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OBJECTIVE: To explore the feasibility of the usage of digital guides in combination with low- and high-power lasers for the treatment of excessive gingival display, also known as "gummy smile". CLINICAL CONSIDERATIONS: Excessive gingival display due to altered passive eruption can affect patient's perception of their own esthetics and consequently have an impact on self-confidence. Therefore, the management of this condition should offer a predictable and stable long-lasting solution. To attain these objectives, digital planning emerges as a tool in optimizing the outcomes of crown lengthening surgery for this condition by enhancing precision through the use of surgical guides. Additionally, the usage of high- and low-powered lasers can provide a safe approach because of their tissue selective removal properties. CONCLUSIONS: The technique described showed satisfactory clinical results in the short- and long-term follow-up, leading to an improvement in patients' self-esteem. This approach integrates digital and laser technologies to deliver a surgical treatment characterized by precision, efficiency, and safety. CLINICAL SIGNIFICANCE: Digital dentistry has contributed to innovative dental procedures, as personalizing surgical guides for patients, assisting and guiding incisions of the gingival margins, as well as the extension of the osteotomy, during the procedures for increasing the clinical crown. Furthermore, smile esthetics are directly related to an individual's improved emotional and social quality of life.

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Introduction: Osteoradionecrosis (ORN) is a secondary complication from radiotherapy, which is difficult to manage and significantly reduces the life quality of the affected patients. Case Report: A 59-year-old female patient, diagnosed with infiltration by squamous cell carcinoma in the left cervical region, underwent adjuvant cervical-facial radiotherapy with a total dose of 66.6 Gy of radiation. Eight years after the diagnosis, the patient underwent multiple extractions and, subsequently, the installation of osseointegrated implants, evolving to extensive intraoral bone exposure associated with oral cutaneous fistula. The patient was initially exposed to photobiomodulation therapy (PBMT), with a low-power laser at wavelengths of 660 nm and 808 nm, and thereafter to antimicrobial photodynamic therapy (aPDT). After an improvement in the clinical condition and resolution of the oral cutaneous fistula, a surgical procedure with the Er: YAG laser was performed to remove the remaining necrotic bone. Once the ORN condition was completely treated, the patient's oral rehabilitation was implemented by the installation of an upper mucous-supported total prosthesis and a lower implant-supported prosthesis. Conclusion: The patient is in a clinical follow-up and has no signs of bone necrosis recurrence, suggesting that low and high-power laser treatment can be an effective therapeutic alternative to resolve this condition.

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The objective of this study was to describe the histological artifacts caused by high-power laser use compared to cold scalpel surgery in oral soft tissue lesions. Clinical studies that evaluated and compared histological artifacts resulting from the use of high-power lasers and cold scalpels in oral soft tissue lesions biopsies were retrieved from seven databases and four grey literatures, up to July 2022. The risk of bias was investigated using the ROBINS-I tool. The certainty of the evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Seven studies were eligible for qualitative analysis. Based on the results obtained, those four studies had a low risk of bias, and three studies had an unclear risk of bias. The certainty of the evidence was classified as low. Limited evidence showed that epithelial artifacts such as loss of intraepithelial and subepithelial adhesions, accompanied by pyknotic, fusiform, and/or hyperchromic nuclei, were more common when a high-power laser device was used. Four articles reported that the use of high-power lasers did not interfere with the histopathological diagnosis of oral soft tissue lesions. Due to the heterogeneity of the data, a meta-analysis was not performed. Compared to the use of cold scalpels, histological artifacts, particularly those observed in epithelial tissue, are more common when high-powered lasers are used in oral lesions biopsies. The eligibility criteria and adequate indications of high-power lasers in different oral soft tissue lesion treatments must be respected to avoid tissue artifacts that impair precise histopathological diagnosis.

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The aim of the present study was to analyze for the first time the effect of photobiomodulation therapy (PBMT) using defocused high-power laser (DHPL) in myoblast cell line C2C12 viability and migration and compare them with low-power laser therapy. Cells were divided into 9 groups: Sham irradiation 10% fetal bovine serum (FBS); Sham irradiation 5%FBS; low-power laser 0.1 W; DHPL 810 1 W; DHPL 810 2 W; DHPL 980 1 W; DHPL 980 2 W; DHPL dual 1 W; DHPL dual 2 W. To simulate stress conditions, all groups exposed to irradiation were maintained in DMEM 5% FBS. The impact of therapies on cell viability was assessed through sulforhodamine B assay and on cells migration through scratch assays and time-lapse. Myoblast viability was not modified by PBMT protocols. All PBMT protocols were able to accelerate the scratch closure after 6 and 18 h of the first irradiation (p < 0.001). Also, an increase in migration speed, with a more pronounced effect of DHPL laser using dual-wavelength protocol with 2 W was observed (p < 0.001). In conclusion, the diverse PBMT protocols used in this study accelerated the C2C12 myoblasts migration, with 2-W dual-wavelength outstanding as the most effective protocol tested. Benefits from treating muscle injuries with PBMT appear to be related to its capacity to induce cell migration without notable impact on cell viability.

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Skin wounds represent a burden in healthcare. Our aim was to investigate for the first time the effects of defocused high-power diode laser (DHPL) on skin healing in an animal experimental model and compare it with gold standard low-level laser therapy. Male Wistar rats were divided into 5 groups: Negative control; Sham; 0.1 W laser (L0.1 W); DHPL Dual 1 W (DHPLD1 W); and DHPL Dual 2 W (DHPLD2 W). Rats were euthanized on days 3, 5, 10, 14 and 21. Clinical, morphological, PicroSirus, oxidative stress (MDA, SOD and GSH) and cytokines (IL-1ß, IL-10 and TNF-α) analyses were performed. A faster clinical repair was observed in all laser groups at D10 and D14. DHPLD1 W exhibited lower inflammation and better reepithelization compared to other groups at D10. DHPL protocols modulated oxidative stress by decreasing MDA and increasing SOD and GSH. Collagen maturation was triggered by all protocols tested and L0.1 W modulated cytokines release (IL-1ß and TNF-α) at D3. In conclusion, DHPL, especially DHPL1 W protocol, accelerated skin healing by triggering reepithelization and collagen maturation and modulating inflammation and oxidative stress.

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Introduction: The use of low-level laser therapy to treat wounds and accelerate tissue healing has extensively been studied in recent years. The aim of this article is to describe a clinical case using an unfocused high-power laser instead of a low-power laser for therapy. Case Report: In the present article, we present the use of a high-power diode laser to treat an extensive knee injury that occurred after surgical treatment for total prosthesis due to border ischemia resulting from prolonged use of autostatic retractors. Conclusion: It is possible to use an unfocused high-power laser at a decreased intensity to accelerate healing as an adjuvant in the treatment of complicated wounds. This procedure results in reduced application time and cost and an excellent tissue response pattern similar to that reported in the literature with low-power lasers.

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The aim of this triple-blind randomized clinical trial was to evaluate the efficacy and safety of diode laser during circumvestibular incisions for Le Fort I osteotomy in orthognathic surgeries in comparison with conventional techniques using electrocautery and scalpel. Patients were randomly allocated to one of three groups based on the technique employed to perform incisions: diode laser, electrocautery, and scalpel. The parameters used to evaluate the efficacy and safety of diode laser were incision velocity, duration of surgery, bleeding rate, alterations in postoperative functions, pain, edema, wound clinical healing, and infection. Thirty patients were enrolled in the study (10 per group). Regarding bleeding, the incisions performed with diode laser promoted a lower bleeding rate compared with scalpel and electrocautery (p = 0.00). The diode surgical laser was effective during the incision procedure, but required a longer time to perform the incisions compared with the other techniques evaluated (p < 0.05). No statistically significant difference was detected between groups regarding total surgical time or other safety parameters (p > 0.05). Thus, diode laser proved to be effective and safer during circumvestibular incisions for Le Fort I osteotomy than conventional devices.

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BACKGROUND: Drug-induced gingival overgrowth (DIGO) is attributed mainly to the prolonged use of calcium channel blocking agents, anticonvulsants, and anti-calcineurin inhibitors . The management of DIGO depends on the severity of the disease and includes surgical intervention and plaque control. Compared to conventional surgical treatment, the recent literature data have shown that gingivectomy using a high-power laser (HPL) is a short and easy procedure, which results in minimal postoperative discomfort and greater patient accep- tance. OBJECTIVE AND METHODS: The purpose of this study was to report two cases of recurrent DIGO treated surgically using HPL (λ 808nm, 1.5W). RESULTS: Minimal bleeding and discomfort were observed during surgery, and patients reported no pain or bleeding after the procedure. After 1 year of follow-up, patients presented a minimal increase of gingival volume, indicating that laser technology can improve the efficiency and prognosis of DIGO. CONCLUSIONS: The HPL was able to preventing hemorrhage and improving the patient's collaboration with the treatment and quality of life.

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The incisions during orthognathic surgery are classically performed with conventional scalpel or electrocautery. Considering that the high-power diode laser surgery may provide advantages when compared to conventional incision techniques, the current study aimed to present a prospective case series of patients submitted to circumvestibular incision for Le Fort I osteotomy. Ten patients with dentofacial deformities who underwent to rapid assisted maxillary expansion or bimaxillary orthognathic surgery were enrolled in the study. All incisions were performed by a single surgeon using an 808-nm diode laser, with an optical fiber of 600 µm, at a power of 2.5 W, in a continuous-wave mode. The performance of the incision was evaluated by incision velocity, bleeding, edema, secondary infection, clinical healing, and pain. The velocity of the incision ranged from 0.10 to 0.20 mm/s (mean 0.13 ± 0.03 mm/s). Considering bleeding during the soft tissue incision, all surgeries were classified as absent bleeding. All patients presented a clinical healing of the surgical wound in a period that range from 3 to 5 weeks and experienced swelling during the follow-up period. On average, approximately 50% of the swelling had resolved after the third postoperative week, and 28.8% of swelling remained after 2 months after the surgery. The pain decreased after 2 and 3 days, and 90.0% of the patients reported no pain after 7 postoperative days. High-power diode laser is effective and safety during circumvestibular incisions for Le Fort I osteotomy in orthognathic surgery decreasing bleeding, surgery time, pain, and edema after orthognathic surgery.

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BACKGROUND: High power lasers have been suggested as a useful tool for dental caries and erosion prevention due to the increase of enamel acid resistance. OBJECTIVE: to evaluate the effect of Er,Cr:YSGG (erbium,chromium:yttrium, scandium, gallium, garnet) laser irradiation pulse frequency and power on enamel surface and acid erosion resistance. METHODS: By combining pulse frequency (5-75 Hz) and power settings (0.10-1.00 W), 20 irradiated groups and one nonirradiated control group were tested. A total of 63 bovine enamel blocks (n = 3/group) were prepared for surface hardness and roughness evaluation, performed in three phases: baseline, after irradiation, and after erosive challenge. Enamel blocks were irradiated with Er,Cr:YSGG laser with MZ8 tip (iPlus; Waterlase, Biolase, CA) for 30 sec according to experimental group and submitted. Erosive challenge consisted of four cycles alternating immersion in 0.01 M HCl (5 mL/mm2; 2 min; at 37°C) and immersion in artificial saliva for 3 h. Analysis of variance (three-way ANOVA), Tukey's test, and Pearson correlation were performed for the statistical analysis (p < 0.05). RESULTS: After irradiation, groups irradiated with pulse frequency of 10 and 15 Hz showed a decrease in surface hardness. After erosive challenge, 5 and 75 W groups showed increase in surface hardness; 0.25, 0.5, 0.75, and 1 W groups showed minor alterations in surface roughness. CONCLUSIONS: the irradiation of Er,Cr:YSGG laser with different parameters of power and pulse frequency settings may alter enamel surface and erosive resistance differently. Pulse frequency of 30 Hz and power of 0.50 W was considered the best parameter to prevent enamel acid erosion.

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BACKGROUND AND OBJECTIVES: The most common injury to the heart valve with rheumatic involvement is mitral stenosis, which is the reason for a big number of cardiac operations in Brazil. Commissurotomy is the traditional technique that is still widely used for this condition, although late postoperative restenosis is concerning. This study's purpose was to compare the histological findings of porcine cusp mitral valves treated in vitro with commissurotomy with a scalpel blade to those treated with high-power laser (HPL) cutting, using appropriate staining techniques. MATERIALS AND METHODS: Five mitral valves from healthy swine were randomly divided into two groups: Cusp group (G1), cut with a scalpel blade (n = 5), and Cusp group (G2), cut with a laser (n = 5). G2 cusps were treated using a diode laser (λ = 980 nm, power = 9.0 W, time = 12 sec, irradiance = 5625 W/cm2, and energy = 108 J). RESULTS: In G1, no histological change was observed in tissue. A hyaline basophilic aspect was focally observed in G2, along with a dark red color on the edges and areas of lower birefringence, when stained with hematoxylin-eosin, Masson's trichrome, and Sirius red. Further, the mean distances from the cutting edge in cusps submitted to laser application and stained with Masson's trichrome and Sirius red were 416.7 and 778.6 µm, respectively, never overcoming 1 mm in length. CONCLUSIONS: Thermal changes were unique in the group submitted to HPL and not observed in the cusp group cut with a scalpel blade. The mean distance of the cusps' collagen injury from the cutting edge was less than 1 mm with laser treatment. Additional studies are needed to establish the histological evolution of the laser cutting and to answer whether laser cutting may avoid valvular restenosis better than blade cutting.

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O objetivo deste estudo foi avaliar através de um ensaio clínico randomizado, a eficácia e segurança do laser cirúrgico de diodo durante as incisões circunvestibulares para osteotomia Le Fort I. Os pacientes foram divididos aleatoriamente em 3 grupos: incisão feita com bisturi, com eletrocautério ou a laser cirúrgico de diodo com comprimento de onda de 808nm. Os parâmetros clínicos utilizados para avaliar a eficácia e segurança dos diferentes métodos de incisão foram: velocidade de incisão, tempo cirúrgico total, sangramento transoperatório, alterações funcionais de fala e alimentação, dor e edema pós-operatório, tempo de cicatrização das feridas e taxas de infecção. Foram incluídos 30 pacientes no estudo, 10 em cada grupo. O laser cirúrgico de diodo foi eficaz durante o corte, porém levou maior tempo para a realização das incisões quando comparado às técnicas convencionais (p=0,00). Em contrapartida, não foi encontrada diferença estatisticamente significativa entre os grupos em relação ao tempo cirúrgico total (p=0,88). Em relação ao sangramento, as incisões realizadas com o laser cirúrgico promoveram menor sangramento quando comparadas ao bisturi e eletrocautério (p=0,00). Não foram encontradas associações estatisticamente significativas entre os grupos em relação aos outros parâmetros clínicos estudados. Conclui-se que o laser cirúrgico de diodo provou ser eficaz e seguro durante as incisões circunvestibulares para osteotomia Le Fort I.(AU)

The aim of this study was to evaluate through a randomized clinical trial the efficacy and safety of diode laser during the circumvestibular incision for the Le Fort I osteotomy. Patients were randomly allocated in one of three groups based on the technique employed to perform incisions: scalpel, electrocautery or 808nm high-power diode laser. Clinical parameters were used to evaluate the efficacy and safety of the diode laser: incision velocity, duration of the surgery, bleeding, postoperative functions alterations (eating and speech), pain, oedema, wound clinical healing and secondary infection. Thirty patients were enrolled in the study, 10 in each group. The diode surgical laser was effective during cut, but was slower to perform the incisions when compared to conventional techniques (p<0.05). However, no statistically difference was found between the groups in relation to the total surgical time (p>0.05). Regarding bleeding, the incisions performed with diode laser promoted lower bleeding rate in comparison to the scalpel and electrocautery (p=0.00). No statistically significant associations were found between the groups in relation to other clinical parameters studied. In conclusion, the diode laser is effective and safe during the circumvestibular incision for Le Fort I osteotomy.(AU)

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Worldwide, rheumatic fever remains a significant cause of mitral valve insufficiency. It is responsible for approximately 90 % of early childhood valvular surgeries in Brazil. Elongated or flail chordae are frequently responsible and require surgical correction. The purpose of this study was to analyze and compare the histological tissues of the mitral valve chordae and the mechanical resistance generated by the chordae, both with and without the application of a high-power laser. Twenty normal porcine mitral valve chordae were measured and divided randomly into the following two groups: control group (not subjected to a high-power laser) and laser group (subjected to photonic irradiation). Laser surgery was performed under controlled conditions, using following parameters: λ = 980-nm wavelength, power = 3 W, and energy = 60 J. A mechanical test machine was used in combination with a subsequent histological study to measure chordae tensile properties. A histological analysis demonstrated a typical collagen bundle arrangement in the control group; however, under a particular reached temperature range (48), the collagen bundles assumed different arrangements in the laser group. Significant reductions in the chordae tendineae lengths and changes in their resistance in the laser group were observed, as these chordae exhibited less rigid fibers. The chordae tendineae of normal porcine valves subjected to a high-power laser exhibited its length reduction and less stiffness compared to the control group. A histological analysis of the laser treatment specimens demonstrated differences in collagen bundle spatial organization, following slight changes into tissue temperature.

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