Transcript Chronic PeriodontitisChronic Periodontitis [PPT]

Cellular elements
4 Types
- connective tissue cells (Fb, Cb, Ob)
- epithelial rest cells
-immune system cells
- cells associated with neurovascular
elements
Connective tissue cells
Fibroblast- most common cells in the PDl
- ovoid or elongated cells and exhibit pseudopodia like process
- synthesize collagen and have the capacity to phagocytose old
collagen fib and degrade them by enzyme hydrolysis.
Cementoblast
- They are the cells responsible for secreting the organic
matrix of cementum in the PDL.
Osteoblast
- They are found on the surface of the alveolar bone.
Epithelial rest cells
- Epithelial rest of Malassez are considered as remnants Hertwigs
root sheath which disintegrates during root development.
- Most numerous in apical and cervical areas.
- when stimulated, may participate in the formation of periapical
cyst and lateral root cyst.
Immune system cells
Include – neutrophils, lymphocytes, macrophages, mast cells
and eosinophils.
These cells as well as those associated with neurovascular
elements, are similar to the cells in other connective tissues.
Ground substance
GAG (glycosaminoglycans)
- Hyaluronic acid
- Proteoglycans
GP (glycoproteins)
- fibronectin
- Laminin
Water (70%)
Functions of ground substance
Helps in transportation of water, electrolyte,
nutrients, and metabolites, to and from CT cells,
thus is essential for the maintenance of the normal
function of CT.
PDL may also contain calcified masses called cementicles which
are adherent to detached from root surface.
Cementicles may develop from calcified epithelial rest, around
small spicules of cementum or alveolar bone traumatically
displaced in to PDL, from calcified sharpey’s fib, and from
calcified thrombossed vessels in PDL.
Functions of PDL
1.
2.
3.
4.
5.
Physical
Formative
Remodelling
Nutritional
Sensory
Physical function
1. Provision of soft tissue “casing” to protect the vessel and nerves
from injury to mechanical forces.
2. Transmission of occlusal forces to the bone.
3. Maintenance of gingival tissues in their proper relationship to the
teeth.
4. Resistance to the impact of occlusal forces (shock absorption).
SHOCK ABSORPTION
2 theories-
-Tensional theory
-Viscoelastic system theory
Formative and remodeling function
PDL have the regenerative capacity in providing the cell
lineage namely ob, cb and fb. Thus it help in the formation
and resorption of cementum and bone during physiological
tooth movement and repair of injuries.
Nutritional and sensory function
PDL supplies nutrients to the cementum, bone and gingiva by
way of blood vs and also provide lymphatic drainage.
The PDL is abundantly supplied with sensory nerve fib
capable of transmitting tactile, pressure and pain sensations
by the trigeminal pathway.
There are 4 types of neural terminations are
present in PDL
1. Free ending- which have tree like configuration and carry
pain sensation
2. Ruffinian corpuscles- Mechanoreceptors (in apical areas)
3. Meisners corpuscles- Mechanoreceptors (in midroot
areas)
4. Spindle like receptors- Pressure and vibration receptors/
Homeostasis
With the presence of both formative and resorptive
activity the PDL provides a homeostasis in the tissue
environment.
Blood supply
3 sources1. Apical vs
2. penetrating vs from alveolar bone
3. Anastomosing vs from gingiva
Maxilla- sup alv artery
mandibli- inf alv artery
Venous drainage of PDL accompanies the arterial supply.
Nerve supply
1. Anatomic
2. Sensory
THANK YOU