Academic advisor: Prof. Ermolaeva L.A.

Saint-Petersburg State University

Department of Dental Therapy

e-mail: [email protected]

Introduction. The theory of laser radiation was founded by Albert Einstein in 1916. 50 years later in 1960 the first ruby-based laser was developed. Active interest of the scientific society provided laser with a chance to be used in all spheres of life, especially in medicine.

Today high intensity diode laser irradiation (HILI) attracts a lot of scientists, but there is still a wide range of issues that should be discussed and studied more carefully.

The purpose is to describe peculiarities and mechanisms of HILI impact on soft tissues of the oral cavity.

Materials and methods. Publications of Russian and international author on HILI action on soft tissues of the oral cavity in the last decade have been studied. Such searching systems as e-library, Scholar Google, PubMed, journal “Laser in Medical Science” were used for the literature review.

Results. The property of laser radiation depends on the quantum generator supply and spectral absorbing ability of tissues. Diode laser radiation (wave length 792-1030 nm) provided by semiconductor is actively absorbed by melanin and hemoglobin. It outlines the sphere of its usage in stomatology by impacting soft tissues [1].

Two basic principles underlies HILI with the light flow of high power (the intensity of laser radiation more than 10 WT/cm). The first is using the laser radiation as scalpel and second one is based on the physicals properties of light [2].

When HILI interacts with soft tissues of oral cavity, the energy of radiation is transformed into the heat and an object is heated locally. In a range up to 43 degrees thermal damages of the tissues are reversible. Water starts to evaporate at 100 degrees and that causes necrosis of some parts of the tissues, at the temperature higher than 300 degrees the process of ablation begins.

Beside the described effects of HILI action on mucous membrane of oral cavity many authors approved the influence of quantum radiation on biophysical and biochemical properties of tissues. HILI features anti-inflammatory anti-bacterial and bacteriostatic effects, stimulates the influence tissues [3].

Using HILI as scalpel is recommended in using of impulse periodical or unceasing mode of contact method with a power ranging from 0,5 to 7 Wt.

Under impulse-periodical mode, the impulses of HILI are followed by pauses during which the tissues close to the zone of the cut have a time to cool down. Thus, the heat damage is prevented [4,5].

When the contact method is used the distal ending of quartz light guide touches the tissue. In the place of contact particles of burnt tissues that absorb the laser radiation rays reflected from tissue stick on the ending of light guide. At that time the ending of light guide is highly heated and the action of laser radiation is completed with the thermal action of glowing fiber ending. Due to this the effectiveness of the action to tissue is rising and level of laser power is falling [7].

According to researches, the absence of exact recommendations for choosing right options of HILI while using them in clinic conditions is caused by errors of wave length of every individual laser unit (+-5 nm), individual features of specular and penetration properties of mucous membranes of every individual patient (its density, structure, surface conditions such as color, smoothness, heat conductivity, heat capacity, microstructure etc.), manual skills of dentist [7].

Conclusion. To sum up, although HILI is widely used in stomatology, some issues about the effect of high – intensity laser radiation on soft tissues of the oral cavity are still open. A laser standard for soft tissues of the oral cavity is required depending on goals set in experiment probation on animals.

References:

1. Е.А. Шахно. Физические основы применения лазеров в медицине. Учебное пособие, СПб, 2012.

2. Григорьянц Л.А., Кулаков А.А., Каспаров А.С., Диодный лазерный скальпель - как современный инструмент хирурга стоматолога // Стоматолог-практик, 2009; 2:10-13.

3. Амирханян, В.А. Буйлин. Лазерная терапия в стоматологии // Триада; Тверь – 2007.

4. Агеева С.А., Минаев В.П. Современные лазерные скальпели как основа внедрения высокоэффективных и стационарозамещающих технологий в оториноларингологии. Национальный медицинский каталог, 2003; 1(2):62-68.

5. Zimmerli G., Jдger K. Применение СО2 лазера в хирургической стоматологии. Квинтэссенция, 2001; 2:61-63.

6. Рошаль Л.М., Брянцев А.В. Использование полупроводникового лазерного скальпеля с длиной волны 0,97мкм в детской лапароскопической хирургии. Бизнес бюллетень, 2004; 1(12).

7. Бургонский В.Г. Теоретические и практические аспекты применения лазеров в стоматологии // Современная стоматология, 2007, 1.