s

1. Author: Pi Date: 2025.XX.XX
Differential
Osteology of the
Maxilla and
Mandible

2. 6. Skeletal Adaptation
8. Conclusion
CONTENTS
1. Introduction
5. Classification of Bone Tissue
4. Specific Assessment Methodology
2. Biomechanical Studies
7. Bone Metabolism
3. Bone Physiology

3. Introduction
01

4. Overview
Although equal and opposite functional loads are delivered to the
maxilla and mandible, the maxilla transfers stress to the entire
cranium, whereas the mandible must absorb the entire load.
Consequently, the mandible is much stronger and stiffer than the
maxilla.

5. 3
2
1
The maxilla has relatively thin cortices that are interconnected by
a network of trabeculae (see Figs. 4-2, 4-4, and 4-5). Because it is
loaded primarily in compression, the maxilla is structurally
similar to the body of a vertebra.
The mandible, however, has thick cortices and more radially
oriented trabeculae (see Figs. 4-4 and 4-5). The structural array is
similar to the shaft of a long bone and indicates that the
mandible is loaded predominantly in bending and torsion.
A midsagittal section through the incisors (Fig. 4-4) and a frontal
section through the molar region (Fig. 4-5) show the distinct
differences in the osseous morphology of the maxilla and
mandible.
Structural Differences

6. 02
Biomechanical Studies

7. This biomechanical impression based on osteology is
confirmed by in vivo strain-gauge studies in monkeys.
Hylander demonstrated substantial bending and
torsion in the body of the mandible associated with
normal masticatory function (Fig. 4-6).
Strain-Gauge Studies

8. 1 2
A clinical correlation consistent with this pattern of
surface strain is the tendency of some human
beings to form tori in the areas of maximal bending
and torsion (Fig. 4-7).
Clinical Correlation
The largest tori are on the side on which the
individual habitually chews (preferential working
side).

9. Bone Physiology
03

10. The morphology of bone has been well described, but
its physiology is elusive because of the technical
limitations inherent in the study of mineralized tissues.
Accurate assessment of the orthodontic or orthopedic
response to applied loads requires time markers (bone
labels) and physiologic indexes (DNA labels,
histochemistry, and in situ hybridization) of bone cell
function.
Assessment Challenges

11. Systematic investigation with these advanced methods has defined
new concepts of clinically relevant bone physiology.
New Concepts

12. Specific Assessment Methodology
04

13. Physiologic interpretation of the response to applied loads requires
the use of specially adapted methods:
•Mineralized sections are an effective means of accurately
preserving structure and function relationships.
•Polarized light birefringence detects the preferential orientation of
collagen fibers in the bone matrix.
•Fluorescent labels (e.g., tetracycline) permanently mark all sites of
bone mineralization at a specific point in time (anabolic markers).
•Microradiography assesses mineral density patterns in the same
sections.
•Autoradiography detects radioactively tagged precursors (e.g.,
nucleotides and amino acids) used to mark physiologic activity.
•Nuclear volume morphometry differentially assesses osteoblast
precursors in a variety of osteogenic tissues.
•Cell kinetics is a quantitative analysis of cell physiology based on
morphologically distinguishable events in the cell cycle.
•Finite element modeling is an engineering method of calculating
stresses and strains in all materials, including living tissue.
Methods Used

14. Classification of Bone Tissue
05

15. 2
3
4
1
Woven bone varies considerably in
structure. However, it is relatively
weak, disorganized, and poorly
mineralized.
Woven bone serves a crucial role in
wound healing by:
•Rapidly filling osseous defects,
•Providing initial continuity for
fractures and osteotomy segments,
•Strengthening a bone weakened
by surgery or trauma.
Woven bone is not found in the
adult skeleton under normal,
steady-state conditions.
Types of Bone/Woven Bone
The first bone formed in response
to orthodontic loading usually is the
woven type.

16. Types of Bone/Lamellar
Bone
When new
lamellar bone is
formed, a portion
of the mineral
component is
deposited by
osteoblasts
during primary
mineralization.
In contrast to
woven bone,
lamellar bone is a
strong, highly
organized, well-
mineralized
tissue, making up
more than 99% of
the adult human
skeleton.
Secondary
mineralization,
which completes
the mineral
component, is a
physical process
(crystal growth)
that requires
many months.

17. Composite bone is an osseous
tissue formed by the
deposition of lamellar bone
within a woven bone lattice,
called cancellous compaction.
This process is the quickest
means of producing relatively
strong bone and usually is the
predominant osseous tissue
for stabilization during the
early process of retention or
postoperative healing.
Types of Bone/Composite
Bone

18. Bundle bone is a functional adaptation of lamellar
structure to allow attachment of tendons and
ligaments.
Types of Bone/Bundle Bone
Perpendicular striations, called Sharpey fibers, are the
major distinguishing characteristics of bundle bone.

19. 06
Skeletal Adaptation

20. 2
1 Bone remodeling is a coupled sequential process of bone
resorption followed by bone formation.
Bone remodeling occurs both in cortical and trabecular bone
compartments of the skeletal system.
Bone Remodeling

21. Bone modeling is a distinct
process from bone
remodeling and results in a
change in shape and size.
Bone Modeling
It is an uncoupled process
where bone resorption and
formation are not linked or
coupled in a sequential
manner.

22. Bone Metabolism
07

23. Overview
Bone is the primary calcium reservoir in the body. About 99% of the
calcium in the body is stored in the skeleton.
Maintenance of serum calcium levels is essential for nerve
conductivity and muscle function.

24. Endocrinology
Peptide hormones bind receptors at the cell surface and may be
internalized with the receptor complex, while steroid hormones
pass through the plasma membrane to bind receptors in the
nucleus.

25. Positive calcium balance normally occurs during the growing period and for about 10 years thereafter.
Metabolic States

26. 08
Conclusion

27. Conclusion
A thorough understanding of osseous structure and function is
fundamental to patient selection, risk assessment, treatment
planning, and retention of desired dentofacial relationships.

28. Thank You