Clareamento dental: com ou sem fotoativação? / Dental whitening: with or without photoactivation?

Dentre os procedimentos estéticos, o clareamento dental é o mais conservador, pois envolve apenas o uso de substâncias clareadoras associadas ou não à aplicação de agente físico, promovendo, desse modo, mudanças cromáticas nos tecidos dentais. Entretanto, alterações pulpares e estruturais do esmalte e da dentina em dentes clareados têm sido observadas, sobretudo quando se utiliza fonte de luz ou de calor para acelerar a reação do peróxido de hidrogênio durante o clareamento. Dessa forma, o objetivo deste trabalho é revisar a literatura a respeito das vantagens e desvantagens em se realizar o clareamento com ou sem o uso de luz, abordando-se a efetividade dos agentes clareadores e os possíveis efeitos aos tecidos dentais. Para tanto, publicações científicas foram selecionadas conforme os propósitos do estudo. A partir do levantamento bibliográfico, observou-se que o clareamento dental com a utilização de fontes luminosas pode ou não trazer prejuízo intrapulpar, dependendo da intensidade e do tipo de luz utilizada

Among the cosmetic procedures, tooth whitening is the most conservative, since it involves only the use of bleaching substances associated or not to the application of physical agent, promoting thereby chromatic changes in dental tissues. However, pulp and structural changes of enamel and dentin in teeth whitened have been observed, especially when using a source of light or heat to accelerate the reaction of hydrogen peroxide during bleaching. Thus, the objective of this study is to review the literature on the advantages and disadvantages of performing bleaching with or without the use of light, addressing the effectiveness of bleaching agents and the possible effects on dental tissues. This is why scientific publications were selected according to the purposes of this study. From the literature survey, it was observed that the tooth whitening with the use of light sources may or may not bring harm intrapulpal, depending on the intensity and type of light used

Influence of photoactivation source on restorative materials and enamel demineralization.

OBJECTIVE: The objective of this study was to evaluate the influence of the photoactivation source on the polymerization depth of restorative materials and its effects on resistance to enamel demineralization. BACKGROUND DATA: Argon-ion laser (AL) irradiation itself provides a reduced depth of caries lesions in sound enamel. METHODS: Eighteen human teeth were sectioned into 36 blocks and distributed into two groups according to the respective restorative material: resin-modified glass ionomer material (RMGI) (Vitremer-3M ESPE; A3; n=18) and composite resin (CR) (Z350-3M ESPE; n=18). Each group was subdivided into three subgroups and activated by a quartz-tungsten-halogen (QTH) lamp, an AL, or a light-emitting diode (LED) (n=6). Knoop microhardness (KHN) analysis of the materials was evaluated at two different depths: 0 and 1.6 mm from the enamel surface. The blocks were thermocycled and submitted to five demineralization-remineralization cycles at 37°C. The KHN values of the enamel surface (0 mm) were evaluated. The specimens were longitudinally sectioned, and the restorative material was evaluated at a depth of 1.6 mm. Data were evaluated by two way analysis of variance (ANOVA) and Tukey tests (p<0.05). The evaluation of subsuperficial enamel demineralization by KHN analysis was conducted by seven indentations located at 100 µm from the restored cavity. Data were evaluated by three way ANOVA and Tukey tests (p<0.05). RESULTS: Comparing the two restorative materials, the KHN values at the surface (0 mm) were greater for CR, whereas at 1.6 mm, they were greater for RMGI. In addition, there was less development of enamel demineralization around RMGI restorations than CR restorations. Moreover, there were statistically significant differences on subsuperficial enamel demineralization between the two restorative materials and between the three photoactivation methods (p<0.05); RMGI presented the highest KHN values, and QTH and AL presented the lowest. CONCLUSIONS: The photoactivation source did not influence superficial enamel demineralization, but LED activation positively influenced the subsuperficial microhardness of enamel.

Tratamento de superfície e cimentação adesiva de cerâmicas aluminizadas: revisão de literatura / Surface treatment and adhesive cementing of glass-infiltrated Alumina ceramic: review of the literature

Nas últimas décadas, as cerâmicas odontológicas, os sistemas adesivos e os agentes cimentantes têm sido estudados, objetivando encontrar novos mecanismos que permitam uma união mais efetiva e duradoura entre os tecidos dentários duros e a restauração indireta. Sabe-se que oprocedimento de preparo para cerâmicas feldspáticas requer o condicionamento da sua superfície com ácido fluorídrico prévio à cimentação. Entretanto, para cerâmicas aluminizadas, em face dassuas características estruturais, o condicionamento ácido não é indicado. Dessa maneira, a escolha do preparo de superfície e do sistema cimentante resinoso torna-se extremamente importante quandose almeja o sucesso do tratamento reabilitador. A presente revisão de literatura teve como objetivo buscar as bases científicas relativas às técnicas alternativas de tratamento superficial e aos agentescimentantes para cerâmicas reforçadas. Para tanto, artigos publicados no período de 1998 a 2007 foram selecionados e analisados, permitindo aos autores concluírem que ainda não há consenso a respeito dos métodos alternativos de tratamento de superfície para os sistemas cerâmicos à base de alumina e da seleção de materiais cimentantes que, usados em conjunto, apresentem resistência de união plenamente satisfatória. Portanto, mais estudos são requeridos a fim de testar e compreenderos mecanismos adesivos responsáveis pela estabilidade das restaurações indiretas a longo prazo.

In the last decades, the dental ceramics, the adhesive systems and luting agents have been studied, objectifying to find new mechanisms that allow to an a more effective and durable bond between the hard tissue dental and indirect restoration. It is known that the procedure ofpreparation for feldspathic ceramics requires the surface conditioning with hydrofluoric acid prior to cementing. Meanwhile alumina ceramics, in face of its structural features, the acid etching is not indicated. In this way, the choice of surface preparation and the resin luting system becomes extremely important when it seeks to successful rehabilitation treatment. The present review of literature had as objective to search cientific bases about alternative techniques of the surfacetreatment and luting agents for high-strength ceramics. For in such a way, articles published in the period 1998 to 2007 had been selected and analyzed, allowing to the authors to conclude that still there is not enough consensus and evidences, regarding the use of alternative methods of surface treatment for the ceramic-based alumina systems and the selection of luting materials that jointly present fully satisfactory strength bond. Therefore, further studies are required in order to test andto understand the responsible adhesive mechanisms by the stability of the indirect restorations in the long term.