New usage of Er:YAG in the removal of porcelain veneer and crown

This Er:YAG laser system is actually designed to cut tooth, gum tissue and bone. The Er:YAG allows the user to precisely shaping tooth structure (enamel, or dentin). The laser energy used to reverse the adhesive bond. The laser energy passes through the porcelain veneer and interacts with the adhesive layer connecting the veneer to the natural tooth structure. A veneer is porcelain glass so the laser light,energy just passes through it & interacts with the resin glue underneath. We can use the Er:YAG everyday when removing decay instead of the traditional dental drill.
so we can remove the falled porcelain veneer due to marginal leackage and discoloration or deffective porcelain crown ,in very fast manner and without damaging the undernth normal tooth structure.
this is a new use of Er:YAG iu addition to the various useage in dental hard & soft tissue

Laser Caries Prevention

It is widely recognized that Nd:YAG can increase enamel resistance to demineralization; however, the safe parameters and conditions that enable the application of Nd:YAG laser irradiation in  vivo are still unknown. The aim of this study was to determine a dye as a photoabsorber for Nd:YAG laser and to verify in vitro a safe condition of Nd:YAG irradiation for caries prevention. Fiftyeight human teeth were selected. In a first morphological study, four dyes (waterproof India ink., iron oxide, caries indicator and coal paste) were tested before Nd:YAG laser irradiation, under two different irradiation conditions: 60 mJ/pulse and 10 Hz (84.9 J/cm2); 80 mJ/pulse and 10 Hz (113.1 J/cm2). In a second study, the enamel surface and pulp chamber temperatures were evaluated during laser irradiations. All dyes produced enamel surface melting, with the exception of the caries indicator, and coal paste was the only dye that could be completely removed. All irra diation conditions produced temperature increases of up to 615.08 ° C on the enamel surface. Nd:YAG laser irradiation at 60 mJ/pulse, 10 Hz and 84.9 J/cm2 promoted no harmful temperature increase in the pulp chamber (ANOVA, p < 0.05). Among all dyes tested, the coal paste was an efficient photoabsorber for Nd:YAG irradiation, considered feasible for clinical practice. Nd:YAG laser at 84.9 J/cm2 can be indicated as a safe parameter for use in caries prevention.

Centro de Lasers e Aplicações—IPEN/CNENSP, Av. Prof. Lineu Prestes, 2242, ZIP 05508900, São Paulo, Brazil Departamento de Dentística, FOUSP, Av. Prof. Lineu Prestes, 2229, ZIP 05508000, São Paulo, Brazil
Received February 9, 2009

Role of hard tissue lasers in soft tissue ablation

Erbium lasers, by their nature of being well absorbed by water & hydroxyapatite, originally were considered primarily hard tissue lasers. It must remembered that the primary chromophore of the erbium family of lasers is water in the target tissue, and the largest component of soft tissue is water. Laser physics and absorption curves of various tissues have shown that the erbium family of lasers ablate soft tissue by the same mechanism as hard tissue. The laser energy from the infrared beam is converted into local thermal energy, and this energy creates a massive expansion in the target chromophore of water. The resulting micro explosions result in thin layers of tissue ablation. The erbium laser soft tissue removal process results in a ‘‘shaving’ ’ or ‘‘planing’ ’ of the tissue that clinically appears different than the deeper penetrating ablation process seen with soft tissue lasers(Nd:YAG & Diode), its postulated that during the cutting of human mucosa, the Er:YAG targets the water molecules rather than the collagen matrix. The energy causes the water molecules to be heated into steam,which in turn strains and fractures the collagen matrix in the extracellular environment.The depth of penetration of an Er:YAG laser using a 200- to 400 microsecond pulse width is in the range of 5 t o 40 micron. There is as little as 5 micron of residual thermal damage .This penetration depth is different than the soft tissue lasers (diodes , Nd:YAG), where tissue effects can be as deep as 500 micron or more . The collateral damage produced by the Er:YAG laser is minimal because the energy is absorbed in water and thermal damage is small (no charring), which may result in improved healing of the area.  there is less collagen remodeling and, in turn, faster healing with minimal scar tissue presenting after erbium laser soft tissue surgeries.Diode lasers (810–980 nm ), unlike the erbium family, are very well absorbed in melanin and hemoglobin. These wavelengths will pass through water and penetrate much deeper into the soft tissue. Moreover, these wavelengths achieve hemostasis much better than the erbium lasers, which are not well absorbed by these chromophores. The erbium family is not the ideal wave length for soft tissue surgeries in which ideal hemostasis is desired .to enhance the hemostatic effect when working with laser we don't use water spray and also we use the VLP duration .
The degree of difficulty with hemostasis seems to be greatest in cases where the soft tissue initially is inflamed. Although the erbium laser can be used for gingivectomies, gingivoplasties, frenectomies, vestibuloplasties , extensional procedures, crown lengthening, incisions and drainage, implant exposures during second-stage surgery, apthous ulcer palliative treatments, and the removal of melanin pigmentation, the clinician must show care to assure that no collateral thermal damage may occurs in adjacent tissues such as bone, cementum, or dentin due to using the erbium laser for soft tissue procedures

Er:YAG Ablation Of Hard Tissue

Gingivectomy

Conical Sapphire tip

 Recommended power settings for the erbium family of instruments

Enamel: 4–8W (with water SSP,VSP)

Dentin : 2–5W (with water SSP,VSP)

Caries: 1–3W (with water SSP,VSP)

Bone: 1.5–3W (with water SSP,VSP)

Soft tissue : 1–3W (contact without water VLP)

Dr.Zohairy

Dual clinical effect of diode 810 nm in Pulp Exposure

Diode laser 810 nm has a dual clinical effect in pulpcaping:
1-Laser antesepsis
2-Laser Coagulation effect

Laser Antisepsis

Coplete Laser Antisepsis

LaserCoagulation Of Exposed Pulp

Completion of Pulp Capping

Done By Dr.Zohairy
Tajmeel Healthcare centre

What does light therapy actually do

1. Increase vascularity (circulation) by increasing the formation of new capillaries, which are additional blood vessels that replace damaged ones. New capillaries speed up the healing process by carrying more oxygen as well as more nutrients needed for healing and they can also carry more waste products away.
2. Stimulate the production of collagen. Collagen is the most common protein found in the body. Collagen is the essential protein used to repair damaged tissue and to replace old tissue. It is the substance that holds cells together and has a high degree of elasticity. By increasing collagen production less scar tissue is formed at the damaged site.
3. Stimulate the release of adenosine triphosphate (ATP). ATP is the major carrier of energy to all cells. Increases in ATP allow cells to accept nutrients faster and get rid of waste products faster by increasing the energy level in the cell. All food turns into ATP before it is utilized by the cells. ATP provides the chemical energy that drives the chemical reaction of the cell.
4. Increase lymphatic system activity. Edema, which is the swelling or natural splinting process of the body, has two basic components. The first is a liquid part which can be evacuated by the blood system and the second is comprised of the proteins which have to be evacuated by the lymphatic system. Research has shown that the lymph vessel diameter and the flow of the lymph system can be doubled with the use of light therapy. The venous diameter and the arterial diameters can also be increased. This means that both parts of edema (liquid and protein) can be evacuated at a much faster rate to relieve swelling
5. Increase RNA and DNA synthesis. This helps damaged cells to be replaced more promptly.
6. Reduce the excitability of nervous tissue. The photons of light energy enter the body as negative ions. This calls upon the body to send positive ions like calcium among others to go to the area being treated. These ions assist in firing the nerves thereby relieving pain.
7. Stimulate fibroblastic activity which aids in the repair process. Fibroblasts are present in connective tissue and are capable of forming collagen fibers.
8. Increase phagocytosis, which is the process of scavenging for and ingesting dead or degenerated cells by phagocyte cells for the purpose of clean up. This is an important part of the infection fighting process. Destruction of the infection and clean up must occur before the healing process can take place
9. Induce a thermal like effect in the tissue. The light raises the temperature of the cells although there is no heat produced from the diodes themselves.
10. Stimulate tissue granulation and connective tissue projections, which are part of the healing process of wounds, ulcers or inflamed tissue.
11. Stimulate acetylcholine release. Acetylcholine causes cardiac inhibition, vasodilation, gastrointestinal peristalsis and other parasympathetic effects.

What is the Difference between LED’s and LASERS

Light Emitting Diodes (LEDs) are another form of light therapy that is a relatively recent development of the laser industry. LEDs are similar to lasers inasmuch as they have the same healing effects but differ in the way that the light energy is delivered. A significant difference between lasers and LEDs is the power output. The peak power output of LEDs is measured in milliwatts, while that of lasers is measured in watts. However, this difference when considered alone is misleading, since the most critical factor that determines the amount of energy delivered is the duty cycle of the device.

LED devices usually have a 50% duty cycle. That is, the LED pulse is "on" for 0.5 seconds and "off" for 0.5 seconds versus the 2 ten-millionths of a second burst from laser at 1 cycle per second (1 herz). Moreover, LED is "on" 50% of the time and "off" 50% of the time regardless of what frequency setting (pulses per second) is used.

In the majority of lasers on the market, the energy output varies with the frequency setting: the lower the frequency, the lower the output. In the BioScan system on the contrary, the output is constant regardless of frequency. Even in the case of lasers that claim a peak output of 10 watts, because of the very short duty cycle, the average output at the highest frequencies is of the order of about 10 milliwatts. At the lower frequencies, however, the average output plummets into the range of microwatts (1 microwatt = 1000^th of 1 milliwatt).

LEDs do not deliver enough power to damage the tissue, but they do deliver enough energy to stimulate a response from the body to heal itself. With a low peak power output but high duty cycle, the LEDs provide a much gentler delivery of the same healing wavelengths of light

as does the laser but at a substantially greater energy output. For this reason, LEDs do not have the same risk of accidental eye damage that lasers do.

Moreover, LEDs are neither coherent nor collimated and they generate a broader band of wavelengths than do the single-wavelength laser. Non-collimation and the wide-angle diffusion of the LED confers upon it a greater ease of application, since light emissions are thereby able to penetrate a broader surface area. Moreover, the multiplicity of wavelengths in the LED, contrary to the single-wavelength laser, may enable it to affect a broader range of tissue types and produce a wider range of photochemical reactions in the tissue. /stronga

If LED disperses over a greater surface area, this results in a faster treatment time for a given area than laser. The primary reason that BioScan chose the LEDs over lasers is that LEDs are safer, more cost effective, provide a gentle but effective delivery of light and a greater energy output per unit of surface area in a given time duration. They are offered in combinations of visible red light at 660nm and infrared light at from 830nm to 930nm, with 880nm as their average. 

What is Light Therapy

Light therapy has been shown in over 40 years of independent research worldwide to deliver powerful therapeutic benefits to living tissues and organisms. Both visible red and infrared light have been shown to effect at least 24 different positive changes at a cellular level. Visible red light, at a wavelength of 660 nanometers (nm – 1 nanometer is equal to one billionth of a meter), penetrates tissue to a depth of about 8-10 mm. It is very beneficial in treating problems close to the surface such as wounds, cuts, scars, trigger and acupuncture points and is particularly effective in treating infections. Infrared light (904nm) penetrates to a depth of about 30-40 mm which makes it more effective for bones, joints, deep muscle,

The diverse tissue and cell types in the body all have their own unique light absorption characteristics; that is, they will only absorb light at specific wavelengths and not at others. For example, skin layers, because of their high blood and water content, absorb red light very readily, while calcium and phosphorus absorb light of a different wavelength. Although both red and infrared wavelengths penetrate to different depths and affect tissues differently, their therapeutic effects are similar.

Depth of penetration is defined as the depth at which 60% of the light is absorbed by the tissue, while 40% of the light will continue to be absorbed in a manner that is less fully understood. Treating points with Light can have a dramatic effect on remote and internal areas of the body through the stimulation of nerves, acupuncture and trigger points that perform a function not unlike transmission cables

At this time, research has shown no side effects from this form of therapy. Occasionally, one may experience an increase in pain or discomfort for a short period of time after treating chronic conditions. This occurs as the body reestablishes new equilibrium points following treatment. It is a phenomenon that may occur as part of the normal process of recovery.

Light therapy has also been given the name " phototherapy". A study done by the Mayo Clinic in 1989 suggests that the results of light therapy are a direct effect of light itself, generated at specific wavelengths, and are not necessarily a function of the characteristics of coherency and polarization associated with lasers. In a study entitled Low-Energy Laser Therapy: Controversies and New Research Findings, Jeffrey R. Basford, M.D. of the Mayo Clinic’s Department of Physical Medicine and Rehabilitation, suggests that the coherent aspect of laser may not be the source of its therapeutic effect. He states "firstly, the stimulating effects (from therapeutic light) are reported following irradiation with non-laser sources and secondly, tissue scattering, as well as fiber optic delivery systems used in many experiments rapidly degrade coherency . . . Thus any effects produced by low-energy lasers may be due to the effects of light in general and not to the unique properties of lasers. This view is not difficult to accept when it is remembered that wave-length dependent photobiochemical reactions occur throughout nature and are involved in such things as vision, photosynthesis, tanning and Vitamin D metabolism. In this view, laser therapy is really a form of light therapy, and lasers are important in that they are convenient sources of intense light at wavelengths that stimulate specific physiological functions (Lasers in Surgery and Medicine 9:1-5, Mayo Clinic, Rochester, Minnesota, 1989).