DP08 responses of oral tissues to restorative procedures

Question 1

What is allergy?

Answer 1

Immune reaction to an allergen (protein). Type I hypersensitivity reaction including IgE and mast cells in the reaction. Could be type IV like contact eczema which is cell-mediated.

Question 2

What can happen from allergic reaction?

Answer 2

Angio-oedema -> severe facial swelling
Anaphylaxis - immune overaction causing oedema in the glottis and block breathing

Question 3

What things can cause allergic reaction in dental surgery?

Answer 3

Antibiotics, amalgam, latex gloves

Question 4

What can go wrong with local anaesthetic?

Answer 4

Injection into a vessel
Injection into infection
Haematoma
Facial palsy
Needle fracture
Lack of anaesthetic effect
Syncope

Question 5

Why is injection into bloodstream bad?

Answer 5

Vasoconstrictor - bad for heart conditions
Also anaesthetic will not act in the area it is meant to

Question 6

Why is it bad to inject into infection?

Answer 6

Wont work as well due to acidic pH
Bacteria can spread to other areas of the body - puts pressure on it

Question 7

How can LA cause haematoma?

Answer 7

Can damage a blood vessel causing blood acumulation

Question 8

What happens when you drill into a tooth to create a cavity?

Answer 8

Forms a smear layer

Question 9

What does the smear layer consist of?

Answer 9

It is a microthin gelatinous layer of:
- organic material: heat coagulated dentine proteins, saliva, blood, microorganisms
- inorganic material: tooth minerals and contaminants

Question 10

Why do we remove the smear layer?

Answer 10

To increase dentine permeability

Question 11

What factors are involved in pulp reactions from drilling the tooth?

Answer 11

The stronger the stimulus the more pronounced the reaction is
Number of odontoblasts cut
Tubules width
Distance from the pulp
Heat generated

Question 12

What are the different effects of drilling on odontoblasts?

Answer 12

Odontoblast process completely destroyed: dead tracts of Fish
Dentinal sclerosis
Regular/irregular/cellular tertiary dentine
‘wheatsheaving’ of odontoblasts

Question 13

How do dead tracts of Fish present and why?

Answer 13

Very dark as opposed to transparent dentine
Dentinal tubules are empty so light refraction is different

Question 14

How does sclerotic dentine present?

Answer 14

Sclerotic dentine is very transparent

Question 15

What is sclerotic dentine?

Answer 15

Internal tubules diameter narrows down and completely obliterates

Question 16

When does the tooth produce tertiary dentine?

Answer 16

Pulp produces tertiary dentine in response to injury or damage
Tubules that have been cut produce extra

Question 17

What does rate of deposition of tertiary dentine depend on?

Answer 17

Rate of deposition depends on intensity of the injury

Question 18

What is the difference between reactionary and reparative tertiary dentine?

Answer 18

Reactionary - formed by existing odontoblasts
Reparative - formed by new odontoblast-like cells, often differentiated from dental pulp stem cells

Question 19

What is ‘wheatsheaving’ of odontoblasts?

Answer 19

Fluid accumulation in the odontoblast layer, pushing them to the side

Question 20

What are the issues that can arise from affected odontoblasts?

Answer 20

Pulp hyperaemia
Acute pulpitis
Pulp abscess
Chronic pulpitis

Question 21

What is pulp hyperaemia?

Answer 21

Vasodilation of the pulp - reversible if removed.
(11 degrees above body temp can damage odontoblasts and kill pulp)

Question 22

How might filling materials cause injury to the tooth?

Answer 22

Chemical irritation of pulp
Exothermic reactions
Heat transmission
Galvanic current

Question 23

What are some poor techniques during fillings that can cause iatrogenic damage?

Answer 23

Matrix band injuries to gingiva - breaking epithelial attachment to tooth
Impression materials left in gingival crevice
Poorly contouring of restoration leading to recurrent caries and gingivitis
Poor occlusal reconstructions - forces applied unevenly to teeth might cause apical periodontitis
Amalgam tatto (distinguish from malignant melanoma)

Question 24

How can impression taking cause iatrogenic damage?

Answer 24

Wrong size trays causing mucosal injury
Material too fluid - respiratory obstruction
Burns from hot materials

Question 25

How can endo/root instrumentation cause iatrogenic damage?

Answer 25

Overinstumentation/filling of the wools can cause periapical lesions from bacteria entering the apex Underinstrumentation will leave the current infection Broken instruments in root canal

Question 26

How can perio cause iatrogenic damage?

Answer 26

Broken instruments during root planing

Question 27

How can dentures cause iatrogenic damage?

Answer 27

Poor fitting dentures - can cause fibroepithelial hyperplasia Poorly designed connectors and clasps - gingival injuries, tooth movements, food packing

Question 28

What are the different types of biopsy?

Answer 28

* Excisional biopsy – whole lump is removed (excised) * Incisional biopsy – portion of the lump is removed * Extemporary biopsy – performed in the operating theatre (When going for an operation, you find a lump that is unexpectedly there. Tiny biopsy of the lump is taken and examined while the patient is still in operating theatre, trying to diagnose) * Exfoliative cytology (smears) * Fine needle aspiration (FNA) biopsy

Question 29

What biopsy precautions should you take?

Answer 29

* Avoid biopsy of vascular lesions * Avoid biopsy of obvious lesions * Biopsy should be representative of lesion – e.g., ulcerated lesion needs the ulcerated part and surrounding tissues * Always include some normal tissue * Tissues not distorted by handling * Tissue should be properly fixed – chlorhexidine is not a fixative * Avoid use of laser/electrical scalpel – this will burn the tissue when removing * Avoid coating the lesion with chemicals – sometimes they react with the dyes that you stain the sections with, so staining might not happen there