normal periodontium2 :) Flashcards
components of the periodontium
cementum
alveolar bone
periodontal ligament
gingivae
alveolar bone
forms tooth socket and attachment of PDL
periodontal ligamnet
connects cementum to alveolar bone and gingival
cementum
part of tooth
functions as part of periodontal support
what do the cells of PDLdo
maintain and repair alveolar bone and cementum
- reservoir where bone/cementum cells are derived
effects of stress on tooth of PDL
heavy stress leads to thicker PDL
functionless tooth PDL is thin
what does the PDL consist of
see lec for histology view
fibres - collagen arranged in bundles, attached to gingivae
ECM
cells
other cells within the PDL
undifferentiated ectomesencymal cells
epithelial cell rests (remnants of epithelial sheath)
other connective tissue cell types (macrophages, mast cells_
what can epithelial cell rests appear as
isolated groups of cells or network of cells
close to cementum
what colour do the fibres of PDL stain with connective tissue
brown
fibres in PDL
principle horizontal transeptal apicla interradicular alvelodental dentogingival
gingivae
part of oral mucosa that surrounds tooth and covers alveolar ridge
what does the gingiva do
protect the underlying tissues from oral enviroment
- tooth dependant
what does healthy gingiva look like
pink
firm
scalloped
distinct zones of gingiva
marginal gingiva
attatched gingiva
gingival margin
forms a cuff around neck of tooth
surfaces of the gingival marign
outer surface - keratinsed
inner - non keratinised
gingival papilla
cone shaped between teeth
- papilla fills the space in the interdental embrasure apical to the contact point
- smooth surface
functional mucosa
extends from free gingival groove to mucogingival junction where it meets the alveolar mucosa
mucoperiosteum
tightly bound to underlying alveolar bone
stippled appearance
widest in incisor region
gingiva
contains soft connective tissue and connective tissue of PDL
- collagen fibres insert int alveolar bone or cementum
what forms collagen fibres
fibroblasts
what do the gingival fibres do
keep the tooth in place
run into the soft tissue firmly attaching the gingiva to necks of teeth
groups of gingival fibres
dentogingival
alveologingival
circular
trans septal
dentogingival fibres
from cervical cementum to corium (lamina propria)
alveologingival
from alveolar crest (tip of bone) and extend into corium (CT)
circular
encircle tooth
trans septal GINGIVAL
extend interproximally between adjacent teeth
interdental gingiva
cocave
- site of initial lesion in gingivitus
gingival cuff
circular fibres
juncitional epithelium crevicular fluid
junctional epithelium
lies against enamel and extends to CEJ(cementoenamel junction)
fucntion of the periodontium
attachment and support
nutritive
sensation
what do all components of the periodontium do
absorb masticatory forces
what happens to blood under masticatory forces
compressed as fibre bundles tensed
blood displaced into bone through volkmanns canals
what happens to the ECM under masticatory forces
hydrophilic
cannot be compressed
- pushes out alevolar walls to increase tension in fibre groups
nerves in PDL
free nerve ending
encapsulated endings
what do encapsulated nerve endings to
mechanoreceptors
what do free nerve endings transmit
pain
explain what mechanoreceptors do
impulses to mesnephalic nucleus of trigeminla nerev
- this inhibits muscles of mastication therefore stop action
what are light forces on the PDL cushioned by
intravascular fluid that is forced out of blood vessels
what are moderate forces on PDL taken up by
extravascular fluid that is forced out of the periodontal ligament space into the adjacent marrow spaces
what are heavier forces on PDL taken up by
principle fibres
What does the remodelling function of the PDL alloq
provides cells that are able to form as well as resorb tissues that make up the attachment apparatus
what does the attached gingiva do
keeps the free gingiva from being pulled away from the tooth
what does cementum do
anchor teeth to alveolar bone via the PDL
- protective layer over dentine
tooth movemnts
eruption and exfoliation
approximate frit
masticatory load
orthodontic tooth movement
what is post eruptive tooth movemtn
maintaining the position of the erupted tooth in occlusion while the jaws continue to grow and compensate for occlusal and proximal tooth wear
what are the 3 categories of post eruptive tooth movemnt
accommodate for growing jaws
compensate for occlusal wear
accommodate for interproximal wear
approxminal drift
all teeth move towards the midline over time
-dependant on degree of wear of contact points between adjacent and no. missing teeth
what may approximate drift lead to
crowding later in life
what forces lead to approximal drift
anterior component of occlusal force
soft tissue pressure pushing onto the teeth
contraction of the transeptal ligament between teeth
orthodontic tooth movement can only occur if
bone resorption occurs in the direction which tooth is being moved
explain orthodontic tooth movemtn
bone respiration occurs in direction of tooth movement
pressure on surface of alveolar bone in direction of movement
causes tension on PD on opposite side of root
causes changes in vascular and neural tissue along the bone and cementum
boen respobtion on on side and bone formation on the other side
what does the tension side(application of orthodontic force) of orthodontic tooth movement look like
PDL taut
bone depostition
what does the pressure side of orthodontic tooth movement look like
PDL slack
no real pattern
bone respobtion
what does too much orthodontic moves lead to
PDL fibres break down faster than replaced
inflammation causes respobtion of root apicies
what is tipping movement and when is it used
pressure on a specific area
to change the occlusion only
(apex not moved)
Bodily movement
root moved in the same direction
compression changes in PDL upon advancing root surface, tension changes in PDL bone and cementum on opposite side
what happens if compression of orthodontics is too great
hyalinisation of PDL
therefore it is colourless
on the compression surface what is responsible
osteoclasts
what is a reversal line
area where deposition starts
appearance of cells on the tension surface
collagen fibres stretched cells orientated in direction of tension - fibroblasts - osteoclasts -cementoblasts
orthodontic tooth movement
tilting body rotation combinations of tipping and rotation intrusion extrusion
what is extrusion
pulling the tooth doen
what happens if a tooth is pulled too far forward
areas of fenestration i.e. hole
what is it called when a tooth is pulled too far out
dehiscence
- leads to gingival recession
where does periodontitis start
at gingival margin with inflammation due to plaque stagnation
biological treatment options of periodontitis
oral hygiene instruction
scaling and RSD
what are the goals of PD therapy
eliminate infmallation
restore lost periodontium (by activating undifferentiated ectomesenchymal cells)
how does the follicle differentiate
source of cementoblasts and fibroblasts
may contribute to alveolar bone
regeneration products
bio-oss
bio-gide
emdogain
bio - oss
natural bone substitute material
bio - gide
membrane bilateral stricture
holds bio oss together
emdogain
makes bony influx in area placed
allows for colonisation, proliferation and differentiation of cells (forms a 3d ECM)
regeneration therapu
regereration of tooth support use protins biological membranes growth factors emdogain bacterial products
