Periodontal tissues

Question 1

what is the periodontium?

Answer 1

tissues surrounding and supporting the teeth

Question 2

what is the function of the periodontium?

Answer 2

hold the tooth in its socket

absorb load-bearing forces

defensive barrier from oral environment threat

Question 3

what is the barrier between the oral environment and the body tissues?

Answer 3

junctional epithelium

Question 4

what are the two types of cementum?

Answer 4

acellular and cellular

Question 5

what are the basic functions of cementum? and what causes deposition of cementum?

Answer 5

cement root into the socket

cover root dentine

provide attachment for some PDL

it’s laid by cementoblasts.

Question 6

what is acellular cementum?

Answer 6

no cells present

adjacent to root dentine

first formed (primary)

Question 7

what is cellular cementum?

Answer 7

secondary formed

apically and in root furcations

cells within (cementocytes etc.)

Question 8

what is acellular extrinsic fibre cementum?

Answer 8

contains collagen fibres from PDL that cross and attach to cementum (Sharpey’s fibres)

cervical 2/3 of root

Question 9

what is cellular intrinsic fibre cementum?

Answer 9

no Sharpey’s fibres

intrinsic parallel collagen fibres with no role of attachment

Question 10

what cells make up the PDL?

Answer 10

fibroblasts
cementoblasts
cementocytes
osteoclasts
epithelial cells
defence cells

Question 11

what 3 nerve types are in the PDL?

Answer 11

sensory mechanoreceptor

nociceptor

autonomic sensory

Question 12

function of sensory mechanoreceptor nerves in the PDL?

Answer 12

alpha-beta and alpha-delta

• rapidly or slowly adapting
• sense loading forces
• proprioceptors for chewing control

Question 13

function of nociceptor nerves in the PDL?

Answer 13

alpha-delta and Alpha-C

protective reflexes

inhibit jaw elevator motor neurones

Question 14

what is the function of autonomic (sympathetic) nerves in the PDL?

Answer 14

blood vessel control - vasoconstritction

Question 15

what is the blood supply to the PDL?

Answer 15

superior and inferior branch of the alveolar artery

Question 16

what are the principle fibre groups?

Answer 16

alveolar crest

horizontal

oblique

apical

inter-radicular

Question 17

where would inter-radicular crest fibres be found?

Answer 17

between roots and alveolar bone in multi-rooted teeth only

Question 18

where would horizontal fibres be found?

Answer 18

third-most cervical of the PDL. Near the base of the root.

Question 19

where would oblique fibres be found?

Answer 19

second-most cervical. Below alveolar crest. runs for the majority of the root.

Question 20

where would apical fibres be found?

Answer 20

apically.

by the root tip and slightly inter-radicular

Question 21

what are transseptal fibres?

Answer 21

between teeth above the interdental septum.

Question 22

where would alveolar crest PDL be found?

Answer 22

joining most cervical aspect of the tooth with top of the interdental septum.