L11 Periapical Disease

Question 1

What is the most likely cause of periapical periodontitis?

Answer 1

Pulp necrosis

Question 2

What is periapical periodontitis?

Answer 2

Inflammatory changes in the periapical part of the PDL. May cause adjacent bone resorption.

Question 3

What are the causes of pulp necrosis?

Answer 3

• Trauma
• Bacteria (caries)
• Restorative procedures
• Endodontic treatment (instruments or chemicals passing beyond the root apex to periradicular tissues)

Question 4

How does pulp necrosis affect the periapical tissues?

Answer 4

Diffusion of cells, bacteria and bacterial products from the pulp to the periapical tissues.
Triggers an inflammatory response as it damages cells in the adjacent cementum, PDL and bone.

Question 5

Describe the initial stages of periapical disease.

Answer 5

• Initial acute inflammatory reaction
• Vascular dilation, oedema, neutrophil exudation
• Tooth may be TTP (tender to percussion)
• Tooth may be extruded from socket

Question 6

Describe the second stages of periapical disease.

Answer 6

• Continued diffusion of damaging material from apical formaen, lesion progresses
• The rate and form of lesion progression depends on host resistance and the nature and severity of damaging agents

Question 7

What are the 3 major forms of periapical disease?.

Answer 7

• Acute periapical periodontits
• Periapical granuloma
• Acute periapical abscess

Question 8

Describe the presentation of acute periapical periodontits.

Answer 8

• May be symptomless, painful, TTP, slightly extruded
• Radiologically may be slight widening of ligament space and loss of definition of lamina dura
• Histologically: acute inflammation, oedema and neutrophil infiltration into PDL

Question 9

What are the 3 possible outcomes of acute periapical periodontitis?

Answer 9

• Resolution (if cause of condition is removed)
• Periapical granuloma (if it follows a chronical course)
• Acute periapical abscess (if it follows an acute suppurative course)

Question 10

What is the alternative name for a periapical granuloma?

Answer 10

Chronic periapical periodontitis.

Question 11

Briefly outline a periapical granuloma.

Answer 11

• Slow progression
• There is resorption of periapical bone
• Lost bone replaced with granulation tissue
• Rarely larger than 5-6mm in diameter

Question 12

Describe the clinical presentation of a periapical granuloma.

Answer 12

• Usually symptomless

- May be vague symptoms of mild discomfort

Question 13

Describe the radiological presentation of a periapical granuloma.

Answer 13

• Appears as a round radiolucent area at tooth apex
• Loss of lamina dura at apex
• May be bone sclerosis at the periphery (white outline)

Question 14

Describe the histological presentation of a periapical granuloma.

Answer 14

• Granulation tissue
• Evidence of tissue damage and repair
• Fibrous stroma
• Many thin walled capillaries
• Inflammatory cell infiltrate (lymphocytes, plasma cells, macrophages)
• Many foam cells
• May be some collections of neutrophils
• Often see anastamosing strands and islands of squamous epithelium, epithelium derived from Rests of Malassez (non-keratinised)

Question 15

What is an acute periapical abscess also known as?

Answer 15

A dentoalveolar abscess

Question 16

Briefly outline an acute periapical abscess.

Answer 16

• May develop either from acute periapical periodontits, or follow on from a periapical granuloma or cyst
• Tissue damage with large numbers of neutrophils
• Neutrophils killed and liquefy (pus)

Question 17

Describe the radiological presentation of a dentoalveolar abscess.

Answer 17

• Little change, unless the abscess arises from a pre-existing lesion

Question 18

Describe the histological presentation of a dentoalveolar abscess.

Answer 18

• Central pus filled cavity (dense infiltration of neutrophils)surrounded by granulation tissue and fibrous tissue
• Mixed infection (4-9 species of facultative and strictly anaerobic bacteria)

Question 19

What are the possible complications of an acute periapical abscess?

Answer 19

• Abscess can track through bone to the soft tissues and drain
• Drain through the gingival sulcus
• Drain through a sinus
• Spread to soft tissue spaces of the head and neck
• Cellulitis, osteomyelitis, periostitis, cavernous sinus thrombosis

Question 20

Describe how a periapical abscess can drain through a sinus.

Answer 20

• Abscess tracks through bone to reach surrounding soft tissues
• A parulis fistula forms on the gingivae, providing a tract out into the oral cavity
• Pus drains, reduction in pressure, reduction in symptoms

Question 21

Describe how a periapical abscess can drain through an extraoral sinus.

Answer 21

• Abscess can track through bone to soft tissue
• Produces an extra oral discharging sinus e.g. on the mandible
• Pus discharges, pressure reduces, symptoms resolve

Question 22

Describe what happens when a dentoalveolar abscess spreads to the soft tissue spaces of the face and neck.

Answer 22

• Extremely serious
• Obvious swelling
• Requires surgical intervention: incision and draining

Question 23

What is osteomyelitis, cellulitis, periostitis and cavernous sinus thrombosis?

Answer 23

• Osteomyelitis: infection and inflammation of the bone
• Cellulitis: infection of the skin and adipose tissue
• Periostitis: inflammation of the periosteum of the bone
• Cavernous sinus thrombosis: blood clot in the cavernous sinus