Alveolar bone and tooth eruption

Why this matters

This is the bone every extraction, every implant, every periodontal chart and every orthodontic appliance acts on — and it is the only bone in your body that exists because a tooth is there. Take the tooth away and the process starts dismantling itself within days, which is why a lower denture that fitted a decade ago no longer does, and why the shape of an upper anterior ridge two months after an extraction is decided by a fraction of a millimetre of bone nobody can see clinically. The same tissue is what a tooth erupts through, what a primary tooth is shed from, and what an orthodontist rebuilds around a root.

The big picture

One tissue, built for a tooth and dismantled without one. It is remodelled continuously by cells you already met in Y1-04.04, it is the bone half of the attachment whose cementum half is Y1-04.12, and it is what eruption, exfoliation and orthodontic movement all act on — the same cells, driven by a follicle, a programme, or an appliance.

The 15 cards in this lesson

1. 01The alveolar process is the only bone you own that exists because a tooth is there
2. 02Four layers, and only one of them lines the socket
3. 03Bundle bone, alveolar bone proper, cribriform plate and lamina dura are not four names for one thing
4. 04The white line overstates the bone and the dark line beside it understates the ligament
5. 05How thick is the buccal plate? Four datasets, four methods, and every one is at its own limit
6. 06Two-thirds of the total change happens in the first three months, and phase two is unexplained
7. 07Both ends of the load curve are pathological, and the middle is a plateau
8. 08Resorption is fast, formation is slow, and the cycle does not quite break even
9. 09Eruption has three phases, and the osteoclasts arrive before the tooth moves
10. 10The root does not push the tooth out of the bone
11. 11Eruption timing is a distribution with a named population, not a date
12. 12Clinical alert — in the lesson
13. 13Physiological root resorption stops and starts, and that is why a loose primary tooth can tighten again
14. 14Orthodontics rebuilds the socket around the tooth, and heavier force makes it slower
15. 15Clinical alert — in the lesson

You have got it when

You can now: (1) say why the alveolar process is tooth-dependent and has no boundary with basal bone; (2) separate bundle bone, alveolar bone proper, cribriform plate and lamina dura, and say what an absent one permits; (3) quote the buccal-plate and post-extraction figures with their denominators; (4) name the three eruption phases and the fate of the reduced enamel epithelium; (5) explain why heavier orthodontic…