From Volume 47, Issue 1, January 2020 | Pages 38-42
Looseness of dentures is a common complaint and can cause patients embarrassment and distress. Looseness is often associated with ill-fitting dentures, but some patients with technically excellent dentures may complain of looseness as a result of, for example, severely resorbed alveolar ridges, lack of saliva or poor adaptive ability. Recommendations for effective use of denture adhesive that can be given to patients by the dental team are provided.
Looseness of dentures can cause patients great embarrassment and distress. Looseness is often a result of ill-fitting dentures, but some patients have great difficulties controlling dentures that are technically excellent. Severely resorbed alveolar ridges and lack of saliva contribute to dentures being loose and lead to difficulty in keeping dentures in place. Even patients with good alveolar ridges and technically excellent dentures may complain of looseness because of poor adaptive ability.
Denture adhesives are widely available in supermarkets, pharmacies and online in a variety of forms and formulations (Figure 1). Denture adhesives have potential benefits but also potential adverse effects. It is important that the dental team can provide patients with advice on their correct use.
This article describes denture adhesives and discusses recommendations for their use that can be made to patients by the dental team.
Denture adhesives can be considered in two broad groups:
A review of the effectiveness of denture adhesives concluded that many studies have shown that the use of a denture adhesive can improve retention and stability of dentures and that masticatory function can be improved.1 Adhesives also provide a seal that prevents food particles from entering under the denture.2
It has been shown that patients with good or poor denture-bearing tissues can benefit from the use of adhesives, though the effect is more significant for denture-wearers with poor denture-bearing tissues. Strips are least effective.3,4
The effects of application of the different types of adhesive fixatives vary considerably.1 The duration of improved retention varies between 3 and 12 hours. The duration of effect in the maxilla is generally greater than that in the mandible.
Whilst the powder adhesive is effective shortly after its application, retentive forces with the cream and paste materials may not peak until as much as 3 hours after application. Powder fixatives lose their effectiveness more rapidly because of the rapid solution of the active ingredients by saliva. Creams absorb moisture from the mouth more slowly and therefore they hold over a longer period.
Denture adhesive that is lost from the denture surface will be swallowed. None of the constituents of modern denture adhesives, besides zinc discussed below, is believed to be potentially harmful.
Some formulations of denture adhesives contain zinc compounds in order to enhance properties. Zinc is an essential mineral found in a range of foodstuffs. However, long-term excessive ingestion of zinc can result in hypocupremia, a copper deficiency. Hypocupremia is toxic to the nervous system and can cause progressive irreversible neuropathy, with symptoms including paresthesia, muscle weakness and ataxic gait. Chronic overuse of zinc containing denture adhesives has resulted in such cases.5 At least one manufacturer withdrew zinc-containing formulations (Polygrip, GlaxoSmithKline, Brentford, Middlesex, UK). There is no evidence, however, that zinc-containing denture adhesives are harmful when used according to manufacturers' instructions. Zinc-free denture adhesive formulations are readily available. The information about zinc content is provided on the product packaging. Zinc-free products often have this information displayed prominently.
In vitro studies suggest that denture adhesives can have an irritant effect on the tissues of the oral mucosa.6,7 Regular use of denture adhesive has not been shown to be associated with any increased incidence of mucosal irritation.8
In vitro studies have demonstrated microbial contamination and growth in some denture adhesives.9,10 Concern has also been expressed about the potential for fixatives to support growth of micro-organisms. Denture adhesives were not shown to increase growth of oral micro-organisms clinically in healthy patients.11 There are, however, no clinical studies of the effect of adhesives on the mucosa over a period of greater than six months. It has been suggested that fixatives should not be used by immunocompromised patients.
There are no recent reports of allergy to any commercially available denture adhesives. However, several of the components of denture adhesive are potential allergens. It would be prudent to take any case of potential allergy seriously.
Anaesthetists routinely request that patients remove dentures prior to general anaesthesia to prevent potential airway obstruction. In that regard, there have been cases where residual denture adhesive has caused adherence of soft tissues and temporary airway obstruction during intubation and recovery.12,13
The choice of a type of adhesive appears to depend on individual user preference in respect of product taste, texture, performance and cost. It can be a good idea, therefore, for patients to experiment and choose the product they find suits them best. Manufacturers' instructions should always be followed when applying the adhesive. General principles of application are given in Table 1.
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Having removed dentures before sleeping, the denture adhesive should be removed from the denture surface by brushing with a soft brush and warm water before the dentures are cleaned in the usual manner.14,15 Patients should be warned of the risk of residual denture adhesive remaining on the oral mucosa once their dentures have been removed and advised to remove the residual material using a clean damp cloth or soft toothbrush.
It has been suggested that to recommend the use of denture adhesives is a sign of failure on the part of the dentist. It is true that not all denture-wearing patients need or want to use an adhesive. Many patients, however, report looseness with or without good supporting tissues yet have excellent dentures. Several groups of denture-wearers can benefit from the use of adhesives:
Adhesives can improve denture retention, bite force and masticatory function. They can help patients adapt to dentures.
Because denture adhesives come in various forms and have potential benefits and harmful effects, it is important that the dental team can provide patients with advice on their correct use, including how to clean the denture and mucosa following use. It is good practice also to provide patients with written information such as shown in Tables 1 and 2.
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The potential harmful effects from the use of denture adhesives include mucosal irritation, microbial contamination, neurologic defects and allergic reactions. However, there is no evidence that harm is done by long-term use of fixatives when used sparingly and according to manufacturers' instructions, but it is sensible to recommend that as little adhesive as possible is used. It has been suggested that fixatives should not be used by immuno-compromised patients.
Adhesives should not be used to compensate for poorly fitting dentures. Dentists should provide advice to patients regarding improvement or replacement of dentures that do not fit.
It is true that not all denture-wearing patients need or want to use an adhesive. Far from the use of denture adhesives being a sign of failure on the part of the dentist, this article has described several groups of denture-wearers who might benefit from the use of adhesives and has described recommendations that members of the dental team may give to their patients.
