Periodontal tissues Flashcards
what is the periodontium?
tissues surrounding and supporting the teeth
what is the function of the periodontium?
hold the tooth in its socket
absorb load-bearing forces
defensive barrier from oral environment threat
what is the barrier between the oral environment and the body tissues?
junctional epithelium
what are the two types of cementum?
acellular and cellular
what are the basic functions of cementum? and what causes deposition of cementum?
cement root into the socket
cover root dentine
provide attachment for some PDL
it’s laid by cementoblasts.
what is acellular cementum?
no cells present
adjacent to root dentine
first formed (primary)
what is cellular cementum?
secondary formed
apically and in root furcations
cells within (cementocytes etc.)
what is acellular extrinsic fibre cementum?
contains collagen fibres from PDL that cross and attach to cementum (Sharpey’s fibres)
cervical 2/3 of root
what is cellular intrinsic fibre cementum?
no Sharpey’s fibres
intrinsic parallel collagen fibres with no role of attachment
what cells make up the PDL?
fibroblasts cementoblasts cementocytes osteoclasts epithelial cells defence cells
what 3 nerve types are in the PDL?
sensory mechanoreceptor
nociceptor
autonomic sensory
function of sensory mechanoreceptor nerves in the PDL?
alpha-beta and alpha-delta
- rapidly or slowly adapting
- sense loading forces
- proprioceptors for chewing control
function of nociceptor nerves in the PDL?
alpha-delta and Alpha-C
protective reflexes
inhibit jaw elevator motor neurones
what is the function of autonomic (sympathetic) nerves in the PDL?
blood vessel control - vasoconstritction
what is the blood supply to the PDL?
superior and inferior branch of the alveolar artery
what are the principle fibre groups?
alveolar crest
horizontal
oblique
apical
inter-radicular
where would inter-radicular crest fibres be found?
between roots and alveolar bone in multi-rooted teeth only
where would horizontal fibres be found?
third-most cervical of the PDL. Near the base of the root.
where would oblique fibres be found?
second-most cervical. Below alveolar crest. runs for the majority of the root.
where would apical fibres be found?
apically.
by the root tip and slightly inter-radicular
what are transseptal fibres?
between teeth above the interdental septum.
where would alveolar crest PDL be found?
joining most cervical aspect of the tooth with top of the interdental septum.
