Alveolar bone is the specialized bone that forms the sockets for teeth in the maxilla and mandible. It consists of alveolar bone proper surrounding the tooth root, supporting alveolar bone made of cortical plates and spongy bone, and bundle bone where periodontal ligament fibers insert. Osteoblasts build bone matrix while osteoclasts resorb it, allowing remodeling. With age, alveolar bone thins with wider marrow spaces and more fragile trabeculae, leading the alveolar crest to slope down distally as teeth tilt mesially.

1. ALVEOLAR BONE

2. DEFINITION
• Bone is specialized Connective Tissue with calcified
intercellular substance
• Alveolar bone is specialized part of maxillary and
mandibular bone that forms the primary support
structure for teeth

6. CLASSIFICATION OF BONE
• Shape :
• Long
• Short
• Flat
• Irregular bone
• Development:
• Endochondral
• Intramembranous
• Microscopic structure:
• Embryonic or woven bone
• lamellar bone
• Macroscopic structure:
• Compact bone
• Sponge (cancellous ) bone

7. COMPOSITION

8. FUNCTION OF BONE
• Give shape and support of the body
• Insertion for muscles and ligaments of the body
• Bone marrow is a site for blood cells production
• Alveolar bone holds the teeth firmly in position to masticate
• Supplies vessels to periodontal ligaments and cementum
• Houses and protects developing permanent teeth while
supporting primary teeth

9. GROSS HISTOLOGY OF THE BONE

13. CELLSOF THE BONE
• Osteoblasts: these are mononucleated cells which synthesise
and secrete the bone matrix
• Osteocytes: inactive osteoblasts which get entrapped within
the bone are called as osteocytes.
• Osteoclasts: cells responsible for resorption of bone. These
are large cells having 15-20 nuclei.
 Derived from monocytes – macrophages
 Contain acid phosphatase enzyme
 Has a ruffled border on the cell surface, more
mitochondria and less rough endoplasmic reticulum.
 Always found in concave areas know as “Howships
lacunae”

17. ALVEOLAR PROCESS

18. ALVEOLAR BONE (PROCESS)
• Definition: alveolar process is that
part of maxilla and mandible that
forms and supports the sockets of
teeth.
• Development: it starts in the second
month of fetal life
• Developing tooth buds are enclosed
in these grooves.
• Major portion of the alveolar process
begins with root formation and
eruption of the teeth.
• During rapid growth alveolar crest
shows characteristics of cartilage and
bone - CHONDROID BONE

19. STRUCTURE OF ALVEOLAR BONE
ALVEOLAR
BONE
ALVEOLAR
BONE
PROPER
LAMELLATED
BONE
BUNDLE
BONE
SUPPORTING
ALVEOLAR
BONE
CORTICAL
PLATE
SPONGY
BONE

20. ALVEOLAR BONE PROPER
• It surrounds the root of the tooth and gives attachment to the
periodontal ligament fibres.
• It consists of
• Lamellated bone
• Bundle bone
Lamellated bone consists of osteons.
Concentric lamellae along with a central blood vessel form an
osteon.

22. BUNDLE BONE
• Part of the alveolar bone where periodontal ligament fibres
are inserted (attached).
• Bundle – bundles of fibres
• Sharpeys fibres – principal fibres of the periodontal ligament
that are embedded in the bone or cementum.
• Sharpeys fibres are seen perpendicular to the bundle bone.
• Other fibrils are less and are arranged parallel to the bundle
bone surface

23. • Radiographically is more radiodense due to presence of thick
bone without trabeculations and is called as “lamina dura”
• Alveolar bone proper has many openings for blood vessels and
nerves – is perforated and is called as “cribriform plate”
• Interdental and interradicular septa have canals known as
canals of “ zukerkandl and hirschfeld”

24. LAMINA DURA

25. SUPPORTING ALVEOLAR BONE
• It consists of two parts –
 Cortical plates (Outer and inner)
 Spongy bone
Cortical plates: these are made up of
compact bone & form the outer and
inner plates of alveolar bone.
Cortical bone varies in thickness in
different areas – it is thicker in the
mandible than in the maxilla and
thicker in the premolar-molar
region than in the anteriors.

26. • Spongy bone: it fills the area between the cortical plates and
the alveolar bone proper.
• It contains trabaculae of bone and marrow spaces.
• Types of spongy bone (spongiosa) :-
 Type I: the trabaculae are regular and horizontal like a
ladder. This is seen most commonly in the mandible.
 Type II: irregularly arranged delicate and numerous
trabaculae. This is seen most commonly in the maxilla.
The spongy bone is very thin or absent in the anterior
regions of both the jaws.

27. Spongy bone
Spongy bone

28. ALVEOLAR CREST (CREST OF ALVEOLARSEPTA):
• Alveolar bone proper meets cortical plates at the alveolar
crest
• In healthy mouths the alveolar crest is around 1.5 to 2 mm
below the cementoenamel junction.

29. DEVELOPMENT OF BONE
• Endochondral bone formation

30. • Intramembranous bone formation

31. BONE REMODELING AND RESORPTION
• Bone is a dynamic tissue and is always undergoing changes
to adapt for functional forces, mesial drift, and eruption of
teeth.
• There is constant formation and resorption of bone. Periods
of resorption alternate with periods of rest and repair.
• Lines seen in bone:
• Resting line: these lines correspond to the resting period in
the process of continous bone formation.
• Reversal line: when a period of bone resorption is followed
by bone formation, a dark line is seen which seperates the
new bone from old bone, this resembles the shape of
howships lacunae.

32. BONE REMODELING

33. AGE CHANGESIN ALVEOLARBONE
• Brittleness due to decreased water content
• Sponge bone become thin trabecula , wide marrow spaces
• Red bone marrow become fatty
• Osteoporosis
• Alveolar crest slope distally due to mesial tilting of teeth
• With loss of teeth and resorption of alveolar ridge mental
foramen become very close to the ridge in mandible also
maxillary sinus in upper jaw