Salivary Glands and Salivation,

Transcription

1 Salivary Glands and Salivation, WHAT DO I NEED TO KNOW AS A DENTAL STUDENT? Fionnuala Loy 4th Year, Dental Science Dublin Dental Hospital

2 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

3 Salivary Glands Where are they? Important to know: Relations of each gland Superiorly Inferiorly Medially Laterally Anteriorly Posteriorly Nerve supply Blood Supply Lymphatic Drainage

4 Submandibular and Sublingual Glands

5 Parotid Gland

6 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

7 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, 12 th Edition: Copyright The McGraw-Hill Companies, Inc.

8 Histological Picture

9 Where are the salivary ducts located intraorally? Parotid (Stensen) duct opening Parotid Papilla. Submandibular (Wharton) duct opening Sublingual Caruncle. Plica Sublingualis Parotid Papilla Sublingual Caruncle Sublingual duct opening Via Duct of Bartholin Sublingual Caruncle. OR Via smaller Ducts of Rivinus Plica Sublingualis.

10 Histology Cells lining the acini are serous, mucous or mixed. H&E staining.

11 Histology by Gland Type Serous Acini - Parotid Mucous Acini - Sublingual Mixed Acini Submandibular Demilunes mucous acini capped by serous crests

12 Saliva Formation Stage 1: Primary Saliva Local Vasculature Water and ions derived from plasma Isotonic Primary Saliva DUCT Reeves 2013 ACINI

13 Saliva Formation Stage 2: Final Saliva Na + & Cl - K + Isotonic Primary Saliva Concentration Gradient Hypotonic Final Saliva Reeves 2013 H 2 O

14 The Main Functions of Saliva in relation to its Constituents. Adapted from Nieuw Amerongen et al., 2004

15 The Main Functions of Saliva in relation to its Constituents. Adapted from Nieuw Amerongen et al., 2004

16 4. Salivary Biofilm Formation Tertiary Coloniser. Increased complexity: Gram negative, strict anaerobes. 3. Fusobacterium nucleatum joins in facilitating adhesion by other bacteria (gram negative, anaerobes ) Adhesion of primary colonisers: gram positive bacilli and cocci (S. sanguis, S. oralis ) and growth Formation of acquired pellicle with salivary proteins on the enamel.

17 Clinical Picture

18 Saliva Buffering Systems 1. Bicarbonate Buffering System 2. Protein Buffering System 3. Phosphate Buffering System

19 Saliva Buffering Systems 1. Bicarbonate Buffering System 2. Protein Buffering System 3. Phosphate Buffering System

20 Demineralisation ph < 5.5 Ca 10 (P0 4 ) 6 (OH) 2 Ca 2+ + P HP Hydroxyapatite in enamel Free ions in saliva H 2 P0 4 - H 3 P0 4

21 Remineralisation ph > 6.5 Ca 10 (P0 4 ) 6 (OH) 2 Ca 2+ + P HP Hydroxyapatite in enamel Free ions in saliva H 2 P0 4 - H 3 P0 4

22 Clinical Picture Early, Reversible, White Spot Lesion. Reversible caries = early enamel lesions Late, Irreversible, Established Lesion Irreversible caries = dentine caries

23 It s all a balancing act

24 Fluoride as a Protective Factor

25 Salivary Flow Rate

26 Salivary Flow Rate

27 Control of Saliva Secretion

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

29 Stimulated Saliva Flow Effect of six chewing gums 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)

30 Composition of Saliva Saliva and Oral Health Edgar M, Dawes C, O Mullane D Eds. 4th Ed 2012 Composition Unstimulated Stimulated Water 99.55% 99.53% Solids 0.45% 0.47% Flow Rate(ml/min) ph Sodium (mmol/l) Potassium Bicarbonate Phosphate Chloride ± Calcium 1.32 ± ± 0.35

31 Bicarbonate as a Buffer

32 Main differences between Stimulated and Unstimulated Saliva Resting Saliva Secretion -Submandibular - 60% -Parotid - 25% -Sublingual ~ 7-8% -Minor glands ~ 7-8% Oral Protection System - Secretion rate: mls/min - Texture: Viscous (mucus) - Rich in mucins - ph value Main Functions: Coating of the teeth: salivary pellicle - Lubrication of oral mucosa Stimulated Saliva Secretion -Parotid 60% -Submandibular 30% -Sublingual ~ 10% and minor glands Oral Repair System - Secretion rate: 1-3mls/min - Consistency: Thin (serous) - Rich in minerals - ph value: Main Functions: Clearance, buffer system, remineralisation

33 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)

34 Effect of Saliva Flow on Oral Clearance Unstimulated salivary flow rate <0.2mL/min = prolonged clearance. Prolonged clearance = > risk of caries and acid erosion. 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)

35 Effect of Saliva Flow on Buffering Capacity Plaque ph response to a sucrose mouthrinse alone, and followed by paraffin or cheese. (Edgar and Higham, Redrawn from: Higham and Edgar, Caries Res 1989; 23: 42-48)

36 Effect of Saliva Flow on Buffering Capacity

37 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 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 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

38 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.

39 Aetiology of Xerostomia

40 Classification of Salivary Gland Disease Salivary Gland Diseases Developmental Atresia Aplasia Heterotopic Salivary tissue Sialadenitis Obstruction & traumatic lesions Bacterial Salivary Calculi Chronic Necrotizing Acute Sialometaplasia Viral Mumps CMV Post-irradiation Sarcoidosis Sialadenitis of minor glands Sjogren Syndrome Sialadenosis HIV-associated salivary gland disease Salivary Gland Tumour Age related changes Adenoma: Pleomorphic adenoma Warthin s tumour Carcinoma: Mucoepidermoid Acinic Cell Adenoid Cystic Carcinoma arising in PA Pleomorphus, lowgrade adenocarcinoma

41 Diagnosis - History ALWAYS: History Medical Social Pain - SOCRATES IMPORTANT QUESTIONS RELATED TO SALIVARY GLANDS: History of Swelling/changes over time? Trismus? 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

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

43 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)

44 Diagnosis-Intraoral

45 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.

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

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

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

49 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

50 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.

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

52 Thank You for Listening Any Questions?