Sensory inactive ingredients Sweeteners Sodium saccharin; sodium cyclamate; xylitol; sorbitol; Acesulfame-K Flavoring agents Cinnamaldehyde; mint; vanilla; fruit Coloring agents FD&C #1; FD&C #5 Opaquers Titanium dioxide Table 2. Dentifrice abrasives and sources Silicas Derivative of sand, soda ash, or caustic and sulfuric acid Dicalcium phosphate dihydrate Aluminum oxide Calcium carbonate Sodium bicarbonate Magnesium carbonate Derivative of calcined limestone and phosphoric acid Bauxite; corundum Primarily through precipitation from lime water and carbon dioxide; calcite; chalk; seashells; eggshells Derivative of trona and carbon dioxide Magnesite; derivative of magnesium and calcium carbonate January

6 DENTAL LEARNING viscosity of plaque by disturbing its matrix, or by reducing bacterial co-adhesion and bacterial adhesion to the teeth. Although most dentifrice abrasives are considered inactive ingredients, there are a few that do provide therapeutic benefits. A dentifrice containing dicalcium phosphate dihydrates (dical) and fluoride was found in another study to offer greater caries prevention than a control fluoride dentifrice. 13 Dentifrice whitening agents Whitening is a cosmetic benefit, rather than a therapeutic benefit and the ingredients used in dentifrices for a whitening effect are considered inactive ingredients. Abrasives provide for the whitening effect in the majority of dentifrices making a whitening claim. While smokers dentifrices are typically highly abrasive this is not necessarily the case, and most dentifrices carrying a whitening claim on the packaging had higher abrasivity levels in a recent assessment. 14 An RDA of up to 250 is considered to be safe for normal daily use. Note also that the RDA does not predict the REA - it is possible for one to be high and the other low with the same product. 15 A recent in vitro study found that the RDA of 26 dentifrices ranged from 36 to above 250 and their pellicle cleaning ratio a measure of stain removal performance ranged from 25 to 138. Generally, but not linearly, there is a relationship between the RDA and stain removal the more abrasive the dentifrice, the more stain it will typically remove. The pellicle cleaning ratio (PCR) is a measure of cleaning ability (stain removal). 14 Enamel polish (EP) is a measure developed to assess the capability of a dentifrice to impart polish and luster to the enamel (which influences the perception of whitening). 14 (Figure 1) Tooth wear by abrasion is the result of many factors, including the complex relationship of hardness, abrasivity and particle shape; RDA and REA in vitro test data should not be used as the only criteria for dentifrices in vivo. 16 Dentifrice abrasives are effective against extrinsic stain stain that is on the surface of the tooth. A number of ingredients can be incorporated into dentifrices marketed with a whitening claim. Fine, rounded abrasives: These offer cleaning and whitening benefits. They Figure 1. RDA, PCR and EP of dentifrices RDA PCR EP Brand A Brand B Brand C Brand D Brand E Brand F Brand G Source: Adapted from Schemehorn BR, Moore MH, Putt MS. Abrasion, polishing, and stain removal characteristics of various commercial dentifrices in vitro. J Clin Dent. 2011;22(1):

7 A Guide to Dentifrices remove extrinsic stain and smooth the surface of the tooth (unlike with tooth bleaching procedures where intrinsic stain is removed). As a result, light interacts with the tooth surface differently thereby giving the perception that the tooth is whiter (lighter). Amorphous calcium phosphate: Dentifrice containing amorphous calcium phosphate has been found to offer a whitening benefit. This is due to the microscopic enamel defects being filled with amorphous calcium phosphate deposits which smooths out the surface of the enamel and improves luster. As with the use of fine rounded abrasives, the perception is a whiter, lighter appearance. 17,18 Baking soda: This offers a whitening benefit in dentifrices in addition to stain removal. High concentrations of baking soda in dentifrices were found in one in vitro study to reduce the yellowness of teeth by reducing intrinsic stain. 19 Although sodium bicarbonate (baking soda) has a very low RDA compared to other dentifrices, it was found in one study to remove chlorhexidine stain at a level similar to a control fluoride dentifrice, thought to occur by the action of baking soda lifting stains. 20,21 Hydrogen peroxide: Low levels of hydrogen peroxide (typically 1%) are added to some whitening dentifrices. Only limited data is available on this concentration of hydrogen peroxide incorporated into dentifrices. The mechanism of action involves the generation of oxygen bubbles that are intended to help lift stain from the tooth surface. Unlike whitening treatments however, only transient contact occurs during toothbrushing and the concentration is low. One recent study found a significant whitening effect for a 1% hydrogen peroxide fluoride dentifrice that included sodium tripolyphosphate and a high-cleaning silica base. 22 A study examining the effect of 1% hydrogen peroxide in dentifrices on reductions in yellowness of teeth found no significant whitening effect. 23 The solubility of hydrogen peroxide may also influence the effect of hydrogen peroxide in dentifrices. Pyrophosphates and tripolyphosphates: These have an affinity for the tooth surface and repel stain. Sodium hexametaphosphate: This has a strong affinity for the tooth surface, which helps to prevent stain deposition, and can also help remove stain for a whitening effect. Clinical study comparisons of the stain reduction obtained with stannous fluoride/sodium hexametaphosphate dentifrice compared to triclosan/ copolymer whitening dentifrice led to the conclusion that both were equally effective at reducing stain. 24 Since a potential drawback of historical stannous fluoride formulations was its propensity to result in staining, this underscores the efficacy of sodium hexametaphosphate. Whitening is a highly desired benefit, as is the polishing effect of dentifrices. Interestingly, in one recent study aside from two non-silica products, dentifrices advertised for polishing ability generally were no more effective than other products. 14 Clinical Indications and Active Ingredients The most universally-used active ingredient in dentifrices is fluoride. Other examples of active ingredients include the use of antimicrobial agents that are anti-plaque and anti-gingivitis (and may also be anti-caries). The following sections address ingredients used for a number of indications. Caries control (anti-caries) Fluoride Most dentifrices contain fluoride for caries control, providing a replenishing dose of fluoride when patients brush. The evidence for the anti-caries efficacy of daily fluoride dentifrice use is strong. 25 The anti-caries efficacy of fluoride is such that for patients at low risk for caries it has been recommended January

8 DENTAL LEARNING that the use of a fluoride dentifrice alone may provide sufficient protection against dental caries. 26 Fluoride dentifrices are effective against coronal caries in the primary and permanent dentition and against root caries. A pooled reduction of 24% (D(M)FS) was found in a meta-analysis of 70 clinical trials. 27 The most recent Cochrane review (2011) of fluoride dentifrices found a statistically significant anti-caries effect in children and adolescents at fluoride concentrations of 1,000 ppm or greater. The mechanisms of anti-caries activity at the concentration of fluoride present in dentifrices involve the prevention of demineralization through the presence of low levels of fluoride ions intraorally, and the promotion of remineralization. Fluoride dentifrice options available depend on geography in the US and Canada the available options are sodium fluoride, stannous fluoride and sodium monofluorophosphate. These are regulated in the United States by the Food and Drug Administration under the Anticaries Monograph for dentifrices, and are effective for caries control. 28,29,30 The majority of dentifrices in the United States contain 1,000 1,100 ppm fluoride, and are effective for caries prevention. 31 (Table 3) The American Dental Association s recommendations on the use of fluoride dentifrices by children recently changed. For children under age 3, a smear of toothpaste (amount the size of a grain of rice) is recommended from the time the first tooth Table 3. ADA recommendations on amount fluoride dentifrice use 32 Time of eruption of first tooth until age 3: A smear Age 3 until age 6: A pea-sized amount Age 6 and over: A strip erupts. From age 3 until age 6 it is recommended that a pea-sized amount of toothpaste be used, and from age 6 onwards a strip of toothpaste is recommended. 32 These recommendations are to maximize the caries preventive benefits of fluoride while helping to reduce the risk of fluorosis as a result of ingestion of excess fluoride from all sources in total during tooth development. Brushing should be supervised for children, and in the case of very young children performed by the parent/caregiver. The American Academy of Pediatric Dentists also issued revised recommendations on fluoride use in dentifrices that also support up to these amounts. 33 Reduced fluoride concentration dentifrices have also been suggested elsewhere for young children in order to reduce the risk of fluorosis (including, but not only, through accidental ingestion of fluoride dentifrice). However, a review conducted in 2010 that included 75 studies led to the conclusion that there was no statistically significant caries protective effect for fluoride dentifrices at concentrations of ppm compared to placebo. 34 Xylitol Xylitol has been shown to provide anticaries benefits when used as an active ingredient in dentifrices at a concentration of 10%, and in dentifrices containing sodium fluoride or sodium monofluorophosphate provides additive anti-caries benefits of 12% and 10% respectively. 35,36 Cariogenic bacteria cannot metabolize xylitol, and are thereby unable to produce acid required for demineralization. In addition, a bacterial starvation effect occurs. The FDA only recognizes fluorides as active ingredients in the Anticaries Monograph. Non-traditional remineralizing agents Over the last decade, a number of remineralizing agents have been investigated and introduced into dentifrices, based on calcium and phosphate technologies. While few actual clinical trials have been conducted on these technologies, some clinical trial 8

9 A Guide to Dentifrices results are currently available on specific formulations in dentifrices. Soluble calcium and phosphate ions in a 1,100 ppm fluoride dentifrice (ACP) formulation were shown in 1 study of head and neck radiation patients to significantly remineralize and prevent root caries. 37 One study found a 2% casein phosphopeptide dentifrice to provide caries protection equivalent to 0.76% sodium monofluorophosphate dentifrice in high-risk children. 38 Relief of hypersensitivity Desensitizing dentifrices typically contain either potassium nitrate or stannous fluoride, both of which have been used for several decades as effective desensitizers. The active ingredients in dentifrices responsible for relief of hypersensitivity work by one of two mechanisms: by preventing the transmission of neural signals from the tooth at the time of stimulation of the nerve endings, or by occluding the open dentinal tubules thereby preventing stimulation of free nerve endings. Potassium nitrate: At a concentration of 5%, the only concentration approved by the FDA for desensitization, potassium nitrate is the main desensitizing agent used to prevent the transmission of neural signals. This works by increasing the concentration of extracellular potassium ions which blocks repolarization of the myelinated A-fibers and thereby prevents neural signals from being transmitted. 39 (Figure 2) Five percent potassium nitrate has a long history of safe use in dentifrices, 40,41 and is compatible with fluoride and other dentifrice ingredients. Other potassium-based ingredients such as potassium chloride have also been used. Stannous fluoride: Desensitizing dentifrices that occlude the dentinal tubules typically contain stannous fluoride. This works by precipitating the stannous (tin) ion to occlude the dentinal tubules, and also has a long history of use. 42,43 (Figure 3) One study found a 44% reduction, based on the Schiff air test, at 8 weeks using a stannous fluoride/sodium hexametaphosphate dentifrice compared to use of sodium fluoride dentifrice. 44 Sodium fluoride and sodium monofluorophosphate are poor desensitizers in dentifrices. 45,46 Figure 2. Blocking neural signals Figure 3. Open and occluded dentinal tubules Open Occluded January

10 DENTAL LEARNING Non-traditional desensitizers Non-traditional ingredients are now also available that have been shown to provide relief from hypersensitivity. Recent studies have shown that the addition of calcium salts to a fluoride dentifrice results in sensitivity relief, 47 while other novel formulations can also provide for sensitivity relief through precipitation and occlusion of open dentinal tubules. Calcium and phosphate contained in baking soda dentifrice has been shown to effectively relieve dentinal hypersensitivity, with reductions of 61% over 8 weeks compared to a control dentifrice. 48 Calcium sodium phosphosilicate: Dentifrice containing calcium sodium phosphosilicate has also been shown clinically to effectively desensitize exposed dentin. 49,50 Arginine/calcium carbonate: While not available in the United States, dentifrice containing arginine, calcium carbonate and 1,450 ppm fluoride has been shown to be an effective desensitizer. 51 Protection against erosion Dental erosion results from exposure of the teeth to extrinsic and intrinsic acids of nonbacterial origin. Sources of extrinsic acids include highly acidic drinks and foods, while gastric acid is an intrinsically-sourced acid. Erosion results in loss of minerals from the surface of the teeth (demineralization) and softening of the tooth surface, leaving it vulnerable to abrasion, attrition, further erosion and perhaps dental caries. Dental erosion is now a commonly-observed problem and dentifrices are marketed with claims for enamel strengthening and resistance to acids. These may contain fluoride or fluoride plus additional ingredients specifically, calcium and phosphate. Fluoride has a long history of use in preventing demineralization and promoting remineralization, albeit with a traditional focus on caries prevention. Some of the recently introduced calcium and phosphate technologies have also been shown to have these capabilities. One other consideration is that for patients with dental erosion a dentifrice with a lower abrasivity has been recommended to help avoid abrasion of the eroded tooth surface. It is recommended that patients should not brush immediately after being exposed to extrinsic or intrinsic acids, to give time for the ph to return to normal and thereby avoid brushing acid against the teeth. Anti-plaque and anti-gingivitis Anti-plaque dentifrices have the ability to reduce the amount of plaque present to influence gingivitis and/or caries. Several dentifrice ingredients have been investigated for their anti-plaque anti-gingivitis activity. Triclosan/copolymer: Dentifrice containing 0.3% triclosan/copolymer has been shown to significantly reduce plaque levels due to the bactericidal effect of triclosan. In a meta-analysis of 16 clinical trials of at least 6 months duration comparing triclosan/copolymer dentifrice with a control dentifrice, the plaque reduction was 48% (weighted mean difference) and the gingivitis reduction 26%. The reduction in plaque severity was 15% and the reduction in gingivitis severity was 12%. In vitro testing has also shown an anti-inflammatory effect, and influence on associated chemicals, for triclosan/copolymer. 52,53 Stannous fluoride: This is also bactericidal and bacteriostatic, and has been shown to alter bacterial growth and to inhibit bacterial adhesion. 54,55 A review of trials led to the conclusion that stannous fluoride is more effective than sodium fluoride dentifrice in reducing gingivitis. 56 Stannous fluoride has demonstrated anti-inflammatory properties in in vitro testing. 57 One in vivo assessment found no differences in plaque regrowth with the use of stannous fluoride dentifrice or triclosan/ copolymer dentifrice when subjects used dentifrice slurries (negating any influence 10

11 A Guide to Dentifrices of abrasive cleaning). 58 One comparative two-year study on periodontal health found statistically equivalent periodontal attachment gains and pocket depth reduction for 0.454% stannous fluoride/ sodium hexametaphosphate and triclosan/copolymer dentifrices. 59 Zinc citrate: Dentifrices containing 2% zinc citrate have been found to offer anti-plaque and anti-gingivitis benefits with reductions of 25% and 19% respectively over a 6-month period. Greater gingivitis reductions were observed where gingivitis was initially more severe. 60 Anti-calculus (anti-tartar) Anti-calculus agents in dentifrices inhibit the formation of calculus, and are effective in reducing supragingival calculus. Calculus forms through the mineralization of, primarily, dental plaque. Several anti-calculus agents are available for inclusion in dentifrices. Pyrophosphates and tripolyphosphates: Tetrapotassium, disodium and tetrasodium pyrophosphates all inhibit calculus formation primarily by interfering with crystal growth during calculus formation, 61 and have a long history of use. In two clinical trials, significant reductions in calculus formation of 20% - 25% compared to control dentifrices were found with the use of pyrophosphates as anti-calculus ingredients in dentifrices. 62,63 When recommending dentifrices containing pyrophosphates it is important to check with the patient that he or she is not sensitive to these formulations, which could result in oral ulcerations and irritations. 64 Zinc salts: Incorporated into dentifrices as zinc citrate or zinc chloride, these salts reduce calculus formation through the inhibition of crystal growth and have been shown to be effective in various dentifrice formulations. 65,66 Copolymer: The copolymer contained in triclosan/copolymer dentifrice is known to inhibit crystal growth associated with calculus formation, and to reduce calculus formation. 67,68 One study with triclosan/copolymer dentifrice found a calculus reduction of 34.8% compared to a fluoride control dentifrice. 69 Sodium hexametaphosphate: This compound has been shown to significantly reduce calculus formation through inhibition of crystal growth and has greater surface affinity than pyrophosphate. 70 Sodium hexametaphosphate was shown in one study to reduce calculus formation by 55% over 6 months compared to a control fluoride dentifrice. 71 Dentifrices and Xerostomia Dentifrices are available that are marketed for patients with xerostomia. Fluoride is a particularly important component of dentifrices for patients with xerostomia and increased concentrations offered by an Rx dentifrice are frequently recommended for use. A gentle, low abrasive dentifrice helps prevent further discomfort on dry and irritated oral mucosa. Other considerations include the ability to offer relief from hypersensitivity where required, a low-foaming paste that is nonirritating, and the ability of the dentifrice to aid in mouthfeel through a moisturizing/ lubrication effect. Dentifrices for xerostomia may also contain enzymes offered to boost natural protection, or additional ingredients such as calcium lactate aimed at aiding remineralization, may or may not contain sodium lauryl sulphate, pyrophosphates, benzoates and xylitol and thus may or may not be indicated for a specific patient depending on his or her requirements and health status. As with other dentifrices and patients, reading the packaging and understanding the ingredients is key in selecting the dentifrice of choice for a xerostomic patient. Conclusions Understanding the labelling and ingredients listed on the packaging for dentifrices is an important step in knowing which dentifrice can best deliver the desired benefits January

12 DENTAL LEARNING safely and effectively for a given patient and lets dental professionals source evidence for efficacy. Confirming that ingredients to which a specific patient may have sensitivities are not in a particular dentifrice is also necessary. Many dentifrices also now offer multiple benefits in one and although fluoride dentifrices were the standard, desirable additional therapeutic benefits are now available - such as a whitening benefit, antiplaque and anti-gingivitis claims, anti-tartar claims and anti-sensitivity claims, plaque and gingivitis reductions. Assessing claims, ingredients, and efficacy, as well as what is needed and what the patient wants are key considerations in recommending dentifrices. References 1 Skaare AB, Kjaerheim V, Barkvoll P, Rölla G. Skin reactions and irritation potential of four commercial toothpastes. Acta Odontol Scand. 1997;55(2): Neppelberg E, Costea DE, Vintermyr OK, Johannessen AC. 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