Histopathology of periapical disease

Question 1

look at slides for histology pics

Answer 1

look at slides for histology pics

Question 2

Which periodontal fibres insert into alveolar bone?

Answer 2

Sharpey’s fibres

run obliquely across PDL space and insert into bone to anchor tooth within socket

Question 3

PDL contains epithelial remnants of Hertwig’s root sheath called

Answer 3

Rest cells of Malassez

Question 4

What are rest cells of Malassez

Answer 4

epithelial remnants of Hertwig’s root sheath in PDL

Question 5

Lamina dura

Answer 5

Thin layer of cortical bone outlining PDL space, seen as white gap on radiograph
Can change path if there is a periapical disease

Question 6

Classification of periapical disease: inflammatory

Answer 6

Periapical periodontitis

Question 7

Classification of periapical periodontitis: reactive

Answer 7

‘Osteosclerosis’
Hypercementosis
Ankylosis
Cemento-osseus dysplasia

Question 8

Classification of perapical periodontitis: neoplastic

Answer 8

Benign cementoblastoma

Question 9

Perapical periodontitis

Answer 9

Almost always arises as consequence of pulp death due to caries
May be traumatic (e.g. blow to tooth)

Question 10

Periapical periodontitis: aetiology

Answer 10

Infection (bacterial)
-via root canal (caries)
-via periodontium (e.g. pocket)
Trauma
-physical: direct blow, high filling, malocclusion, bruxism
-chemical: via root canal
-mechanical: root filling

Question 11

Symptomatic periodontitis

Answer 11

Non-vital tooth –> symptomatic (acute) PP –> acute periapical abscess –> acute alveolar abscess –> cellulitis or chronic abscess
Can become chronic, chronic can become acute

Question 12

Acute periapical abscess

Answer 12

Bacteria
-mixed anaerobes 
-root canals or peri-apex
Primary abscess
Radiographic changes

Question 13

Symptomatic periapical periodontitis

Answer 13

Confined to periapical space
Localisable pain
Tooth elevated 
Little radiographic change
May be transient or persistent

Question 14

Spread of infection

Answer 14

Tracking of pus
-PDL
-root canal (if open)
-through bone (sinus formation)
Influence of anatomy 
-antrum
-muscle attachments
-soft tissue (cellulitis)
Bone - osteomyelitis

Question 15

Osteomyelitis

Answer 15

Rare
Pxs on bisphosphonates
Pxs who have had radiotherapy

Question 16

Where may an abscess on an upper tooth drain to

Answer 16

Maxillary sinus
From central incisor --> infraorbital region
Soft tissues of cheek
Nasal passage
Intraoral
Palate

Question 17

Sinus tract

Answer 17

Alveolar abscess - chronic
Discharge intraorally
Cyclical symptoms as it fills up, then discharges

Question 18

Where may an abscess on a lower tooth drain to

Answer 18

Intraoral
Lower incisor –> the chin
Mandible
Floor of mouth

Question 19

Periapical granulomas

Answer 19

Mass of inflamed fibrous CT at base of apex of tooth
Granulation tissue
Loss of bone and replacement
Fibroblasts, macrophages, blood supply

Question 20

Periapical granuloma: histology

Answer 20

Fibrous capsule
Granulation tissue
Inflammation
-lymphocytes, plasma cells, macrophages, occasional neutrophils
Epithelium - rest of Mallasez may proliferate
Bone resorption: osteocalsts

Question 21

What can periapical granuloma lead to

Answer 21

Radicular cyst

Question 22

Cysts of the jaws - odontogenic

Answer 22

Inflammatory
-radicular (most common)
-paradental
Developmental (a lot of types)

Question 23

Radicular cyst

Answer 23

Arise in PDL from epithelial rests of Malassez as result of inflammation following death of pulp
Always associated with non-votal tooth

Question 24

Types of radicular cysts

Answer 24

Apical: at apex of tooth associated with opening of root canal
Lateral: at side of tooth associated with lateral branch of root canal
Residual: radicular cyst which has persisited after extraction of associated tooth

Question 25

Stimulus for proliferation of cyst

Answer 25

Inflammation

Apical granuloma –> radicular cyst –> periodontitis –> pericoronitis

Question 26

Pathogenesis - radicular cyst

Answer 26

Caries –> non-vital pulp –> apical granuloma –> proliferating odontogenic epithelium –> cyst

Question 27

Radicular cysts: histology

Answer 27

Wall (usually fibrous CT)
Lining (mostly epithelial lining)
-proliferative
Lumen filled with fluid and some cellular debris
-plasma cells
-antibodies
-cholesterol accumulation (from cell walls), seen as cholesterol clefts

Question 28

Osteosclerosis

Answer 28

Rarefying osteitis (loss of bone): clinically more acute - radiolucent
Focal sclerosing osteitis (sclerotic bone, more dense): ill-defined periapical radiopacity

Question 29

Hypercementosis

Answer 29

Common - may be age related
Reactive change caused by:
-loss of function - tooth ‘overgrows’ (unerupted teeth)
-inflammation (in a granuloma or mobile teeth with periodontitis)
-Paget’s disease
-idiopathic

Question 30

Hypercementosis histology

Answer 30

Thick layer of cementum around root which is indistinguishable from bone

Question 31

Ankylosis

Answer 31

Hypercementosis obliterates PDL and fuses with alveolar bone

Question 32

Cemento-osseus dysplasia

Answer 32

Reactive lesions
Age 30-50
Often females
Multiple radiopacities
-around tooth roots
-in edentulous areas
Composed of irregular trabeculae of woven bone and cementum in fibrous stroma (fibro-osseus)

Question 33

Florid cemento-osseus dysplasia (Gigantiform cementoma)

Answer 33

Often in edentulous areas
Irregular radiopacities
Masses of fused bone and cementum-like tissue
Reactive, 'scarred bone'
Calcified bodies which fuse into a mass

Question 34

Cementoblastoma

Answer 34

Benign neoplasm
Age 10-40
Radiopaque lesion attached to tooth root
Usually mandibular molar teeth
Composed of
-sheets of cementum and osteoid
-many plump 'osteoblasts'
Resembles osteoblastoma