Tooth Erosion

Erosion may present on the anterior and posterior teeth and may be limited to the enamel only (Figure 1) or also affect dentine to a greater or lesser extent. Frequently, erosion is seen affecting the palatal surfaces of four maxillary incisor teeth. Erosion in the molar and premolar teeth may present as dishlike depressions on the occlusal surfaces, usually extending into dentine. If teeth have been restored prior to erosion occurring, the restorations stand proud of the surrounding enamel (Fig. 2). There may be a loss of vertical dimension and, particularly, 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. This pattern 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, especially if the enamel has also been lost on these surfaces. Erosion in the maxillary anterior teeth may be so severe that it extends close to, or even into, the pulp. Rapidly progressing erosion may cause hypersensitivity of the teeth but commonly the progress is too slow for symptoms to arise. Nevertheless, patients may complain of discomfort in their teeth during eating or drinking and of increased sensitivity to cold stimulation.

Lesions of erosion are first detectable as a loss of enamel lustre and a matt appearance of the enamel. This progresses to clearly detectable loss of tooth substance in the enamel and then in the dentine as described above and shown in the figures. If the thinning of the maxillary anterior teeth is sufficiently great, fracture of the unsupported incisal edges may occur (Fig. 3). Erosion usually progresses quickly in dentine when other types of tooth wear become superimposed on the erosion.

In recent years the high consumption of soft drinks has been the aetiological agent that has been most implicated in the upsurge of tooth erosion that has been reported particularly from Europe. Although a low salivary buffer capacity may exacerbate the effects of these acidic drinks on teeth, there is conflicting evidence in the literature concerning the contribution of a low buffer capacity to the severity or progression of erosion. It would seem logical to assume that a low buffer capacity would at least extend the time during which tooth enamel was eroded after contact with an acidic drink. Swishing a drink around in the mouth appears to increase the severity of erosion while drinking through a straw reduces the severity of erosion. Although much attention has been placed in recent years on the role of extrinsic acids, mostly from foods but also from medicines and the workplace in the causation of erosion, intrinsic acid in the form of refluxed gastric acid is still a major aetiological factor in tooth erosion. Scanning electronmicrographic appearances of eroded enamel and dentine are shown in Fig. 4 and Fig.5 respectively.

Restorative treatment of teeth affected by tooth erosion is often complex and very expensive, especially if occlusal erosion has caused a significant reduction in vertical dimension. As there are few long-term studies on how tooth erosion and related tooth wear progresses in young people, recommendations on restorative measures are difficult to make. 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. As the durability of crown and bridgework is limited and patients with erosion are often young, conservative approaches that may also offer a degree of protection or prevention against further wear are therefore urgently needed. Restorative techniques should preferably involve no 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 lesions. These should be applied and the patient monitored before any final decision is taken on restorative measures.

With the high prevalence of tooth erosion recorded in some surveys, tooth erosion has now achieved the status of a community-wide dental problem in several countries. Nevertheless, true prevention is difficult to achieve. Much that can be done is aimed at limiting further erosion in individuals already found to be affected by this condition. Population-based strategies of prevention, such as widespread modification of the composition of soft drinks and educational campaigns to increase awareness of the causes of tooth wear may be possible. The groups most at risk of developing erosion are, however, teenagers and young adults, and these are 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 their lifestyle. More can possibly be done with an at-risk strategy aimed at specific individuals with early signs of erosion or with known risk factors for erosion, such as those taking erosive medicines and patients with bulimia. For such a strategy to work collaboration between the dentist and other health-care professionals is important. Topical fluoride, the mainstay of caries prevention, appears to protect against abrasion following acid challenge but has no direct effect in preventing erosion. Drink modification has been developing in recent years with varying success. Calcium lactate has been shown to reduce the erosive potential of to Coca Cola® but this research does not appear to have been taken up by the manufacturer. The addition of calcium to low pH fruit drinks has been shown in in-situ and in-vitro studies to be less erosive than the same drinks without added calcium. 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. Nevertheless the strong links between dietary factors and tooth erosion make it sensible for the dental team to at least try to get patients with tooth wear to modify their diet. Consuming cheese or milk products after drinking an erosive beverage may promote re-hardening of the enamel. 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 rapidly. This may, therefore, reduce the erosive effect of acid in the mouth.

The pattern of drinking erosive beverages is thought to contribute to tooth erosion 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 drinks, especially on the palatal surfaces of the maxillary incisors that are most commonly affected in patients with erosion.

Dentists should advise their patients not to brush shortly after consuming carbonated drinks as this may increase loss of enamel. Similarly, mouth rinses with a low pH should not be recommended for prolonged use nor as pre-brushing rinses. Remineralizing toothpaste has been shown to increase the hardness of acid-treated teeth significantly more than conventional fluoride toothpastes in in-vitro studies.

Saliva and pellicle are important factors in protection of tooth substance against acid attack. Studies have shown that erosion is usually found in areas of the dental arches that are lacking in pellicle. Increasing salivary flow will lead to greater accumulation of pellicle as well as increasing the buffering action of saliva and, consequently, will promote remineralization. Sugar-free chewing gum, fluoridecontaining 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.

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. Medication to reduce gastric reflux and acid production includes drugs such as over-the-counter antacids or prescription drugs such as omeprazole (Losec®), esomeprazole (NexiumÆÊ) and ranitide (Asyran®). Antacids may help and they may be kept in the mouth for a while before swallowing for a local buffering effect. Should hiatus hernia be diagnosed then surgical intervention may be necessary.