GaAlAs Diode Laser Research Articles

Drug‐induced gingival enlargement: Biofilm control and surgical therapy with gallium–aluminum–arsenide (GaAlAs) diode laser—A 2‐year follow‐up

Drug-induced gingival enlargement has been reported in patients treated with various types of anticonvulsant drugs, and is generally associated with the presence of plaque, gingival inflammation, and a genetic predisposition. Effective treatment includes daily oral hygiene and periodic professional prophylaxis. However, in some patients, surgical removal of the gingival tissue overgrowth becomes necessary. The patient in this case report was mentally impaired and had severe drug-induced gingival enlargement. This report describes the initial protocol, the gingivectomy, and a 2-year follow-up. A diode laser was used as an effective and safe method to remove the patient's overgrown gingival tissue.

Emg analysis after laser acupuncture in patients with temporomandibular dysfunction (TMD). Implications for practice

The aim of this study was to analyze the effect of low level laser applied to acupuncture points of patients diagnosed with temporomandibular dysfunction (TMD). Ten patients aged between 20 and 50 years were clinically examined with regard to pain and dysfunction of the masticatory system. They received laser applications (GaAlAs diode laser, 780 nm wavelength; 70 mW power output, 35 j/cm(2)) in acupuncture specific points (Ig4, C3, E6, E7) once a week, for ten sessions. The range of jaw movement was registered after each session and visual analogue scale (VAS) was applied. Results were analyzed (SPSS-15.0-Chicago) during the comparison, before and after treatment. Statistical tests showed significant improvements (p < 0.01) in painful symptoms and electromyographic activities of masseter muscles in maximal habitual occlusion after laser applications but no significant improvements (p = 0.05) in measurements of mandibular movements. The laser therapy in specific acupuncture points promoted improvement of symptoms and it may be used as complementary therapy for TMD.

低エネルギーレーザーの疼痛緩和のメカニズム

Low energy lasers are widely used in the treatment of various chronic pain syndromes in dentistry, pain clinics and orthopedics. It is generally agreed that low energy laser irradiation is effective for improving blood circulation, reducing pain and promoting wound healing. Although there have been many fundamental studies on the effects of lasers, the mechanism of laser-induced analgesic effects remains unknown. This report describes the effects of low energy laser irradiation on nerve cells in vitro, and demonstrates the mechanism of analgesic effect. A GaAlAs diode laser (trinpl D, YOSHIDA) and the neurosecretory PC12 cell line were used. After short-term laser irradiation (0.3-0.5 J/cm2) on PC12 cells differentiated by treatment with nerve growth factor, terminals of neurites swelled within a few minutes and the number of synaptic vesicles decreased. After long-term laser irradiation (15.0 J/cm2), synaptic vesicles completely disappeared from the swollen terminals, whereas cell bodies were still well preserved. Some of the cells appeared to be in degeneration and retracted their neurites accompanied with the alteration of F-Actin structures. The laser irradiation induced a temporary increase in intracellular free calcium ion concentration ([Ca2+]i) and enhanced the amplitude of calcium oscillation.Thus, it is clearly demonstrated that the mechanism of laser-induced analgesic effects is that the laser stimulates calcium ion influx and neurotransmitter release, and then degenerates the terminals and processes of neurites, according to the alteration of F-Actin organization. These findings suggest that low energy laser attenuates the sensitivity of nerve cells to painful stimuli and produces analgesic effects.

Effects of low-level laser therapy on human osteoblastic cells grown on titanium

The aim of this study was to investigate the effects of low-level laser therapy (LLLT) by using gallium aluminum arsenide (GaAlAs) diode laser on human osteoblastic cells grown on titanium (Ti). Osteoblastic cells were obtained by enzymatic digestion of human alveolar bone and cultured on Ti discs for up to 17 days. Cells were exposed to LLLT at 3 J/cm2 (wavelength of 780 nm) at days 3 and 7 and non-irradiated cultures were used as control. LLLT treatment did not influence culture growth, ALP activity, and mineralized matrix formation. Analysis of cultures by epifluorescence microscopy revealed an area without cells in LLLT treated cultures, which was repopulated latter with proliferative and less differentiated cells. Gene expression of ALP, OC, BSP, and BMP-7 was higher in LLLT treated cultures, while Runx2, OPN, and OPG were lower. These results indicate that LLLT modulates cell responses in a complex way stimulating osteoblastic differentiation, which suggests possible benefits on implant osseointegration despite a transient deleterious effect immediately after laser irradiation.

Effects of Low-Level Laser Therapy and Orthodontic Tooth Movement on Dental Pulps in Rats

To describe the microscopic pulpal reactions resulting from orthodontically induced tooth movement associated with low-level laser therapy (LLLT) in rats. Forty-five young male Wistar rats were randomly assigned to three groups. In group I (n = 20), the maxillary right first molars were submitted to orthodontic movement with placement of a coil spring. In group II (n = 20), the teeth were submitted to orthodontic movement plus LLLT at 4 seconds per point (buccal, palatal, and mesial) with a GaAlAs diode laser source (830 nm, 100 mW, 18 J/cm(2)). Group III (n = 5) served as a control (no orthodontic movement or LLLT). Groups I and II were divided into four subgroups according to the time elapsed between the start of tooth movement and sacrifice (12 hours, 24 hours, 3 days, and 7 days). Up until the 3-day period, the specimens in group I presented a thicker odontoblastic layer, no cell-free zone of Weil, pulp core with differentiated mesenchymal and defense cells, and a high concentration of blood vessels. In group II, at the 12- and 24-hour time points, the odontoblastic layer was disorganized and the cell-free zone of Weil was absent, presenting undifferentiated cells, intensive vascularization with congested capillaries, and scarce defense cells in the cell-rich zone. In groups I and II, pulpal responses to the stimuli were more intense in the area underneath the region of application of the force or force/laser. The orthodontic-induced tooth movement and LLLT association showed reversible hyperemia as a tissue response to the stimulus. LLLT leads to a faster repair of the pulpal tissue due to orthodontic movement.

Laser Light May Improve the Symptoms of Oral Lesions of Cicatricial Pemphigoid: A Case Report

The aim of this work is to report the handling of a patient suffering from cicatricial pemphigoid (CP) treated with laser phototherapy (LPT) and systemic steroids. CP is a group of rare chronic autoimmune blistering diseases that predominately affect the mucous membranes and occasionally the skin. The gingiva is most commonly involved, followed by the palate and the buccal mucosa. High-dosage systemic steroids are widely used for its treatment. LPT has been shown to improve wound healing and relieve pain. Its efficacy depends on the amount of energy delivered to the tissue, exposure time, and delivery method. A white 47-y-old man with CP who used systemic steroids for the previous 5 y was examined at our clinic. Extra- and intraoral examination revealed classic signs of the condition. LPT (GaAlAs diode laser, 660 nm wavelength, 30 mW, continuous wave, diameter approximately 3 mm, 60 J/cm(2) per session) was used in association with the steroids. LPT was performed in a punctual contact manner every other day on the oral mucosa. Maintenance of the treatment was carried out weekly because interruption of the LPT resulted in the recurrence of the lesions. At the time that this report was written, the patient had been undergoing twice weekly treatments for 6 months without signs of lesion recurrence. Concomitant use of systemic steroids and LPT showed a positive effect on controlling oral CP lesions and on improving both oral health and the quality of life of the patient.

A PROSPECTIVE STUDY OF THE INFLUENCE THAT TOPICAL STEROID EXERTS IN LOW REACTIVE LEVEL LASER THERAPY (LLLT) FOR THE TREATMENT OF HYPERTROPHIC SCARS AND KELOIDS.

The application of Low reactive Level Laser Therapy (LLLT) for the treatment of hypertrophic scars and keloids has been already reported and investigated. According to these reports, LLLT for hypertrophic scars and keloids was accepted very quickly into routine practice. In this prospective study, we assessed LLLT for the treatment of hypertrophic scars and keloids and examined the influence of a topical steroid. Subjects comprised 20 patients who were treated for hypertrophic scars and keloids, 9 patients treated with LLLT but no topical steroid and 11 patients treated with LLLT plus a topical steroid. Clinical photography of the lesions was performed, and 5 items were assessed for each lesion, namely Itching, Pain, Erythema, Hardness and Pliability on an 11-point scale for each value. The actual measurement values in mm and cm2 of 2 items (Thickness and size) were used. Each treatment session consisted of direct local application of an 830nm, 60mW, continuous wave, GaAlAs diode laser (Oh-lase 3D1, JMLL Tokyo Japan) to the target area for 30 seconds to 2 minutes per lesion depending on the size and number of lesions existing on each patient. The attending clinician firmly pinched the lesion between fingers and thumb during laser therapy. In both groups, a significant difference (p‹0.01) between pretreatment and the 5th or 10th treatment session was recognized in the Erythema, Hardness and Pliability items. In the Itching and Thickness items, a significant difference (p‹0.05) between pretreatment and the 5th or 10th treatment session was also recognized. There were no statistically significant differences between the group with no topical steroid and the group with topical steroid in most of the items, but the topical steroid group achieved better improvement in the Erythema and Hardness items after 10th treatment session, compared to the group with no topical steroid.

尿道下裂術後の尿道発毛に対する経尿道的レーザー脱毛

A 56-year-old male was admitted for induration of ventral side of the penile shaft. Computed tomography showed a large urethral calculus in the distal urethra. About 50 years previously, he had undergone multi-staged urethroplasty for hypospadias. He had also suffered from recurrent urethral calculi managed by urethrolithotomy 5 and 2 years before the admission. Urethrolithotomy revealed hair-bearing urethral calculus. Instillation of depilating agent containing thioglycolate into the neourethra for preventing hair regrowth was ineffective. Transurethral laser hair removal of neourethra was subsequently performed. All the neourethral follicles were ablated with GaAlAs diode laser (wave length 810 nm; at a power of 15W for 2 seconds) through a side-firing laser fiber. Another three operations were performed for a few regrown hairs at a power of 20-30W. Convalescence was uneventful. The patient is free of hair regrowth except for a hair at five months of follow-up.

THE EFFECT OF GaAlAs DIODE LASER ON PRE-SPORTS WARMING UP AND POST-SPORTS COOLING DOWN

Low reactive level laser therapy (LLLT) involving low incident levels of laser light, is known for its normalizing effect on abnormalities of living bodies. A joint study by Keio University Institute of Physical Education Japan Medical Laser Laboratory and the Ohshiro Clinic was conducted to investigate the application of the GaAlAs diode laser in the field of sports medicine during pre-training or pre-competition warm up and post-training cooling down. The ‘Sit and Reach’ test, blood oxygenation and pulse rates were measured in 17 athletes, 15 males and 2 females, before laser irradiation (A), after the first laser irradiation (B), after physical exertion (C) and after a second laser irradiation (D). The Oh-Lase HT 2001 semi-conductor laser was applied to the neck while the subject adopted a sitting position on the floor with the legs stretched forward. The subjects were requested to stretch (toe-touch) as far as possible followed by another 8 seconds of laser irradiation while the subjects were stretched and were measured for maximum stretching distance. The procedure was repeated. When statistical significance was evaluated there were significant changes between A and B, A and C, A and D, B and D, and C and D in the performance of the Sit and Reach Test, whereas significant differences in heart rate were seen between A and C, B and C, B and D, and C and D, and significant differences between A and B, A and D, B and C, and C and D in the blood oxygen saturation level. The results where significant differences between A and B, and C and D imply that the use of the GaAlAs laser during warm up and cool down is beneficial.

Effectiveness of Low-Level Laser Therapy in Temporomandibular Joint Disorders: A Placebo-Controlled Study

Low-level laser therapy (LLLT) treatment for pain caused by temporomandibular joint disorders (TMD) was investigated in a controlled study comparing applied energy density, subgroups of TMD, and duration of disorders. Although LLLT is a physical therapy used in the treatment of musculoskeletal disorders, there is little evidence for its effectiveness in the treatment of TMD. The study group of 61 patients was treated with 10 J/cm(2) or 15 J/cm(2), and the control group of 19 patients was treated with 0.1 J/cm(2). LLLT was performed by a GaAlAs diode laser with output of 400 mW emitting radiation wavelength of 830 nm in 10 sessions. The probe with aperture 0.2 cm(2) was placed over the painful muscle spots in the patients with myofascial pain. In patients with TMD arthralgia the probe was placed behind, in front of, and above the mandibular condyle, and into the meatus acusticus externus. Changes in pain were evaluated by self-administered questionnaire. Application of 10 J/cm(2) or 15 J/cm(2) was significantly more effective in reducing pain compared to placebo, but there were no significant differences between the energy densities used in the study group and between patients with myofascial pain and temporomandibular joint arthralgia. Results were marked in those with chronic pain. The results suggest that LLLT (application of 10 J/cm(2) and 15 J/cm(2)) can be considered as a useful method for the treatment of TMD-related pain, especially long lasting pain.

A phase III randomized double-blind placebo-controlled clinical trial to determine the efficacy of low level laser therapy for the prevention of oral mucositis in patients undergoing hematopoietic cell transplantation

Oral mucositis (OM) is a significant early complication of hematopoietic cell transplantation (HCT). This phase III randomized double-blind placebo-controlled study was designed to compare the ability of 2 different low level GaAlAs diode lasers (650 nm and 780 nm) to prevent oral mucositis in HCT patients conditioned with chemotherapy or chemoradiotherapy. Seventy patients were enrolled and randomized into 1 of 3 treatment groups: 650 nm laser, 780 nm laser or placebo. All active laser treatment patients received daily direct laser treatment to the lower labial mucosa, right and left buccal mucosa, lateral and ventral surfaces of the tongue, and floor of mouth with energy densities of 2 J/cm2. Study treatment began on the first day of conditioning and continued through day +2 post HCT. Mucositis and oral pain was measured on days 0, 4, 7, 11, 14, 18, and 21 post HCT. The 650 nm wavelength reduced the severity of oral mucositis and pain scores. Low level laser therapy was well-tolerated and no adverse events were noted. While these results are encouraging, further study is needed to truly establish the efficacy of this mucositis prevention strategy. Future research needs to determine the effects of modification of laser parameters (e.g., wavelength, fluence, repetition rate of energy delivery, etc.) on the effectiveness of LLE laser to prevent OM.

The effect of low-level laser therapy during orthodontic movement: a preliminary study

It has been emphasized that one of the most valuable treatment objectives in dental practice is to afford the patient a pain-free treatment. By the evolution of the laser applications, the dental committee aimed to achieve this goal without analgesic drugs and painful methods. Orthodontic treatment is one of these concerns, that one of the major components of patient to reject this treatment is the pain accompanied during the different treatment phases. Another great concern of the patient is not to get through prolonged periods of treatment. The aim of this study is to evaluate the effect of the low-level (GaAlAs) diode laser (809 nm, 100 mW) on the canine retraction during an orthodontic movement and to assess pain level during this treatment. A group of 15 adult patients with age ranging from 14 to 23 years attended the orthodontic department at Dental School, Damascus University. The treatment plan for these patients included extraction of the upper and lower first premolars because there was not enough space for a complete alignment or presence of biprotrusion. For each patient, this diagnosis was based on a standard orthodontic documentation with photographs, model casts, cephalometric, panorama, and superior premolar periapical radiographies. The orthodontic treatment was initiated 14 days after the premolar extraction with a standard 18 slot edgewise brackets [Rocky Mountain Company (RMO)]. The canine retraction was accomplished by using prefabricated Ricketts springs (RMO), in both upper and lower jaws. The right side of the upper and lower jaw was chosen to be irradiated with the laser, whereas the left side was considered the control without laser irradiation. The laser was applied with 0-, 3-, 7-, and 14-day intervals. The retraction spring was reactivated on day 21 for all sides. The amount of canine retraction was measured at this stage with a digital electronic caliper (Myoto, Japan) and compared each side of the relative jaw (i.e., upper left canine with upper right canine and lower left canine with lower right canine). The pain level was prompted by a patient questionnaire. The velocity of canine movement was significantly greater in the lased group than in the control group. The pain intensity was also at lower level in the lased group than in the control group throughout the retraction period. Our findings suggest that low-level laser therapy can highly accelerate tooth movement during orthodontic treatment and can also effectively reduce pain level.

Comparison of long term results after Ho:YAG and diode laser treatment of hyperplastic inferior nasal turbinates

Various laser systems have been used to reduce the volume of hyperplastic inferior nasal turbinates during the last 25 years. Although there are many studies reporting the clinical results immediately after laser treatment, there are only a few describing long-term results. Therefore, a clinical study was performed to assess and to compare the long-term outcome of both endonasal Ho:YAG and endonasal diode laser-assisted turbinate surgery. In the first treatment group, a total of 80 patients (allergic rhinitis (46%) and vasomotor rhinitis (54%)) suffering from nasal obstruction due to hyperplastic inferior nasal turbinates were treated by a pulsed Ho:YAG laser emitting light at a wavelength of lambda = 2,100 nm (pulse energy: 0.8-1.2 J/pulse, repetition rate: 4-8 Hz) under local anesthesia. In the second group, an additional 113 patients (allergic rhinitis (52%) and vasomotor rhinitis (48%)) were treated by means of a continuous wave GaAlAs-diode laser emitting light at a wavelength of lambda = 940 nm (power: 8-10 W). The treatment time was 3-10 minutes per turbinate and the nasal cavities were left unpacked following the procedure. The study concerning long-term effects was conducted using a standardized questionnaire, allergy test, and rhinomanometry within a follow-up period of 6 month and after 3 years. All patients were refractory to conservative medical treatment prior to laser treatment. Three years after laser treatment, a subjective improvement of nasal airflow had been described by the patients in 67.5% after Ho:YAG- and in 74.4% after diode laser treatment. Rhinomanometry revealed a significant improvement of the nasal airflow at both 6 months and 3 years after the laser treatment as compared to the preoperative data. Side effects like nasal dryness and pain were rare (<5%) and occurred only during the first weeks after the intervention. After diode laser treatment, patients showed nasal obstruction due to postoperative edema and nasal crusting during the first 3-4 weeks, whereas patients from the Ho:YAG laser group described these symptoms only for a period of 1-2 weeks. Both Ho:YAG- and diode laser treatment, which are performed as an outpatient procedure under local anesthesia, show promising long-term results. It has therefore, developed to become a time and cost-effective treatment modality in endonasal laser surgery at our institution. While short-term differences concerning the healing process after Ho:YAG- compared to diode-laser treatment could be ascertained according to the subjective and objective evaluation, no significant long-term differences between the two investigated groups could be observed.

LLLT FOR INTERSTITIAL CYSTITIS USING AN 830 NM GaAlAs DIODE LASER

Interstitial cystitis (IC) is a chronic inflammatory condition of the bladder wall, characterized by pelvic pain, urinary urgency, and frequency. Its etiology is unknown. IC remains a diagnosis of exclusion. Although there are no uniformly effective therapies, many treatment options are currently available. We present an IC patient who successfully underwent LLLT using an 830 nm GaAlAs diode laser. After 40 LLLT treatment sessions, the interstitial symptom index total score which was previously 19 decreased to 8 and the interstitial problem index total score which was previous 15 decreased to 6. Symptoms of severe bladder irritation and pelvic pain, urinary urgency and frequency improved almost completely for an extended period.

LOW REACTIVE-LEVEL LASER THERAPY IMPROVED SYSTEMIC SCLEROSIS-ASSOCIATED RAYNAUD’S PHENOMENON

Systemic sclerosis (SSC) is sometimes associated with the appearance of Raynaud’s disease due to diffuse vasculopathy associated with SSC. Low reactive-level laser therapy (LLLT) has been reported in the past to have beneficial effects in various vasculopathies, including Buerger’s and Raynaud’s diseases. The authors surmised that LLLT might therefore be of some assistance in the treatment of the Raynaud’s component of SSC. A 30-yr old male patient with SSC was treated with a combination of bosentan and LLLT (GaAlAs diode laser, 60 mW, continuous wave, incident power density 3 W/cm2) in 35 treatment sessions over 24 weeks. After the final treatment session, both skin tightness and Raynaud’s phenomenon had improved, whereas no progression was seen in the pulmonary fibrosis and pulmonary function did not get any worse. The results suggest that bosentan with complementary LLLT was effective for not only improving the dermal blood circulation but also preventing progression of the overall disease status in this case.

Arthralgia of the Temporomandibular Joint and Low-Level Laser Therapy

This case report describes the treatment of a patient with arthralgia of the temporomandibular joint (TMJ) caused by disc displacement. The goal of the treatment of TMJ arthralgia is to decrease pain by promotion of the musculoskeletal system's natural healing ability. This report describes the complex treatment of TMJ arthralgia. Low-level laser therapy (LLLT) was chosen for its antiinflammatory 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 intraarticular 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. 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 degrees C. However, at the conclusion of LLLT, temperatures in the areas surrounding the TMJ were equalized. 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.

Effect of Er:YAG and Diode lasers on the adhesion of blood components and on the morphology of irradiated root surfaces

The aim of this study was to evaluate in vitro, by scanning electron microscopy (SEM), the adhesion of blood components on root surfaces irradiated with Er:YAG (2.94 microm) and GaAlAs Diode (808 nm) lasers and the effects on the morphology of irradiated root surfaces. One hundred samples of human teeth were obtained. They were previously planed and scaled with manual instruments and divided into five groups of 20 samples each: G1 (control group) - absence of treatment; G2--Er:YAG laser (7.6 J/cm2); G3--Er:YAG laser (12.9 J/cm2); G4--Diode laser (90 J/cm2) and G5--Diode laser (108 J/cm2). After these treatments, 10 samples of each group received a blood tissue but the remaining 10 did not. After laboratory treatments, the samples were obtained by SEM, the photomicrographs were analysed by the score of adhesion of blood components and the results were statistically analysed (Kruskall-Wallis and Mann-Whitney test). In relation to the adhesion of blood components, the study showed no significant differences between the control group and the groups treated with Er:YAG laser (p = 0.9633 and 0.6229). Diode laser radiation was less effective than control group and Er:YAG laser radiation (p < 0.01). None of the proposed treatments increased the adhesion of blood components in a significant way when compared to the control group. Although the Er:YAG laser did not interfere in the adhesion of blood components, it caused more changes on the root surface, whereas the Diode laser inhibited the adhesion.

Laser heterodyne optovoltaic effect in the microwave range

Dynamic characteristics of the optovoltaic effect in the mega-and gigahertz range have been studied by detecting longitudinal modes of a semiconductor injection laser diode with a tunable external resonator. The electron lifetime in the active region of the p-n junction was determined by measuring the amplitude of the alternating injection current component at an intermode beat frequency in the course of resonator length tuning. As the resonator length was varied from 1 m to 3 cm, the beat frequency changed from 150 MHz to 5 GHz. In this case, the characteristic range of the optovoltaic effect in GaAlAs laser diodes (λ = 0.82 μm) is limited by the spontaneous electron recombination time, which is on the order of 0.8 ns. An electron-photon noise resonance has been observed in the coherent radiation and in the injection current.

Influence of different power densities of LILT on cultured human fibroblast growth

The aim of this in vitro study was to analyze the influence of different power densities of low-intensity laser therapy (LILT) on the biomodulation of human gingival fibroblasts. The cells were cultured in nutritional deficit. Laser irradiation was carried out with a GaAlAs diode laser (lambda-660 nm, 2 J/cm2). The irradiation was done twice with 12-h interval using the punctual technique, at continuous mode and in contact. The experimental groups were: I, control, nonirradiated; II, power of 10 mW and intensity approximately or equal to 142.85 mW/cm2; III, 29 mW and 428.57 mW/cm2. Growth curves were obtained by using the trypan blue dye exclusion assay. The cell growth of the irradiated groups was significantly higher than control group (P<or=0.05). The cultures of Group II presented cell growth superior to that of Group III. Based on the conditions of this study, we concluded that the power density influences cell growth in an inversely proportional manner.

Lethal photosensitization and guided bone regeneration in treatment of peri‐implantitis: an experimental study in dogs

The purpose of this study was to evaluate the effect of lethal photosensitization and guided bone regeneration (GBR) on the treatment of ligature-induced peri-implantitis in different implant surfaces. The treatment outcome was evaluated by clinical and histometric methods. A total of 40 dental implants with four different surface coatings (10 commercially pure titanium surface (cpTi); 10 titanium plasma-sprayed (TPS); 10 acid-etched surface; 10 surface-oxide sandblasted) were inserted into five mongrel dogs. After 3 months, the animals with ligature-induced peri-implantitis were subjected to surgical treatment using a split-mouth design. The controls were treated by debridment and GBR, while the test side received an additional therapy with photosensitization, using a GaAlAs diode laser, with a wavelength of 830 nm and a power output of 50 mW for 80 s (4 J/cm2), and sensitized toluidine blue O (100 microg/ml). The animals were sacrificed 5 months after therapy. The control sites presented an earlier exposition of the membranes on all coating surfaces, while the test group presented a higher bone height gain. Re-osseointegration ranged between 41.9% for the cpTi surface and 31.19% for the TPS surface in the test sites; however differences were not achieved between the surfaces. The lethal photosensitization associated with GBR allowed for better re-osseointegration at the area adjacent to the peri-implant defect regardless of the implant surface.