BIOLOGY OF TOOTH MOVEMENT - srmdentalcollege.ac.in
Transcript of BIOLOGY OF TOOTH MOVEMENT - srmdentalcollege.ac.in
BIOLOGY OF TOOTH MOVEMENT
-DR.SUVETHA. S
Senior lecturer,
Department of orthodontics,
SRM Dental college, Ramapuram.
Compression of PDL at Pressure
site
Stretching of PDL at
Tension site
BONE REMODELLING/ ORTHODONTIC
TOOTH MOVEMENT
Changes in tooth
position during
mastication
Tooth eruption
Migration or drift of tooth
PHYSIOLOGIC TOOTH MOVEMENT
What is physiologic tooth movement?!!!
TOOTH ERUPTION
Blood pressure theory
Hammock
Ligament
Periodontal ligament traction
Root growth
What is tooth eruption ???
The axial movement of the tooth from its developmental position in the jaw to its final
position in oral cavity
Migration or drift of teeth
Mandibular dentition
Mesial/ Distal Occlusal
Maxillary dentition
Mesial and occlusal
Tooth movement during mastication
MASTICATION
Intermittent heavy force for 1 sec
(Range: 1 to 50 kgs)
Fluid is incompressable
Bending of alveolar bone
Sustained heavy force
Pain and displacement of teeth
Histology of orthodontic tooth movement
Frontal resorption
Undermining resorption
Secondary bone remodeling
Optimum orthodontic force
Clinically
Rapid tooth movement & no tooth mobility
No patient discomfort
LAG phase of tooth movement is minimal
Histologically
Vitality maintained
Maximum cellular response
Direct or frontal resorption
Oppenheim & Schwartz – 20-26gm/ Sq.cm
Hyalinization
EliminationGradual shrinkage of PDL fibers
Pycnotic nuclei
Compressed fibers combine to form cell
free mass
Changes in ground substance
Spillage of capillary contents
Osteoclasts in bone marrow and inner bone
surface within 20-30hrs
Clear, eosinophilic and homogenous substanceHyalinization in PDL is reversible !!!
Invasion of cells and blood vessels
Osteoclasts formed in the peripheral intact tissue
Hyalinization during different tooth movements
Controlled tippingUn-controlled tipping
Bodily movement
Phases of tooth movement
BURSTONE
Theories of orthodontic tooth movement
• Pressure- tension theory: Oppenheim & Schwarz
• Fluid dynamic theory: Bien
Vascular stenosis Aneurysm
Bone bending and piezo-electric theory: Farrar
Bone deposition and resorption
Osteoid
Bundle bone
Lamellar bone
DecalcificationOrganic acids
Degradation of matrix
Transport of soluble products to extracellular fluid or blood vascular system
Cathepsin B-1 (lysosomal acid protease)
Orthodontic Force Tranduction
First messengers
(Hormones, Prostagladins,
neurotrasmitters)
Second messengers
(cyclic AMP, GMP and calcium )
Bone remodeling/ Orthodontic tooth
movement
Biochemical reaction to orthodontic tooth movement