Inhaltsverzeichnis:J Oral Laser Applications 9 (2009), Nr. 4 (07.01.2010)
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Some orthodontic procedures are improved by the therapeutic use of laser, bringing some advantages for both patient and practitioner, by either reducing the time of procedures or pain induced by the activation of devices during the treatment. This therapy deserves further analysis of the biological principles, to provide insight into the effects of laser on different cell lineages involved.
The aim of this article is to provide a review of the literature about laser effects on fibroblasts, osteoblasts and osteoclasts, studied in animal models and in human subjects. The review indicates that the application of low energy laser during orthodontic movement is safe in terms of the cellular effects, and there is a strong basis to explain the significant favorable clinical results reported.
Schlagwörter: orthodontics, laser therapy, oral cell biology, fibroblasts, osteoblasts, osteoclasts
Purpose: The aim of this study was to determine residual heat deposition in hard dental tissues during ablation with Erbium lasers.
Materials and Methods: Residual heat deposition was obtained from measured irradiated hard tissue temperature decay characteristics immediately following Erbium laser pulses. A comparison of the heating effects of the two most commonly used Erbium lasers in laser dentistry, namely Er:YAG and Er,Cr:YSGG, was made.
Results: The measured residual heat was larger in enamel than in dentin for both laser sources. The amount of the unwanted residual heat that remains deposited in the tooth is for the H mode Er,Cr:YSGG laser twice as great, and for the S mode Er,Cr:YSGG laser more than 3 times as great as the deposited heat with the MSP mode Er:YAG laser.
Conclusion: For Er,Cr:YSGG lasers, a larger share of the total absorbed laser energy remained in the tooth in the form of heat. This explains, at least partially, the observed lower ablation efficacy of Er,Cr:YSGG lasers compared to Er:YAG lasers.
Schlagwörter: Er:YAG, Er,Cr:YSGG, erbium laser, heat deposition, dental laser, hard dental tissues
Purpose: CO2 laser biopsy and photo-thermal ablation has been accepted as a diagnostic/treatment modality for leukoplakia. We hypothesized that CO2 laser would be an excellent tool for diagnosis/treatment of leukoplakia, facilitating improved outcome and patient satisfaction.
Materials and Methods: A retrospective study was performed comparing CO2 laser to the standard surgical technique, considering the treatment protocol and patient compliance. In toto, 8 patients were diagnosed using the clinical features prominent for leukoplakia. These were further subdivided into two categories. Category A defined patients undergoing bilateral treatment with CO2 laser and the traditional surgical technique. Category B was further divided into two subcategories, in which patients underwent either CO2 laser or the traditional technique. Immediately postoperatively, the samples thus obtained were subjected to histopathological study. After the treatment protocol, the patients were asked to determine pain on the faces scale and numerical rating scale. A follow-up of the patients was done after 7, 14 and 21 days.
Results: The study showed improved operating conditions, more rapid healing than for other thermal instruments, minimal tissue handling, and improved patient compliance.
Conclusion: Because of its comfort level for the operator and the patient's benefit, CO2 laser can be recommended in oral therapy. It is a precise means of removing soft tissue lesions in selected patients. Patient postoperative satisfaction after laser excision was greater when compared with those who had conventional excisions. Postoperative pain was less, as was the pain experienced during the first week of recovery.
Schlagwörter: biopsy, leukoplakia, CO2 lasers, dysplasia, scalpel, ablation
Different external bleaching procedures utilizing highly concentrated hydrogen peroxide formulations can be used for tooth bleaching and tooth whitening. Whitening is the removal of superficial discoloration of the teeth, whereas bleaching constitutes the removal of stains on and in tooth substance by means of oxygen radicals. Light can be used to enhance or accelerate the bleaching process. In most cases, the effect of light is limited to heating of the bleaching formulation and this process differs from "true photobleaching". Photobleaching or photodynamic bleaching is a process where light from a laser or non-coherent light source is used to drive molecular changes in light-sensitive compounds, and where the discoloration or bleaching of the teeth is caused as a result of the generation of reactive oxygen species. Secondly, it is also possible to photobleach colored organic compounds and especially those that are inherently resistant to the action of the oxygen free radicals. At present, true photobleaching can only be performed with the KTP laser (532 nm) in conjunction with a red colored highly concentrated hydrogen peroxide gel. Furthermore, it has also been demonstrated that the use of the KTP laser with the Smart Bleach system is safe: no intrapulpal temperature elevations beyond 5.5°C have been registered, and there is no risk of enamel microhardness decrease. KTP laser bleaching can be considered a noninvasive esthetic procedure, and hence is the least invasive procedure of what is called today minimally invasive dentistry.
Schlagwörter: laser bleaching, laser tooth whitening, KTP laser, photobleaching, power bleaching, tetracyclines
Esthetics has become a significant aspect of dentistry and clinicians are faced with achieving acceptable gingival esthetics as well as addressing biological and functional problems. The gingiva is the most commonly affected intraoral tissue that is responsible for a displeasing appearance. Melanin pigmentation often occurs in the gingiva as a result of an abnormal deposition of melanin, due to which the gums may appear black, but the principles, techniques, and management of the problems associated with gingival melanin pigmentation are still not fully established. Depigmentation procedures such as scalpel surgery, gingivectomy with free gingival autografting, electrosurgery, cryosurgery, abrasion with diamond bur, Nd:YAG laser, semiconductor diode laser, and CO2 laser have been employed for removal of melanin pigmentation.
The following case report describes three different surgical depigmentation techniques: scalpel blade surgery, abrasion with diamond bur, and semiconductor diode laser. The diode laser is a solid-state semiconductor laser that typically uses a combination of Gallium (Ga), Arsenide (Ar), and other elements, such as aluminium (Al) and indium (In) to change electrical energy into light energy. Better results were achieved with semiconductor diode laser than conventional scalpel blade and abrasion with bur.
Schlagwörter: diode laser, hyperpigmentation, repigmentation
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