Minimally Invasive Restorative Dentistry

Introduction• It is generally accepted by dental

practitioners that prevention is the most

conservative, least costly method of

maintaining their patients’ teeth over the long

term.

• Prevention has been the cornerstone of

modern dentistry

Factors Influencing Conservative Approach

• Operator• Tools:

DiagnosticOperating

• Restorative materials• Oral environment condition• Socioeconomic condition of the patient

Operator

Understanding the caries disease nature

Caries irreversible defects

Caries irreversible defects Demineralization followed

by organic degradation

Caries reversible disease Demineralization followed

by remineralization

Understanding the caries disease nature

Caries reversible defects

Elimination microorganism to suppress demineralization

Saturation the saliva with fluoride, calcium, and phosphate To increase remineralization

Understanding the caries disease nature

[I] Caries Prevention

[1] Fluoride ExposureFluoride in trace amounts increases the resistance of

tooth structure to demineralization and is therefore a

particularly important consideration for caries prevention.

When fluoride is available during cycles of tooth

demineralization, it is a major factor in reduced caries

activity

The availability of fluoride to reduce caries risk is

primarily achieved by fluoridated community

water systems, but also may occur from fluoride

in the:

Diet

Toothpastes

Mouthrinses

Professional topical applications.

The optimal fluoride level for public water supplies is about 1 part per million (ppm).

Public water fluoridation has been one of the most successful public health measures.

At 0.1 ppm and below, the preventive effect is lost and the caries rate is higher for such populations lacking sufficient fluoride exposure.

Excessive fluoride exposure (10 ppm or

more) results in fluorosis, a brownish

discoloration of enamel, termed mottled

enamel.

Mottled Enamel.

Fluorides exert their anticaries effect by three different mechanisms;

First:

The presence of fluoride ion greatly

enhances the precipitation into tooth

structure of fluorapatite from calcium

and phosphate ions present in saliva.

This insoluble precipitate replaces the

soluble salts containing manganese and

carbonate that were lost because of

bacterial-mediated demineralization.

This exchange process results in the

enamel becoming more acid-resistant.

Second

Incipient, noncavitated, carious lesions are

remineralized by the same process.

Third

Fluoride has antimicrobial activity.

In low concentrationsFluoride ion inhibits the enzymatic production

of glucosyltransferase.

In high concentrations (12,000 ppm)Used in topical fluoride treatments, fluoride

ion is directly toxic to some oral

microorganisms, including MS.

[2] Immunization IgA antibodies are capable of agglutination

(clumping) of oral bacteria.

This prevents adherence to the teeth and

other oral structures, and they are more

easily cleared from the mouth by swallowing.

For patients with high concentrations of

MS, agglutinating IgA may have an

important anticaries effect.

However, it is known that the procedure is

more effective against smooth surface

lesions than pit-and-fissure lesions.

[3] Salivary FunctioningSaliva is very important in the

prevention of caries.

While xerostomia may occur because

of aging, it is more commonly a result

of a medical condition or medication.

Lack of saliva greatly increases the

incidence of caries.

Saliva stimulants (gums, paraffin waxes,

or saliva substitutes) also may be

prescribed for patients with impaired

salivary functioning.

[4] Antimicrobial AgentsA variety of antimicrobial agents also are

available to help prevent caries.

In rare cases, antibiotics might be considered,

but the systemic effects must be considered.

As already presented, fluoride has antimicrobial

effects.

Chlorhexidine

Is showing excellent results. It was prescribed as a 0.12%

rinse for high-risk patients for short-term use.

It may used in as varnish and the most effective mode of

varnish use is as a professionally applied material .

Chlorhexidine varnish enhances remineralization and

decreases MS presence.

[5] DietDietary sucrose has two important detrimental

effects on plaque.

First, frequent ingestion of foods containing

sucrose provides a stronger potential for

colonization by MS, enhancing the caries

potential of the plaque.

Second, mature plaque exposed frequently

to sucrose rapidly metabolizes it into organic

acids, resulting in a profound and prolonged

drop in plaque pH.

Caries activity is most strongly stimulated by

the frequency, rather than the quantity, of

sucrose ingested.

[6] Oral HygienePlaque free tooth surfaces do not decay!

Daily removal of plaque by dental flossing,

tooth brushing, and rinsing is the single

best measure for preventing both caries and

periodontal disease

[7] Xylitol GumsXylitol is a natural five-carbon sugar

obtained from birch trees.

It keeps the sucrose molecule from

binding with MS.

Furthermore, MS cannot ferment (metabolize) xylitol.

Thus xylitol reduces MS by:

1) Altering their metabolic pathways

2) Enhances remineralization

3) Arrest dentinal caries.

It is usually recommended that a patient chew a

piece of xylitol gum after eating or snacking for

5 to 30 minutes.

Chewing any sugar-free gum after meals

reduces the acidogenicity of plaque because

chewing →→→ stimulates salivary flow,

which improves the buffering of the pH drop

that occurs after eating.

[8] Pit-And-Fissure SealantsAlthough fluoride treatments are most effective in

preventing smooth surface caries, they are less

effective in preventing pit-and-fissure caries.

In Sealants have three important preventive

effects;

First, sealants mechanically fill pits and fissures with

an acid-resistant resin.

Second, because the pits and fissures are

filled, sealants deny MS and other cariogenic

organisms their preferred habitat.

Third, sealants render the pits and fissures

easier to clean by tooth brushing and

mastication.

Diagnostic Tools

Loops and Microscope• Highly magnificatation, and

precise diagnostic tools (Loops, and microscope)

• Micro dentistry replaces macrodentisrty

– Microscopic removal of

diseased tissues

– Preservation of healthy

tissues and structural

integrity of the tooth

Digital Radiograph• Lower exposure of radiation

• It diagnose proximal caries

adequately

• Poor diagnosis for the oclusal

surface caries

• Image enhancement,

magnification, density

assessment and color coding if

required

Digital Radiograph

Classification for proximal caries– 0 = radiographiclly sound surface– 1 = lesion in the outer half of enamel

– 2 = lesion in the inner half of enamel– 3 = lesion in the outer half of dentin– 4 = lesion in the inner half of dentin

Diagnosis sophisticated, and treatment is by remineralization

Diagnosis easy, and treatment is by caries removal

Digital Radiograph

[II] New Methods in Caries Detection

[1] DIAGNOdent Laser Caries Detection Aid

DIAGNOdent uses a pulsed red light (655nm

wavelength) to illuminate the tooth and analyses the

emitted fluorescence from bacterial products, which

changes with tooth demineralization.

The demineralization is given a numerical value that

relates to the fluorescence intensity.

This technique can be used for the accurate

diagnosis of:

Primary occlusal caries

Caries on flat, accessible surfaces

But it does not detect:

Interproximal

Subgingival Caries

(a) The DIAGNOdent probe emits a red light, which is shine onto the tooth.(b) DIAGNOdent: The emitted fluorescence from the tooth surface changes with tooth demineralization

DIAGNOdent Laser Caries Detection Aid

The DIAGNOdent pen is a hand-held laser caries detection aid.  DIAGNOdent aids in the detections of caries. Even very small lesions are detected at the earliest stage, enabling you to protect and preserve the tooth substance.

DIAGNOdent is an extremely accurate and reliable adjunct for the detection of subsurface caries.

It removes the guesswork that accompanies many treatment decisions regarding questionable areas, such as stained or discolored grooves.

Advantages1) Accurate - Over 90% accurate in detecting lesions not

detectable with an explorer or bitewing X-rays.

2) Safe - Uses light energy - no X-ray exposure.

3) Poses no danger to staff and patients.

4) Painless, non-invasive examination for patients.

5) Dental caries can be located and quantified at the earliest

possible stages of decay.  This greatly reduces both the

amount of tooth structure that needs to be removed and the

possibility of incorrectly diagnosing decay when it actually

does not exist.

The Diagnodent is a pen-like probe that sends a safe,

painless laser beam into the tooth and checks its

health.

A number scale and an alarm will signal when there

are signs of hidden decay.

This allows us to determine if decay is hidden

beneath the apparently healthy tooth surface.

This technology allows us to catch tooth decay at an

earlier stage, before the tooth is destroyed from the

inside out.

[2] Digital Imaging Fiber-Optic Transillumination

Digital imaging fiber-optic transillumination [DIFOTI] uses

visible light, not ionizing radiation, and is approved for the

detection of caries on:

1) Approximal, smooth surfaces

2) Occlusal surfaces

3) Recurrent caries.

DIFOTI uses the scattering of light by

carious tissue as a method of distinguishing

it from healthy enamel

Light is passed through the tooth, collected

using a camera, and the image displayed on a

computer screen.

The system has a choice of mouth pieces.

1) The interproximal mouthpiece

(Detecting interproximal caries) shines light from either

the buccal or lingual surface, which is imaged on the

opposite side by a CCD camera in the handpiece.

2) The occlusal mouthpiece

(Detecting occlusal caries) gathers light originating

from the buccal and lingual tooth surface.

In both cases, a standard personal computer with an

image capture card allows the image to be viewed on

a monitor.

The carious part of the tooth appears dark against a

light background of the healthy tooth

The DIFOTI system was not able to determine the depth

of lesions in contrast to radiographs.

FOTI equipment

Example of FOTI on a tooth. (a) Normal clinical vision, (b) with FOTI.

Advantages:

1) Has superior sensitivity over traditional radiography and can

detect early lesion.

2) Images is produced very fast as there is no need for

processing.

3) No Radiation is needed. Disadvantages:

4) Difficult to distinguish carious lesion from enamel hypo‐

mineralization and deeply stained fissures.

5) Doesn’t show the depth of the lesion thus difficult to

monitor the progress of any preventive regime.

  Early Decay

  Late Decay

Leaking Filling 

The quantitative light-induced fluorescence (QLF)

system uses a blue light (∼488nm wavelength) to

illuminate the tooth, which normally fluoresces a green

color.

Teeth should be dried for 15s to produce more

consistent readings.

Carious lesions appear as dark areas.

[3] Quantitative Light-Induced Fluorescence

QLF Equipment. (a) The QLF unit light box,demonstrating the handpiece and liquid light guide

(b) A close-up of the intra-oral camera featuring a disposable mirror tip that also acts as an ambient light shield.

Tooth image without QLF Tooth image with QLF

The reflected light is passed through a yellow

filter, and after processing is displayed in real

time on a computer monitor.

A decrease in fluorescence is associated

with tooth demineralization and lesion

severity.

Images can be captured and analyzed to provide

measurements of:

1) Lesion area

2) Lesion depth

3) Lesion volume

This information is very useful for monitoring

enamel lesions on a longitudinal basis to see how

they respond to a preventive regime.

Disadvantage

1) QLF will only detect enamel demineralization

and cannot distinguish between caries limited

to the enamel and that which extends into

dentin

2) QLF cannot distinguish between decay and

hypoplasia.

Advantage 1) Patient education, and preventive clinical practice.

2) QLF can be used successfully to detect early secondary

caries around amalgam and tooth-colored filling

materials.

3) Demineralization of enamel adjacent to orthodontic

brackets

4) QLF can be used to detect enamel demineralization and

the success of a subsequent fluoride remineralization

regime.

[4] Electrical Conductance

This method uses the increase in electrical

conductivity of a tooth when it is demineralized.

Conductivity is measured from the enamel surface

to a ground electrode, and any increase in

conductivity is due to microscopic demineralized

spaces within the enamel.

The ECM device (Version 4) and its clinical application. (a) The ECM machine, (b) the ECM handpiece, (c) site specificmeasurement technique, (d) surface specific measurement technique.

[5] Ultrasound Techniques

The principle behind the technique is that sound

waves can pass through gases, liquids and solids

and the boundaries between them.

Images of tissues can be acquired by collecting the

reflected sound waves.

Disadvantages :Only for superficial enamel lesions

Ultrasonic Caries Detector

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