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ميحرلا نمحرلا الله مسب
اليلق لاإ ملعلا نم متيتو ا ام و
ميظعلا الله قدص
Recent trends in operative dentistry
Include the following : 1) Recent trends in caries diagnosis. 2) recent trend in caries preventiopn (1 (2 3) Recent trends in cavity classification.
4) Recent trends in cavity design.
• 5) Recent trends in restorative materials.
6) Recent trends in restorative technique. • • •
Recent trends in caries diagnosis
Introduction
• •
A single test for caries diagnosis usually cannot be used alone, because such test may be insufficient for accurate caries diagnosis.
Recently, many methods and devices have been introduced into the field of dentistry to aid in earlier diagnosis for carious lesions and in turns preserving as much tooth structure as possible.
Recent Methods for Caries Diagnosis
1) Clinical examination methods. - intra-oral camera. - electrical resistance.
- Fiberoptic transillumination.
1.
2.
- Laser Based device.
- Ultrasonic detection.
3.
- Dye penetration method.
2) Radiographic methods.
Clinical examination methods
b) Advanced methods : 1) The intra-oral camera .
Image of the teeth of exceptional quality with improved lighting and magnification appear on a monitor of computer.
It also improve visual access to the dental cavity.
2) Caries detection dye.
this was applied to differentiate between the superficial infected carious dentin and reversibly denatured re-mineralized affected dentine , which could be left without removal.
3) laser based devices : a) laser fluorescence : diagnodent (fig.2).
b) Co2 laser.
a) Laser fluorescence:
this device have two fiber-optic diodes,; one for emits pulsed light of 655 nm wavelength used to scan over the fissure area in a sweeping motion .The other ,used to receives the reflected fluorescent light , where any changes caused by demineralization are assigned as a numeric value. this device works on the fluorescing nature of bacterial metabolic by products .
a) laser fluorescence ( Diagnodent).
• - Healthy tooth structure exhibits little or no fluorescence, resulting in very low reading on the display screen. - If the general numeric data between 5 and 25, indicate initial lesion in the enamel while values greater than that indicate dentinal caries.
b) Co2 laser .
because caries has increased water and carbon contents with decreased minerals, it is very sensitive to Co2 gas laser.
- when caries is exposed to Co2 gas laser its water contents will evaporized leaving black carbonized residue .
4) Digital fiber optic trans-illumination.
it is a qualitative diagnostic methods by which teeth are illuminated through light transmit from lingual surface. - digital fiber optic was introduced to replace the conventional way of fiber optic trans-illumination , where the former can detect the incipient caries, frank caries , and cracks using charged couple receptor. This receptor contains a photocells which convert the photon energy into color values . In this way the caries will appear as shadow on the monitor of computer
5) Electrical caries monitor.
.
• it is based on the electrical conductivity differences between sound dentinal tissues and caries dental tissues. The device has small electrode to hold by patient and another fine point to be placed on the tooth to explore the fissure - the recording dial shows number from 0 -10 when the value exceed 5, this indicate sufficient demineralization .
6) ultra sonic caries detection.
• in dentistry, ultrasound has been used to image the tooth and to find caries lesion on smooth surfaces . - there is a great promise for ultra sound caries detection for approximal surface.
II) Radiographic examination .
a - Traditional x-ray.
• b - Computerized radiograph ( digitizers).
a) Traditional x-ray.
- periapical - bite wing - oclusal.
b) digitizers: - scanning usual radiographs.
- direct: using R.V.G.
- indirect; using Digora.
A)Traditional x-ray
a) Periapical film: radiolucent area .
b) Bitewing x-ray: proximal caries.
c) Occlusal film : occlsion. caries appear as specially to detect • • to detect the teeth in •
B) digitizers
a) Scanning usual radiographs.
analyzing the degree of radiolucency of the carious lesion to estimate its extent by subtracting old from new radiographs.
b) Direct using R.V.G. :
there is no film but a special intra-oral sensor is used instead of the conventional x-ray to transmit the image to a computer monitor.
c) Indirect using Digora :
depends on reusable image plate which contain storage – phosphor based.
when exposed to radiation create a latent image . when this latent image is exposed to a laser scanning it will obtain the stored information.
A A- Bitewing radiograph.
B- Periapical radiograph.
B
Radiographic Appearance of Caries
•
Interproximal lesions
C) Digital Imaging
2-Electrical resistance
2-electrical Resistance
• • The electrical conductivity is directly proportional to the amount of demineralization. It is expressed numerically on a scale from 0-9, indicating the change from sound tooth to an increased degree of demineralization.
Advantages:
• • Very effective in detecting early pit and fissure caries.
It can monitor the progress of caries during caries control program.
Disadvantages: • • • • Presence of enamel cracks may lead to false positive diagnosis.
A sharp metal explorer may cause traumatic defects.
Full mouth examination is time consuming.
It can only recognize demineralization and not the caries specifically.
3-fiber-optical Trans Illumination (FOTI)
3-fiber-optical Trans Illumination (FOTI)
• • Fiber-optical trans illumination was initially designed for the detection of proximal caries.
It works under the principle that since a carious lesion has a lowered index of light transmission , an area of caries appears as a dark shadow that follow the spread of decay through the dentin.
3-fiber-optical Trans Illumination (FOTI)
Marginal ridge fracture Vertical fracture
Advantages : • • • • No hazards of radiation Simple and comfortable to the patient Lesions, which cannot be diagnosed radiographically, can be diagnosed by this method Not time consuming
Disadvantages: • • It is subjected to inter and intra observer variations Difficult to locate the probe in certain areas
4-laser Auto Fluorescence (LAF) B) Diagnodent
4-laser Auto Fluorescence (LAF)
• • •
B) Diagnodent
This instrument is based on the laser auto fluorescence principle but without the use of dyes.
The excitation light is transmitted by an optical fiber to the tooth, and a bundle of nine fibers arranged concentrically around it serves for detection.
The digital display shows quantitatively the detected fluorescence intensity.
A photograph showing diagnodent instrument during caries diagnosis
Recent Methods for Caries Diagnosis
1.
2.
3.
4.
5.
6.
7.
8.
Radiographic methods.
Electrical resistance.
Fiberoptic transillumination.
Laser auto fluorescence.
Ultraviolet illumination.
Endoscopy.
Ultrasonic detection.
Dye penetration method.
8-dye Penetration Method
8-dye Penetration Method
• • Dyes can visualize a subject from its background.
For qualitative assessment, it is sufficient to differentiate colored objects from the non colored ones.
8-dye Penetration Method
Dyes should fulfill the following criteria before being recommended for clinical use: 1.
2.
3.
Absolutely safe for intra oral use.
Specific and stain only the tissues it is intended to stain.
Easily removed and not lead to permanent discoloration.
A) Dyes for Detection Carious Enamel:
• • • Various dyes have been tried to detect carious enamel, each have some advantages and disadvantages.
Procion
dyes stain enamel lesions but the staining become irreversible.
Calcein
dye makes a complex with calcium and remains bound to the lesion.
Brilliant blue
has also been used to enhance the diagnostic quality of fiber-optic trans illumination.
B) Dyes for Detection of Carious Dentin: • • • 0.5% Basic fuchsin in propylene glycol has been proved to be successful in detection of carious dentin.
Basic fuchsin dye was considered to be carcinogenic; therefore it has been replaced by acid red and methylene blue .
Methylene blue is also slightly toxic so acid red is preferred.
Dyes for Detection of Carious Dentin A B
A) Detail of caries in dentin identified with caries detector.
B) Detail of the preparation following caries removal.
Advantages:
It is simple method for caries diagnosis
Disadvantages:
It may compromise the bond strength of bonded restorations
Recent trend in caries prevention.
•
1) Caries vaccine (caroRx).
• - By using tobbaco planets through injecting them with human DNA to produce human proteins which contains a serum immunoglobulin A antibody ( plantibodies).
- Effect of this vaccine lasts for at least 4 months.
2) laser radiation:
- Infrared laser radiation may increase the acid resistance of enamel by melting a thin layer of surface enamel , which cause water evaporation and distribution of minerals in all lasered area .
- This acid resistance can enhanced by fluoride application.
3) healozone :
- ozone deactivates ₉₉ % of the bacteria in 10 sec. - acids from bacteria are thus largely neutralized .
- minerals and fluorides is now easy to supplied .
- re-mineralization process occur within 4 – 12 weeks .
Recent trend of cavity classification
The traditional GV black’s classification It was concerning the site of caries and not the size of lesion.
New classification proposed by 1977 • mount&hume has been introduced at This new classification concern the site and size of the lesion through the following scale.
•
site/stage (si/sta) classification.
size site 1- pit & fissure.
2- contact area 0 No cavity
1.0
2.0
1 minimal 2 moderate 3 enlarged 4 extensive
1.1
2.1
1.2
2.2
1.3
2.3
1.4
2.4
3- cervical
3.0
3.1
3.2
3.3
3.4
Recent trend in cavity preparation.
Minimal invasive a traumatic technique and produced a cavity with small dimensions (conservative design)is the logic concept which go with the general progressions regarding instruments, equipments, and restorative materials.
• The followings are some of advanced tech. used to produce a conservative cavity design.
•
Change the concept
Black(extension for prevention) into the concept of minimal intervention dentistry has evolved as a consequence of our increased of G.V.
understanding of the caries process
and
the development of adhesive restorative materials .
a) Dental caries is a reversible cycle where the initial demineralization can remineralized b) bonding technique allowing for conservative cavity designs
The concept of conservative approach is to remove the defect only without any more extension, with respect all mechanical and biological principles.
1) Air abrasion technique.
- it was developed in 1940, • The first modification was in the last two decades with introduction of kinetic cavity preparation 2000 ( KPC 2000). - too small minute particles are carried to the tooth by a stream of air which precisely spraying away the decay only. -
(2) chemico-mechanical gel(crisolve).
Gel consist of 3 amino acid plus sodium hypochlorite is applied into the decayed area to dissolve and get it easily removed manually using suitable excavator.
•
3) Yag. type laser • used to remove organic and inorganic debris of caries tissue. It vaporizes the carious tissues and left the sound tooth structure. • 4) prefabricated size matching ceramic inlays ( sonic sys).
This system is consist of : • Varying sizes of abrasives tips are operated in oscillating ultrasonic. Movement. This system include standardized ceramic inlays matching the sizes of abrasive tips. • •
Recent trend in restorative materials.
1) Metallic restoration.
a) bonded amalgam.
• - It is a conventional amalgam with 4-META bonding system. - bond strength is low.
• • b) Gallium based silver alloys.
• - They were introduced to the dental field in a trial to replace the mercury containing silver amalgam - Despite of its high polish ability, it has a higher corrosion more than high copper amalgam. - supplied in specially designed capsules and an adhesive bonding to be applied after acid etching.
• • •
Metallic restorations • • 3) mercury-free direct filling alloys • It is based on silver-tin particles coated with silver 4) computer designed amalgam powder: • that can be self welded by compaction to build up a restoration. Depend on the idea that if alloy particle sizes are packed together well , it will be possible to minimize the mercury required for mixing. •
2) Tooth- colored restorations; A- composoite resins:
a) indirect resin composite e.g. articlass and ceromers .
cured extra-orally by post-curing using heat and light. b) B-quartz or mega-fill ceramic inserts: - are an attempt to counteract some of the low of the restoration. • mechanical properties of resin composites by decreasing polymerization shrinkage and increasing wear resistance Beta quartz inserts are formed from silica-based glass which can chemically bond to resin composite by silane coupling agent .
• • •
c) Ormocers: • it is an organically modified ceramics.
• d) smart composite.
- it is an ion-releasing composite material.
- it releases fluoride, hydroxyle, and calcium ions as the pH drops - it inhibit bacterial growth because it include alkaline glass filler.
e) flowable composite resins.
• because they have lower filler volumes .they are used in class V or as a liner under posterior composite f) new polymer composite: • nano-composite is made from tantalum oxide and silica nano- particles fillers incorporated in a liquid crystal matrix.
B) Glass ionomer: • a) Resin modified glass ionomer.
• contain resin more than ionomer.
b) • •