Salivary Glands and

Salivation , WHAT DO I NEED TO KNOW AS A DENTAL STUDENT?

Fionnuala Loy 4th Year, Dental Science Dublin Dental Hospital Contents

1. Anatomy, Histology and Physiology of Salivary Glands

2. Saliva Functions

3. Saliva Flow Rate

4. Xerostomia – Clinical Relevance

5. Saliva as a Diagnostic Aid

Salivary Glands – Where are they?

Important to know:  Relations of each gland • Superiorly • Inferiorly • Medially • Laterally • Anteriorly • Posteriorly  Nerve supply  Blood Supply  Lymphatic Drainage Submandibular and Sublingual Glands Parotid Gland Clinical Relevance of Parotid Anatomy .Transient Facial Nerve Paralysis .Cause - . Introduction of LA into the capsule of the parotid gland. .Prevention – . Adhering to protocol with IDN block . Needle tip should be in contact with bone .Management – . Reassure patient . Remove Contact lenses . An eye patch should be applied to affected eye . Review patient

Salivary Gland Structure .Compound tubuloalveolar glands. .Structure: . Closely packed acini with ducts packed in between. . Supported by CT which divides the gland into lobules. Ducts: .Smallest , intercalated ducts – lined by simple, cuboidal epithelium. .Intercalated ducts open into striated ducts – lined by simple cuboidal/columnar epithelium. .Striated ducts open into excretory ducts - lined by simple columnar epithelium Mescher AL: Jaqueira’s Basic Histology: Text and Atlas, 12th Edition: http://www.accessmedicine.com Copyright © The McGraw-Hill Companies, Inc.

Histological Picture Where are the salivary ducts located intraorally?

Parotid (Stensen) duct opening Parotid Papilla.

Submandibular (Wharton) duct opening Sublingual Caruncle.

Plica Sublingualis Sublingual Caruncle Sublingual duct opening – Via Duct of Bartholin Sublingual Caruncle. OR Parotid Papilla Via smaller Ducts of Rivinus Plica Sublingualis. Histology • Cells lining the acini are serous, mucous or mixed. • H&E staining. Histology by Gland Type

Serous Acini - Parotid Mucous Acini - Sublingual Mixed Acini – Submandibular ‘Demilunes’ – mucous acini capped by serous crests Saliva Formation – Stage 1: Primary Saliva

Local Vasculature

Water and ions derived from plasma

Isotonic ©Reeves 2013

Primary Saliva DUCT

ACINI Saliva Formation – Stage 2: Final Saliva

Na+& Cl- K+

Isotonic Hypotonic Concentration Gradient Primary Saliva Final Saliva

©Reeves 2013

H2O The Main Functions of Saliva in relation to its Constituents. Adapted from Nieuw Amerongen et al., 2004 The Main Functions of Saliva in relation to its Constituents. Adapted from Nieuw Amerongen et al., 2004 Salivary Biofilm Formation Tertiary Coloniser. Increased 4. complexity: Gram negative, strict anaerobes.

Fusobacterium nucleatum 3. joins in – facilitating adhesion by other bacteria (gram negative, anaerobes…)

Adhesion of primary 2. colonisers: gram positive bacilli and cocci (S. sanguis, S. oralis…) and growth

Formation of acquired pellicle 1. with salivary proteins on the enamel. Clinical Picture Saliva Buffering Systems 1. Bicarbonate Buffering System

2. Protein Buffering System

3. Phosphate Buffering System Saliva Buffering Systems 1. Bicarbonate Buffering System

2. Protein Buffering System

3. Phosphate Buffering System Demineralisation pH < 5.5

2+ 3- 2- Ca10(P04)6(OH)2 Ca + P04 HP04 H P0 - Hydroxyapatite in Free ions in saliva 2 4 enamel H3P04 Remineralisation pH > 6.5

2+ 3- 2- Ca10(P04)6(OH)2 Ca + P04 HP04 H P0 - Hydroxyapatite in Free ions in saliva 2 4 enamel H3P04 Clinical Picture Early, Reversible, White Spot Lesion. Reversible caries = early enamel lesions

Late, Irreversible, Established Lesion Irreversible caries = dentine caries It’s all a balancing act Fluoride as a Protective Factor Salivary Flow Rate Salivary Flow Rate Control of Saliva Secretion Unstimulated Saliva Flow

The Circadian rhythm in unstimulated salivary flow rate and the idealised effect of sleep. (Dawes, 2004) Stimulated Saliva Flow

Effect of six chewing and gum base on flow rate of whole saliva. Unstimulated saliva was collected for 5 minutes prior to stimulation through chewing gum or gum base, which began at time zero. (Dawes, 2004) Composition of Saliva Composition Unstimulated Stimulated Saliva and Oral Health Edgar M, Dawes C, O’Mullane D Eds. 4th Ed 2012 Water 99.55% 99.53%

Solids 0.45% 0.47%

Flow Rate(ml/min) 0.32  0.23 2.08  0.84

pH 7.04  0.28 7.61  0.17

Sodium (mmol/L) 5.76  3.43 20.67  11.74

Potassium 19.47  2.18 13.62  2.70

Bicarbonate 5.47  2.46 16.03  5.06

Phosphate 5.69  1.91 2.70  0.55

Chloride 16.40 ± 2.08 18.09  7.38

Calcium 1.32 ± 0.24 1.47 ± 0.35

Bicarbonate as a Buffer Main differences between Stimulated and Unstimulated Saliva

Resting Saliva Oral Protection System Secretion - Secretion rate: 0.3-0.4 mls/min -Submandibular - 60% - Texture: Viscous (mucus) -Parotid - 25% - Rich in mucins -Sublingual ~ 7-8% - pH value 5.7-7.1 -Minor glands ~ 7-8% -Main Functions: Coating of the teeth: salivary pellicle - Lubrication of Stimulated Saliva Oral Repair System Secretion - Secretion rate: 1-3mls/min -Parotid 60% - Consistency: Thin (serous) -Submandibular 30% - Rich in minerals -Sublingual ~ 10% - pH value: 7.0-7.8 and minor glands - Main Functions: Clearance, buffer system, remineralisation Effect of Saliva Flow on Oral Clearance

. Higher Salivary Flow rate = faster Oral Clearance of Sucrose.

The effect of changes in the unstimulated flow rate on the clearance of sucrose after a 10% sucrose mouthrinse. Clearance is greatly prolonged at low flow rates. (Dawes, 2004) Effect of Saliva Flow on Oral Clearance

. Unstimulated salivary flow rate <0.2mL/min = prolonged clearance.

. Prolonged clearance = > risk of caries and .

The effect of changes in the unstimulated flow rate on the clearance of sucrose after a 10% sucrose mouthrinse. Clearance is greatly prolonged at low flow rates. (Dawes, 2004) Effect of Saliva Flow on Buffering Capacity

Plaque pH response to a sucrose mouthrinse alone, and followed by paraffin or cheese. (Edgar and Higham, 2004. Redrawn from: Higham and Edgar, Caries Res 1989; 23: 42-48) Effect of Saliva Flow on Buffering Capacity Xerostomia .Literally translated ‘xerostomia’ means “dry, oral cavity”. .Symptomatic description. .Patients first complain of dry mouth when salivary flow rates are less than half that of normal. .More than 50% of adults surveyed in 2000– 2002 reported having some experience of dry mouth. . Dry mouth on a regular basis was reported by 12% of older people (aged 65+) compared to only 5–6% among younger adults (aged 16–24 and 35–44).*

* Whelton H, Crowley E, O’Mullane D, Woods N, McGrath C, Kelleher V, Guiney H, Byrtek M. Oral Health of Irish Adults 2000–2002.

Hyposalivation .True Hyposalivation is defined as: .Unstimulated saliva flow rate of less than 0.1 ml per minute. .Stimulated saliva flow rate of less than 0.7 ml per minute. .Not everyone with xerostomia will have true hyposalivation.

Measuring salivary flow is important in diagnosing true hyposalivation. Aetiology of Xerostomia Classification of

Salivary Gland Diseases

Obstruction & Sjogren HIV-associated Salivary Gland Age related Sialadenosis Developmental traumatic lesions Syndrome changes disease •Adenoma: •Bacterial •Salivary Calculi •Atresia • •Chronic •Necrotizing •Aplasia •Warthin’s tumour •Acute Sialometaplasia •Heterotopic •Carcinoma: •Viral Salivary •Mucoepidermoid • tissue •Acinic Cell •CMV •Adenoid Cystic •Post-irradiation •Carcinoma arising in •Sarcoidosis PA •Sialadenitis of •Pleomorphus, low- minor glands grade

Diagnosis - History ALWAYS: •History • IMPORTANT QUESTIONS RELATED TO SALIVARY GLANDS: •Medical • History of Swelling/changes over time? •Social • ? • Pain - SOCRATES • Pain? • Variation with meals? • Bilateral? • Dry mouth/Dry eyes? • Does the amount of saliva in your mouth seem to be too little? • Does your mouth feel dry when eating a meal? • Do you sip liquids to aid in swallowing dry food? • Do you have difficulty swallowing? • Recent exposure to sick contacts (mumps)? • Radiation therapy • Current medications

Diagnosis - Inspection

• Asymmetry (glands, face, neck) • Diffuse or focal enlargement? • Erythema extra-orally? • Trismus? • Medial displacement of structures intraorally? • Examine external auditory canal (EAC) Diagnosis - Palpation

• Palpate for cervical lymphadenopathy • Bimanual palpation of FOM in a posterior to anterior position. • Have a patient close mouth slightly and relax musculature to aid in detection • Examine for duct purulence • Bimanual palpation of the gland (firm or spongy/elastic)

Diagnosis-Intraoral Diagnosis – Special Tests .Measuring Salivary Flow Rate: .Standardised conditions. .Best measured in morning: 9am-11am. .Px should not eat, smoke, drink or clean his/her mouth 1 hour beforehand. .Px should sit with head forward slightly and swallow saliva before measurement. .Px allows saliva to drip into container for 5 minutes (without mechanical movements) into suitable collecting vessel. .At end point px spits remaining saliva from oral cavity into vessel. .Calculate flow rate per minute. Diagnosis: Special Tests

A) If Salivary Calculi suspected - B) If tumour suspected - D) If Sjogren's Syndrome or other • Lower occlusal radiograph • Refer to Oral Surgery systemic condition is suspected - Other imaging techniques - department for assessment • Refer to oral medicine for • CT Scan and possible biopsy assessment. • US • Sialography • Scintigraphy Other Special Tests: Refer to oral surgery if stone cannot be C) If medications are the •Biopsy removed non-surgically. suspected cause - •Blood Tests NB: • Liase with GP and see if •FBC Not all salivary calculi are radio-opaque an alternative can be •Anitbody screening: prescribed (Ant-La, Anti-Ro, ANA, RF)

•Candida smear or culture Symptomatic Treatment for Patient

• Sip water frequently • Maintain good OH • Use ice sticks • Bruch twice daily with • Restrict caffeine intake fluoride toothpaste • Avoid mouth rinses • Avoid tobacco, spicy, salty containing alcohol and acidic foods that can • Humidfy sleeping area irritate the mouth. • Coat with a lubricant • Sugar free gum.

Stimulation of Salivary Flow Local: Pharmacological "sialogogues.": .Masticatory-gustatory .Pilocarpine - 5 milligrams four times per day. stimulation e.g: sugar- .Cevimeline - 30 mg three times per day. free gum. .NB: Common Side Effects: .Sweating, nausea and rhinitis. .Contraindicated in px with: .Hypersensitivity .Narrow-angle glaucoma .Uncontrolled asthma .Caution with β-blocker use

Saliva Replacements .Best method – frequent lubrication with water. .Saliva Substitutes: . Negatives . Calcium, Phosphate and other ions compared to saliva – remineralisation. . Bad taste. . Complicated administration. . Cost. . More viscous than natural saliva – Carboxymethylcellulose

. Examples: Oral Balance, Xerostom

Management of Hyposalivation

.Education.

.Fighting infection eg: CHX mouthrinse, nystatin suspension

.Dietary History and advice.

.Professional Tooth Cleaning as needed.

.Fluoridation (toothpaste, gels, varnish and mouthwash)

.Restorative Treatment.

.Periodontal treatment.

Future of Saliva – A diagnostic Aid? .Measuring buffering capacity .Microbial testing .Diagnosing systemic disease?

Thank You for Listening

Any Questions?