This study will examine the types of bacteria present in the dental plaque of patients with persistent dry mouth. Saliva is essential for digestion and swallowing and for maintaining the normal mineralization of teeth. People who suffer from dry mouth usually have a significant increase in tooth decay (caries). This study will determine if this increase is due solely to reduced salivary flow or also to an increase in certain types of bacteria in the mouth.

Patients participating in the following NIDCR protocols may be eligible for this study: Evaluation and Treatment of Salivary Dysfunction (84-D-0056), Natural History of Salivary Gland Dysfunction and Sjogren's Syndrome Research Project (99-D-0070), and Salivary Evaluation in Normal Volunteers (94-D-0018).

Participants will have three appointments at the NIH dental clinic as follows:

Visit 1

Dental examination and instruction on keeping a detailed diary of food intake.

Visit 2 (1 week after visit 1)

Attachment of a bacteria collection device (described below) to the side of a tooth.

Visit 3 (48 hours after visit 2)

Removal of the collection device, tooth cleaning and polishing, and submission of food diary.

The bacteria collection device is a 4mm x 2mm x 2mm square of sterilized tooth obtained from slicing an extracted healthy tooth donated by another patient. The donated teeth are either extracted impacted third molars (wisdom teeth) or teeth extracted for teeth straightening (orthodontics). The device is heat-sterilized before being bonded to the participant's tooth. The dental cement used for bonding can be removed after 48 hours with no damage to the surface of the participant's tooth.