Chemomechanical Disinfection Flashcards

1
Q

Bacterial interactions in dental biofilm Development

A

Caries BDS2

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2
Q

Shaping canal

A
  1. create a continuously tapering funnel shape
  2. maintain apical foramen in original position
  3. keep apical opening as small as possible
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3
Q

What is mechanical preparation?

A
  • creates space to allow irrigating solutions and medicaments to more effectively eliminate micro-organisms from root canal system
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4
Q

Stages in Mechanical Preparation

A
  • bacteria and fungi coronally, less in apical
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5
Q

Apical prep

A
  • size is determined by initial size of root canal apex
  • usually a size 25 /ISO size 25
    some to 30 to allow irrigation
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6
Q

Ideal properties of irrigant

A
  • low cost
  • washing action
  • reduction of friction
  • temp control
  • improving cutting of dentine by instruments
  • dissolution of organic and inorganic matter
  • good penetration within root canal system
  • detachment of biofilm
  • non-allergenic
  • does not weaken dentine
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7
Q

Two main ideal properties of irrigants

A
  • killing of biofilm microbes
  • detachment of biofilm
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8
Q

Sodium Hypochlorite (NaOCl)

A
  • NaOCl ionises in water into Na+ and hypochlorite ion OCl-
  • establish equilibrium with hypochlorous acid (HOCl)
  • acid/ neutral HOCl predominates
  • pH 9 and above OCl- predominates
  • HOCl is responsible for antibacterial activity
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9
Q

Why use NaOCl?

A
  • antimicrobial
  • dissolves pulp remnants and collagen
  • only root canal irrigant dissolves necrotic and vital tissue
  • helps disrupt smear layer by acting on organic component
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10
Q

NaOCl concentration

A
  • 3% in Dental hospital; Parcan
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11
Q

Preparation of canal for obturation

A
  • smear layer formed during prep
  • organic pulpal material and inorganic dentinal debris
  • superficial 1-5 microm with packing into tubules
  • bacterial contamination, substrate and interferes with disinfection
  • prevents sealer penetration
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12
Q

Removal of smear layer

A
  • 17% EDTA
  • 10% citric acid
  • MTAD (mixture of tetracycline isomer, ana cid and detergent)
  • sonic/ ultrasonic mechanism
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13
Q

what is EDTA?

A

Ethylenediaminetetraacetic acid
- 17%
- chelating agent capable when used with NaOCl
- removing smear layer
- use 1 min

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14
Q

NaOCl complications

A
  • discolouration of fabrics
  • opthalmic injuries due to eye contact
  • apical extrusion leading to tissue necrosis
  • allergic reaction
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15
Q

Chlorhexidine Digluconate

A
  • antibacterial activity
  • less antifungal activity than NaOCl
  • unable to disrupt biofilms
  • biocompatibility
  • Parachloroaniline is carcinogenic when chlorohexidine + NaOCl
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16
Q

Proposed Protocol Cleaning and Shaping

A

once canal prep is done, canal should be finally irrigated with
1. 3% NaOCl Parcan thoughout instrumentation and at least 30ml after instrumentation complete with MDI - manual dynamic irrigation
- at least 10 mins prior to obturation

  1. 17% EDTA for 1 min
  2. 3% NaOCl fina rinse
  • dry canal using absorbent paper points between irrigants