The effect of low-level diode laser on COX-2 gene expression in chronic periodontitis patients

Adjunctive treatments to scaling and root planing (SRP) such as lasers, have been utilized in the treatment of chronic periodontitis, mainly aiming to suppress and eliminate the bacteria, as well as enhancing the healing response. Eighty gingival papilla biopsy samples were obtained from 60 patients diagnosed with chronic advanced periodontitis; randomly assigned to three treatment groups (n = 20), as well as 20 subjects with no periodontal disease [group A]. Group B received SRP on a single quadrant/day for four consecutive days. On day 5, all quadrants were rescaled. Groups C and D received the same treatment as group B plus laser application with the low-level diode laser (630-670 nm, 1.875 J/cm2) for five and ten consecutive days, respectively. Papilla biopsies were obtained from subjects and evaluated by RT-PCR for expression of COX-2. The values in the control group were 0.028 0.014 and baseline values for the examined groups were 0.16 0.18. Significantly decreased level of COX-2 expression for groups C and D was found after treatment, while lowest average expression was found in the group that had the 10 laser treatments supplemental to SRP (0,035 0,014). The results of this study show suppression of COX-2 in gingival tissue after low-level laser treatment as adjunct to SRP.     

Effect of lipoteichoic acid on proliferation and differentiation of keratinocytes

Bacterial infection is always found to be associated with cholesteatoma. Accumulation of keratin debris is one of the crucial factors for the growth of cholesteatoma. The effects of lipoteichoic acid, a cell wall component of gram-positive bacteria, on the proliferation and differentiation of keratinocytes were studied. Various concentrations of lipoteichoic acid (0 to 100 micrograms/ml) were added to keratinocytes. DNA synthesis and protein synthesis were inhibited by decreasing the incorporation of 3H-thymidine and 3H-leucine into keratinocytes. The effects of lipoteichoic acid on terminal differentiation were then studied by measuring the number of sodium dodecyl sulfate-insoluble cornified cell envelopes and the transglutaminase activity (a marker of terminal differentiation) determined by incorporation of 3H-putrescine into cornified envelopes. These studies showed that lipoteichoic acid stimulated the formation of cornified cell envelopes and transglutaminase activity. These findings suggest that lipoteichoic acid stimulated the terminal differentiation and accumulation of keratin debris and that lipoteichoic acid might have stimulatory effects on the development of cholesteatoma.     

Effect of a diode laser on wound healing by using diabetic and nondiabetic mice

The purpose of this study was to evaluate a 980-nm gallium-aluminum-arsenide diode laser for wound healing. Using genetically diabetic and nondiabetic mice, two 6-mm wounds were created on the back of each mouse by using a punch biopsy. The mice were assigned to 1 of 4 subgroups for laser treatment at different fluence and frequency of treatment: 5 W (18 J/cm2) every 2 days, 5 W (18 J/cm2) every 4 days, 10 W (36 J/cm2) every 2 days, and 10 W (36 J/cm2) every 4 days. In addition, control mice were used and the wounds were allowed to heal naturally. Wound healing was evaluated on days 5, 12, and 19 by percentage of wounds healed and percent wound closure. A maximum of 5 mice per subgroup were killed at days 7, 14, and 21, and histology was conducted on the wound sites. For diabetic mice receiving 5 W every 2 days, the percentage of wounds healed after 19 days was 100% versus 40% in the control group. Only 20% of wounds in the 10-W diabetic subgroups achieved healing during the same period. For the subgroups whose wounds did not completely heal, all but the 10 W every 2 days subgroup had average closure of >90%. The 100% closure for the 5 W every 2 days subgroup was significantly greater than the other subgroups. For nondiabetic mice, 100% of the wounds in the 5 W every 4 days and control subgroups were completely healed, whereas 90% of the wounds from the 5 W every 2 days and the 10 W every 4 days subgroups were completely healed. In the latter 2 subgroups, wound closure was 99.4% and 98.8%, respectively. These differences were not significant. The histologic results confirmed these findings. In conclusion, treatment at 18 J/cm2 shows a beneficial effect on wound healing in diabetic mice and does not have a detrimental effect in nondiabetic mice.     

Morphologic changes and removal of debris on apical dentin surfaces after Nd:YAG laser and diode laser irradiation

OBJECTIVE: To verify the effects of laser energy on intracanal dentin surfaces, by analyzing the morphologic changes and removal of debris in the apical third of 30 extracted human teeth, prepared and irradiated with the Nd:YAG laser and diode laser. BACKGROUND DATA: Lasers have been widely used in endodontics. The morphologic changes in dentin walls caused by Nd:YAG and diode laser irradiation could improve apical seals and cleanliness. MATERIALS AND METHODS: The protocol used for Nd:YAG laser irradiation was 1.5 W, 100 mJ, and 15 Hz, in pulsed mode, and for diode laser was 2.5 W in continuous mode. Each specimen was irradiated four times at a speed of 2 mm/sec with a 20-sec interval between applications. Five calibrated examiners scored the morphologic changes and debris removal on a 4-point scale. RESULTS: In analyzing the scores, there were no statistically significant differences between the two types of laser for either parameter, according to Kruskal-Wallis testing at p = 0.05. The SEM images showed fusion and resolidification of the dentin surface, with partial removal of debris on the specimens irradiated with the Nd:YAG laser and the diode laser, compared with controls. CONCLUSION: Both lasers promote morphologic changes and debris removal. These alterations of the dentin surface appeared to be more evident in the Nd:YAG laser group, but the diode laser group showed more uniform changes.     

Study on pathogenesis of Enterococcus faecalis in urinary tract

Summary The rate of isolation of Enterococcus faecalis as the causative bacterium of complicated urinary tract infections has been increasing. However, the pathogenicity of this bacterium in the urinary tract has not been clarified. Thus, the authors investigated how E. faecalis is pathogenic to the urinary tract, using mice with experimental urinary tract infection. The investigation revealed that this bacterium when sufficiently numerous can be directly pathogenic. The bacterium can be pathogenic indirectly when present with other typical urinary bacteria such as E. coli.     

Effectiveness of corneal neovascularization photothrombosis using phthalocyanine and a diode laser (675 nm)

We used chloroaluminum sulfonated phthalocyanine as a photosensitizer and a diode laser as a light source for induction of photothrombosis of corneal neovascularization. Corneal neovascularization was induced in 1 eye of each of 10 New Zealand white rabbits using intrastromal 6.0 silk sutures. After the intravenous injection of phthalocyanine in a dose of 4 mg per kg of body weight, photothrombosis was carried out using a diode laser emitting at 675 nm. The animals were followed up by both fluorescein angiography and slit-lamp photography for up to three months. At the end of the follow-up period the eyes were prepared for histology. After photothrombosis, thrombus formation was induced within new vessels demonstrating histological characteristics of both arterioles and venules. Most of the vessels disappeared or remained closed during the follow-up period. Recanalization of some of the thrombosed vessels occurred within the first 20 days after the operation. The combination of phthalocyanine and a 675 nm diode laser is effective for the induction of photothrombosis of corneal neovascularization. © 1993 Wiley-Liss, Inc. © 1993 Wiley-Liss, Inc.     

Effects of pulse width on erbium: YAG laser photothermal trabecular ablation (LTA)

An erbium (Er):YAG laser can remove trabecular meshwork (TM) by photothermal ablation with minimal contiguous thermal damage. A variable pulse width Er:YAG laser was used to investigate the effect of varying pulse width on ablation of human TM. Trabecular photothermal ablation was performed on tissue obtained from eye bank eyes at pulse widths of 50, 150, and 250μs, with energy held constant at 4 mJ. At this energy, a single laser pulse was sufficient for full-thickness ablation of TM. Laser energy was delivered through a 200-μm diameter optical fiber held in apposition to the tissue sample, which was immersed in physiologic saline. High-speed photography of the resultant steam bubbles also was performed. Light microscopy and scanning electron microscopy of TM ablated at 50 μs revealed the greatest variability in size (0–140 μm) of the full-thickness ablated areas and demonstrated blast effects, tissue shredding and ?10 μm thermal damage. At 150 μs, the full-thickness ablated areas were more consistent in size (115–120 μm), showed no blast effects and 10 to 20 μm thermal damage. At 250 μs, the largest ablations were found (180–220 μm) and showed no blast damage; however, a significant amount of thermal damage (?50 μm) was evident. The steam bubbles produced by the laser energy were largest at 50 μs and did not begin to collapse until well over twice the original pulse interval. At 150 and 250 μs, the steam bubbles were successively smaller and dissipated at the end of the laser pulse. In single pulse Er:YAG photothermal laser trabecular ablation, a pulse width (total energy of 4 mJ) around 150 μs appears to be optimal. The resultant acoustic shock wave from steam bubble formation is smaller, its duration does not exceed the laser pulse width and tissue thermal damage is minimal. © 1993 Wiley-Liss, Inc.     

Effectiveness of diode laser as adjunctive therapy to scaling root planning in the treatment of chronic periodontitis: a meta-analysis

To investigate whether the adjunctive use of diode laser provides additional benefits to scaling root planning alone in patients with chronic periodontitis, a meta-analysis was conducted according to the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement and the Cochrane Collaboration. A literature search was performed on seven databases, followed by a manual search. Weighted mean differences and 95 % confidence intervals were calculated for the clinical attachment level, probing depth, and changes in the plaque and gingival indices. The I ² test was used for interstudy heterogeneity. Visual asymmetry inspection of the funnel plot, Egger’s regression test, and the trim-and-fill method were used to investigate publication bias. All outcomes were evaluated at 6 months. No significant differences were observed for any investigated outcome of interest. No evidence of heterogeneity or publication bias was detected. These findings suggested that the use of diode laser as an adjunctive therapy to conventional nonsurgical periodontal therapy did not provide additional clinical benefit. However, given that few studies were included in the analysis, and that three of the five included studies had a high risk of bias, the results should be interpreted with caution. Important issues that remain to be clarified include the influence of smoking on clinical outcomes, the effectiveness of adjunctive diode laser on microbiological outcomes, and the occurrence of adverse events. Future long-term well-designed parallel randomized clinical trials are required to assess the effectiveness of the adjunctive use of diode laser, as well as the appropriate dosimetry and laser settings.     

Clinical and biochemical effects of diode laser as an adjunct to nonsurgical treatment of chronic periodontitis: a randomized, controlled clinical trial

The aim of this randomized, parallel, controlled clinical trial was to examine the clinical and biochemical efficacy of diode laser as an adjunct to scaling and root planing (SRP). Thirty chronic periodontitis patients were randomly assigned into two groups to receive SRP alone (control) or SRP followed by diode laser (test). Plaque index, gingival index, bleeding on probing, probing depth, and clinical attachment level were measured at baseline and at 1, 3, and 6 months after treatment. The gingival crevicular fluid levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), matrix metalloproteinase-1 (MMP-1), matrix metalloproteinase-8 (MMP-8) and tissue inhibitor matrix metalloproteinase-1 (TIMP-1) were analyzed by enzyme-linked immunosorbent assay. Test group showed significantly a better outcome compared to the control group in full-mouth clinical parameters. MMP-1, MMP-8, and TIMP-1 showed significant differences between groups after treatment compared to baseline (p?<?0.05). The total amount of IL-1β, IL-6, MMP-1, MMP-8, and TIMP-1 decreased (p?<?0.05) and IL-8 increased after treatment in both test and control groups (p?<?0.05). Diode laser provided significant improvements in clinical parameters and MMP-8 was significantly impacted by the adjunctive laser treatment at first month providing an insight to how lasers can enhance the outcomes of the nonsurgical periodontal therapy.     

Effect of 655-nm diode laser on dog sperm motility

Sperm motility depends on energy consumption. Low-level laser irradiation increases adenosin triphosphate (ATP) production and energy supply to the cell. The aim of this study is to analyse whether the irradiation affects the parameters that characterise dog sperm motility. Fresh dog sperm samples were divided into four groups and irradiated with a 655-nm continuous-wave diode laser with varying doses: 0 (control), 4, 6 and 10 J/cm². At 0, 15 and 45 min following irradiation, pictures were taken of all the groups in order to study motility with computer-aided sperm analysis (CASA). Functional tests were also performed. Average path velocity (VAP), linear coefficient (Lin) and beat cross frequency (BCF) were statistically and significantly different when compared to the control. The functional tests also showed a significant difference. At these parameters, the 655-nm continuous-wave diode laser improves the speed and linear coefficient of the sperm.     

The effects of a diode laser (810 nm) on pigmented guinea-pig skin

Various types of lasers, such as the Q-switched ruby laser and the Alexandrite laser, cause selective damage to cutaneous pigmented cells and are currently used in the therapy of pigmented lesions. The aim of this study was to evaluate the effects of a diode laser at a wavelength of 810 nm on pigmented guinea-pig skin. The diode laser was supplied by OcuLight Iris Medical Instruments, Inc. and was used to deliver 0.15, 0.2, 0.3, 0.4, 0.5, 1 and 1.5 J/cm² laser beams in micropulses of 100 μs. The study was carried out on albino and black-spotted guinea pigs (GP). After irradiation, punch biopsies were taken and analysed by light and electron microscopy. Albino animals developed just a few signs of cutaneous injury. This mostly consisted of spongiotic disarray, after the highest doses were administered (>1 J/cm²). In the black skin of spotted GPs alterations appeared at 0.15 J/cm² and included melanosome damage and, at doses higher than 0.3 J/cm², also melanocyte damage. These observations demonstrate that the diode laser at 810 nm selectively affects pigmented structures and that the cellular targets of diode laser radiation are the melanosomes. The diode laser specificity for melanin may provide a biological basis for the treatment of pigmented superficial cutaneous lesions. Paper received 15 December 1999; accepted 5 October 2000.     

Effect of 830-nm diode laser irradiation on human sperm motility

Sperm motility is known as an effective parameter in male fertility, and it depends on energy consumption. Low-level laser irradiation could increase energy supply to the cell by producing adenosine triphosphate. The purpose of this study is to evaluate how the low-level laser irradiation affects the human sperm motility. Fresh human semen specimens of asthenospermic patients were divided into four equal portions and irradiated by 830-nm GaAlAs laser irradiation with varying doses as: 0 (control), 4, 6 and 10 J/cm². At the times of 0, 30, 45 and 60 min following irradiation, sperm motilities are assessed by means of computer-aided sperm analysis in all samples. Two additional tests [HOS and sperm chromatin dispersion (SCD) tests] were also performed on the control and high irradiated groups as well. Sperm motility of the control groups significantly decreased after 30, 45 and 60 min of irradiation, while those of irradiated groups remained constant or slightly increased by passing of time. Significant increases have been observed in doses of 4 and 6 J/cm² at the times of 60 and 45 min, respectively. SCD test also revealed a non-significant difference. Our results showed that irradiating human sperms with low-level 830-nm diode laser can improve their progressive motility depending on both laser density and post-exposure time.     

半导体激光痔凝固术对Ⅲ度内痔疗效的探讨

目的探讨半导体激光痔凝固术对Ⅲ度内痔的治疗效果。方法将2004年3月至12月收治的86例Ⅲ度内痔患者分为激光组与痔切除组，进行疗效对比观察。结果激光组术后第1天及第7天疼痛评分均明显低于痔切除组。排便时两组均有少量出血，其中激光组12例，切除组35例，均无需止血治疗。6个月后门诊随访，两组患者痔核脱出均得以纠正，无复发，无肛门失禁，满意度评分激光组患者平均2．8分，痔切除组平均2．6分。结论半导体激光痔凝固术治疗Ⅲ度内痔方法简单、疼痛轻微、安全有效。     

结构化治疗与教育课程对血液透析患者慢性牙周炎的作用

目的开发血液透析患者慢性牙周炎结构化治疗与教育课程(STEP),探讨其对患者牙周健康状态、口腔保健自我效能、牙科畏惧和焦虑、以及全身炎症水平的作用。 方法选取2020年9月至2021年3月北京市某三甲医院的96例确诊为慢性牙周炎的老年血液透析(HD)患者,随机分为对照组和干预组。对于患者的口腔宣教,对照组(48例)使用传统方法,干预组(48例)则使用STEP方法。7个月后分析患者的菌斑指数(PLI)、龈沟出血指数(SBI)、牙周袋探诊深度(PD)、口腔保健自我效能量表(SESS)、牙科焦虑量表(DAS)、牙科畏惧量表(DFS)评分,以及超敏C反应蛋白(hs-CRP)、肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)和转化生长因子β(TGF-β)的变化。 结果与对照组比较,干预组患者的PLI、SBI、PD、SESS、DAS、DFS评分均改善(P<0.05),且hs-CRP、TNF-α水平显著降低(P<0.001),而IL-6、TGF-β指标改善不具有统计学意义。 结论STEP方法显著改善了血液透析合并慢性牙周炎患者的口腔健康状况、自我保健意识、焦虑和畏惧情绪、以及全身炎症水平。     

Optimal solder and power density for diode laser tissue soldering (LTS)

BACKGROUND AND OBJECTIVE: Laser tissue soldering (LTS) using albumin and indocyanine green dye (ICG) is an effective technique utilized in various reconstructive surgical procedures. The purpose of this study was to describe in vivo and in vitro temperature profiles of an albumin-based solder while varying ICG concentration and laser power density (PD), and to describe immediate and short-term tensile strength measurements and histology of tissue with variable ICG concentrations and PD. STUDY DESIGN/MATERIALS AND METHODS: ICG ranged from 0.31 to 20 mg/mL while PD ranged from 3.2 to 63.7 W/cm(2). Direct solder temperature measurements were obtained at 5-second intervals during laser activation. Differential temperature measurements were determined within the dermis of rat skin and the overlying solder. Eighteen rats were subjected to 2.0-cm incisions (n = 113) created on the dorsal skin followed by closure with LTS at varying PD and ICG concentrations. ICG concentrations included 0.31, 2.5, and 20 mg/mL, while PD ranged from 8.0 to 63.7 W/cm(2). Tensile strength (TS) profiles were measured immediately and 10 days post-operatively. Histological examination was performed at the time of sacrifice. RESULTS: Temperature profiles of the ICG/albumin solder differed significantly only at the highest concentration of ICG (20 mg/mL), but showed statistically significant variability at different laser PD. Using solder color changes as an endpoint of LTS, average peak solder temperature ranged from 69 degrees C at a PD of 8.0 W/cm(2), 105 degrees -120 degrees C at PD 15.9-31.8 W/cm(2), and > 200 degrees C at PD > or = 47.7 W/cm(2). Peak intradermal temperatures remained below 50 degrees C at all PDs. Varying ICG concentration only had an effect on the immediate TS of wounds at the lowest power densities. Increasing PD resulted in statistically significant increases in immediate TS up to a PD of 23.9 W/cm(2) at an ICG concentrations of 0.31 and up to a PD of 15.9 W/cm(2) at a concentration of 2.5 mg/mL. Statistically insignificant decreases in 10-day would strength resulted from higher PD. Power densities > or = 23.9 W/cm(2) showed significant thermal injury upon histologic examination. CONCLUSIONS: Power density, not ICG concentration, is the primary determinant of solder and tissue temperature during LTS. Effective and reproducible laser tissue soldering may be achieved primarily by power density control when using diode laser and ICG-based albumin solder. Alterations in PD show the most direct and predictable effects on the healing properties of skin closed by LTS. Optimal laser wound closure occurs with an ICG of 2.5 mg/mL and at a PD between 15.9 and 23.9 W/cm(2).     

Effect of Er:YAG, CO(2) and diode laser irradiation on surface properties of zirconia endosseous dental implants

BACKGROUND AND OBJECTIVES: Zirconia implants (ZI) are becoming more popular in implant dentistry, as a result of their favorable esthetic outcome. However, little is known about the impact laser application has on this material in the course of peri-implantitis treatment. The objective of this investigation was to analyze the influence of Er:YAG, CO(2) and diode laser irradiation on polished ZI. MATERIAL AND METHODS: Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic disks were irradiated at different power settings with either an Er:YAG, CO(2) or diode laser. The surface of the disks was analyzed by scanning electron microscopy (SEM) and confocal 3D white light microscopy (CWLM). In addition energy-dispersive X-ray (EDX) analysis was performed on all disks. Six specimens were used for each parameter set of each laser. RESULTS: SEM analysis demonstrated that, regardless of the power settings, neither the diode laser nor the Er:YAG laser caused any visible surface alterations to ZI. The results of the CWLM were in agreement with the SEM pictures. However, Er:YAG irradiation did penetrate through the disks. At various power settings, the CO(2) treatment was characterized by material cracking and melting. The increased roughness values (from CWLM) of the ZI underlined the SEM observations. CONCLUSION: In contrast to diode and Er:YAG laser irradiation, the CO(2) laser revealed distinct surface alterations to zirconia at various laser parameters. However, the Er:YAG laser cannot be recommended for the treatment of ailing implants, as the laser beam penetrates the material. In this respect, currently, diode lasers seem to be the only laser systems offering surface preservation and safety in the treatment of peri-implantits with ZI.     

Influence of Nd:YAG and diode laser irradiation on apical sealing when associated with AH plus and EndoREZ endodontic cements

OBJECTIVE: This study aims to evaluate the influence of Nd:YAG and diode laser irradiation on apical sealing when applied before root canal filling done with two different resin-based cements (AH Plus and EndoREZ). Background Data: Lasers have been widely used in endodontics. The morphologic changes in dentin walls caused by Nd:YAG and diode laser irradiation could improve sealing ability of endodontic cements. METHODS: Eighty canine teeth were analyzed by apical leakage of methylene blue dye and by scanning electron microscope (SEM) images of the filling's adaptation to the apical third dentin walls. The laser irradiation parameters for the Nd:YAG laser were 100 mJ, 15 Hz, and 1.5 W, and for the diode laser was 2.5 W (continuous mode). RESULTS: The apical leakage results showed statistically significant differences at the 5% level of significance (Tukey's test, p < 0.05) among the different root canal wall treatments, independently of the root canal filling cement used. The cements also showed significant differences between them on the lased groups. The SEM analysis revealed better filling adaptation for AH Plus and the Nd:YAG laser group, confirming the microleakage results. CONCLUSION: We concluded that the combination of the Nd:YAG laser and AH Plus showed the best results.