Chapter 5 - periodontal anatomy Flashcards

1
Q

what does a normal periodontium consist of?

A
  • the gingiva
  • bone
  • cementum
  • the PDL
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2
Q

healthy tissues can differ in appearance why?

A

as each individual will have a different

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3
Q

what are the 2 components of the gingiva?

A
  • the attached gingiva

- the alveolar mucosa

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4
Q

what does healthy attached gingiva look like?

A

frames the crowns of the teeth buccal & lingual/palatal aspects

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5
Q

what is the purpose of the attached ginigva?

A

to provide a strong PROTECTIVE cuff around the neck of the tooth that keeps food away from delicate epithelial attachment

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6
Q

what is the attached ginigva covering?

A

the bony attachment to the teeth

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7
Q

in caucasians what colour/texture is the attached gingivae?

A

coral pink colour with light stippling that looks like orange peel

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8
Q

why does the attached gingiva have a stippling appearance?

A

the attached gingvae is a TRUE MUCOPERIOSTEUM (and the stippling corresponds to the attachment of the epithelium to the periosteum)

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9
Q

normally how thick is gingival tissue?

A

2-3mm

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10
Q

normally what width is the gingival tissue?

A

1-5mm

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11
Q

what happens to the width of the gingival tissue through age?

A

it thickens

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12
Q

what is the free gingival margin and what does it look like?

A

where the gingivae terminates at the coronal aspect of the tooth.

It is scallop shaped to contour the tooth

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13
Q

what is the junction called at the apical aspect of the attached gingiva? what is the junction separating?

A

the mucogingival junction seperates the attached ginigva from the looser more flexible alveolar mucosa

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14
Q

why is the “free’ gingival margin called free?

A

because it is not attached to the tooth on its inner (crevicular) aspect.

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15
Q

instead of attachment of the free gingival margin to the tooth what is there?

A

a gingival crevice

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16
Q

how deep is the gingival crevice? where is the deepest part?

A

1-3mm

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17
Q

what is at the base of the gingival crevice?

A

the junctional epithelium

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18
Q

what is the junctional epithelium?

A

a 1mm thick band of epithelial cells that attach the gingivae to the cementum. It is located at the base of the gingival crevice

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19
Q

what does the connective tissue contain?

A

collagen fibres that are arranged in groups

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20
Q

what is the biological width of the gingiva made up of? 3 things

A
  • gingival crevice
  • connective tissue attachment
  • junctional epithelium
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21
Q

what happens if a restoration margin is placed beyond the gingival crevice in the area attached by junctional epithelium or connective tissue?

A

there will be persistent inflammation which can be both uncomfortable (pain and bleeding) and unsightly due to swollen and discoloured tissues

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22
Q

what is the gingival papilla?

A

the attached gingiva forming a triangular papilla on both the buccal and the lingual aspect between the teeth

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23
Q

how does the ID papilla differ between the anterior and posterior teeth?

A

anterior teeth = more pyramid shaped

posterior teeth = flatter than anteriors

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24
Q

what is the valley between the 2 interdental peaks of the papilla called?

A

the interdental col

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25
Q

define keratin

A

a tough fibrous insoluble protein

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26
Q

where in the gingival tissues can you find keratin?

A

the attached gingiva outer surface (overlying the connective tissue

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27
Q

what is the connective tissue in the attached gingivae known as?

A

lamina propria

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28
Q

what is the periosteum?

A

a richly vascular layer of dense connective tissue

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29
Q

why is it difficult to tell the difference between periosteum and bone?

A

because at the deepest layer of periosteum there are osteoblasts and also some periosteum fibres embedded in bone

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30
Q

how does the gingiva derive most of its blood supply from?

A

via small branches of the inferior or superior dental arteries that are on the surface of the PERIOSTEUM

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31
Q

what are gingival periodontal fibres?

A

randomly arranged collagen fibres that are closely associated with attachment of the gingivae to the tooth

32
Q

there are 4 main gingival periodontal fibres. what are they called?

A
  1. dentogingival fibres
  2. dentoperiosteal fibres
  3. circular fibres
  4. transeptal fibres
33
Q

where are dentogingival fibres found?

A

they are embedded in the cementum in the connective tissue attachment area

they fan out in a coronal direction towards the free gingival margin

34
Q

where are the dentoperiosteal fibres located?

A

they are embedded in the same area as the dentogingival fibres but turn in an apical direction towards the root of the tooth

35
Q

how are circular fibres arranged?

A

like a ring round the tooth

36
Q

where are transeptal fibres found?

A

they are embedded in the cementum of adjacent teeth and run above the bone crest

37
Q

what happens to all these collagen fibres during gingivits and periodontitis?

A

they are damaged or destroyed

38
Q

what is main responsibilities of the collagen gingival periodontal fibres? and what apperance do they give in health?

A

to provide a tight gingival cuff around the tooth

stippling effect in health

39
Q

what clinical signs of gingivitis or periodontitis are caused by the damage/destruction to the collagen gingival fibres?

A
  • smooth (glazed appearance) with loss of stippling due to inflammation
  • teeth become looser as less tight gingival cuff
40
Q

what happens to the collagen fibrres following non-surgical periodontal treatment and what is the clinical result?

A

regrowth of the collagen fibres results in a tighter gingival cuff

41
Q

describe what happens to the gingival collagen fibres when a surgical flap is raised? what happens after healing and how long does healing take?

A

there is severing of the circular and transeptal fibres which causes the teeth to become looser but as healing occurs the teeth become less loose and have a tighter gingival attachment - this takes approx 3-4 months

42
Q

give characteristics of the alveolar mucosa? 6

A
  • softer
  • more flexible than attached mucosa
  • much thinner layer of keratin
  • continuous with the mucosa of the buccal and lingual sulcus
  • smooth shiny surface
  • darker red colour
43
Q

what is the name of the bone that supports the teeth?

A

the alveolar bone

44
Q

when does the alveolar bone grow?

A

as the teeth erupt into the mouth forming the various alveolus of themaxilla and mandible

45
Q

how exactly does the alveolar bone support the teeth?

A

it absorbs and distributes the occlusal forces

46
Q

what is the thin layer of compact bone that is at the wall of each tooth socket called?

A

cortical bone

47
Q

where is cancellous bone found and how does it differ from cortical bone?

A

cancellous bone is found in the areas between the tooth sockets and is much more sponge like (more spaces) than cortical bone.

48
Q

what are sharpey’s fibres?

A

the ends of the PDL fibres

49
Q

where are sharpey’s fibres embedded into?

A

the alveolar bone of the socket wall and the cementum

50
Q

bone is constantly remodelling in response to ….

A

functional changes and needs

51
Q

bone is a …. tissue

A

dynamic

52
Q

define cementum

A

the calcified surface tissue covering the dentine of the root of the tooth

53
Q

cementum has a similar structure to bone but how does it differ to bone? 4 things

A
  • no blood supply
  • no nerve supply
  • does not remodel
  • is more resistant to resorption than bone
54
Q

when does cementum resistance to wear come in handy and how?

A

when carrying out orthodontic treatment

it allows the alveolar bone resorption in response to controlled applied pressures with minimal root resorption as cementum does not resorb at same rate as bone (if they did then the root would resorb as the bone did)

55
Q

what does cementum do in terms of attachment?

A

it allows attachment of the PDL sharpey’s fibres the root of the tooth (they can then attach to the alveolar bone)

56
Q

what does the cementum do in terms of protection?

A

1 - it contributes to the process of repair once the root surface has been damaged

2 - it caries out cementosis

57
Q

what is cementosis?

A

the cementum increases in thickness at the apical area in response to occlusal attrition which protects the underlying dentine

58
Q

what does cementum do instead of remodelling?

A

it gradually increases thickness with age by deposition of new layers (unlike remodelling which occurs in response to functional changes)

59
Q

what is it called when cementum thickens too much?

A

hypercementosis

60
Q

connective tissue consists of what?

A

ground substance

61
Q

what are the 4 components of ground substance?

A
  • fibroblasts
  • macrophages & neutrophils
  • lymphocytes
  • fibrous tissue
62
Q

what are fibroblasts?

A

collagen producing cells

63
Q

what are macrophages?

A

DEFENCE CELL

mobile white blood cell (large phagocytic -foreign body ingesting - cell)

64
Q

what is a neutrophil?

A
DEFENCE CELL
a granulocyte (filled with microscopic granules that contain enzymes and digest micro-organisms)
65
Q

what is a lymphocyte

A
INVOLVED IN IMMUNE RESPONSE
small leucocyte (T-cells or B-cells) that are involved in the immune system and especially found in the lymphatic system
66
Q

what do B-cell lymphocytes do?

A

they produce antibodies against bacteria & toxins

67
Q

what do T-cell lymphocytes do?

A

they actively destroy body cells that have been taken over by viruses or cancer for example

68
Q

what are the 2 components of fibrous tissue?

A
  1. elastic elastin fibres

2. non-elastic collagen fibres

69
Q

The PDL inserts into where at each end?

A

the cementum and the alveolar bone

70
Q

what are sharpey’s fibres made of?

A

collagen

71
Q

what property of the PDL fibres allow is to fulfil its function and what is the function?

A

they are elastic fibres in nature which allows them to EXTEND in response to occlusal loading.

72
Q

why is it good to have PDL fibres that can extend? ie what is the PDL’s functions

A

extension acts as a cushion for tooth allowing it to:

  • absorb functional forces
  • reduce likelihood of damage to the supporting structures
  • make chewing more comfortable
73
Q

What makes the PDL so sensitive?

A

in between the PDL fibres there is connective tissue which in it has the blood vessels that supply the attachment apparatus

74
Q

how does PDL pain present from Pulpal pain?

A

the patient will be able to accurately localise the pain as apposed to pulpal pain that sometimes can be very generalised and difficult to isolate

75
Q

how does the gingivae get its nerve supply ?

A

from branches of the trigeminal nerve