Current Understandings and Future DirectionsManaging Dental Erosion:

A Symposium Sponsored by:

Dear Colleagues,

On behalf of Procter & Gamble Oral Health, it is my pleasure to share with you highlights from the American Association for Dental Research symposium, titled ‘Managing Dental Erosion: Current Understandings and Future Directions,’ held March 17, 2016.

While the dental research community has made great strides in preventive dentistry over the past 60 years with breakthroughs such as the introduction of �uoride dentifrices and varnishes, dental erosion has arisen as a major new challenge for clinicians in recent years. First identi�ed approximately 25 years ago, since then the prevalence of dental erosion has increased dramatically in children, adolescents and adults. This is especially of concern since the enamel and dentin loss associated with this multifactorial condition is irreversible.

Fortunately, we’ve recently learned a great deal about dental erosion, its progression and strategies to prevent it. Therefore, we are pleased to share with you the most current learnings on dental erosion which our distinguished panel presented during the symposium.

Please �nd enclosed synopses of talks by Dr. Noble, Dr. White and Prof. West providing an overview of the current state of diagnosing and managing dental erosion, research methodologies, and clinical perspectives that can help you with treatment planning. I hope you will �nd this publication informative and of practical bene�t for you and your patients.

Sincerely,

J. Leslie Winston, DDS, PhD

Director, Global Oral Care Professional & Scienti�c Relations andClinical Operations

Procter & Gamble Oral Health

J. Leslie WinstonDDS, PhD

Ward NobleDDS, MS, MSEd

Dental erosion involves the chemical dissolution of dental hard tissues without bacterial involvement. Research on erosion has expanded in recent years to the broader condition of erosive tooth wear (ETW) which also factors in the effects of attrition and abrasion.

Erosive Tooth WearETW begins when exposure to dietary or intrinsic acid causes a drop in salivary pH. The saliva then comes into contact with the acquired pellicle and then the tooth surface, where acidic changes initiate tooth surface loss (TSL). Calci�ed material is removed producing a softened, demineralized surface layer. This exposes fragile organic material (collagen) that is easily removed, leaving the tooth vulnerable to further TSL through abrasion and attrition, e.g., by brushing or bruxing.

The Response of Enamel and Dentin to Acid Challenges

Enamel and dentin are distinctly different with respect to their organic and inorganic composition and therefore react differently to acid challenges (Table 1). In enamel, demineralization of the prisms leaves friable microscopic areas of tooth structure that are gradually broken off in cycles resulting in TSL (Fig. 1). In dentin, there is less calci�ed material and therefore less bulk loss during demineralization, however greater areas of exposed organic material remain. These collagen �brils are subject to frictional forces and degradation by proteolytic enzymes including matrix metalloproteinases (MMPs). The result is progressive TSL (Fig. 2). While the effects of an acid challenge on enamel and dentin are different, both are at risk for TSL. Clinically, this makes it highly desirable and bene�cial that early intervention occur as soon as erosion is observed.

Defining and Diagnosing Dental Erosion

Inorganic material 85% 47%

Organic material 2% 33%

Water 11% 21%

Table 1. Content of enamel and dentin

Enamel Dentin

Figures 1 and 2. Erosion of enamel (1) and dentin (2). (Lussi et al, 2011).Images courtesy of Karger.

After demineralization, enamel prisms remain.

After demineralization, a fragile organic matrix and degradation of collagen fibers by MMPs result.

1 2

Patient Age and Risk FactorsWhile it is accepted that deciduous ETW may foretell future problems in the permanent dentition, studies on the prevalence of ETW in young children are inconclusive. An overall prevalence of 30% has been found in a meta-analysis of studies in teenagers and young adults with at least 1 erosive lesion, and the condition becomes even more prevalent with age. ETW is episodic throughout life and can start in infancy. Different etiologies typically play more of a role at different ages. Figure 3 shows a case involving erosion and attrition. Risk factors for ETW include: 1) dietary habits (amounts, frequency, manner of consuming acidic foods and beverages); 2) gastric re�ux (GERD, bulimia, pregnancy vomiting); 3) xerostomia – reduced salivary �ow decreases acid dilution and clearance; and, 4) exposure to mechanical insults such as hard foods, improper toothbrushing and bruxism. The severity of acid attacks varies with the pH of acid and its buffering capacity, whether a drink is swished/sipped/gulped and its contact time, the thickness of the acquired pellicle and salivation. Reduced salivary �ow represents the greatest risk factor and must be evaluated. ETW is irreversible and, if observed in children or adolescents, it can be expected to progress unless intervention occurs. In looking at minor erosion, the patient’s age, habits, and whether wear is physiological or pathological should be considered. Early diagnosis is especially important as patients typically do not seek care until they experience pain or an esthetic problem.

The Basic Erosive Wear Examination (BEWE)

The BEWE, introduced by Bartlett, Ganss and Lussi in 2008, is used to assess the level of erosion. Table 2 shows the criteria for sextant scores from 0 to 3, which are summed to obtain a cumulative score that is the basis for determining interventions (Table 3).

Defining and Diagnosing Dental Erosion Ward Noble

Table 2. BEWE Scores and Criteria

0 No ETW

1 Initial loss of surface texture

2a Distinct defect; hard tissue loss involving <50% of the surface area

3a Hard tissue loss involving ≥50% of the surface area

Score Criteria

aDentin often involved

“An overall prevalence of 30% has

been found in a meta-analysis of

studies in teenagers and young

adults with at least 1 erosive lesion,

and the condition becomes even

more prevalent with age.”

Figure 3. Multifactorial ETW with erosion and attrition

Challenges in the Management of ETWManagement challenges for ETW include early diagnosis of erosive lesions, the initiation of preventive strategies and behavioral changes, and early intervention with minimally-invasive restorative procedures. Early diagnosis should include charting of erosive lesions, sensitive teeth, staining, and making note of areas of exposed dentin. In addition, a risk assessment should be performed.

ConclusionsIn conclusion, the bottom line in the management of ETW is early diagnosis, initiation of preventive measures, and early intervention to avoid the need for extensive and invasive care.

Table 3. Cumulative BEWE Scores and Management Guidelines

No ETW: 0 - 2 • Routine maintenance and observation • Repeat at 3-year intervals Low: 3 - 8 • Oral hygiene, dietary assessment • Routine maintenance and observation • Repeat at 2-year intervals Medium: 9 -13 • Oral hygiene, dietary assessment • Routine maintenance • Fluoride measures • Avoid restorations • Repeat at 6-12 month intervals High: ≥14 • Oral hygiene, dietary assessment • Routine maintenance • Fluoride measures • Repeat at 6-12 month intervals • Consider restorations

Cumulative Score General guidelines for management

Defining and Diagnosing Dental Erosion Ward Noble

“Management challenges for ETW

include early diagnosis of erosive lesions,

the initiation of preventive strategies and

behavioral changes, and early

intervention with minimally-invasive

restorative procedures.”

Dr. Noble is a Professor at the Arthur A. Dugoni School of Dentistry, University of the Pacific, San Francisco, CA, USA.

Patients should be taught preventive habits that reduce the risk of ETW. These include:

• Staying hydrated

• Rinsing with water before brushing

• Brushing with a stannous �uoride toothpaste before eating

• Not brushing for at least 1-2 hours after an acid challenge

Donald J. WhitePhD

Methodologies used to assess dental erosion fall into 2 groups – those measuring total mineral loss from enamel (and dentin) due to lesion progression, and those measuring the surface properties of lesions.

Lesion Progression MethodsLesion progression can be assessed using sound enamel slabs subjected to cycles of acid challenges and salivary remineralization in vitro, or by in situ testing with patients swishing/drinking beverages that deliver acid challenges to enamel slabs worn in an appliance. Using the same methods, the ef�cacy of preventive measures to inhibit lesion progression can be assessed. Lesion progression in enamel and dentin can be measured using microradiography, contact pro�lometry, and non-contact (optical) pro�lometry; the latter two additionally measure surface roughness. A fourth option, confocal laser scanning microscopy (CLSM), measures total lesion progression and the softened zone. A recent study compared CLSM, contact pro�lometry and non-contact pro�lometry and found all three methods gave similar results in measuring the loss of enamel.

Surface Layer MeasurementsSurface layers can be assessed using in vitro or in situ models. Methods of analysis can include scanning electron microscopy (SEM) (Fig. 1), quantitative light �uorescence or optical coherence tomography which measure changes in the surface zone and are used to determine surface roughness. Additional methods include acid solubility testing and atomic force microscopy (Fig. 2). Replica SEMs can be used with in situ research to measure the surfaces of eroded lesions or softened zones of enamel lesions. An additional method of analyzing the surface layers, secondary ion mass spectroscopy (SIMS), can be used to measure the composition of the surface layer and to show material �rmly deposited at the surface.

Current Methodologies to Assess Dental Erosion

“By focusing on lesion progression

models, the total microns lost and

the ability of a given therapy to

protect against erosive progression

can be determined.”

a b

Figure 1. SEM showing loss of enamel (a) and, at greater magnification, the softened layer at the advancing front of the lesion (b). (Lussi et al, 2011). Images courtesy of Karger.

Current Methodologies to Assess Dental Erosion Don White

Hardness recovery, hardness loss inhibition, surface composition/�uoridation and solubility reduction measurements can all be used to assess the mechanisms and ef�cacy of a proposed preventive therapy against dental erosion. Protocols used include surface preparation using an acid challenge and measurement, treatment steps, surface measurements after secondary acid challenges (typically citric acid, or for in situ studies orange juice), and then measuring rehardening after re-immersion in saliva. Different responses to acid challenges have been observed in surface roughness assessments in studies of different �uorides and the concentration of �uorides.

Progression of the Erosive LesionThe 3 stages in progression of an erosive lesion are initial surface softening, progressive loss of enamel and the creation of a lesion that involves dentin.

Figure 2. Atomic Force Microscopy

Note less structural loss on the slab treated with stabilized stannous fluoride toothpaste.Stannous fluoride deposits are insoluble in concentrated acid and provide protection, especially at low pH.

Tooth treated withSodium FluorideToothpaste

Tooth treated withStabilized StannousFluoride Toothpaste

w/o Acid Challenge Acid Challenged

Visualization of the tooth surface demonstrating protection

Current Methodologies to Assess Dental Erosion Don White

By focusing on lesion progression models, the total microns lost and the ability of a given therapy to protect against erosive progression can be determined. The two methods available to help prevent dental erosion are to protect it by, in effect, ‘galvanizing’ the surface with deposits that are acid-resistant, and to remineralize the surface between acid challenges. It has been possible to demonstrate superior ef�cacy for stannous �uoride in reducing surface loss when measured in vitro, using microradiography following several cycles of erosive challenges, immersion in saliva, and treatment with �uorides (Figure 3).

Reduced progression of erosive lesions has also been observed with stabilized stannous �uoride toothpaste in situ compared with sodium �uoride toothpaste. In a study by Hooper and colleagues the bene�t of stannous �uoride increased over time (Figure. 4).

“It has been possible to

demonstrate superior ef�cacy for

stannous �uoride in reducing

surface loss when measured in

vitro, using microradiography

following several cycles of erosive

challenges, immersion in saliva,

and treatment with �uorides.”Surf

ace

Ena

mel

Lo

ss (

µm

) 30

25

20

15

10

5

0

Crest® Pro-Health®

Sensodyne®ProNamel®

Colgate®Total®

Crest® CavityProtection

(ref control)

Arm & Hammer®Enamel Care

Figure 3. Surface enamel loss with marketed dentifrices using a lesion progression model with microradiography (Faller et al, 2011).

* Significantly di�erent vs all treatments (p<0.05)

*

Figure 4. In situ erosion protection (Hooper et al, 2007).

Test Formulation (SnF2)

Benchmark Paste (NaF)

Negative Control

1

-0.6

-1

-1.5

-2

-2.5

-3

-3.50 5 10 15

Mic

rons

of

enam

el (

lost

)

Days of Product Use

Current Methodologies to Assess Dental Erosion Don White

In real life, many foods and drinks are below pH4 and are highly acidic (Table 1). This is important when considering the pHs of foods and drinks, and also important to consider when performing erosion testing as different pHs will result in different results. During an acid challenge, the tooth starts to dissolve in an effort to recreate an equilibrium, by releasing calcium, phosphate and �uoride salts. At pH4, more than 90% of the �uoride salt released is present as �uoride ions, which protects the surface against demineralization. At pH2, it is overwhelmingly hydro�uoric acid that is present, rather than �uoride ions; as a result, insuf�cient �uoride ions are present to protect the tooth surface, leading to dissolution of the surface layer of the tooth. Stannous �uoride has been shown to provide unique protection against acids, particularly at a low pH (e.g., orange juice, ~2.6).

ConclusionsThere are a variety of analytical methods, models and protocols that can be used to study erosion. Some measure lost mineral while others measure changes in the surface zone. Protocols differ depending on whether studies will be used to analyze the surface zone or to produce erosive lesions and measure effects on the progression of erosion. Depending on the method used, dramatic differences can be seen in the observed ef�cacy of various topical agents.

“Stannous �uoride has been shown to provide

unique protection against acids, particularly at a

low pH (e.g., orange juice, ~2.6).”

Dr. White is a Victor Mills Society Research Fellow at The Procter & Gamble Company, Mason, OH, USA.

Table 1. pH of Beverages

Pure Water 7.0Milk 6.6Tea 6.2Co�ee and milk 5.3Black co�ee 5Tomato Juice 3.7Sprite 3.29Diet Pepsi 3.03Gatorade 2.92Dr. Pepper 2.90Fruit Punch 2.82Orange Juice (Minute Maid) 2.64Coke Classic 2.53Reference: Battery Acid 1.0

Beverage pH

*Sources: University of Ottawa; General Dentistry, March/April 2007; preventdisease.com

Nicola WestBDS, FDS RCS, PhD FDS (Rest Dent)

Pathological tooth wear was rarely seen in ancient civilizations, and the majority of it was abrasion or attrition. While its prevalence and severity have increased in children and adults, erosive tooth wear (ETW) is a totally preventable condition for most individuals. Progressive ETW can lead to poor esthetics, sensitivity, loss of function, and sometimes loss of self-esteem. (Figure 1)

Early identi�cation and prevention are key, and by the time lesions are clearly visible to the patient, restorative intervention and life-long dental treatment may be required. Regularly screening all patients for ETW makes it possible to diagnose erosive lesions at the earliest possible stage and to implement preventive and treatment measures to preserve tooth structure and to help stop further damage.

Risk Assessment for ETWThe risk assessment should consider all risk factors and include asking patients if they are aware of any tooth wear, or have sensitive teeth. The risk assessment includes determining dietary habits; oral hygiene regimens; the presence of gastroesophageal re�ux symptoms, eating disorders; xerostomia; and, whether the patient is a lactovegetarian, taking acidic medications, or occupationally at risk (e.g., wine tasters). A number of factors in�uence the rate of progression and extent of lesions, and must be considered during the risk assessment. These factors include the frequency, amount and duration of exposure to an erosive challenge; high consumption of carbonated drinks, acidic fruits and vegetables; drinking alcohol; the manner in which acidic agents are consumed, e.g., holding or swishing acidic drinks in the mouth which prolongs contact; and, having acidic drinks at night when salivary �ow is low.

Clinical Strategies to Prevent and Manage Dental Erosion

Figure 1. Facial view of dentition of a 23 year-old-male with ETW

“Progressive ETW can lead to

poor esthetics, sensitivity, loss

of function, and sometimes loss

of self-esteem.”

Note the chipping edges, exposed dentin and surface pattern

Clinical Strategies to Prevent and Manage Dental Erosion Nicola West

Clinical ExaminationA full examination and tooth indexing for erosion (BEWE) should be performed. The patient should be assessed for erosion, abrasion, attrition, abfraction, tooth wear etiology, recession, dentinal hypersensitivity, occlusion, salivary �ow rate, and staining (which would suggest erosion is not occurring at that time). (Figure 2)

Biological FactorsPoor salivary �ow impacts clearance of acid and buffering, and therefore delays a return to the resting pH. The saliva also supplies the pellicle, with the evidence showing that the pellicle can prevent and stop progressive erosion unless overwhelmed by a strong acid challenge. Synergistic wear may occur, for example, by the tongue abrading softened enamel palatally and lingually.

Preventing and Managing Dental ErosionOnce a diagnosis of dental erosion is made, an overall preventive management program is needed. ETW management focuses on oral hygiene practices, home care, professional care, and individually tailored advice, to prevent further erosion and manage lesions. If preferred, moderate/severe cases can be referred for treatment. All etiological factors shouldbe assessed.

Figure 2. Image of young 30-year-old with all types of wear.

“ETW management focuses on

oral hygiene practices, home

care, professional care, and

individually tailored advice, to

prevent further erosion and

manage lesions.”

Clinical Strategies to Prevent and Manage Dental Erosion Nicola West

Oral Hygiene Practices and Home CareIt is recommended that patients with ETW brush for no more than 2 minutes and maximum twice-daily. Normally, manual and powered brushing cause virtually no enamel loss and minimal dentin loss. Based on a recent study using in situ enamel slabs, it took about 2 hours to see early repair following an acid challenge; this suggests that brushing should occur at least 2 hours after an acid challenge.

Patients with erosion can bene�t from twice-daily use of stannous �uoride toothpaste, because polyvalent metal ions interact with the tooth surface to form an acid-resistant insoluble layer. In fact, the recent consensus report by the European Federation of Conservative Dentistry notes that oral hygiene products containing stannous �uoride or stannous chloride, such as toothpastes or mouth rinses, have the potential to slow the progression of ETW. Additional options include recommending a calcium phosphate-based or bioactive glass home use product to promote remineralization.

Professional CareOral health education and advice must be individualized. Preventive care can include �uoride varnishes. Tooth surface protective coatings may also be indicated and dentinal hypersensitivity requires treatment or use of a desensitizing toothpaste. If intrinsic acid erosion is present, the patient should be referred for medical assessment and care. Restorative and bonding materials are only used if absolutely necessary to reduce sensitivity, improve esthetic considerations or restore function. For noncarious cervical lesions, it may be preferable to avoid restorative care, particularly for early lesions. (Figure 3)

Patients should be given advice on simple, practical ways to reduce the risk of erosive tooth wear such as dietary advice and modifying habits. Table 1 contains a list of areas to consider when tailoring patient advice. Regular reassessment and monitoring are needed to determine if ETW has been halted and to provide patients with advice and care.

Figure 3. Noncarious cervical erosive tooth wear

“In fact, the recent consensus report

by the European Federation of

Conservative Dentistry notes that

oral hygiene products containing

stannous �uoride or stannous

chloride, such as toothpastes or

mouth rinses, have the potential to

slow the progression of ETW.”

Clinical Strategies to Prevent and Manage Dental Erosion Nicola West

ConclusionsIn conclusion, ETW is multifactorial and its prevalence is increasing, especially in young adults. Advanced ETW causes patients to experience problems with esthetics, function, and pain, and creates treatment dilemmas for dental professionals. Effective management of ETW includes screening and evaluation of all etiological factors, preventive and restorative care, and using the least invasive therapy possible. Stannous �uoride or stannous chloride has been shown to slow the progression of erosive tooth wear. ETW must be effectively managed, with a focus on preventive care at the earliest stages, and monitoring and evaluation of ETW management should be performed regularly during recall sessions.

Table 1. Individually tailored advice

Dietary advice Reduce intake and frequency of acidic foods and drinks

Eat cheese/milk after acid challenges

Additional calcium content in food and beverages

Drink cold rather than warm beverages (if acidic)

Rinse with sodium bicarbonate to help increase the pH after dietary acid challenges

Chewing gum Chew nonacidic gum to stimulate saliva

Prof. West is an Honorary Consultant in Periodontology, University of Bristol Dental School and Hospital, Bristol, UK.

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