Management of Deep Caries

Question 1

what is considered “deep caries”?

Answer 1

• caries that extend to the pulpal third of dentine

Question 2

when spotting deep caries what should be looked out for?

Answer 2

• shadowy patch on tooth surface, usually reveals a deep cavity

Question 3

what are the 2 layers of carious dentine? describe each layer

Answer 3

1. outer zone: demineralized, denatured, infected and not remineralizable (infected zone)
2. inner zone: dentine is demineralized, minimally infected, collagen fibres still intact, dentine remineralizable (affected zone)

Question 4

occlusal caries: lesions radiographically visible extend to where? how infected are they?

Answer 4

• lesions radiographically visible extend down to middle third of dentine and beyond
• heavily infected

Question 5

proximal lesions: how different is the clinical depth and radiographical depth of the lesion?

Answer 5

• lesions are deeper clinically than they appear radiographically.

Question 6

in deep caries, where do bacteria within lesion obtain substrate? x2

Answer 6

• oral cavity

- possibly pulp: tissue glucose

Question 7

liquefaction foci: formed by?

Answer 7

formed by breakdown of dentinal tubule

Question 8

which zone of caries need to be removed?

Answer 8

the outer zone only

Question 9

what are 3 issues brought about by deep caries?

Answer 9

• complete caries removal run risk of damage to pulp dentine complex
• pulpal exposure
• loss of pulp vitality

Question 10

what are 2 pulpal responses to caries?

Answer 10

• tubular sclerosis

- reactionary dentine formation

Question 11

reactionary dentine formation: regularity and quality depend on? how so?

Answer 11

• regularity and quality depend on how rapidly the lesion progresses:
• slow progressing lesion: more regular with tubular structure

Question 12

what are the aims of the pulpal responses to caries?

Answer 12

• reduce diffusion of bacterial byproducts towards pulp, therefore slowing down rate of progression
• balance between rate of lesion progression and pulpal responses

Question 13

how does pulpal inflammation vary with the distance of the lesion from the pulp?

Answer 13

• lesion more than 1mm from pulp: little pulpal inflammation

- lesion less than 0.5mm from pulp: inflammatory change

Question 14

what are the principles of caries removal? x5

Answer 14

• gain access to caries: high speed
• remove peripheral caries: slow speed
• pulpal caries removal: excavator
• what materials to use?
• modify cavity design if necessary

Question 15

indirect pulp cap: process?

Answer 15

excavate pulpal caries
until firm, leathery stained dentine reached
- line with setting calcium hydroxide

Question 16

direct pulp cap: when to consider?

Answer 16

if the pulp is exposed at final excavation, consider direct pulp cap with setting calcium hydroxide
*only in small exposure, in absence of symptoms of pulpitis

Question 17

what is stepwise excavation?

Answer 17

caries removed over 2 appointments, 6-12months apart

Question 18

stepwise excavation: what happens on the first visit?

Answer 18

• remove superficial layer of infected necrotic dentine
• ensure peripheral caries removal complete
• place calcium hydroxide lining and glass ionomer
• leave for 6-12months for pulp dentine complex reactions

Question 19

stepwise excavation: what happens on the second visit?

Answer 19

re-clean cavity

restore

Question 20

what changes after the first excavation and before the final excavation?

Answer 20

• colony forming unit (CFU) decreases
• dentine color darkens
• dentine hardens
• sites of excavation dried up

Question 21

microbiological changes after before final excavation?

Answer 21

• decrease in microbial load
• reduction in microbial diversity
• reduction in nutrient amount and complexity
• pulpal nutrient decrease in time with pulp dentine complex reactions

Question 22

how to restore teeth permanently? what are the two methods of restoration and what do each involve?

Answer 22

• occlusal restoration: glass ionomer and composite sandwich technique
• proximal restoration: composite, bonded amalgam
• these restorations bond to tooth structure, no further preparation for retention. provides tooth reinforcement