Diode Lasers

Lipomas of the upper lip are among the rarest adipose tissue neoplasms in the oral cavity. The standard treatment for lipomas involves surgical removal, which can be performed using conventional or laser techniques. This case report discusses a 71-year-old male patient with swelling on the left side of his upper lip, clinically diagnosed as an oral lipoma. The lesion was surgically removed under local anesthesia using a combination of diode laser surgery and a blunt scalpel. This approach facilitated the complete removal of the lesion with reduced operating time, minimal damage to surrounding tissues, and uneventful postoperative healing. Diode laser surgery for benign lipomas presents an effective alternative to traditional methods. The precision and minimal tissue damage it offers are particularly beneficial in aesthetic areas, such as the lips.

Objective: To compare the frequency of pain in root canal treatment using sodium hypochlorite and chlorhexidine as root canal irrigants. Methods: The cross-sectional study was carried out from January to June 2016 at the Pakistan Institute of Medical Sciences (PIMS), Islamabad, Pakistan, and comprised patients aged 18-40 years with irreversible pulpitis involving a posterior tooth. The patients were divided into two equal groups, with Group-I receiving 2% chlorhexidine, and Group-II receiving 5.25% sodium hypochlorite. Following the use of the irrigants, the selected teeth were evaluated for pain at 72 hours using Visual Analogue Scale. Results: There were 60 patients divided into groups of 30(50%) each. The overall mean age was 27.97±5.9 years. There were 32 (53.3%) females and 28 (46.6%) males. The mean post-operative pain score was 1.70±1.9 in Group-I and 1.90 ± 2.3 in Group-II (p=0.5). In Group-I, 25(83.3%) patients had no pain while in Group-II, 20(66.7%) had no pain (p=0.1). Conclusions: There was no difference in post-operative pain at 72 hours between 2% chlorhexidine and 5.25% sodium hypochlorite when used as irrigants.

Compact, tunable, low-power consumption coupled-cavity lasers are designed and experimentally demonstrated. Single-mode operation with an SMSR >24 dB and >11 nm tuning range are achieved, being suitable as on-chip local oscillators in low-power integrated optical coherent receivers.

Diode laser-based two-line atomic fluorescence (TLAF) thermometry applied to flames of combusting wood pellets is demonstrated. The pellets are placed in the hot product gas (O2 concentration 1.7%) of gallium seeded laminar flames stabilized on a multi-jet burner. The calibration-free technique provides one dimensional spatial temperatures with sufficient temporal resolution to resolve all combustion stages of a pellet even in highly sooting flames. The temperature above a burning pellet was found to decrease due to the release of volatile gases and the accuracy and precision of the technique is assessed at flame temperatures.

Lead-salt diode lasers have been commercially available for more than two decades and became essential for laser mid-infrared gas analysis with high sensitivity and selectivity. Their emission covers the wavelength range from below 3 µm to more than 20 µm. Continuous emission is observed to above 200 K, and pulsed emission to above 80 ◦C. Their main advantage over other materials is a two orders of magnitude lower Auger recombination rate. Basic material properties, the present state-of-the-art lead-salt lasers and trends and possibilities are discussed.

Objectives A comparison of different treatment modalities of peri-implantitis can lead to the development and application of more effective and efficient methods of therapy in clinical practice. This study compares the effectiveness of open flap debridement used alone, with an approach employing the additional use of a diode laser for the treatment of peri-implantitis. Materials and methods Nineteen patients were divided into two groups and treated for peri-implantitis. In the control group (C group), the therapy utilized access flaps, plastic curettes, and sterilized gauzes soaked in saline. The test group (L group) was treated similarly but with additional irradiation using a diode laser. The parameters studied were pocket depth (PD) as the primary outcome variable, clinical attachment level (CAL), bleeding on probing (BOP), and plaque index (PI) as secondary variables. Measurements were performed at three different time points, baseline (BSL), 3 months, and 6 months after treatment. Three months after treatment, a mean PD reduction of 1.19 mm for the control group and 1.38 mm for the laser group was recorded. The corresponding BOP changes were 72.9 and 66.7 %, respectively. These changes were significant and remained at the same levels at the 6-month examination (p<0.05). CAL was reduced significantly only in group L from 5.25 mm at baseline to 4.54 mm at 3 months, remaining at this level at 6 months (p<0.05). PI was reduced significantly in group C at 3 months from 37.5 to 6.3 %. The 6-month data showed no statistically significant difference (p<0.05) from the 3-month measurements. Results The two methods of therapy for peri-implantitis examined seemed to be equally efficient in the reduction of the PD and BOP 3 months after surgery, with the results sustained at the same levels after 6 months. CAL significantly improved only in the test group after 3 months. PI was reduced and maintained at low levels in both groups. Conclusions Surgical treatment of peri-implantitis by access flaps leads to improvement of all clinical parameters studied while the additional use of diode laser does not seem to have an extra beneficiary effect. Clinical relevance The additional use of a diode laser in the surgical treatment of peri-implantitis offers a limited clinical benefit.

Frequency converters are used in wind turbines because they make it possible to apply the variable-speed concept. They also make it possible for wind farm to become active element in the power system. The traditional frequency converter is back-to-back connected two level converters, in which the output voltage has two possible values. However, the output voltage is smoother with a three-level converter, where output voltage has three possible values. This results in smaller harmonics, but on the other hand it has more components and is more complex to control. Multilevel inverter machinery has emerged recently as a very important alternative in the area of high power medium-voltage control and also for improving the total harmonic distortion by reducing the harmonics. Generally, the poor quality of voltage and current of a conventional inverter fed induction machine is obtained due to the presence of harmonics and hence there is a significant level of energy losses. The objective o...

High power diode laser bars are interesting in many applications such as solid state laser pumping, material processing, laser trapping, laser cooling and second harmonic generation. Often, the free running laser bars emit a broad spectrum of the order of several nanometres which limit their scope in wavelength specific applications and hence, it is vital to stabilize the emission spectrum of these devices. In our experiment, we describe the wavelength narrowing of a 12 element 980 nm tapered diode laser bar using a simple Littman configuration. The tapered laser bar which suffered from a big smile has been "smile corrected" using individual phase masks for each emitter. The external cavity consists of the laser bar, both fast and slow axis micro collimators, smile correcting phase mask, 6.5× beam expanding lens combination, a 1200 lines/mm reflecting grating with 85% efficiency in the first order, a slow axis focusing cylindrical lens of 40 mm focal length and an output coupler which is 10% reflective. In the free running mode, the laser emission spectrum was 5.5 nm wide at an operating current of 30A. The output power was measured to be in excess of 12W. Under the external cavity operation, the wavelength spread of the laser could be limited to 0.04 nm with an output power in excess of 8 W at an operating current of 30A. The spectrum was found to be tuneable in a range of 16 nm.

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We report on NIR efficient end-coupling in single-mode silicon on insulator waveguides. Efficient coupling has been achieved using Polymer-Tipped Optical Fibers (PTOF) of adaptable radius of curvature (ROC). When compared with commercial micro lenses, systematic studies as a function of PTOF ROC, lead for subwavelength PTOF to a coupling factor enhancement as high as 2.5. This experimental behavior is clearly corroborated by radial FDTD simulations and an absolute coupling efficiency of about 50% is also estimated. OCIS codes: (130.0130) Integrated optics; (230.0230) Optical devices.

We report on NIR efficient end-coupling in single-mode silicon on insulator waveguides. Efficient coupling has been achieved using Polymer-Tipped Optical Fibers (PTOF) of adaptable radius of curvature (ROC). When compared with commercial micro lenses, systematic studies as a function of PTOF ROC, lead for subwavelength PTOF to a coupling factor enhancement as high as 2.5. This experimental behavior is clearly corroborated by radial FDTD simulations and an absolute coupling efficiency of about 50% is also estimated.

In this paper, operating principles of regulated AC to DC converters have been discussed and the simulation results are provided. The circuit is built and simulated by Proteus software. The characteristics of half wave, centre tap and bridge rectifiers under forward and reverse directions was simulated and their output waveforms was analyzed. The key components used for the construction are step down transformer, diode, capacitor, zener voltage regulator, and output load resistor. The circuit was design using stage by stage approach which comprised four modules. These include: 220V to 12V step down transformer, rectifier, DC filter and regulator circuits. The stepdown transformer was used to transform 220V voltage AC input into 12V voltage AC output. The Rectifier circuit was used to convert this low voltage AC into pulsating DC voltage output that consists of ripple components. We then connected a capacitor of a high capacitance to the output of the rectifier, to filter the pulsating DC voltage to produce pure DC voltage. Due to unwanted input fluctuations, we connected 12V zener diode regulator to maintain the output voltage at a constant 12V value. The simulation results show that for half wave rectifier only half of the input ac waveform appeared across the load while for the centre tap and the bridge rectifiers both positive and negative half cycles of the input AC waveforms are allowed. The results obtained from simulation are compatible with the actual experiments.

Practical demonstrations of diode laser emission from the broad surface area rather than from the cleaved facet of the wafer are relatively recent. This is so despite the fact that the concepts are many years old. The vertical-cavity approach was demonstrated by Melngailis in 1964, and the grating surface emitting and folded-cavity approach were reported by many authors in the mid to late 1970s. Many, perhaps most, of the concepts discussed in this book were around for many years before they were actively pursued. The advances over the last ten years, mainly in materials, are largely responsible for the capability to implement the ideas presented into working devices. We can look forward to continued progress in materials, processing, and design during the next decade and can expect to see semiconductor laser performance outstripping even our present dreams.
There are now frequent reports on all three principal types of diode laser
and diode laser array surface emitters in the literature. Unlike edge-emitting
semiconductor lasers, the surface emission approach allows the use of mass production techniques throughout the fabrication process. In addition, the surface emission approach allows testing of the completed devices at the wafer level, before dicing and packaging. These same capabilities yielded tremendous reductions in cost and enormous increases in the performance and reliability of transistors and other solid state electronic devices. Surface-emitting approaches also allow the integration of single or numerous lasers to form photonic integrated circuits or high power, monolithic, two-dimensional arrays.
Because of the now extensive literature on surface-emitting diode lasers
and arrays and the proposed and emerging applications of these exciting and
practical new devices in a variety of systems, we feel that this in-depth book
covering the field will be useful to researchers, users, and students interested in the field of lasers, electrooptics, and optical communication. Recent work has been motivated by numerous goals, including low power, integrated sources to replace electrical interconnects with optical interconnects for ultra large-scale integrated circuits; two-dimensional, independently addressable laser arrays for neural networks; steerable output beams for optical computers; high power with large emitting areas for pumping solid-state lasers; and coherent, single frequency, high-power operation with a controlled output beam for space communication and second harmonic generation.
The information in this book is intended to provide the reader with both
knowledge about fundamental concepts and the present state of the art of surface-emitting lasers. There are definitive chapters on vertical-cavity, etched facet-mirror, and grating surface emitters. Additional chapters treat the operation of Bragg grating couplers; edge-emitting diode laser arrays; the theory of phase locking, modes, and beam steering of surface-emitting arrays; external methods of phase locking arrays; coherence and phase control in laser arrays; and thermal considerations in two-dimensional surface-emitting arrays.
We have fortunately been able to enlist some of the leading researchers and
developers of surface-emitting diode lasers to contribute to this book. We wish to thank them for many interesting and productive discussions in connection with the preparation of this work. We also wish· to thank RCA Laboratories (now the David Sarnoff Research Center), Princeton, New Jersey, for providing both of us with talented collaborators, up-to-date equipment, and a pleasant environment in which most of our work described herein was carried out.

Acute exacerbations of pericoronitis is associated with debilitating symptoms, and requires urgent intervention. Mechanical debridement, operculectomy and antibiotic therapy are parts of established treatment protocol, however, associated with many limitations. This report highlights successful management of a case of pericoronal abscess around mandibular third molar in a 30-year-old female, with GaAlAs diode laser-assisted disinfection and operculectomy. Although infection was initially associated with lymphadenitis and fever, postoperaive period was symptom free, even without use of antibiotics. Due to many intraoperative and postoperative advantages and better patient acceptance, diode laser has become a preferred option for minor oral surgical procedures.

We present a novel multi-dimensional positional encoder approach that uses range-resolved interferometry (RRI) to simultaneously interrogate multiple interferometers differing in optical path length, using only a single photo detector and a single diode laser. Employing only stage-mounted non-polarising beamsplitters and reflections from three orthogonal, externally mounted, planar mirrors, three Cartesian measurement directions are formed, that when combined with measurements from a stage-mounted reference reflection, allow for three-dimensional measurements of stage motion obtained via a single access port. Through a variety of movements of a three-dimensional Piezo-electric stage over its nominal stage working range of ±50 µm, simultaneous measurements of displacements from three orthogonal dimensions are acquired with a 10 kHz quadrature bandwidth, achieving typical displacement noise densities of below 0.4 nm/ √ Hz, with the noise floor dropping to below 0.1 nm/ √ Hz above 50 Hz, as well as high linearity with cyclic errors amplitudes well below 1 nm in all three directions.

The use of the carbon dioxide laser in the oral cavity for ambulatory patients is presented. Excision and vaporization were successfully used for the treatment of benign tumors, vascular proliferations, reparative and granulomatous lesions, mucosal lesions (mucocutaneous diseases, pigmented and premalignant epithelial states), salivary cysts and stones, and for surgical procedures including preprosthetic preparation of the jaws, exposure of dental implants, and gingivectomies. The CO 2 laser was used with a handpiece for excision and vaporization. An accessory instrument, SwiftLase, was used for char-free tissue ablation. The CO 2 laser has the ability to perform accurate hemostatic surgery with minimal postoperative pain and edema. These advantages are particularly important in the treatment of the ambulatory patient. Lasers have been used in medicine for approximately 20 years. The first report of carbon dioxide (CO2) surgery appeared in the dental literature in 1979." Since that time, developments in oral soft-tissue lesion excision, osteosurge!y, and malignant tumor surgery have been re-23 ported. ' The CO 2 laser has been shown to have several advantages over other surgical instruments in the practice of oral and maxillofacial surgery. 4"5 The CO 2 laser beam has a wavelength of 10.6 ~m, which is well-absorbed by water and, hence, by tissues that have a high water content, such as the oral soft tissues. The absorbed energy causes vaporization of the intracellular and extracellular fluid and destruction of the cell membranes. 3 The CO2 laser can be used in three ways: with a focused beam, the laser is used as a "light knife" for performing hemostatic incisions; with a defocused beam, for vaporization and debulking of tissue; and with the SwiftLase, a CO2 laser accessory for rapid scanning of the laser beam on tissue that creates a wide, shallow char-free treatment site by precisely controlling ablation depth without causing residual thermal damage to tissues. CO2 laser surgery for soft-tissue lesions in the oral cavity accomplishes noncontact hemostatic surgery and decreases postoperative edema and pain. 6'7 The purpose of this article is to discuss the use of the CO 2 laser in oral maxillofacial procedures for ambulatory patients.

The effect of different polishing systems on the surface roughness of a nanocomposite and a microhybrid composite. 258 The availability of the basic oral health care package in the Western Cape CASE REPORT 271 Managing sodium hypochlorite accidents: the reality of toxicity The crocodile (suborder Crocidylinae) is a semiaquatic reptile. The jaws are of equal size and the lower teeth are fitted along the edge of the upper jaw when the mouth is closed. Hence these teeth are visible, as opposed to the alligator. The lower fourth tooth fits into a groove in the upper jaw, a speciesdefining characteristic. Crocodiles are polyphyodont, and can replace each tooth up to 50 times during their lifetimes of 35 to 75 years, reliant upon the stimulation of odontogenic stem cells that are found in the dental lamina.

Photobiomodulation (PBM), also known as low level laser therapy (LLLT) or cold laser therapy uses light energy to elicit biological responses from the cell and help regulate cell function. From a clinical point of view PBM oers dental practitioners a non-invasive treatment modality that can be used as an adjunct to the traditional therapies or as a therapeutic tool on its own. This is a case of surgical excision of a uctuant mass using a scalpel and diode laser 980nm wavelength.

1) Background: The present pilot in vitro study evaluated, physically and biologically, the effects produced by the wear of the titanium surface using different drill models. (2) Methods: Titanium disks were subjected to wear using four different burs and accordingly divided into the following test groups (n = 12 disks per group): Tungsten Burs (TB group), Tungsten Carbide Burs (TCB group), Coarse-Grained Diamond Burs (CGB group), and Fine-Grained Diamond Burs (FGB group). As a control group (CON group), titanium disks with a smooth surface (machined) were used. The samples were subjected to atomic force microscopy (AFM), profilometry analysis, scanning electron microscopy (SEM), and cell viability and adhesion assessments. (3) Results: The values of the measured roughness parameters showed statistical differences among the five groups (p = 0.0035 for Ra and p = 0.0010 for Rz). All test groups showed an important difference statistically (p = 0.0032) to the CON group for the cell viability and adhesion analysis. The data of cell absorbance at 570 nm were 0.4122 ± 0.05 for the CON group, 0.1354 ± 0.02 for the TB group, 0.123 ± 0.01 for the TCB group, 0.1414 ± 0.02 for the CGB group, and 0.1216 ± 0.03 for the FGB group. Additionally, the cell count showed the following adherence percentages: 57.6 ± 4.6% for the CON group, 22.9 ± 3.3% for the TB group, 23.4 ± 2.9% for the TCB group, 22.5 ± 3.1% for the CGB group, and 23.7 ± 3.3% for the FGB group. However, no statistical differences were found among the four test groups analyzed (p = 0.3916). ( ) Conclusions: The results showed that the changes produced on the surface by the four different bur models altered the topography characteristics and affected the cell viability and adhesion in comparison with the control group.

The efficiency limiting mechanisms in type-I GaInAsSb-based quantum well (QW) lasers, emitting at 2.3, 2.6 and 2.9 µm, are investigated. Temperature characterization techniques and measurements under hydrostatic pressure identify an Auger process as the dominant nonradiative recombination mechanism in these devices. The results are supplemented with hydrostatic pressure measurements from three additional type-I GaInAsSb lasers, extending the wavelength range under investigation from 1.85 to 2.90 µm. Under hydrostatic pressure, contributions from the CHCC and CHSH Auger mechanisms to the threshold current density can be investigated separately. A simple model is used to fit the nonradiative component of the threshold current density, identifying the dominance of the different Auger losses across the wavelength range of operation. The CHCC mechanism is shown to be the dominant nonradiative process at longer wavelengths (> 2 µm). At shorter wavelengths (< 2 µm), the CHSH mechanism begins to dominate the threshold current, as the bandgap approaches resonance with the spin-orbit split-off band.

This research was aimed to conduct the drilling direction with computerized machines, the design and construction of an automatic lathe involves the development of a mechanical system, an electronic system and a computer system, which are to interact to mold a material, guided by an input CNC code. The development of a system with mechanical, electronic and computational components corresponds to a mechatronic system.

In this paper we study laser diode parameters in fiber optic communication system and we study the relationship between them. The capacity of optical communication systems is rising exponentially in order to follow the rapidly increasing demand for data traffic. Limitations due to dispersion and non-linearity in the optical fiber become more stringent for higher bit rates.. In optical communication transmitters are light sources, receivers are light detectors and the channels are optical fibers. In optical communication the channel i.e., optical fiber plays an important role because it carries the data from transmitter to the receiver. Laser is a powerful source of light having extraordinary properties which are not found in the normal light sources like tungsten lamps, mercury lamps, etc..Laser surgery has also provided itself to be a preferred tool of operation over standard tools in a lot of the cases.

Ankyloglossia or tongue-tie is the result of a tight and short lingual frenulum which causes difficulty in breast feeding, eating and speech articulation due to limited tongue movement. In this condition, the tip of the tongue cannot be protruded beyond the lower incisor teeth because of a short lingual frenum. In this article, we have reported a 26 year old female patient with tongue-tie who complained of difficult in speech. She underwent frenectomy procedure under local anaesthesis without any complications. This was followed by speech therapy sessions.

Introduction: The intent of the present research was to evaluate the antibacterial efficacy of the two different powers of diode laser and photodynamic therapy PDT by utilizing toluidine blue alone and in combination against Enterococcus faecalis. Methods: The research was done on seventy five human extracted incisor teeth. Their crowns were removed at cementoenamel junction CEJ then the roots were cleaned and shaped. After autoclaving of the roots, they were injected and infected with Enterococcus faecalis for 72 hours. They were divided randomly to five equal categories according to type of treatment used. Group (I), high power diode laser with wave length 980 nm and output power 2 W for one minute. Group (II), toluidine blue TBO photosensitizer for five minutes. Group (III), low power 635 nm diode laser with output power 220 mw for 30 seconds. Group (IV), toluidine blue was activated by low power diode laser 635 nm and output power 220 mw for 30 seconds. Group (V), toluidine blue was activated by 980 nm diode laser and output power 2 W for one minute. Results: Antibacterial efficacy was assessed before and after treatment. 980 nm diode laser reduced bacteria by 86.4 %, toluidine blue reduced it by 19.19%, 630 nm diode laser reduced it by 13.95%, toluidine blue plus low power 635 nm diode laser reduced it by 88.13 %, and toluidine blue plus high power 980 nm diode laser reduced it by 97.76 %. Conclusion: The most bacterial reduction was found in group toluidine blue plus high power 980 nm diode laser (group V). The combined technique could be an effective modality for elimination of Enterococcus faecalis from the root canals.

AIM: To find the best method for applying the diode laser 810 nm to relieve post-endodontic pain on necrotic maxillary incisors with periapical lesions within a single-visit treatment. METHODS: Eighty patients with a necrotic incisor, diagnosed with asymptomatic apical periodontitis, received standardized cleaning and shaping procedures, then divided randomly with a 1:1:1:1 allocation ratio into four groups: Group 1: control group with no laser application, Group 2: applying the diode laser as an irrigation activation system (IAS), Group 3: applying the diode laser from the buccal and palatal mucosa, Group 4: applying the diode laser as an IAS and from buccal and palatal mucosa. The postoperative pain was assessed using the visual analog scale (VAS) 1, 3, 7, and 14 days after the treatment. The mean values of the VAS score were statistically analyzed used Kruskal-Walis and Mann-Whitney U tests. The level of significance was set at a = 0.05. RESULTS: During 14 days after treatment, there was a statistically significant difference between mean values of VAS scores in the four groups (P value < 0.05); Group 1 scored the highest score, whereas Group 4 showed the lowest one. Moreover, Group 4 showed favorable outcomes compared with Group 2 and Group 3 during the first three days after treatment. CONCLUSION: Diode laser reduced postoperative pain after necrotic teeth with large-sized apical lesion treatment, whereas using diode laser either as an IAS or LLLT reduced the postoperative pain compared with the control group. Moreover, the usage of a diode laser in both previous techniques represents the best protocol for postoperative pain relief during 14 days of treatment. CLINICAL RELEVANCE: The clinical significance of this study is to investigate the best method to reduce postoperative pain using diode lasers 810 nm; where the results of this study indicated that the more diode laser exposer in LLLT and IAS, the less postoperative pain after endodontic procedures.

Introduction: epidemiological studies related to secondary glaucoma all over the world, as it is the case of neovascular one, they are rare when compared with simple chronic glaucoma. Development: a literature review on diagnosis and treatment of neovascular glaucoma was carried out. Decision trees technique, based on medical histories of patients as well as the results of the multivariate statistical analysis of the study was used. The results of the statistical and theoretical analysis were presented which facilitated the achievement of decision trees as an expression of diagnosis and treatment uniformity.

Background: Photodynamic therapy (PDT) is a technique that uses light and a photosensitizer, converting local molecular oxygen into singlet oxygen, which eliminates a target unhealthy tissue. It has been increasingly used for the treatment of several diseases including skin disorders. Psoriasis is a chronic inflammatory skin disease expressing immune and hyperproliferative features. Objective: This study aimed to evaluate the effect of the photosensitizer 5,10-diphenyl-15,20di(N-methylpyridinium-4-yl)porphyrin (Di-cis-Py+) in in vivo models whereby some psoriasis-like parameters could be investigated. Methods: The antiinflammation and antiproliferative activities of Di-cis-Py+ photoactivated was measured by myeloperoxidase (MPO) and N-acetyl-␤-D-glucosaminidase (NAG) enzyme activity assay, measurement of IL-6, IL-1␤ and TNF-␣ levels, evaluation of proliferating cell nuclear antigen (PCNA) levels by immunohistochemistry and by Western blot. Results: Treatment involving PDT and Di-cis-Py+ resulted in reduction of edema, cellular infiltration, proinflammatory cytokines, as well as reduced hyperproliferation of the epidermis. All the evaluated parameters were promoted by topical application of phlogistic agents and are similar to that observed in lesions of psoriatic skin.

A single-step, low-cost fabrication method to generate resonant nano-grating patterns on poly-methyl-methacrylate (PMMA; plexiglas) substrates using thermal nano-imprint lithography is reported. A guidedmode resonant structure is obtained by subsequent deposition of thin films of transparent conductive oxide and amorphous silicon on the imprinted area. Referenced to equivalent planar structures, around 25% and 45% integrated optical absorbance enhancement is observed over the 450-nm to 900-nm wavelength range in one-and two-dimensional patterned samples, respectively. The fabricated elements provided have 300-nm periods. Thermally imprinted thermoplastic substrates hold potential for low-cost fabrication of nano-patterned thin-film solar cells for efficient light management.

The clinical management of the epulis involves the elimination of causal factors, excision of fibrous tissue excess accompanied by an appropriate prosthetic rehabilitation. The confection of interim prosthesis or the rectification of old prosthesis for the setting up of a tissue conditioner if necessary, to improve the healing and prevent the decrease of the vestibule depth after the surgical exeresis. Throughout this paper, we are going to present a new technique for the correction of old prostheses poorly adapted for the management of a case of the epulis fissuratum.

Background: Enterococcus faecalis has been widely used as a valuable microbiological pathogen for in vitro studies due to its ability to successfully colonize the root canal in a biofi lm-like style, invade dentinal tubules, and resist endodontic treatment procedures.The aim of this study was to compare the bactericidal effi cacy of photodynamic therapy (PDT), 2% chlorhexidine, 2.5% NaOCl, and combination of PDT and 2.5% NaOCl against E. faecalis. Materials and Methods: Sixty single-rooted teeth had their canals contaminated with E. faecalis in brain heart infusion broth and were incubated for 48 hours.The canals were then subjected to 2% chlorhexidine, 2.5% NaOCl, PDT (red light emitting diode 625 nm+ Toludine Blue) and PDT + 2.5% NaOCl. Controls consisted of no treatment (positive control) and without inoculation of bacterium (negative control). Following treatment, the canal contents were sampled with sterile paper points. The samples were dispersed in transport medium, serially diluted, and cultured on blood agar to determine the number of colony forming units (CFU). Data were analyzed by Mann-Whitney U test at 5% signifi cance level. The signifi cance level for all analyses was set at P <.05. Results: Combination of PDT and 2.5% NaOCl achieved maximum reduction in recovered viable bacteria, no viable bacteria was observed after treatment of PDT + 2.5% NaOCl. Conclusion: Combination of PDT and 2.5% NaOCl simultaneously is effective in the elimination of E. faecalis from dentinal tubules under the conditions of this study.

OBJECTIVE: The objective of this review is to describe basic diode laser physics and to delineate the application of diode lasers in dentistry. REVIEW: Over the past few decades lasers have become a popular alternative to conventional methods owing to the advantages they carry such as decreased cellular destruction and tissue swelling, minimal bleeding, enhanced visualization of surgical sites and reduced requirement for suturing. Among the various lasers in dentistry, diode lasers are currently the most commonly used, with applications extending from soft tissue procedures to photo-activated disinfection of periodontal pockets, endodontics and laser-assisted tooth whitening. With its versatility and numerous benefits, small size, ease of operation and, relative and cost-effectiveness when compared to other lasers, the diode laser is proving itself as a valuable addition to dental setups. CONCLUSION: The diode laser provides a relatively pain-free minimally invasive technique for removal of soft tissue lesions such as exophytic lesions and operculum, gingival depigmentation, implant exposure, biostimulation, canal disinfection in endodontics and teeth whitening.

This study aims to evaluate the bacterial reduction after conventional root canal treatment using 5.25% sodium hypochlorite. Materials and Methods: The study criteria included 100 patients requiring root canal treatments due to pulpitis. The diagnosis was made based on objective clinical signs (examination, probing, percussion, palpation) and X-ray investigation. The clinical procedures were carried out under strict aseptic precautions. All patients were subjected to biomechanical preparation followed by irrigation using sodium hypochlorite at a concentration of 5.25% which is considered the highest concentration without causing any toxic effect on the patient. All microbiological samples were taken immediately after the access preparation baseline (S1) and after the completion of the root canal instrumentation and disinfection with 5.25% sodium hypochlorite (S2) and sent for microbiological analysis. Results: One hundred patients with infected root canal were selected for this in vivo study. All S1 samples were positive for microbial isolates, 71 samples harbored cultivable bacterial isolates, 22 were fungus (Candida albican), and 7 samples showed no growth so in total adding up to 151 isolates identified from 100 patients. Bacterial isolates before chemomechanical treatment showed the highest prevalence belonging to Enterococcus faecalis followed by Streptococci, Staphylococci and Candida albican. After the chemomechanical treatment with 5.25% of sodium hypochlorite no cultivable bacteria were isolated from 38 patients root canals, and therefore the treatment managed to eradicate 54% of the 151 isolated bacterial species from the 71 infected root canals. Conclusion: The antimicrobial effect of 5.25% sodium hypochlorite was effective in eradicating a high number of the bacterial isolates along with the fungus identified in infected root canals. This high concentration of sodium hypochlorite presented no toxic damage to the root canal or the area around it when handled with care.

Aim: Frenulum is a sagittal fibrous fold of oral mucosa with a periosteal insertion that extends from the lip or cheek to the alveolar or gingival mucosa. Sometimes frenulums have high attachments and wide soft tissue folds and these high frenulums may cause functional and aesthetic problems. The aim of this study is evaluate the pain and discomfort in patients treated with conventional or diode laser frenectomy through VAS scale. Material-method: In this study, in totally 74 patients frenectomy procedure was indicated. 39 patients had frenectomy performed with conventional surgery (Group C) and 35 patients had frenectomy performed with laser surgery (Group L). None of the patients had systemic disease or any prescribed drug use. A VAS scale was prepared in order to evaluate pain and discomfort in speaking and chewing. All patients were informed about how to fill the form in detail and a form was given to each patient. All patients were recalled at 10 th day and VAS scale forms were recollected. Results: There were no significant differences in demographic data of the groups (p>0.05). Pain was found to be significantly higher in conventional group (p<0.05). Likewise, discomfort in speaking and chewing was also significantly lower in laser surgery group than conventional surgery (p<0.05). Conclusion: Diode laser frenectomy procedure caused lower pain and discomfort in speaking and chewing, and within the limitations of this study, based on these results it can be concluded that diode laser surgery had beneficial results in frenectomy procedure.

Introduction: Photodynamic therapy (PDT) is now a widely used treatment modality in many fields of dentistry, including endodontics. The most common application of PDT in endodontics is to disinfect root canals. The purpose of this study was to present the experience of using PDT in root canal disinfection of three patients. Case Presentation: Three patients referred to the Endodontics Department of Shahid Beheshti University of Medical Sciences were treated using 0.1 mg/mL Toluidine Blue (FotoSan® agent; CMS Dental, Denmark) irradiated with a light-emitting diode (LED) lamp (FotoSan®; CMS Dental, Denmark) with a mean wavelength of 630 nm and a mean power density of 3 W/cm2 over two 30-second periods. Conclusion: PDT using LED lighting can be used in conjunction with conventional root canal treatment (RCT) to achieve great results.

High power diode laser bars are interesting in many applications such as solid state laser pumping, material processing, laser trapping, laser cooling and second harmonic generation. Often, the free running laser bars emit a broad spectrum of the order of several nanometres which limit their scope in wavelength specific applications and hence, it is vital to stabilize the emission spectrum of these devices. In our experiment, we describe the wavelength narrowing of a 12 element 980 nm tapered diode laser bar using a simple Littman configuration. The tapered laser bar which suffered from a big smile has been "smile corrected" using individual phase masks for each emitter. The external cavity consists of the laser bar, both fast and slow axis micro collimators, smile correcting phase mask, 6.5× beam expanding lens combination, a 1200 lines/mm reflecting grating with 85% efficiency in the first order, a slow axis focusing cylindrical lens of 40 mm focal length and an output coupler which is 10% reflective. In the free running mode, the laser emission spectrum was 5.5 nm wide at an operating current of 30A. The output power was measured to be in excess of 12W. Under the external cavity operation, the wavelength spread of the laser could be limited to 0.04 nm with an output power in excess of 8 W at an operating current of 30A. The spectrum was found to be tuneable in a range of 16 nm.

A single-pass frequency doubled high-power tapered diode laser emitting nearly 1.3 W of green light suitable for direct pumping of Ti:sapphire lasers generating ultrashort pulses is demonstrated. The pump efficiencies reached 75 % of the values achieved with a commercial solid-state pump laser. However, the superior electro-optical efficiency of the diode laser improves the overall efficiency of the Ti:sapphire laser by a factor > 2. The optical spectrum emitted by the Ti:sapphire laser shows a spectral width of 112 nm (FWHM). Based on autocorrelation measurements, pulse widths of less than 20 fs are measured. These results open the opportunity of establishing diode laser pumped Ti:sapphire lasers for e.g. biophotonic applications like retinal optical coherence tomography or pumping of photonic crystal fibers for CARS microscopy.

For the first time a single-pass frequency doubled DBR-tapered diode laser suitable for pumping Ti:sapphire lasers generating ultrashort pulses is demonstrated. The maximum output powers achieved when pumping the Ti:sapphire laser are 110 mW (CW) and 82 mW (modelocked) respectively at 1.2 W of pump power. This corresponds to a reduction in optical conversion efficiencies to 75% of the values achieved with a commercial diode pumped solid-state laser. However, the superior electro-optical efficiency of the diode laser improves the overall efficiency of the Ti:sapphire laser by a factor > 2. The optical spectrum emitted by the Ti:sapphire laser when pumped with our diode laser shows a spectral width of 112 nm (FWHM). Based on autocorrelation measurements, pulse widths of less than 20 fs can therefore be expected.

Splitting of a dc voltage source with two capacitors has been the approach in generating 5-level output voltage with single-and three-phase full-bridge circuits and added bidirectional switch. Associated with this configuration is the problem of voltage imbalance between the splitting capacitors. In addition, the inverter output voltage magnitude is obviously limited to the value of the split input voltage source. Presented in this paper is a unit topology for single-phase 5-level multilevel inverter, MLI. It simply consists of a full-bridge circuit, a capacitor, charge-discharge unit and a dc source. The charge-discharge unit with the capacitor is the interface between the fullbridge and the dc source. The proposed unit cell can generate a 5-level output voltage waveform whose peak value is twice the input voltage value. For higher output voltage level, a cascaded structure of the developed unit cell is presented. Comparing the proposed inverter with CHB inverter and some recent developed MLI topologies, it is found that the proposed inverter configuration generates higher output voltage value, at reduced component-count, than other topologies, for a specified number of dc input voltages. For two cascaded modules, simulation and experimental verifications are carried out on the proposed inverter topology for an R-L load.