Prevention and Control of Dental Erosion: Professional Clinic Care

Fig. 9.1

Very early stages of uncontrolled erosion in a 22-year-old patient. Teeth affected include the labial cervical third of 13, 12, 11, 21, 22 and 23. Remineralizing procedures can repair softened enamel but the ‘dished-out’ appearance will remain (i.e. the enamel rods will not grow back). Prophylactic coverings over the affected surfaces can protect the teeth until management of the acid source is achieved
In cases where the saliva is compromised (e.g. Sjogren’s syndrome), automatic repair from saliva after the acid challenge will be ineffective. Therefore, in such cases, the clinical preventive approach should aim to provide the appropriate concentrations of ions (e.g. calcium, phosphate) in the oral environment, replacing what is lost from saliva.
There is now a strong argument to also consider ‘fostering’ and utilizing the pellicle/biofilm wherever possible in the management of erosion [5]. Apart from providing a physical barrier to acid, biofilm also provides a ‘closed system’ where ions from saliva and from professionally applied products provide supersaturated conditions for remineralization.
At the other extreme, the main problem with uncontrolled, very active erosion is that the many acids (in particular soft drinks and gastric acid) have a pH well below the critical pH of hydroxyapatite and fluorapatite. Irrespective of how well enamel is repaired by remineralizing products, the next acid episode will bring about gross dissolution. Although in vitro studies have repeatedly shown that the remineralizing effects of saliva and indeed remineralizing products with fluoride can repair a softened surface and make it more resistant to further acid attack, it is difficult to translate this in vitro research to the clinical situation. In reality, the extent of clinical protection provided by remineralization in uncontrolled cases is at best minimal. In these cases, the total mineral loss is more than the total mineral gain, making management of these cases difficult.
Based on clinical experience, uncontrolled active erosive cases cannot be contained by remineralizing products alone, even in the presence of good quality saliva. The preventive management in these cases requires protective surface coatings to be placed over the affected areas to prevent acid from reaching the tooth [11]. In addition, prophylactic barriers that also have the potential to remineralize would, by inference, be more beneficial. Either way, these patients must be made aware that this approach requires regular maintenance due to the breakdown of these barriers over time. Until most prophylactic barriers are ‘purpose-made’ by manufacturers to endure mechanical and erosive environments at least as well as most restorations, the majority should currently be considered as ‘sacrificial’ and transient tooth tissue prophylactic agents.
Finally, prophylactic coverings placed on eroded areas have the added advantage of immediately eliminating hypersensitivity by instantly obturating patent dentinal tubules. This is an added advantage when the patient’s chief complaint is pain.

9.3 Remineralization Methods for Softened Tooth Surfaces

The professionally applied products discussed below are not presented in any order of preference nor is the effectiveness of the products or techniques compared. They are listed as possible approaches to remineralization that are available to clinicians and should be used in conjunction with home preventive measures.
Traditionally, fluorides in the form of gels and foams have been used and are still being used for the remineralization of softened enamel and for slowing the demineralization process. However, fluoride is only effective when other elements (e.g. calcium and phosphate ions) also co-exist in the correct proportions to produce effective remineralization. Therefore, fluoride applied professionally in high concentrations on newly eroded surfaces will remineralize by utilizing the existing calcium and phosphate in saliva, after which the excess fluoride is expectorated or ingested and therefore wasted. In order to overcome this, a number of approaches can be considered, either individually or in combination.
Extending the physical presence of fluoride can be achieved if it is applied in the presence of biofilm. Here the fluoride is ‘held’ within the biofilm and when the pH drops during a subsequent acid challenge, it is allowed to combine with calcium and phosphate from saliva. Normally, calcium ions in saliva are complexed with statherins and proline-rich proteins and will not become available unless there is a drop in pH during an acid attack. This can occur in milder erosive cases where some biofilm/pellicle is most likely to form between episodes of acid challenge. This also supports the premise that a prophylaxis should not be done before preventive measures.
The use of fluoride varnishes can also extend the physical presence of fluoride by allowing more time for the accumulation and increasing concentration of calcium and phosphate ions from saliva to utilize the excess fluoride. Although this method provides more effective remineralization, excess fluoride is still wasted. In addition, excess fluoride can be utilized when applied in high concentrations if comparable high concentrations of bio-available calcium and phosphate are also added to the oral environment, as with the various calcium-phosphate technologies available today.
Opinions vary as to which fluoride concentrations are ideal for erosion. Inferences are often derived from past research relating to caries indicating that low but sustained concentrations of fluoride seem to provide resistance to demineralization and more effective remineralization [12, 13]. However, more recent evidence indicates that for erosion, higher concentrations seem more effective especially if polyvalent fluoride formulations (e.g. stannous fluorides, silver fluoride) are used. In particular, an increase of metal ion to fluoride ratio (e.g. stannous to fluoride ratio) seems more effective [14]. Finally, the effective relevance of a ‘one-off’ professional application alone is limited; however, when coupled with continuous home applications, the positive effects become long term and more effective.

9.3.1 Professionally Applied Fluorides

9.3.1.1 Gels and Foams

Professionally applied fluorides are usually high concentration neutral Fluorides (e.g. 2 % NaF) that can be easily dispensed in disposable trays as either gels or foams (Table 9.1). Although foams require less material than gels to supply the same amount of fluoride, much of the fluoride benefit from these high concentrations is limited by the concentration and availability of calcium and phosphate.

Table 9.1

Examples of products that can be used professionally for the prevention and control of dental erosion
Generic product
Name
Details
Company
Neutral fluoride
Denti-Care Pro-Foam
Denti-Care Pro-Gel
2 % neutral sodium fluoride foam
2 % neutral sodium fluoride gel
Medicare (US), (CAN)
Nupro Neutral Fluoride Gel
2 % neutral sodium fluoride
Dentsply (AUS)
Neutra Foam
2 % neutral sodium fluoride
Oral B (US)
Neutracare Gel
1.1 % sodium fluoride
Oral B (US)
APF
Nupro Acidulated Phosphate Fluoride Foam
1.23 % APF
Dentsply
Floam
1.23 % APF
Germiphene
Ultra Control Foam
1.23 % APF
Waterpik (UK) (EUR)
One minute topical Fluoride Foam
1.23 % APF
Laclede (US), (AUS)
Stannous fluorides
Pro Health Toothpastes
1450 ppm F (stabilized stannous fluoride 1100 ppm, 350 ppm sodium fluoride and sodium hexametaphosphate)
Oral B (AUS)
Crest Pro Health Toothpastes
0.454 % stannous fluoride
Crest (US)
Gel Kam
1000 ppm stannous fluoride
Colgate (AUS)
Fluorigard Gel Toothpaste
1000 ppm stannous fluoride
Colgate (AUS)
Fluoride varnishes
Duraphat
Sodium fluoride varnish
22, 600 ppm fluoride
Colgate (AUS)
Cavity Shield
5 % sodium fluoride varnish
3 M (US)
Profluorid Varnish
5 % sodium fluoride varnish
Voco (UK), (USA), (AUS)
DuraShield Varnish
5 % sodium fluoride varnish
Sultan Healthcare (EUR), (CAN), (US)
Nupro
5 % sodium fluoride varnish
Dentsply International
CPP-ACP
Tooth Mousse
Creme
GC (AUS), (EUR)
Tooth Mousse Plus (containing fluoride)
Creme
GC (AUS), (EUR)
MI Paste
Creme
GC (US)
MI Paste Plus (containing fluoride)
Creme
GC (US)
MI Varnish
5 % sodium fluoride varnish with recaldent
GC (US)
TCP
Clinpro White Varnish
5 % sodium fluoride with Tri-Calcium Phosphate
3 M ESPE (AUS), (EUR)
Vanish Varnish
5 % sodium fluoride with tri-calcium phosphate
3 M ESPE (US)
Clinpro Tooth Crème (toothpaste)
950 ppm fluoride with TCP
3 M ESPE (AUS), (EUR)
ACP
Enamel Pro Varnish
5 % sodium fluoride with ACP
Premier (US)
Traditional prophylaxis of teeth before application of these products is not recommended and application of fluoride should occur after the biofilm is allowed to form. Late afternoon appointments, or preferably asking the patient not to brush on the day of the appointment, have benefits. However, asking patients not to brush should occur with selected, dentally aware patients otherwise the wrong message will be sent about oral hygiene and oral health.
Directions for fluoride gels and foams:

  • Prophylaxis is not recommended.
  • Close-fitting trays should be used (these can be constructed by thermoforming machines that heat and mold silicone blanks onto patient’s casts). The amount of fluoride dispensed should only cover the tray surface rather than filling the trays completely. Each tray should not exceed 2 ml in total.
  • The duration of the application should be about 4 min with the excess expectorated for about 30 s after the trays are removed. A salivary ejector should be used during the procedure.
  • Finally, the patient is advised not to eat or drink for 30 min after application.
Operators must be aware not to exceed the ‘probable toxic dose’ measure of 5 mg/kg for fluoride of body weight per day, and age recommendations must be adhered to. High concentration gels are not recommended for children younger than 10 years of age because of the potential of ingestion.
Acidulated Phosphate Fluoride (APF) gels are also high concentration fluorides (1.23 % fluoride) that are recommended by some clinicians (Table 9.1). In vitro studies have shown that APF provides more protection than high concentration NaF gels in both endogenous erosion and particularly in wine tasters erosion where the acidic challenge is extreme [11, 15]. For example, the use of APF with professional wine tasters has shown a high degree of protection especially when biofilm is allowed to establish for at least 24 hours before a wine tasting event. Professional application of APF the day before the tasting and supplemented periodically by patient-applied home preventive care is very effective. In addition, acidified fluoride gels over erosion lesions seem to show higher abrasion resistance than neutral fluorides [16].
Although the pH of APF is about 3.0–3.5 and may not seem appropriate for erosive cases, there are some benefits when saliva is compromised. Here, the low pH of the APF demineralizes the tooth surface, allowing calcium ions from the tooth to be used with the phosphate and fluoride ions in the APF for remineralization. Again, close-fitting-trays are recommended and post-application instructions are similar to those described above. However, the low pH of the product is contra-indicated in patients who have teeth restored with glass ionomer cements and with indirect ceramic restorations.
Directions for APF:

  • Prophylaxis of the teeth is not recommended.
  • The gel should be wiped into ‘thermo-formed’ close-fitting trays (as described above) and applied for 1 min.
  • The excess is expectorated for 30 s after the trays are removed. A salivary ejector should be used during the procedure.
  • Do not eat or drink for 30 min after application.
In vitro studies have consistently shown that bivalent metal-ion fluorides, such as Stannous Fluoride (SnF 2 ) (Table 9.1), can protect tooth surfaces from acid attack. Although it has been attributed to the remineralization effects of fluoride, in reality these products provide their effect by the deposition of stannous fluorophosphate (and stannous oxide) precipitate on the tooth surface that is highly insoluble to acid. This occurs when stannous attaches to free phosphate sites on the enamel surface. This precipitate is also effective in obturating patent dentinal tubules, thereby eliminating hypersensitivity.
Where the stannous products are presented as toothpastes (e.g. ProHealth products), they can be used professionally as prophylaxis pastes, and where they are available as gels (e.g. Gel-Kam) they can be used professionally (similar to the gels described above) in closely fitting trays to ensure complete coverage (even though most gels are applied with a finger or toothbrush during home application).

9.3.1.2 Fluoride Varnishes

Extending the physical presence of fluoride can also occur when the fluoride is used as a varnish (Table 9.1). Varnishes are high-concentration fluorides (e.g. 5 %) that provide more effective remineralization because of superior ‘contact time’, allowing more calcium and phosphate from saliva to be utilized due to a longer period of salivary flow. Unused or excess fluoride is still discarded by swallowing. There are differences of opinion about the use of fluoride varnish. Professionally directed spot application onto very active and affected areas, supplemented with home fluoride use, seems a common approach, while other operators recommend complete coverage. Although the positive effects of these fluorides are based on research with high caries risk patients, evidence on their effects on erosion is slowly becoming clearer. Within an erosive environment, varnishes on their own are effective in erosive wear (i.e. combination of acid and mechanical action) [17]; however their long-term effect seems uncertain and should be supplemented with a home preventive program.
Directions for varnish application:

  • Prophylaxis of the teeth is not recommended.
  • Varnish is applied manually with a finger or brush after the mouth is dried, using gauze, cotton rolls and air. It sets when in contact with saliva.
  • The patient is advised not to eat or drink for 30 min after application and should not brush until the following day.
  • There are no current reliable clinical data indicating the number of required applications per year for erosion.
Although the fluoride content of varnishes is traditionally high, the amount ingested when compared to high concentration gels and foams is comparatively low because of the slow fluoride release, making it preferable for younger children below 10 years of age.

9.3.2 Professionally Applied Calcium-Containing Technologies

Products with all the components required for the remineralization of teeth have definite benefits; however, the biggest obstacle that had to be overcome by manufacturers was to keep highly reactive calcium, phosphate and fluoride ions apart and prevent them from precipitating during storage, yet make them bio-available when applied in the oral environment. The general approach taken by manufacturers mimics saliva where statherins and proline-rich proteins naturally stabilize calcium, preventing precipitation, yet allowing the ions to become bio-available when the pH drops in the oral environment. There are a number of different technologies that allow this to happen and the main ones include Recaldent (CPP-ACP) technology, Tri-calcium phosphate (TCP) technology and other types of amorphous calcium phosphate (ACP) technologies.

9.3.2.1 Recaldent (CPP-ACP) Technology

One group of products that include calcium and phosphate for remineralization are those with the Recaldent technology (i.e. CPP-ACP: casein phosphopeptide – amorphous calcium phosphate). Here the calcium is stabilized by the protein CPP, preventing precipitation during storage within the dispensing tube. After application, when the oral pH drops during an acid challenge, the calcium is released from the CPP providing supersaturated conditions and therefore remineralization [18

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Nov 30, 2015 | Posted by in General Dentistry | Comments Off on Prevention and Control of Dental Erosion: Professional Clinic Care
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