Dental CPD Australia

Components of Denture Adhesives

The early denture adhesive products were mainly composed of vegetable gum, such as Karaya, Tragacanth, Xanthan and Acacia. These gum-based products showed average, non-ionic adhesion to the tissue surface of the prosthesis and mucosal surface and would therefore provide little cohesive strength. Other unsatisfactory properties may be highly water soluble and patients have shown allergic reactions, particularly to Karaya.

These days, denture adhesives made from synthetic materials dominate the market. The main components being Carboxymethyl cellulose (CMC) and Polyvinyl methyl ether maleate (Gantrez). CMC are the short-acting components that hydrate in water and cause a quick-onset ionic adhesion to both the tissue surface of the prosthesis and the mucosal surface. This also causes the increase in viscosity of saliva and eliminates voids as it increases in volume. Polyvinylpyrolidone (povidone) is a component that can be used like CMC but is less common. Gantrez are the long-acting components that hydrate and increase adherence and viscosity over a longer period of time than it would take for CMC. These long-acting gantrez salts are less soluble and have molecular cross-linkings that increase cohesion. Gantrez formulations may be of a calcium-zinc gantrez or a calcium-sodium gantrez, but calcium-sodium gantrez have a less cohesive effect.

Other cream type denture adhesives may include Petrolatum, Polyethylene oxide and mineral oil that are used as binding for the different components. Powder type denture adhesives may have Silicone Dioxide and Calcium Stearate that are used to minimize clumping of the powder. Menthol and peppermint oils are used for flavoring, while red dye is used for color. Sodium borate and methyl- or poly- paraben are used as preservatives.

Types of Denture Adhesives and How to Use Them

Denture adhesives are either soluble or insoluble. Currently, the better of the two, due to less adverse effects, is the soluble forms that are marketed as creams (paste), powders, or wafers/strips. The insoluble denture adhesives are the cushions and do-it-yourself reliners. Insolubles are less recommended, due to adverse effects speculated with their use including oral tissue irritation, changing occlusal relations, changing vertical dimension and excessive bone resorption. Dental education professionals should note that scientific evidence is still sparse regarding the use and effects of insoluble denture adhesives and these claims are solely based on clinical observations.

Cream or paste denture adhesives are smoothed out or dotted along the tissue surface of the completely cleaned and dried appliance. They work like a glue, providing a high level of suction between the denture and oral mucosa. Manufacturers usually recommend that thin beads of the adhesive be placed in the anterior and posterior areas. Some would recommend placement of small drops at 5mm intervals for a more even distribution. After placement of the adhesive, the denture is immediately firmly seated inside the moist mouth.

Powdered denture adhesives combine with saliva to form a paste in the mouth. They are thinly and evenly sprayed or scattered onto the tissue surface of the cleaned and slightly moistened appliance. Excess powder should be removed by shaking to avoid getting the substance in other areas of the mouth. Seat the denture firmly in place ensuring the mouth is moist prior to insertion. Powder adhesives can be used in smaller quantities and are easier to clean from the denture, however they do not provide as much retention as cream type adhesives. Equally they do not last as long in the mouth due to being more soluble.

Wafers and strips are similar is use. Both wafer and strips are used by placing the sheets to cover the tissue-surface and then seating the denture in place with light force. Separate sheets are needed for the maxillary and mandibular denture. These are the newest forms of denture adhesives available.

When using denture adhesives, the patient must remember that "less is more". Increasing the amount of denture adhesive, may actually decrease its retention properties because there will be a thicker material that pushes the prosthesis away from the oral mucosa rather than bringing it closer. Remember to inform patients that the manufacturer's recommendation for use should be followed.

Patients must also be reminded that placement of adhesive is done only once a day and that the denture must be thoroughly cleaned before and after placement of an adhesive. Advice your patient on the correct cleaning procedure and application and never assume they know. Patients must also be instructed to remove all adhesives within the mouth by rinsing with warm water and wiping the alveolar ridges and palate with wet gauze or washcloth. Accumulation of adhesive in the oral cavity and prosthesis increases the risk of bacterial and fungal infections, therefore the importance of cleaning and good oral hygiene is essential.

When choosing which type of denture adhesive to use, the decision should be made by the patient depending on which is easiest to apply and clean, most comfortable, and that which satisfies the patient's expectations for retention. it is advised to inform the patient of the different types of denture adhesives so the patient can make an educated decision.

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