[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Dentistry](https://durgical.com/en/dentistry/) › [Dental anatomy and histology](https://durgical.com/en/dentistry/areas/anatomy-histology/) › Saliva and the oral microbiome # Saliva and the oral microbiome - Anatomy and histology Saliva washes the teeth, neutralises acid and fights germs. When it is lacking, caries, thrush and mouth sores follow. Updated Nov 12, 2026 **See it in 3D:** [Parotid gland](https://durgical.com/en/anatomy/parotid-gland/) · [Submandibular gland](https://durgical.com/en/anatomy/submandibular-gland/) · [Sublingual gland](https://durgical.com/en/anatomy/sublingual-gland/) · [Tongue](https://durgical.com/en/anatomy/tongue/) ## Key points - Saliva buffers acid, remineralises enamel and is antimicrobial. - Dry mouth leads to cervical caries and candidiasis. - Anticholinergic drugs are the commonest cause of dry mouth in older adults. ## What it is Three pairs of major salivary glands (parotid, submandibular and sublingual) and hundreds of minor glands produce saliva, mostly under parasympathetic control. Saliva lubricates food, starts starch digestion with amylase, buffers acid with bicarbonate, supplies calcium and phosphate that remineralise enamel, and carries antimicrobial proteins such as lysozyme, lactoferrin and secretory IgA. The mouth hosts one of the richest microbial communities in the body; on the teeth it forms an organised biofilm (dental plaque). Disease comes when the balance shifts, for example with frequent sugar, which favours acid-producing bacteria such as mutans streptococci. ## Clinical anatomy - Parotid: serous saliva, duct opening opposite the upper second molar; innervated through the glossopharyngeal nerve (IX). - Submandibular and sublingual: mixed saliva; ducts open under the tongue; innervated through the facial nerve (VII, chorda tympani). - Submandibular gland makes most of the resting saliva; the parotid adds most of the stimulated flow. - Plaque: a biofilm of bacteria in a matrix, which hardens into calculus (tartar) when mineralised. ## Clinical correlation - Reduced saliva (drugs, radiotherapy, Sjögren disease, dehydration) causes rapid caries at the necks of the teeth, candidiasis and difficulty with dentures. - Anticholinergic drugs are the most common cause of dry mouth in older adults. - The submandibular duct is long and runs uphill, so stones form there most often. - Oral bacteria entering the blood after procedures or with poor oral health can cause infective endocarditis (viridans streptococci) or aspiration pneumonia. ## Next step / Initial management - Dry mouth: review medicines, hydration and diabetes; ask about dry eyes and joint pain for Sjögren disease. - Advise frequent sips of water, sugar-free gum, fluoride toothpaste and dental review every few months while the mouth stays dry. - Painful salivary swelling at meals suggests a stone: refer to ENT or maxillofacial surgery; persistent or hard swelling needs referral to exclude a tumour. ## Test yourself Think of the answer, then tap the question to see it. ## What are three ways saliva protects the teeth? It buffers acid with bicarbonate, supplies calcium and phosphate to remineralise enamel, and contains antimicrobial proteins such as lysozyme and IgA. ## Which gland most often forms stones, and why? The submandibular gland, because its duct is long and runs upward, and its saliva is more viscous. ## Which oral bacteria are a classic cause of infective endocarditis? Viridans group streptococci from the mouth. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/dentistry/saliva-and-the-oral-microbiome/) ## Elsewhere in DurgiPedia - [Salivary secretion](https://durgical.com/en/physiology/salivary-secretion/) - [Salivary glands: serous and mucous acini](https://durgical.com/en/histology/salivary-glands-serous-and-mucous-acini/) - [Salivary glands: parotid, submandibular and sublingual](https://durgical.com/en/ent/salivary-glands-parotid-submandibular-and-sublingual/) ## Connections ## See it in 3D 4 The structures of Durgical's 3D anatomy where it is found. - [Parotid gland](https://durgical.com/en/anatomy/parotid-gland/) - [Submandibular gland](https://durgical.com/en/anatomy/submandibular-gland/) - [Sublingual gland](https://durgical.com/en/anatomy/sublingual-gland/) - [Tongue](https://durgical.com/en/anatomy/tongue/) ## Related 3 - [Dry mouth (xerostomia): approach](https://durgical.com/en/dentistry/dry-mouth-approach/) - [How caries forms: biofilm, sugar and demineralisation](https://durgical.com/en/dentistry/how-caries-forms-biofilm-sugar-and-demineralisation/) - [Oral candidiasis (thrush)](https://durgical.com/en/dentistry/oral-candidiasis/) ## Related conditions 2 - [Sialolithiasis (salivary stones)](https://durgical.com/en/conditions/sialolithiasis/) - [Sjögren disease](https://durgical.com/en/conditions/sjogren-disease/) [← All of dentistry](https://durgical.com/en/dentistry/) Educational content; it does not replace assessment by a dentist or doctor and is not a clinical instruction. For facial or neck swelling with difficulty swallowing or breathing, a knocked-out tooth or bleeding that will not stop, go to an emergency department at once. Sources: [Anatomy, Head and Neck, Salivary Glands](https://www.ncbi.nlm.nih.gov/books/NBK538325/) (StatPearls Publishing (NCBI Bookshelf), 2023); [Xerostomia](https://www.ncbi.nlm.nih.gov/books/NBK545287/) (StatPearls Publishing (NCBI Bookshelf), 2023); [Dental Caries](https://www.ncbi.nlm.nih.gov/books/NBK551699/) (StatPearls Publishing (NCBI Bookshelf), 2023). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/dentistry/saliva-and-the-oral-microbiome/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/dentistry/saliva-and-the-oral-microbiome/