OCB02-2022 Flashcards
Describe the whole mouth unstimulated salivary flow rate.
0.35ml/min but shows circadian rhythm
Lowest from 6-9am and highest from 3-6pm
What is the whole mouth salivary flow rate during sleeping?
0.1ml/min
What is the whole mouth stimulated salivary flow rate?
2ml/min
How much saliva is produced in 24 hours?
~600ml
On average, how much of the day is spent experiencing unstimulated, stimulated and sleeping salivary flow rates?
Unstimulated = 15hrs
Stimulated = 2hrs
Sleeping = 7hrs
What might be the reason for a lower salivary flow rate during sleeping?
Decreased CNS higher centre activity so loss of positive effect on salivary nuclei
What are each of the salivary glands contributions to whole mouth salivary flow rates at rest/unstimulated?
Parotid = 28% or 0.1ml/min
Submandibular/sublingual = 68% or 0.24ml/min
Minor = 4% or <0.05ml/min
What are each of the salivary glands contributions to whole mouth salivary flow rates during stimulation?
Parotid = 53% or 1.05ml/min
Submandibular/sublingual = 46% or 0.92ml/min
Minor = 1% or <0.1ml/min
Which salivary glands contribute the most to each of unstimulated and stimulated salivary flow rates?
Unstimulated = submandibular/sublingual (68%)
Stimulated = parotid (53%)
What is the consistency of saliva at rest and why?
Thick, sticky
Larger contributions from submandibular and sublingual glands = more mucin (also from minor glands)
Protective/covers surfaces
What is the consistency of saliva at rest and why?
Watery
Larger contributions from parotid glands
Moistens food and initiates digestion
What unstimulated salivary flow rates are considered normal and low?
Normal = >0.25ml/min
Low = 0.1-0.2ml/min
Very low = <0.1ml/min
What stimulated salivary flow rates are considered normal and low?
Normal = >1.0ml/min
Low = 0.7-1.0ml/min
Very low = <0.7ml/min
What can decrease salivary flow rate?
Age
Certain prescribed medications
Does the size of salivary glands affect salivary flow rate?
Yes - larger glands have higher flow rates (so males > females)
Is the salivary film thinner on soft or hard surfaces?
Thinner on hard surfaces
On which part of the oral mucosa is the salivary film thickest?
Anterior tongue (50μm)
On which part of the oral mucosa is the salivary film thinnest?
Hard palate (10μm)
What do people with dry mouth experience?
Dry mouth during the day
Night waking due to dryness
Burning sore mouth and tongue
Candidiasis
Bad taste
Dental caries
Denture discomfort
Difficulty speaking, swallowing, eating
How many bacteria are in saliva?
~10^8/ml
Name some things found in saliva.
Epithelial cells, neutrophils
Micro-organisms
Exosomes
Mucins (MUC5B, MUC7)
Electrolytes/ions
Antibodies (IgA and IgG)
Hormones, cytokines, enzymes
What are the 4 main functions of saliva?
Tooth protection
Protection and maintenance of oral mucosa
Regulation of oral microbiota
Taste and processing of food and nutrients
Describe the tooth protection role of saliva.
Increased flow rate = increased clearance of sugar and bacteria to decrease risk of caries
pH buffering with bicarbonate and carbonic anhydrase 6 (stimulated = 30mmol) to neutralise acids and prevent hydroxyapatite dissolution
Acquired enamel pellicle (<1μm) prevents surface mineralisation but increases sub-surface remineralisation; decreases friction by 20x to decrease abrasion
Saliva supersaturation with calcium phosphate (resting = 2mmol) and calcium binding proteins (eg statherins) to stimulate remineralisation
Describe the protection and maintenance of oral mucosa role of saliva.
Salivary film contains a network of protein with pores = formed of mucin (MUC5B)
This allows <100nm soluble globular proteins (eg albumin) through easily but restricts movement of larger objects like bacteria to act as a barrier
Increases lubrication of oral tissues
Moistening and hydration aid in wound healing
Describe the regulation of oral microbiota role of saliva.
Maintain normal numbers and composition of oral microbiota
Saliva flow clears some microbes
Acquired enamel pellicle modifies adherence of microbes to teeth by acting as binding sites for commensals
Agglutinins, mucins and other proteins aggregate microbes to facilitate their clearance from the mouth
Salivary proteins can modulate microbial growth - eg sugars on mucins
Many antimicrobial growth-limiting factors in saliva = histatins, IgA, defensins
Name some primary colonisers and what molecules they adhere to in the acquired pellicle.
S.oralis, S.gordonii, S.sanguis
Sialylated mucins
Proline-rich proteins
Salivary agglutinin
Bacterial cell fragments
α-amylase
Name some antibacterial compounds found in saliva.
Cystatins, histatins
Defensins
Cathelicidins
Lysozyme
Lactoperoxidase
Lactoferrin
Chromogranin A
Immunoglobulins
PLUNCs
Name some antifungal compounds found in saliva.
Histatins
Defensins
Cathelicidins
Chromogranin A
Immunoglobulins
Mucin-derived proteins
Name some antiviral compounds found in saliva.
Cystatins
Mucins
Immunoglobulins
SLPI
