New Advances in Caries Removal Dr Wael Al-Omari BDS

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New Advances in Caries Removal

• Dr Wael Al-Omari
• BDS, MDentSci, PhD

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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.

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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.

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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

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Lasers

• Early Lasers (Caron dioxide, ruby and NdYAG)
• 1- Inefficient cutting
• 2- Excessive heat generation
• 3- More efficient for soft tissue surgery.

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NdYAG laser ablated dentin showing craters and
cracks and heat induced band (Lin et al, 2001)
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Erbium Lasers

• Erbium yttrium aluminum garnet (ErYAG, 2.94 µm
  wavelength)
• Erbium chromium yttrium scandium gallium garnet
  (Er,ChYSGG, 2.78 µm wavelength)

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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.

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Cavity prepared with erbium laser
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Bur cut versus Er,chYSGG laser cut dentin
(Ekworapoj et al, 2007)
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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.

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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
  operators line of sight.
• Lack of tactile sensation
• Large devices

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Biolase ezlase 940
Waterlase MD
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Future Development

• New more efficient generations of erbium lasers.
• Lasers with femtosecond pulse duration (pulse
  duration 10-15 s)

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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

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Air abrasion Handpiece
Air Abrasion Unit
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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

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Cavity prepared using air abrasion technique
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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

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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

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Future Developments in Air Abrasion

• Less abrasive powders
• - Softer particles may be more
• effective in selective removal of
• carious dentine

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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)

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Polymer burs
SmartPrep before (1a) and after (1b) use
(Dammaschke et al, 2006)
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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 (lt 2N)

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Fissurotomy Bur
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Conventional bur versus
fissurotomy bur
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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

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• Healthy tissues are not damaged by the laser
• Toluidine blue is safe at the used dilution
• Toludine blue and laser acts together
  effectively.

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Photo-Activated Disinfection (PAD)
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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

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Special hand instruments used with Carisolv Gel
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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

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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.

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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.

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?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

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Hand instruments used in ART
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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

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Reason for using glass-ionomer in ART

• Glass ionomer sticks chemically to enamel and
  dentin
• Fluoride release
• Compatible to oral and hard dental tissues

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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

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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.

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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

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Caries detecting dyes stains demineralised matrix
of carious dentin that should not be removed
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