Xerostomia, Sialadenitis, Sialolithiasis: Practical Guide

Saliva keeps the mouth comfortable, helps us taste and swallow, and protects the teeth from decay. When the salivary glands fail, three common problems appear: xerostomia (the feeling of dry mouth), sialadenitis (infection and inflammation of a salivary gland), and sialolithiasis (a stone blocking a salivary duct).

These conditions matter because chronic dry mouth rapidly causes tooth decay and gum disease, a swollen infected gland can become a medical emergency, and a blocked duct causes sharp pain every mealtime. Understanding each one leads to the right test and the right treatment.

Key Concepts

• Xerostomia is the subjective complaint of dry mouth. It usually reflects hyposalivation (low saliva flow): normal unstimulated flow is about 0.3–0.4 mL per minute, and below 0.1 mL per minute is clearly abnormal.
• Sialadenitis is inflammation of a salivary gland, most often bacterial (commonly Staphylococcus aureus) or viral, as in mumps. The gland becomes swollen, red, tender, and pus may appear at the duct opening.
• Sialolithiasis is a calcified stone in a salivary duct. About 80–90 percent of stones form in the submandibular gland (Wharton's duct), because its saliva is thicker and flows uphill against gravity.
• Common causes of dry mouth: medicines (antidepressants, antihistamines, blood-pressure drugs), Sjögren's syndrome (an autoimmune attack on glands), head-and-neck radiotherapy, diabetes and simple dehydration.

How It Works

1. Xerostomia: drugs that block nerve signals or diseases that damage gland tissue reduce saliva output. Without saliva's buffering and washing action, acids linger on teeth and decay accelerates.
2. Sialadenitis: when saliva flow slows, bacteria from the mouth travel up the duct into the gland and multiply, causing painful swelling that worsens quickly.
3. Sialolithiasis: calcium salts slowly crystallise around debris in the duct, forming a stone. At mealtimes the gland tries to pump saliva past the blockage, producing the classic "meal-time" swelling and sharp pain that settles between meals.

Worked Example

A patient complains of dry mouth. The dentist measures unstimulated saliva: the patient spits into a cup for 5 minutes and collects 0.75 mL. Flow rate = 0.75 ÷ 5 = 0.15 mL per minute, which is below the normal 0.3–0.4 mL per minute, confirming hyposalivation. After switching her blood-pressure medicine and starting sugar-free gum to stimulate flow, a repeat test collects 1.9 mL in 5 minutes, giving 1.9 ÷ 5 = 0.38 mL per minute — back inside the normal range.

Common Misconceptions

• "Dry mouth just means I need more water." Drinking water wets the mouth briefly, but true xerostomia comes from low saliva production and needs saliva substitutes, stimulation or medicine changes.
• "A salivary stone always needs surgery." Small stones often pass with hydration, sour sweets or lemon drops that stimulate flow, and gland massage; only larger or stuck stones need procedures like sialendoscopy.
• "Swollen glands are always mumps." In adults, a painful one-sided swelling that spikes at mealtimes points more to a stone, while bilateral swelling with fever suggests infection.

Real-World Applications

• Dentists screen for dry mouth at every visit, because xerostomia patients need extra fluoride, more frequent cleanings and decay checks.
• Saliva flow measurement (sialometry) is a simple chairside test that turns a vague complaint into a number and tracks treatment progress.
• Ultrasound and sialography locate stones precisely, and sialendoscopy lets specialists remove them through the duct without cutting the gland out.

In short, xerostomia is low saliva that endangers the teeth, sialadenitis is an infected swollen gland needing prompt antibiotics, and sialolithiasis is a duct stone causing mealtime pain. Measuring flow, finding the blockage and treating the cause keeps these common gland problems from becoming serious.