Treatment of caries - SHINY MOUNICA.P

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Total no. of slides: 144

No. of illustrations: 48

Total time of presentation :90 min

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REFERENCES

INTRODUCTION

DEFINITION OF DENTAL CARIES

CLASSIFICATION OF TECHNIQUES

HAND PIECE,BURS

SMART PREP BURS,

HAND EXCAVATION

AIR ABRASION

AIR POLISHING

ULTRASONIC INSTRUMENTATION

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SONO ABRASION

CHEMOMECHANICAL CARIES REMOVAL

FACE

LASERS CONCLUSION

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1. STURDEVANT’S Art and science of Operative dentistry 5th edition

2. Minimally invasive dentistry :The management of caries.N.Wilson

3. Current concepts and techniques for caries excavation and adhesion to residual dentinJAdhes Dent 2011;13; 7-22.

4. Dentine caries excavation: a review of current clinical tecniques. British dental journal 2000;188;476-482.

5.Current concepts in cariology DCNA 2010;54(3)

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6.In vitro Evaluation of Five Alternative Methods of Carious Dentine Excavation.Caries Research 2000;34(2)

7.Scanning electron microscopic observations of human dentine after mechanical caries excavation. Journal of Dentistry 2000;28; 179–186.

8.A SEM of different caries removal tecniques on human dentin.Oper Dent 2002;27(4);360-6.

9. Performance of four dentine excavation methods in deciduous teeth. Caries Res 2006;40:117-123.

Efficacy of 4 caries excavtion methods compared .Oper Dent 2006;31;5

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10.In vitro comparison of ceramic burs and conventional tungsten carbide bud burs in dentin caries excavation.Quintessence Int2008;39:495-499.

11.In Vivo Comparison of Reduction in Bacterial Countafter Caries Excavation with 3 Different Techniques .J Dent Child 2011;78:31-5

12.Microhardness as a predictor of sound and carious dentine removal using alumina air abrasion. CariesRes 2006;40:292-295

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13.An in vitro investigation of the effect and retention of bioactive glass air-abrasive on sound and carious dentine.

J Dent 2008;36:214-218.

14.Comparative evaluation of the efficacy of chemomechanical caries removal agent(Papacarie) and conventional method of caries removal: An in vitro study J Indian soc Pedod Prevent Dent 2010 ; 2 ( 28 )73

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15.Selective caries removal with air abrasion. Oper Dent 1998;23:236-243.

16.Efficacy of chemo-mechanical method (carisolv) of caries removal with that of hand cutting and rotary cutting instruments. Annals and essences of dentistry Dec 2011.

17.Effectiveness and Efficiency of Chemomechanical Carious Dentin Removal.Braz Dent J (2006) 17(1): 63-67

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18.Self-limiting caries therapy with proteolytic agents. Am J Dent 2008;21:303-

312.

19.Human teeth with and without dental caries studied by visible luminescent spectroscopy. J Dent Res 1981;60:120-122

20.Diagnodent: An optical method for caries detection. J Dent Res 2004;83:80-83.

21.Residual caries detection using visible fluorescence. Caries Res 2002;36:315-319

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22.Fluorescence-aided caries excavation (FACE) compared toconventional method. Oper Dent 2003;28:341-345.

23.Quantity of remaining bacteria and cavity size after excavation with FACE, caries detector dye and conventional excavation in vitro. OperDent2007;32:236-241

24.Essentials of preventive and community dentistry. 3rd edition Soben Peter.

25.Walsh LJ. The current status of laser applications in dentistry. Austr Dent J 2003;48:146-155

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Dental caries is an infectious microbiologic disease of the teeth that results in localized dissolution and destruction of calcified tissues. -Sturdevant

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Caries removal or rather treatment of the infected dentine, is best defined by outcome criteria, i.e., procedures that lead to local arrestment of the carious process.

GV Black, in 1893—the principle of “extension for prevention”

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Term “caries excavation” was defined as a synonym for “cavity preparation”, which in turn consisted of

“mechanical treatment of the injuries to the teeth produced by dental caries, as would best fit the remaining part of the tooth to receive a filling”

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Stability form

Retention form

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CATEGORY TECHNIQUE

Mechanical, rotary Hand piece , burs

Mechanical, non rotary Hand excavators, air-abrasion ,air polishing, ultrasonics , sono-abrasion

Chemo-mechanical Caridex,carisolv,enzymes

Photo ablation lasers

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Controlled selective rotary excavation Torque controlled motors

Carisolv power drive

Polymer burs

Smart prep burs

Ceramic burs

Fluorescence aided caries excavation

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Conventional Excavation with Burs

Carbon-steel or tungsten-carbide burs

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Enamel pit and fissure caries- No.1 or No.2 round bur.

Carious dentin – round steel excavating burs in a low speed contra-angled hand piece

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A sharp round steel bur- large as lesion

Burs with a positive rake angle -used to cut softer, weaker substances, such as soft carious dentin.

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Microscopic tungsten-carbide particles are held together in a matrix of cobalt or nickel at the head (working end) of the bur.

head- typical spiral-like cutting edges with or without additional cross cuts to improve cutting efficiency.

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Greater number of flutes than carbide bur.

Smoother cutting action

Operator is provided with a better tactile sense.

same caries-removing properties as tungsten-carbide burs

less expensive,

but they are much more prone to corrosion and dulling

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A light force with wiping motion- to discriminate between carious and normal dentin .

start carious dentin excavation from the periphery towards the center of the lesion in order to minimize the risk of infection in case of accidental pulp exposure.

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Tungsten-carbide or carbon-steel burs in low-speed contra-angle handpieces are the most efficient method to excavate carious lesions in terms of time, and are therefore

still the most widely used caries-excavation method.

Performance of four dentine excavation methods in deciduous teeth. Caries Res 2006;40:117-123

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When studied by SEM,this method leaves a homogeneous smear layer with more or less uniform roughness, and dentinal tubules visibly obstructed with smear plugs.

A scanning electron microscopic study of different caries removal techniques on human dentin. Oper Dent

2002;27:360-366.

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Polymer burs:

A “plastic” bur was made of a polyamide/ imide (PAI) polymer, possessing slightly lower mechanical properties than sound dentin.

hard enough to remove decayed dentin,

stops at- hard healthy dentin

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self limiting –

The blade design was developed to remove dentin by locally depressing the carious tissue and pushing it forward along the surface until it ruptures and is carried out of the cavity

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SmartPrep, SSWhite Burs; Lakewood, NJ, USA)

PEKK

Hardness -50 KHN

Higher than carious dentin (0 to 30 KHN)

Lower than sound dentin (70 to 90 KHN)

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available in 3 sizes #2, #4, #6,

smaller than their carbide round bur counterparts

low speed i.e. 500-800 rpm , without water spray.

used with very light air brush type stroke.

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Their cutting edges were not spiralled but straight.

Disadvantage:

To excavate caries from the center to the periphery in order to avoid contact with sound tooth tissue, the bur would

be prematurely and irreversibly damaged

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More residual caries – smart prep burs.

Micro tensile bond strength to carious dentin- excavated with smart prep burs-lower.

TEM

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SmartBurs

In primary teeth, resulted in the highest coincidence between the caries removal endpoint obtained by auto-fluorescence of carious dentin and the actual degree of caries removal.

surface hardness of the SmartBurs (26.6 KHN)

arrested carious dentin (39.2 KHN)

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The CeraBurs are all-ceramic round burs made of alumina-yttria stabilized zirconia.

high cutting efficiency in infected, soft dentin.

replaces both the explorer and the spoon excavator by simultaneously providing tactile sensation, reducing preparation time.

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CeraBurs with different diameters. From left to right: 10-,14-, 18-, and 23-mm diameter.

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In vitro investigation of the caries-removal efficiency and efficacy did not show any significant difference between the ceramic and conventional tungsten-carbide burs.

In vitro comparison of ceramic burs and conventional tungsten carbide bud burs in dentin caries excavation.

Quintessence Int 2008;39:495-499.

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Caries removal with a carbide bur, polymer bur, and spoon excavator produced significant reduction in viable count of both Streptococcus mutans and lactobacilli.

Carbide burs, however, produced greater reduction in the viable count of bacteria followed by polymer bur and spoon excavator.

In Vivo Comparison of Reduction in Bacterial Countafter Caries Excavation with 3 Different Techniques (J Dent Child 2011;78:31-5)

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Mechanical Non-rotary: Hand excavators

Air abrasion

Air polishing

Ultrasonic instrumentation

Sono-abrasion

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Spoon excavator and enamel hatchets –excavation of caries

Sharp excavators are effective and will reduce the force required for caries removal.

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Advantages:

Long term observations have shown adequate tissue removal

Over excavation is unlikely

Accepted procedure especially in pedodonticsand anxious patient

Does not require any expensive equipment

Disadvantages:

High pressure causes pain

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Banerjee, Kidd and Watson in 2000 –

conventional hand excavation appeared to offer the best combination of efficiency and effectiveness for carious dentine excavation.

In vitro Evaluation of Five Alternative Methods of Carious Dentine Excavation Caries Res 2000;34:144–150

.

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Steel bur was the fastest method, followed by the polymer bur, hand excavator and laser.

Steel bur exhibited also the largest overpreparation area, followed by laser, hand excavator and polymer bur.

The largest underpreparation area was found using polymer bur, followed by laser, hand excavator and steel bur.

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Overall, hand excavator seemed to be the most suitable method for carious dentine excavation in deciduous teeth, combining good excavation time with effective caries removal.

Performance of Four Dentine Excavation Methods in Deciduous Teeth Caries Res 2006;40:117-123

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Procedure based on excavating carious cavities in teeth using hand instruments only and subsequent restoration with adhesive filling material (glass-ionomer).

innovative,

largely pain-free,

minimal intervention approach of

treating decayed teeth

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The reasons for using hand instruments :

- it makes restorative care accessible for all population groups,

requires minimal cavity preparation that conserves sound tooth tissues

causes less trauma to the teeth,

- the low cost of hand instruments compared to electrically driven dental equipment,

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the limitation of pain that reduces the need for local anaesthesia to a minimum and reduces psychological trauma

- simplified infection control.

Hand instruments can easily be cleaned and sterilized after every patient

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The reasons for using glass-ionomer are

GIC sticks chemically to both enamel and dentine, the need to cut sound tooth tissue to prepare cavity is reduced,

- fluoride is released

- it is rather similar to hard oral tissues and does not inflame the pulp or gingiva.

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- there is a cavity involving the dentine, and

- that cavity is accessible to hand instruments.

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swelling (abscess) or fistula (opening from abscess to the oral cavity,

- the pulp exposed,

- teeth have been painful for a long time and there may be chronic inflammation of the pulp,

- there is an obvious carious cavity, but the opening is inaccessible to hand instruments

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Mouth mirror

Explorer

A pair of tweezers

Spoon excavators

Enamel hatchet

Carver

Mixing pad and spatula

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1.Place cotton wool rolls alongside the tooth to be treated.

2.Remove plaque from tooth surface with wet cotton wool pellets.

3.Dry the tooth surface with dry cotton wool pellets.

4.If necessary make the entrance of the cavity wider with a dental hatchet.

5.Remove the carious dentin with excavators starting at the enamel dentin junction.

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6.Fracture off unsupported thin enamel with the hatchet. Make sure the enamel does not contain any carious spots.

7.Clean the cavity with wet and dry cotton wool pellets.

8.Remove the caries near the pulp carefully.

9.Clean the cavity again with cotton wool pellets.

10.Check the relation of the tooth to be restored with the opposing teeth by asking the patient to bite.

11.Complete the procedure by drying the cavity with dry cotton pellets.

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Dr. Robert B. Black was the first to study air-abrasives technology in dentistry in 1943.

In 1951, S.S.White introduced the first air-abrasive system – Airdent

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The principle employed by the airdent unit utilizes kinetic energy or inertia as a rapid and not unpleasant means of removing tooth structure by incorporating a fine abrasive material in a high velocity gaseous propellent.

EK= ½ m v2

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Air abrasion is not a completely painless method of cavity preparation;

It eliminates

vibration,

bone-conducted noise,

pressure and heat.

The traumatic influence on tooth structure and periodontal tissue is reduced to a minimum.

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Unit

Foot control

Hand piece- consists of a handle, a shaft – an adjustable contra-angle (ball and socket) and

a tip or nozzle in a 90 relationship to the shaft.

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Basic principles of air-abrasive:

Air abrasive depends for its action on a fine stream of suitable gas carrying a controlled quantity of small abrasive particles

Abrasive Materials:

Al2O3 – For cutting tooth substance

CaMgCO3 – Dolomite – oral prophylaxis

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US FDA approval for clinical use of 27.5 alumina particles

It possess a hardness of 9 on Moh’s scale and its particles possess sharp edges and pointed corners when properly prepared.

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Propellants: CO2 was found to possess certain advantage

for this purpose. Practically free from moisture Non-toxic in low concentrations Convenient and almost universally available

The pressure of the liquid CO2 varies from 700 to 1300 pounds per square inch.

This pressure is reduced to app.115 pounds in the line and

80 to 45 pounds at the nozzle.

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A nozzle tip distance of 1mm- the angulationis zero

At 2 mm total angulation - 7.

At 5mm it is 13.

At 10 mm it is 23

and at 15mm it is 35.

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Action of air abrasive is influenced by factors

propellant pressure

type and particle size of the abrasive used,

abrasive mixture

nozzle bore and length,

nozzle distance from the enamel surface

nozzle angulation.

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No.561chrome plated dental bur =6 mg of enamel _ 30 sec at 1725 rpm , pressure of 2 pounds.

Al2O3 _ 80 psi—a nozzle of 0.018 inch inside diameter and nozzle tip distance of 7

to 13 mm -90,

air abrasive is capable of removing 30 mg of enamel in 30 seconds.

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Hand piece Control:

The operator must develop close co-ordination between the eye, hand and foot.

no tactile relation between the instrument and tooth being operated on,

visual sense.

Thus, good eye sight and good lighting are imperative for this technique.

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Hand piece grasp:

Air abrasive hand piece is held lightly in the pen grasp .

No pushing or pulling is necessary .

3rd or 4th finger is generally used not as a brace but as a rest for steadying the instrument.

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Nozzle angulation must be correlated with nozzle tip distance.

Greater the nozzle tip distance the greater will be the angulation

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Straight line cut:

high degree of definition is desired.

This type of cut utilizes close nozzle distances and is precise and narrow.

Angle cut:

greater nozzle distance, together with the required nozzle angulation.

As the nozzle distance from the substance being cut increases, the angle of the walls increases proportionately.

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Advantages of angle cut–

greater cutting speed and

less visual interference

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Limitations of air abrasive system— abrasive particles cause inhalational

problems.

no tactile guidance

difficult to remove the existing restoration

High cost

When the abrasive particles strikes the surface of the mirror, it becomes frosted.

Might damage the cavosurface sound tooth enamel.

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The major drawback of air-abrasion excavation of carious dentin is that sound dentin is more efficiently removed than carious dentin.

Microhardness as a predictor of sound and carious dentine

removal using alumina air abrasion. CariesRes 2006;40:292-295.

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High Speed Drills Air Abrasion

Rotary bur cause micro

fractures

No micro fractures

Excessive destruction of

tooth structure

Less destruction of tooth

structure

Heat, vibration,bone

conducted noise-patient

discomfort

Heatless, vibration less,

minimal sound

Patient Anxiety Patient friendly

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Spherical glass beads

Polycarbonate resin-crushed powder removed artificially softened dentin more selectively without cutting sound dentin or enamel.

Selective caries removal with air abrasion. Oper Dent 1998;23:236-243.

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A mixture of alumina and hydroxyapatite

in a volume ratio of 3:1, with particle sizes ranging from 3 to 60 μm, was shown to be as efficient as conventional hand excavation with dental spoons.

Banerjee A, Kidd EA, Watson TF. In vitro evaluation of five alternative methods of carious dentine excavation. Caries Res

2000;34:144-150.

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Bioactive glass powder (Bioglass, NovaminTechnology;Alachua, USA) with a particle diameter between 25 and 32μm was also explored.

Risk of unnecessary sound dentin removal was reduced because of the difference in cutting rate between sound and carious dentin.

An in vitro investigation of the effect and retention of bioactive glass air-abrasive on sound and carious dentine.

J Dent 2008;36:214-218.

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Water soluble sodium bicarbonate and tricalcium phosphate

0.08% by weight

to improve the flow characteristics

air pressure,

concentric water jet.

As the abrasive is water soluble it does not escape too far from the operating field.

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Razoog and Koka in 1994,

increasing the air-pressure beyond 90 psi actually reduced the abrasiveness of the microprophy system.

This was due to a phenomenon -choked flow.

as the air pressure exceeds the critical pressure, the mass flow of particles will reduce thus limiting the system’s abrasiveness.

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Commercially recommended use of this technique is to

remove surface enamel stains,

plaque and calculus

overzealous use - remove healthy tooth structure

removal of carious dentine at the end of cavity preparation.

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Nielson et al. in 1950s

Magnetostrictive instrument with a 25 kHz oscillating frequency.

Thick aluminium oxide and water slurry, created by the cutting action.

Mechanism of actionKinetic energy of water molecules being transferred to the tooth surface via the abrasive through the high speed oscillations of the cutting tip.

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Nielson attempted to analyse the results from altering

the pressure applied,

the length of use of the instrument,

the powder water ratio in the slurry,

the nature of the material

cut and the type of abrasive used.

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SONIC OSCILLATION (SONOABRASION)

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Removal of carious dentin using high frequency ,sonic air scaler with modified abrasive tips

First Design

•Sonic micro unit designed by Dr.Hugo Unterbrink and

Mosele

•Based on Soniflex 2000L and 2000N Air scaler Hand

piece

•Oscillations - < 6.5 KHZ

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Tips- elliptical motion - transverse distance of between 0.08 to 0.15 mm

longitudinal movement of between 0.55 –0.135mm

tips are diamond coated on one side using

40 grit diamond

Cooled using water irrigant at a flow rate of between 20-30 ml/min.

The operational air pressure -3.5 bar.

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A lengthways

halved torpedo

shape

9.5mm

long,1.3mm wide

A small hemisphere

1.5 mm diameter

A large

hemisphere 2.2mm

diameter

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Torque Applied – 2N More pressure - dampens oscillations –

cutting efficiency reduced.

Indications

•Carious dentin removal

•Finishing cavity preparations

More studies needed to prove its efficiency

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Advantage

less over preparation than with rotary instruments

smaller access cavity is possible.

Disadvantage

unclear completeness of excavation

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CHEMO MECHANICALCARIES REMOVAL (CMCR)

Chemical softening of carious dentin followed

by its removal by gentle excavation

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Dentin

Inorganic – 70% Organic matrix - 20 % H2O – 10 %

18 % Collagen 2 % Non Collagen

Proline + Glycine - Polypeptides – Tropocollagen - Fibril

• Chlorination of Partially Degraded Collagen (Conversion of Hydroxyproline to Pyrrole-2-carboxylic acid)

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CMCR limits the removal of sound tooth structure, the cutting of open dentinal tubules, pulpal irritation pain

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Goldman and Kronman

Na0Cl + Sorenson’s Buffer

(Glycine ,NaOH,NaCl)

N Mono Chloro Glycine

(GK 1019)

Glycine replaced by

Amino Butyric

acid

N-Mono Chloro DL2 amino

butyric acid

(NMAB) –GK 101E

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Chlorination of Partially Degraded Collagen (Conversion of Hydroxyproline to Pyrrole-2-carboxylic acid)

Cleavage by Oxidation of glycine residues –Disruption of collagen – more friable collagen- removed.

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Solution 1: 1% NaOCl

Solution 2: glycine+amino butyric acid+

NaCl+NaOH

pH = 11

Delivery system- reservoir,

heater and pump,

handpiece,

applicator tips

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Advantages: avoids painful procedure

reduced need for L.A.

conservation of tooth structure

dental phobics

deciduous teeth

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Rotary & hand instruments were still needed

Large volumes of solution

Slow

Long term studies were lacking

Short shelf life

Special delivery system was needed

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carisolv107

2 Syringes

NaOCl

Pink Viscous gel ( Lysine,

Leucine, Glutamic Acid

+Carboxymethyl cellulose +

Erythrosine )

Max Volume of Gel – 0.2 – 1 ml

Cloudy - frosty

‘A silent revolution’

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Multi mix

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singlemix110

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operative steps in chemomechanical caries excavation include:

(1) application of the solution, (2) scrapping off the carious dentin with

possible change of instrument size,(3)rinsing, and (4) repetition of the procedures until all caries

is removed.Time required 10-15 minVolume required 0.2 -1 ml

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Carisolv power drive is a faster and easier way of working with carisolv.

Advantages:-

It has unique torque limitations and this helps to protect the healthy dentine.

It works at very low speed, thereby minimizing noise and pain.

Power drive is used with special star bur – 1.0, 1.5, 2.0. These burs work with power drive or a low speed handpiece of maximum 300 rpm.

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CARIDEX CARISOLV

SOL I 1% NaOCl 0.5 % NaOCl

SOL II 0.1MAminobutyric acid

glyciene

0.1M NaCl,0.1 M NaOH

0.1M glutamic acid / leucine /

lysine, NaCl, NaOH

Dye - Erythrocyin

pH 11 11

Physical Nature Liquid gel

Volume 100-500ml 0.2 – 1ml

Time required 10-15 mins 10-15 mins

Instruments Applicator tips Specially designed

Active time 1 Hr 20 mins118

Painless

No need of local anesthesia

Conservation of sound tooth structure

Reduced risk of pulp exposure

Well suited for anxious

Better than Caridex

LIMITATION

•Rotary and hand instruments may still be needed

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Complete removal of caries was achieved significantly in both the methods,( Papacarie, with conventional slow-speed rotary instrument(bur)

there was less marked destruction of dentinal tubules in chemomechanical caries removal method by Papacarie.

Comparative evaluation of the efficacy ofchemomechanicalcaries removal agent(Papacarie) and conventional method of caries removal: An in vitro study J INDIAN SOC PEDOD PREVENT DENT

2010( 28 )|

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Removal of carious dentin with Carisolv is highly effective than that of Hand Excavation, but slightly less than round carbide bur.

It may be because of carisolv which removes only the infected dentin and not the affected dentin.

Efficacy of chemo-mechanical method (carisolv) of caries removal with that of hand cutting and rotary cutting instruments. Annals and essences of dentistry Dec 2011

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Chemomechanical excavation using Carisolvgel was the slowest technique.

hand excavation presented higher efficiency and effectiveness than chemomechanicalexcavation.

Effectiveness and Efficiency of Chemomechanical Carious Dentin Removal. Braz Dent J (2006) 17(1): 63-67

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Pepsin in a phosphoric acid/sodium biphosphate buffer- alternative to CMCR.

phosphoric acid dissolves the inorganic component of carious dentin.

pepsin - organic part of the carious biomass

denatured collagen

Self-limiting caries therapy with proteolytic agents. Am J Dent 2008;21:303-312

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Advantage:

more specific by digesting only denatured collagen (after the triple-helix integrity is lost) than the sodium hypochlorite-based agents.

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In 1989 Goldsberg and Keil

Achromobacter collagenase- did not affect the sound layers of dentin beneath the lesion.

In 1996 Norbo, Brown and Jan -Enzyme

Pronase –non specific proteolytic enzyme –

Streptomyces griseus

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This technique was developed as a direct method to clinically differentiate between infected and affected carious dentin.

Changes in tooth fluorescence detects early tooth surface caries.

Lennon et al. in 2002 studied the residual caries detection using visible fluorescence.

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Based on the fact that several oral microorganisms produce orange-red fluorophores as by-products of their metabolism (porphyrins), infected carious tissue will fluoresce especially in the red fraction of the visible spectrum due to the presence of proto- and meso-porphyrins.

Human teeth with and without dental caries studied by visible

luminescent spectroscopy. J Dent Res 1981;60:120-122

Diagnodent: An optical method for caries detection.

J Dent Res 2004;83:80-83.129

Carious dental tissue fluorescences more intensely in the red portion of the visible spectrum (>540 nm) than the sound dentine.

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Violet light (370-420 nm) –

The operator can observe the cavity through a 530 nm – high pass filter.

Areas exhibiting orange-red fluorescence –caries -- removed by appropriate size bur.

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Compared to Caries Detector or the visual-tactile method for establishing the caries removal endpoint, the FACE method showed the highest sensitivity, specificity, percentage correct score, and predictive values for residual caries detection, as evaluated using confocal microscopy.

Residual caries detection using visible fluorescence. Caries Res 2002;36:315-319

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There was a significant reduction in the number of samples presenting residual bacteria after excavation with FACE, when compared to Carisolvor bur excavation guided by Caries Detector(1)

Histological examination after staining with ethidium bromide revealed fewer samples presenting bacteria in dentin when the FACE method was used than was the case with conventional bur excavation(2)

1.Efficiency of 4caries excavation methods compared. Oper Dent 2006;31:551-555.

2.Fluorescence-aided caries excavation (FACE) compared toconventional method. Oper Dent 2003;28:341-345.

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Advantages: very efficient, with less time needed to

excavate caries and without a need to change instruments, apply chemical agents, or to test the cavity with an explorer.

FACE was apparently not associated with an increased cavity size or overexcavation.

Efficiency of 4 caries excavation methods compared. Oper

Dent 2006;31:551-555

Quantity of remaining bacteria and cavity size after excavation with FACE, caries detector dye and conventional excavation in vitro.

OperDent2007;32:236-241.

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LASER THERAPY

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Light Amplification by Stimulated Emission of Radiation

In 1960, Theodore Maiman developed the first working laser device which emitted a deep red-coloured beam from a ruby crystal applied to cutting both hard and soft tissues in the mouth

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Efficacy of laser depends on •Pulse energy

•Optical properties of incident tissue

•Wavelength characteristics

Applications•Selective Hard Ablation•Selective Carious Dentin Removal•Destroy S.Mutans•Sealing of Fissures•Adjunctive treatment in caries prophylaxis•Modify structures of dentin and enamel tissue

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Ablation:The absorption differences between

carious and healthy dentin were the highest at blue spectral range

0.4J/cm2 but below 1.8J/cm2.

The laser energy must be delivered uniformly to the lesion surface.

Murray et al. –remaining dentine thickness should be at least

0.5 mm to avoid pulp injury.

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CO2 lasers and Nd :YAG produce surface changes in enamel such as roughness, cracking, fissuring, melting and recrystallisation.

generate markedly elevated surface and pulpal temperature.

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ArF excimer lasers have been reported to remove dental caries.

Krypton F excimer laser has been shown to cut dentin;

however enamel is resistant to effective ablation.

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Walsh LJ. The current status of laser applications in dentistry. Austr Dent J 2003;48:146-155

CO2 laser irradiation inhibits the progression of caries like lesion up to 85%.

Er : YAG -40%

Er, Cr : YSGG - 60% caries reduction

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Er : YAG lasers, Er : YSGG and Er, Cr : YSGG lasers operate at wavelengths of 2940, 2790 and 2780 nm.

These wavelengths correspond to the peak absorption range of water in the infra red spectrum.

The efficiency of ablation is greatest for the Er : YAG laser.

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Er-based laser systems - popping sound.

MECHANISM OF ACTION

A laser powered hydrokinetic system delivers photons into an air-water spray matrix with resultant microexplosive forces on water droplets.

The mechanism of hard tissue cutting is based on this process.

This system with its accompanying air water spray has been shown to cut enamel, dentine, cementum and bone efficiently and clearly without any deleterious thermal effects on dental pulp.

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