New Advances in Caries Removal

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					New Advances in
Caries Removal

  Dr Wael Al-Omari
 BDS, MDentSci, PhD
     Caries Removal

Drawbacks of Conventional Methods:
   Contamination and cross-infection
   The need for presterilisation cleaning.
      1-Manual cleaning of burs
      2-Washer disinfection.
      3-Ulrasonic cleaners with enzymatic detergents
   Removal of infected and unaffected tissues.
    - Is total caries removal necessary?
   Noise, vibration and discomfort experienced with
    burs.
    Rational behind New Developments
   Removal of only infected dentin
   Reduce patients anxiety
   Provide favorable surface features for bonding
   Reduce contamination and cross-infection
   Reduce the need for anesthesia
   Easier recognition between infected and
    uninfected dentin
   Provide equal or superior efficiency compared
    to conventional methods
   Reduce cost.
    New Developments in Caries Removal

   Lasers
   Air Abrasion (Kinetic Cavity Preparation)
   Polymer Burs
   Micropreparation Burs.
   Photoactivated Disinfection
   Carisolv Gel
   Atraumatic Restorative Treatment.
   Caries-Detector Dyes
                    Lasers
   Early Lasers (Caron dioxide, ruby and
    Nd:YAG):
     1- Inefficient cutting
     2- Excessive heat generation
     3- More efficient for soft tissue surgery.
Nd:YAG laser ablated dentin showing
craters and cracks and heat induced
       band (Lin et al, 2001)
Erbium Lasers

   Erbium yttrium aluminum garnet
    (Er:YAG, 2.94 µm wavelength)

   Erbium chromium yttrium scandium
    gallium garnet (Er,Ch:YSGG, 2.78
    µm wavelength)
      Mechanism of ablation by erbium lasers

   Thermomechanical Ablation
    - High absorption coefficient in water and high
       affinity for hydroxyapatite.
     - Absorbed heat cause microexplosions and
       microfragmentataion of target issue.
     - Irradiated surface demonstrate
       microirregularities, absence of smear layer,
       open tubules, absence of extensive thermal
       effects.
Cavity prepared with erbium laser
Bur cut versus Er,ch:YSGG laser cut dentin
         (Ekworapoj et al, 2007)
    Advantages of erbium lasers
   No thermal effect on target tissues and
    pulp.
   Noiseless, no vibrations.
   No harmful effect on the pulp.
   Distinguishing between infected and
    uninfected dentine might be possible.
   Various clinical applications:
    periodontics, endodontics, operative
    dentistry.
Disadvantages of erbium lasers
     Cost
     Erbium laser preparations must be
      followed by acid etching for reliable
      bonding to resin composite
     May weaken the irradiated surface
    (lower microhardness)
     Defocusing effect due to water spray
     Tissues can be only removed when it is
      visible to operator’s line of sight.
     Lack of tactile sensation
     Large devices
Waterlase MD   Biolase ezlase 940
Future Development

   New more efficient generations of
    erbium lasers.
   Lasers with femtosecond pulse
    duration (pulse duration = 10-15 s)
               Air Abrasion
       (Kinetic Cavity Preparation)

   This technique uses a pressurized
    stream of small aluminum oxide
    particles to abrade carious lesion.
   Typical Air Abrasion system:
    - Particle diameter 27-50 µm.
    - Powder flow rate 0.7-4.2 g/min
    - Air pressure 40-160 psi
    - Operating distance from tooth 0.5-2 mm
Air abrasion
 Handpiece




               Air Abrasion Unit
    Clinical Indications
   Removal of superficial enamel defects
   For detection pit and fissure caries by removal of
    organic debris.
   Removal of enamel surface stains.
   Removal of localized minimal carious lesion
   Surface preparation of abfractions and abrasions
    to brake the glaze of the surface for better
    bonding.
   Removal of existing restorations.
   The need for anesthesia may be avoided
    because of the cooling effect of the high
    pressure air
Cavity prepared using air abrasion technique
Advantages of Air Abrasion

   Less painful than bur preparation
    due to less noise and vibration.
   More conservative than bur for
    minimal fissure and pit caries.
   Roughened surfaces may favor
    better bonding….However air
    abrasion is not a substitute for acid
    etching
Limitations of Air Abrasion
   There is little tactile sensation
   Unable to remove gross caries.
   Removes normal and relatively hard dentin.
   Remove exposed cementum and root
    dentin.
   Splattering f powder-risk of ingestion.
   Unable to prepare well-defined cavity
    margins.
   Does not obviate the need for acid etching.
   May lacerate soft tissues
   Removal of large amalgam causes release
    of mercury
   Mandatory need for rubber dam, high
    velocity evacuation and protective eyewear
Future Developments in Air Abrasion

   Less abrasive powders
     - Softer particles may be more
       effective in selective removal of
       carious dentine
             Polymer Bur
   Described by Boston (2000).
   Made of a softer polyamide/imide polymer
    material.
   Remove infected dentine only
   Manufacturer: SmartPrep (SS White, USA)
   Harder than carious dentine and softer than
    healthy dentine
   Designed for single use on slow-handpiece
   Remove caries from central of lesion to
    periphery
   Less effective than carbide bur in caries
    removal (Dammaschke et al, 2006)
Polymer burs   SmartPrep before (1a) and after
               (1b) use (Dammaschke et al, 2006)
Micropreparation Burs
   Fissurotomy Burs (SS White,USA) allow
    exploration of the fissures with minimal
    removal of enamel.
   It is 1.5-2.5 mm in length and tapers to
    fine carbide tip.
    Other burs such as Brassler 889M-007 bur
    and Microdiamond 838M-007 burs are
    used for minimal preparation.
   Microinstruments (Micropreparation set)
    requires low contact pressure (< 2N)
Fissurotomy Bur
Conventional bur   versus   fissurotomy bur
     Photoactivated Disinfection
   The system use disinfectant solution
    applied to deep caries, allowed to
    penetrate softened dentin for 60 s, and
    then photoactivated with low-powered
    diode laser for 1 min.
   Dilute toluidine blue binds to bacteria.
    Red light activation release oxygen that
    kills the cells
   Healthy tissues are not damaged by
    the laser
   Toluidine blue is safe at the used
    dilution
   Toludine blue and laser acts together
    effectively.
Photo-Activated Disinfection (PAD)
            Carisolv Gel
   Carisolv s a chemomechanical method
    for caries removal.
   It is a mixture of amino acids and 05%
    sodium bicarbonate
   The resultant high-pH chloramines
    reacts with denatured collagen in
    carious dentin
   Softened dentin is removed with
    special hand instruments
Special hand instruments used with Carisolv Gel
Clinical Indications For Carisolv Gel

   Removal of root and coronal caries
    where access is easily obtained
   Due to selective removal of carious
    dentine, the need foe anesthesia is
    reduced , thus the technique is
    indicated in children, dental-phobic
    patients and special needs patients
     Advantages of Carisolve Gel
   Selective removal of carious dentine.
   The reduced need for anesthesia
   Does not affect the bonding to
    composite.
   Removes smear layer
   Does not cause adverse effect on the
    pulp.
Disadvantages of Carisolv Gel

   Technique requires longer time than
    conventional method.
   May be inefficient for removing
    caries at enamel-dentin junction.
   Caries under overhanging enamel
    may go unnoticed.
   Large lesions needs to be accessed
    using rotary bur.
Atraumatic Restorative Treatment ِ
(ART

   Atraumatic Restorative Treatment is
    a procedure based on removing
    carious tooth tissue sing hand
    instruments alone and restoring the
    cavity with an adhesive restorative
    material namely glass ionomer
Hand instruments used in ART
Reasons for using hand instruments in ART

    Makes restorative procedure
     accessible to all population.
    Minimal cavity preparation
    Low cost
    Reduce need for anesthesia
    Simplified infection control due to
     easy cleaning and sterilization
Reason for using glass-ionomer in ART

   Glass ionomer sticks chemically to
    enamel and dentin
   Fluoride release
   Compatible to oral and hard dental
    tissues
Advantages of ART
   Benefit the less-industrialized and
    deprived communities
   Minimal invasion preparations
   Friendly procedure for children,
    fearful adults, physically or mentally
    handicapped, people living in
    nursing homes and the home-bound
    elderly
Disadvantages of ART

   Restorations tend to fail and wear.
   Incomplete removal of bacteria
   Wear and failure means that
    patients require frequent review by
    trained personnel
   Difficult o remove caries in
    inaccessible lesions.
        Caries Detection Dyes
   Dyes such as 1.0% acid red in propylene
    glycol.
   They stain infected dentine and organic
    matrix of demineralised of carious dentin
    that should not be removed.
   They stain dentin naturally with low minerals
    such as circumpulpal dentin and enamel-
    dentin junction
   Result in overpreparations.
   Not useful in detecting pt and fissure caries
    because they stain food debris and other
    organic materials in the fissure
   They are not recommended
Caries detecting dyes stains demineralised
matrix of carious dentin that should not be
removed

				
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posted:9/22/2011
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