In the scientific literature, there are constantly publications on new indications for the use of a laser in endodontics, and most of them are based on data from fundamental research. With the introduction of laser devices for dental use, the question arose about the clinical feasibility of their use in endodontics. Due to the limited access to root canals, very high demands are placed on laser systems. Typically, in all laser systems, beams can be transmitted through fiber optic cable. The effect of laser radiation on the pulp is comparable to the effect of laser light on all other soft tissues of the oral cavity (Frentzen, 1994). However, it should be taken into account that the regenerative capacity of the pulp, limited by hard tissues, is rather low.

The laser can act on the pulp and dentin of the root directly and indirectly. Direct irradiation of the root canal system, such as during vital amputation or canal treatment, can cause overheating, coagulation, carbonation, vaporization or ablation of the pulp and dentin, depending on the type of laser used and its power.

Indirect action of the laser, for example, during the transmission of its energy, as a result of heating and drying of dentin, or due to damage to the processes of odontoblasts by the photoacoustic effect (ultrasound), pulp hyperemia and necrosis occur. Laser-induced hyperemia can, over time, cause the development of a degenerative process in the form of increased dentin formation or partial necrosis. These changes can lead to significant obstruction of the tooth cavity, which complicates endodontic treatment.

Unfortunately, it is currently impossible to assess the delayed side effects of laser use.

Rice. 163. Indications for the use of a laser in endodontics.

The table shows the indications for the use of various types of laser in endodontics.

On right: various dental laser systems.

Rice. 164. Conductors of laser radiation.

On right: fiber optic guide for supplying laser energy to the root canal.

Determination of pulp viability using laser Doppler flowmetry

The effectiveness of laser Doppler flowmetry in the diagnosis of dental diseases has already been proven (Tenland, 1982). This method can also be used to determine the microcirculation in the pulp. Its principle is based on variations in signals from erythrocytes moving under the influence of laser radiation. Variations depend on the direction and speed of movement of red blood cells. For laser Doppler sensing, HeNe or diode lasers are used. Diode lasers are more widely recommended for clinical use due to their deeper penetrating power (750-800 nm). Laser Doppler flowmetry is used in basic research to measure changes in pulp microcirculation under the influence of various stimuli, such as temperature or local anesthetics (Raab, Muller, 1989;

Raab, 1989). This method can also be used to determine the viability of the pulp after injury. However, in order to obtain reproducible reliable data, high technical costs are required.

B.T. Moroz, Dr. med. Sciences, Professor, A.V. Belikov, Candidate of Engineering Sci., I. V. Pavlovskaya, dentist
Complicated forms of caries are common in the practice of a dentist and account for 30% of the total number of dental diseases. The lack of adequate endodontic treatment leads to a high number of complications in the form of chronic odontogenic foci, which cause a change in the body's reactivity and are the reason for tooth extraction due to complicated forms of caries, mainly 2-4 years after treatment. Therefore, the development of new methods of treatment and improvement of existing ones remains one of the urgent tasks not only of dentistry, but also of general medicine.
The main importance in the treatment of complicated forms of caries is the quality of instrumental and drug treatment of the root canal, as well as the degree of its sealing with filling material. (According to Khalil RA., 1994, in 100% of cases there is no root canal sealing when filling it with pastes and cements).
Currently, none of the methods of root canal treatment for complicated forms of caries provides guaranteed quality.
In scientific articles of an experimental and clinical nature, the positive effect of the use of high-intensity laser radiation in endodontic treatment is shown.
The mechanism of action of laser radiation on root dentin and the result of exposure are determined by the type of laser and, above all, by the wavelength.

Currently, lasers with different wavelengths are used in endodontics.

Excimer laser (X-308 nm)

it is used to obtain an antibacterial effect, to remove the "dirty layer". The preparation of root dentin with this laser is less effective than other lasers and conventional burs. Its radiation does not cause significant heating of the tissue, but as a result of an increase in pressure inside the canal up to 20 MPa, a fracture of the root by a shock wave is possible.

Argon laser (X-488 nm; 514.5 nm)

in endodontics it is used little. The radiation from this laser is poorly absorbed by dentin and water. It can be used at the stage of sealing the root canal with a filling material. During photopolymerization of composite materials, its radiation penetrates to a depth of 11 mm, and the total curing time of the material is only about 8 seconds.

CO2 laser (X ~ 10.6 μm)

can be used in endodontics to remove cysts. Its in-channel application is limited due to the impossibility of transmitting radiation through a quartz optical fiber. The search for conducting systems is currently underway.

Erbium laser (X-2.79 μm; 2.94 μm)

effectively removes hard tooth tissues, filling materials, can be used to pass canals with pulp evaporation.

According to electron microscopy, after treatment of the root canal with an erbium laser, its surface is free from the "dirty layer", uneven, with open dentinal tubules. The possibility of cracking in the dentin of the root, the complexity of the transmission of radiation with X ~ 2.94 μm through silica fiber, limits the use of the erbium laser in endodontics.
The radiation of the most promising neodymium and holmium lasers in endodontics can be transmitted through a flexible optical quartz fiber without significant energy losses, which facilitates its intrachannel application along the entire length of the root. The neodymium laser can be considered the best source of radiation for endodontics, given the possibility of its radiation penetrating into the root tissue by 4-10 mm, which increases the volume of the irradiated tissue.
Currently, neodymium laser (X ~ 1.06 μm) is used to remove pulp from the root canal, antibacterial effect. The radiation from this laser forms a modified layer with a recrystallized structure and closed dentinal tubules on the dentin surface.
The in-channel operation of a YAG: Nd laser has a number of difficulties. The energy level required to seal the dentinal tubules and recrystallize the structure can cause cracks in the dentin, and the rise in temperature during radiation can damage the surrounding tissue.
Holmium laser radiation (X-2.09 microns) is well absorbed by pigmented and non-pigmented tissue and is most often used in orthopedics, for incisions, evaporation, soft tissue coagulation, bone ablation.
The lack of sufficient information on the optimal physical parameters of the radiation of neodymium and holmium lasers for use in endodontics was the reason for the search for laser operating modes that form a new modified dentinal surface without generating heat and acoustic waves that destroy the surrounding tissue.
As a result of in vitro studies, an optimal mode of operation of neodymium and holmium lasers was proposed, in which the microhardness and acid resistance of root dentin increase.
According to the conducted scanning electron microscopy, the resulting increase is associated with the modification of the surface of the dentin of the tooth root as a result of laser radiation, ie, the removal of the "dirty layer" and obturation of the dentinal tubules. This allows the use of teeth with highly dilated root canals for fixing an abutment pin or an intra-root inlay, which was previously risky due to the weakened dentinal structure.
It was found that the antibacterial effect of neodymium laser depends on the type of bacteria: the best results were observed for Staphylococcus aureus and epidermalis. These data confirm the results of other studies on the antibacterial effect of the YAG: Nd laser.
It is shown that as a result of intracanal radiation of a neodymium laser, the degree of marginal adherence of the filling material to the root dentin increases, and the effect of hydration processes of the periodontal CSF on the filling material slows down.
It has been established in vitro that the effect of a neodymium laser on root dentin with intracanal use in the optimal mode is possible without a negative effect on the periodontium. It is shown that the use of radiation with air-water cooling is an effective method to reduce the risk of thermal destruction of the tissues surrounding the root.
Thus, the studies carried out have confirmed the promise of using neodymium and holmium lasers for a comprehensive solution to the problems of endodontics. Further clinical study of this new direction for endodontics is needed.

KazNMU named after S.D. Asfendiyarov
Elective "Clinical endodontics"
CDS on the topic:
"Lasers in endodontics. Laser
root canal sterilization "
Prepared by: A.B. Tenilbaeva
Checked by: Tasilova A.B ..
Group: 604-1
Course: VI
Almaty, 2015

Plan:

Introduction
Laser classification
The scientific basis for the use of lasers in
endodontics
Examples of modern dental lasers
Laser action on MF and dentin filings
Indications and contraindications for the use of lasers
QC laser sterilization algorithm
Clinical examples
FAD
PDT mechanism
Algorim FA-sterilization of QC
Clinical examples
Conclusion
List of used literature.

Introduction:

The main reason for the failure of endodontic treatment is
in insufficient treatment of the root canal from persistent
microorganisms
and repeated
recontamination
channel
due to
inadequate
obturation.
Success
distant
results
endodontic treatment depends on several factors such as
the complexity and diversity of the anatomy of root canals and branches
additional branches. Such a complex system does not allow achieving
direct access during biomechanical processing due to
unusual location and small diameter of the channels. Were
proposed new antibacterial approaches for a more complete
disinfection. These new methods also include a high
intensity and photodynamic therapy, which works by
dose-dependent heat release.

Lasers are classified according to
emitted spectrum of light. They can work with
waves of the visible and invisible spectrum, short,
medium and long infrared range. V
according to the laws of optical physics functions
different lasers in clinical practice differ

The first breakthrough in the use of laser in endodontics
happened in the mid-80s when German
researchers Keller and Hibst were able to create a laser on
yttrium-aluminum garnet with erbium (1064 nm)

Various types of lasers are used in endodontics:

Diode. - short infrared range
Nd: YAG lasers are solid laser. As
the active medium is yttrium aluminum
doped garnet ("YAG", Y3Al5O12)
ions of neodymium (Nd). (1064 nm) - short
infrared
Erbium Er: YAG Designed to treat
hard tissues of teeth ((2780 nm and 2940 nm) - average
infrared

SCIENTIFIC BASIS OF USING LASERS IN
ENDODONTIES
Reflection of laser light by tissue. Reflection is a property
beam of laser light fall on the target and be reflected on
nearby objects.
Absorption of laser light by tissue. Absorbed
laser light is converted into thermal energy. On the
absorption is influenced by wavelength, water content,
pigmentation and tissue type.
Scattering of laser light by tissue. Scattered
the laser light is re-emitted at random
direction and ultimately absorbed in a large
volume with a less intense thermal effect. On the
scattering affects the wavelength.
Transmission of laser light by tissue. Transfer is
the property of the laser beam to pass through tissue, not
possessing the property of absorption, and not exert at
this damaging action.

Modes of emission of laser light

Dental products available on the modern market
lasers are self-contained pulsed lasers

Dental diode laser Wiser

Diode laser "KaVo" GENTLEray980 with a wavelength of 980
nm is designed to perform a large spectrum
manipulations in maxillofacial surgery, with
periodontal treatment, during treatment
bacterial infections during endodontic treatment and
root canal preparation (pulp coagulation,
pulpotomy, root canal sterilization)

EFFECTS OF LASER RADIATION ON
MICROORGANISMS AND DENTIN
Endodontic treatment uses
photothermal and photomechanical properties of lasers,
arising from the interaction of different wavelengths and
various parameters of fabrics on which
impact. This is dentin, smeared layer, sawdust,
residual pulp and bacteria in all forms
the aggregate.
Waves of all lengths destroy the cell wall due to
photothermal effect. Due to the nature of the structure
cell wall gram-negative bacteria
break down more easily and with less energy consumption than
gram-positive.
The beam penetrates the dentinal walls to a depth of 1 mm,
providing a disinfecting effect on deep
layers of dentin.

Laser light has a wide range of therapeutic and prophylactic effects:

pronounced anti-inflammatory effect, normalizes
microcirculation,
reduces the permeability of the vascular walls,
possesses fibrin-thrombolytic properties,
stimulates metabolism, tissue regeneration
increases the oxygen content in them
accelerates wound healing
prevents scarring after operations and injuries
Neurotropic
Analgesic
muscle relaxant
Desensitizing
bacteriostatic and bactericidal action
stimulates the immune defense system
reduces the pathogenicity of microflora
increases its sensitivity to antibiotics.

Indications and contraindications for the use of lasers

Indications:
Contraindications:
Dental
diseases in children
dentistry
Diseases
periodontium
Aphthous ulcers
Gingival
hyperplasia
Allergy to
standard
anesthetics
Hypersensitivity
Oncological
diseases
Acute purulent
inflammatory processes
Severe illnesses
heart and postinfarction
period
Complex shapes
vascular diseases
Tuberculosis
Severe degree
diabetes mellitus
Diseases of the blood.

Radiation protection equipment
Dental manipulations with
using a laser require
mandatory use of funds
protection of vision, therefore both the doctor and
patient must wear
special tinted glasses.
To avoid a reflection
laser radiation, it is necessary
remove all reflective and
metal objects.
And since the laser is
fire hazardous, prohibited
direct the beam to clothing and
other fabrics.

Algorithm for laser root canal disinfection:
- after opening the root canal system, extirpation
the pulps determine the working length of the canal;
- for the passage and expansion of the root canal
use the crown down technique with abundant
rinsing with sodium hypochlorite and EDTA treatment;
- the length of the canal is transferred to an endodontic laser
tip (0.4 mm in diameter, 30 mm long);
- the tip light guide is inserted into the dried channel and
set, not reaching 2 mm to the apical narrowing,
then every 0.3 s they emit pulses with a power of 4 W and
duration 5 ms;
- the side walls of the canal are sterilized defocused
beam power 2 W in pulsed mode with
pulse duration 50 ms in 0.2 s at
slow removal of the fiber.

In endodontics, laser irradiation can be performed
prepared dry root canal or through
antiseptic solution, as well as in combination with
photosensitizer.

Clinical examples

1.21 tooth - sterilization of the canal with a diode laser

Enlarged photo

Roentgenogram

2. Chronic granulomatous periodontitis 34, 35

2. Chronic granulomatous
periodontitis 34, 35

Sterilization of the focus and canals with a diode dental laser. The result of treatment after 2 months is a focus of chronic

inflammation is eliminated,
active tissue regeneration

Photodynamic therapy (PDT) - photoactivated
disinfection - has great prospects in endodontics.
It is effective against all microorganisms. This is the method
combined two-component laser therapy,
selective accumulation
photosensitive dye (photosensitizer) in
target cells with their subsequent irradiation with light
specific intensity and wavelength.

Principle
photoactivated
disinfection

PDT methodology in prepared
root canals:
- the introduction of a photosensitizer solution into
root canal for staining microorganisms in
within 1 min;
- rinsing with distilled water,
drying;
- laser irradiation with an endodontic light guide
for the entire length of the root canal, exposure - not Bolonkin V.P. The use of laser therapy in
endodontics / V.P. Bolonkin F. N. Fedorova // Laser
medicine. 2003 Vol. 7. Issue 1 pp. 42-43.
Beer R. An Illustrated Guide to
endodontology / R. Bir, M. A. Bauman. M .: MEDpressinform, 2006.240s.
http://dentabravo.ru/stati/ispolzovanie-lazera/
http://dentalmagazine.ru/nauka/lazery-v-endodontii.html

Laser dentistry is an innovation used by dentists to treat the most demanding patients. The laser in dentistry is one of the safest and most painless methods of treatment due to the fast laser treatment of various types of tissues, the surface of which remains flat and heals faster than with other technologies.

The use of a laser in dentistry eliminates the occurrence of microcracks, infection, it does not create vibration and does not make noise. In addition, a laser can be used to process hard dental tissues in the same amount of time as with a boron, but the treatment is invisible to the patient.

The laser in dentistry is indispensable for the treatment of severe cases that are difficult to cope with using standard equipment. Getting rid of a tooth cyst is more successful with the use of a laser than with traditional methods.

The laser is also used to remove tartar. The use of laser radiation during this procedure has already been recognized as the most effective method: the process takes little time, is painless, the soft tissues of the gums are not injured when deposits are removed.

Laser radiation is also used in the treatment of periodontitis and gingivitis. The laser in dentistry allows you to eliminate pathological soft tissues and all infected microflora. The regeneration of the soft tissues of the alveolar process is faster.

The use of a laser in dentistry: indications and contraindications

Indications

Contraindications

♦ When treating a carisogenic process, since the affected areas of tooth enamel and dentin are removed without negatively affecting the surrounding healthy tissues.

♦ With bleeding gums.

♦ By eliminating unpleasant odor from the oral cavity, which occurs due to the destruction of all pathogenic bacteria.

♦ In the treatment of pulpitis and periodontitis for the treatment of root canals.

♦ To strengthen the gums - periodontal irradiation is performed to create local immunity.

♦ To remove various neoplasms on soft tissues.

♦ When whitening teeth.

♦ When treating a cyst of a tooth, since a more effective treatment of root canals and suppression of a pathological focus is possible.

♦ To relieve hypersensitivity of hard tissues.

♦ For dental implantation.

♦ Severe cardiovascular diseases.

♦ Decreased blood clotting.

♦ Lung pathologies caused by dangerous infectious diseases and functional respiratory disorders.

♦ Malignant neoplasms both in the oral cavity and in the body as a whole.

♦ Disruption of the endocrine system.

♦ High sensitivity of enamel.

♦ Neuropsychiatric disorders.

♦ The recovery period after any surgery.

Types of lasers used in dentistry

The use of a laser in dentistry is based on the principle of selective action of a laser beam on different types of tissues, since a specific structural component of biological tissue absorbs laser radiation in different ways. As we noted above, the role of an absorbing substance, or chromophore, can be played by water, blood, melanin, etc. The specific chromophore determines the type of laser device. The absorption characteristics of the chromophore and the site of application determine the laser energy.

The types of lasers in dentistry depend on characteristics such as pulse duration, discharge, wavelength, penetration depth. There are the following types of lasers:

pulsed dye laser;
helium-neon laser (He-Ne);
ruby laser;
alexandrite laser;
diode laser;
neodymium laser (Nd: YAG);
Goldmium laser (No: YAG);
Erbium laser (Er: YAG);
carbon dioxide laser (CO 2).

Today, laser dentistry centers can be equipped not only with lasers performing a highly specialized function, for example, teeth whitening, but also with devices that combine several types of lasers. For example, these are devices that can work with both hard and soft tissues.

The laser has several modes of operation. It is pulsed, continuous and combined. Depending on the operating mode of the laser, its power, or energy, is selected.

The table below shows the types of lasers in dentistry, the depth of their penetration and the types of absorbing chromophores:

Laser	Wavelength, nm	Penetration depth, μm (mm) *	Absorption chromophore	Types of fabric	Lasers used in dentistry
Nd: YAG Frequency Doubling			melanin, blood
Pulsed dye			melanin, blood
Helium-Neon (He-Ne)			melanin, blood	soft, therapy
Ruby			melanin, blood
Alexandrite			melanin, blood
			melanin, blood	soft, whitening
Neodymium (Nd: YAG)			melanin, blood
Goldmium (Ho: YAG)
Erbium (Er: YAG)				hard (soft) hard (soft)
Carbon dioxide (CO 2)				hard (soft) soft

* The depth of penetration of light h in micrometers (millimeters), at which 90% of the power of the laser light incident on the biological tissue is absorbed

Argon laser. Argon laser wavelengths are 488 nm and 514 nm. The first wavelength indicator is similar to that of curing lamps. However, when exposed to laser light, the rate and degree of polymerization of the reflective materials is significantly increased. Optimal absorption of laser radiation is achieved by melanin and hemoglobin. The argon laser is used in dentistry, surgery and to improve hemostasis.

Nd:YAG laser. The wavelength of the neodymium laser (Nd: YAG) is 1064 nm. Radiation is well absorbed in pigmented tissues and slightly worse in water. This type of laser has been quite popular in dentistry. The neodymium laser is capable of operating in continuous and pulsed modes. A flexible light guide directs laser light to the target tissue.

He-Ne laser. The helium-neon laser in dentistry (He-Ne) is characterized by wavelengths from 610 nm to 630 nm. The radiation from this laser is very well absorbed by tissues and has a photostimulating effect. For this reason, the helium-neon laser is widely used in physiotherapy. In addition, it is available commercially, which allows it to be used not only in medical institutions, but also at home.

CO 2 laser. The carbon dioxide (CO 2) laser has a wavelength of 10,600 nm. Its radiation is perfectly absorbed in water; in hydroxyapatite, absorption occurs at an average level. The carbon dioxide laser cannot be used on hard tissues, as there is a risk of overheating of enamel and bone. Despite the outstanding surgical features of this type of laser, it is being driven out of the dental surgical laser market. This is due to the problem of directing radiation to tissue.

Er: YAG laser. Erbium laser in dentistry (Er: YAG) is characterized by wavelengths of 2940 nm and 2780 nm. The radiation from this laser, which is delivered using a flexible light guide, is perfectly absorbed by water and hydroxyapatite. Erbium laser is the most promising in dentistry because it can be used on hard tissues of the tooth.

Diode laser. The diode laser is a semiconductor laser with a wavelength of 7921030 nm. Radiation is absorbed by the pigment. This type of laser has a positive hemostatic, anti-inflammatory and repair-stimulating effect. Laser radiation is delivered using a flexible quartz-polymer light guide, which allows the surgeon to manipulate hard-to-reach areas. The use of a diode laser in dentistry is characterized by its compactness, ease of maintenance and use. In addition to these advantages, it is worth noting the availability of this device for use in terms of the ratio of the price of the laser and its functionality.

Why is the diode laser the most common in dentistry?

The use of a diode laser is quite popular these days for many reasons. This type of laser has been used for a long time in dentistry. For example, in Europe, no manipulation takes place without its use.

Diode laser distinguishes it from other types of lasers by its large list of indications, low cost, compactness, ease of use in a clinic, high level of safety and reliability. The latter property is achieved through the use of electronic and optical components with a number of moving components. These characteristics, for example, allow hygienists not to be afraid of disrupting the structure of the tooth when eliminating periodontal problems.

Laser radiation with a wavelength of 980 nm is characterized by significant anti-inflammatory, bactericidal and bacteriostatic properties, and also accelerates the recovery period after the procedure.

The diode laser is popular in surgery, periodontics, endodontics. It is in great demand in the field of surgical procedures.

The use of a diode laser is important for procedures that in traditional dentistry are accompanied by severe bleeding, the need for suturing and other negative consequences of surgery.

A diode laser emits coherent monochromatic light with a wavelength of 800 to 980 nm. Radiation is absorbed by a dark medium similar to hemoglobin, therefore, when dissecting tissues with a large number of vessels, the diode laser is irreplaceable.

The use of a diode laser in soft tissue dentistry is characterized by a minimal area of necrosis, which becomes possible as a result of tissue contouring. Their edges retain the position that the doctor specified, which is a significant aesthetic factor. For example, using a diode laser, you can contour the smile, prepare the teeth and take an impression in one visit to the dentist. The use of a scalpel or electrosurgical devices for tissue contouring results in a lengthy tissue healing process and tissue shrinkage before the teeth are prepared and the impression is taken.

The ability to clearly establish the position of the tissue incision edge makes the diode laser popular in aesthetic dentistry. In this area, it is used in soft tissue reconstruction and frenum plasty (frenectomy). This procedure, when using traditional techniques, is accompanied by the need for suturing, which is very difficult to implement, while the use of a diode laser ensures that there is no bleeding, no sutures, as well as a quick and comfortable recovery.

Which laser device should you buy for your dental clinic?

Among the variety of laser devices used in clinical dentistry, there are six main types:

Laser physiotherapy devices with gas emitters (for example, helium-neon, such as ULF-01, Istok, LEER, etc.), semiconductor (for example, ALTP-1, ALTP-2, Optodan, etc.).
Laser device "Optodan", which allows to carry out magneto-laser therapy. For this purpose, a special commercially available magnetic attachment with a power of up to 50 mT is used.
Specialized laser devices of the ALOK type used for intravenous blood irradiation. Recently, however, their popularity has fallen due to the spread of a new patented, highly effective technique for irradiating blood through the skin in the area of the carotid sinuses using the Optodan laser apparatus.
Laser devices for laser reflexology, for example, "Nega" (2-channel), "Contact". The "Optodan" device is also suitable for these purposes when using a special light-guide attachment for reflexology.
New generation laser surgical devices (analogue of a laser scalpel) ("Doctor", "Lancet") with computer control.
Laser technological installations ("Quant", etc.), which are used for the production of dentures.