Main

Striking clinical examples of attrition were seen in patients with bruxism. Abrasion was attributed to tooth brushing or occasionally to habits such as chewing on a pipe stem. Erosion was seen in patients with symptoms of gastric reflux2,3 and later was recognised in patients with anorexia4 or bulimia5 or in patients with unusual dietary habits.6 In some cases erosion has been recognised as an occupational disease where workers have been exposed to acidic fumes, for example in factories making batteries.7,8 It is also recognised among wine-tasters9 (Type 4,5).

Over the past 10–15 years, however, there has been a steady increase in reports of erosion seen especially in young adults, adolescents10 (Fig. 1) and young children as noted particularly in the UK National survey.11 The cause of this erosion has been largely linked to the high consumption of soft drinks, both fruit juice and carbonated drinks, by these age groups. This link has been made largely in Europe and the problem has received little attention in the literature coming from the USA12,13 (Type 4).

Figure 1
figure 1

Clinical appearance of erosion on the palatal surface of upper incisor teeth in a patient who consumed daily large quantities of carbonated drinks

Diagnosis and severity

In order to prevent or reduce the non-carious destruction of tooth substance it is important first of all to:

  • Recognise that the problem is present

  • Grade its severity

  • Diagnose the likely cause or causes and,

  • Monitor progress of the disease in order to assess the success, if any, of preventive measures.

Collectively the various manifestations of non-carious tooth destruction have been termed tooth wear which conveniently allows for discussion of the problem without the obligation to meet all the precise definitions of each manifestation of the condition. Indeed many patients present with tooth wear that is the result of several aetiological factors that do not fall conveniently into one or other of the categories, attrition, abrasion or erosion (Figs 2,3). Careful observation by the dentist or hygienist at a routine visit is still probably the most usual way for tooth wear to be seen. Tooth wear may be present in patients with gastro-oesophageal reflux disease (Figs 4,5,6), bulimia and anorexia. It is clearly important for doctors and nurses treating patients with these conditions to be aware of the possibility that the patient also has severe tooth wear.

Figure 2
figure 2

Erosion on the palatal surface of maxillary incisor teeth, note the 'step' in the dentine caused by abrasion in the dentine by the lower incisors

Figure 3: Appearance of erosion in maxillary teeth of a teenage patient who consumed large quantities of carbonated drinks and also had a history of gastric reflux.
figure 3

Note the remains of incisal enamel at the gingival margin and erosion of the palatal cusps of the premolar and molar teeth

Figure 4
figure 4

Clinical appearance of maxillary anterior teeth in a patient with gastric reflux disease — note the enamel at the palatal gingival margin and the approximal surfaces

Figure 5: Clinical appearance of maxillary posterior teeth in a patient with erosion and gastro-oesophageal reflux disease.
figure 5

The erosion is largely confined to the palatal aspects of these teeth

Figure 6: Clinical appearance of mandibular posterior teeth in a patient with erosion and gastro-oesophageal reflux disease.
figure 6

The erosion is largely confined to the buccal aspects of these teeth

Once diagnosed, it is important that the location of the tooth wear and its severity be recorded. Several indices are available for this, ranging from the relatively simple index of Eccles and Jenkins14 (Type 4), that was designed for recording the severity of erosion, through the more detailed modification of the same index proposed by Lussi15 and the detailed Tooth Wear Index of Smith and Knight16 (Type 4) that is somewhat cumbersome to use at first but gives a good record of wear on each tooth surface enabling monitoring of the progression of tooth wear. It is also not limited to tooth erosion as are most of the other indices. In epidemiological studies the degree of inter- and intra- examiner variability in detecting and scoring tooth wear may be as great a problem as determining the aetiology. Careful calibration of examiners is helpful. For an individual practitioner, clinical experience may not be sufficient for his or her purposes and even a brief examination and second opinion by a colleague may help confirm the diagnosis, its severity and possible aetiology. Study casts are clearly a useful record of the status at any particular time and can be used to monitor progression of tooth wear. Computer-aided analysis of direct imaging of the affected teeth, impressions or study models are being developed but have not yet reached the stage of being a useful clinical tool for general practice 17,18 (Type 4). For routine clinical purposes, tooth wear should be recorded separately for the anterior and posterior teeth. The clinician should note the tooth wear as being: in enamel only; into dentine; or severely affecting the tooth or series of teeth for example as seen frequently in erosion of the palatal surfaces of four maxillary incisor teeth.

Aetiology and history taking

Following diagnosis of the presence of tooth wear, the clinician should attempt to determine the main aetiological factors. This will partly be based on clinical experience: examination of wear-facets; restorations that stand proud of the surrounding enamel; loss of vertical dimension; and the pattern of tooth wear. For example, a pattern of tooth wear involving the palatal surface of maxillary molar teeth, buccal surfaces of mandibular molars and palatal wear of maxillary anterior teeth is strongly suggestive of erosion caused by gastric acid. Nevertheless, other factors may play a part in the overall clinical picture. If there is a loss of occlusal enamel in the molar teeth the consequent loss of vertical dimension may produce 'step-like' wear facets palatally on the maxillary anterior teeth (Fig. 2), especially if the enamel has also been lost on these surfaces (Figs 5-6). The patient may also show other signs of more severe bruxism. A particular diagnostic problem is the condition sometimes termed abfraction where cervical erosions occur in several teeth thought by some authors19,20 (Type 4) to be caused by lateral occlusal forces acting in an acidic environment. These conditions may be found in a patient with bruxism who also has gastric reflux or who consumes acidic foods or beverages frequently.

Good history taking is essential to determine the consumption of carbonated drinks, fruit juices and other dietary factors that may contribute to the observed tooth wear.15 Medication, particularly frequent use of asthma inhalers containing steroid21,22 (Type4) or effervescent medications,23 should be checked as they may contribute to tooth erosion. Habits, including tooth brushing, that could contribute to tooth wear should be investigated with careful questions. It is important not to indicate that any blame for the clinical findings is being placed on the patient, otherwise a false history will be obtained. This is especially true when there are financial implications for the patient, for example the possibility of discretionary payments for necessary dental treatment, should the tooth wear be deemed not to be the 'fault' of the patient. The possibility of gastro-oesophageal reflux should be considered, not only bulimia and anorexia that patients are understandably reluctant to admit to, but also other possible causes of reflux including hiatus hernia.24 It may be necessary for the dentist to refer the patient to a gastroenterologist for investigations including gastroscopy and 24-hour monitoring of oesophageal pH that is the 'gold standard' for diagnosis of gastro-oesophageal reflux disease.25 Prompt diagnosis of reflux will in most cases lead to medication or possibly surgery to reduce reflux that will, in turn, remove the erosive challenge to the teeth (Type 4,5).

Tests of salivary function, particularly measuring salivary buffer capacity, may reveal contributing factors to tooth wear. There is no doubt that saliva plays an important role in the protection of enamel from erosion by acid, both by supplying the components of the acquired pellicle that coat the enamel surface and by promoting remineralisation of the enamel surface following acid attack. Clinical studies of the relationship between erosion and low salivary buffer capacity have, however, given conflicting results (Type 4).25,26,27 Careful history taking and clinical examination bearing in mind a possible mixed aetiology of tooth wear and including questions on diet, reflux disease and functional habits should help the practitioner arrive at a correct diagnosis.

Prevention of tooth wear

Preventing tooth wear is not the same as preventing caries. Dental caries is regarded as a disease that will affect most people in the world to some extent during their lifetime. This inevitability of caries developing, at least historically, was a strong stimulus to the development and promotion of preventive measures, especially those based on fluoride use and oral hygiene. Developed countries have experienced, by and large, higher prevalences of caries than less developed countries and their need for preventive measures has, therefore, been greater. Well-structured prevention programmes based on fluoride, organised dental examinations and regular recall and even financially subsidised treatments have become available that not only protect non-diseased teeth but also reduce the cariogenic challenge by removing the diseased tissue.

Tooth wear is a different and, in many ways, more difficult preventive problem. It has been regarded, until recently, as a problem for individual patients rather than being community based. With the high prevalences particularly of tooth erosion recorded in some surveys11,28 (Type 4), it is arguable that this type of tooth wear at least has now achieved the status of a community-wide dental problem in several countries. Undoubtedly tooth wear that can be attributed to a coarse diet, to rituals such as filing down teeth and also to environmental factors can all be found in developing countries. Prevention of tooth wear in these circumstances calls for cultural and economic changes that lie outside the scope of this review.

Although tooth wear is increasingly recognised to be a problem, it is difficult to predict which individuals will be affected and true prevention is therefore difficult to achieve. Much that can now be done is aimed at limiting further tooth wear in individuals already found to be affected by this condition. Population-based strategies of prevention, such as by widespread modification of the composition of soft drinks and educational campaigns to increase awareness of the causes of tooth wear may be possible but it is not likely that they will meet with the widespread acceptance that preventive strategies for caries have achieved. This is in part due to the age group perceived to be most at risk of developing erosion, teenagers and young adults, being rather resistant to the messages of health educators, at least when the message relates to reducing the consumption of erosive drinks that are so much a part of the lifestyle of this age group. More can possibly be done with an at-risk strategy aimed at specific individuals with early signs of tooth wear or with known risk factors for tooth wear present, such as those taking medicines known to be erosive and patients with bulimia. For such a strategy to work collaboration between the dentist and other healthcare professionals is important.

Preventive strategies

Strategies for preventing tooth wear are largely based on the individual. Abrasion and attrition are disorders that are individual-based. Erosion has certain features, including its prevalence and relationship to diet, that make the disease problem somewhat similar to that of caries. Few, if any, population-based strategies that have been so successful in caries prevention have, however, been shown to have an effect on erosion. The perceived increase in the prevalence of tooth erosion has produced an upsurge of research into possible ways of preventing erosion whereas other forms of tooth wear have received less attention.

Fluoride

Fluoride is the mainstay of caries prevention and it was, therefore, natural for fluoride to be considered as a possible vehicle for preventing tooth erosion. In fact the literature contains conflicting reports about the benefits of fluoride in this respect. A number of animal and in vitro studies suggest that adding fluoride to potentially erosive drinks will reduce the erosive potential of these drinks.29,30,31 Addition of fluoride to sports drinks has also been shown to reduce the erosive potential of these, otherwise highly erosive, drinks.32 Amaechi et al.,33 have shown that xylitol and fluoride have an additive effect in reducing the erosive potential of orange juice in in vitro studies. Larsen,34 however, showed that the protective effect against erosion of fluoride added to soft drinks was minimal. Clearly some more research is required in this area to resolve these differences, perhaps through the development of agreed test systems to evaluate erosive potential. It is known that tooth brushing shortly after drinking an erosive beverage causes an increase in tooth wear. Topical fluoride appears to protect against this subsequent tooth wear following acid challenge.35,36,37 This is especially helpful in reducing dentine wear in previously eroded teeth.38 Fluoride, therefore, appears to have only a limited protective effect against erosive challenge in vivo (Type 4).

Drink modification

Drink modification has been developing in recent years with varying success.30 Addition of calcium lactate to Coca Cola® has been shown to reduce the erosive potential of this most international of erosive beverages39 but this research does not appear to have been taken up by the manufacturer. Rather the reverse trend is seen with the marketing of drinks with added citric acid to drinks such as Pepsi Cola® and to several diet preparations of carbonated drinks. This increases the erosive potential of these drinks, at least when measured in vitro.40 A successful attempt to reduce the erosive potential of soft drinks by the addition of calcium citrate-malate was reviewed by Grenby30 but a later in vivo investigation by Rugg-Gunn et al.41 found no difference in the amount of erosion seen in enamel slabs treated with plain or modified orange drinks. One of the potentially most important steps in soft drink modification has been the development and subsequent marketing of Ribena Tooth Kind.42,43,44 This low pH blackcurrant drink has been modified with the addition of calcium and has been shown in in situ and in vitro studies to be less erosive than blackcurrant drinks without added calcium and also less erosive than orange juice. Considering the increasing prevalence of tooth erosion, especially in young children and teenagers and the strong association between consumption of acidic drinks and tooth erosion, it still seems logical to continue the development of drinks with low erosive potential. Drink modification has considerable potential in combating erosion but clinical trials are needed.

Diet modification is a difficult area in which to achieve successful disease prevention as experience from dental caries has shown. Nevertheless the strong links between dietary factors and tooth wear make it sensible for the dental team to at least try to get patients with tooth wear to modify their diet. Patients with tooth wear thought to be linked to dietary acids should be closely questioned about their dietary habits and modifications, suggested including reducing the frequency of consumption of these foods limiting consumption of fruit and fruit juices to mealtimes. Consuming hard cheese or milk products after drinking an erosive beverage may promote re-hardening of the enamel45,46 (Type 4). This is probably also a useful method of neutralising acid in the mouth after a bout of reflux or vomiting but patient compliance is perhaps questionable. Chewing-gum containing carbamide (urea) has been shown to raise salivary pH rapidly47 (Type 4). This may, therefore, reduce the erosive effect of acid in the mouth.

The pattern of drinking erosive beverages is thought to contribute to tooth erosion48 (Type 4) especially when cola-type drinks are swished around the mouth before swallowing. Drinking through a straw has been shown to reduce the potential for tooth erosion from acidic drinks49 (Type 4), especially on the palatal surfaces of the maxillary incisors that are most commonly affected in patients with erosion.

Abrasion caused by diet or tothbrushing is greater if the teeth have been recently exposed to dietary or gastric acid. It has been shown by Attin et al.50 that resistance to this abrasion develops in the mouth but that at least 60 min should elapse after an acid challenge to the teeth before brushing. This is probably of particular significance for patients who have frequent episodes of vomiting but it is also sensible for dentists to advise their patients not to brush shortly after consuming carbonated drinks. Similarly, mouthrinses with a low pH should not be recommended for prolonged use nor as pre-brushing rinses.51 Remineralizing toothpaste (Enamelon™) has been shown to increase the hardness of acid-treated teeth significantly more than conventional fluoride toothpastes in in vitro studies.52

Saliva and pellicle are important factors in protection of tooth substance against acid attack. Amaechi et al.33 and Johansson et al.47 have shown that erosion is usually found in areas of the dental arches that are lacking in pellicle. Increasing salivary flow and hence accumulation of pellicle will, therefore, probably offer protection against erosion. Data from clinical trials are lacking, however, although Hall et al.53 (Type 4) have demonstrated this protective effect of salivary pellicle in an in-situ model system. Increasing salivary flow and, consequently, buffer capacity should increase protection against erosion and promote remineralization. Sugar-free chewing gum and even fluoride-containing or carbamide-containing gum should be advised, particularly for adolescents who may be least willing to limit their consumption of acidic beverages. A number of preparations intended to promote salivation are available for patients including those with dry mouth symptoms who may not be willing to chew gum. Profylin™ (Prophylactor AB, Sweden) and Xerodent™ (Dumex-Alpharma, Denmark) lozenges are examples of such topical preparations and Xerodent™ has the added advantage of containing fluoride.

Gastric reflux

Reflux disease and vomiting are important causes of tooth erosion. Recognition of the erosion and presumptive diagnosis by the dentist should lead to appropriate referral for further investigation. Most often this will be to a gastroenterologist for gastroscopy and for 24-hour measurements of oesophageal pH. Medication to reduce gastric reflux and acid production includes drugs such as over-the-counter antacids or prescription drugs such as omeprazolum (Losec®) and ranitidinum (Asyran®). Should hiatus hernia be diagnosed then surgical intervention may be necessary. Diagnosis and treatment of the underlying condition is obviously a pre-requisite to stopping the progression of the tooth wear. In many cases of tooth wear associated with gastric disturbance, both attrition and erosion are seen. Because many individuals with erosion are young males, in our clinical experience at least, they are in the age group that is known to consume a lot of acidic drink but this is also the age group that is active in sport and training and may, for example experience gastric reflux as a consequence (Holbrook et al. unpublished findings, Type 4). Diagnosis of the tooth wear may be clear but determining the aetiological factors involved may, however, be difficult.54 Should the dentist believe that the patient may have bulimia then referral to a psychiatrist may be indicated. This is often difficult and depends to a great extent on the rapport and trust that the dentist has built up with the patient. At the very least the dentist should convey his suspicion to the patient's general medical practitioner. Careful monitoring of the progress of the tooth wear over time, for example with study casts, is helpful both for the dentist and as an aid to increase patient cooperation. The use of fluoride and antacid medications as well as the protective effect of cheese should be emphasised and careful instruction on tooth brushing technique to minimise abrasion should be given (Type 5).55

Lifestyle changes

Lifestyle changes are particularly difficult to achieve, especially in the age groups that are frequently found to have tooth wear. Drinking carbonated beverages with a straw; eating a piece of cheese shortly afterwards; and taking antacids,56 xylitol gum or xylitol-fluoride-containing lozenges57 after exercise are not activities that fit in particularly well with the lifestyle of young people. Nevertheless the dental profession has the responsibility to inform patients of the problem and its consequences. The success of fluoride in preventing dental caries in populations that continue to consume sugar at high levels is not likely to be repeated with tooth erosion. Indeed the rise in awareness of tooth erosion, in Europe at least, has occurred as caries levels have rapidly declined. Whether or not modification of acidic drinks to make them less erosive will prove possible or even acceptable to manufacturers and public alike remains to be seen. Considerable financial sums are at stake for the industry and it seems unlikely that these will be risked without public demand or legislation.

Restorative procedures

Restorative treatment of teeth affected by tooth wear is very expensive and not always covered by health services, even in Europe. There is also still a need for long-term studies on tooth wear, particularly into how erosion and related tooth wear progresses in young people. This makes authoritative recommendations on restorative measures impossible until further research has been completed. Various non-or minimally-invasive procedures have been tried in order to prevent further tooth wear but clearly extensive crown and bridge work is sometimes required. Lambrechts et al.58 have reviewed the various therapeutic approaches and point out that the durability of crown and bridgework is only 15–20 years which should be borne in mind in the light of the age group frequently presenting in the dental surgery with tooth wear. Conservative approaches that may also offer a degree of protection/prevention against further wear are therefore urgently sought as are restorative techniques that do not involve further destruction of remaining tooth substance. Dentine-bonding agents have been shown to be effective in reducing sensitivity and offering protection against further dissolution of erosive lesions59,60 (Type 3). These should be applied and the patient monitored before any final decision is taken on restorative measures.55

Prevention of attrition and abrasion is not usually considered until the patient actually has signs of the problem. Diagnosis is usually more straightforward than with erosion except in cases where attrition or abrasion are superimposed on erosion when diagnosis can become problematical. Patients with bruxism may well need occlusal splints, at least to use at night, and restorative treatment is frequently necessary. Correction of tooth brushing technique and the use of less abrasive toothpaste should help reduce abrasion and habits that may lead to abrasion should be controlled. As with tooth erosion it is helpful to make study casts and to monitor progression of the tooth wear.

Conclusion

A considerable increase in tooth wear has been observed in recent years. This is predominantly erosion though often complicated by other forms of tooth wear. Careful diagnosis and monitoring of progress are important and the underlying aetiological factors should be corrected wherever possible. The aetiology of tooth wear is often complex but individualised prevention can usually only be initiated once the disease has started. This is largely aimed at limiting progression of tooth wear in the affected individual. Population-based strategies are largely inappropriate in preventing tooth wear although modification of erosive drinks, medicines and foods may prove to be an acceptable future strategy for manufacturer and customer alike. Careful monitoring of patients following diagnosis of tooth wear, removal of causative factors and relatively simple dental treatments may enable the patient to avoid extensive restorative procedures.