Chemomechanical Disinfection Flashcards
(16 cards)
Bacterial interactions in dental biofilm Development
Caries BDS2
Shaping canal
- create a continuously tapering funnel shape
- maintain apical foramen in original position
- keep apical opening as small as possible
What is mechanical preparation?
- creates space to allow irrigating solutions and medicaments to more effectively eliminate micro-organisms from root canal system
Stages in Mechanical Preparation
- bacteria and fungi coronally, less in apical
Apical prep
- size is determined by initial size of root canal apex
- usually a size 25 /ISO size 25
some to 30 to allow irrigation
Ideal properties of irrigant
- 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
Two main ideal properties of irrigants
- killing of biofilm microbes
- detachment of biofilm
Sodium Hypochlorite (NaOCl)
- 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
Why use NaOCl?
- antimicrobial
- dissolves pulp remnants and collagen
- only root canal irrigant dissolves necrotic and vital tissue
- helps disrupt smear layer by acting on organic component
NaOCl concentration
- 3% in Dental hospital; Parcan
Preparation of canal for obturation
- 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
Removal of smear layer
- 17% EDTA
- 10% citric acid
- MTAD (mixture of tetracycline isomer, ana cid and detergent)
- sonic/ ultrasonic mechanism
what is EDTA?
Ethylenediaminetetraacetic acid
- 17%
- chelating agent capable when used with NaOCl
- removing smear layer
- use 1 min
NaOCl complications
- discolouration of fabrics
- opthalmic injuries due to eye contact
- apical extrusion leading to tissue necrosis
- allergic reaction
Chlorhexidine Digluconate
- antibacterial activity
- less antifungal activity than NaOCl
- unable to disrupt biofilms
- biocompatibility
- Parachloroaniline is carcinogenic when chlorohexidine + NaOCl
Proposed Protocol Cleaning and Shaping
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
- 17% EDTA for 1 min
- 3% NaOCl fina rinse
- dry canal using absorbent paper points between irrigants
