Laser research: Odontology, abstract and studies

Reference

Photomedicine and Laser Surgery Volume 30, Number 5, 2012

Laser GaAlAs (k860 nm) Photobiomodulation for the Treatment of Bisphosphonate-Induced Osteonecrosis of the Jaw

Milena Go´es da Guarda, D.S.,1 Gardeˆ nia Matos Paraguassu´ , M.Sc.,2 Naiadja Santana Cerqueira, D.S.,1 Patrı´cia Ramos Cury, Ph.D.,3 Jener Gonc¸ alves Farias, Ph.D.,4 and Luciana Maria Pedreira Ramalho, Ph.D.5


Abstract

Objective: The aim of this article is to report a case of bisphosphonate-induced osteonecrosis (ONJ-BP) of the jaw treated by curettage of the necrotic bone, low-level laser therapy (LLLT), and antibiotic therapy.

Background data: ONJ-BP is characterized by painful ulcerations of the oral mucosa, is prone to bone necrosis that does not heal within 8 weeks after diagnosis, and is often difficult to treat. No definitive standard of care has been established for ONJ-BP. LLLT improves wound healing, relieves pain, and appears to be a promising treatment modality for patients with ONJ-BP.

Methods: An 82-year-old man taking intravenous bisphosphonate presented with ONJ-BP after tooth extraction. The patient was treated by LLLT using a GaAlAs diode laser with the following settings: wavelength, 860 nm; 70mW; continuous wave; and spot size 4mm2. An energy density of 4.2 J/cm2 per point was applied in a punctual contact manner every 48 h for 10 days, in association with antibiotic therapy and curettage of the necrotic bone. Reduction in painful symptoms was reported after the second irradiation session, and tissue healing was complete at the end of the third week following oral curettage. The patient was followed up for 12 months and exhibited good oral health and quality of life.

Conclusion: The therapeutic protocol used in this study had a positive effect on tissue healing and remission of painful symptoms, resulting in better oral health and quality of life for the patient.


Photomedicine and Laser Surgery Volume 30, Number 3, 2012

Effect of Adjunctive Low Level Laser Therapy (LLLT) on Nonsurgical Treatment of Chronic Periodontitis

Mona Makhlouf, D.D.S., Ph.D.,1 Mushira M. Dahaba, D.D.S., Ph.D.,2 Jan Tune´ r, D.D.S.,3
Sohair A. Eissa, M.D., Ph.D.,4,* and Tarek A.-H. Harhash, B.Sc., M.Sc., Ph.D.5


Abstract

Objective: The aim of this split-mouth, double blinded, short-term, controlled clinical trial was to study the effect of low-level laser therapy (LLLT) as an adjunct to scaling and root planing (SRP) for treatment of chronic periodontitis.

Background data: LLLT is reported to improve the outcome of traditional SRP, but the evidence is still weak.

Methods: Sixteen patients with a probing pocket depth (PPD) of 4–6mm involving at least three teeth in each quadrant were recruited for the study. Afterwards, SRP quadrants were randomly assigned for 10 sessions of LLLT.

Results: Results showed that when compared to sites treated with SRP alone, those treated with SRP + LLLT (10 sessions, 830 nm, 100mW, 3 J per point, 3 J/cm2) exhibited greater reductions in PPD at 5 weeks and 3 months but not at 6 months. Further, SRP + LLLT-treated sites had a statistically significant increase in mean radiographic bone density when comparing 6- and 12-month data and overall from baseline to 12 months. There was a trend to reduce interleukin (IL)-1b but the difference between control and laser sites was not statistically significant.

Conclusion: SRP combined with LLLT improved radiographic bone density and short-term PPD reduction in patients with chronic periodontitis, but did not significantly affect either the gingival crevicular fluid of IL-1b or the gingival or plaque index.


Photomedicine and Laser Surgery Volume 29, Number 8, 2011

Influence of Superpulsed Laser Therapy on Healing Processes Following Tooth Extraction

Marco Mozzati, D.D.S.,1 Germana Martinasso, Ph.D.,2 Nadia Cocero, D.D.S.,1 Renato Pol, D.D.S.,1 Marina Maggiora, Ph.D.,2 Giuliana Muzio, Ph.D.,2 and Rosa Angela Canuto, M.D.2


Abstract

Objective: This research studied the effects of laser therapy on healing processes following tooth extraction in healthy human subjects, evaluating some inflammation, osteogenesis, and clinical parameters.

Background data: Alveolar healing following tooth extraction is a complex repair process involving different types of tissues, including epithelium and bone. Therefore, it can be advantageous to use techniques able to influence the healing of all tissues.

Methods: Ten healthy human subjects with indications for bilateral tooth extraction entered the split-mouth study. The subject/patient becomes his/her own control, thereby eliminating all individual differences in response to laser treatment. This consisted of: 904-nm laser, 33W peak power, 30 KHz, 200 ns, average power 200mW, illuminated area 1 cm2, 200mW/cm2, 15 min, 180 J, 180 J/cm2. In each patient, one post-extraction site was treated with laser radiation, whereas the other was left untreated as a control. Softtissue specimens were removed from the extraction site before tooth extraction (T0) and 7 days after from extraction (T7); expression of inflammatory and osteogenesis parameters was evaluated on these specimens. The clinical parameter ‘‘pain’’ was evaluated for each subject.

Results: Superpulsed laser irradiation prevented the increase of interleukin (IL)-1b, IL-6, IL-10, and cyclooxygenase-2 (COX-2), and induced an insignificant increase in collagen at 7 days after extraction, versus levels on day of extraction; no changes were found in the other parameters examined. Patients reported less pain at the site treated with superpulsed laser irradiation than at the control site.

Conclusion: This study suggests that superpulsed laser irradiation may be a treatment of choice for patients scheduled for tooth extraction, as it provides clinical efficacy, is safe and well tolerated, and is able to prevent inflammation.


Photomedicine and Laser Surgery Volume 29, Number 4, 2011

Low-Level Laser Therapy in Burning Mouth Syndrome Patients: A Pilot Study

Ilka Tiemy Kato, Ph.D.,1 Vivian Diane Pellegrini, M.Sc.,2 Renato Araujo Prates, Ph.D.,1 Martha SimoËœes Ribeiro, Ph.D.,1 Niklaus Ursus Wetter, Ph.D.,1 and Norberto Nobuo Sugaya, Ph.D.2


Abstract

Objective: The aim of this study was to investigate the effect of low-level laser therapy (LLLT) on the treatment of burning mouth syndrome (BMS). In addition, the laser effect was compared on the different affected oral sites.

Methods: Eleven subjects with a total of 25 sites (tongue, lower lip, upper lip, and palate) affected by a burning sensation were selected. The affected areas were irradiated once a week for three consecutive weeks with an infrared laser (790 nm). The probe was kept in contact with the tissue, and the mucosal surface was scanned during the irradiation. The exposure time was calculated based on the fluence of 6 J/cm2, the output power of 120mW, and the area to be treated. Burning intensity was recorded through a visual analog scale before and after the treatment and at the 6-week follow-up. The percentage of the improvement in symptoms was also obtained.

Results: Burning intensity at the end of the laser therapy was statistically lower than at the beginning ( p<0.01). Patients reported an 80.4% reduction in the intensity of symptoms after laser treatment. There was no statistical difference between the end of the treatment and the 6-week follow-up, except for the tongue site.

Conclusion: Under the investigated parameters, infrared LLLT proved to be a valuable alternative for BMS treatment, providing a significant and lasting reduction in symptoms.


Photomedicine and Laser Surgery Volume 29, Number 1, 2011

The Prevention of Induced Oral Mucositis with Low-Level Laser Therapy in Bone Marrow Transplantation Patients: A Randomized Clinical Trial

Geisa Badauy Lauria Silva, D.D.S., M.Sc.,1 Elismauro Francisco Mendonc¸a, D.D.S., M.Sc., Ph.D.,2 Cesar Bariani, M.D.,1 Heliton Spindola Antunes, D.D.S., M.Sc.,3 and Maria Alves Garcia Silva, D.D.S., M.Sc., Ph.D.2


Abstract

Background data and Objective: Patients who have received high doses of chemotherapy, either alone or in combination with total body irradiation often cite oral mucositis (OM) as the most debilitating side effect. The aim of this study was to investigate the clinical effects of low-level laser therapy (LLLT) on the prevention of conditioning-induced OM in hematopoietic stem cell transplantation (HSCT).

Methods: We randomized 42 patients who underwent autologous or allogeneic HSCT. A low-level InGaAlP diode laser was used, emitting light at 660 nm, 40mW, and 4 J/cm2. An evaluation of OM was carried out using the World Health Organization scale.

Results and Conclusion: In the LLLT group, 57.1% of patients had an OM grade 0, 9.6% had grade 1, and 33.3% had grade 2, whereas in the control group, only 4.8% of patients were free of OM (grade 0). Our results indicate that the preventive use of LLLT in patients who have undergone HSCT is a powerful instrument in reducing OM incidence.


Photomedicine and Laser Surgery, Aug 2006, Vol. 24, No. 4: 522-527

Arthralgia of the Temporomandibular Joint and Low-Level Laser Therapy

Dr. H. Fikáčková, M.D.
Institute of Biophysics and Informatics, 1st Medical Faculty, Charles University, Prague, Czech Republic. Department of Anatomy and Biomechanics, Faculties of Physical Education and Sports, Charles University, Prague, Czech Republic.

T. Dostálová, M.D., Ph.D., Dr.Sci., M.B.A. Department of Stomatology, 1st Medical Faculty, GFH, Charles University, Prague, Czech Republic.

R. Vošická, D.D.S. Department of Stomatology, 1st Medical Faculty, GFH, Charles University, Prague, Czech Republic.

V. Peterová, M.D., Ph.D. Radiodiagnotics Clinic, MR Department, 1st Medical Faculty, Charles University, Prague, Czech Republic.

L. Navrátil, M.D., Ph.D.
Institute of Biophysics and Informatics, 1st Medical Faculty, Charles University, Prague, Czech Republic. Department of Radiology and Toxicology, Faculty of Health and Social Sciences, South Bohemia University, Ceske Budejovice, Czech Republic.

J. Lesák Institute of Theoretic and Applied Mechanics, Academy Sciences of the Czech Republic, Prague, Czech Republic.


Abstract

Objective: This case report describes the treatment of a patient with arthralgia of the temporomandibular joint (TMJ) caused by disc displacement.

Background data: The goal of the treatment of TMJ arthralgia is to decrease pain by promotion of the musculoskeletal system's natural healing ability.

Methods: This report describes the complex treatment of TMJ arthralgia. Low-level laser therapy (LLLT) was chosen for its anti inflammatory and analgesic effects. Laser therapy was carried out using the GaAlAs diode laser with an output power of 400 mW, emitting radiation with a wavelength of 830 nm, and having energy density of 15 J/cm2; the laser radiation was applied by contact mode on four targeted spots in 10 sessions. Physiotherapy was recommended to this patient to prevent the injury of intra articular tissue caused by incorrect movement during opening of the mouth. Splint stabilization and prosthetic treatment were used to reduce overloading of the TMJ, resulting from unstable occlusion and to help repositioning of the dislocated disc.

Results: Five applications of LLLT led to decrease of pain in the area of the TMJ on the Visual Analog Scale, from 20 to 5 mm. The anti-inflammatory effect of the laser was confirmed by thermographic examination. Before treatment, the temperature differences between the areas of the normal TMJ and TMJ with arthralgia was higher than 0.5°C. However, at the conclusion of LLLT, temperatures in the areas surrounding the TMJ were equalized.

Conclusion: This study showed the effectiveness of complex non-invasive treatment in patients with arthralgia of the TMJ. The analgesic and anti-inflammatory effects of LLLT were confirmed by infrared thermography.


Photomedicine and Laser Surgery, Jun 2006, Vol. 24, No. 3: 358-365

Effect of GaAIAs Laser on Reactional Dentinogenesis Induction in Human Teeth

Adriana Nayme Segovia Ferreira, M.Sc. Group of Biomolecular Spectroscopy, Institute of Research and Development (IP&D), University of Vale do Paraíba (UNIVAP), São José dos Campos, Brazil.

Landulfo Silveira Jr., Ph.D. Group of Biomolecular Spectroscopy, Institute of Research and Development (IP&D), University of Vale do Paraíba (UNIVAP), São José dos Campos, Brazil.

Walter João Genovese, Ph.D. School of Dentistry, University of Cruzeiro do Sul (UNICSUL), São Paulo, Brazil.

Vera Cavalcante de Araújo, Ph.D. Department of Oral Pathology, School of Dentistry, São Paulo University (FOUSP), São Paulo, Brazil.

Lúcio Frigo, Ph.D. School of Dentistry, University of Cruzeiro do Sul (UNICSUL), São Paulo, Brazil.

Ricardo Alves de Mesquita, Ph.D. Department of Oral Pathology, School of Dentistry, São Paulo University (FOUSP), São Paulo, Brazil.

Eduardo Guedes, M.Sc.
School of Dentistry, University of Cruzeiro do Sul (UNICSUL), São Paulo, Brazil.


Abstract

Objective: This study investigated the biomodulatory effect of the gallium- aluminum-arsenate laser (GaAlAs) in pulp cells on reactional dentinogenesis, and on the expression of collagen type III (Col III), tenascin (TN), and fibronectin (FN) in irradiated dental tissues and controls (not irradiated).

Background data: Several studies suggest a biomodulatory influence of low-intensity laser radiation in the inflammatory and reparative processes of biological tissues.

Methods: Sixteen human premolar teeth were selected (after extraction due to orthodontal reasons) and divided into irradiated and control groups. Black class V cavity preparations were accomplished in both groups. For the irradiated group, GaAlAs laser (670 nm, 50 mW) with an energy density of 4 J/cm2 was used. Soon after, the cavities were restored with a glass ionomer and the extractions made after 14 and 42 days.

Results: Histological changes were observed by light microscopy; less intense inflammatory reaction in the irradiated group was found when compared to the controls. Only the irradiated group of 42 days exhibited an area associated with reactional dentinogenesis. After immunohistochemical analysis by the streptoavidin-biotin complex (SABC) method, the expression of Col III, TN, and FN was greater in the irradiated groups.

Conclusion: Our results suggest that a GaAlAs laser with energy density of 4 J/cm2 and wavelength of 670 nm caused biomodulation in pulp cells and expression of collagen, but not collagen of the extracellular matrix, after preparation of a cavity

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Effect of low-level GaAlAs laser irradiation on the proliferation rate of human periodontal ligament fibroblasts: an in vitro study.

Kreisler M, Christoffers AB, Willershausen B, d'Hoedt B.
Department of Oral Surgery, Johannes Gutenberg-University, Augustusplatz 2, 55131 Mainz, Germany. matthiaskreisler@web.de
J Clin Periodontol. 2003 Apr;30(4):353-8.


Abstract

Objective: The aim of this in vitro study was to evaluate a potential stimulatory effect of low-level laser irradiation on the proliferation of human periodontal ligament fibroblasts (PDLF)

Methods: PDLF obtained from third molar periodontal ligaments were cultured under standard conditions and spread on 96-well tissue culture plates. Subconfluent monolayers were irradiated with an 809-nm diode laser operated at a power output of 10 mW in the continuous wave (cw) mode at energy fluences of 1.96- 7.84 Jcm-2. The variable irradiation parameters were the time of exposure (75-300 s per well) and the number of irradiations (1-3). After laser treatment, the cultures were incubated for 24 h. The proliferation rate of the lased and control cultures was determined by means of fluorescence activity of a reduction-oxidation (REDOX) indicator (Alamar Blue Assay) added to the cell culture. Proliferation, expressed in relative fluorescence units (RFU), was determined 24, 48 and 72 h after irradiation.

Results: The irradiated cells revealed a considerably higher proliferation activity than the controls. The differences were significant up to 72 h after irradiation (Mann-Whitney U-test, p<0.05).

Conclusion: A cellular effect of the soft laser application is clearly discernible. Clinical studies are needed to evaluate whether the application of low-level laser therapy might be beneficial in regenerative periodontal therapy.


The Effects Of Low Level Laser Irradiation On Osteoblastic Cells

Coombe AR, Ho CT, Darendeliler MA, Hunter N, Philips JR, Chapple CC, Yum LW.
Discipline of Orthodontics, Faculty of Dentistry, University of Sydney, New South Wales,Australia;
Institute of Dental Research, United Dental Hospital, New South Wales, Australia.
Clin Orthod Res. 2001 Feb;4(1):3-14.


Low level laser therapy has been used in treating many conditions with reports of multiple clinical effects including promotion of healing of both hard and soft tissue lesions. Low level laser therapy as a treatment modality remains controversial, however. The effects of wavelength, beam type, energy output, energy level, energy intensity, and exposure regime of low level laser therapy remain unexplained. Moreover, no specific therapeutic window for dosimetry and mechanism of action has been determined at the level of individual cell types. The aim of this study was to investigate the effects of low level laser irradiation on the human osteosarcoma cell line, SAOS-2.

The cells were irradiated as a single or daily dose for up to 10 days with a GaAlAs continuous wave diode laser (830 nm, net output of 90 mW, energy levels of 0.3, 0.5, 1, 2, and 4 Joules).

Cell viability was not affected by laser irradiation, with the viability being greater than 90% for all experimental groups. Cellular proliferation or activation was not found to be significantly affected by any of the energy levels and varying exposure regimes investigated. Low level laser irradiation did result in a heat shock response at an energy level of 2 J. No significant early or late effects of laser irradiation on protein expression and alkaline phosphatase activity were found. Investigation of intracellular calcium concentration revealed a tendency of a transient positive change after irradiation. Low level laser irradiation was unable to stimulate the osteosarcoma cells utilised for this research at a gross cell population level. The heat shock response and increased intracellular calcium indicate that the cells do respond to low level laser irradiation. Further research is required, utilising different cell and animal models, to more specifically determine the effects of low level laser irradiation at a cellular level. These effects should be more thoroughly investigated before low level laser therapy can be considered as a potential accelerator stimulus for orthodontic tooth movement.


Patients with moderate chemotherapy-induced mucositis: pain therapy using low intensity lasers.

Nes AG; Posso MB
International nursing review; VOL: 52 (1); p. 68-72 /200503/
Buskerud University, Drammen, Norway. s-oddmun@online.no


Abstract

Objective: To investigate the effect of LLLT on pain relief among patients who have developed COM.

Background data: Intensive cancer therapy normally affects malignant and normal cells with high replication rates. Cells in the gastrointestinal tract are therefore commonly affected by cytotoxins. This often results in the development of chemotherapy-induced oral mucositis (COM). COM is the inflammatory response of the oral mucous membrane to the chemotherapy drugs. Low level laser therapy (LLLT) has proved to be effective in treating and repairing biologically damaged tissue and to reduce pain. LLLT has also proven to be an efficient method for the prevention of oral mucositis.

Methods: The study was performed as a clinical test with a sample consisting of 13 adult patients receiving oncology treatment. The patients were treated during a 5-day period, and the pain was measured before and after each laser application. The laser used was an AsGaAl, with a wavelength of 830 nm and a potency of 250 mW. The energy given was 35 J cm(-2).

Analysis: The results were analysed using the Wilcoxon test.

Results: There was a significant (P = 0.007) 67% decrease in the daily average experience of pain felt before and after each treatment, confirming that LLLT can relieve pain among patients who have developed COM.

Study Limitations: The low number of COM patients at the hospital did not allow a control group to be included in the study, and therefore the results contain a potential placebo effect.

Implications For Nursing Care: The most important benefit the authors consider to be the value for the patients of better and quicker treatment with a drastic reduction in painful mucositis.


Low-level laser for prevention and therapy of oral mucositis induced by chemotherapy or radiotherapy.

Genot MT; Klastersky J
Current opinion in oncology; VOL: 17 (3); p. 236-40 /200505/
Laboratoire d'Investigation Clinique H.J. Tagnon, Institut Jules Bordet, Centre des Tumeurs, Université Libre de Bruxelles, Bruxelles, Belgium.


Abstract

PURPOSE OF REVIEW: Oral mucositis is a common morbid condition associated with chemotherapy or radiotherapy for which there is no standard prophylaxis or treatment. There is increasing evidence that the use of low-level laser can reduced the severity of mucositis associated with chemotherapy or radiation therapy. The purpose of this review is to examine the available evidence for it.

RECENT FINDINGS: For most approaches commonly used to prevent or treat chemotherapy-associated or radiotherapy-associated oral mucositis, a recent panel of experts could not find sufficient levels of evidence to recommend or suggest their use. As for low-level laser therapy, the results are difficult to assess and compare because of interoperator variability and because clinical trials are difficult to conduct in that field. Nevertheless, there is accumulating evidence in support of low-level laser therapy.

SUMMARY: On the basis of literature data, it is reasonable to conclude that the evidence that low-level laser therapy may be useful in decreasing the severity of chemotherapy-associated or radiotherapy-associated mucositis is substantial, even though there have been few controlled studies in the field of prevention.


Low-level laser therapy after molar extraction

Hana Kucerováa, Tatjana Dostálováa, Lucie Himmlováa, Jirina Bártováa, Jirí Mazánekb

Institute of Dental Research - General Medical Hospital, Vinohradská 48, 120 60 Prague 2, Czech Republic, E-Mail: dostalova@vus.cz
First Medical Faculty of Charles University Prague, Czech Republic


ABSTRACT

The aim of the study was to evaluate the different frequencies of low-level laser radiation (diode - 670 nm and Helium-Neon 632,8 nm) on healing process after human molar extractions. Frequencies of 5 Hz, 292 Hz and 9000 Hz were used in experiments. Monitoring of secretory IgA and albumin level in saliva and changes in bone density were used as objective markers of biostimulatory effect. Subjective evaluation of therapy was observed using scale (from - negative therapeutic effect; ++++ excellent treatment effect).

Changes of sIgA, albumin levels and bone density were compared in group of 150 patients (non-laser therapy - 30 patients). Differences in levels of the saliva markers (sIgA and albumin) were found to be significant comparing irradiated and non-irradiated groups, as well as comparing groups irradiated by various modulatory frequencies.

It was observed significant differences between increase of sIgA res. albumin and subjective treatment feelings. Bone density after extraction and six-months after surgical treatment was examined using the dental digital radiovisiography. There were detected no significant differences between bone density in irradiated and non-irradiated groups perhaps due to our used therapy diagram.

Keywords: dentistry, low-level laser radiation, secretory IgA, albumin


INTRODUCTION

Extractions of teeth are a part of the dentist's everyday work in his office. It exists many reason for tooth extraction e.g. carries, periodontal diseases, retention or semi-retention tooth etc. After extraction we observe the wound and wound healing is one of the fundamental biological processes allowing the preservation of organism after tissue damage 1,2. Regeneration takes place in three overlapping phases 3.

  • Inflammatory phase: lasts several hours, the damaged tissue is infiltrated with the leukocytes and makrophages infiltration and fibroblasts migration, which also occurs and lasts from 1 to 3 days
  • Proliferation phase: between second and fourth day - neovascularisation, type III collagen synthesis occurs between day 2 and 16.
  • Tissue reconstruction phase: in day 9 to 60 the type III collagen is replaced with type I, the amount of blood vessels is reduced and the reconstruction of fibrous tissue than continues for 6 to 12 months3.

After the extraction the open space of spongiosis is filled with blood clot. The vein re-growth is followed by cells from healing bone marrow. These cells are changed to osteoblasts. The bone is gradually strengthened by lamellar bone. This primary spongiosis structure is, depending on the local conditions, transformed into compact cortical orlamellar bone. The formation of cortical layer, secondary spongiosis and marrow spaces takes approximately 4 months. The final phase of bone differentiation then takes place, where bone is re-modeled into Haversian systems and secondary osteons appear. The re-modellation proceeds from the defect bottom and edges into the central part of the wound. In the extraction pocket the neovascularisation starts. The oxygen supply increases. The oxygen is needed for collagen synthesis and wound epithelisation 4,5 . The components needed for collagen synthesis are provided by phagocytes via damaged tissue. Consecutively, the collagen is transformed into a specific form, the further cell dividing stops, and the veins created by neovascularisation are reduced. The wound surface is epithelised, and the tissue is healed 4.

A normal consequence of using elevators during extractions is that neighouring teeth become sensitive and are difficult to chew with. From literature is known that after extraction the alveolus is irradiated along with the lingual and buccal bony wall 6. Faster coagulation, less postoperative discomfort and quicker healing could be expected 7,8, 9. In our study we decided to objectively evaluate the real effect of low-level laser radiation on healing process after human lower molars extraction 1,3,5, 7,8,9,10. The goal of study was to determine the effects of different frequencies on the healing of extraction wounds via monitoring the changes in secretory IgA and albumin levels in saliva before and after extraction and to evaluate the effects of laser therapy on the healing process of the bone wound via comparing the bone density of laser therapy-treated groups of patients and a group who did not receive any laser therapy treatment in comparison with subjective feeling of patients 1,3,8,9,10,11,12,13.


LASER EQUIPMENT

Low-level diode laser, wavelength 670 nm, power output 20 mW and HeNe , wavelength 632,8 nm, output 5 mW were used to laser therapy (Fig. 1). We used the following laser frequencies:

  • Diode laser 670 nm, frequency 292 Hz
  • Diode laser 670 nm, frequency 9000 Hz
  • Diode laser 670 nm, frequency 5 Hz
  • He-Ne laser Biostimul, frequency 5 Hz
  • Control group - no laser radiation.

The use of low-level lasers is currently quite wide-spread in the dentistry offices 2,13. These lasers are usually equipped with not only the continuous beam but also with the adjustable frequency setting. Often enough, they have pre-set Nogier frequencies, Mastalier-adjusted for dentistry (A=292Hz, B=584Hz, C=1168Hz, D=2336Hz, E=4672Hz, F=9344Hz, G=146Hz). The available knowledge in the field of biostimulatory laser therapy do not give a clear-cut answer to the question what is better for the organism: to use continuous beam, to switch among several different frequencies, or to use a beam modulated into an exact frequency. Recommended frequency levels for diagnoses in dentistry that can be found in the literature either are modulated to a exact frequency or do not precise the beam type used : E.g. for the healing of extraction wounds you can find the following options:

  • Smékal, MaÅ¡ková: continuous (CW) beam, 5 Hz
  • Mastelier: 292 Hz - "A" frequency per Nogier
  • 3000-9000 Hz per Navrátil
  • 9300 Hz per the guidebook for Oralaser Oralia Konstanz Switzerland

EXPERIMENTAL ARANGEMENT

We focused on monitoring.150 healthy patients between 18 and 65 years old, after the extraction of their lower molars (reason for extraction: semi-retention of third bottom molars, carries of teeth 48,47,46,36,37,38). All patients, including the control group, were briefly informed about the anti-inflammatory, analgesic, regeneratory, and immunomodulatory effects of the laser before its use. In accordance with the 1964 and 1989 Helsinki Declaration they gave an informed agreement to cooperate on this project. Patients were randomly divided into five groups. The patients in every group were after extraction treated with low-level diode laser or read light (group 5 - placebo effect)

  • Group 1 (30 patients) - low-level diode laser, frequency, 292Hz, (diode GaAIAs, wavelength 670nm, power output 20mW), density 1,5 J/ cm2
  • Group 2 (30 patients) - low-level diode laser, frequency, 9000 Hz, (diode GaAIAs, wavelength 670nm, power output 20mW), density 1,5 J/ cm2
  • Group 3 (30 patients) - low-level diode laser, 670 nm, frequency 5Hz, (diode GaAIAs, wavelength 670nm, power output 20mW), density 1,5 /J cm2
  • Group 4 ( 30 patients) - He-Ne Biostimul laser, wavelength 632,8nm, output 5mW), frequency 5Hz, density 1, 5 J/ cm2
  • Group 5, control (30 patients), was not laser-treated at all following the extraction.

OBJECTIVE AND SUBJECTIVE DETERMINATION OF TREATMENT EFFECT

Extraction procedure

We have applied local anesthesia (Supracain, Léciva, Czech Rep., Mepivastesin, ESPE, BRD) and extracted the molar. We were used scissors and (or) elevators. Immediately after the extraction, we have irradiated the patients in the groups 1 - 4 with the respective lasers and respective frequencies and energy density 1,5 J/cm2 1,9. The alveolus was irradiated along with the lingual and buccal bony wall. We added the dose into the central part of the wound. The patients were then irradiated with laser for next 4 days.


Determining sIgA and albumin levels

An unstimulated saliva sample (approx. 1 - 1,5ml) was received from each patient prior to the treatment and on the fifth day. Quantitative determination of the secretory IgA and albumin was based on the principle of radial diffusion of saliva sIgA or albumin from the circular pit into a layer of agar gel containing monospecific antagonist. The resulting circular precipitate was evaluated after 96 hours, when a final point of immunodiffusion is achieved. The size of the ring is dependent on the concentration of the proving protein, in our case sIgA and albumin. The concentration of the sample is read directly from the reference table in the kit. Usage of the commerce kit Binding Site allows fast determination of sIgA and albumin in the saliva and guarantees reproducibility and standardization of the method. The sIgA and albumin levels after the treatment were referenced against the levels obtained from the first saliva sample and expressed in percent using the test of Student at the significance level P=0,05. The level of the first sample was considered as 100% (Fig.2).


Bone Density

As an additional marker for analysis of laser biostimulatory effect we evaluated the changes in bone density 6 months after extraction. To obtain the X-ray image, we have used the dental digital radiography method (Radio Visio Graph - RVG, Trophy, France). Isometric images were captured to have possibility to compare the measurements via fixed-point measurement method. We can measure up to 7 specific dimensions. The method itself is non-invasive, since it takes only 15% of the radiation exposure to obtain one conventional X-ray picture 14.

For evaluation we have used digital images taken immediately after the extraction and consecutively after 6 months. To capture the integration in the entire area of the extraction wound we have used the method of sliced RVG images, which we have taken laterally through the extraction wound 7. For that reason we have taken 3-5 slices, depending on the extraction bone area. The slices were 2 mm apart. For each slice, we have established density histogram, characterizing the density spread across the slice. Histograms were evaluated using the computer software program Sigma Scan and Sigma Scan Pro (Jandel, Germany) (Fig. 3).


Subjective patient's response to treatment

To evaluate less postoperative discomfort we prepared the special card containing relevant information on the patients: personal and health information, type of tooth and 5 degree scale of patient ´s sensation from - no change to ++++ excellent results:

- no change
+ less postoperative disconfort
++ better subjective feeling
+++ best subjective feeling
++++ exellent result


RESULTS SIgA and albumin levels:

It was found the significant difference between patients irradiated by laser and control group (Graf 1.) The levels of sIgA and albumin increased in comparison to control. Comparison of the control group with the laser therapy treated patients groups irradiated by various frequencies (Graph 2) shows the most significant increase in the case of patients treated with laser frequency 292 Hz, 9000 Hz and for both the albumin levels and sIgA levels and for 5 Hz for sIgA level. Bone density: The results are in graph form, which compiles the density levels of individual slices for patients after extraction and after 6 months as well as the difference between these two periods (Graph 3). The treatment methods we have used (extraction wounds treated with 1,5 J/cm2 load for 4 days following the extraction) have not shown any significant differences in the bone density compared to the control group 12.


Subjective patient's response to treatment

The better patient´s sensation after laser therapy was observed. The patients felt more comfort after laser therapy for all types of laser and different frequencies (Graph 4).


DISCUSSION AND CONCLUSION

The low-level laser has no influence on the process of osseintegration. This effect was observed on fracture healing in rats using He-Ne laser radiation 12. We have not found any differences in the bone density compared to the control group.

Frequencies recommended for wound healing in literature often vary 1,8,9,10

Different frequencies can have varying effect on sIgA and albumin levels 8,9,15. It is therefore important to use frequencies that increase both sIgA and albumin levels or at least don't have a negative effect. We have found significant differences in sIgA and albumin levels between patients exposed to radiation and those who were not.

The highest increase in sIgA and albumin levels were found in the group treated with the frequency of 9000Hz. Increase in the level of markers vs. the control group was found even in groups treated with other frequencies (5Hz, 292Hz).

Laser therapy objectively improves extraction wound healing and can be recommended as a method of choice16,17. We regard healing of extraction wounds with laser as contributory not only due to subjective feelings of patients who accept laser therapy largely positive due to its non-invasiveness and non-painfulness, but also due to the objectively proven changes in sIgA and albumin levels 8,15.


ACKNOWLEDGEMENTS

This research has been supported by the Grant Agency Ministry of Health of Czech Rep. No. 4091-3.

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