Saliva changes in Parkinson's disease patients after injection of Botulinum neurotoxin type A.

Patients with Parkinson's disease (PD) are compromised by poor oral condition due to oropharyngeal bradykinesia, dysphagia, and the side effects of treatment. Intrasalivary gland injections of Botulinum neurotoxin type A (BNT-A) have been known to treat sialorrhea effectively in these patients. However, the decreased amount of saliva reduces self-cleaning ability that deteriorates oral hygiene and increases dental caries. The aim of this study was to determine the changes in the oral microflora and saliva in patients with PD treated for sialorrhea by means of sonography-controlled BNT-A injections into the bilateral parotid and submandibular glands. Altogether, 38 persons participated in the study: 12 PD patients who were injected with BNT-A for treatment of sialorrhea and passed salivary tests before and 1 month after the injections; and 13 PD patients and 13 healthy subjects who were not injected with BNT-A and passed salivary tests once. The condition of oral health was measured by the amount of saliva, salivary flow rate, and salivary composition. A good outcome with a significant decrease in salivary flow rate occurred at 1-month follow-up in the BNT-A-treated group while no significant change was found in salivary composition. BNT-A treatment did not change the Streptococcus mutans levels in saliva but there was statistically significant increase in levels of Lactobacilli. BNT-A injections can effectively treat sialorrhea while considering the change of oral microflora, and the patients should be under dentists' care more frequently. EudraCT clinical trial number: 2015-000682-30.