Color and surface temperature variation during bleaching in human devitalized primary teeth: an in vitro study.

This study's purpose was to make an in vitro assessment of 2 whitening techniques in primary teeth, regarding color and temperature surface variation, during dental bleaching using different catalytic sources. Twenty-one extracted human upper central deciduous incisors were used in this in vitro study. The teeth were darkened with human blood for a period of 21 days. After preparing the teeth, they were randomly distributed into 2 groups, according to bleaching source of activation: (1) a diode laser (DL) group; and (2) a halogen lamp (HL) group. The bleaching process was performed, according to the manufacturer's guidelines, using Whiteness HP (FGM, Joinville, Brazil). The color was assessed by spectrophotometer (CIELab) and the VITA scale (3M) before and immediately after tooth whitening. The temperature increase in the radicular surface during the bleaching was registered with a thermographic camera ThermaCAM SC 3000 (Flir Systems, Danderyd, Sweden) at the Nuclear and Energy Research Institute, IPEN-CNEN (São Paulo, Brazil). There was no significant difference between the groups in terms of color changes, but there was a statistically significant difference for temperature variation. The use of a diode laser and halogen lamp both promoted whitening in devitalized primary teeth in vitro. As a catalytic source of energy, the diode laser--with the applied parameters--promoted a smaller temperature increase compared to the halogen lamp during the bleaching procedure on nonvital primary teeth.

Whitening techniques using the diode laser and halogen lamp in human devitalized primary teeth.

The aim of this study was to make an in vivo assessment of 2 whitening techniques in deciduous teeth, with the variable being the source of energy activation. Ten upper central incisors darkened by trauma were selected and whitening agent used was a 35% hydrogen peroxide. The teeth were distributed into 2 groups: group 1-activation with an infrared diode laser (GaAlAs), and group 2-activation with a halogen lamp. Assessment of whitening was done by color analysis with the Vita 3D scale at 3 different times: before whitening, immediately after whitening, and 1 week after whitening. A Kruskal-Wallace test showed that there were no significant difference between the 2 groups when comparing group 1 and 2 and comparing 2 and 3 immediately and after 1 week of treatment. Laser activation of the whitening agent was not more effective than halogen light activation for root canal-treated deciduous teeth.

The applications of diode and Er:YAG lasers in labial frenectomy in infant patients.

This paper describes a clinical case of labial frenectomy using different high power lasers: diode (810 nm) and Er:YAG (2940 nm). Considerations are made about specific indications, surgery techniques, and advantages of labial frenectomy using these laser wavelengths. The diode laser has high absorbance by pigmented tissues with hemoglobin, melanin, and collagen chromophores. For this reason, this wavelength is well indicated for surgery in soft tissue (vaporization, incision, coagulation, hemostasis). It is not properly absorbed, however, and should never be used in contact with hard tissues (bone). The Er:YAG laser has high absorbance to water and mineral apatite, making this wavelength useful and safe for the ablation of hard tissues. In the labial frenectomy clinical procedure, a combined technique is suggested: using the diode laser in soft tissues and the Er:YAG laser in periosteal bone tissues and for removal of final collagen fibers. It is important for the professional to understand the physical characteristics of the different laser wavelengths and their interaction with biological tissues to assure that they are used in a safe way, and that the benefits of this technology can be provided to infant patients.

Anomalias de desenvolvimento e retardo mental provocados pela exposição às radiações ionizantes: atenção à gestante e criança / development abnormalities and mental retardation caused by the exposure to ionizing radiation: attention to pregnant women and children

Este estudo objetiva uma análise das anomalias de desenvolvimento e retado mental provocados pelas radiações ionizantes, no intuito de orientar os profissionais de saúde quanto aos riscos das radiografias de diagnóstico em gestantes e crianças. É universalmente conhecido que as radiações ionizantes tem grande potencial nocivo aos tecidos vivos e os estudos a respeito de seus efeitos foram realizados a partir de acidentes nucleares ambientais. O maior problema em se avaliar o risco dos efeitos é que não se conhece um método de distinção entre os efeitos induzidos pela radiação daqueles provenientes de outras fontes. O feto, que se encontra em fase de organogênese, e as crianças, apresentam grande radiossensibilidade, pois estão em processo de crescimento e desenvolvimento, sendo que distúrbios podem ocorrer durante esta fase, acarretando anomalias de desenvolvimento. Retardo mental pode ser observado em embriões que sofreram irradiação na época de desenvolvimento do sistema nervoso central (durante a 8ª e a 25ª semana gestacional). Os efeitos biológicos provenientes das radiações ionizantes variam de acordo com diversos fatores (dose, radiossensibilidade tecidual) e o conceito de altas e baixas doses é subjetivo. Apesar das tomadas radiográficas odontológicas serem consideradas de baixo risco, seu efeito pode não ser considerado insignificante, pois radiações têm ação cumulativa. Pelo exposto, são necessários cuidados para minimizar o risco, utilizando filmes ultra-rápidos, avental de chumbo, indicação e técnicas radiográficas precisas, principalmente quando se de crianças e gestantes. Observa-se necessidade de padronização das unidades de radiação mencionadas na literatura, para facilitar uma comparação entre trabalhos científicos