Transmissão de luz emitida por fotopolimerizador multi-picos através de braquetes cerâmicos mono e policristalinos

Abstract

Objective: To evaluate light transmission through monocrystalline and polycrystalline ceramic brackets using a multi-peak light-curing unit (LCU). Materials and Methods: In vitro study with seventeen ceramic brackets: five monocrystalline (IceramS, InspireIce, Luminous, Radiance, Safira) and twelve polycrystalline (CeramicSLI, ClarityAdvancedCeramic, DamonClear, Iceclear, Iceram, Iceram, In-OvationC, In-Vu, Inflexion, OvationC, PolySafira, and Translux). LCU power and emission spectrum in normal and ortho modes were measured at zero mm from the integrating sphere aperture and transmitted through each bracket using an integrating sphere connected to a spectrometer. Irradiance and transmitted energy were calculated. Beam profiles were obtained via laser beam profiler. Data were analyzed by two-way ANOVA and Tukey's test (α = 0.05). Results: All brackets significantly reduced radiant power, irradiance, and energy compared to the light emitted by the LCU (P < 0.001). PolySafira and IceramP showed higher light transmission, while CeramicSLI and In-Vu showed the lowest values. Light transmission was not influenced by the crystalline structure. The ortho mode increased radiant power and irradiance but reduced total energy compared to the standard mode (P < 0.001). Conclusion: Light transmission depends on bracket design and optical properties, rather than crystalline structure. The activation mode modifies light emission; the ortho mode increases irradiance but reduces total energy, which is lower than required for light-activation of orthodontic resins, a factor that should be considered when selecting polymerization protocols. Keywords: Orthodontic Brackets; Ceramics; Curing Lights Dental; Photopolymerization.