Source: Medscape Today

December 28, 2011 — There is not enough evidence to recommend any topical therapies for dry mouth, but that does not mean that they do not work, according to investigators who published a review of research on the therapies online December 4 in the Cochrane Library.

“There was very little evidence,” said Helen Worthington, PhD, a professor of evidence-based care at the University of Manchester, United Kingdom.

Dr. Worthington and colleagues scoured the literature for randomized controlled trials of topical therapies for dry mouth, or xerostomia. They found 36 studies of treatments such as lozenges, sprays, mouth rinses, gels, oils, chewing gum, and toothpaste.

Xerostomia often results from treatments for head and neck cancer that damage the salivary glands, as well as from Sjögren’s syndrome, an autoimmune disorder that also damages these glands. It is also a common adverse effect of many medications.

The authors cite an estimated prevalence of dry mouth of about 20% in the general population. This percentage may be increasing because people are living longer and suffering from more chronic illnesses for which the treatments can have xerostomia as an adverse effect.

It is possible to feel the sensation of dry mouth without having a clinically reduced saliva flow, the researchers point out.

The treatments in the review broke down into 2 broad categories: saliva substitutes, in which some other substance is intended to perform the role of the patient’s own saliva, and saliva stimulants, which are intended to activate the patient’s own mechanism for producing saliva.

Two of the trials compared saliva stimulants with placebos, 9 compared saliva substitutes with placebos, 5 compared saliva stimulants with saliva substitutes, 18 compared 2 or more saliva substitutes with each other, and 2 compared 2 or more saliva stimulants with each other.

The researchers found convincing evidence that 1 saliva substitute, oxygenated glycerol triester saliva spray, was more effective than another, an electrolyte spray (standardized mean difference, 0.77; 95% confidence interval, 0.38 – 1.15). This corresponded to an approximate mean difference of 2 points on a 10-point visual analog scale in which patients rate their mouth dryness.

However, this evidence did not actually prove that either substitute was useful for treating dry mouth, Dr. Worthington said.

The researchers concluded that an integrated mouth care system (toothpaste, gel, and mouthwash) looked promising, as did oral reservoir devices. Here again, however, the evidence was not quite strong enough to recommend either one.

Asked to comment on the review, Joel Napeñas, DDS, a specialist in saliva disorders at Carolinas Medical Center in Charlotte, North Carolina, told Medscape Medical News that it is still possible to treat dry mouth despite the lack of evidence for a particular therapy.

“There are a lot of nonrandomized controlled trials that do show variable results,” said Dr. Napeñas, who was not involved in the Cochrane review. “Since there is no strong evidence for any individual agent, we are left with trial and error on an individualized basis.”

Dr. Napeñas begins by measuring saliva flow: He has the patient spit into a cup and then asks the patient to suck on something like a piece of wax and spit again to see whether the sucking action increases the patient’s saliva flow.

If the saliva flow increases, this suggests that saliva stimulants may work. Barring contraindications, therefore, Dr. Napeñas prescribes systemic saliva stimulants, usually pilocarpine or cevimeline, often in combination with topical stimulants.

If the experiment does not increase saliva flow, Dr. Napeñas instead recommends various saliva substitutes. He also typically recommends that patients try a variety of topical therapies to see what works best. “Biotene-type products are some of the first we would go to,” he said.

Frequently sipping water and sucking on ice can help many patients, he said. He advises patients to avoid caffeine and alcohol, which can worsen symptoms, and he pointed out that patients with xerostomia should avoid many commercial mouth rinses because they contain alcohol.

Dr. Napeñas also initiates preventive measures to prevent caries, including topical fluoride, prescription fluoride products, and frequent recalls, because patients with low saliva flow are at high risk for caries.

“It’s a very difficult condition to treat,” he said. “The way I approach it is to throw everything I can at it.”

This news story was resourced by the Oral Cancer Foundation, and vetted for appropriateness and accuracy.

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