1,720,972 research outputs found
Er:YAG Laser: A New Technical Approach to Remove Torus Palatinus and Torus Mandibularis.
No full textObjective. The aim of this study was to assess the ability of Er:YAG laser to remove by excision torus mandibularis and to smooth torus palatinus exostosis. Materials and Methods. Torus mandibularis (TM) and torus palatinus (TP) were surgically eliminated via the Er:YAG laser using the following parameters: TM: output power ranging from 500 to 1000 mJ, frequency from 20 to 30 Hz, sapphire tips (diameter 0.8 mm), air-water spray (ratio 5/5), pulse duration 150 μsec, fluence ranging from 99592 J/cm(2) to 199044,586 J/cm(2). TP: a peeling technique was used to eliminate TP, as excision by slicing being impossible here. Results. TM: excision was obtained after 12730 pulses. TP: smoothing technique took more time compared with excision. Once peeling was considered to be accomplished, the use of a surgical rasp was necessary to eliminate bone spicules that could delay the wound to heal in good conditions. Conclusion. Er:YAG excision (TM) or Er:YAG peeling (TP) are safe clinical techniques easy to practice even if the time required for excision or surface smoothing is more than the time required with bony burs and high speed instruments
Use of laser in orthodontics: applications and perspectives
No full textLaser technology got in these years a more and more important role in modern dentistry and, recently, also in orthodontics was proposed the utilization of laser devices. The aim of this work is to describe the utilization of this technology both in soft and hard oral tissues to improve orthodontic treatment. Several cases, with different wavelengths (532, 810, 980, 1064, 2940 and 10600 nm) and in different times of the treatment (before, during and after) are presented. All the cases reported showed, according to the literature, that the use of the laser related to orthodontic treatment offers several advantages when compared with conventional methods. In the soft tissues surgery it allows to reduce or eliminate the use of anesthetic injection, to avoid use of sutures and to bond bracket in dry enamel; associated with orthophosphoric acid, it gives a stronger adhesion of the brackets to the enamel and, in the case of porcelain brackets, it detaches them without damages; at low power (LLLT) it permits to control the pain of the first period after bonding and, by increasing the speed of teeth movement in the bone, reduces the time of the treatment
Thermal increase in the oral mucosa and in the jawbone during Nd:YAG laser applications. Ex vivo study.
No full textOBJECTIVE:
Literature reports bactericidal and biostimulant effects for Nd:YAG laser procedures on bone and oral mucosa but the possible overheating can cause damage to anatomical structures. The aim of the study was to evaluate the is the evaluation of thermal increase in different levels of oral tissues: mucosa, periosteum and bone during defocused application of Nd:YAG laser at different parameters.
STUDY DESIGN:
Superficial thermal evaluation was performed in pig jaws with a thermal camera device; deep thermal evaluation was realized by 4 thermocouples placed at a subperiosteal level and at 1,2 and 4 mm depth in the jaw bone. Laser applications of 1 minute were performed 5 times (with a pause of 1 minute) on a surface of 4 cm2 with a Nd:YAG laser (MSP mode, 320 micrometer fiber, defocused mode) with different parameters. Temperatures were recorded before and after laser applications and after each pause in order to evaluate also the thermal relaxation of tissues.
RESULTS:
At submucosal level, mean thermal increase was between 1.1°C and 13.2°C, at 1 mm depth between 1.1°C and 8.5°C, at 2 mm depth between 1.1°C and 6.8°C, at 4 mm depth between 1.0°C and 5.3°C. Temperature decrease during the rest time period was variable between 0°C and 2.5°C.
CONCLUSIONS:
Temperatures reached during clinical procedures with parameters reported in the literature in biostimulation protocols (1.25-2 Watts) for the five minutes of application are not dangerous for biological structures. The decrease in temperature during the rest time period is less considerable in the bone in comparison to oral mucosa
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Intraoral metal laser welding: a case report.
No full textThe possibility of laser welding of dental prostheses offers great advantages: first, the operator has the possibility of welding on the master model, which decreases the number of passages and thus the possibility of errors and damage, and secondly, the patient attends only a few sessions, and, due to the possibility of fixing the damaged prostheses, there is no need to resort to the technician's laboratory. In a previous study we described the experimental phases of intraoral welding, from the in vitro model on animal jaws with evaluations of the temperature variations during welding through thermal chamber and type K thermocouples. In this study we describe the intraoral welding in vivo on human subjects by using, as in the previous study, a fibre-delivered neodymium:yttrium-aluminum-garnet (Nd:YAG) laser. The in vivo phase allowed a restored prosthesis to be positioned and intraorally welded in the upper central sector with optimal results both in patient's comfort and in aesthetic effects. This first in vivo test confirmed that the use of a laser technique for the intraoral welding of metal prostheses is possible, with no particular problems and risks for the biological structures close to the welding zone
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Low energy KTP laser in oral soft tissue surgery: A 52 patients clinical study.
No full textOBJECTIVES: Since 1962 laser appliances have been used for soft tissues surgery of oral cavity with significant advantages compared to the traditional instruments: excellent bleeding control, possibility to avoid the use of suture, good patient compliance thanks to a decrease of intra- and post-operative discomfort and biostimulating effect. Unfortunately, the wavelengths so far used have been seen to cause, in association with an excellent ablation capacity, heat damage of the tissues that can decrease healing process and cause a greater discomfort to patients. To evaluate the laser-assisted KTP laser surgery at low power in terms of characteristics of intervention and patients compliance.
STUDY DESIGN: In this study, we describe the application of a new and recently introduced in dentistry wavelength, the KTP laser (532 nm), used with low power parameter (1 Watt - CW), evaluating the time of interventions and, by a Numerical Rating Scale, the intra and postoperative pain.
RESULTS: KTP laser used at low power permits to obtain good pain control during operations that were carried out with only a topic anaesthetic (EMLA, Astratech), as shown in VAS tests. Good healing with limited or absent burning areas in treated portion of tissue.
CONCLUSIONS: These preliminary study allows us to affirm that KTP laser with low parameters permits to perform oral surgery with good pain control and good wound healing. A greater number of clinical cases are however necessary to confirm the result obtained
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