The periodontium: gingiva, ligament, cementum and alveolar bone
- Anatomy and histology
The periodontium is everything that holds a tooth in place: the gum, the ligament, the root surface and the bone. Gum disease destroys it.
See it in 3D: Gums (gingiva) · Mandible · Maxillae
What it is
The periodontium is the supporting apparatus of the tooth. It has four parts: the gingiva, which seals the bone and roots from the mouth; the periodontal ligament, a thin layer of collagen fibres that suspends the tooth in its socket and senses pressure; the cementum on the root surface, into which the ligament fibres insert; and the alveolar bone that forms the socket. Healthy gingiva is pink, firm and stippled, and a shallow groove (the gingival sulcus) surrounds each tooth.
Clinical anatomy
- Gingiva: free gingiva around the neck, attached gingiva bound to bone, and the papillae between teeth.
- Gingival sulcus: normally up to about three millimetres deep; deeper measurements on probing are periodontal pockets.
- Junctional epithelium: attaches the gum to the tooth at the bottom of the sulcus; it is the first barrier bacteria break.
- Periodontal ligament: collagen (Sharpey) fibres between cementum and bone; it absorbs chewing forces and gives the sense of bite.
- Alveolar bone: exists because the teeth exist; it resorbs after a tooth is lost.
Clinical correlation
- Gingivitis inflames only the gingiva and is reversible; periodontitis destroys ligament and bone and is not.
- Bone loss around teeth is seen on radiographs and is what makes teeth loose and drift.
- After extractions the alveolar ridge shrinks, which affects dentures and implants.
Next step / Initial management
- Bleeding gums: look for plaque, swelling and pocketing; reinforce brushing and flossing and refer to the dentist for cleaning.
- Loose teeth in an adult without trauma: refer to the dentist for periodontal assessment and radiographs.
- Rapid periodontal destruction in a young person: refer and screen for diabetes and immune disorders.
Test yourself
Think of the answer, then tap the question to see it.
What are the four tissues of the periodontium?
Gingiva, periodontal ligament, cementum and alveolar bone.
What is the difference between gingivitis and periodontitis?
Gingivitis is reversible inflammation of the gum only; periodontitis destroys ligament and bone and causes irreversible attachment loss.
What happens to the alveolar bone after a tooth is extracted?
It resorbs and the ridge shrinks, because the bone exists to support the tooth.
Connections
See it in 3D3
The structures of Durgical's 3D anatomy where it is found.
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: Histology, Periodontium (StatPearls Publishing (NCBI Bookshelf), 2023); Anatomy, Head and Neck, Oral Gingiva (StatPearls Publishing (NCBI Bookshelf), 2023); Periodontitis (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.