Способ переработки бериллиевого сырья

The aim of this in vitro study was to evaluate some parameters of dental etching when irradiated with an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser. One-hundred sound human third molars were selected and randomly distributed into ten groups (n = 10). The class V cavities of group 1 (control) were prepared with a bur and etched with 37% phosphoric acid, while groups G2 to G10, were prepared with laser (5 W, 88.46 J/cm(2), 90/70% air/water) and etched with the following powers: G3 and G4, 0.25 W; G5 and G6, 0.5 W; G7 and G8, 0.75 W; G9 and G10, 1 W. Group G2 received no laser etching. Prior to restoration, G2, G4, G6, G8 and G10 received acid etching. After restoration, all samples were submitted to a microleakage test. According to statistical analysis (Kruskal-Wallis and Dunn`s tests), G10 presented the lowest microleakage values (P < 0.05). The other groups showed no differences between them. Etching with Er,Cr:YSGG laser (1 W) followed by phosphoric acid was effective in reducing the microleakage of class V restorations.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[98/14270-8]Biolase for the interchange accomplished with the Laboratorio Especial de Laser em Odontologia (LELO

Análise quantitativa da remoção de esmalte dental durante a técnica de microabrasão

Objetivo: Quantificar, por meio de perfilometria, a profundidade de esmalte dental removido durante o emprego de uma técnica de microabrasão utilizando-se ácido clorídrico e abrasão manual com espátula plástica. Método: Trinta e seis espécimes obtidos de terceiros molares humanos foram polidos, para obtenção de superfícies planas, e divididos em 3 grupos (n = 12) de acordo com os diferentes tratamentos recebidos: tratamento placebo com água deionizada, como controle negativo (CG); microabrasão com ácido clorídrico a 6.6%, OpalustreTM (G1); e ácido clorídrico a 6%, Whiteness RMTM (G2). A microabrasão foi realizada, de forma padronizada, submetendo os espécimes a 4 ciclos de 10 segundos cada e abrasão manual utilizando-se uma espátula plástica com carga de 200 g. A perda da superfície de esmalte foi medida após cada um dos ciclos de tratamento por meio de perfilômetro de contato. Resultados: Após os primeiros 10 segundos de abrasão, já foi encontrada perda de esmalte em ambos os grupos tratados (G1 e G2). Nos grupos G1 e G2, a cada ciclo de 10 segundos, foi observado um aumento significativo na perda de esmalte (p ≤ 0.05). Após 4 abrasões de 10 segundos cada, as médias de perda de esmalte nos grupos tratados foram 46.04 μm (G1) e 54.65 μm (G2). Foi encontrada uma diferença significativa entre G1 e G2 com relação à perda de esmalte após 30 e 40 segundos de microabrasão. Relevância: Os resultados deste estudo fornecem referências para a realização do procedimento de microabrasão em esmalte dental com segurança, utilizando-se ácido clorídrico e abrasão manual com espátula plástica.Objective: To quantify, by means of profi lometry, the removal of dental enamel during the use of a microabrasion technique involving the use of hydrochloric acid and manual abrasion with a plastic spatula. Method: Thirty six specimens obtained from human third molars were polished to obtain fl at surfaces and divided into 3 groups (n = 12) according to the different treatments received: A placebo treatment with deionized water as a negative control (CG); microabrasion with 6.6% hydrochloric acid, OpalustreTM (G1); and microabrasion with 6% hydrochloric acid, Whiteness RMTM (G2). The microabrasion was performed in a standardized manner by submitting the specimens to 4 cycles of 10 seconds each and manual abrasion using a plastic spatula (200 g load). The loss of enamel surface was measured after each cycle of treatment by contact profi lometry. Results: Enamel loss was already observed after the fi rst 10 seconds of abrasion with hydrochloric acid in both treated groups (G1 and G2). After 4 abrasions of 10 seconds each, the average fi nal enamel losses in the treated groups were 46.04 μm (G1) and 54.65 μm (G2). In the G1 and G2 groups, a signifi cant increase in enamel wear was detected in each cycle in comparison to the control group (p ≤ 0.05). A signifi cant difference in enamel loss between G1 and G2 was found after 30 and 40 seconds of microabrasion. Relevance: The results of this study provide objective data for safely performing the microabrasion technique on dental enamel using hydrochloric acid and manual abrasion using a plastic spatula

Lasers in Esthetic Dentistry: Soft Tissue Photobiomodulation, Hard Tissue Decontamination, and Ceramics Conditioning

The increasing concern and the search for conservative dental treatments have resulted in the development of several new technologies. Low and high power lasers can be cited as one of these new technologies. Low power lasers act at cellular level leading to pain reduction, modulation of inflammation, and improvement of tissue healing. High power lasers act by increasing temperature and have the potential to promote microbial reduction and ablation of hard and soft tissues. The clinical application of both low and high power lasers requires specific knowledge concerning laser interaction with biological tissues, so that the correct irradiation protocol can be established. The present case report describes the clinical steps of two metal-ceramic crowns development in a 60-year-old patient. Three different laser wavelengths were applied throughout the treatment with different purposes: Nd:YAG laser (1,064 nm) for dentin decontamination, diode (660 nm) for soft tissue biomodulation, and Er:YAG laser (2,940 nm) for inner ceramic surface conditioning. Lasers were successfully applied in the present case report as coadjutant in the treatment. This coadjutant technology can be a potential tool to assist treatment to reach the final success

Sealer penetration and marginal permeability after apicoectomy varying retrocavity preparation and retrofilling material

Apicoectomy failure is generally related to inappropriate marginal sealing of the retrocavity, which allows percolation of microorganisms and their products from root canal system to periapex. This study evaluated tubular penetration of canal sealers and marginal permeability after retrocavity irradiation with Er;Cr:YSGG laser and retrofilling with MTA or cyanoacrylate. Twenty-two single-rooted teeth were decoronated and endodontically treated, their apical 3 mm were resected and the root ends were retroprepared with a low-speed bur. Twenty roots were randomly assigned to 4 groups (n=5): GI and GII - retrofilling with MTA and cyanoacrylate, respectively; GIII and GIV - retrocavity irradiation with Er;Cr:YSGG laser (2.78 µm, 4 W, 20 Hz, 70.8 J/cm²) and retrofilling with MTA and cyanoacrylate, respectively. The remaining 2 roots served as positive and negative controls. The analysis of rhodamine B dye infiltration (p=0.05) demonstrated that laser irradiation and MTA retrofilling presented significantly higher permeability rates (p<0.05). Retrofilling with cyanoacrylate showed significantly lower permeability, either when laser was used or not on retrocavity. SEM analysis depicted more cyanoacrylate penetration through dentinal tubules when compared to MTA, suggesting a more efficient marginal sealing. Based on these results, it may be concluded that cyanoacrylate provided a less permeable retrofilling regardless of the retropreparation method, suggesting a more favorable condition to the establishment of the periapical healing

Laser Phototherapy for Stevens-Johnson Syndrome: A Case Report

Background and Objective: Stevens-Johnson syndrome (SJS) is a life-threatening dermatosis characterized by epidermal sloughing and stomatitis. We report the case of a 7-year-old boy in whom laser phototherapy (LPT) was highly effective in reversing the effects of an initial episode of SJS that had apparently developed in association with treatment with phenobarbital for a seizure disorder. The patient was first seen in the intensive care unit (ICU) of our institution with fever, cutaneous lesions on his extremities, trunk, face, and neck; mucosal involvement of his genitalia and eyes (conjunctivitis); ulcerative intraoral lesions; and swollen, crusted, and bleeding lips. He reported severe pain at the sites of his intraoral and skin lesions and was unable to eat, speak, swallow, or open his mouth. Materials and Methods: Trying to prevent and minimize secondary infections, gastric problems, pain, and other complications, the patient was given clindamycin, ranitidine, dipyrone, diphenhydramine (Benadryl) drops, and morphine. In addition, he was instructed to use bicarbonate solution and Ketoconazole (Xylogel) in the oral cavity. Because of the lack of progress of the patient, the LPT was selected. Results: At 5 days after the initial session of LPT, the patient was able to eat gelatin, and on the following day, the number and severity of his intraoral lesions and his labial crusting and swelling had diminished. By 6 days after his initial session of LPT, most of the patient's intraoral lesions had disappeared, and the few that remained were painless; the patient was able to eat solid food by himself and was removed from the ICU. Ten sessions of LPT were conducted in the hospital. The patient underwent three further and consecutive sessions at the School of Dentistry, when complete healing of his oral lesions was observed. Conclusion: The outcome in this case suggests that LPT may be a new adjuvant modality for SJS complications.Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP

Calcitonin, sodium alendronate and high intensity laser in the treatment of traumatized teeth: a preliminary study

The aim of this study was to evaluate the influence of erbium:yttrium-aluminum-garnet (Er:YAG) laser compared with traditional treatment on dentin permeability to calcitonin and sodium alendronate. Forty bovine roots were sectioned and divided into eight groups. Groups 1 and 2 (G1/G2) were immersed in saline solution; G1T/G2T were immersed in ethylene diamine tetra-acetic acid plus sodium lauryl ether sulfate (EDTA-T) and sodium hypochlorite (NaOCl); G1I/G2I were irradiated with Er:YAG laser (2.94 mu m, 6 Hz, 40.4 J/cm(2)); G1TI/G2TI were immersed in EDTA-T, NaOCl and subjected to Er:YAG irradiation. After 4 h the radioactivity of the saline solution was measured. Statistical analysis revealed a significant difference (P < 0.05) when the groups treated with EDTA-T and NaOCl followed by Er:YAG laser irradiation were compared with the groups treated with EDTA-T only and with the groups that received no treatment. Er:YAG laser associated with traditional procedures significantly increased the diffusion of calcitonin and sodium alendronate through dentin. All groups showed calcitonin and sodium alendronate diffusion.The International Association for Dental Research (IADR

Microtensile bond strength of composite resin to glass-infiltrated alumina composite conditioned with Er,Cr:YSGG laser

Tribochemical silica-coating is the recommended conditioning method for improving glass-infiltrated alumina composite adhesion to resin cement. High-intensity lasers have been considered as an alternative for this purpose. This study evaluated the morphological effects of Er,Cr:YSGG laser irradiation on aluminous ceramic, and verified the microtensile bond strength of composite resin to ceramic following silica coating or laser irradiation. In-Ceram Alumina ceramic blocks were polished, submitted to airborne particle abrasion (110 mu m Al(2)O(3)), and conditioned with: (CG) tribochemical silica coating (110 mu m SiO(2)) + silanization (control group); (L1-L10) Er,Cr:YSGG laser (2.78 mu m, 20 Hz, 0.5 to 5.0 W) + silanization. Composite resin blocks were cemented to the ceramic blocks with resin cement. These sets were stored in 37A degrees C distilled water (24 h), embedded in acrylic resin, and sectioned to produce bar specimens that were submitted to microtensile testing. Bond strength values (MPa) were statistically analyzed (alpha a parts per thousand currency sign0.05), and failure modes were determined. Additional ceramic blocks were conditioned for qualitative analysis of the topography under SEM. There were no significant differences among silicatization and laser treatments (p &gt; 0.05). Microtensile bond strength ranged from 19.2 to 27.9 MPa, and coefficients of variation ranged from 30 to 55%. Mixed failure of adhesive interface was predominant in all groups (75-96%). No chromatic alteration, cracks or melting were observed after laser irradiation with all parameters tested. Surface conditioning of glass-infiltrated alumina composite with Er,Cr:YSGG laser should be considered an innovative alternative for promoting adhesion of ceramics to resin cement, since it resulted in similar bond strength values compared to the tribochemical treatment.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico) [303798/2005-0]FAPESP/CEPID (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo/Centros de Pesquisa, Inovacao e Difusao)FAPESP/CEPID (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo/Centros de Pesquisa, Inovacao e Difusao) [98/14270-8