Salivary Gland Function Quiz

Salivary Gland Diseases

• Salivary gland diseases are often identified by oral dryness (xerostomia) or a swelling/mass.

• Major salivary glands (parotid, submandibular, and sublingual) and numerous minor salivary glands throughout the mouth produce saliva.

• Parotid gland: mostly serous cells

• Submandibular gland: mixed serous and mucous cells

• Sublingual gland: mostly mucous cells

• Parotid saliva is secreted through Stensen's ducts.

• Submandibular saliva is secreted through Wharton's duct.

• Sublingual saliva may enter the mouth directly via the ducts of Rivinus.

Salivary Gland Anatomy and Physiology

• The secretory component of the glands are acinar cells ("grapes")

• The ductal component of the glands make up a branching system ("stems").

• Three types of ductal cells: intercalated, striated, and interlobular.

• Normal whole saliva (WS) comprises >99% water and <1% proteins/salts.

• Normal daily WS production is 0.5–1.5 liters.

• Factors that increase salivary flow: taste, smell, mechanical stimulation, pain, and hormonal changes during pregnancy and medications like sympathomimetics and parasympathomimetics

• Factors that decrease salivary flow: menopause-related changes, stress, anticholinergic agents, and antiadrenergic agents.

Diagnosis of Salivary Gland Disease

• Xerostomia: subjective complaint of dry mouth
• Hyposalivation: reduced salivary flow rate
• Hypersalivation (ptyalism): increase in saliva production.

Salivary Gland Dysfunction: Symptoms

• Dryness of oral mucosa (lips, throat), difficulty chewing/swallowing/speaking
• Oral pain, oral burning sensation, sore throat.
• Sensitivity to spicy or coarse foods, affecting nutrition.
• Frequent sipping of water to relieve oral dryness.

Clinical Examination

• Dry, cracked, and atrophied lips
• Pale, corrugated buccal mucosa.
• Smooth dorsal tongue (due to lost papillae) or fissured.
• Increased dental caries and erosive lesions due to the absence of saliva's protective properties
• Increased index of plaque and bleeding on probing (in xerostomia)
• Presence of lipstick or shed epithelial cells on maxillary teeth, indicating reduced saliva.
• Positive "tongue blade" sign (tissue adheres to the blade) in xerostomia.
• Candidiasis (oral fungal infection) is often associated with salivary gland dysfunction.
• Angular cheilitis (cracking in the corners of the mouth) is also common.
• Salivary gland enlargement, indicative of infection, inflammation, or tumor.
• Normally saliva expressed from major gland orifices should be colorless, transparent, watery, and copious. Cloudy or scant secretions indicate bacterial infection.

Sialometry

• Objective measurement technique for gland function—assessing unstimulated and stimulated salivary flow.
• Spitting (patient spits saliva into pre-weighed tube) and absorbent (pre-weighed sponge) methods.
• Normal unstimulated whole salivary flow is 40%–50% less than normal.
• Stimulation is possible using gum chewing, paraffin wax, or citric acid.
• Very low rates of both unstimulated and stimulated saliva indicate marked salivary gland hypofunction.

Salivary Gland Imaging

• Plain film radiography: detects radiopaque sialoliths and bony destruction in malignant neoplasms.
• Sialography: detects intrinsic/acquired ductal abnormalities like strictures, obstructions, dilatations, ruptures, and sialoliths; good for pre-surgical planning.
• Ultrasonography: assesses superficial masses in parotid/submandibular glands, inexpensive/widely available, good for delineating superficial lesions.
• Radionuclide salivary imaging (scintigraphy): dynamic, minimally invasive technique for assessing salivary gland function; assesses gland uptake/excretion and detects abnormalities, useful in cases where sialography is contraindicated (acute infection/iodine allergy).
• CT and CBCT: assesses acute inflammatory processes, mandibular cortical bone erosion/ destruction, and sialoliths.
• MRI: superior soft tissue resolution over CT, particularly for oral malignancies; less prone to artifacts; combined with sialography

Salivary Gland Biopsy

• Definitive diagnosis of salivary pathology requires histologic examination.
• Labial minor salivary glands are commonly biopsy-sampled due to easy accessibility
• Minor gland biopsy can diagnose amyloidosis, sarcoidosis, cGVHD
• Complications of this biopsy can include lower lip numbness (0-6%) and mucocele formation.
• Alternatively, major gland biopsies (usually parotid and submandibular) is done extraorally, or intraorally.
• FNAB (Fine-needle aspiration biopsy): Simple and effective for solid lesions, but not good for nonneoplastic tissues.

Sialendoscopy

• Diagnostic and therapeutic technique for salivary gland disorders.
• Following the endoscopic procedure, a stent is placed to allow for healing of the duct and maintain salivary flow.
• Sialendoscopy may also be combined with sialography to diagnose/treat obstructions.

Specific Diseases and Disorders of the Salivary Glands

1. Developmental Abnormalities

• Complete absence (aplasia/agenesis) of salivary glands.
• Hypoplasia of the parotid gland.
• Aberrant salivary glands (ectopic).
• Stafne bone defect (SBD).
• Accessory salivary ducts.
• Salivary gland diverticula

2. Sialolithiasis (Salivary Stones)

• Etiology groups:
  1. Factors favoring saliva retention (ductal irregularities, inflammation, dehydration, meds like anticholinergics/diuretics)
  2. Saliva composition (calcium saturation, crystallization inhibitors)
  3. Bacterial infection
• Submandibular glands are most commonly affected due to duct tortuosity and higher calcium and phosphate levels of the secretion.

3. Extravasation and Retention (Mucoceles and Ranulas)

• Mucoceles: Swelling caused by accumulation of saliva at a traumatized/obstructed minor salivary duct
• Ranulas: A form of mucocele located in the floor of the mouth, potentially due to extravasation of sublingual saliva.

4. Inflammatory and Reactive Lesions(Necrotizing Sialometaplasia)

• Benign, self-limiting inflammatory disorder often mistaken for a malignancy.
• Unknown etiology, but thought to be due to ischemia, infection, or immune response.

5. Acute and Chronic Allergic Sialadenitis

• Uncommon sialadenitis due to allergic effects of allergens on salivary glands.
• Characterized by acute salivary gland enlargement and itching.

6. Viral Diseases (Mumps, CMV)

• Viral infections causing salivary gland enlargement
• Mumps: Acute viral infection, often occurring in children.
• CMV: Common in immunocompromised individuals, potentially latent.

7. HIV-Associated Salivary Gland Disease

• Salivary gland swelling is a common presentation.
• May be attributed to acute sialadenitis or HIV-associated salivary gland disease (HIV-SGD).
• It's often associated with lymphadenopathy.

8. Hepatitis C Virus Infection

• HCV is hepatotropic, lymphotropic, and sialotropic.
• Xerostomia is common in chronic HCV patients.

9. Sialorrhea (Hypersalivation/Ptyalism)

• Excessive saliva production (or impaired clearance).
• Many causes, including medications, hyperhydration, neurological conditions, and local irritations.

Management of Xerostomia

• General:

  1. Good oral hygiene (frequent dental visits for patients with xerostomia).
  2. Diet (Avoid cariogenic foods. limit acidic foods/beverages).
  3. Saliva substitutes (aerosols/liquids).
  4. Medications (antidepressants, antihistamines)

• Specific:

  1. Topical fluoride.
  2. Sugar-free products, chewing gum.
  3. Water intake (sip throughout the day).

Treatment

• Treatment varies, depending on the condition.
  • Supportive, symptomatic treatment for mild cases.
  • Surgical intervention for severe cases: sialendoscopy dilation, removing the gland (in extreme cases).
  • Systemic medications (antibiotics/steroids).

Test your knowledge on salivary glands and their functions with this quiz. Questions cover normal saliva production, factors influencing salivary flow, conditions affecting salivation, and histological features of salivary glands. Perfect for students and professionals in dental and health sciences.